To build my own home-made plane - a biplane - has been my dream since childhood. However, I was able to implement it not so long ago, although I paved the way to the sky in military aviation, and then on a delta-flying. Then he built an airplane. But the lack of experience and knowledge in this matter gave a corresponding result - the plane never took off.
Failure not only discouraged the desire to build aircraft, but cooled the ardor thoroughly - a lot of time and effort was spent. And to revive this desire helped, in general, the case when it became possible to inexpensively purchase some parts from the decommissioned An-2 aircraft, known more popularly under the name "Corn".
And I bought only ailerons with trims and flaps. But from them it was already possible to make wings for a light biplane aircraft. Well, the wing is almost half an aircraft! Why did you decide to build a biplane? Because the area of the ailerons was not enough for the monoplane. But for a biplane - it was enough, and the wings from the An-2 ailerons even shortened a little.
Ailerons stand only on the lower wing. They are made of twin aileron trim tabs of the same An-2 aircraft and are suspended on the wing on conventional piano loops. To increase the efficiency of aircraft control along the trailing edge of the ailerons, wooden (pine) triangular slats 10 mm high are glued on top and covered with strips of sheathing fabric.
The biplane aircraft was conceived as a training aircraft, and according to the classification it belongs to ultralight vehicles (ultralights). By design, a home-made biplane is a single-seat single-post biplane with a tricycle landing gear with a steered tail wheel.
I could not find a prototype, and therefore I decided to design and build according to the classical scheme and, as motorists say, without additional options, that is, in the simplest version with an open cockpit. The upper wing of the "Grasshopper" is raised above the fuselage (like a parasol) and is fixed slightly in front of the cockpit on a support made of duralumin pipes (from the rods of the An-2 ailerons) in the form of an inclined pyramid.
The wing is detachable, it consists of two consoles, the joint between which is covered by an overlay. Wing set - metal (duralumin), lining - linen with enamel impregnation. The wing tips and root parts of the wing consoles are also sheathed with a thin duralumin sheet. The upper wing consoles are additionally reinforced with struts extending from the inter-wing struts attachment points to the lower fuselage spars.
The air pressure receiver is fixed at a distance of 650 mm from the end of the left upper wing console. The lower wing consoles are also detachable, attached to the lower fuselage spars (on the sides of the cockpit). The gaps between the root part and the fuselage are covered with linen (soaked in enamel) fairings, which are attached to the consoles with Velcro bands - burdocks.
The installation angle of the upper wing is 2 degrees, the lower wing is 0. The transverse V at the upper wing is 0, and at the lower one - 2 degrees. The sweep angle of the upper wing is 4 degrees, and the lower wing is 5 degrees.
The lower and upper consoles of each wing are interconnected by struts made, like the struts, of duralumin pipes from the control rods of the An-2 aircraft. The fuselage frame of a homemade biplane is truss, welded from steel thin-walled (1.2 mm) pipes with an outer diameter of 18 mm.
Its basis is four spars: two upper and two lower. On the sides, a pair of spars (one upper and one lower) are connected by an equal number and equally spaced struts and struts and form two symmetrical trusses.
Pairs of upper and lower spars are connected by cross members and jibs, but their number and location at the top and bottom are often not the same. Where the location of the cross members and struts coincide, they form a frame. Forming arcs are welded on top of the front rectangular frames.
The rest (rear) fuselage frames are triangular, isosceles. The frame is covered with unbleached calico, which is then impregnated with homemade "enamel" - celluloid dissolved in acetone. This coating has proven itself well among amateur aircraft designers.
The front part of the biplane fuselage (up to the cockpit) on the left side in flight is sheathed with thin plastic panels. The panels are removable for easy ground access to the controls in the cab and under the engine. The bottom of the fuselage is made of duralumin sheet 1 mm thick. The tail unit of an airplane - a biplane - is a classic one. All of its elements are flat.
The keel, stabilizer, rudder and rudder frames are welded from thin-walled steel pipes with a diameter of 16 mm. The linen sheathing is sewn to the details of the frames, and the seams are additionally glued with strips of the same enamel-impregnated coarse calico fabric. The stabilizer consists of two halves that are attached to the keel.
To do this, an M10 hairpin is passed over the fuselage through the keel near the leading edge, and a tubular axle with a diameter of 14 mm at the trailing edge. Lugs with sector grooves are welded to the root rods of the stabilizer halves, which serve to set the horizontal tail at the required angle, depending on the pilot's weight.
Each half is put on a hairpin with an eyelet and secured with a nut, and the trailing edge tube - on the axle and is attracted to the keel by a brace made of steel wire with a diameter of 4 mm. From the editor. To prevent spontaneous rotation of the stabilizer in flight, it is advisable to make several holes for the hairpin instead of a sector groove in the ears.
Now on the biplane plane there is a propeller-driven installation with an engine from the Ufa Engine Plant UMZ 440-02 (the plant equips the Lynx snowmobiles with such motors) with a planetary gearbox and a two-blade propeller.
431 cm3 engine with 40 hp. with air-cooled speed up to 6000 rpm, two-cylinder, two-stroke, with separate lubrication, runs on gasoline, starting with AI-76. Carburetor - K68R Air cooling system - although self-made, but effective.
It is made according to the same scheme as in the Walter-Minor aircraft engines: with a truncated cone-shaped air intake and deflectors on the cylinders. Previously, a biplane plane was equipped with a modernized engine from an outboard motor "Whirlwind" with a capacity of only 30 hp. and V-belt transmission (gear ratio 2.5). But the plane flew confidently with them too.
But the pulling two-blade monoblock (made of pine re-glue) homemade screw with a diameter of 1400 mm and a pitch of 800 mm has not yet changed, although I plan to replace it with a more suitable one. A planetary gearbox with a gear ratio of 2.22 ... the new engine got it from some foreign car.
The muffler for the engine is made of a ten-liter cylinder of a foam fire extinguisher. The fuel tank with a capacity of 17 liters is from the tank of an old washing machine - it is made of stainless steel. Installed behind the dashboard. The hood is made of thin-sheet duralumin.
It has on the sides of the grill for the outlet of heated air and on the right there is also a hatch with a cover for the outlet of the cord with a handle - they start the engine. The propeller-driven installation on a homemade biplane is suspended on a simple motor frame in the form of two braces with struts, the rear ends of which are fixed on the racks of the front frame-frame of the fuselage frame. The electrical equipment of the aircraft is 12-volt.
The main landing gear legs are welded from pieces of steel pipe with a diameter of 30 mm, and their struts - from a pipe with a diameter of 22 mm. The shock absorber is a rubber cord wound around the front tubes of the struts and the trapezoid of the fuselage frame. The wheels of the main landing gear are non-braking with a diameter of 360 mm - from a mini-mock, they have reinforced hubs. The rear support has a spring-type shock absorber and a steering wheel with a diameter of 80 mm (from an aircraft ladder).
Aileron and elevator control - hard, from the aircraft control stick through rods made of duralumin tubes; rudder and tail wheel - cable, from the pedals. The construction of the aircraft was completed in 2004, and the pilot E.V. Yakovlev tested it.
The biplane aircraft passed the technical commission. Made quite long flights in a circle around the airfield. A fuel reserve of 17 liters is enough for about an hour and a half of flight, taking into account the aeronautical reserve. Two Evgenias gave me very useful advice and consultations during the construction of the aircraft: Sherstnev and Yakovlev, for which I am very grateful to them.
Homemade biplane "Grasshopper": 1 - air propeller (two-bladed, monoblock. Diameter 1400.1 = 800); 2- muffler; 3 - cockpit fairing; 4- hood; 5 - brace of the upper wing console (2 pcs.); 6- rack (2 pcs.); 7 - pylon of the upper wing; 8- transparent visor; 9 - fuselage; 10 keel; 11 - steering wheel; 12 - tail support; 13 - tail steering wheel; 14-main landing gear (2 pcs.); 15 - main wheel (2 pcs.); 16 - the right console of the upper wing; 17-left upper wing console; 18 - the right console of the lower wing; 19-left lower wing console; 20-air pressure receiver; 21 - overlay for the joint of the upper wing consoles; 22 - brace for stabilizer and keel (2 pcs.); 23 - engine hood with air intake; 24 - gas baffle plate; 25 - stabilizer (2 pcs.); 26 - elevator (2 pcs.); 27-aileron (2 pcs.)
Steel welded frame of the biplane fuselage: 1-upper spar (pipe with a diameter of 18x1, 2 pcs.); 2- lower side members (pipe with a diameter of 18x1, 2 pcs.); 3 - support of the aircraft control stick; 4-spine girder (2 pcs.); 5- - quadrangular frame (pipe with a diameter of 18, 3 pcs.); 6- shaping arc of the first and third frames (pipe with a diameter of 18x1, 2 pcs.); 7 - struts and braces (pipe with a diameter of 18x1, according to the drawing); 8- lugs and lugs for fastening and suspension of structural elements (as required); 9 - trapezoid of fastening with a rubber cord shock absorber of the main landing gear (pipe with a diameter of 18x1); 10-triangular tail frames (tube diameter 18x1, 4 pcs.)
Angles of installation of wing consoles (a - upper wing; b - lower wing): 1 - transverse V; 2-swept wings; 3-angle of installation
Homemade biplane motor mount: I - spar (steel pipe 30x30x2.2 pcs.); 2-spar extension (pipe with a diameter of 22.2 pcs.); 3 - cross member (steel sheet s4); 4 - silent blocks (4 pcs.); 5-eye for fastening the brace (steel sheet s4,2 pcs.); 6 - support bow of the hood (steel wire with a diameter of 8); 7 brace (pipe with a diameter of 22, 2 pcs.)
The main landing gear of the biplane: 1 -wheel (diameter 360, from a mini-mock); 2- wheel hub; .3 - main stand (steel pipe with a diameter of 30); 4 - main brace (steel pipe with a diameter of 22); 5 - shock absorber (rubber band with a diameter of 12); 6 - travel stop of the main rack (cable with a diameter of 3); 7 - trapezoid for mounting the shock absorber (element of the fuselage truss); 8- fuselage truss; 9 additional landing gear (steel rough with a diameter of 22); 10- capture of the shock absorber (pipe with a diameter of 22); 11 - additional brace (steel pipe with a diameter of 22); 12 uprights connection (steel pipe with a diameter of 22)
Instrument gloss (at the bottom, the rudder and tail wheel control pedals on the trapezoid and the rubber borehole shock absorber of the main landing gear are clearly visible): 1 - carburetor throttle control knob; 2 - horizontal speed indicator; 3 - variometer; 4 - screw for fastening the dashboard (3 pcs.); 5 - direction indicator and slip; 6-light signaling engine failure; 7 - ignition switch; 8-cylinder head temperature sensor; 9 - rudder control pedals
On the right side of the hood - a window for the carburetor air filter, engines and engine starting device
The UM Z 440-02 engine from the Lynx snowmobile blended well with the contours of the fuselage and provided the aircraft with good flight data
Flying on your own plane is not a cheap pleasure. Only a few people can afford to buy a factory light-engine aircraft for their money. As for used factory aircraft, they also require a number of additional investments from their new owners: despite the previous technical revisions, the new owner inevitably faces other people's problems. Fortunately, there is a solution to this problem. Home-built aircraft, certified by the EEMU in the experimental category, have become very popular at rallies of aviation enthusiasts.
Aside from the added time to build, the amateur-built RVs, Sonexes, Velocity and many others have earned well-deserved high marks for their low cost and excellent flight performance that rivals their factory counterparts, but as is often the case, there is a downside to home-made: for every completed amateur project, there are several abandoned ones. So in order for the project to become successful, you need to take the right steps, have certain knowledge and be able to apply it.
Step 1. Selecting an airplane model
Perhaps the goal of the project is the main factor influencing the success of the entire event, before the construction is started.
The beginning of an airplane project can be put on a par in importance with a marriage proposal, an important deal, and even the choice of a pet. As in all previous cases, here you need to think over all the subtleties before making a final decision.
Most of those who did not reach the finish line burn out because of trifles. The grace of the Falco plane, aerial acrobatics on Pitts 12 and mischievous flight on Glastar: all can stir up the interest of a future builder to make decisions based on appearance alone. The simplicity of this solution can be deceiving. The essence of the correct decision is not in external attributes, but in the purpose of construction.
Making the right decision requires completely honest and sincere introspection. Of course, many dream of flying like Viktor Chmal or Svetlana Kapanina, but this or that? Each person has his own individuality and his own style of piloting, and it is impossible to live by someone else's experience. You can build an airplane for air tourism and long cross-country flights, but then you find that you are closer to a country picnic on a green lawn with friends 60 kilometers from the flying club. It is important to resolve all your doubts and sincerely think about the dream of a "home plane". After all, the main thing is to improve your life and do more what you really like.
Once you have decided on your dream, choosing a plane will not be difficult. After choosing an aircraft model, it will be time for an examination. A quick look at the 15 year issue of Modelist - Constructor magazine will have a slightly sobering effect - perhaps because most of the airplane models on offer are already out of fashion. The world of home cockpit builders has its own niche in the market, but even with strong motivation to do business in such a territory, it will be difficult from the economic point of view, because the market is very individualized, and trends are replacing each other, like fashion for swimwear. Before you start building, you should carry out preparatory work: analyze in detail the design of the aircraft, call people who have already been involved in this project and look through the list of accidents. Starting work on an outdated project in which parts and assemblies are difficult to obtain is, in principle, an expensive and costly undertaking.
Step 2. Planning your time
There are hardly a few people who have handled a project that requires the same attention, effort and time as building an airplane from scratch. This activity is not for amateurs. It requires constant and measured effort over a long period of time.
In order to reduce delays along the way, and the progress on the project does not stand in one place, you can break all the work into many small tasks. Working on each task will not seem so difficult, and success will come gradually as each task is completed. On average, it will take a builder 15 to 20 hours a week to complete a simple airplane project in a reasonable amount of time.
For the avid builder, most aviation projects take two to four years to complete. On average, the construction of an aircraft can take five or even ten years. That is why experienced aircraft builders will never set an exact date for the first flight, despite the constant questioning glances of friends. As an excuse, you can say "it's not worth it" or "as soon as possible."
Idealists don't belong here
Not all builders realize the importance of proper timing. Aircraft construction is not a social undertaking, and in reality it can be lonely as hell while on the job. Sociable individuals may find this occupation more difficult than one might imagine. Therefore, everyone who is dedicated to this business should find pleasure in working alone.
The next aircraft to be built without hole mismatches will be the first ever. Robert Piercing, in his cult novel Zen and the Art of Motorcycle Maintenance, talks about drilling mistakes. These mistakes can discourage a builder from working on a project for a long time. Such errors often accompany aviation projects, and if the builder does not have the personal qualities that would push him to cope with such difficulties, the project can be closed.
Perfectionists who strive for excellence in everything should look elsewhere. If all planes had to perfectly comply with the laws of aerodynamics, hardly anyone would dare to take off. Perfectionism is often mistaken for a craft, but they are very different things. It doesn't matter how good the thing is: you can always improve something, make it brighter and better. The task is not to make the best plane - the task is to make a practical plane so that the builder would not be ashamed of it, and he would not be afraid to fly on it.
Step 3. Workshop equipment
The next important point is the construction site. Not everyone can afford to have a workshop like the Cessna hangars. Size, in fact, does not play a decisive role in this case.
Light aircraft are built in basements, trailers, shipping containers, village sheds, and adobe huts. In most cases, a double garage is sufficient. A single garage can also be sufficient if you have a dedicated storage room for wing-shaped assemblies.
Most people believe that the best place to build an airplane is in the city airport hangar. In reality, hangars are the least suitable for aircraft projects. Most often, hangars are much warmer in the summer and colder in the winter than outside. They are generally poorly lit and rarely found near your home.
Regardless of where the aircraft is being assembled, you should think about convenience. Investments in comfort, in some semblance of climate control, good lighting and a worktable of a comfortable height, rubber mats on the concrete floor, will more than pay off.
Martin and Claudia Sutter describe their experience of building an RV-6 in the living room: “In Texas, where the temperature fluctuations are always too extreme, the air conditioning system in the hangar would have cost us more than building the plane itself. We thought about working in a garage, but as it turned out, our cars could not withstand exposure to the open sun for a long time. Therefore, breakfast in the bar, accommodation in the bedroom, and construction in the living room - this is how our work was organized. Amenities include domestic air conditioning, heating and large sliding doors that allowed the plane to be rolled out. The most important thing was that everything was always at hand "
Step 4. Where can I get money for the plane?
In second place after time is the question of money. How much will it cost to build an airplane? There is no answer that fits everyone: on average, such projects cost from $ 50,000 to $ 65,000, and the real cost can be either lower or much higher. The construction of an aircraft is like a phased payment of a loan, it is important to correctly assess the entire volume of required resources, both financial and time, before the start of the active phase of investments.
Allocation of project costs begins with the definition of the tasks that the aircraft will solve. Modern aircraft manufacturers are ready to install everything that you can wish for on their products. Domestic aircraft builders, in turn, know exactly what they want. If the plane will not fly by instruments, then there is no need to put equipment for flight by instruments on it. No need to fly at night - why put on $ 1000 runway lights. A constant-pitch propeller costs three times less than a constant-speed propeller, and in most cases does not lose much to a constant-speed propeller in flight efficiency.
The correct question is where to get the money? The wealthy aunt Praskovya will not leave a will in time to finance the construction, so you will have to postpone the trip to the south, or increase your income.
Van's Air Force website owner Doug Reeves suggests the first approach. His book, Ten Steps to Getting an Airplane, includes sheltering a new car, moving away from cable TV, switching to light, healthy meals made from fruits and vegetables, and moving away from unlimited phone rates in favor of lean plans. Overall, Doug calculated that taking and following these steps saved him about $ 570 each month. He conscientiously saved this amount in a piggy bank every month and now flies an RV-6.
Bob Collins, the RV builder, took a different path (not everyone who builds an airplane builds an RV). His job as an editor for public radio supported him and his family, but it was not enough to buy an airplane. In general, he became "the oldest newspaper peddler." Seven days a week, from two to six in the afternoon, he delivered the local press. This occupation, coupled with his usual job, family life, and plans for an airplane, did not leave him much sleep, but in the end he became the proud owner of an RV-7A.
Step 5. Where to get your mind?
“I have never riveted, cooked, painted, and in general I am not a master of gold,” an inexperienced builder might argue. Am I able to build anything as complex as an airplane at all?
In reality, it is not that difficult. Home-built aircraft are common mechanical devices. Mechanical control units, simple and easy-to-understand electrician, almost no hydraulics - you can study and assemble everything yourself. A standard aircraft engine, for example, has four hoses, three cables, and two wires. Well, if the knowledge is not enough, you can always glean the missing gaps for textbooks and manuals.
The aircraft construction technique is simple and obvious. Riveting can be mastered in one day, welding is more time consuming, but fun and almost free. In everyday life, a lot of things are made of wood, the equipment and tools for woodworking are brought to perfection, and everything can be mastered via the Internet and Youtube.
If a structured presentation of material is best for you when learning new information, then you can take lessons in mastery in aircraft construction. Similar events are held by manufacturers of kit kits and some private builders.
Comprehensive support is essential
If the dream of flying your own plane does not leave you, and enthusiasm overwhelms you to the very top, then support from like-minded pilots will help speed up the work on the project.
- Above all else, it is worth enlisting the support of your family. Working hours in the workshop can be long and tiring, including for the rest of your family. Spousal and family support in such cases is simply necessary. Any aircraft projects that cross the relationship are doomed: “He spends all his time on this fucking plane. She nags me all the time about my project "- is it worth starting a project in this state of affairs. Mitch Locke adheres to a simple tactic:" Before starting to build a new plane, I go to my wife and ask her for a list of all the benefits that she wants her life to be better as long as I devote less time to her. " And it works: Mitch built seven planes on his own, while there are many projects run by family teams: parents with children, spouses. When joint teamwork brings people together, aircraft assembly becomes an additional opportunity to spend time with loved ones.
- Support outside the family circle is also important.
When choosing a solution in favor of a particular project, it is also important to take into account service support and the experience of previous builders. Is it possible to change the thickness of the ribs without compromising the safety of the structure? Will the aircraft model company be able to answer this question? How quickly will the answers come? Is there an aircraft builder forum that can help newbies?
Tips on how to speed up the work on a project - help from professionals and KIT kits
One of the reasons for the growth in the number of home aircraft builders is the emergence of KIT kits. Most aircraft in the past were built from scratch. Builders purchased a set of blueprints for the aircraft of their choice (or at their own peril and risk they designed them themselves), and then ordered materials for the manufacture of parts and assemblies.
Here are some tips for those who decide to go this route:
- You can use virtual design programs such as X-Plane: Airplane manufacturer David Rose uses this program to design his models, complementing it with the Airplane PDQ package (total cost - $ 198). The cost of the package is low, and the capabilities are at the level of industrial systems for $ 30,000.
- The structure can be designed: To do this, you can study the book by Martin Hollman "The design of a modern aircraft" (Modern Aircraft Design) or K.S. Gorbenko "We build planes ourselves."
If you are not ready to make an airplane from scratch, then it makes sense to think about buying a KIT - a set. A kit manufacturer can provide accurate and ready-to-assemble aircraft parts with significant savings in resources and materials compared to building from scratch. Assembly instructions, unlike engineering drawings, can save you countless hours of thinking about how parts fit together. Such time savings will lead to the fact that it will be in your power to assemble more complex and high-tech aircraft. Today's KIT kits cover an astoundingly wide range of models, from wood and fabric like the Piper Cub to composite models at a cost comparable to a Citation.
Here is a list of KIT kits manufacturers that aircraft builders may find helpful:
KIT - sets of Piper Cub PA-18 and its replicas
SKB "Vulkan-Avia"
CJSC "Interavia"
KIT - sets of RV aircraft
KIT - sets of aircraft C.C.C.P.
Your plane.ru
KIT - Ultra Pup aircraft kits
KIT - sets of aircraft CH-701, as well as Zenith, Zodiac and Bearhawk
Avia-Comp Company
In order to legalize flights on a home-built aircraft, you will have to go through the procedure for obtaining a certificate of a single copy of an aircraft (EEVS, in more detail).
Perhaps construction is not for everyone. If you like to work with your hands and your head, know who to contact for support, have enough funds to buy a pickup truck and have a place to store it, you should be able to make your own plane. Of course, this is not an activity for everyone, but those who do it consider this experience one of the most exciting and joyful moments in their lives.
useful links
Aircraft Construction Sites:
- www.stroimsamolet.ru
- www.reaa.ru
- www.avia-master.ru
- vk.com/club4449615 - VKontakte group with a lot of useful information
- www.avialibrary.com - library of aircraft designers
In the summer of last year, the head of the aviation club of the Vnukovo House of Culture (Moscow), amateur pilot Andrei Chernikov demonstrated rather complex aerobatics over the Razdolye airfield in the Vladimir region on a single-seat biplane designed and built by his own hands.
The aircraft does not yet have a certificate of airworthiness due to financial and organizational difficulties. However, it was built in accordance with the requirements for aircraft of this type. Today Andrey Aleksandrovich presents his plane to the readers of our site.
Before proceeding with the description of the design of the aircraft, it will be necessary to tell a little about the history of its creation. And an ultralight aircraft (ultralight or ultralight) was created in the aircraft design circle at the Vnukovo DK. The guys, as in other similar circles, built various sports models, performed (and not without success) in competitions. Mastering the basics of the theory and practice of creating aircraft, the members of the circle came up with the idea of building a real plane - albeit small, but on which it would be possible to fly into the sky.
The next step was the choice of the aircraft layout, its layout and design.
The first thing that was guided when choosing a design was its cost. It is clear that the simpler the design, the cheaper it is. But the main criterion was still reliability, and hence safety. For this purpose, they chose both a biplane scheme and a power plant with a pushing propeller. With this arrangement, the rotating propeller is protected from the front by fenders with struts and struts, and from the sides - by braces. In addition, with such an arrangement of the propeller-driven installation, nothing restricts the pilot's forward view, and the engine exhaust from the muffler is left behind. Savings were achieved by using inexpensive and non-scarce, but repeatedly tested materials, components and assemblies.
Frankly speaking, most of the work on the construction of the aircraft, fearing that the first pancake would not come out lumpy, and to speed up the process, he performed himself, in his free time from his circle duties.
The power structure of the aircraft is a flat truss, assembled mainly from duralumin pipes with a diameter of 60 mm with a wall thickness of 2 mm. Attached to this truss are wings, empennage, power plant, fuel tank, instrument panel, landing gear, seat and pilot fairing. The truss pipes are interconnected by means of lamellar pads with underlay curly radius washers, bolts with self-locking nuts.
In the places where struts or braces are connected, the tail boom of the truss is reinforced, bougie is put on it - tubular bushings with brackets.
Wings and plumage. According to its scheme, as already noted, the aircraft is a single-column biplane (in fact, there are two stands - between the upper and lower half-wings on both the right and left sides). The uprights are V-shaped, the front branch is made of oval duralumin tube, the back one is made of a round tube.
1 - fairing with windshield,
2 - upper left wing (right - mirrored),
3 - engine,
4 - propeller,
5 - keel brace (cable Ø 1.8), 6 - brace,
7 - rudder cable
9 - rudder,
11 - power set,
12 - spring of the main wheels of the chassis (steel plate);
13 - the main wheel of the chassis,
14 - left lower half-wing (mirrored right);
15 - aircraft control stick;
16 - engine control lever,
17 - front (steering and brake) wheel,
18 - brake mechanism,
19 - front wheel rack,
20 - air pressure receiver,
21 - biplane stand (2 pcs.),
22 - brace of the upper semi-wing (2 pcs),
23 - front braces (cable Ø 1.8),
24 - brace of the stabilizer and keel (D16, pipe Ø 14x1, 2 pcs),
25 - additional biplane stand (2 pcs),
26 - headlamp and aeronautical light (2 sets),
27 - aileron (2 pieces),
28 - stabilizer,
29 - elevator,
30 - plate (duralumin s0.5)
The wings, both upper and lower, are single-spar, they have the same biconvex profile РІІІА with a relative thickness of 18%. This profile, developed at TsAGI in the early 1930s, is still widely used, since it has high bearing characteristics. Technologically, the wings are divided into left and right detachable parts.
The spar has a channel-shaped section, the shelves are made of pine laths with a section of 10 × 10 mm, and the wall is made of plywood with a thickness of 1 mm.
Ribs were made from pine laths with a cross section of 8 × 4 mm. Each wing is assembled by stringing ribs onto a spar.
(parts material - duralumin):
1 - main beam (pipe Ø 60 × 2),
2 - front strut (pipe Ø 35 × 1.5),
3 - pylon for fixing the upper wing (pipe Ø 60 × 2),
4-center post (pipe Ø 60 × 2),
5-seat frame (tube Ø 30 × 2);
6 - tail boom strut (pipe Ø 35 × 1.5),
7- tail boom (pipe Ø 55 × 2);
8-long bougie (pipe Ø 60 × 2.5, 2 pcs.);
9-short bougie (pipe Ø 60 × 2.5);
10 - engine mount bracket (pipe Ø 16x 1, 2 pcs.).
All wooden parts are joined with epoxy glue. The lining of the nose of the wing is made of 1 mm plywood - together with the spar it forms a closed loop and receives the torque. The rest of the wing is sheathed with percale and covered with enamel. By the way, he also glued the percale sheathing to the wooden elements of the power set.
The upper wing, in contrast to the lower one, has ailerons and a slightly larger span. Ailerons have the same single-spar design as the wing. The ribs are arranged in a zigzag manner, and the profile is symmetrical.
The upper half-wings with an angle of installation of 4 ° are mounted on the pylon of the central pillar without a transverse V The gap between them is closed with a duralumin strip. Additionally, each upper half-wing is attached to the main girder of the truss by a brace and a cable brace.
1-front wheel (steered, brake, Ø 280, b90, from the card),
2- front wheel stand,
3 - fairing (fiberglass),
4 - air pressure receiver,
5 - dashboard,
6 - aircraft control stick,
7 - windshield;
8 - seat frame,
9- front brace,
10- engine mount bracket (duralumin pipe Ø 16 × 1),
11 - pylon for attaching the upper wing,
12 - motor frame,
13- engine Rotaх 582, N = 64 hp,
14 - radiator,
15 - screw shaft,
16 - electronic unit,
17 - muffler,
18 - central rack,
19-rechargeable battery,
20- fuel tank V = 20 l (aluminum canister),
21 - tail boom,
22 - spring of the main wheels,
23 - main wheel (Ø 280, b90, from the card, 2 pcs),
24-seat,
25 - fastening belts (automobile),
26 - tool box,
27- engine control lever,
28- brake mechanism.
The lower semi-wings are docked to the main truss beam with a transverse V = 4.5 °. The installation angle of the lower wing is also 4.5 °.
The horizontal tail (GO) consists of a stabilizer and an elevator.
The vertical tail (VO) includes the keel and rudder (RN) The rudder is one-piece with a knife deflected on the ground. The keel and stabilizer are interconnected by brackets and struts, and the upper ends of the struts with inter-wing struts are cable braces.
1 - the engine control lever,
2 - toggle switch for turning on the headlights,
3 - generator 1 filling station,
4-light generator failure 2,
5 - generator failure lamp 1,
6-ignition switch of the 1st circuit,
7 - variometer (indicator of the speed of ascent and descent),
8 - ignition switch of the 2nd circuit,
9-horizontal speed indicator,
10 - accelerometer,
11 - warning lamp about engine faults,
12 - slide indicator,
13 - a complex device for monitoring the operation of the engine,
14-altimeter,
16 - cigarette lighter socket,
17 - fuel gauge,
18 - power switch,
19 - rudder and front wheel control pedals (2 pcs.),
20 - starter gas station,
21 - generator 2 filling station,
22 - toggle switch for turning on the beacon and signal lights,
23-aircraft control stick,
24-button engine start,
25 - toggle switch for turning on the lighting of devices,
26 - brake lever.
The power set of the keel and stabilizer is similar to that used in the wings, and at the rudders and elevators - as in the ailerons with a zigzag arrangement of ribs. The profile of all elements of the tail unit is symmetrical TsAGI-683. The lining of the toe is made of millimeter plywood, and behind the spar is linen (percale). The coating is also enamel.
Power point
At first, the plane was equipped with a two-cylinder engine RMZ-640 with a capacity of 32 hp. from the snowmobile "Buran" and a two-blade pushing monoblock propeller with a diameter of 1600 mm of constant pitch. And with such an installation, the plane flew well for many years and was confidently controlled. But one day I found out that a relatively inexpensive two-stroke liquid-cooled Rotax 582 engine was being sold. It turned out that the engine was disassembled: the owners wanted to repair it, but then they could not assemble it. So I bought it "in bulk", and then assembled it, eliminating the malfunctions along the way.
Upper right half wing (left - mirrored):
1 - spout plating (plywood s1),
2 - spar,
3 - covering the plane (percale impregnated with enamel),
4 - rib,
5 - aileron control cable fairing (4 pcs),
6 - incomplete rib,
7 - ending,
8 - trim of the aileron nose (plywood s1),
9 - kronipeyn-hitch of the aileron (2 pieces),
10 - covering the aileron (percale, impregnated with enamel),
11 - end aileron rib (root - mirrored),
12 - oblique rib of the aileron,
13- trailing edge of the aileron,
14 - knit of the aileron,
15 - the trailing edge of the wing,
16 - arm of the wing,
17 - root rib,
18 - attachment point for the semi-wing to the pylon bracket (2 pcs.),
19 - an inter-wing rack mounting bracket,
20 - "wall" - additional spar,
21-spar aileron,
22 - aileron control rocker,
23 - aileron swing axis (2 pcs.),
24 - visor,
25 - aileron control wiring (cable Ø 1.5, 2 pcs.).
In terms of dimensions, weight, volume of two Rotax cylinders, it is about the same as that of the RMZ-640, but its power is almost twice as high (there is even a version that the second engine is not a very successful copy of the first). In addition, Rotax has a dual-circuit ignition system (two candles per cylinder) and liquid-cooled cylinders. The fuel is not in short supply - AI-95 gasoline mixed with engine oil in a ratio of 50: 1.
(unspecified material of item parts - duralumin):
1 -central post (pipe Ø 60 × 2),
2 - plate for attaching the pylon to the main post (sheet s4, 2 pcs.),
3 - bracket for attaching the front strut (stainless steel, sheet s2.5),
4 - radius washers,
5 - aileron rocking,
6- aileron rocker arm,
7 - pylon (pipe Ø 60 × 2),
8 - brackets for attaching the upper wing console (4 pcs.),
9 - fastening brackets to power elements (bolt М12, 2 pcs.),
10-fastening of plates to load-bearing elements (bolt М8, 3 pcs.).
And if, when replacing the engines, it was almost not necessary to redo the attachment points, then a new screw had to be purchased: with a diameter of 1680 mm, also pushing, but three-bladed, with an adjustable step on the ground. A reduction gear with a gear ratio of 3.47 is combined with the engine and provides the propeller with up to 1900 rpm.
With the new propeller-driven installation, the aircraft also acquired higher flight characteristics, and became capable of performing rather complex aerobatics.
(a - profile, b - rib, c - root rib and tip):
1 - rib nose (pine lath of variable cross-section),
2 - a rack of a spar opening (pine lath 8 × 4, 2 pcs.),
3 - brace (pine lath 8 × 4),
4 - knit (plywood s1),
5 - the upper bow of the rib (pine lath 8 × 4),
6 - end knit (plywood s1),
7 - lower bow (pine lath 8 × 4),
8 - sidewall (plywood s6),
9 - upper bow (gluing of two pine slats 12 × 6),
10 - nose of the root rib (pine insert with variable section),
11 - lower bow (gluing of two pine slats 12 × 6).
The fuel supply is small - only 20 liters. after all, the plane is designed for training near aerodrome flights, but this fuel is enough for an hour and a half. Fuel is poured into an aluminum can, which is attached to the platform behind the driver's seat.
Aircraft landing gear - tricycle with a front steerable wheel. Damping is carried out by a rubber cord 8 mm in diameter, looped over the pendulum cross member. The ends of the cord are connected and secured to the upper transverse post.
1 - sheathing (plywood s1),
2-root rib (plywood s6),
3 - rack bracket (s2 stainless steel),
4 - bracket boss (plywood, s10),
5 - boss of the semi-wing attachment point (s12 plywood, 2 pcs),
6 - plate (duralumin 2, 4 pcs.),
7 - bushing (tube Ø 8 × 0.5, 2 pcs.).
The front wheel is controlled by pedals through flexible (cable) wiring. The braking mechanism is also mounted on the same wheel, which is activated by a lever mounted on the aircraft control handle. The rear main support wheels are mounted on a transverse spring made of steel strip.
All wheels are the same, with an outer tire diameter of 280 mm and a width of 90 mm. They are used from the map. The track of the rear wheels is 1150 mm, and the base (the distance between the axles of the front and rear wheels) is 1520 mm.
1 - trim of the stabilizer nose (plywood s1),
2 - covering the stabilizer (percale),
3 - trim of the elevator nose,
4-covered elevator (percale),
5 - the front part of the stabilizer rib (plywood s1),
6-spar stabilizer,
7- stabilizer rib,
8 - stabilizer wall,
9 - hinged stabilizer bracket (2 pcs),
10 - the axis of the hinge of the elevator suspension (Zsht),
11-elevator suspension bracket (2 pcs),
12 - the front part of the elevator rib,
13 - rib of the elevator,
14 - rear edge of the elevator.
A heel is provided to protect the tail boom from damage when it touches the ground.
From the very beginning, the aircraft was conceived without a cockpit - only in this case, you can fully feel the flight and feel the car.However, later it was still equipped with a homemade fiberglass nose fairing with a bottom and a transparent visor of a 5-mm plexiglass sheet.
2 - rudder,
3 - rocking chair (D16, sheet sЗ),
4 - bracket for attaching the keel to the stabilizer (4 pcs.),
5 - hinge of the rudder hinge (2 pcs),
6 - eyelet of the hinge hinge of the rudder (duralumin, sheet sЗ, 2 pcs),
7 - rudder hinge eyelet (stainless steel sheet s1, 2 pcs),
8 - bushing (stainless steel, pipe Ø 6 × 0.5, 2 pcs),
9- bracket for fastening braces (2 pcs).
The seat is also homemade. It is based on nylon belts sewn to the inclined frame, which serves as an additional strut of the central post. A foam pillow and a back are laid on the base, covered with a dense fabric - avisent. Seat belts are car seat belts.
(details of positions I, 2, 7, 11, 15, 17 are made of steel pipe 20x20x1.5):
1 - fork stand,
2 - the upper cross member of the fork,
3 - drum of a rubber harness (pipe Ø 10 × 1, 2 pcs.),
4 - a roller of a rubber band (circle 8.2 pcs),
5 - bushing of the support pillar axle (pipe Ø 12 × 2, 2 pcs.),
6 - shock absorber (rubber cord Ø 8, 4 pcs),
7 - the lower cross member of the fork,
8 - cross member of the two-arm lever (pipe Ø 20 × 2),
9 - bandage (nylon threads),
10 - axle eyelet (steel sheet s2, 4 pcs),
11 - rack reinforcement (2 pcs),
12 - eye bolt for fastening the control wiring (2 pcs),
13 - stop (rubber 2pcs),
14 - stop fastening (bolt M4, 2pcs),
15 - the upper knee of the two-armed lever (2 pieces),
16 - gusset (steel sheet s2, 4 pcs),
17 - the lower knee of the two-armed lever (2 pcs),
18 - wheel axle bushing (2 pcs),
19 - axle of a two-armed lever (roller Ø 8 with a washer and a cotter pin, 2 sets),
20 - bushing of the axle of the two-armed lever (2 pcs),
21 - the axis of the rack.
The aircraft control system is a cable with intermediate rods from the control stick (RSS) located on the farm in front of the pilot. Engine control is a lever mounted to the left of the pilot. The deflection of the rudder and the turn of the front wheel on the taxiing are by pedals. The aircraft is equipped with the necessary instruments that ensure flight in simple meteorological conditions (PMU), which control the operation of the engine. All of them are located on the dashboard in front of the pilot. There are headlights on the upper wing, and on the tail there are also navigation lights. As for the flight characteristics of the aircraft, some of them are given in the table, while others, such as the rate of climb, maximum flight altitude, have not yet been measured.
1 - rack,
2 - the main beam,
3 - bougie (D16T, pipe Ø80 × 10),
4 - rack axis (M10 bolt with castellated nut and washer),
5- upper support bush (bronze),
6 - lower support sleeve (bronze),
7 - cable Ø 1.8,
9 - pedal,
10 - lever,
11- rocking chair,
12 - the axis of the lever and rocking chair,
13 - the tip of the lever,
14-axis tip of the lever and rod,
16 - thunder,
17 - rack earring,
18- eye bolt,
19-axis thrust,
20- rod and rocker mounting bracket,
21 - rocking axis,
22-rocking earring,
23 - roller with cotter pin (4 sets),
24 - cable termination.
A considerable advantage of the design is that it is collapsible. For transportation (or storage) the aircraft is disassembled into several parts: the half-wings, the tail boom, and the tail boom are disconnected from the air module. The tail unit is transported on the roof rack of the car, and the rest of the parts are transported in a two-wheeled trailer for a passenger car, fixed on a special platform. The structure is stored together with the trailer in an ordinary car garage, and is assembled in the field in less than an hour by one person.
Airplane control scheme (rudder, b - elevator, c - airlons).
From the editor. The editors warn that flights on homemade aircraft are allowed only with the appropriate certificate and pilot's license.
You have decided to build an airplane. And immediately before you the first problem - what should he be? Single or double? Most often it depends on the power of the available engine, the availability of the necessary materials and tools, as well as the size of the "hangar" for the construction and storage of the aircraft. And in most cases, the designer has to opt for a single-seat training aircraft.
According to statistics, this class of aircraft is the most massive and popular among amateur designers. For such machines, a wide variety of schemes, types of structures and engines are used. Equally common are biplanes, monoplanes with low and high wings, single and twin engines, with pulling and pushing propellers, etc.
The proposed series of articles contains an analysis of the advantages and disadvantages of the main aerodynamic schemes of aircraft and their design solutions, which will allow readers to independently assess the strengths and weaknesses of various amateur designs, help to choose the best one and the most suitable for construction.
AIRCRAFT - ONE TO ONE
One of the most common amateur single-seat aircraft designs is a strut-braced monoplane with a high wing and a pulling propeller. It should be noted that this scheme appeared in the 1920s and has practically not changed over the entire period of its existence, becoming one of the most studied, tested and constructively worked out. Typical features of this type of aircraft are a wooden two-spar wing, a steel welded truss fuselage, linen sheathing, a pyramidal landing gear and a closed cockpit with an automobile-type door.
In the 1920s - 1930s, a variety of this scheme became widespread - an airplane of the "parasol" type (from French parasol - an umbrella from the sun), which was a high-wing aircraft with a wing attached to struts and struts above the fuselage. "Parasols" are still found in amateur aircraft construction, but they are usually structurally complex, less aerodynamically perfect and less convenient in operation than classic high-wing aircraft. In addition, such devices (especially small sizes) have very difficult access to the cab and, as a result, the complexity of its emergency escape.
Single-seat high-wing aircraft:
Engine - LK-2 30 hp. designed by L. Komarov, wing area - 7.8 m2, wing profile - ClarkU, takeoff weight - 220 kg (pilot - 85 kg, power plant - 32.2 kg, fuselage - 27 kg, landing gear with skis - 10.5 kg , horizontal tail - 5.75 kg, wing with struts - 33 kg), maximum speed - 130 km / h, flight range with a fuel supply of 10 l-180-200 km
Engine - "Zündapp" with a capacity of 50 hp, wing area - 9.43 m2, takeoff weight - 380 kg, empty weight - 260 kg, maximum speed -150 km / h, rate of climb at the ground - 2.6 m / s , flight duration -8 h, stall speed - 70 km / h
The advantages of high-wing aircraft include the simplicity of the piloting technique, especially if the specific load on the wing does not exceed 30 - 40 kg / m2. High-wing aircraft are distinguished by good stability, excellent take-off and landing characteristics, they allow rear alignment up to 35 -40% of the average aerodynamic chord (MAX). From the cockpit of such a device, the pilot is provided with an optimal downward view. In short, for those who are building their first aircraft, and besides, they are going to master its piloting on their own, there is no better scheme to come up with.
In our country, amateur aircraft designers have repeatedly turned to the strut-braced vysokoplane scheme. So, at one time, a whole squadron of "parasol" aircraft appeared: "Kid" from Chelyabinsk, created by the former pilot L. Komarov, "Leningradets" from St. Petersburg, built by a group of model airplanes headed by V. Tatsiturnov, a high-wing aircraft designed by mechanic B .Frolov from the village of Donino near Moscow.
The last device should be described in more detail. Having thoroughly studied the simplest strut-braced vysokoplane scheme, the designer carefully planned his work. The wing was made of pine and plywood, the fuselage was welded from steel pipes and these elements of the aircraft were covered with canvas according to classical aviation technology. I picked up large wheels for the chassis so that you could fly from unprepared unpaved areas. The power unit is based on a 32-horsepower MT-8 engine equipped with a gearbox and a large-diameter propeller. Takeoff weight of the aircraft - 270 kg, flight balance - 30% MAR, specific wing loading - 28 kg / m2, wingspan - 8000 mm, propeller thrust in place - 85 kgf, maximum speed - 130 km / h, landing - 50 km / h
Test pilot V. Zabolotsky, who flew over this apparatus, was delighted with its capabilities. According to the pilot, even a child can control it. The aircraft was operated by V. Frolov for more than ten years and participated in several rallies of the ultralight aircraft.
No less delight among the test pilots was caused by the PMK-3 aircraft, created in the city of Zhukovsky near Moscow by a group of amateur aircraft designers under the leadership of N. Prokopets. The vehicle had a peculiar nose part of the fuselage, a very low landing gear and was designed according to a high-wing strut-braced aircraft with a closed cockpit; a door was provided on the left side of the fuselage. The wing is slightly sloped back to provide the necessary centering. Aircraft construction - all-wood, covered with canvas. The wing is single-spar, with pine shelves, a set of ribs and the forehead of the wing are sheathed with plywood.
Wing area - 10.4 m2, wing profile - R-Sh, take-off weight - 200 kg, fuel reserve - 13 liters, flight balance - 27% MAR, static propeller thrust - 60 kgf, stall speed - 40 km / h, maximum speed - 100 km / h, flight range - 100 km
The base of the fuselage is three spars, and therefore the fuselage had a triangular cross-section. The empennage and control system of the PMK-3 aircraft are made as in the famous training glider B. Oshkinis BRO-11 M. The basis of the power plant is a 30-strong outboard boat motor "Whirlwind" with liquid cooling; while the radiator protruded slightly from the starboard side of the fuselage.
An interesting version of the strut-braced vysokoplane of amateur construction was the "Don Quixote", developed in Poland by J. Janowski. With the light hand of the amateur aircraft construction enthusiast, the famous test glider pilot and journalist G.S. Malinovsky, who published the drawings of Don Quixote in the magazine "Modelist-Constructor", this, in general, not entirely successful scheme became very widespread in our country - at the rallies of the ALS there were sometimes more than four dozen similar devices. Professional aircraft designers, however, believe that amateur aviators in this scheme were attracted primarily by the unusual appearance of the aircraft, but it was in it that some "pitfalls" were hidden.
A characteristic feature of Don Quixote was the forward-facing cockpit, which provided excellent visibility and comfortable seating for the pilot. However, on an extremely light aircraft weighing up to 300 kg, the CG changed significantly when a more slender one, weighing 60 kg, sat in the cockpit instead of an 80-kg pilot - the device suddenly turned from overly stable to absolutely unstable. Avoid such a situation even when designing the machine - it was only necessary to install the pilot's seat in the center of its gravity.
Aircraft with a pusher propeller, designed according to the Don Quixote aircraft scheme:
Engine power - 25 HP, wing area - 7.5 m2, empty weight - 150 kg, takeoff weight - 270 kg, maximum speed - 130 km / h, rate of climb at the ground - 2.5 m / s, ceiling - 3000 m, flight range - 250 km. Machine construction - solid wood
Engine power - 30 HP, wingspan - 7 m, wing area - 7 m2, empty weight - 105 kg, takeoff weight - 235 kg, maximum speed - 160 km / h, rate of climb - 3 m / s, flight duration - 3 h
Construction - fiberglass, engine power - 35 hp, wingspan - 8 m, wing area - 8 m2, wing profile - Clarke YH, takeoff weight - 246 kg, empty weight - 143 kg, flight balance - 20% MAR, maximum speed - 130 km / h
Another feature of Don Quixote is the tailwheel landing gear. As you know, such a scheme, in principle, does not provide the directional stability of a light aircraft when it moves along the airfield. The fact is that the movements of the aircraft with a decrease in its mass and moments of inertia become fast, abrupt, short-period, and the pilot has to concentrate all his attention on maintaining the direction of the takeoff or run.
The A-12 aircraft from the Aeroprakt club (Samara), which was one of the copies of Don Quixote, had exactly the same congenital defect as the firstborn of this constellation, however, the designers after testing the machine by professional pilots V. Makagonov and M Molchanyuk quickly found an error in the design. Replacing the tail wheel with the nose wheel for the A-12, they completely eliminated one of the main drawbacks of the aircraft of the Polish scheme.
Another significant drawback of Don Quixote is the use of a pushing propeller, shaded in flight by the cockpit and wing. At the same time, the efficiency of the propeller dropped sharply, and the wing, which was not blown by the air flow from the propeller, did not provide the design lift. As a result, the takeoff and landing speeds increased, which led to a lengthening of the takeoff and run, and also reduced the rate of climb. With a low thrust-to-weight ratio, the plane could not get off the ground at all. This is exactly what happened at one of the rallies of the ULM aircraft with the Elf aircraft, built according to the Don Quixote scheme by the students and staff of the Moscow Aviation Institute.
Of course, it is not at all forbidden to build vehicles with a pushing propeller, but the necessity and feasibility of creating an aircraft with such a power plant in each specific case should be carefully evaluated, since in this case, losses of thrust and wing lift are inevitable.
It should be noted that the designers who creatively approached the use of a power plant with a pushing propeller managed to overcome the disadvantages of such a scheme and create very interesting options. In particular, a machine operator from the city of Dneprodzerzhinsk P. Atyomov built several successful machines according to the "Don Quixote" scheme.
Wing area - 8 m2, takeoff weight - 215 kg, maximum speed - 150 km / h, stall speed - 60 km / h, rate of climb at the ground - 1.5 m / s, range of operational overloads - from +6 to -4
1 - metal toe of the wing; 2 - tubular wing spar; 3 - flap; 4 - tubular spars of the aileron and flap; 5 - aileron; 6 - engine control handle; 7 - cockpit entrance door (right); 8 - engine; 9 - aileron control thrust; 10 - brace in the plane of the wing; 11 - riveted duralumin fuselage beam; 12 - tubular spars; 13 - speed indicator; 14 - ignition switch; 15 - altimeter; 16 - variometer; 17 - sliding indicator; 18 - cylinder head temperature indicator; 19 - flap control knob; 20 - back parachute
A well-flying aircraft with a pusher propeller was created by a team of amateur aircraft designers from the Polet club of the Samara Aviation Plant under the leadership of P. Apmurzin - this machine was named Crystal. Test pilot V. Gorbunov, who flew over it, was not stingy with a high assessment - according to his reviews, the car had good stability, was light and easy to control. The Samarans managed to ensure high efficiency of the flaps, which were deflected by 20 ° during takeoff and 60 ° during landing. True, the rate of climb of this aircraft was only 1.5 m / s due to the shading of the pushing propeller by the wide cockpit. Nevertheless, the named parameter turned out to be quite sufficient for an amateur design - and this despite the fact that its take-off was somewhat difficult.
The attractive appearance of "Kristall" is combined with the excellent production performance of the all-metal monoplane. The fuselage of the airframe is a duralumin beam riveted from 1 mm D16T sheets. The load-bearing set of the beam also included several walls and frames curved from sheet duralumin.
It should be noted that in amateur structures, instead of metal, it is quite possible to use plywood, pine blocks, plastics and other available materials.
In the bend of the fuselage beam, in its bow, there was a cockpit, closed with a large transparent faceted lantern and a light fairing made of sheet D16T with a thickness of 0.5 mm.
The strut wing is of an original single-spar design with a 90x1.5 mm duralumin tube spar that absorbed the loads from bending and torsion of the wing. A set of ribs made of 0.5 mm D16T, stamped into rubber, were riveted to the side member. The wing brace is made of 50x1 duralumin pipe and refined with a D16T fairing. In principle, duralumin spars and struts can be replaced with wooden box-section spars.
The wing was equipped with ailerons and flaps with a mechanical manual drive. Wing profile - R-III. The aileron and flap had spars made of duralumin pipes with a diameter of 30x1 mm. Wing forehead - made of 0.5 mm sheet D16T. The wing surfaces were covered with canvas.
Plumage - cantilever. The keel, stabilizer, rudder and elevator are also single-spars, with spars made of D16T pipes with a diameter of 50x1.5 mm. The plumage was covered with a canvas. The wiring for the aileron control had rigid rods and rockers, the wiring to the rudders was cable.
Chassis - tricycle, with a steerable nose wheel. The landing gear on the aircraft was depreciated due to the elasticity of pneumatic wheels with dimensions of 255x110 mm.
The basis of the aircraft's power plant is a 35-horsepower two-cylinder RMZ-640 engine from the Buran snowmobile. The propeller is of wooden construction.
When comparing pulling and pushing propellers, it should be borne in mind that for vehicles with low power plant power, the former is more effective, which was once excellently demonstrated by the French aircraft designer at Aerospatial Michel Colomban, the creator of the small and very elegant airplane Cri-Cree "(Cricket).
It will not be superfluous to recall that the creation of small-sized aircraft with motors of minimum power at all times attracted both amateurs and professionals. Thus, the designer of large aircraft O.K. Antonov, who has already built the flying giant An-22 "Antey" with a take-off weight of 225 tons, in his book "Ten Times First" told about his old dream - a baby airplane with a 16 hp engine. Unfortunately, Oleg Konstantinovich did not have time to create such an apparatus ...
Designing a compact aircraft is not as easy as it might seem at first glance. Many conceived it as an ultralight vehicle with extremely low wing loading. As a result, ultralight vehicles were obtained, capable of flying only in the complete absence of wind.
Later, the designers came up with the idea of using wings of a small area and with a high specific load for such devices, which made it possible to significantly reduce the size of the machine and improve its aerodynamic quality.
Twin-engine low-wing aircraft:
B - plane "Pasia" by Edward Magransky (Poland) - a good example of the creative development of the "Kri-Kri" scheme:
Power plant - two KFM-107E engines with a total power of 50 hp, wing area - 3.5 m2, wing extension - 14.4, empty weight - 180 kg; takeoff weight - 310 kg; maximum speed - 260 km / h; stall speed - 105 km / h; flight range - 1000 km
1 - receiving air pressure of the speed indicator; 2 - duralumin propeller (maximum rotation speed - 1000 rpm); 3 - Rowena engine (working volume of the cylinder 137 cm3, power 8 HP, weight 6.5 kg); 4 - resonant exhaust pipe; 5 - membrane carburetor; 6 - fuel intakes - flexible hoses with weights at the ends (one per engine); 7 - gas sector (left side); 8 - handle of the trim effect mechanism (readjustment of the spring loaded elevator); 9 - dumped part of the lantern; 10 - unsupported rocker in the rudder control cable; 11 - rigid stabilizer control wiring; 12 - cable routing of the rudder drive; 13 - all-moving horizontal tail; 14 - rudder rocker; 15 - keel spar; 16 - landing gear at crimped depreciation position; 17 - spring of the main chassis; 18 - fuel tank drain pipe; 19 - control knob for hooking aileron-flaps (left side); 20 - a fuel tank with a capacity of 32 liters; 21 - cable wiring for the control of the nose landing gear; 22 - adjustable pedals; 23 - pedal loader (rubber shock absorber); 24-rubber shock absorber right landing gear; 25 - engine installation frame (steel V-shaped tube); 26 - bow strut control rocker; 27 - wing spar; 28 - hovering aileron (deflection angles from -15 ° to + 8 °, hovering - + 30 °; 29 - foam frame; 30 - wing skin; 31 - hanging aileron hinge bracket; 32 - foam ribs; 33 - stabilizer tip (balsa ); 34 - stabilizer spar; 35 - aileron toe (sheathing - duralumin, filler - foam)
Blueprints of a radio-controlled model airplane biplane (seaplane)
Read also: DIY snowmobile: and
I attached the tail booms with glue to the ribs of the central section of the wing. Cut off the ailerons from the outer sections. I glued flexible strips from a computer diskette into the wing in the places where the ailerons were suspended. They will function as hinges (photo 8). The tail surfaces were also reinforced with carbon rods.
Before assembling the model, I tried on the upper wing to the lower one and the details of the tail unit.
The tail booms are glued to both wings (upper and lower). I combined the wings with the beams using 4 struts. The tail unit was assembled separately on glue. When the wings were glued together, I attached a tail to them.
The control servos were mounted traditionally. I cut a hole in the foam for the servo and glued rectangles from pieces of a ruler with dimensions of approximately 7 × 15 mm, having previously drilled holes 01 mm in them for screws. After waiting for the glue to dry, I screwed the servo-machine with the screws that are included in its kit (photo 10).
I cut out the blanks for the hinges of the drive rocking chairs with a clerical knife from a ruler. Between the 5 × 10 mm rectangles, I inserted a 5 × 5 mm square and glued this package with Moment superglue. I rounded off the upper part of the workpiece on the skin, and then drilled a hole in it (photo 11). I glued the finished loop to the aileron (photo 12).
The thrust from a carbon strip with a cross section of 3 × 1 mm, connecting the ailerons of both wings, was fixed in the loop with a piece of a bar (from the same carbon) (photo 13). Then I started adjusting the dimensions of the rods, since the lower and upper wings have different lateral angles. Also, two rudders were connected (photo 14).
Since the carbon is cracking and it is difficult to drill it, the idea arose to make the rods from an ordinary Soviet wooden ruler, and to make the axles from a paper clip.
The model would have turned out to be a little heavier, but with an overestimated power-to-weight ratio of the model, such an increase in weight would be justified.
Two rudders are connected by a similar thrust (photo 15). The spacers between the wings and the articulated rods that connect the ailerons are clearly visible in the photo of the model from the side.
I covered the lower part of the fuselage with yacht varnish and left the entire assembly to dry for a day.
Making the thrust of the biplane-seaplane
Tips for carbon rods were bent from 01 mm steel wire (you can buy such a wire in Moscow at the E-Fly store. Of course, you can also make them from a paper clip.
He bent the wire with pliers (photo 16). trying to keep the step height about 5 mm. I bit off the tip with side cutters (photo 17). I screwed the tip to the carbon rod (rod 01.5 mm) with a thread (photo 18). The connection was impregnated with Titan glue.
First, I installed the rod on the "hog" of the steering wheel, then I put the servo rocking chair on it and then fixed it on the drive axis.
Installing the engine on a model airplane
The engine was based on a line segment. For attaching the model engine flange to it, I was looking for microscrews for a long time, but then I decided to glue it with cyacrine glue (photo 19, 20). I tried to tear off the flange after fastening - it was not possible.
The frame with the pre-assembled 2730 engine looks pretty good.
I put the power unit in its place. Photo 21 shows the location of the servos, they control the rudders and elevators.
Making floats
Since it was decided to assemble a seaplane, it was required to make floats for it. By the way, they can also serve as skis for takeoff and landing of the model in winter.
I chose the width of the floats at 30 mm, and the height - 40 mm. Collected them in one sitting. I glued the patterns with a box. But with dimensions, it seems, he missed. Subsequently, it turned out that the biplane did not want to take off from the fresh loose snow.
The float skis needed to be made wider and longer. The bent float runner had to be glued under the load. I painted the floats with acrylic paint. Then he covered them with two layers of domestic-made Bor yacht varnish.
I was hoping to just glue the floats to the bottom of the tail booms, but it seemed that such a mount would be unreliable. I had to glue another rib under each float. Now each of them rests in two places: one on the tail boom, and the other on a rib from a single ceiling (photo 22).
The Korona receiver, which has 4 channels in the 35 MHz range, is installed in the fuselage.
I held the antenna under the tail, initially leading it under the wing and passing it along the tail beam. (photo 23).
The fuselage was originally designed taking into account the placement of a battery with a capacity of 8 610 mAh. But it's good that it turned out to be wider, and the larger 750 mAh and 1000 mAh batteries fell into his head (photo 24). In practice, they did not even need to be additionally secured.
The control weighing showed that the flight weight of the model (with a battery with a capacity of 750 mAh and a voltage of 11.4 V) was 340 g.
The flyby of the model took place on Saturday, mid-March. The ice on the pond turned out to be strong and had not yet begun to melt, although the temperature was already above zero - +2 C. Most of all, it was disturbing that the breeze was three meters per second. Therefore, in order to carry out a vertical takeoff, it was necessary to guess the moment when the wind died down.
A couple of times the model before the start filled him up with gusts.
I was afraid to lift the seaplane myself. Mainly because I wanted to objectively assess how it flies and whether it is generally suitable for flying. An experienced pilot was needed, able to determine the flying qualities of the model.
The tests were carried out by an experienced modeler and pilot Konstantin Ivanishchev (photo 26). First, he launched from his hand, then - from the trampled path, and only then - vertically.
After conducting several flight tests on a 750 mAh battery, we changed it to a more capacious (1000 mAh) and heavy one. The centering has been corrected somewhat, because its center has moved to the edge of the wing in front.
The tests continued until the accident: the float broke and the nose was torn off.
As in large aviation, the “human factor” played a fatal role.
The damage to the seaplane was minor. They were eliminated in a matter of minutes.
In order for the reader to receive an objective conclusion on the results of the flights, I will give the assessment of the tester.
Impressions of this RC model
Yuri's radio-controlled models are always very unusual. Even the appearance of his new model was unlike any other.
The biplane-hydroplane turned out to be just wonderful: it flew confidently.
After I got used to his reaction to the controls, I began to try takeoff and landing on the snow.
Despite the looseness of the snow, all the runners' floats confidently held this radio-controlled model aircraft on it. It turned out to be possible and vertical takeoff, which allows you to launch the model from any platform.
The seaplane is stable in the air, the large angle of the transverse "V" of its planes provides control only with the help of elevators and rudders.
The motor of the biplane model even has excessive power. In principle, you can perfectly “fly” at a third of its power. If you increase it to two-thirds, then the flutter of the screw begins, which can be corrected by installing another type of screw - for example, DD.
The model is so stable in flight and obedient to the rudders that it can be a “desk” for novice model airplane builders.
Diy radio-controlled seaplane - detailed photo of manufacturing
Equipping the radio-controlled model