This is the ANT-25 (RD) aircraft, the airplane that was intended for achieving the world record in flight range. It was designed as single motor monoplane with very large value of wing aspect ratio. A crew of three was housed in closed cabins. ANT-25 RD had performed its first flight at June 22, 1934 and it was equipped with M-34 motor. M-34R motor in 900 hp power was installed on second ANT-25 later.
Valery Chkalov's crew had performed several record spans on ANT-25/M-34R airplane (registry number N-025-1). Most famous of them was the flight from Moscow to United States over North Pole. ANT-25 had taken off from aerodrome near Moscow (now it is known as "Chkalovskiy") at July 18, 1937 and it had overcome the distance in 9130 kilometers. Even more impressive flight was performed by Mikhail Gromov's crew on anoter ANT-25. Taking off from aerodrome near Moscow at July 12, 1937, the crew of Gromov, Yumashev and Danilin had landed in San-Jacinto, California after 62 hours and 17 minutes. Significant amount of fuel was still available in ANT-25 tanks, but Mikhail Gromov was "stopped" by borderline between USA and Mexico. The fact is that agreement on flight of Soviet aircraft was not obtained because nobody was able to imagine that ANT-25 may reach Mexico!
Enhanced release of ANT-25 was run into production as long-range bomber. About 20 airplanes were constructed in the spring of 1936. However the entire order for 50 aircrafts was not completed. These machines were flying with various motors and they were used primarily for testing purposes.
(taken from here: http://aviadejavu.ru/Site/Crafts/Craft19923.htm )
The new contest "The world aviation before 1939" was started on model website http://rc-aviation.ru/ , and initially I had chosen experimental Lockheed XJO-3 for construction,
Экспериментальный Lockheed XJO-3 1938 года на конкурс "модель до 250 граммов"+113
3 мар. 2016 г., 13:52:47 | Алексей Колюбаев Долгопрудный
but fair criticism was raised on the forum (because all participants had chosen foreign machines) - "Why nobody has Russian airplans?" Therefore I was scratching my head one day and nevertheless I had decided to build this perfect machine.
So I decided what I will have: wingspan - 1500 mm, length - 624 mm. The wing is sectional and dismountable.
Total weight - 524 grams.
Basic materials: Styrofoam ceiling tiles, wooden rulers and balsa.
The motor: Eurgle RC Plane 1580kv D2810 Brushless Outrunner Back Mounting Motor (300W)
ESC: 30 amps
Servos: HXT900 Micro Servo 1.6kg / 0.12sec / 9g
Receiver: FrSky D8R-II PLUS 2.4Ghz 8CH Receiver with Telemetery
Battery: nova power 2s1p 800mAh 7,4V max 60c
Having studied the experience of our and foreign colleagues I have decided to avoid repeation of their mistakes. Their ANT-s were falling approximatelly equally and consequently I had applying small wing twist (0 degrees at wing ends). The nose part is increased and tail part is also increased but not so much:
The elevator is also increased in size:
During 3D editing of ANT-25 model (ant-25.skp) I tried to choose the degree of change so that 100% recognition was not lost. Hopefully I have been able to achieve this.
The fuselage is made from 3 mm balsa frames and two 50 cm wooden rulers:
The rudder is made from two layers of Styrofoam ceiling tile:
The elevator is also made from Styrofoam tile, no longerone was implemented:
I had decided to make dismountable wing. The center wing section has "pensil box" (rulers) for guide bars of side wing consoles, bamboo skewers for shashlik-kebab (they are fixed by thermo glue) and three ribs covered by 1 mm balsa. Magnets were dismounted afterwards:
This is trying-on of incomplete wing:
Left and right consoles: longerone and ribs are made from ruler. Wing twist is setup by underlaying some wooden sticks from ice-cream and ruler:
Then I had sheathed wing by Styrofoam tile and installed servos:
Ailerons are hanged on pin hinges:
Now it's time to swift fuselage by vellum paper on glue:
Servos and motor are installed on [frames] reinforced by one layer of balsa:
And now fuselage is covered over servos:
I made nose hood from few layers of Styrofoam tile:
I had ground excess material by Engraving machine (Dremel):
I have had quite a job with side walls of hood, I was obliged to use money elastic bands:
While the hood dried, I had made chassis from 2 mm steel push rod, at the same time I had used metal bingers for wing consoles fixing:
Here I had sticked the bottom of hood:
This is the hood cover fron 4 layers of Styrofoam tile:
... and here you may see holes for weight reduction:
Now it's time for ESD placing:
I had made the cowl for rear wheel:
My son was helping me in center of gravity alignment:)
The receiver is placed under wing:
And the battery (although initialy I was planning in visa versa):
Fuselage and wing edges are swifted by vellum paper on glue:
Stabilizer is reinforced by bamboo struts (they are fixed to wooden ruler in fuselage and to 1 mm balsa disks on stabilizer):
Everything is ready for first flight:
First "flight" had detected bad contacts in connectors between motor and ESD (in the best case engine was providing only half of thrust, in the worst motor was jerking in convulsions), also angle of engine slope was not properly enough:
This is first jump to fly with typical mistake of inexperienced pilots:
Shrub was an critical obstacle in second attempt but it was clear that heavy propeller derives the model to left:
I had good luck with crashes, only one chassis bar was broken (unglued).
Next day both rain and bad weather were came and I hadn'l luck for flying. Then the contest died soon:(
Of course I was having mood lover than plinth and aircraft was sent to upper shelf. But this winter I met a wonderful man, he is
chief of aeromodelling club "Colibri" in Lobnya. His name is Vyacheslav Retunskiy.
We had decided to resurrect the project. Angles of engine slope were fixed and the aircraft was painted by acrillic paints:
And finally the first true flight had taken place at May 22, 2016:
The final conclusions:
1) The aircraft is stable on flying. The behavior to climb was detected but it was cured by trimming of elevator
2) Newertheless roots of wing consoles should be reinforced somehow, the behavior to tear root ribs out were noticed in on-wing landing cases (watch the video with shrub)
It seems to be all, thanks a lot for your kind attention! :)