Rahul's RC Aircraft and other designs

EXPERIMENTAL HYBRID MULTI-ROTOR Experimental Quad, to test the concept of having major part of the lift,  being provided by a different setup than the standard lift cum control motors of a multi-rotor . We know that 1.Larger props are generally more efficient in generating lift 2.Currently, IC engines setups  have better endurance than pure electric setups The experiment was to test such a setup where the major proportion of the lift is provided by efficient large diameter, low rpm props. In the initial setup,  this lift generation would be driven by low consumption, low KV electric setup.. . In the next stage, the lift generating setup electric setup would be replaced with IC engine setup, for substantial increase in in range/duration and lifting capacity Concentric contra-rotating props would have been ideal.. however, in the absence of a ready concentric contra-rotating gearbox, the option was to have two contra-rotating props suitability placed in a symme...

This is a 1000 mm span aerobatic aircraft, in the lines of a pattern ship built during covid lockdown The wing is symmetrical , constant cord Span : 1000 mm Cord : 200 mm + 40mm aileron Airfoil :FX 77080 and 15% thickness The wing is hotwired, and the leading edge is fiberglassed with 100 gsm FG, upto 25%. This itself acts as a spar. Something like a D box.  The full length ailerons are 5mm depron covered with paper for stiffness The tail assembly, horizontal and vertical stabilizer, are constructed our of 5mm depron , with the leading edge (upto 25%) covered with paper Fuselage is box construction out of 5mm depron. The underside is fiber glassed  with 100 gsm FG The cowl was modified and the ailerons were trimmed to align with the wing tips She is beautiful .. both in looks as well as in flight characteristics.. hammerheads are perfect, rolls are controlled , it flies as if on rails..  

A pivoting wing design in the lines of Mignet's Flying Flea Front wing : Span : 755 mm Cord : 155 mm Airfoil : NACA 23112 Dihedral Rear wing Span : 510 Cord : 155 mm Airfoil : NACA 23112 No Dihedral Motor : 2204, 1400kv, 3s 1500 bty, 30A ESC, 7x4.8 prop, 2x 9gm servos. All these are reused components , and specially the motor/bty/esc combination could have been much smaller and lighter Horizontal separation of wings 15 mm, Vertical Separation of wings 85 mm Wanted to keep the construction  simple Both the wings have the same cord and airfoil. This makes construction easy in terms of hotwire airfoil template / ribs> The wings are hotwired out of EPS, and the leading and training edge have been laminated. There is a 3/4 span 3 mm CF road in the front wing.  Two thin Aluminium "L" section have been epoxied at 20% of the cord, on the bottom surface of the front wing. The lower prong of the "L" have holes through which a bolt attaches it to ...

A fast rc aircraft for flying for windy days (not a floater). Main design aspects, around 36" span, Plank Flying Wing, like funjet (not swept back and hence no twist), low drag, higher wing loading,  high power /wt, symmetrical airfoil. Material blue foam / insulation board / XPS..  Airfoil NACA0009, thickness 9%. , hotwired the final dimensions are 1. Span =  880mm / 34.6" 2. Root cord = 250mm / 9.8" 3. Tip Cord = 150mm / 5.9" 4. Sweep = 30mm / 1.2" CG @ 15% = 44.5mm / 1.75" Wing area = 17.52 sqdm / 271.6 sqinch / 1.88 sqft The wing was hotwired out of blue xps. The fuse is also blue xps, hollowed at some places , with some strengthening Initially I was planning to have a CF sparred wing covered with monokote ..  hence, according to the earlier plan , the wing  has CF spars  and a CF tow, while the fuse has balsa and an aluminium channel embedded for strength. Latter on, in midst of the construction, decided to cover the whole aircraft w...

This is the build of a large coro delta It is made out of 3mm and 2mm coro..  Wing Span - 1200mm Root Cord- 765mm Tip Cord-250mm Sweep -485mm Dry weight - 1020gms Motor ;3630 1100kv, 40 amps, 3S 2200mah, 2 x 12gms servos CG -280mm from nose tip (at 15%) With a total wing area of 609000 sq mm and a AUW of 1200 gms the wing loading is at 6.4 oz/sqfeet, which is in the region of slowflyers.. this combined with a not too small Reynolds number for the avg cord, translates to  good stall characteristics. It is quite a big aircraft. The underside is 3mm coro and the topside is 2mm coro..  The spar is a  tapering XPS foam wrapped in fiberglass. This makes the spar very strong.. in fact this spar is the only load bearing structure in the whole aircraft. For gluing coro to coro, fevicol SR (a rubber based solution) was used and epoxy was used for foam to foam or foam to coro or wood.  The TE was also taped up after gluing. The controls are through full l...

One of the exposed part of the antenna in one of my V8FR II FrSky receiver had broken To repair it, I just stripped off the outer shielding for 31.5mm, in the damaged antenna... have a look at the pics below. The difference in total length is apparent and does not matter much so long as the exposed/unshielded length is correct.

This is a 40 inch SR71 built of 5mm depron/biofoam It has two tractor motors, one each in the LE of the nacelles.. The plan has some modifications in the aspect ratio and other dimensions, and the details are as below Controls are just elevons on the outer wings (outside of the nacelle)  with 1 X 9gm servo each.. there is no moving control surfaces on the central portion of the wing or on the vertical tails.. btw the vertical tail surface are straight and not canted inwards. Note , the LE droop on the other wing panels. The landing gear is  tricycle wire skids.. to protect the prop and underside of the aircraft.. have a look at the photographs below The finished aircraft , just before the 1st flight. Notice the bty compartment... because of the low roll/ lateral stability the bty had to be in the center, hence the fuse had to modified.. and before that the CG had to be right.. First flight was done with the CG at 30.5" from the tip of the nose.. ...