Rahul's RC Aircraft and other designs

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.. ...

A small aircraft based on the swift bird, saw a similar one in RCGroups and liked it, and decided to make one.. 24 inch wing span, KF2 wing,  AUW 86g, including a 1811, 2600KV motor, turning a chopped 4.5X3 prop and a 2S 300mah bty.. no spar on wing .... it is a light and small bird The pictures explain the build better It flies amazingly (bio mimicry is real).. stable and has flown hands off. here is a video https://www.youtube.com/watch?v=sDYZjwUOt4E Also another video of the aircraft in a dogfight with a kite(bird) https://www.youtube.com/watch?v=h4ubSP_iVe4&feature=youtu.be

This is delta with a canard. Overall it looks a cross between a Eurofighter and a Viggen ..  High alpha flight was desired, hence the canard has a fixed front plate set at 0% and a moving rear plate.. more like a tail plane with a elevator.. (pics speak better than words).. For pitch-up, the canard rear plate moves down and the elevons move up.. The canard is controlled by a separate servo (5 gms) The wing platform is a delta with a KF2 profile. The leading edge of the wing is covered with newspaper which has been applied with diluted PVC glue . After shrinking it forms a nice , smooth and taunt surface , and also adds to the torsional rigidity. The wing has two 1mmX3mm CF strips glued to the top and bottom to acts as a spar (with the 6mm foam in between them) The test flight showed tendency of sudden onset of tip stalls and dropping of a wing.. To delay this two wing fences were added to each wing ... also it had landed badly and damaged the motor mount (tail-...

I use single component polyurethane for majority of my foam projects.. it bonds strongly with expanded and extruded polystyrene (thermocole/ depron),  does not eat/corrode foam, it is light, allows time to  align parts, and cures to a hard finish. Used many brands, .. but the BEST is what I was able to source  as a sample from Mumbai based Krishna Antioxidants Pvt, Ltd, CRISTOFIX PU 9. .. Thanks to Mr. Adarsh  from Krishna Antioxidants for taking the pain to understand the requirement and helping me with a sample. This product has a long shelf life allowing for better storage and prolonged use, and low viscosity  compared to big brands like Fevicol, Araldite The way I use it it to decant a portion of it into a large disposable syringe.. use the plunder to ease out the air bubbles, and then cap the nozzle. And to use it, just unplug the nozzle and squeeze  the plunger.. it keeps the air out of the syringe and enhances shelf life by by months.... i wish ...

This is a F-18 with 30" span and with a 2826 2000Kv motor It is based on a scale F18 Growler with some changes in the dimensions.. refer to the picture below for the dimensions It has ailerons, elevator and rudder as controls and one CF spar in the wing Has a wire skid fixed undercarriage, and can do a rolling takeoff from a decently flat surface.. A good  flyer, and with the heavier parts (motor, bty) close to the CG was quite maneuverable  .. The finished but unpainted version.. the picture gives a feel of the size The canopy can be removed to access the battery compartment It has flown many sorties.. and has been retired and parts recycles (like many of my planes.. storage is a challenge) Here is a flight video  https://www.youtube.com/watch?v=YPAsXsSOFqg&t=8s

This is a build log for a 54" flying wing with a blended fuselage  Made out of Styrofoam and hotwired Wing Span -  54" Airfoil - MH 64 Root chord - 14" Tip chord - 7" The wings were hotwired out of styrofoam based on a MH 64 airfoil. The spar was a strip of 1X3 carbon fiber glued in a shallow groove on the top and bottom surface of the wing. The two strips of CF act like a I beam with the foam in between, and being very strong in tension, makes a very rigid wing. There was a central section 6.5" wide fuselage, which was blended with the wings. This would help by having more space for power train & electronics  The CFs extended into the central section , which gave more rigidity and strength and intregrated the wings and fuselage better The LE was covered with very thin fiber glass to reinforce it against dents A view of the wings and fuselage joined together.. note the space being cut for electronics and battery.. . this would lat...

Building a high flight time RC aircraft, which is easy to carry and fly, made out of easily available materials (foam), and reusing my existing electronics After deliberations, decided on a  simple dihedral (rudder and elevator) tractor of 40" span..  Wing chord was kept at 7" (below that airflow disruption due to low Re number)  It would be flying at low Reynolds numbers (around 80000),accordingly a thin and slightly  under-cambered (4 degree) plate airfoil section was chosen. The dimensions / parameters were calculated based on the design requirements and based on RC aircraft parameters. This aircraft regularly flies + 45 minutes flights on a 1000 mah bty..and is super easy to fly . Many a times after reaching a good altitude & trimming the aircraft I have taken a short break. She can hold bearing even in windy conditions. Just by pointing her into a decent wind and with very minimal ground speed (zero or sometimes negative)she can gain altitude. DIMEN...

This is a 40" span KF flying wing Airfoil is KF2, 50% top and 7.5% Root Cord - 25cm, Tip Cord - 25cm , sweep distance -25cm CG -17.5 cm from wing leading edge It has one CF spaning the whole wing.. Latter version had 2 X 3mm spars Bty- 1000mah 3S 2228, 1400kv 7X5 prop AUW with cam - 465gms I did not quite believe in the advantages of a KF airfoil .. but this aircraft flies (glide ratio, and sink rate)  much better than a flat plate wing... and the difference is quite noticeable .. She is a great flyer.. good climb, good glide.. very stable, once trimmed can fly in a thermal with  minimal inputs. Stalls are predictable A video from a on-board cam https://www.youtube.com/watch?v=3VPjojkbF04 The first aircraft broke apart in mid flight when trying to pull up after a high speed pass..  as the design was very good was tempted , and built a second aircraft  on the same lines .. more strengthened (with 2 X 3mm CF  spars in the wing.. the e...