Hi all,
I have build a FT BRONCO thrust vectored belly sitter that’s good fun to fly if not super practical at this stage. It more or less a standard A tail bronco with custom motor mounts and a reduced center fuselage. Flying weight is abit less than 1kg.
Power:
4S 1400 to 1800, needs 4S to take off, the 1800mah is more or less the biggest battery you can get away with, get about 3 or 4mins or hover or much more forward flight
2x 40a escs, I used multistar brand
2x emax RS2205 2600kv motors with 5045 3 blade props, on CW and one CCW
Controller:
banggood pixhawk lite, cheap but connectors are none standard, defiantly buy some as well and a replacement SD card, the one that was provided only lasted a few flights.
banggood wifi telemetry module, these work well, poor range but ideal for changing parameters between flights straight from your phone
banggood mini GPS, nothing special but works ok
Servos:
4x cheap hobbyking servos for the control serfaces i used HK15178B
2x Power HD 1810MG for the vectoring, these are quite expensive, I have gone through them fairly fast, striped the metal gears on 3 and burned out the driver one one. You can open them up and turn the output gear round 180 deg if you have striped them but this is not ideal. Not really sure if its the large number of crashes I had while getting it set up or the quality of the servos. The vectoring mechanism does put a fair bit of load on them, possibly there would be a better way to do it or just move up to a larger servo. Also for the TVBS design abit larger range of movement would be nice.
Airframe:
just a standard FT bronco with A tail. No center fusalarge, I just cut a extra tail boom front section to hold the FC and battery. I have designed 3D printed vectoring mech that holds the servo and just hot glues in the front of the tail boom sections. The motor is then held on a 3d printed yoke. I have had no trouble with the 3D printed parts, they hold up well, possibly it would be better to have a weaker yoke to save on servos.
I cut the bronco from the foam board myself, this is OK but he waterproof kits from flight test are much nicer, I would recommend 3D printing a foam board bevel cutter, there are several on thingyverse, makes it much neater and quicker. A strip of strong packing tape along the leading edge before you fold over and glue the wing makes it much more robust. I also put standard clear tape on the hinge lines. I find strong double sided tape better and easier to apply than hot glue for gluing flat bits together, such as the wing spar to the wing. Then use the hot glue for end on to flat and right angle joints.
I will add the STL files for the 3D printed components and some close up pictures, I will also add my parameters, it flys ok in hover, it struggles with yaw abit in wind. There is a knack to getting nice transitions although it will do untidy ones fine. I have mostly flown in QStabalise and FBWA. Flys as you would expect a flight test aircraft to in forward flight, just make sure the cg is in the correct place. I haven’t done any stuff in auto modes although i see no reason why it wont work. I have been using it to get a understanding of the code and generally flying about like a idiot, so its rather batted now but it doesn’t seem to care. If it crashed I just add hot glue and tape and go again, so far i’m on airfraime no.2 and its nearly ready for no.2. Foam board is cheap.