radjet

Introduction:

The nano drak didn't cut it for me. It handles well, but is a tad heavy for my tastes. I wanted something lighter and faster.

Components:

  • Radjet clone

  • T-motor Velox 2208 2450kv motor

  • Amax 60A 6s ESC

  • TBS crossfire nano rx

  • Noxe F4 flight controller with Barometer (flywoo version)

  • Beitian 220 GPS

  • Foxeer Falkor micro camera Caddx micro cam

  • Emax ES08MA II Analog Metal Gear Micro Servo x2

  • Tramp HV vtx with foxeer antenna FX799T 200mw vtx

  • Buzzer

Conclusion:

491g dry.

Update 11/2/21: Maiden went ok. I was only able to put in one flight because the control linkage broke while I tried to adjust it after the first flight. I also lost control while tuning it as it spun wildly out of control. Fortunately, I was at a high enough altitude and was able to gain control back in manual mode. It was very roll sensitive though, so I need to go less aggressive on the linkages.

Update 11/4/21: Flew a couple more flights before stripping one of the control horns on a gentle landing. Decided to move the linkages to the top of the wing instead. Other than that, it requires quite a bit of left trim to get it to fly level. Still lots of tuning on this one and will need to try many different props.

Update 11/16/21: Rebuilt this completely after a fatal crash into the river. The only things which survived were the servos and the crossfire nano rx. This plane suffers from a death spiral in which recovery is pretty much left to chance. I've encountered this quite a number of times and have successfully recovered about half the time when I have enough altitude. Top speed I've been able to achieve so far on 4s is about 174km/hr which I think was with the 5.5x4.5 prop. I haven't pushed it much with the 6" prop. I think the 6" prop is great for general flying whereas the 5.5 is good for speed. With the 5" prop, launch throttle is 80% whereas it is only 70% with the 6". My general feeling so far is that this is a good fast cruiser, but not the plane I've been looking for since it has unrecoverable stalls, which makes it too unreliable. Whenever it encounters the stall, applying throttle seems to make it worse and the only hope is to move around the elevons in hopes of regaining control. I also feel that regaining control would be made easier if the control surfaces were larger. I did not position my servos with the maximum throw since I prefer more precise control, which could also contribute to the lack of recoverability.

Update 12/4/21: I got it flying pretty efficiently with the F80 motor. It cruises pretty fast and I like it quite a bit aside from the death spirals. If I can get rid of that by swapping out to longer vertical stabilizers, I may get more of these kits.

Update 12/6/21: I extended the vertical stabilizers rearward and that pretty much allowed the death spirals to be recoverable again. Ultimately, this means that this is inherently a design flaw in the airframe itself because modifying the CG had no affect. With the extended stabilizers, the spirals are now turn into more of a spinning dart towards the ground which is recoverable by just turning the elevons in either direction and then pulling up to regain control. However, this platform still lacks space for more/larger batteries and it doesn't seem as efficient as the dolphin.

Update 4/3/21: With the 2216 2600kv motor on 4s 6x4props, the top speed is in excess of 165kph. It is still not as efficient as the dolphin nor does it fly as well.

Efficiency Logs:

  • 13.3km (1301mah used) | 4s lion | 97.8mah/km