Tail_BoomStrike
Veteran
Location: Virginia Beach
| I mentioned earlier in this thread that I'm experimenting with another AXi motor using 400mm MAH blades. I was able to do test flights yesterday snd today.
I din't have much luck with the 3S set up. HS speed could only go as high as 2650rpm plus the head was bogging too quick and can't even do tic toc. The tail was holding very well though with the help of HDX 13T pulley that I modified to fit the Lepton. That pulley alone could load the motor pretty hard that on the bench without the main blades there is noticeably great amount of rpm lost when giving rudder input. So, I gave up the idea of "3S 3d Lepton".
4S I said to myself was next to be tried. I made the calculations some time ago. And I even ordered 4 different T500 pinions, hoping one of those pinions would put the HS on my target 2700-3000rpm. But thsoe pinions won't even reach the main gear I found out, unless I modified the motor mount. Too much work I said to myself Maybe some other time. But for now, I said, I'll just use the 2826/8. But then, just for the heck of it I said why don't I try 4S with this pinion (when I was testing 3S, I started from 20T down to 18T. Since 18T was already on there, might as well try it before I remove that motor, just to see what's gonna what's gonna happen).
I crank the throtle curve down to 75% straight across. ESC's set for governor mode. Spooled up, and when the rpm was not increasing anymore, I tached it. I was amazed at what I've seen..... 3250rpm.... I hovered it and the rpm seems not changing...... The tail become too sensitive.... It was wagging on piruete stops..... Remember the 13T pulley was still on....... I set it down, I want to do a different test..... I gave it 1/4 stick position.... That position have set up to have -6* collective...... I tached it.... And the rpm still reads 3200rpm...... I stood back and gave it full low stick...... RPM drop some then stabilized, yet still there's power... Back to midstick, then full negative again several times..... The HS recovery was very quick, no hesitaion..... I put it to hover again and started pitch pumping...... This thing could jump from 1ft hover to 15ft high at a blink of an eye...... 4min 30sec alarm on the timer went off, so I landed...... Time to jot down final readings on the watt meter.....
Motor: AXi 2820/8, 1500kv, 3S-4S on Heli
Battery: FP Evo20 4S 3700mah
Main blades: MAH 400mm
Flying weight: 1580grams
Watt Meter Readings:
825.3W peak
2.2Ah used
62.15A peak
13.26V lowest voltage drop
15.01V battery pack static voltage after 4min 30sec (that translate to 3.75V per cell)
3700mah, 80% of which is 2960mah. This particular test consumed 2.2Ah within 4 1/2min.... If the heli was to be flown in full 3D flight, this setup is good for 4min.
There were some readings I made during the test..... At idle 0* collective while sitting on the ground, amp draw was 18A.... When I hovered it then set it on the ground, watt meter recorded 26A.... 1/4 stick -6*, while siting on the ground, amp draw was 34A.... And, of course that 62.15A reading above was from full collective (collective pitch set at +-10*).....
I made another test this time lowering the throtle to 70%....... HS flatten to 3000rpm. Amp draw in every aspect except for the peak, went higher..... So that, I guess, means, for this set up, 3200rpm is the most efficient rpm...... This test lasted 2min only..... Little did I know the main gear got stripped...... So it'll be a few days when I recieved the gear I ordered before I could see how it would be like in 3D flight..... By that time it will be tested without the HDX 13T pulley....... And that should lower the amp draw a bit, tame the tail, and maybe lessen the chance the main gear getting stripped again....... |
HS i about 3000rpm not to mention the sound motor generates alone, scarrry
It does tic tocs in a blink of my eye and the cyclic is extremely fast too with carbon paddles form sjm500pro. The only drawback is that it gets hot really fast but that can be solved with additional fan You can get from Model Motors(made mine out of fiberglass).
