Servers by jDrones

Dual-motor tailsitters

( research air) #422

no problem, weather going bad for the weekend, noreaster

(lorbass) #423

Solved the issue with shaking elevons by reducing the radial distance at the servo lever.
Now, the angle of the elevons is +/- 25 degrees.
This angle was not enoughe to hold the position and the Wing drifted with full up elevon backwards.
I tried to yaw the Tailsitter by 180 degrees in order to get it back. To hold this critical pitch and to get it down
was to much for the instable System. And it made a flip and crashed.
Heavy destroyed, also my motivation.

( research air) #424

this is what Dave’s been up to… very jmpressive

(kd0aij) #425

@tilt Great video; I wonder what trades are involved with placing the rotors at the wingtips vs inboard.

@lorbass Sorry to hear about the crash. I’m having better luck with my Stryker than I ever did with the Caipiroshka configuration:

It’s much less susceptible to crash damage since the props are protected by the wings and fins.

(tridge) #426

very nice! Great to see thrust vectored tail sitters being used by NASA

( research air) #427

wing tip vortice control, more efficiency I hear 10% more efficiency of the wing in ff

( research air) #428

Hi, Tridge
thinking of putting my board in gray to test if it’s a hardware issue, also have a avau x2 which software
flavor would I use?

( research air) #429
Tridge, check this out, might be perfect for OBC

(kd0aij) #430

@tilt I have an AUAV-X2 in my Stryker; build for px4-v2

(kd0aij) #431

@lorbass Were you using Leonard’s attitude compensation patch when you had problems with the elevons oscillating? My testing indicates that the net effect of that patch is to significantly increase PID gains at low throttle, which would probably be the cause of the problem. See my comment here

and my flight log here:

(lorbass) #432

No idea, I just flashed latest master.
But the shaking elevons where already without running motors.
And they shaked also with PID reduced fro o.35 to 0.1.
I think tailsitter with elevons only is a compromise between shaking elevons and good steering effect.
At least with small, ligth wings.

As a first reaction, I wanted to stop the chalenge but after sleeping some nights
I recovered the motivation and decided now to continue with the vectored tailsitter.

(kd0aij) #433

Glad to hear you’re going to keep at it. I think the vectored approach has great potential.
Leonard’s patch is not in master, so that wasn’t the cause of the shaking. Must have been due to excessive PID gains, as you say. Did you try moving your CG back to allow using lower gains in Q modes?

(lorbass) #434

The CG was at that point as discribed in the manual of the Caipirinha. (Plane mode)
But may be, to high on the wing considered in plane mode. So the balance was difficult in hover.
The battery, the power modul, the Telemetrie TX and the BEC where sunk in the wing, the rest (RX, FC, GPS) on top.
Another fault was perhaps the usage of analog Servos. Yesterday Rolf told me thats not correct.
I will change it and see if the shaking is gone. If not, go back to the original elevons which are smaller.
I think with vectored they don’t need so wide. This helps compensate the weigth of the additional Servos for Tilt.
You see, hope dies last.

(Ian Conway Lamb) #436

Shoot me an email through the contact form if you want any more details on the aircraft :slight_smile: Looking to do transition tests in the next month or two.

( research air) #437

Hey, started work on a TVBS stryker ,what’s the c/g range, just have the $ 20. wing no info[quote=“kd0aij, post:425, topic:15302”]
I’m having better luck with my Stryker

(kd0aij) #438

I have the F27C and the CG is about 15mm behind the recommended location:

(step 5)

I’d expect you can use standard size elevons and the recommended CG with a vectored thrust arrangement though. My flying weight is 870g with a 3S/2200 LiPo

( research air) #439

very helpful, thanks… I will post results soon

(lorbass) #440

Hi all,
You remember my issues with shaking elevons?

Just tu help other greenhorns like me (6 years copter experience only) this information.

You need digital Servos for APM Plane (at least master) else it ends with shaking elevons.
Thank you Rolf !

No idea if this is everybody clear, I never read this somewhere.

Now, no shaking elevons anymore.

( research air) #441

it kinda flies, sometimes

(lorbass) #442

Sometimes it dances.
Your simple wing was really stable for takeoff.
May be to light, the same for my planned Caipirinha?
Which FC are you using?