Servers by jDrones

Conventional takeoff for VTOL Tilt Rotor?

(Alb Cem) #1

Hello all,

Is there a way to configure the appropriate firmware for VTOL tilt-rotor to accept conventional take-off (roll forward on runway with 0 deg tilt on the rotors)?

Best regards

Cem

(James Stewart) #2

One of the Q_Options bits allows for this. The one you’re looking for is “Allow FW takeoff”.

(Alb Cem) #3

Thank you James for the quick response, it is helpful.

As follow up,

can the firmware can be made to accept a hybrid attitude for the tilt-rotors during “conventional” takeoff?

The idea is to use partially tilted rotors to assist with the lift generation and shorten the take-off distance in cases where the total weight with the payload is beyond the full VTOL capacity and runway length is limited.

Any insights about the practicality and implementation of this?

Thanks

Cem

(Peter Hall) #4

this is not posible in the current code, not in a nice way in anycase. You could maybe enable qassist, and try it. But then you have a plane that thinks it is a can hover but dosent have the power, would need some added mini-airspeeds, or just locking out of all Q-modes.

I’m not really sure this would give a shorter take off in any case. Would it not be better to commit to gaining airspeed a quickly as possible? A steep climb also uses the rotors to assist lift generation. I guess you could use the vectoring to rotate sooner in the takeoff run…

(Mark Whitehorn) #5

You could experiment with this PR: https://github.com/ArduPilot/ardupilot/pull/11763
Manually apply some forward tilt in QSTABILIZE then throttle up and see what happens…

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(Vitali) #6

Hi, could you check next link, I think it is the same idea with your: https://www.youtube.com/watch?v=GCajkPvCayg&list=PLX6uatB_XGjU_hFuRsUYsAn1Sgbz2JIqd&index=88&t=0s

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(Alb Cem) #7

Good catch Vitali - this is exactly the idea! Thanks.

In response to iampete´s valid pushback on whether it is better to take off conventionally rather than with partially tilted rotors, I ran some back of the envelope calculations to minimize the take-off run and depending on the thrust to weight ratio, there is an optimal tilt angle for the take-off. In some instances, it is better to use conventional takeoff as iampete suggests, in others it is better to go for a “hybrid” (partially tilted rotor) approach. Clearly if the thrust to weight ratio is above 1, Vertical Takeoff (90 deg tilt angle) is automatically the optimal.

In the video, the take-off run appears extremely short in ahybrid approach. I think the thrust-to-weight ratio is close to or above 1, which means the vehicle could have as well taken-off vertically.

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(Mark Whitehorn) #8

Yes, I think you could do that with my PR. None of my VTOLs have landing gear though.