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-   -   Putting a design quest to you lot ! VTOL (http://www.Wattflyer.com/forums/showthread.php?t=72862)

solentlife 12-26-2013 10:27 PM

Putting a design quest to you lot ! VTOL
 
OK ... I have some ideas ... but interested how you lot would attack this from a scratchbuild point.

My vision is a standard light trainer with 3 small props in short shrouds. One out in extremity of each wings span giving lateral and main weight lift, third further back to balance the model.

The two wing units could rotate 90 degrees to give full back thrust and proportional thrust through 90 degrees to vertically down. The rear unit being throttled to balance the two forward ... once full forward flight - the rear unit stops.

Or a forward standard prop with the 3 vertical units, both systems throttled to perform their functions.

OK - over to you lot ... any ideas ?

Remember this is a scratchbuild not a "buy it" solution thread.

Nigel
(Yes I'm bored !)

CHELLIE 12-26-2013 11:11 PM

Here you go Nigel :D Click on the Video in the Link.

http://www.yellow-bl.de/flightsystems.html

http://www.yellow-bl.de/fs/tilt607.JPG

CHELLIE 12-26-2013 11:27 PM

No Need to Tilt the wing, thats just more of a Hassle, just tilt the motors.

dgjessing 12-26-2013 11:55 PM

Quote:

Originally Posted by CHELLIE (Post 935290)
Here you go Nigel :D Click on the Video in the Link.

Cool!

JetPlaneFlyer 12-27-2013 12:12 AM

The 'VTOL' part would be very easy to do using a tricopter set up (fixed lifting rotors on wings and pivoting tail rotor for yaw control). Pitch and roll would be accomplished in the normal multi rotor fashion by varying power to each motor and 'tilting' the entire plane rather than pivoting the motors. This could be done with a cheap KK2 controller and off the shelf multi rotor parts.

The problem there would be that the rotors would be fixed in the lifting position so could not be used for forward propulsion, which is a big problem.

The challenge with the tilting rotor idea is stabilisation, I think that it would be just about un-flyable without some form of artificial stability and I don't know of any off the shelf controller that would do tilt rotor. It would be interesting to find out how it was done in the video, that looked very stable, they only mention one gyro.

hayofstacks 12-27-2013 01:00 AM

take a high lift and slow flying model like a slow stick. mount two counter rotating motors on the tail, then two large motors on the wing. run the standard motor. this way you could fly it like a regular plane, but take off and hover vertically. it would also greatly lessen the load during forwards travel and using the stock front motor for forwards thrust will take some complications out of the equation.

id also counter rotate the four motors to help with stability. and if the model ends up a bit heavy, you could add thrust to help maintain altitude.

DHC Beaver 12-27-2013 03:28 AM

Interesting idea,but I think it's all been done before.I remember an english fellow building a Harrier using 4 directional fans donkeys years ago,and believe he did fly it in conventional flight.The vto apparently required a huge amount of extra power to transition from hover to forward flight.I would imagine you would also need some gyros to aid stability.
The model shown by Chellie has some similarities to the Osprey,but that had huge props,and no tail power unit.
I have an interest in oddball aircraft,so I'll be watching with interest.

hayofstacks 12-27-2013 04:00 AM

id use a slow stick. I really think its the way to go.

throw two 480 sized motors on each wing with 55oz of thrust each with an 11" prop should easily lift it. tail motors add stability for the tail only. if you added the motors at cg and ran a large battery upfront it would be really simple.

solentlife 12-27-2013 06:33 AM

Quote:

Originally Posted by CHELLIE (Post 935298)
No Need to Tilt the wing, thats just more of a Hassle, just tilt the motors.

No the wing is fixed ... it's the thrust units that tilt.

I would be wary of just 2 motor units as then you have no control over pitch in any air movement.

I'm leaning towards 3 small units, 1 at each wing outer section and 3rd at tail ... fixed and a tractor prop up front.

Lift .. then throttle in the tractor prop ... as she gains flight speed slow to stop the lift system. Simple and without need to rotate or hinge anything.

Nigel

JetPlaneFlyer 12-27-2013 10:22 AM

Quote:

Originally Posted by solentlife (Post 935339)
I'm leaning towards 3 small units, 1 at each wing outer section and 3rd at tail ... fixed and a tractor prop up front.

Lift .. then throttle in the tractor prop ... as she gains flight speed slow to stop the lift system. Simple and without need to rotate or hinge anything.

Nigel

Nigel, in that case a tricopter set up is the way to go. The two wing tip motors would be fixed, they could be put in shrouds set into the wing to minimise drag in forward flight. The tail rotor pivots to provide yaw control.

This is standard tricopter arrangement, tried and tested, and flight controllers are readily available and cheap (Hobbyking KK2 for instance) with pre-configured settings for tricopter.

This is my tricopter flying in 15-20mph winds:
YouTube Video
ERROR: If you can see this, then YouTube is down or you don't have Flash installed.

solentlife 12-27-2013 12:31 PM

Hi JPF ... yep that's the idea ... but it contravenes the Scratchbuild intention as put in OP ... not out of box solution.

But definitely on the right track.

OK ... so shall we agree some 'ground rules' ? To try and keep in the scratchbuild arena ..

No formal out of box model. This includes a frame / motor / controller set-up termed BnF .. PnF.
Separate parts to combine into an own designed VTOL / flight system is encouraged.
Final model is a scratchbuild from plans or own design, designed or modified to have VTOL built in and incorporated into structure.

Nigel

JetPlaneFlyer 12-27-2013 01:04 PM

Nigel,

I wasn't advocating any sort of 'out of the box' solution. My suggestion was purely to use proven multi-rotor principals and electronic flight controller, and maybe a tri-rotor pivoting tail rotor mechanism. Obviously the actual airframe would be scratch build and ESCs motors etc selected to suit.

If you aren't up for using off the shelf electronics then this project is going to be a big challenge when it comes to motor, ESC, receiver and servos, let alone flight stability controllers;)

Steve

PS and FWIW the tri-copter in the video was built from separate 'loose' components, and is not a RTF / PNP / BNF or anything of the sort. It did use a proprietary tri-rotor frame but some do build their own frames.

solentlife 12-27-2013 05:13 PM

OK .. sorry JPF ...

Bit of a misunderstanding there. I agree that full own scratchbuild is going to be difficult, but I was trying to avoid a out of box frame and then a sort of plane config bolted on ! I think you saw that in my meaning.

I agree that control and set-up is going to lean very heavily on such as the tri-copter means to 'get of the ground' ( :rolleyes: ) ...

One factor that is going to affect how it's done is the weight lifting capability of the lift rotors. A standard tri-copter is unlikely to be able to lift a 600 - 800gr addition to it. So the idea will need to be refined and upgraded to allow decent power levels to achieve the lift.

Nigel

solentlife 12-27-2013 05:15 PM

Can you imagine the possibilities though ?

Instead of pure multi-rotor or pure fixed wing .. a combo of the two and flyable in a small back garden.

Nigel


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