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All Forums >> Radios, Batteries, Clubhouse and more >> Unusual R/C >> RE: Osprey
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RE: Osprey - 2/23/2004 1:20:21 AM   
tiggerinmk



Posts: 1527
Joined: 12/30/2002
From: Milton Keynes, UNITED KINGDOM
Status: offline 		I'd hinge the wing from the main spar. This gives a suitable anchor point to attach whatever mechinism you'd use in place of the wing brace.

If you could find a high wing design that uses an aluminium tube as a wing joiner this would be ideal. You'd need a very powerful servo though to turn a complete pair of wings.

With the wing tilted vertical the ailerons would be acting as large rudders affecting yaw. Maybe a heading lock gyro would keep the plane pointed the right way? but I doubt if a gyro would really be necessary for that.
The main problem is controlling roll. The engine throttle would not really be quick enough in this application to counter a sudden crosswind gust for example, so putting gyros on the throttles I don't think would help. This is why people getting into this use cyclic controls and rotor heads instead of airplane props.

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       Post #: 26

RE: <span class= - 2/23/2004 2:46:06 AM   
angelrcdesign



Posts: 484
Joined: 2/8/2004
From: Weehawken, NJ, USA
Status: offline 		Hi my name is angel . You can find the 3D view on this page. ( http://www.fas.org/man/dad/sys/ac/v-22.htm ) it took me one weeeeek to fine a good view. for my plans

(in reply to runover1)
       Post #: 27

RE: Osprey - 2/23/2004 3:11:58 AM   
Ram-bro


 

Posts: 2003
Joined: 1/22/2002
From: Bennington, NE, USA
Status: offline 		Angel, it seems I cant see what you want us to see. Is this the right address?

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       Post #: 28

RE: Osprey - 2/23/2004 4:21:04 AM   
tiggerinmk



Posts: 1527
Joined: 12/30/2002
From: Milton Keynes, UNITED KINGDOM
Status: offline 		Maybe this is it?
http://www.fas.org/man/dod-101/sys/ac/v-22.htm

_____________________________

If you can remain calm, while all around you is chaos...
then you probably haven't completely understood the seriousnes

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       Post #: 29

RE: Osprey - 2/23/2004 4:25:32 AM   
runover1



Posts: 663
Joined: 4/27/2003
From: Lancaster, PA, USA
Status: offline 		Thanks for the site guys.

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RE: Osprey - 2/27/2004 8:58:24 PM   
angelrcdesign



Posts: 484
Joined: 2/8/2004
From: Weehawken, NJ, USA
Status: offline 		I think this is a good page. It help me out, and plus it has more links to help you even more.

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       Post #: 31

RE: Osprey - 3/26/2004 6:26:47 AM   
secretspy


 

Posts: 34
Joined: 9/29/2003
From: West Lafayette, IN,
Status: offline 		try this on for size:
http://www.gressaero.com
http://www.gressaero.com/papers.html

look at the proof-of-concept model

< Message edited by secretspy -- 3/26/2004 6:27:48 AM >

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       Post #: 32

RE: Osprey - 4/26/2004 2:59:47 AM   
kitsune4px


 

Posts: 3
Joined: 4/3/2004
From: Mountain View, CA,
Status: offline
A group in Germany has been working on a scale V-22 for a number of years now:
http://www.tiltrotor.de, unfortunatley the site is in German, but Babelfish does an okay job of translating it.

They make periodic updates to their website and the most recent one showed a hovering test rig in flight.

A couple of things to consider:

1) If you are going to build a scale V-22 then you should use cyclic and collective control of the prop rotor since this is how it's done on the real item. But I doubt if standard RC helicopter blades will work well since they have very little twist. If you look carefully at a tilt rotor the twist on the blade is -30~40 degrees from root to tip. That probably means making some sort of custom prop rotor blade.

2) The transition from hover to forward flight is non-trival. It will probably require some sort of gyro based automatic stabilization system.

3) You could build an aircraft using props, and use assymetric thrust and mast tilt for roll and yaw control, with a third aux thruster at the tail for pitch control in hover. But then you wouldn't have a V-22. For a good example of a tilt wing concept which used props look search the web for the XC-142 or CL-84. But be aware that the prop will have a smaller diameter and a higher disk loading, which means more power to hover at a given weight. Also I'm not sure what type of time delay constants are associated with throttling the engines that have been mentioned, but that could also cause problems with control. I think for a hover stability point of view, I'd go with the tilt rotor concept.

There are other issues to be thought about, such as whirl flutter. But it's best not to get overwhelmed by all the complications at once. Designing a scale tilt-rotor has been an idea I've had for a while now, but will probably have to wait for a future date.

Best of Luck

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       Post #: 33

RE: Osprey - 4/26/2004 12:24:29 PM   
runover1



Posts: 663
Joined: 4/27/2003
From: Lancaster, PA, USA
Status: offline
quote:

ORIGINAL: kitsune4px



There are other issues to be thought about, such as whirl flutter. But it's best not to get overwhelmed by all the complications at once. Designing a scale tilt-rotor has been an idea I've had for a while now, but will probably have to wait for a future date.

Best of Luck

A lot of good info that I appreciate. I tried to go to that site and it did not work, is it the correct address? Thank you and have a great day.

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       Post #: 34

RE: Osprey - 4/26/2004 7:51:46 PM   
kitsune4px


 

Posts: 3
Joined: 4/3/2004
From: Mountain View, CA,
Status: offline 		Sorry a mis-placed comma got in the URL:

http://www.tiltrotor.de

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       Post #: 35

RE: Osprey - 5/2/2004 11:17:29 AM   
couldbemage


 

Posts: 332
Joined: 4/13/2004
From: , CA, USA
Status: offline 		The problem with the osprey is also call "power settling" and affects all helicopters. This is when an increase in collective pitch during a rapid descent with little or no forward speed cause the rotor to stall due to a ridiculously high angle of attack. On a single rotor heli, this means you pull up on the collective and you drop faster, but if that happens it is really pretty obvious what is going on. With the osprey this condition is so very deadly because of its side-by side rotor configuration, and being a tilt rotor isn't even part of the problem(all side-by-side helis have this problem, maybe that is why there aren't any.)
When this sort of heli turns, it does so by in creasing pitch on one side, decreasing it on the other. This means that when the pilot pushes the stick to the right during a rapid descent, the osprey starts to roll left. Pilot then naturally cranks the stick farther to the right; left rotor loses all lift; osprey rolls violently to the left. Now it's upside down a few hundred feet off the ground.

Of course, the manual clearly says not to descend that rapidly. Most other aircraft exibit clear warnings before they fall out of the sky, but they did issue a warning.

ps. Pilot error is what happens when all liable parties that are still alive get together and lay blame.

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       Post #: 36

RE: Osprey - 5/4/2004 2:13:56 AM   
tartago



Posts: 126
Joined: 9/4/2003
From: Kuala Lumpur, MALAYSIA
Status: offline 		I saw Bob Kress from Kress jets deveoping a Vtol plane Osprey type.
I cannot remember where.

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       Post #: 37

RE: Osprey - 5/4/2004 2:25:21 AM   
tartago



Posts: 126
Joined: 9/4/2003
From: Kuala Lumpur, MALAYSIA
Status: offline 		It was an electric one.

try on kress-jetes.com

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       Post #: 38

RE: Osprey - 5/8/2004 2:48:23 AM   
Mitek



Posts: 183
Joined: 7/13/2003
From: Sacramento, CA, USA
Status: offline 		isn't it kress-jets.com?

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RE: Osprey - 5/23/2004 8:44:37 AM   
CaptainMidnight


 

Posts: 3
Joined: 5/20/2003
From: BrisbaneQueensland, AUSTRALIA
Status: offline
quote:

ORIGINAL: couldbemage

The problem with the osprey is also call "power settling" and affects all helicopters. This is when an increase in collective pitch during a rapid descent with little or no forward speed cause the rotor to stall due to a ridiculously high angle of attack. On a single rotor heli, this means you pull up on the collective and you drop faster, but if that happens it is really pretty obvious what is going on. With the osprey this condition is so very deadly because of its side-by side rotor configuration, and being a tilt rotor isn't even part of the problem(all side-by-side helis have this problem, maybe that is why there aren't any.)


I fail to see why the "side-by-side" rotor configuration as you put it is so deadly. A Chinook is a "side-by-side" helicopter turned 90 degrees, has been flying for years and has had relatively few problems. Perhaps the Allison T406 turbines are underpowered in this application, but I doubt it - they're pushing out more than 6,000 shaft horsepower, after all.

quote:

ORIGINAL: couldbemage

When this sort of