Go Back  RCU Forums > RC Airplanes > Aerodynamics
Reload this Page >

NEED HELP!!! Scratch-building a V-22 Osprey

Notices
Aerodynamics Discuss the physics of flight revolving around the aerodynamics and design of aircraft.

NEED HELP!!! Scratch-building a V-22 Osprey

Old 06-17-2002, 04:08 AM
  #26  
Mike James
Senior Member
 
Mike James's Avatar
 
Join Date: Jan 2002
Location: Anchorage, AK
Posts: 2,565
Likes: 0
Received 0 Likes on 0 Posts
Default Remember Seth Cochran

I don't have technical commentary on this thread... I just wanted to say that you are a brave man for attempting this project. "Ambitious" might be understating it.

Hopefully you'll read and absorb all the information here and elsewhere, and keep trying. This is very cool, and as long as you can afford it, and you're safe, I say "Why not?".

Remember, if it wasn't for Seth Cochran, we wouldn't have warp drive!
Sincerely, good luck.
Old 06-17-2002, 08:19 AM
  #27  
Cactus.
Senior Member
My Feedback: (1)
 
Cactus.'s Avatar
 
Join Date: Dec 2001
Location: CamborneCornwall, UNITED KINGDOM
Posts: 6,136
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

V-22, i love that gimbeled little thing on your page. it gos to show my ideas are to simple for a propperly working final version, but i knew that anyway.
look at www.draganfly.com for a few ideas of how to use your rotors for yaw control and so forth
Old 06-17-2002, 09:43 AM
  #28  
v22
My Feedback: (8)
 
Join Date: Feb 2002
Location: Niles, Mi
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Phill
Yep ,I guess you can keep it simple ,but to do all the stuff the real one does you need all the heli stuff .I don't just want to jump into the air like a funfly hover plane and flop out of the sky into a controlled crash type of vtol landing.I guess I am just to picky

Yes I have a Roswell flyer which is the same as a dragofly and that would work if you were to build a quad rotor tilt rotor ,but bell don't have plans for that until this two rotor version takes off.P.S. I have tried to make the roswell into a quad rotor and it doesn't have enough lift to support any tilt system.

ttyl
Larry
Old 06-17-2002, 10:56 AM
  #29  
Cactus.
Senior Member
My Feedback: (1)
 
Cactus.'s Avatar
 
Join Date: Dec 2001
Location: CamborneCornwall, UNITED KINGDOM
Posts: 6,136
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

as far as i know, the Osprey has vairable pitch, not a heli blade set up. very low pitch for take off, and high for forwards flight.
its hard and heavy to do this, but you can use fun fly props and electric motors for very good control. the original indoor helis had fixed pitch.
i can hang my planes very controled, and electric motors have even more control and responce. a propperly balanced set up should gently hover into the air. pilot skill will say how smooth this is
i'd imagine the real one controls pitch with subtle auto movements of the nacells. after all, it carrys troups, they mess the CofG up real good.
am i also right in saying it dosnt truely hover? rather tilts the rotors forwards slightly and STOL
thats solves a whole heap of problems
Old 06-17-2002, 02:42 PM
  #30  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

phillybaby is right in that te real Osprey has variable pitch blades, NOT a heli setup. I've heard of variable pitch blades on models before, but those were on bombers and warbirds. Any use for a project like this?
Old 06-17-2002, 02:44 PM
  #31  
Johng
My Feedback: (4)
 
Join Date: Jan 2002
Location: Deland, FL
Posts: 1,927
Likes: 0
Received 0 Likes on 0 Posts
Default know more

Originally posted by phillybaby
as far as i know, the Osprey has vairable pitch, not a heli blade set up. very low pitch for take off, and high for forwards flight.
The Osprey does indeed have cyclic pitch control of each blade, just like a helicopter. I don't recall if it uses a swash plate or independent actuators for each blade - but the blades are controlled cyclicly - like a swashplate - when in hover.

its hard and heavy to do this, but you can use fun fly props and electric motors for very good control. the original indoor helis had fixed pitch.


But they had swash plates, didn't they!


i can hang my planes very controled, and electric motors have even more control and responce. a propperly balanced set up should gently hover into the air. pilot skill will say how smooth this is


Planes can hover because they have tailsurfaces to deflect the propwash. It's not just the motor. If you are trying to develop a scale V-22 - there are no control surfaces behind the prop. The above example isn't relevant.

i'd imagine the real one controls pitch with subtle auto movements of the nacells. after all, it carrys troups, they mess the CofG up real good.
am i also right in saying it dosnt truely hover? rather tilts the rotors forwards slightly and STOL
thats solves a whole heap of problems
No, none of the above is correct. It can do a rolling takeoff, but it is not a requirement of the aircraft . Hovering for TO and landing is normal. I've seen it myself, quite impressive, as is the transition to forward flight. Pitch is controlled with cyclic input to the blades - heli style. Why would you think it's easier to swivel a whole engine/nacelle/blade assembly than to just use cyclic?

Phily, you need to educate yourself before coming on here and telling someone (V-22) how to do it. He's obviously considered the issues at hand alot more than anyone else here. They S/N ratio of your posts is quite low.
Old 06-17-2002, 03:45 PM
  #32  
MinnFlyer
Senior Member
My Feedback: (4)
 
MinnFlyer's Avatar
 
Join Date: Apr 2002
Location: Willmar, MN
Posts: 28,519
Likes: 0
Received 7 Likes on 7 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

I think this will settle it:

http://www.boeing.com/rotorcraft/mil...2/1687-a3.html

It clearly shows that the V-22 Osprey has got helicopter-type roter heads
Old 06-17-2002, 04:36 PM
  #33  
Cactus.
Senior Member
My Feedback: (1)
 
Cactus.'s Avatar
 
Join Date: Dec 2001
Location: CamborneCornwall, UNITED KINGDOM
Posts: 6,136
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

whats S/N ratio ?
i didnt claim to know anything, i said ages ago if you want a million dumb ideas and maybe a good one ask me.
for me its Lazy options and cheats
( btw, that brushless motor is now for sale at WestonUK )

ok, blades, your saying that each blade turns as it gos round, so it acts like a heli set up, clever.... but impractial for models
reminds me of that snellflight heli that controls its tips motors in the same fashion.

Yes they had swashplates, i said fixed pitch because i was compairing heli blades to planes props for the purpose of hovering. you also dont have those high drag issues with the forwards flight if you use aircraft props. theres a turbine aerobatic model thread you should look at, hes overcomming all these drag problems

Hanging planes, yep, we have tail surfaces, but again, the refrence was to the amount of control you have over the thrust and there fore the ascent and descent rates. nothing to do with hovering a fun fly. my hangs are all over the place, but i can control height ok.

i said am i right? not i am right. its only a model, cheat if you have to, if you dont mind losing hover and all its problems go for a STOL
it's a start.

And maybe thats where my one good idea was in all this, build a simple test bed. so now i'll let you all get on with it
Toodle pip
Old 06-17-2002, 08:52 PM
  #34  
v22
My Feedback: (8)
 
Join Date: Feb 2002
Location: Niles, Mi
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

The real v-22 uses helicoter swash plate with cyclic controls to hover and then locks them out somewhere between heli and airplane mode.

It actually does use LARGE airplane props. They are as long and wide as a heli blade ,BUT are twisted (47 degs) and tappered just like an airplane blade so as to deal with the forward flight drag that philly mentioned .

I have tried twin vectored ( differential tilting ) engines on the wing of a light airplane and can tell any one that wants to try ,that it will not hover in ground effect good enough to take off and land like a true VTOL.Balance is a big problem on it between hover and forward flight .Now if you just want to jump into the air and thump back down into a landing then you have a cheap VTOL.

I don't consider it a vertical take off and landing aircraft unless it can hover in ground effect for several minutes with out touching the ground and then be able to convert to airplane flight and back to a serveral min. hover and then land gently.

I think that a true VTOl is what Noah is trying to build not just a funfly twin engine plane.
Old 06-24-2002, 05:22 PM
  #35  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default First Prop tests

Yesterday I recieved my 16X8 prop. I want to test a normal prop instead of a heli one first - i guess i'm just stuborn like that . I don't have any flight motors or batteries yet, so i just attached it to a Dumas 12volt boat motor with a 12V battery just to see what kind of thrust this huge prop could produce. While it wasn't enough to actually lift I can tell with a gearbox and a actual airplane motor this thing will make PLENTY of thrust. The dust was flying off my workbench! But the best part was the sound - man that's nice.


HOWEVER, MinnFlyer is correct, a prop this big does act like a gyro. Holding it in my hand, i could feel it constanly wanting to return to a "neutral" position. One thing I did notice though, was that the gyro effect only lasts till it get's to about 45 degrees. So, when i'm holding in in a hover postion and i start to move to airplane mode, it is difficult to move till you get to 45 degrees then after that it moves easily to the horizontal postion. But it didn't feel as though it would be strong enough to rotate an entire fuse. Maybe that's because it was spinning relitively slowly compared to what it would be doing in actual flight - i don't know. At current, i just dont see this being able to rotate a 5 pound fuse. We'll see.
Old 06-24-2002, 06:17 PM
  #36  
MinnFlyer
Senior Member
My Feedback: (4)
 
MinnFlyer's Avatar
 
Join Date: Apr 2002
Location: Willmar, MN
Posts: 28,519
Likes: 0
Received 7 Likes on 7 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Ahhh, now consider this...

Is it strong enough to rotate a Zero lb fuse? Because that is essentially what you are rotating... 2.5 lbs forward of the nacelles, and 2.5 lbs aft.

As long as you're doing tests, try this... Balance a fuselage on something like the back of a chair. Now see how much force it takes to push the nose or tail down.

Oh, and add one more thing to the equation...
A vertical lift aircraft, while in hover, generates a high-pressure "bubble" of air directly underneath itself. And until a sufficient altitude is reached, the craft wants to "fall off the bubble". Think of it as you, standing on a 5 foot diameter ball in a swimming pool. Just ask the Heli guys. They will tell you all about the bubble.
Old 06-24-2002, 07:37 PM
  #37  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Your right, i didn't remember that the fuse is essentially weightless in this type of aircraft.
Old 06-25-2002, 12:19 AM
  #38  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

I've been considering this for a while, but have just now decided to bring this up. I know it not really scale but couldn't i use a air-jet system to control the movement while in hover (just like a harrier does). The holes could be kept small and would not ruin the scale appearance. It just seems like this is really the only way to control a model like this feasibly. A plus is the control surface and the jet could work simultaneously, thus eliminating the need for different flight modes on the radio. While in hover, the control surface would move, but obviously, the jet would be doing all the work. Vice versa in forward flight.

P.S. this could also help fight the "gyro effect"
Old 06-25-2002, 01:16 AM
  #39  
v22
My Feedback: (8)
 
Join Date: Feb 2002
Location: Niles, Mi
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Noah
The harrier "puffer pipe" system would work but not real good.Take a look at Eric Dainty's Harrier link that is on my webpage and go towards the bottom of his page and you can see to avi's of his flying .He makes a wobbly leap into the air and then comes bouncing back to the ground for a landing.True it is a real feat that he has done ,but even he will tell you that it is not what he wants the bird to do.At any rate take a look at his system for the roll and yaw and pitch moments.They really are quite unique and might just work for what you want to do.
Good luck
Larry
Old 06-26-2002, 01:29 AM
  #40  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

His link doesn't seem to be working!?
Old 06-26-2002, 09:35 AM
  #41  
v22
My Feedback: (8)
 
Join Date: Feb 2002
Location: Niles, Mi
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Noah
Dang !! It does seem to be down.I will do some investigating tonight and if I find that he has moved it or closed it I will try to email you the information.
Larry
Old 06-26-2002, 07:43 PM
  #42  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

v22 (or anybody else that might know),

I've been looking around on the web for cross-sections and larger 3-line drawings of the aircraft. I can't seem to find any sources for these more detailed things, just general drawings. Are there any good sites out there with these things?

In case anybody is interested check out http://www.usni.org/freestuff/v22osprey_datafile.htm All you have to do is register (free) - just type in name and e-mail and you can download a FREE V-22 program. Is has some specs and a 3-D osprey, pictures, and some more info. Go to the bottom of the page and click "register now" or something like that.

Another thing that I am curious about is the airfoil. What airfoil does the real one use? I'm thinking that the model probably would have to have a high lift glider type airfoil because the wing is so small. I mean tiny! The fuse is longer than the wingspan. It must have a horrible wing loading. Would it be wise to use a scale wing size?
Old 06-26-2002, 10:04 PM
  #43  
v22
My Feedback: (8)
 
Join Date: Feb 2002
Location: Niles, Mi
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Noah
I too couldn't find any real good drawings.The 3 views that Boeing has are what I used.I imported the drawings into RcCad and strecthed the RcCad model to the v-22 drawings and then the program drew up the formers that I used to build mine.

The full scale use a NACA 64 A214 airfoil if I remember right and the engineer at the Brandy wine airport musuem told me that the wing loading was in the 100 LB/ sq/ft area.He also said that it doesn't make any difference as the real bad area for wingloading is takeoff and landing and since that is all done in helicopter mode you don't have to worry about wingloading much.Unless you plan on looping and rolling a v-22 which is the other area that wingloading affects.My last years bird was in the 79 /sq area and it would rotate from a 60 deg. forward nacelle rolling takeoff ,until I remade the gearboxes and run the wingloading up to 110 /sq area or so.My total weight at that time was 18 LBS. /out fuel.

I ran an airfoil program called Designfoil by John Dresse and found that a NACA 64 210==== different than the 64A airfoils=== seemed to have the best lift for what weight I had.Then I found a place that tells all the airplanes airfoils and it seems this is the airfoil that Bell used on the first tilt wing ,the XV-3.It was heavy underpowered , recipircal engine===just like ours.So that is what I have been using.

My wing is almost the same length as the fuse.( fuse 58 "/ wing 52") I figured a little more wing would maybe help and not show to much.I also have a wider chord than the real one.(10"==about 1 " more than would be scale).

Hope this helps some
Larry
Old 06-27-2002, 02:21 AM
  #44  
Keno-RCU
Junior Member
 
Join Date: Feb 2002
Location:
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Check out this site for a detailed 4-view of the Osprey with cross section of the fuselage and nacelle.

http://www.airwar.ru/other/drawe.html
Old 06-27-2002, 09:37 AM
  #45  
v22
My Feedback: (8)
 
Join Date: Feb 2002
Location: Niles, Mi
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Keno
Good find
Old 06-27-2002, 06:32 PM
  #46  
Noah-Moore
Senior Member
Thread Starter
 
Join Date: Apr 2002
Location: San Francisco, California
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

Keno,

Thank you Sir, your majesty, sire.

Great drawing - i'm having it blown up at kinkos as we speak!
Old 08-23-2002, 07:00 PM
  #47  
banktoturn
Senior Member
 
Join Date: Aug 2002
Location: Bloomington, MN,
Posts: 762
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

If you're not locked in on the idea of a V-22 scale model, there are some simpler approaches, along the lines of the last couple posts. Many years ago, an engineer friend of mine and I really got the bug to design and build a V-22 model, and after we talked it over, we ended up deciding we couldn't do a faithful V-22 with our resources. We did think we might have a chance of taking off and landing vertically, using control surfaces which are being blown by the prop. You need to be able to control the thing a little bit, but I don't think you need to be able to do everything a helicopter or V-22 can do. Taking off is fairly simple, if you over-power the thing and use a prop which favors static thrust. For landing, you can picture going into a stall that ends up being a hover. At this point, you need to have at least some ability to move the thing laterally. We thought you could have a special control surface, not unlike flaps, near the wing root, which gives some side thrust. To 'steer', you need to make sure that the ailerons have some authority, or else have some differential in your 'thrusterons'. Needless to say, we never built the thing, and it's a far cry from a cool, scale V-22, but it might be a simpler way to get VTOL.

Have fun.

banktoturn
Old 08-26-2002, 06:46 AM
  #48  
CrashMaster-RCU
Junior Member
 
Join Date: May 2002
Location: istanbul, TURKEY
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

If U use electric motors, for eleminating Gyro effect, move batteries tail to nose during transition. It's simplier than using rotorheads.
Old 10-27-2002, 11:54 PM
  #49  
IanMansfield
Junior Member
 
Join Date: Oct 2002
Location: Shropshire England
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default V22 Osprey

This is a subject that I have been trying to find more information. Sorry Guys but I have only just joined your heated debate.
I am looking to manufacture an osprey of approx 96" wingspan using two petrols converted from glow engines using an electornic syncrinisation between the 2 engines from roll control. My thought on the tilt mechanism would be a worm drive from electric motors controlled from servos.
If when landing and taking of the aircraft is operated with engines at 45' then take off and landing can be made relatively slowly in aircraft mode with normal aircraft controls.
If there is a stiff breeze then the rotors can be moved into a more vertical position using the breeze over the surfaces for control.
Am I missing somthing on this?
Old 11-01-2002, 10:14 PM
  #50  
Phil Cole
 
Join Date: Jan 2002
Location: Redwood City, CA
Posts: 763
Likes: 0
Received 0 Likes on 0 Posts
Default NEED HELP!!! Scratch-building a V-22 Osprey

I suspect the roll control will be a bit unwieldy. The response will be quite slow, based on the response of fixed-pitched helicopters with rotors of that size. A gyro might help.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.