×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Perching Glider

Perching Glider

Perching Glider

(OP)
Hey guys,

I am currently constructing a manoeuvrable glider capable of a fast pitch up (similar to how birds perch). For the design of my wings I was thinking just to use thin balsa wood sheets with an elliptical planform. I am aware that conventional aerofoils are designed to operate efficiently for AOAs below 15 degrees but I am interested in the manoeuvre, which will be at very high AOA (up to 90 degrees). My question is that will the aerofoil shape be really important for this case?

Thank you :D

RE: Perching Glider

When I hear "elliptical planform", I think "Spitfire".

When I hear "high AOA", I think "Helio Courier".

You might want to read up on both, and think about how they apply to your problem.

Mike Halloran
Pembroke Pines, FL, USA

RE: Perching Glider

No, the shape of the airfoil will not matter much at very high AoA, basically the low pressure side will be completely stalled. This does not mean your idea won't work, since quite obviously even a flat plate can produce lift in those conditions.

You may want explore multi element cascades of flaps, these can handle very high aoA without stalling.

I wouldn't get too excited about planform.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Perching Glider

(OP)
Thank you Greg, that's what I wanted to know.

RE: Perching Glider

do you want the wing to generate lift at high AoA ?
I'd look at the pitch up as turning the wings into a big brake, killing forward motion.
I somehow don't see the "perching" manoeuvre as being that simple ... are thinking of pitching the wing (only) or the whole glider ?

another day in paradise, or is paradise one day closer ?

RE: Perching Glider

Hi rds1g13 :
Entering recently this forum (long time absent) I found your question.
Read about airfoil POST STALL phenomenon...this occurs more frequently on HAWT (Horizontal Axis Wind Turbines).
But you will pay a price of a tremendous rises in airfoil CD beyond "normal" AoA...
Try with "Aerodynamics Coefficients at large angle of attack" by C.Lindemburg, December 4-5, 2000 NREL,IAE symposium, CO.
Cheers.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close