Contact US

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!

*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

Aircraft Control Surfaces to Fixed Surface Gap Question

Aircraft Control Surfaces to Fixed Surface Gap Question

Aircraft Control Surfaces to Fixed Surface Gap Question


We want to minimize the gap between the control surface & fixed surface of the wing. Currently, our Control surface leading edge has round shape as shown above and the wing shroud (or closeout shroud connecting the top & bottom skins) is also similarly shaped. Our control surface acts as an elevator and hence deflects both upward and downward. We have noticed that in downward deflection, the gap between the wing and control surface grows large enough to affect performance. This issue is further exacerbated by large twists that exists towards the tip of the wing.

Since it is a conceptual study, I am free to modify the shape of control surface LE and also corresponding shroud. Just looking for some ideas on the same. Would appreciate any pointers folks.

RE: Aircraft Control Surfaces to Fixed Surface Gap Question

Moveable surface gaps can be sealed in various ways depending on aircraft size. At the smallest simplest end, elastomeric seals or even fabrics, at the larger end of the scale, flexible or hinged panels.
However it sounds like you are able to change the leading edge profile, I'd start by looking at that, provided it does not affect performance.

RE: Aircraft Control Surfaces to Fixed Surface Gap Question

Thanks Ng2020...sealing is an option which we have not considered so far...but something to consider. Yeah, the intent of the study is to determine if LE shape affects performance...I'd start by reducing the LE round shape to a much smaller curvature...

Anyways, thanks for your replies. So far, I was not able to find out alternate shapes for control surfaces LE profile...sounds like circular one is a winner :)

RE: Aircraft Control Surfaces to Fixed Surface Gap Question

The latest development work is on morphing wing shapes that have continuous outer skins that are flexed into different shapes, so that there are no gaps in any position.

RE: Aircraft Control Surfaces to Fixed Surface Gap Question

Morphing wing tech might be out of my/our ability...BTW, are there any practical examples of morphing wing being used? Definitely something to consider

RE: Aircraft Control Surfaces to Fixed Surface Gap Question

The Wright Flyer :)

RE: Aircraft Control Surfaces to Fixed Surface Gap Question

NOTE. I believe Your use of terms in the problem definition is non-standard... and I'm confused by Your problem elements.

As I 'hear Your issue'... this sounds really like 2-major/spearate problems…

Torsional/bending wing-stiffness [or lack-of-stiffness] for control-forces reactions and...

Control-surface-to-wing/stabilizer structure... 'gap', 'fair' and 'seal' for consistent control surface power/moment/min-drag.

Also, in the 'real-world' you may need to be wary-of [concerned-about], the effects of weather [IE: moisture/rain/snow/ice/abrasion-erosion, etc] and maintainability [IE: degree of difficulty access/alignment/fastening, etc] and flutter or random/tramp-vibrations and internal-structure load reactions due to control actuation and feed-back.

NOTE. The design of control surfaces interfacing to wing/stabilizer structure has been addressed in various NACA or NASA reports... lots of ways to accomplish what You are asking about... but, I'm drawing blanks about which-ones... and no-time to search for You.

Just random thoughts...

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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