Internal control of camber

[Sparky Paul]

Camber changing...
From a source in my reading room..
The internal rotating horn idea taken to a higher level..

[Al M]

I bet once you built one you would have wished you hadn't.

[Sparky Paul]

I've done a simpler version.. many people have, for controlling flaps, ailerons, rudders and elevators.
This one is more complex in that it maintains a good camber for multiple sections.
Unfortunately it was installed on a poor airframe, so nothing much ever came of it.

[Salto]

Interesting Sparky,
It looks like a multi stage RDS. I wonder how they skinned the wing?

Graham.

[Sparky Paul]

According to the article.. "The subspars were piano-hinged (presumably at the top) and the bottom skin near the trailing edge had a sliding overlap".
...
"..the static and dynamic frictions associated with the sliding overlap controls degraded the longitudinal flying qualities to an unacceptable level."
.
Getting all those rotating joints working at model sizes would be "interesting". :)

[Al M]

I bet.

Before I retired I had some involvement with a machine for testing a variable diameter rotor blade. The scary thing was that as testing progressed it became clear that it did work and with not too much more development could be flown. Funding stopped and the project died.

[Majortomski]

Sparky, didn't NASA fly something similar on an F-111?

[Sparky Paul]

Sparky, didn't NASA fly something similar on an
F-111?
Yes...
The "Mission Adaptive Wing"..
http://www.dfrc.nasa.gov/Gallery/Photo/F-111AFTI/HTML/

[Jeremy Sebens]

I've done a simpler version.. many people have, for controlling flaps, ailerons, rudders and elevators.
This one is more complex in that it maintains a good camber for multiple sections.
Unfortunately it was installed on a poor airframe, so nothing much ever came of it.

This project was undertaken at my alma mater, Mississippi State University, at the August Raspet Flight Research Lab (though it wasn't named that at the time). The airframe that was the final configuration wasn't such a poor one as all that...

The XAZ-1 was a proof of concept vehicle that led to the XV-11A "MARVEL" (Mississippi Air Research Vehicle, Extended Latitude). The MARVEL logged a successful light test program, but like so many projects, languished from lack of funding after completion. The continous camber mechnaism was combined with boundary layer suction to acheive extremely high lift coefficients (I don't recall exactly how high, but numbers greater than 4 come to mind).

The MARVEL was revived in 1982 for use as a desert aircraft with new wings, this time with fowler flaps, since the variable camber did not outperform fowler flaps without the boundary layer suction, and that was deemed too difficult to maintain in a sandy environment.

Here's a link to the project summary at RFRL: http://ae.msstate.edu/rfrl/pages/marvel.html

[Sparky Paul]

Thanks, Jeremy.. it's always interesting to see where these things lead to.
I noted in the report that stall speed was enhanced by adding wing area.
That always works! :)