NASA demonstrates shape-memory alloy actuator to fold F-18 wing

NASA tested a new actuator made from shape-memory alloy to replace the regular actuators to fold an F/A-18 wing. The intent is to produce new alternatives for actuators and whatnot as part of the Adaptive Wing project. As they note, adaptive wings have been done before, but apparently not with this newer tech. They have demo'ed it on the ground (see the mildly annoying video) and plan to get it to be flight worthy. Whether it makes it onto the flight line is another story.

While I am thrilled because it seems pretty darned cool, I am a at a bit of a loss as to what the advantage is over the old actuators. I am not trying to be a curmudgeon here, but rather would like a real explanation of the potential benefits. Perhaps someone here could explain?

a reply to: anzha

Think of a bird's wing. How it can change shape; camber, twist, and aspect ratio. It means one ship can operate in a very wide envelope.

That's hard to do. That's what they are working on.

I think.

a reply to: anzha

So they are making something more complicated and doesnt work as well as a normal actuators yet. And its more expensive not sure the point of doing this other than to say hey look its cool.

originally posted by: dragonridr
a reply to: anzha

So they are making something more complicated and doesnt work as well as a normal actuators yet. And its more expensive not sure the point of doing this other than to say hey look its cool.

It's called research and continuous improvement. You keep running iterations of design, test, analysis and modification until you get the outcome you want.

a reply to: anzha


It reminds me of the material that the story says the man found in Roswell. If I remember correctly, when he folded it up it would straighten itself back out. Hmmmm. Good OP.

a reply to: highvein

No. Mylar is different.


But there is this:
jmmedical.com...

originally posted by: Phage
a reply to: highvein

No. Mylar is different.


But there is this:
jmmedical.com...

That was interesting. Thx. Using heat to activate the molecules. Through temperature manipulation shaping metal. I wonder how many practical applications there are?

At least you can see first how how an X-Wing fighter will transition its x foils into attack position.

a reply to: anzha

Reminds me of inconel or how ever spell it

originally posted by: penroc3
a reply to: anzha

Reminds me of inconel or how ever spell it

Nitinol.

a reply to: chr0naut

Yep
www.abovetopsecret.com...

a reply to: chr0naut

ohh so close, thats what i get for posting from the watering hole.

originally posted by: penroc3
a reply to: chr0naut

ohh so close, thats what i get for posting from the watering hole.

Yeah, I have a coffee spoon with a handle made out of a bit of Nitinol wire.

Twist it all up, dip it in warm beverage and 'sproing', straight as a die.

I feel like we did a lot of SME-related work with both SMA's and SMP's in the 90's and the cost/risk/fatigue factors really came nowhere close to being worth it. I don't have a citation handy, but mechanical actuators had a much better shelf-life, worked faster, and generally had fewer manufacturing challenges. Weight was a toss up depending on the forces involved. I don't think the physics have changed much, whatever the material science advances.


Variable span adaption is still a worthwhile area of pursuit, imo. But I wouldn't spend my own money chasing SMA's instead of actuators unless someone has come up with something radically different than what's been around.

a reply to: anzha

I am a at a bit of a loss as to what the advantage is over the old actuators

Weight and size.

With SMA actuators you can get 5-10 times higher power/weight ratio compared to geared dc motors (which are the next best thing).

originally posted by: highvein

originally posted by: Phage
a reply to: highvein

No. Mylar is different.


But there is this:
jmmedical.com...

That was interesting. Thx. Using heat to activate the molecules. Through temperature manipulation shaping metal. I wonder how many practical applications there are?

Aircraft wings that change shape according to temperature and air velocity?

a reply to: stormcell

I just sort of skimmed the video, so maybe he answered, but shielded FMSA would be the way to go over temperature-affected material. Stronger, faster, easier to give exact inputs, don't have to worry about aerodynamic heating, etc.

There were some polymers available, too, that had three-states through thermal manipulation that people got excited about, but I'm not sure they'd get enough umph to overcome aerolastic forces and the weight of the wingtip in this application and the temperature differences necessary would be extremely difficult to manage. Or atleast not the polyurethane materials I ran across.

Getting all the closer to full active actuated skin that replace control surfaces thus allowing for slicker low RCS craft think of being able to have a B2 type platform with none of the the clamshell drag spoilers for flight control. The applications are crazy to think about it super F14 anyone? Variable sweep using these? Seems like it would be stronger and more efficient. Also think about the clever beam steering you could could do for laser beams with this tech? This is Betty cool stuffs!

originally posted by: penroc3
a reply to: anzha

Reminds me of inconel or how ever spell it

Lol I was about to say super high heat stainless?!?!

originally posted by: Phage
a reply to: anzha

Think of a bird's wing. How it can change shape; camber, twist, and aspect ratio. It means one ship can operate in a very wide envelope.

That's hard to do. That's what they are working on.

I think.

I'm leaning more towards they want to put these in the foldable wings for when they go on a carrier. It'd make sense- less hydraulic pumps, lines, and whatnot- the plane will be lighter. It'll also be easier to maintain (HOPEFULLY).