Composite panel 'flat-pack' construction

[ColinC]

Hi,

I have been thinking about how you might find novel methodologies for a fast-build aircraft and how back in the 70's and 80's when I was building model aircraft things changed almost overnight with the advent of CNC cutting. My first 'Pilot' brand model of a generic Cessna with its CNC cut lite-ply (poplar ply) fuselage was a revelation as it was accurate, self jigging and quick to put together.

Now it seems unlikely that the lite-ply construction could scale up, but the tab and slot construction could be applied to a suitable material. I originally came across Fibrelam many years ago and I think that something similar was used in the CFM Shadow fuselage structure. There are many companies producing similar products. It looks like the sort of material that could very quickly be cut on a CNC router (or manually with a router and template) and then bonded together with epoxy and tape to make a composite structure of very predictable weight, strength and accuracy if a little boxy.

Here is a link to an article outlining fabrication processes and it helps illustrate its potential: http://www.hexcel.com/Resources/DataShe ... nology.pdf

regards,

Colin

[ColinC]

I also spotted that I wasn't the only one to spot the potential:

http://www.retroplane.net/forum/files/optimist_195.pdf

And, I like the idea of spending government money on our own project:

http://www.flightglobal.com/news/articl ... ype-24019/

regards,

Colin

[Ian Melville]

I too keep looking at the CFM Shadow frame that has been at the Flying Show for many years, and wondering if there was technology that I could use there.

Wonder what happened to the EA9?

[neilld]

This is exactly the kind of thinking required for the "Carling/Carlsberg" idea. Can we get John Edgley involved - he appears to be a master at attracting funding for new projects? Is he a member?

DFN

[Ian Melville]

Expanding on my post this morning. I like the idea of self jigging parts CNC cut. Though we may have to change the title to 'if IKEA designed aircraft...'

We could even build out own router as was done by one CX4 builder.

[peejack]

John Edgley has already designed and built a fibrelam aircraft which was at a Cranfield rally in the late 80s early 90s. Sorry cant remember the name, Regards Peejack

[neilld]

Suspect you're thinking of the EA9 referred to above.

[Andy Kennedy]

Isn't the AMF Chevvron motorglider built from flat panels of some type.

I've always liked its rather odd looks.

Would love to have a short wing, 'aeroplane' version, but suspect it might need a bit more poke...

Why was its construction method discontinued? Cost? IP retention?

Andy

[Brian Hope]

Hi Andy, I don't think the construction techniques was so much abandoned as the design ran its course. I believe he chap involved with the Chevron did have a new design two seat motorglider which he showed at an Expo when it was still held at Booker. Not the prettiest aeroplane to some eyes but it promised pretty good performance. I think he was looking for funding, it seems to have disappeared from the scene though. Not sure if it used the same sort of construction as the Chevron.
The 'flat pack' composite has also been used in a US kit aircraft. A guy named Steve Rahm developed what he calls the Fold-a-Plane scene and it is used in a single place Corvair powered aircraft called the Cruiser. see: http://www.youtube.com/watch?v=Sw7xafhj9ZI .
The infamous Jim Bede also used a similar idea for another single place design, the BD17 Nugget. Like many Bede designs, the promised kits never went into production and I think it died a death, sad because it looked to have promise and was worthy for its interesting and potentially affordable and simple construction method.

[Ian Melville]

Brian has just reminded me that I was going to ask for a supplier of Fibrelam that is a realistic price. It seems to be very expensive stuff.

[Bill McCarthy]

"Klegecell" is another core material - used, I think, in the wing construction of the "Cri-Cri" and the "Luciole". I received a few samples of the stuff years ago and it's as tough as nails and very light.

[Ian Melville]

Thanks Bill, I will look that one up.

[neilld]

Hi Andy, I don't think the construction techniques was so much abandoned as the design ran its course. I believe he chap involved with the Chevron did have a new design two seat motorglider which he showed at an Expo when it was still held at Booker. Not the prettiest aeroplane to some eyes but it promised pretty good performance. I think he was looking for funding, it seems to have disappeared from the scene though. Not sure if it used the same sort of construction as the Chevron.
.

Suspect you're thinking of the Magnum http://www.aviationenterprises.co.uk/P5%20Projects.html
It wasn't a motorglider, more a VLA type. I think Angus Fleming did a presentation on it at one of the rallies some years ago.
DFN

[Andy Kennedy]

The 'flat pack' composite has also been used in a US kit aircraft. A guy named Steve Rahm developed what he calls the Fold-a-Plane scene and it is used in a single place Corvair powered aircraft called the Cruiser. see: http://www.youtube.com/watch?v=Sw7xafhj9ZI .

I'm aware of the fold-a-plane, something with a flat 6 corvair engine should have really been a two seater...
Neat idea though, you'll still require a masters degree in sanding to get a nice finish though....

Anyway beware not all foams are equal, see this interesting discussion about Fold-a-planes and Glasairs....

http://www.homebuiltairplanes.com/forum ... usion.html

Andy