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Alternative materials for building structural components


karoliina
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Hi all,

 

There have been a lots of talk against deviations from the materials

described in plans. However, the plain fact is that

there are dozen canard projects in Finland and only one of them

is flying and have proven to be successful. Not because of the

material, but because of other things. However, the interesting thing is that the only Cozy which is flying, is not made of Ez-Poxy or other approved

materials but from vinylester resin which was not purchased from

the US stores like Aircraft Spruce. I have talked with the guy and he have

said that the hardest part was that there was no exact data available

about the Ez-Poxy and he had to prove the stiffness by other means.

If someone has exact specs of Ez-Poxy (including all strength

etc. parameters), I would be grateful to see them. Ez-Poxy is not

necessarily the world's best aircraft material and there might be some

european alternatives which would rival it or be even better than the

original Ez-poxy. To be able to do the research, specs are needed.

 

Also about the glass used in the Cozy project, which are its parameters

including weight per square meter?

 

Best Regards,

Karoliina

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MGS is approved epoxy (and preferred by some) and it is a German based company. MGS 285 and 335 can be used.

 

Kevin

They have English, German and French versions of their website at this URL:

 

http://www.mgs-online.com/

 

I have read only positive comments about MGS resins. People are reporting reduced odour problems, very high strength, especially if post-cured, low viscosity even at room temperatures, etc.

Kumaros

It's all Greek to me

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  • 2 weeks later...

Hi,

 

I noticed that the MGS epoxies are approved by German aviation

authorities. They appear to be suitable for aircraft use indeed.

Good to know.

 

How about the glass material then:

What type of glass cloth is being used in Cozy?

Specs (strength), weight per square meter, apparently it is E-Glass rather

than S-glass etc.? There are plenty of options available already here

in Finland ranging from 48 g per square meter up to heavy stuff.

 

Really interesting thing what I just heard by the way is that

Cora (microlight) was done from polyester resin instead of epoxy some

years ago (I have been participating a service and maintenance

course where I heard that).

When the Finnish guy did some repairs with epoxy, they

said that it is unapproved material and don't meet their quality requirements.

Instead of believing that, the Finnish guy had said that they should

consider switching to epoxy. After all, they did... Another thing

that I also noticed, Woodcomp fiberclass Kremen propeller was

made of Norpol 440 boat polyester resin. That is cheap yes, I have

20 kg of that and it costed about as much as 2 kg epoxy, but the strength

is not very nice especially considering that it loses strength after +30C

temperature.

 

Best Wishes,

Karoliina

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Karollina,

 

The main problem in building an aircraft like the Cozy, EZ or dragonfly using vinyl ester resin is that that material dissolves styrofoam. This is the material that is used for the cores of the wings, canard and winglets. This is not a great thing to happen. I believe that the Glassair uses either epoxy or vinyl ester resin and Lancair uses the other, however neither of these aircraft utilize styrofoam (polystyrene) in their wings.

 

Dissolve to black.

 

Rich

I Canardly contain myself!

Rich :D

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Hi,

 

snipped...

 

How about the glass material then:

What type of glass cloth is being used in Cozy?

Specs (strength), weight per square meter, apparently it is E-Glass rather

than S-glass etc.? There are plenty of options available already here

in Finland ranging from 48 g per square meter up to heavy stuff.

 

Hi Karoliina,

regarding your questions about materials for the Cozy, you can download the complete building instructions manual (minus full scale templates) for the AeroCanard, which is 99.99% Cozy, from the Aerocad site at:

http://www.aerocad2.com/

That's what I did when Jeff Russell put it online a couple of months ago, and that's what gave me the final push to order plans and hopefully start building soon.

With friendly regards

Kumaros

P.S. I'll use MGS epoxy, picking it up myself at the factory in Germany, in order to get fresh material and avoid hazmat shipping charges, and foam and glass material sourced locally; so we are in the same boat ;-) so to speak.

It's all Greek to me

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Yes, indeed, same boat and stuff and I think I will propably do the same if/when

I proceed with the actual building...

 

I have actually downloaded the Aerocanard plans.

 

First, prior doing a canard aircraft of some sort, I will do a new

engine cowling for my current plane (TL-96 Star) which

I purchased a short time ago. The current shape is not aerodynamically

ideal and I am investigating if I could replicate the shape of TL-2000

Sting's cowling and do my own similar one therefore to the Star

(I would use that for training of the epoxy etc. use). The engine

cowling happens to be one of the places which can be (heavily)

modified by the owner despite the plane is a factory built one (not a kit,

but still it is an experimental anyway).

 

I noticed that there is no importer as far as I know for MGS epoxies

in Finland. Hmm. Maybe, should I become one? The customer base would not

be great, but...

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Has anyone used carbon fiber instead of fiberglass, and is the weight savings worth the price? :)

 

Mixture of materials (glass /carbon/kevlar) is possible and used many times, but it must be done with knowledge of the materials. The dragonfly spar uses carbon caps. HOWEVER, when mixing materials, the stronger (for want of a better word)material will bear most of the load until it snaps and then transfer the load in a rather abrupt manner to the other material possibly causing a failure mode less able to bear the stresses than either one of them separately. It is unwise to haphazzardly mix matials without the proper engeneering backround. Pure carbon can easily be used for cowlings, etc where it doesn't share load with other non-carbon structures, and a great weight saving can be realized (It even lightens your wallet at the same time)

 

Total carbon planes are somewhat common. The Lancair IV is all carbon as, I think was Spaceship I as well as the Starship.

 

Carbon is not a pantacia, however. Look in Spruce's catalog for a rating of the physical properties of the various materials readily available. (first page of Composite material section)

 

The best carbon is on a perfectly cooked steak

 

Rich

I Canardly contain myself!

Rich :D

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Hi,

 

Yes, Starship is made of quite 100% carbon with Nomex honeycomb core. Not the cheapest materials around, but has good weight/strength ratio.

 

My current plane, TL-96 Star (is called as StarSport in USA), is made of mainly fiberglass and the wing spars are made of 100% carbon. It seems

to work that way.

 

The teacher at aircraft service and maintenance course that I am attending

told that it is common to put one layer of glass on top of a carbon part.

The carbon can not be sanded or it will lose its strength, so he said it is

good to put one layer of ligthweight glass on top of carbon to avoid

damage to the carbon when finishing the outerior of the part and also in use the glass on top of the carbon protects the carbon below from impact

damage that the carbon is not good to withstand. He had an example of

carbon structure there for demonstration,

it was a such Nomex honeycomb sheet which had

carbon on top of it (it was from MD-11's floor if I remember it right).

Little hit and there was an ugly hole in it.

 

I had a chance to sit in the cockpit of a very nice Airbus

yesterday by the way at Finnair's maintenance.

The flight simulators tend to give that kind of impression that

the visibility from the cockpit of such passanger aircraft would be

quite limited, but it could not be more

wrong. The visibility out is excellent (allthough not as good as in my plane

which has a full transparent canopy of course)

when the seat is adjusted right and

the ergonomy to the side stick and other controls is very nice. The side

stick looked very much like the Infinity Aerospace's stick. The aircraft

is 100% fly by wire. V-nice...

Pity that I am not allowed to fly a such thing...

 

Best Wishes,

Karoliina

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  • 3 weeks later...

Mixture of materials (glass /carbon/kevlar) is possible and used many times, but it must be done with knowledge of the materials. The dragonfly spar uses carbon caps. HOWEVER, when mixing materials, the stronger (for want of a better word)material will bear most of the load until it snaps and then transfer the load in a rather abrupt manner to the other material possibly causing a failure mode less able to bear the stresses than either one of them separately. It is unwise to haphazzardly mix matials without the proper engeneering backround. Pure carbon can easily be used for cowlings, etc where it doesn't share load with other non-carbon structures, and a great weight saving can be realized (It even lightens your wallet at the same time)

 

Total carbon planes are somewhat common. The Lancair IV is all carbon as, I think was Spaceship I as well as the Starship.

 

Carbon is not a pantacia, however. Look in Spruce's catalog for a rating of the physical properties of the various materials readily available. (first page of Composite material section)

 

The best carbon is on a perfectly cooked steak

 

Rich

 

quite correct carbon unfortunately comes in different grades similar to e and s glass some of the carbon (pan fibres) have lower structural properties than glass this leads some to believe carbon is stronger than fibreglass

in many cases it doesnt quite ring true

 

higher strength fibres are also misunderstood despite having higher physical performance properties used alone they can still fail

layering or layup is what makes a composite part perform correctly or have its required properties making a component purely from a high grade fibre can be as detrimental

 

in simple terms carbon is great for stiffness ie highly loaded components which rely on strain to failure ie wing spars or components using these fibres in conjunction with others means that an optimized strength to weight can be acheived iusing combinations of materials to arrive at a desired result

 

i dont also believe that most builders have the equipment to process carbon the majority use wet layup which is fine however this yeilds the laminates which tend to be heavier and more void prone than other higher end processing methods im not expecting the pre preg and autoclave method to be high on most peoples skill list but believe me if its high performance carbon you wont see many reaching for the vacuum bagging film

 

composites are usually validated by their void content or most will use fibre to resin ratio if the part is resin rich it may be weak but if it is resin dry then it is far more dangerous carbon is harder to wet out than glass using wet layup methods

 

in terms of weight you will find that a badly processed carbon part can be heavier and weaker than an correctly processed glass component so if you did use a carbon cowling then it could still be heavier and more expensive than a glass version

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  • 2 weeks later...

hi canardian .,

im matteo zangi frome rome italy ..

i have the same problem about the cozy item to buy .

i found in italy Angeloni and is the italian dealer of mgs .. i phone today and he say ok for the epoxy (mgs 285).

but for the foam he say to reserch a sweden company called DIAB .

for the rutan fiberglass nil ... i haveto found out the spec ..

help !

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hi canardian .,

im matteo zangi frome rome italy ..

i have the same problem about the cozy item to buy .

i found in italy Angeloni and is the italian dealer of mgs .. i phone today and he say ok for the epoxy (mgs 285).

but for the foam he say to reserch a sweden company called DIAB .

for the rutan fiberglass nil ... i haveto found out the spec ..

help !

Greetings Matteo,

 

I remember that about 18 years ago there was a battle between our fearless leader Burt Rutan and a small supplier of fiberglass (Ira Hale ) located in the town of West Texas who was selling an equivalent material to Burt's (uni and bi) except that it came in 60"wide rolls. Burt tried his best to get it taken off of the market, including I believe threats to Spruce and wicks to withdraw support for their companies should they carry the material. Of ourse, it seems that the whole thing was about $$$$. Under pressure the company reformulated their bonding cemical and the material turned out to be stronger than burts. but was still discredited by burt. Many Dragonfly aircraft were built from that material (including my own) I believe Burts material was manufactured by Hexel and the rogue company was Burlington Mills.

 

If you have a source for burlington fabric, find out what the equivalent materia is in their inventory.

 

This is all from memory of over 18 years ago. The company that originally sold the material was Alpha plastics which was then bought by another company and I believe that company was purchased by Aircraft spruce and exists as aircraft spruce west, in georga.

 

Good luck with your fiberglass hunt.

 

If all else fails, can't you import the fabric from the USA??

 

By the way compositepro, carbon tows, I believe 6"wide were very successfully used with room temp cure composites in the spar caps of all dragonfly aircraft. these caps were combined with a bidirectional shear web to form the spars of the wings, canard and rudder.

I Canardly contain myself!

Rich :D

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Greetings again Matteo,

 

I just looked up the numbers of the glass that we used in the dragonfly that I mentioned before.

 

The Bidirectional cloth was 7500 it is a 10 oz cloth 60" wide

The uni was 7715 no strength given provided in 30" widths

 

The invoice was from 1983. The bi was $3.40 per yard and the uni was $2.80

I Canardly contain myself!

Rich :D

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the big deal is to find out in europe the same foam .

for the rutan fabbric i will buy from ac spruce , is not so heavy , and may be teansport with a small sum (and i dont want to build an aircraft with the wrong but so similar fabbric ! at 10k feet i dont want surprise !

the foam you know is a pallet !

ac spruce ask for ship a fortune !

bolt , nut , other small i canbuyfrom ac spruce !

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