Carbon Fibre Undercarriage

[Peter Miller]

I am told that there will be an article in another place on how to make your own fibreglass undercarriages. Not sure how long it will be.

[Mastercrashman]

I've received the new carbon fibre U/C but have not, as yet, fitted it to the Acrowot. I've taken two pictures of the carbon fibre section, one with flash, one without and posted them below.

As the fractured U/C was returned I only have the pictures shown further back in the thread for comparison. It may just be the light but the cross section on the replacement does seem slightly darker than the original U/C.

MC

Edited By Steve Hargreaves - Moderator on 04/10/2012 17:13:30

[ken anderson.]

MC-i would say that the new one is the read deal.......you should have no probs with that one...

ken anderson ne..1 ...real deal dept.

[Ronaldo]

Tho' the thread is a few months old, I just thought I would add my 'tuppence' worth ...

I know of fellow modelers who have had 'carbon' undercarriages from 'Carbon Copy' failing on heavy/bumpy landings. On inspection the layers of fibres were delaminating at the stress points where the bend is as it curves away from the mounting plate to the leg itself, and as mentioned in an earlier post this also was in fact a 'sandwich' of a single layer of carbon fibre top and bottom, with ordinary glass fibre sandwiched in between. This wasnt obvious to the eye untill it delaminanated, and we pulled apart the laminations. At first glance when new it appeared to be solid carbon which it obviously is not, so beware !! they were sold as 'Carbon' with a 'carbon' price tag ! Possibly they may have put this right by now, I dont know, as I refuse to have one from them, but would be worth checking out with them if they are 'solid' carbon first as it cost my mate a time consuming model repair job when his undercarriage failed.

I fly 100cc + size models with 'solid' carbon undercarriages that came with the kits, and never had one fail ... yet. As someone mentioned earlier probably one would have to pile in and destroy the model before the 'solid' carbon undercarriage would break !! ( but i'm not about to test that theory in a hurry lol )

Regards.

[Phil 9]

Posted by Richard Wood on 03/04/2012 08:05:04:

Hi MC,

The fibreglass U/C fitted to the Wot 4 is certainly very tough & is available

for the Acrowot.

Mount it to the fuselage with two nylon bolts & captive nuts.

Nylon bolts will shear in a heavy landing, saving the model or U/C

from damage but are strong enough for normal landing loads.

I have experimented with nylon bolts and on bumpy grass tend to sheer off to often. now I beef up the u/c block by using glass cloth and epoxy to tie it to the model this makes it very strong. then I use metal bolts. this is a very strong setup. Anylanding heavy enough to break this is not a heavy landing its a crash.

[Bob Cotsford]

These are not even epoxy resin, CC admitted that everything is made using polyester. In my opinion that is the real problem. The last u/c I bought off them was listed as 'carbon composite' IIRC so maybe they've had their knuckles rapped by trading standards?

[Ben B]

Polyester resin and only the outer layer actually being carbon fibre? Hope they're cheap if so!

Isn't it possible to view the laminations by looking at the holes drilled for the undercarriage bolts? The new one looks much more like "proper" CF- I'd be sorely tempted to countersink the bolt holes (if this isn't done already) and have a sniff to see if it's polyester or epoxy...

[Aceflying]

Hi Guys, I honestly felt i had to sign up to this forum after seeing this thread.

It seems to me a fair few of you seem to be a little off with the real facts and i hate to see a fantastic company slated for peoples naivete of the actual products .

I have been buying undercarriages from Carbon Copy since they first began over 12 years ago and they by far out perform anything else currently on the market and always have done.

Just so a few of the facts are bought to light i wanted to point a few out myself:

Carbon Copy does not, nor has ever claimed their undercarruages are 'Carbon'. If you look anywhere on their own site or any of their retailers, they clearly say 'Carbon Composite'. The only actual carbon items they do (which are not composite) are the spats, cowls and canopys.

For those of you who obviously dont truely understand what 'Carbon Composite' actually is, let me enlighten you.

'Carbon Composite' is a strong lightweight material developed in the laboratory; where fibers of more than one kind are bonded together chemically.

If an undercarriage was made purely from Carbon it would have no flex in it what so ever. Carbon Composite is also used this way on full scale passenger airlines etc. Flexibility is needed on landings. If you asked them nicely im sure they could make you an undercarriage thats layer after layer of pure carbon, but as an undercarriage that would not work due to total zero flex on landings and the price would be sky high.

Someone has said they use epoxy resin or polyester resin. Totally incorrect. These undercarriages are not made with either. If you actually know polyester resin at all you would know that it would not bond the materials together correctly thus making it unusable.

The sadest part of this you seem to see the word Carbon and think that it means indistrucable. Any undercarriage can break and many factors are involved as to why it may happen. Is it not possible that the wrong undercarriage was purchased for the size or weight of the plane?

I have personally been a flying instructor now for so many years i cant even remember, i have 15 different planes........from previous experience an undercarriage will last as long as your own skill level allows it too. Even landing fairly gently on one leg at an angle (instead of flat) can cause fractures etc and the reason for this is simple. They are not designed to be landed that way. In the picture in this thread that looks exactly what has happened (admittedly i could be wrong).

Basically Carbon Copy are a fantastic company which i and thousands of other people will continue to use without problems for years to come. The main reason being their undercarriage are exactly what they say. 'a superior undercarriage made from carbon composite material' Like Ronseal- it does exactly what it says on the tin.

This was not put up to aim and fire at anyone, i just think it a great shame when only one side of the story is told and everyone is quick to join in and reload the gun.

Before anyone shoots me down........which i fully expect. No i dont make undercarriage but i do work with carbon fibre and resins so i do actually know what im talking about which is why i see all the putting down of a great company and their workmanship totally needless.

[Bob Cotsford]

"Someone has said they use epoxy resin or polyester resin. Totally incorrect. These undercarriages are not made with either. If you actually know polyester resin at all you would know that it would not bond the materials together correctly thus making it unusable."

I'm calling you out on this one - polyester doesn't bond the materials? Better tell Isopon and Davids who have been flogging us poly resin for use with glass cloth in car repairs.

A quote from an email I received from CC in answer to a query:

"I can also confirm your first guess is correct it is indeed polyester.
Kind Regards
*******"

[will -0]

Aceflying - aspects of your post are almost exactly the same, word for word as an email I recieved from carbon copy many years ago. Are you by any chance more than just a customer of theirs?

 

Personally, I think calling it "carbon" composite when it's mainly glass laminations is being extremely economical with the truth. Those that have carbon undercarts (eg the ones that weston used to make) will know that they are much lighter and yet are plenty springy. No doubt if you made a full-carbon undercart as thick as a Carbon Copy one, it would be very stiff, but you wouldn't need to would you?

 

After all, I could make and sell balsa core with carbon wrap u/c and sell it as carbon composite according to CC's rules.

As you'll no doubt be aware, "composite" materials are materials made from two (or more) different materials where the materials remain distinct in the final material (ie the final material is not homogenous). In fiber comosites this means the fibers (of which there may or may not be more than one type) and the matrix (usually epoxy or polyester resin). You do not need to have more than one type of fiber in a material for it to be a composite!

Edited By will -0 on 04/10/2012 16:05:07

Edited By will -0 on 04/10/2012 16:06:32

Edited By will -0 on 04/10/2012 16:07:02

Edited By will -0 on 04/10/2012 16:09:08

[will -0]

PS I have nothing against CC, you understand - I'm sure the products work fine, I just wish they were more up front with what they're selling as many many people will believe they are buying what they are not.

Maybe do it like this: says exactly what you're getting.

[Aceflying]

"I'm calling you out on this one - polyester doesn't bond the materials? Better tell Isopon and Davids who have been flogging us poly resin for use with glass cloth in car repairs."

A very valid point. Yes polyester will work with glass cloth. Glass cloth has different propertys to carbon fibre cloth, they are totally different materials and act in different ways. If polyester was to be used with carbon fibre, it would bond it together but would not be flexible enough or strong enough to withstand constant landings under weight without failing. This is the reason it is deemed as unusable for these items.

Despite what may have been said to you via email, as i have been buying from them years and live fairly local i have been to their factory on many occassions (which i may add is open for anyone to go and look around) and seen with my own eyes that they dont use epoxy or polyester .

Actually thats kind of a little white lie. They do use polyester but not on the aircraft side of the business. They also have a car body kit company on the same premises which they do use polyester and glass cloth for so i wont say they dont use it at all, just not in any of the model plane stuff.

As for being told its polyester, Yes its possible that you were told that but im 100% sure it would of been a genuine mistake by one of the office girls due to the fact to them (no offence) resin is resin. They dont make the stuff they just take orders and its possible for people to make mistakes.

I can tell you beyond a shadow of a doubt they do not, nor never have used polyester resin in udercarriages.

I have no interest in having a war with anyone, just wanted to put my point across.

[Aceflying]

Posted by will -0 on 04/10/2012 16:18:49:

PS I have nothing against CC, you understand - I'm sure the products work fine, I just wish they were more up front with what they're selling as many many people will believe they are buying what they are not.

Maybe do it like this: says exactly what you're getting.

i am not anything to do with Carbon Copy directly other than buying from them for many years and they have also helped me out in the past with many of my projects so i have spent many hours there discussing and playing with ideas with stewart.

By no means do i think your attacking the company yourself, but like i said before i personally think the stuff they make is great and its just a shame when some people are miss informed.

The only thing i dont agree with is no matter what you call it or how you dress it up, it is actually a carbon composite material. Those looking for a real pure carbon product should look for something that states it is. I could honestly see the problem if they were just calling them carbon undercarriages but thats not the case.

Taken from there website i think this is self explanitory:

We only provide two Material and Finish options.
'Voodoo' Our name for the Carbon Composite Product. Only available in Gloss Carbon Weave Finish.
'White Magic' Our name for the Glass Reinforced Plastic (fibreglass) Product. Only available in Gloss White Finish.

[Bob Cotsford]

ok Ace, no arguments but I am trying to understand as the CC web site has never been too informative. I use the cowls and U/Cs, and am not exactly a novice myself. It's not epoxy, agreed. The carbon composite is to all outward appearance a glass laminate dressed with a layer of carbon, and at least on the two most recent U/Cs I've bought, bonded with a sweet smelling resin coloured with black pigment.

The cowls have been straight glass with a sweet smelling resin coloured as per spec ordered. Not epoxy.

If the sweet smelling resin isn't polyester based, I'd be interested to know what it is. It looks like polyester, smells like polyester and works like polyester.

As for the delamination, I just accept that a composite U/C that has sharp radii at the top will suffer fatigue and will eventually delaminate at the fuselage exit 'bend' unless it's made using a more flexible resin. I've had it happen with kit-supplied units, CC units and others of unknown origin. I've never had an epoxy set of legs for comparison. Saying that, the CC ones on my Dragon Lady (9lbs) had survived for several years before they started to flex a bit too much for comfort and I expect the current CC ones to give several years service too. Same for my Skybolt (10lbs) and Extra (7-8lbs). Heavy landings will accelerate the process but if they're fit for purpose then they should survive the odd knock on a grass runway.

[sticky fingers]

Ace, just a quick few comments,or questions , if this company doesn,t use polyester resins, or epoxy resin ,what do they use?

Facts: Polyester resin is perfectly ok for GRP products, Epoxy resin is perfectly ok for GRP products

Epoxy resin is excellent for CFRP products

Polyester Resin is not a good resin to use with Carbon cloth

If a mixture of fibres e.g.cabon fibre and glass fibre are used in a laminate then epoxy must be used to ensure a good bond , choice of fibre orientation must also be taken into account,to ensure that stress points are suitably reinforced in the correct fibre orientation.The strength in carbon is along the warp in undirectional materialat at 0 degrees, and in a woven cloth at 0 and 90 degrees

Epoxy wil bond polyester GRP products but,polyester will not bond to CFRP well.

This only a small portion of info with regard to composites. Without wanting to be nasty ,I take exception to mis information being published on this forum with regard to any subject but particularly this, as I make my living having to know this subject

Dave

[Radge]

Fresh from the mould today, 9 layers of 200gsm bi directional carbon interlaced with 8 layers of 160gsm fibre glass. ZAP's best epoxy laminating resin used.

[sticky fingers]

nice one radge sounds like winner to me

dave

[kenking-King Design]

Can you please explain what the heck I'm looking at ? I'm sure it's very clever but it still looks like a mophead in an inverted bubble canopy. I'm sure it's just me ....

[Radge]

If you click on the photo Ken it'll enlarge buddy, you can then see the mould outline of the landing gear. Obviously I have to leave it 24hrs and then I'll trim the edges leaving a nice looking set of landing gear. Very strong and very cheap. Costed out at about £2.50 per set.

[Bob Cotsford]

Very nice Radge, I'll take one 380mm track, 150mm high for a 100mm wide fuselage please. £2.50 by Paypal ok?

[Radge]

Posted by Bob Cotsford on 07/10/2012 10:06:51:

Very nice Radge, I'll take one 380mm track, 150mm high for a 100mm wide fuselage please. £2.50 by Paypal ok?

Certainly sir! Tomorrow quick enough?(Resin is still a bit tacky)

[Bob Cotsford]

Did you use an existing U/C to make a mold from, or start from scratch?

[Ernie]

Hi guys, I'm thinking about making a carbon undercarriage for the TN lysander. From what I read above, is it better to use a composite, ie carbon, glass, carbon? Or should I use only carbon?

ernie

[Craig Carr]

Hi Ernie,

im thinking of making my own carbon undercarriages. I found this on the net, seems fairly straight forward:-

click here

Craig

Edited By Craig Carr on 11/10/2012 08:02:53

[Ernie]

Great Stuff Craig, exactly what I'm looking for. I'll keep you all posted when I get round to it

ernie