russbost
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| posted on 9/1/12 at 11:23 AM |
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Making a composite spring???
Ok this isn't directly car related, but could be as you could make car springs the same way
I have a small Permit aircraft - a Pulsar, the tailwheel spring sticks out of the rear of the fuselage as a cantilever & the tailwheel is bolted
thro' it. In their wisdom, they decided to make this leaf spring from composite materials, I don't know exactly how it's made , but
would imagine it is some type of linear fibreglass strand in layers, bonded with some form of epoxy. I would like to replace this spring as mine is
starting to delaminate, other repair procedures are possible, but I would prefer to replace if i can.
Unfortunately the spring is no longer available from the manufacturer, so I need to get one made. Does anyone on here have experience of such a thing
or can point me at someone who has? I've done the usual Google searches, but it's only bringing up big companies, who I very much doubt
would be interested in my tuppenny halfpenny one off!
The spring doesn't have to pass any special tests as this is a Permit aircraft & providing it is man enough for the job & I & my
inspector are stisfied with the repair it can be signed off. Perfectly happy to pay reasonable money to get one made, but don't want to pay the
earth for something which, at most, represents a couple of hours work & a few quid in materials!
Any suggestions/info welcome.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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designer
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| posted on 9/1/12 at 11:51 AM |
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Are there any companies that make composite springs?
If so, I would contact then and as if they have an 'rejects' they could possibly take a slice off.
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HowardB
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| posted on 9/1/12 at 11:52 AM |
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good morning,
I would start with an indication of how big it is, and then perhaps a drawing/ picture.
Simple grp/epoxy is not too difficult, if it small then it may be possible to create something kitchen table top.
hth
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again  and goes zoom)
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twybrow
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| posted on 9/1/12 at 12:06 PM |
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You would typically need to use a closed mould rpocess, with matched tooling - typically RTM is used.
How to design and manufacture a
composite spring - This articale gives a step by step on how to make them.
For braided materials, contact Eurocarbon in the Netherlands (if you do, let me know and you can name drop me, and I am sure you will get plenty of
free samples).
A scientific paper on design and manufacture here...
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twybrow
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| posted on 9/1/12 at 12:07 PM |
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quote:
Originally posted by designer
Are there any companies that make composite springs?
If so, I would contact then and as if they have an 'rejects' they could possibly take a slice off.
If you actually told the supplier what this is for, no one would give you an offcut to use directly....!
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HowardB
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| posted on 9/1/12 at 12:56 PM |
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quote:
Originally posted by twybrow
You would typically need to use a closed mould rpocess, with matched tooling - typically RTM is used.
How to design and manufacture a
composite spring - This articale gives a step by step on how to make them.
For braided materials, contact Eurocarbon in the Netherlands (if you do, let me know and you can name drop me, and I am sure you will get plenty of
free samples).
A scientific paper on design and manufacture here...
Agreed, rtm or full autoclave would be the best solution. However there are table top solutions to this, for example warm cure epoxy, mylar film and
home made vac bag. If the spring is parallel in section it may be possible to purchase just a piece of cuboidal grp. If it has pattern and shape it
will be a little more complex.
Local boat builders / technical collage or similar might be able to help,..
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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MakeEverything
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| posted on 9/1/12 at 01:07 PM |
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Here
$80 plus postage.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MakeEverything
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| posted on 9/1/12 at 01:08 PM |
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Or steel here;
http://www.aircraftspruce.com/menus/lg/tailwheelaccessories.html
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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russbost
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| posted on 9/1/12 at 01:22 PM |
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Thanx for all the info, the links refer to making coil springs tho' which is a bit different as they obviously have to be able to behave in
torsion unlike a flat leaf spring.
This is a very simple spring, haven't got exact sizes in front of me, but must be around 0.5m total length, tho' only around 250mm sticks
out of the fuselage, it's a rectangular "X" section approx 25mm wide x around 20mm thick, gets a little thicker towards the back end
where the tailwheel actually bolts thro' it. The weight on it is only about 20kg, you can easily pickup the whole backend of the aircraft with
one hand!
The links to aircraft bits don't have anything quite like it, again theirs all seem to be more complex, but I guess it may be worth talking to
them.
Where would I purchase cuboidal grp?
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Neville Jones
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| posted on 9/1/12 at 01:35 PM |
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You been talking to Scootz by any chance?
I can have a go at this, just give me a blank cheque if you're serious. That yank item for $75 is a steal, if it's what it is as it
seems.
Cheers,
Nev.
[Edited on 9/1/12 by Neville Jones]
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scootz
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| posted on 9/1/12 at 01:48 PM |
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quote:
Originally posted by Neville Jones
You been talking to Scootz by any chance?
I can have a go at this, just give me a blank cheque if you're serious. That yank item for $75 is a steal, if it's what it is as it
seems.
Cheers,
Nev.
LOL... no! Complete coincidence! I actually thought this was going to be a thread started by you Nev!
PS - Still scratching my chin! Will get back to you before the weeks out.
It's Evolution Baby!
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HowardB
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| posted on 9/1/12 at 02:59 PM |
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quote:
Originally posted by russbost
Thanx for all the info, the links refer to making coil springs tho' which is a bit different as they obviously have to be able to behave in
torsion unlike a flat leaf spring.
This is a very simple spring, haven't got exact sizes in front of me, but must be around 0.5m total length, tho' only around 250mm sticks
out of the fuselage, it's a rectangular "X" section approx 25mm wide x around 20mm thick, gets a little thicker towards the back end
where the tailwheel actually bolts thro' it. The weight on it is only about 20kg, you can easily pickup the whole backend of the aircraft with
one hand!
The links to aircraft bits don't have anything quite like it, again theirs all seem to be more complex, but I guess it may be worth talking to
them.
Where would I purchase cuboidal grp?
Companies like Tufnol, and others do sheet grp from which it might be possible to cut the correct shape / profile
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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lewis
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| posted on 9/1/12 at 04:04 PM |
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Does it not need a CRS? Or are the rules totally different for Permit aircraft? I would try a source the correct part 2 hand,could you not source one
through the PFA?
I am a driving god!..........sort of
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twybrow
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| posted on 9/1/12 at 04:34 PM |
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quote:
Originally posted by russbost
Thanx for all the info, the links refer to making coil springs tho' which is a bit different as they obviously have to be able to behave in
torsion unlike a flat leaf spring.
This is a very simple spring, haven't got exact sizes in front of me, but must be around 0.5m total length, tho' only around 250mm sticks
out of the fuselage, it's a rectangular "X" section approx 25mm wide x around 20mm thick, gets a little thicker towards the back end
where the tailwheel actually bolts thro' it. The weight on it is only about 20kg, you can easily pickup the whole backend of the aircraft with
one hand!
The links to aircraft bits don't have anything quite like it, again theirs all seem to be more complex, but I guess it may be worth talking to
them.
Where would I purchase cuboidal grp?
ah ha, sorry, I missed that vital piece of information (still, now you know how to make a helical spring in carbon!).
To make the version you need is much easier...! But you would need to be able to do the calcs to work out what stiffness, and therefore what
deflection you should be aiming for. That will help you calculuate the materials to use, the fibre direction, the thickness etc. My only concern would
be on designing for fatigue...
Have a look at the following paper:
Scientfic paper
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Neville Jones
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| posted on 9/1/12 at 05:12 PM |
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quote:
Originally posted by twybrow
quote:
Originally posted by russbost
My only concern would be on designing for fatigue...
Have a look at the following paper:
Scientfic paper
That paper referred to is about the only piece of research in this area available for the public.
I've been referred to a couple of research documents outside the public realm, and they are inconclusive.
The area of fatigue life on composites is being much researched at the moment, but no information is public.
The crucial element is that composites, and in particular carbon composites, are extremely sensitive to point loads, and extreme shock events, which
metals and plain plastics can absorb quite easily. The composite cracks, or microcracks which leads to the big ones.
A carbon(or any composite) leaf spring needs careful placement of fibres, and choice of fibres, then an extremely elastic resin to let it all bend and
rebound without cracking. Then it has to be able to do nth number of times before failure.
Cheers,
Nev.
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clairetoo
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| posted on 9/1/12 at 06:01 PM |
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If its any help , Vauxhall Mavano's have composite rear leaf springs - maybe you could cut a section out of one ?
Its cuz I is blond , innit
Claire xx
Will weld for food......
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russbost
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| posted on 9/1/12 at 06:42 PM |
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Having done some further digging on this I'm told others have repaired their composite spring by wrapping with carbon tape to stop any
delamination.
Any ideas on correct type of tape & resin for this as obviously has to be exceedingly flexible.
Re the durability & testing to nth deformation, that appears to be what they forgot on the original design!!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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twybrow
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| posted on 9/1/12 at 11:20 PM |
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quote:
Originally posted by russbost
Having done some further digging on this I'm told others have repaired their composite spring by wrapping with carbon tape to stop any
delamination.
Any ideas on correct type of tape & resin for this as obviously has to be exceedingly flexible.
Re the durability & testing to nth deformation, that appears to be what they forgot on the original design!!
Russ you will change the stiffness characteristics, and potentially make it more likely to fail - be careful!
As for resin, well really you would want to know what it is made from now. If it is carbon, it is almost certainly going to be an epoxy. Also beware
- epoxy will stick to polyester, but polyester will not stick to epoxy.
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spiderman
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| posted on 9/1/12 at 11:43 PM |
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I know of someone who does prototype composites (GRP/Carbon Fibre/Kevlar) projects amongst his everyday work and does a lot of work on military
projects. If you are interested send me a u2u and I will have a word with him to ask if he would be interested in taking on the job.
Spider
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russbost
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| posted on 10/1/12 at 12:51 AM |
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quote:
Originally posted by twybrow
quote:
Originally posted by russbost
Having done some further digging on this I'm told others have repaired their composite spring by wrapping with carbon tape to stop any
delamination.
Any ideas on correct type of tape & resin for this as obviously has to be exceedingly flexible.
Re the durability & testing to nth deformation, that appears to be what they forgot on the original design!!
Russ you will change the stiffness characteristics, and potentially make it more likely to fail - be careful!
As for resin, well really you would want to know what it is made from now. If it is carbon, it is almost certainly going to be an epoxy. Also beware
- epoxy will stick to polyester, but polyester will not stick to epoxy.
I want to change the stiffness characteristics! The spring never appears to have been man enough for the job in the first place, I've now found
that it seems to be a common problem - unfortunately on a fairly uncommon plane at least on this side of the Atlantic so there isn't a vast
knowledge data base to mine into. Basically if I can strengthen & stiffen the existing arrangement & stop it from delaminating then all will
be fine, it's not on the point of failing or anything like that, I just want to get it sorted b4 it deteriorates, but obviously any repair needs
to be very flexible as well as being strong.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Neville Jones
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| posted on 10/1/12 at 02:13 PM |
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quote:
Originally posted by twybrow
If it is carbon, it is almost certainly going to be an epoxy. Also beware - epoxy will stick to polyester, but polyester will not stick to
epoxy.
Not necessarily. Phenolics have been in use commercially since the turn of the 19th>20th century, and are still used in composites. It's
just that they are not common use for everyday composite mouldings.
Then there's the modified resins that aren't advertised, but can be had from Ciba and Shell, among others.
Cheers,
Nev.
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russbost
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| posted on 10/1/12 at 06:17 PM |
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Many thanx for all the input guys, it looks like I will probably go the same route as others with the same plane have done which is to beef up what we
already have with a carbon sleeve & suitable epoxy resin. Think I've tracked down the necessary gear now, all thanx to help received here -
this is still the best forum on the planet even if it's not quite as good as it used to be!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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twybrow
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| posted on 11/1/12 at 01:57 PM |
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quote:
Originally posted by Neville Jones
quote:
Originally posted by twybrow
If it is carbon, it is almost certainly going to be an epoxy. Also beware - epoxy will stick to polyester, but polyester will not stick to
epoxy.
Not necessarily. Phenolics have been in use commercially since the turn of the 19th>20th century, and are still used in composites. It's
just that they are not common use for everyday composite mouldings.
Then there's the modified resins that aren't advertised, but can be had from Ciba and Shell, among others.
Cheers,
Nev.
So my quote still stands. Almost certainly going to be epoxy (but a small chance it could be a phenolic, a viynl ester, ployester or many other resin
types!
And Phenolics haven't been used with carbon since the turn of the 19th century, as it didn't exist until 1940s (I know this, as my former,
now late boss was one of the early pioneers making it!)! 
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