rebelrider
|
| posted on 21/10/07 at 07:38 PM |
|
|
mcsorleys plans in ali ?
Is there any problems that anyone knows of with making book chassis out of 25 * 25 * 3mm ali boxsection ? as its half a kilo lighter per meter than 25
* 25 * 1.6 mild steel ?
im sat here with my fingers crossed because i started my chassis yesterday and now ive got a complete chassis i.e. fully fabricated and welded sat in
my garage made from ali.
|
|
|
|
|
mangogrooveworkshop
|
| posted on 21/10/07 at 07:45 PM |
|
|
Im off to get the popcorn
|
|
|
joneh
|
| posted on 21/10/07 at 07:49 PM |
|
|
http://www.locostbuilders.co.uk/viewthread.php?tid=36920
I think it ended in basically its fine if you want to die?
|
|
|
flange nut
|
| posted on 21/10/07 at 07:50 PM |
|
|
quote:
Originally posted by rebelrider
im sat here with my fingers crossed because i started my chassis yesterday and now ive got a complete chassis i.e. fully fabricated and welded sat in
my garage made from ali.
Never mind it might fall apart from metal fatigue, you work fast!
|
|
|
D Beddows
|
| posted on 21/10/07 at 07:51 PM |
|
|
That's quite impressive........ but have you tried a search on here for aluminium chassis?........not good...... 
|
|
|
StevieB
|
| posted on 21/10/07 at 07:54 PM |
|
|
Looking on the bright side, consider it a dress rehearsal before tackling the chassis again usinig steel 
|
|
|
Confused but excited.
|
| posted on 21/10/07 at 07:57 PM |
|
|
Obviously didn't work for Lotus, did it?
Just my two pen'th. 
Edit: Mind you, they glued theirs together instead of welding it.
[Edited on 21/10/07 by Confused but excited.]
Tell them about the bent treacle edges!
|
|
|
joneh
|
| posted on 21/10/07 at 07:57 PM |
|
|
I keep refreshing this page waiting for the sarcasm to flood in.
|
|
|
Confused but excited.
|
| posted on 21/10/07 at 07:58 PM |
|
|
It just has.
Edit; No flood, just one drip. Doh! 
[Edited on 21/10/07 by Confused but excited.]
Tell them about the bent treacle edges!
|
|
|
rebelrider
|
| posted on 21/10/07 at 08:35 PM |
|
|
oh f@$k
does anyone want a pretty frame to put on there mantle piece what a waste of 10 hours grr.
now do i ignor everything and go for it like a stubern idiot or restart now ?
and if i do it and sva it and it breaks can i put all the bits on a steel frame when no one is looking ?
|
|
|
zilspeed
|
| posted on 21/10/07 at 08:56 PM |
|
|
Aluminium monocoque - yes
Aluminium honeycomb planks like a formula vauxhall lotus - yes.
Design specifically intended for aluminium extrusions with cast nodes like an Audi A2 - yes.
Design intended for steel tubing.......
Nooooooooooooooooooo........................
All the best
|
|
|
tegwin
|
| posted on 21/10/07 at 10:07 PM |
|
|
IMHO, not the brightest idea...
Got any pics of this piece of ali art?
|
|
|
Peteff
|
| posted on 21/10/07 at 10:26 PM |
|
|
Weld an aluminium skin to both sides of it ?
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
kb58
|
| posted on 22/10/07 at 01:53 AM |
|
|
Normally I'd say there's a million ways to do things and that you should do what you want. HOWEVER, I cannot do that in this case.
Just build a steel one. If you really, really must do aluminum, consider a *properly designed* monocoque, having an airframe engineer or equivalent,
design it.
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
|
|
|
short track 123
|
| posted on 22/10/07 at 08:30 AM |
|
|
I know it's mostly in the design but if the welding is good could it be that bad?
rebelrider has used 3mm box wall so stiffness will be improved over 1.6mm of the same material.
May be some well designed bonded ally gussets over the welded joints going past the heat affected zones (see Photo )
http://locostbuilders.co.uk/photos.php?action=showphoto&photo=9image002.jpg
And ally has also been used in bike chassis ( Welded and Bonded ) for years and these are designed to flex.
Ally skins both side of the chassis would be a good idea but bond them instead of welding them no HAZ from the welding.
Just some idea's not saying it's right or wrong but just food for the mind.
Jason
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
02GF74
|
| posted on 22/10/07 at 09:30 AM |
|
|
funnily enough, last week I was thinking there hasn't been a "can I make chassis from aluminium" post for a while, lo and behold
there is!!
(ps I also asked this when I was much a newbie  )
a twsit would be can I make the chassis from carbon fibre?
|
|
|
Peteff
|
| posted on 22/10/07 at 09:38 AM |
|
|
used in bike chassis ( Welded and Bonded ) for years and these are designed to flex.
No they're not, that's why they have suspension. Aluminium bike frames have all manner of reinforcement inside the spars and on the swing
arms to stop them from flexing.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
jkarran
|
| posted on 22/10/07 at 10:00 AM |
|
|
I thought a certain amount of lateral give in rear swing arms was normal and desirable since the suspension can't really cope with vertical
wheel acceleration when you've got your knee down in a bend. I could of course be wrong.
jk
|
|
|
martyn_16v
|
| posted on 22/10/07 at 10:10 AM |
|
|
quote:
Originally posted by rebelrider
and if i do it and sva it
It'll fail. SVA testers tend to be a bit unsure of even properly designed ally structures, this they'll fail straight off.
|
|
|
caber
|
| posted on 22/10/07 at 10:44 AM |
|
|
As you have got this far why not figure out how to plate it by bonding and riveting then ask your local SVA for comments. Fatigue risk is an issue I
have a welded ally bicycle frame and it has cracks in the headstock, no one will go near fixing these,
Just a thought you may be able to use something like Lumiweld to put the panels on, this is a brazing technique with an aluminium alloy that melts
below aluminium melting temp but gives a structural strength joint.
10 hours is very quick I presume you have not got all the triangulation in yet? If you plate and fillet with reasonable thickness alloy you may be
able to omit quite a lot.
Failing this there will be some sucker on ebay who will take it off your hands probably for a lot of money!
Caber
|
|
|
Werner Van Loock
|
| posted on 22/10/07 at 11:06 AM |
|
|
Might wanna talk to this guy:
http://www.geocities.com/MotorCity/7630/chassis.html
It got thru SVA and is still on the road. The only difference with book chassis is that he glued honeycomb sandwich plates to the chassis to get the
torsional stiffness required.
You must also understand that if the chassis is very light and you add a light engine like a bike engine, that your overall weight will be very low
thus resulting in (much)lower stress on the chassis compared to a steel chassis with car engine where it was originally designed for.
And his car was using heavy sierra parts and DOHC engine, so using escort/cortina (alloy) parts and Bike engine with lightweight body (he used a very
heavy form of body) you should end up somewhere around 400kg? Or even less?
[Edited on 22/10/07 by Werner Van Loock]
http://www.clubstylus.be
|
|
|
short track 123
|
| posted on 22/10/07 at 11:07 AM |
|
|
All Bike Chassis flex ( and car ) ally or steel even if they are designed to not
Tul-aris is a prime e.g this even has parts of the rear suspension designed to flex ( it is now patented ) and has been used for a few years with no
problems this part is Ti but the same facts apply
http://locostbuilders.co.uk/photos.php?action=showphoto&photo=exotic-1.jpg
Put simply 2 Chassis of the same design made of 2 different materials will behave differently due to different Material behavior. You can make a
chassis too stiff so much so that the tyres will not cope in this case flex in the chassis is a good thing.
"Frame stiffening as discussed will in most cases significantly reduce the stress levels in frame members as well as stiffening the whole
structure, but there are occasions where the stiffening of one part of the frame may lead to increased risk of failure in another unstiffened area. A
flexible frame acts as a spring and can absorb and reduce the effects of some types of loading, if only parts of the frame are stiffened then we may
pass more load through to the unstiffened areas which may deform locally more than before even though the whole frame deforms less. Well, now you have
a rigid frame to work from, but that's all it is at the moment. Handling will probably have improved somewhat already but to get first class
results you must start the fine tuning process. That is, selecting spring rates, matching tyres, changing geometry by moving the fork sliders in their
yokes, etc. the list is endless. But that is all another story" A Quote With Thanks To Tony Foale
If it don't bend it will..........
Any way it's what make it all so fun different ideas and people willing to try different stuff. If we all stuck to the same ideas we would all
be driving/riding the euro box
Jason
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
rebelrider
|
| posted on 22/10/07 at 07:56 PM |
|
|
quote:
If it don't bend it will..........
Any way it's what make it all so fun different ideas and people willing to try different stuff. If we all stuck to the same ideas we would all
be driving/riding the euro box
Jason
...and for this reason the Ali frame lives..... gussets to re-enforce all joints, and a skin should do the trick, it was always going to be a BEC
anyway, so not quite so much stress weight wise. And if it doesn’t work ill make another, material costs me next to nothing and it doesn’t take long
to knock a frame up when you have all the correct tools, ill finish the chassis off this weekend. And take some pics for all to see.
I’ve never liked being a sheep i.e. doing as others do.
So… wish me luck or laugh at me either way the Ali chassis lives another day.
Watch this space……
|
|
|
907
|
| posted on 22/10/07 at 08:16 PM |
|
|
If I may I'll add my 2p
When aluminium is rolled into a sheet or extruded into a shape (i.e. box section) it gains it's strength from being work hardened.
When it's then welded it is annealed back to it's soft state and the addition of gussets just moves the soft area further along the
section.
This local annealing could be why the rungs of extension ladders are never welded in.
Paul G
|
|
|
Peteff
|
| posted on 23/10/07 at 12:00 AM |
|
|
the suspension can't really cope with vertical wheel acceleration when you've got your knee down in a bend
Even Rossi can't accelerate with his knee down in a bend I ride a bike and spend time at the bike shop and if there is lateral movement in a
swingarm it fails the MOT.
Jason, what is Ti? If it's steel then the same rules do not apply. Aluminium has a finite lifespan which is greatly reduced by flexing. The
quote you give there shows the benefit of stiff frame leading to more predictable handling because the suspension is able to do what it was designed
to do.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
.jpg)
