designer
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| posted on 13/3/11 at 05:06 PM |
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Chassis layout finalised
Have posted a copy of chassis layout in archive.
Main longerons are of 50x50x3 and the chassis will be pannelled.
(Wish I had the time to learn Solidworks!!!!)
Comments
[Edited on 13-3-11 by designer]
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adithorp
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| posted on 13/3/11 at 05:15 PM |
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Triangulation?
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Kwik
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| posted on 13/3/11 at 05:21 PM |
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and the role hoop will do nothing if it isnt supported...
if your using a low power engine i wouldn't think you would need too much triangulation in the rest of the chassis...
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designer
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| posted on 13/3/11 at 05:35 PM |
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Triangulation should not be needed because of the size of the longerons (50x50x3), also the bottom will be panelled and the side panels will be
aluminium ducting.
The roll bar will be braced by the bike chassis.
The bike will be mounted at the head, towards the top of the roll hoop, and at the bottom cross member, with the side extentions providing lateral
support.
This should work.
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MikeR
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| posted on 13/3/11 at 05:48 PM |
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I don't quite understand your steering wheel support, as i see it - its going to be at a really acute angle pointing towards the roll bar. If
you have a joint in it to make it go more 'backwards' then you need some metal to mount it off.
Also echo other posters comments about triangulation - although if you intend going for stressed panels then check with others how they've done
it.
Personally 50x50x3mm seems VERY excessive. 25x25x1.5 and a little extra triangulation will give you less weight and a stiffer chassis. If you're
going for bike powered, less weight will probably be appreciated.
(nb,no engineer, all views are based on writing crap on this forum for too many years. they have no engineering background).
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designer
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| posted on 13/3/11 at 06:10 PM |
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quote:
(nb,no engineer, all views are based on writing crap on this forum for too many years. they have no engineering background).
Same here, not a trained engineer like my dad, just a happy tinkerer.
The steering rack is mounted on the upper front cross member and the column is supported under the dash hoop. Admittedly the hoop is well forward, but
it also is the support for the single spring/damper unit.
I want a simple to build, multi-tube chassis, not a spaceframe, I think that 50x50x3 is needed as a 'main' beam as it also supports the
bike laterally. But, I have though about going to 50x50x2 for the lower rail.
Many thanks for peoples comments.
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iank
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| posted on 13/3/11 at 06:32 PM |
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Given it's a tadpole 3 wheeler - a point I suspect many who go in through the front page will miss - and thus subject to almost no twist
compared with a 4 wheeler I suspect that a ladderframe chassis made from 3mm 50x50 will be more than strong enough (Spitfire chassis is a lot less
stiff than this design for example). It won't win any points for subtlety but I can't see it falling apart.
When you look at most of the 3wheeler chassis out there you'll see they use 25mm steel but also miss out triangulation.
Here's a Pembleton for example.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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Ratman
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| posted on 26/3/11 at 09:45 PM |
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I'm not sure about torsional stiffness and the three-wheeler. I built a very rough reverse trike with engine at the front driving the single
rear wheel a-la Morgan. When cornering it twisted a lot! The reason was that the weight on the rear wheel, although not a lot, is quite high above the
ground contact point of the rear wheel. So on cornering the moment couple going forward is significant. Triangulation only helps this if there are
closed four-sided pyramids built into the scheme of things. Just doing the sides of the car helps, but it isn't enough to get the full benefits
of triangulation. Its like, when you finally close the loop, you suddenly get the final 90% of potential stiffness. For the open top vehicle, three
tubes down each side, triangulated to make three planes is the perfect solution. Actually just down one side would do it. The problem is to find light
enough material to do it with.
The saving grace seems to be that a bit of twist in a three wheeler, although it looks awful, doesn't seem to affect the handling the same way
as it would a 4-wheeler. But I just like the feeling of a really tight car that can just shrug-off any rough road surface or violent maneuver with
disdain.
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