ned
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| posted on 31/1/06 at 09:51 AM |
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Nice 
so, what size prop should i get then guys 
[Edited on 31/1/06 by ned]
beware, I've got yellow skin
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Syd Bridge
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| posted on 31/1/06 at 10:00 AM |
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If it were not rotating, the biggest diameter wins the argument.
BUT...rotating inertial mass has to be taken into account. (You lighten a flywheel at the periphery, not the centre, for greatest effect.)
So, the smallest diameter is preferable. BUT... then you get into whirling and whipping frequencies. The design compromises are many.
With the short length of a Locost prop, I'd go for the smallest diameter I could get away with, and maybe a slightly heavier wall. But
that's just me. 
Then again, I know a man who makes these things out of carbon fibre. 
Syd.
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NS Dev
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| posted on 31/1/06 at 10:00 AM |
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heh heh!
If a 3" will fit, use that, if not use a 2". As I said, a 3" prop won't really fit if you have a gearshift extension (similar
to the westfield one)
Caterham-Vauxhall HPC used a 2" one, which is what I am using.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Fozzie
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| posted on 31/1/06 at 10:02 AM |
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quote:
Originally posted by ned
Nice
so, what size prop should i get then guys
Tee-hee, sorry Ned, a 'senior moment' with memories there!......
I still maintain, given the shortness of the prop, that a good quality 2" will be suffice, but get it balanced.....
Thats my two pennyworth anyway....
Fozzie
BTW my donor was a mk2 escort, that prop was also 2".......
Absolutely Syd....totally agree.....
[Edited on 31/1/06 by Fozzie]
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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ned
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| posted on 31/1/06 at 10:41 AM |
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So to recap:
prop should be rated for 280-300bhp / 200lb/ft
prop length 25" (approx 624mm)
suggested diameters 2" or 3" (one manufacturer mentioned 2.5" )
suggested wall thickness 2mm
1300 series uj's
[Edited on 31/1/06 by ned]
beware, I've got yellow skin
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NS Dev
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| posted on 31/1/06 at 10:54 AM |
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PS Ned, cut that seamless tube for your steering column, just got to find a way to attach an address so the postie can read it!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 31/1/06 at 11:01 AM |
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ta muchly Nat.
beware, I've got yellow skin
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garage19
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| posted on 31/1/06 at 12:26 PM |
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When i ordered my prop from autoprop they recommended a 3" item for my 270-300bhp indy. By the time you added vat and carriage it was nearly
£150.... but it is very well made. A little over engineering on something that spins that close next to your legs is not a bad thing!!!
A friend bought a carbon fibre prop for his 300zx from a company in the states who also make them for the indy cars. It cost him £1400 
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JB
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| posted on 31/1/06 at 04:56 PM |
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Props
Sorry for being a bit late on this one.
I used to work for one of the Uk`s leading propshaft firms and have made 100`s of shafts for kit cars, rally cars and racers.
Tube thickness. Tube thickness will have a bearing on the strength of the prop. But parts to build props come in standard sizes. For 2" tube you
are looking at 0.064" or 0.095" wall thickness. Any thing else will require non standard tube yokes and tube.
For a prop you describe I would not fit a 2" x 0.095" tube prop to my vehicle. It may be OK but I would fit 2 1/2" tube.
The other thing you could specify is DOM tubing instead of welded. Most prop tube for cars is actually seamed ERW. Do not use CDS as the wall
thickness is not consistent enough.
One other point I found out from experience. If the prop is well made it should hardly have any balance weights on it. One about the size of a 2 pence
piece maximum.
John
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chrsgrain
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| posted on 31/1/06 at 06:16 PM |
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Hi all,
I'm not yet a the stage of needing a propshaft, but I had thought about the price.... Dax quote £125 ex VAT for a standard Ford to Ford one
(which sounds roughtly right ish) but want a whopping £287 !!!! for one to connect an omega box to the standard sierra diff.... Has anyone ANY idea
about the price differential at all - seems a lot - and can anyone suggest some people to ask for quotes.
Thanks
Chris
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ned
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| posted on 31/1/06 at 06:19 PM |
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http://www.propshaft.co.uk
http://www.propshafts.co.uk
http://www.autopropuk.co.uk/
http://www.baileymorris.co.uk/
beware, I've got yellow skin
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chrsgrain
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| posted on 31/1/06 at 06:22 PM |
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Cool..
Thanks Ned
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JB
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| posted on 31/1/06 at 08:46 PM |
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Omega Box
Does the Omega box have a rubber guibo (donut) on the it? If so then this is the reason for the big cash as you will probably require a special
adapter.
John
PS I used to make all the props for Dax.
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chrsgrain
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| posted on 31/1/06 at 09:11 PM |
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Yes it does - that'll be the reason then 
Anyone you'd recommend then??
Chris
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