On page 98 in this months PPC.That does it for me, definitely going to reinforce the tunnel.
Not mine,on a Seven that Dave Walker had on his rollers, went through the side panels and hit his leg at 120mph On page 98 in this months PPC.
That does it for me, definitely going to reinforce the tunnel.
saw that have n't read thearticle yet though
its quite mad that it split in three and twisted to feck
Looked like it was made out of toffee.
What the feck causes them to do that? never heard of one twisting on a 1.5 ton Sierra! Scary? I think so
anyone know where i can see it?
I've just finished wrapping my prop up to send back to D&F to have the front section replaced after my fun at Coombe. Sounds like I got off very lucky compared to Mr Walker...!
I think I will do some thing with mine when I change the engine over the winter
this talk of props going is getting to often on the forum.
I don't read that mag, is his leg ok?
blimey...hope his legs ok...
i always give my prop a wee check these days after hearing the stories.
Another lesson in NOT making your own prop, best left to the professionals. Not that I'm saying it was homemade mind you...
Dave reckoned if there'd been a passenger they would have got it!
bit dodgy what hes saying about the compensation... yet another reason to take out the passenger seat 
The propshaft on my Mac was a disaster waiting to happen.
As I understand it the "knuckles" on the UJ at each end of the shaft should line up with the other. Well mine were fixed so that they were
offset from each other for some reason.
I have welded two upright bars on either side at the front and back on my transmision tunnel to hopefully take most of the force should my prop break. I am also getting mine done professionally (when i have some money).
Would a panel of Kevlar/Carbon instead of ally offer protection I wonder?
^^^ No!
Kevlar will probably do the trick in stopping any shrapnel but it wouldnt stop a prop. Carbon definatly wouldnt stop anything, in fact it would
shatter sending even more shrapnel your way........
That failiure looks well dodgy......
Propshaft failure scares me enough to take the tunnel top off and check after every weekend.
I had the rear section go (just on the output of the reverse gearbox), when (yet) another spindle snapped on the gearbox end of last year (whether the
spindle went first and then the UJ or vice-versa don't know). Fortunately on the downchange, entering Quarry, so slower than a lot of
opportunities, but the mess took a chunk out of my thigh nonetheless.
Only thing that really worries me now (having dumped the gearbox) is that the electric reverse assembly is now the obvious danger area. But don't
get me started on the MSA's insistence that I have such an assembly....
those pictures look bad, makes me glad now that mine stayed in the engine bay when it let go.
I read this in PPC last night, and he mentions that there was a lot of vibration from an "unbalanced wheel" during mapping, and that the
welds on the prop held up ok.
I suspect the vibration was far more likely the prop was already bent/unbalanced, and you can see the prop has failed right next to a weld in the
pictures.
Prop failures are almost unheard of in road cars, the only reason they can be failing in kit cars is faulty manufacture (unlikely if professionally
done) or incorrect installation e.g. not enough of the sliding joint in the gearbox, incorrect flanges, loose bolts etc.
Probably the same issue as mine would have had. With the UJs not lined up properly it causes the shaft to be unbalanced. Definately an "engineering" error on behalf of the builders.
quote:
Originally posted by iiyama
^^^ No!
Kevlar will probably do the trick in stopping any shrapnel but it wouldnt stop a prop. Carbon definatly wouldnt stop anything, in fact it would shatter sending even more shrapnel your way........
That failiure looks well dodgy......
quote:
Originally posted by livelee
Probably the same issue as mine would have had. With the UJs not lined up properly it causes the shaft to be unbalanced. Definately an "engineering" error on behalf of the builders.
quote:
Originally posted by twybrow
quote:
Originally posted by iiyama
^^^ No!
Kevlar will probably do the trick in stopping any shrapnel but it wouldnt stop a prop. Carbon definatly wouldnt stop anything, in fact it would shatter sending even more shrapnel your way........
That failiure looks well dodgy......
Where do people get this opinion from, that carbon fibre laminates are as brittle as a sheet of glass!? I make/develop primary aerospace CF parts, including test firing 8lb birds, travelling at several hundred miles an hour into the parts - you would be amazed at what a well designed composite part can withstand.
Is there any info on the car that was tested in the article? How much power / torque does the engine have? BEC or CEC? Home made propshaft or bought
from the kit manufacturer or a specialist?
Our prop worries me, too. We have a two piece propshaft, having a Quaife reverse. The front prop is short, but is angled quite sharply. The second
prop is the longer one to the diff. We did have loose bolts in the past, but noticed the vibrations and tightened with stronger Loctite. It seems fine
now, but I check every week...
Gergely
quote:
Originally posted by MikeRJ
quote:
Originally posted by livelee
Probably the same issue as mine would have had. With the UJs not lined up properly it causes the shaft to be unbalanced. Definately an "engineering" error on behalf of the builders.
I agree that is a very fundamental aspect of universal joints. A decent, professional propshaft manufacturer simply wouldn't make that kind of mistake.
quote:
Originally posted by twybrow
quote:
Originally posted by iiyama
^^^ No!
Kevlar will probably do the trick in stopping any shrapnel but it wouldnt stop a prop. Carbon definatly wouldnt stop anything, in fact it would shatter sending even more shrapnel your way........
That failiure looks well dodgy......
Where do people get this opinion from, that carbon fibre laminates are as brittle as a sheet of glass!? I make/develop primary aerospace CF parts, including test firing 8lb birds, travelling at several hundred miles an hour into the parts - you would be amazed at what a well designed composite part can withstand.
quote:
Originally posted by MikeRJ
I read this in PPC last night, and he mentions that there was a lot of vibration from an "unbalanced wheel" during mapping, and that the welds on the prop held up ok.
I suspect the vibration was far more likely the prop was already bent/unbalanced, and you can see the prop has failed right next to a weld in the pictures.
Prop failures are almost unheard of in road cars, the only reason they can be failing in kit cars is faulty manufacture (unlikely if professionally done) or incorrect installation e.g. not enough of the sliding joint in the gearbox, incorrect flanges, loose bolts etc.
Do we know what make of car the shaft was on?
Makes you wonder about the quality of the steel used? Cheap Chinese? Glad I had mine made by Bailey Morris , at least it should be decent
If the gearbox seized and the drive wheels kept turning would this happen?
quote:
Originally posted by jacko
If the gearbox seized and the drive wheels kept turning would this happen?
Eek - makes me more concerned about the one I'll have running down me leg to the front. As I'm a paranoid bugger, I've been
considering for a while retaining rings I've seen in drag racers etc. Seem to be popular stateside.
quote:
Originally posted by rusty nuts
quote:
Originally posted by jacko
If the gearbox seized and the drive wheels kept turning would this happen?
Unlikely IMHO . Can't say I've ever known a gearbox to sieze especially without warning
Very unpleasant.
I dont plan to use a DIY prop, but given that i am just completing my chassis and it is yet to eb painted, is there any mileage in adding a few more
stell tubes into the tunnel wall? Would this prevent it entering the seating area if it failed?
Simplest, cheapest, lightest and most effective way is to add a catcher or 2.
I made mine up mid build:
http://locostbuilders.co.uk/viewthread.php?tid=165585
quote:
Originally posted by twybrow
quote:
Originally posted by iiyama
^^^ No!
Kevlar will probably do the trick in stopping any shrapnel but it wouldnt stop a prop. Carbon definatly wouldnt stop anything, in fact it would shatter sending even more shrapnel your way........
That failiure looks well dodgy......
Where do people get this opinion from, that carbon fibre laminates are as brittle as a sheet of glass!? I make/develop primary aerospace CF parts, including test firing 8lb birds, travelling at several hundred miles an hour into the parts - you would be amazed at what a well designed composite part can withstand.
More than ten years back access to a suitable press I toyed with the idea of making the tunnel out of folded heavy gauge steel to act as a backbone but the access and weight issues put me off.
quote:
Originally posted by loggyboy
Simplest, cheapest, lightest and most effective way is to add a catcher or 2.
I made mine up mid build:
http://locostbuilders.co.uk/viewthread.php?tid=165585
I've had a prop shaft fail [my mistake - allowed the welds to be too thin] and the damage was significant, thogh fortunately not to me as the
prop catchers did their thing. If you look closely, apart from the scoring around the shaft at the hoops, look at the flattened the steel tube that
holds my fuel and wiring [adjacent the diff nose ] :-
quote:
Originally posted by coozer
Another lesson in NOT making your own prop, best left to the professionals. Not that I'm saying it was homemade mind you...
I had this happen on a Pilgrim Sumo a few years ago on the road. No real damage to the car as the thing went down into the road and just kicked the
back of the car into the air. I could see how that one happenned though as the prop was running at a wild angle as the diff (Mark 2 Granada) was
massively offset to one side, a serious design flaw.
Not expecting the same to happen to my MK ever though as the prop runs in a straight line.
....Not expecting the same to happen to my MK ever though as the prop runs in a straight line.
Hmmm... !
wot with a pinto ????
quote:
Originally posted by Not Anumber
Not expecting the same to happen to my MK ever though as the prop runs in a straight line.
prop failures in caterhams used on track are pretty common, at least in the higher power cars.
I have had a fair bit of involvement with an R400 racer and now a CSR, and we had two prop failures in each, with the last one in the CSR sending a
chunk of UJ through the alloy tunnel top and clean through the carbon dash as well, and severed two of the tunnel tubes. Failure occurred at
135-140mph at snetterton, when the flatshifter glitched and caused a transmission shunt on the straight, flat out!!
We've now upgraded to 3" diameter prop tube (by widening the tunnel), and gone for a much deeper insertion (ooh err missus) into the gearbox
that it had originally (well, originally with the Sadev box, that's not to say it wasn't deeper as supplied by caterham)
The combination of flatshift, straight cut sadev sequential gearbox and 290hp duratec seemed to break the stock prop pretty easily. This wasn't
tube failure though, it was shattering the actual UJ's
[Edited on 12/3/13 by NS Dev]
quote:
Originally posted by rick q
I've had a prop shaft fail [my mistake - allowed the welds to be too thin] and the damage was significant, thogh fortunately not to me as the prop catchers did their thing. If you look closely, apart from the scoring around the shaft at the hoops, look at the flattened the steel tube that holds my fuel and wiring [adjacent the diff nose ] :-
looking through my workshop last week , ive got a couple of prop catchers spare....
here's a pic of a prop failure I had..
[Edited on 12/3/13 by gavin174]
quote:
Noticed rick q's post above. That failure, at the rear flange, looks worrying. Not seen that one before.