I have been looking at some of the latest setups and have found that oval tube is being used more on wishbones than box or round.

Why...???

I have found a source of oval tubing but wondered what the difference is in yield strengths between it(oval) and square or round for instance.

Any ideas on the subject????????

try reading this, lots of deatail

http://locostbuilders.co.uk/viewthread.php?tid=12587

[Edited on 10/5/2004 by I love speed :-P]

Have to agree with that I tend to spend a few hours a week just reading through old threads and bookmarking those i think may be usefull , try the above link for an interesting discusion on wishbones and yield strengths also try the search function

[Edited on 10/5/04 by Screwy]

I believe the primary benefit from oval tubing is reduced drag, not structural strength.

Reduced drag!

Thats going to the extremes isnt it? it will be reconstructive aerodynampic drag reducing facial plastic surgery next

Get rid of that bloody great hole in the front of the nose cone as the first attempt to reduce drag.................keep a keen eye on the temerature guage if you do though!

quote:

---

Originally posted by leto
I believe the primary benefit from oval tubing is reduced drag, not structural strength.

---

I agree with Steve, it just lets you use a larger tube without it looking clumsy, provided of course that you put the major axis front to back...

I'm using 22mm x 2.64mm wall round section and it's fine in my opinion. The oval section GTS Tuning wishbones look very nicely made and are acknowledged by many to be a good design.

Bear in mind if you stick with standard mounting points then you can always change wishbones at a later date if you are unhappy with what you get initially.

Cheers,
Craig.

Yes, its a larger tube but you don't get very much structural bonus from it. But I agree with Steve, it looks grate

Cheers
Leif

Can you tell us what the source is or is it secret

Dan.

Simple source for good quality round (not oval) tube is seamless hydraulic tubing. This is good quality, not too pricey and pretty easy to get hold of. Pretty pointless worrying about the yield strength of the tube when you are going to weld it anyway and totally change it's properties around the weld.

NS Dev, development engineer at seamless steel tube rolling mill.

Frankly, I don't see much aerodynamically wrong with the big hole in the front of the locost, depending on how its used. Afterall, properly routed radiator exhaust can be used beneficially, and there is excess capacity there if you wanted to route air directly to important areas....intakes, exhaust manifolds close to body work, etc. Oh yeah, this is about oval tubing....umm, cool stuff, probably just as stiff in bending as round tube of same cross section (height wise). Don't know if it'll increase top speed though, kind of frivilous. Did I mention it looks cool?

The "big hole" in front of the locost is'nt exactly a big hole,it's a big hole blocked off by a radiator.Try to hold that radiator outside your window driving at 60 mph and you will notice immediately the drag such a small surface can create.
Oh yeah you... are talking about oval tubing for wishbones, oval tubing is probably stronger,compared to round tubing,under breaking.

I'll grant there is a big radiator in that large hole, but if you blocked off the whole, you'd still be dealing with the same frontal area. Versus hanging it out the window would increase the overall area. Not to mention ducting the radiator exhaust into the upper cowling can help contribute to increased radiator flow efficiency, as well as reduced lift on the front end. Not to mention you don't end up shooting hot air directly over the hot engine. Often times internal flows are just as important as external ones.

Hilmar tubes in Manchester is an absolute goldmine of profiles - round, square rectangular, oval in ERW, CDM you name it!
huge place

http://www.hilmar.co.uk/

mail then for a list

in my humble opinion, the big gaping style less hole in the front of a 7 type car is what letds the whole thing down.

It looks a bit naff. Most cars have the front and rear as a major styling feature - a 7 type has basically an open tube at its front. The rest of the car look good as a simple styling excercise, but the front doesnt work for me. Just look at the luego banner ads, at the orange car , for example.


its all in the eye of the beholder, but I recon the front of this looks great......
Rescued attachment prowler.jpg

That front indeed look's great and probably will have the same airflow benefits,if not better,and it will reduce frontal drag significantly.

I am using the front similar to the marlin sportster, not as aero as the last post but smoother than the seven nose.
Dale
Rescued attachment small marlin.jpg

Another advantage of oval tube is that it is aeasier to weld in ends to take staked in spherical joints.

It is actually theoretically possible to get thrust from a properly designed radiator duct. The thrust coming from the heat energy.

Basically you have an opening approx .3 to .25 the area of the radiator, a duct expanding at a maximum angle of 14 degrees (any more and the air flow becomes detached) to the radiator. This expanding duct slows the air flow so it can absorb more heat. After a radiator you then require a converging duct to speed the air up again before it rejoins the outside air.

Other small points are radiused entries to the duct for when the vehicle is in yaw.

JB

Hello John! This is Nat, how did you get on at Shelsley, just to go completely off topic!!

Smartie boxes covered in sticky black plastic would be stronger than some 'bones i have seen..!

Another product of the Blue Peter watching generation?

The airflow in the noscone is a chaos with all the tubes,radiator, hoses etc...so it would be very unlikely that any "thrust" can be gained.The temp diff before and after the radiator is way to small and has to many "leaks" to built up any pressure for the air to be accelerated and form "thrust".There would be not enough room left for a radiator when the nose cone of a 7 would be made to have internal boundary layer characteristics.

Aaaah Steve the Plymouth prowler now that is the ultimate 7 clone, its bleeding beautifull.
Cheers,
Bob