UK Lakester build G/GL

[Lemming Motors]

Drive (prop) shaft and a related rule book query.

I ordered a custom prop shaft last week and it is in my hands already - it is 15 inches long (nominal) with +/- 1" on the spline.

Rule 3s requires a sling of at least 1/4 x 1 inch - I will probably go much longer than 1 inch and enclose the entire front UJ through about 6" (as he very rear of my fuel tank could get clipped in a drop and whip.

Question: I will probably use 4.5" dia tube x 1/4" wall and connect that to the chassis with 4 struts in a cruciform that can be unbolted - should the struts also be 1/4" or could they be a shade lighter?

[manta22]

Could you just convert it to torque tube drive?

[Lemming Motors]

Neil - Interesting idea but too late for this build I think.

I probably do not need 6" of sling in truth - just enough to span the universal joint is probably adequate but I do not know how that would be viewed in tech - I am assuming the drop and whip is from a UJ coming apart so as long as the shaft is retained ....

In a parallel rule review - all traction bars and trailing links need a 1/4" sling but I don't recall seeing them on cars where they are inside the body work - was I just boy looking?

[bearingburner]

If the front universal comes loose you want to contain the thrashing around as much as possible.

[Jack Gifford]

The safest is a full-length (including both U-joints) of smooth/round-ID steel tube. So your choice is somewhere between that and the rules-requisite containment. I think my choice would be two loops- one just aft of the front joint and one just forward of the rear joint.

[jacksoni]

The safest is a full-length (including both U-joints) of smooth/round-ID steel tube. So your choice is somewhere between that and the rules-requisite containment. I think my choice would be two loops- one just aft of the front joint and one just forward of the rear joint.

Like this is I think what Jack is suggesting;

[Lemming Motors]

Would it be reasonable to assume that?s a door car so the drive shaft is running next to you or am I misinterpreting the pic?

Mines in a rear engine lakester so the drive shaft and I are not sharing space.

[jacksoni]

Actually is a modified sports and yes the driveshaft is beside the seat- ie my butt. But I understand with a rear engine lakester, I posted just to show what I understood Jack G was suggesting. Over kill for you but I have lost a driveshaft at speed and it is not a fun experience, wherever the shaft is. Your idea of two hoops is good.

[kiwi belly tank]

Putting a full tube over it will stop it from eating anything except it's self. Make it a two piece bolt together so you can take the top off for access. Build it as close as you can to the shaft so it can't flail around if it comes un-glued.
Question, are your U-joint angles equal?
  Sid.

[Jack Gifford]

Yes, Jack, your shield looks great. I'm familiar with that from pulling, where the shaft was between my legs (no U-joints, but 900 HP & 9,000 RPM).

[jacksoni]

Yes, Jack, your shield looks great. I'm familiar with that from pulling, where the shaft was between my legs (no U-joints, but 900 HP & 9,000 RPM).
[/quote In spirit of full disclosure, I didn't design or build it. But I do drive it!!!

[Lemming Motors]

I think I have found a source of 1/4" tube that is of an appropriate diameter but I have not figured out how to mount it as it will have to move with the rear axle in bump and rebound; as such something that envelopes the UJ at the gearbox end and an oval loop at the diff end might be my best approach - contain both ends but especially the gearbox end UJ so it does not molest the fuel tank (should it get dizzy and make a bid for freedom).

[Lemming Motors]

Rear axle push-rod location version 2.

Much better solution for several reasons than the original mock-up. It is not obvious from the pic but the bolt is supported by a tube that is attached at each end passing through the plate that reinforces the back of the upper 4 bar mount.

I am getting some oversize washers turned up in the shape of top hats - this will allow some rod end articulation (hat, 18mm) and be large enough diameter (rim, 30 mm) to retain them should they come apart - about 1/4" thick in total.

[kiwi belly tank]

Cut it in half & add pie shape pieces to oval the back for pinion travel & cross member mount it out to the chassis. Drop the suspension links, jack up the axle & the shaft can come out below the pumpkin or make the top a bolt on.
  Sid.

[Lemming Motors]

Thanks guys - I have found a suitable 1/4" tube and will slice and dice it - mmm - pie.

On an unrelated note - I cant find anything in the rules excluding medium density fibre board for the construction of fuel tanks.  cromag