26R Body Specification

[bill308]

I'm about to place an order for a bespoke or custom 26R body. Feedback from the community would be appreciated. The body is normally offered in 3 weights, road weight, light weight, very light weight. Lids are available in either road weight or light weight.

This specification covers a new, bespoke 26R body, including all lids and a windscreen surround.

1. The 26R body style will be LHD with wheel arches capable of accommodating 13 x 5 and 13 x 6 inch, KO or bolt on wheels, and 205/60R13 or 165/70R13 tires, at all four corners. Fiberglass will be light weight with local reinforcement of stress concentration areas.

2. The door aperture lattice shall be fabricated as normal, except it shall be make of stainless steel in its entirety, and an appropriate stainless steel welding rod/wire will be used. The truss design shall accommodate both standard RHD and LHD pedal boxes for alternate fitment.

3. Series 1 fixed head lamps with Perspex covers will be fitted.

4. Light weight, flat bonnet with reinforcement to resist distortion by the retaining front springs.

5. Road weight doors

6. Light weight boot

7. Road weight wind screen surround

8. The boot floor will be modified to accommodate a large bore, in line muffler.

9. The driver?s (LHD) foot well will be reinforced to better accommodate the Kelvedon balance bar, pedal assembly.

10. The passenger foot well, top panel, will be lowered to accommodate a larger cold air box, if necessary.

11. The passenger foot well and near wing cavity shall be further modified to accommodate a 2-gallon dry sump tank and its necessary fittings and hoses, while maximizing leg room. The dry sump tank design is open at this time.

12. Known stress concentrations, including the following, shall be reinforced with extra fiberglass or carbon fiber layer(s) on the unseen side.
a. All bobbins, especially where fixed to the chassis
b. Front corners of body door aperture
c. Head lamp openings
d. Cowl under windshield washer jets
e. Cowl under windshield wiper boxes
f. Rear deck boot hinge
g. Backside surface of Tenax fastener post locations and soft top rear deck clips
h. Door handle backside surfaces

Bill

[bigvalvehead]

Hi Bill
Who's shell are you getting?
Dave

[trw99]

Bill, it would probably be helpful if you were to give us an idea of what your intended use of this body is.

It is obvious you will be setting the car up for competition, but what type?

Tim

[bill308]

Wow, that was pretty quick feedback. Thank you.

The car is meant primarily for street use with only occasional track days. It will be fitted with a 2-liter, dry sump, alloy engine, a Stowe head, and an alloy T9 with custom gears. I'll fit a Safety Devices roll bar with side and wheel intrusion bars and all amenities.

I will likely purchase from Kelvedon. I've also talked to TTR and Miles Wilkins. As far as I can tell, they are all made by the same folks, just not sure who this really is.

Bill

[CBUEB1771]

Bill,
Do you have weight projections form the vendors you have spoken to? I am thinking primarily about the weight of the body shell itself. The TTR website shows about an 11 kg difference between the light and very light versions but no figures for the standard weight shell. The Kelvedon site is purely qualitative about weight. I just wonder if the reduction in weight from the standard road version will be worth it given your intended use. Your end product is going to have a pretty impressive power to weight ratio regardless of the body shell version you select. I think that increased flexure of the lighter weight shells might not be a desirable trade-off. I noticed that Kelvedon has an aluminum floor stiffener for the seat mounting area. That might be a good add-on for a lighter weight shell.
Russ

[bill308]

Hi Russ.

Thanks for your thoughtful feedback. Got much snow?

Kelvedon reports weights for the bare body of 75 (with lattice), 55, and 40 kg respectively, for the 3-weights.

My analysis shows each lattice to be about 3.7 kg assuming the perimeter rods are 0.375 inch diameter and the triangulation is 0.20 inch diameter, mild steel rod.

Presumably, the two lighter weight versions are supplied without lattice support around the door aperture.

Without the lattice strengthening, one looses an outboard seat belt pickup point, a standard pedal box pivot point, and inner sill lip, door pivot, and door latch support.

I plan to install a Safety Devices roll bar with the side (sill) and wheel intrusion bars. This bar can be used to support an outer seat belt pickup point by welding a tab in the appropriate location. The sill bar can be tied to the sill by a series of saddles glasses into the sill and the open face closed with a bonded or otherwise fastened flat panel. These measures will add back some weight saved by omitting the lattice in the first place.

The sill bar could also provide an outboard pickup for a floor stiffener.

I'm starting to lean toward a non lattice body, unless it can be made in stainless steel. In my mind, the use of mild steel is a bad material choice for anything embedded in fiberglass due to corrosion concerns.

Bill

[CBUEB1771]

Thanks for your thoughtful feedback. Got much snow?

Snow? What snow? You aren't that far away!

In my mind, the use of mild steel is a bad material choice for anything embedded in fiberglass due to corrosion concerns.

Living in New England we are well aware of what rusting carbon steel reinforcing rod does to concrete, I agree with you. Making the lattice in stainless steel should be no problem, vendor attitudes aside. Replacement Elite body shells have been available with the various metal inserts made in stainless rather that carbon steel. It sounds as though you have then thinking through issues in good detail but don't give up on the stainless lattice too quickly.

[bigvalvehead]

Hi Bill
Both Kelvedon and Miles' shells are made by Boss Motors or A1 bodyshells as they are also known.

The TTR shells are made by a guy who does a lot of Formula car work with carbon fibre.

I know someone who has a shell for sale at the moment, from Boss, that he wasn't particularly happy with.

The TTR shells are expensive but less work to panel fit etc.

Cheers
Dave

[bill308]

Thank you Dave.

I also noted that TTR's body was considerably more expensive than Kelveden and Miles. When I spoke to Miles he seemed to indicate that he made the bodies on his original molds. Later, Kelveden indicated that Miles did not make his bodies, although they talk to each other regularly. Lee Chapman, a race car supporter on the USA east coast, indicated Miles made the bodies for all the other guys. So, lots of conflicting information swirling about.

Is the major objection to the Boss or A1 body shells the panel gaps, or is it much more? For a street car, panel gaps and general appearance are very important to me.

Best regards,
Bill

[batfish]

Hi Bill

I have not seen any light weight body shell that has not got the lattice installed, I always thought it is vital to the strength of the body shell.
The Safety Devices roll cage has threaded anchorages for the seat belts built in.

Regards

Andy

[bigvalvehead]

Boss Motors has original moulds from the factory. Actually moulds that were scrapped and reclaimed) I have factory Europa moulds that have had sections cut out with a disc cutter!!
They make shells for Miles and Kelvedon.

The lightweight shell comes without side wires.

The TTR lightweight has steel side wires his super light has alloy side wires.

I know another guy who makes excellent shells but lead times are crazy. see pic

[bill308]

Hi Andy.

I suspect the light weight bodies are generally supplied with out the lattice. There are at least 2 reasons for this.
1. My analysis show each lattice weights about 8 lbs. Omission of the lattice saves about 16 lbs.
2. Absence of a lattice facilitates the installation of sill intrusion bars or a roll cage.
Absence of a lattice leaves the inner lip of the sill unsupported unless dealt with in another way.

My Safety Devices roll cage has no provision for seat belt anchorages. It was purchased about 10 years ago. I see the current Safety Devices online drawing shows bolt holes that are presumably for seat belts.

Thanks for the photos Dave. Who's the mystery guy that makes the bodies? For the street, I want a stainless lattice. If the perimeter, 3/8 members could be made of thick wall, stainless, that would save some weight and be a plus. Mild steel embedded in fiberglass and exposed to moisture is a recipe for corrosion, a bad design decision. The incremental cost of 16 lbs of stainless is small relative to the potential grief of rust. The selected alloy should be easily weld able and corrosion resistant.

Bill

[john1180]

I've always thought a sandwich panel of 5mm okume marine plywood with a light fiberglass cloth and epoxy on either side would be reasonable replacement for the metal frame. When glassed into the body it would make the sill area very rigid with very little weight. You could drill 2 or 3 inch lightening holes once it was in place.

[bigvalvehead]

In the past I have removed the lattice when rusty and boxed the sill area in with glassfibre sheet. after fitting the side bars the area can be foam filled for added rigidity.

Welding a boss for the seat belt mount would be easy and bonding in a mount for the pedal box should also be ok.
cheers
Dave

[gav]

When I did my sills I removed the rusted lattice, fitted the side impact bars from the inside and bonded in the ply with mat and grp that soaked into the ply. I pre cut holes in strategic places to access door gear, bolts for side impact frame etc.
It worked really well and the sills are now very stiff.

Gavin