DB1 Front Crush Structure

[R. Pare]

I'm looking for a slower deceleration more than any physical protection.... Michael

You won't get any slower deceleration via the nose box without making it any longer - the effective crush space ends at the leading edge of the MC, and once you hit them, all bets are off as to how far the frame will collapse into your legs. You are deluding yourself if you think that the MCs will do a better job of protecting you at that point than a bulkhead that spreads the load.

Quote from Dr John Melvin (GM safety expert) : " The driver can survive incredible g-loads, assuming that the safety cell is not breached. Once it is breached, all bets are off."

[Brian]

I am reading this discussion and relating it to an RF85 that we have - very similar at the front of the chassis to a DB1. Would you say that constructing the additional forward bulkhead in front of the master cylinders, tying that back into the main chassis rails, and then constructing a new nose crushbox forward of that extending the nose bodywork as appropriate, thinking of a 15" or so aluminium box type crush structure hidden inside the bodywork as an example, would be a useful route to take? or making the additional forward bulkhead a mounting point for a composite crush structure/body piece nose like the more modern cars have?

Thanks,

[R. Pare]

Either will work. The current British rules use the additional bulkhead as the mount for the box. The box is an aluminium structure filled with alu honeycomb laid on its side (cells oriented fore/aft).

[Purple Frog]

The front crush box on the new Mygale that ran with the F1600CS a week ago seemed much more adequate than those Al boxes I'm used to seeing. Liberal use of AL honeycomb. Sorry, i didn't take any pictures.

[swiftdrivr]

Here is an idea. Maybe someone with an engineering background can tell me if this would work. Seems pretty low-tech, works from multiple angles, should be cheap to make. Unfortunately, it brings to mind the old saying:, "for every problem there is a solution that is simple, elegant, and wrong."---Jim

[R. Pare]

Close to useless, unfortunately, but better than nothing.

[Art Smith]

Richard-

what are your thoughts on sheet thickness, material thickness, and cell size for the US FFord environment? is a foot of honeycomb in the direction of travel enough/material/better/...............? any ideas on where the knee in the curve is for length in the direction of travel since "more" will always be "better" ?? is aluminum honeycomb the attenuation leader on a per pound basis?

Art
artesmith@earthlink.net

[R. Pare]

The answer is "it depends.......", so it is probably best that I just e-mail you the Cranfield University report - very good numbers in there.

Remember though, when reading the report, that the criterial was a steady 25 g max deceleration - no initial or ending spikes - plus it had to pass push-off tests. If spikes are allowable, the driver can easily handle 80g's (and higher) or a few milliseconds (20-50 or so), and the construction can be different.

[Phil Wellner]

I'm considering fabricating a new front crush structure for my DB-1 based on some of the suggestions in this thread. Part of the project would be moving the master cylinders behind the front bulkhead so that the crush structure could be completely filled with aluminum honeycomb or foam. Does anyone have any suggestions about which grade of aluminum sheet would be best for the box? I'm planning to form the box from 2-3 pieces of Al sheet and rivet it together, so I'd need a grade that can be formed but still has good strength. Would 6061 work?

Thanks,
Phil

[swiftdrivr]

Just curious: I can barely get my feet behind the bulkhead. How are you going to move the master cylinders back there?---Jim

[Phil Wellner]

With the pedals in the farthest back position, and with about 1-2" of bead seat between my lower back and the fuel cell, I still have to stretch to push the clutch pedal all the way down. I'm 5' 9", so I guess my legs are on the shorter side? For what it's worth, I'm planning to use compact master cylinders, which will hopefully save some room. Ideally, the pedals will be about 3-4" futher back than they are now.

[85 SWIFT DB1]

Hello, anyone have a DB1 nose box to sell new or spare?