Front Impact Attenuation

[Veefan]

Has anyone built a front impact attenuation structure for a Vee for additional safety? I know a few guys have sprayed insulation foam in the nose... any other ideas or pictures?

9.1.1.C.3.A.10

10. No structure, item, or component (including the battery) other than bodywork, can protrude further forward than ten (10)
inches from the front of the lower axle beam tube. Any item protruding further than eight (8) inches must include a vertical
safety plate. This plate must be constructed of no less than .060” 6061-T-6 aluminum or no less than 16 gauge steel. The
plate shall have a minimum frontal surface area of 42 square inches, and shall have a height of not less than four (4) inches
and a width of not less than six (6) inches. The plate may have no more than ½ inch curvature or deflection from the
vertical plane, and shall be attached to the chassis (frame) at all four corners. The lower braces shall not exceed a 15-degree
upward angle when measured from the horizontal plane of the lower frame tubes. If a vented lead acid battery is mounted in front of the axle beam, it shall be encased in a marine-type container. It is recommended that the front area of the nose be filled with foam to aid in impact absorption.

[Bill_Bonow]

Here is one mounted on the front of an FST (sorry). We've taken them off as they are no longer required by SCCA (if you use a VW H-beam front suspension)

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[hardingfv32-1]

You would be much better off with a crash structure in the rear. The chance of a back or neck injury are much greater from a rear impact. I can list many rear impact injuries, but have almost no recall of a front impact injury.

Brian

[jpetillo]

Brian, this is an excellent point. Not that a front attenuator isn't a good idea, but one in the rear would be good since the driver has no where to go in a rear impact - you're almost solid against the seat and helmet pad - just an inch or so. It's not clear how the head/body relationship changes in a rear crash.

[Veefan]

I found this F1 testing on the web, a cool read for the techies.

http://f1-dictionary.110mb.com/nose_cone.html
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"After data from the onboard accident data recorder had been analysed it was found that he had been subjected to a peak G-force of 75 G. It was initially reported that Kubica could have a broken leg. However, Mario Theissen later confirmed that he was not seriously injured"

[brian]

Being completely intact during impact would be preferred and having a well fitting seat is critical in this situation. Another critical element is a seventh strap to prevent anti submarining in case of a rear impact. If you are in a reclined position and hit hard going backwards, you will be driven up the incline and out of the seat unless there is sometime to hold the lap belt down. The shoulder belts will rotate over the driver's shoulders has the driver moves up and out, pulling the lap belt with you. Spent eight weeks in a neck cast as a result of incident just like discussed. SCCA recommends a 7th belt, I won't run without one.

With the overall length specified in our class finding room for an extension will prove a challenge. Using thin wall tubing on the rear structure will absorb a lot of energy but cost some repair time. Some cars have bolt on sub frames to provide this feature.

[jmattox]

I had a chance meeting with 2 SRF'S one February at Sebring out of turn17. My throttle cable broke and I had 1000 rpm and third gear. Made a "rookie" mistake in NOT turning left on entrance to 17, if I had the Zink would still be intact, but, life goes on. The first one hit me as we exited 17 and "just" took my right rear off. The second one sorta ignored the flags, if there were any. He came around nose to tail behind the one that the video shows an SRF going around me on the left. Then all hell broke loose. The second SRF hit me almost square on in the rear. ALL my safety gear did what it was supposed to do. My butt was bruised for about 3 weeks after and the Zink was OK, from the roll bar forward. No seat, on fuel cell, Al sheet separating me from FC, 5 point harness, oh yeah shoulders were bruised also, head rest sorta got rearranged. I actually assisted in the clean up while pack went though 12 hr pits. Went to E-room after drive back to Tampa and they said A-OK. All this to say, front impact attenuation may be over rated. I am glad I lost a transmission, cause that guy hit me awfully hard. Oh yeah we used to engine case in the Vista, until we spun a rod bearing. Like I said, that is another story.

John
FV42

[brian]

I know how it feels to be pummelled by a SRF. Make your self a seat and go to at least a 6 point system. I recommend a brace behind all headrests. Solo aluminum may not withstand the 200# strength requirement.

[Mad Dog Racing]

Rather than a crush structure for your car, I thought the purpose of the front attenuation was to prevent 'spearing' someone in another car with something extending from the front of your car. Maybe I'm incorrect - again. The way I read it, the old nose filler/push bar that supported a battery was no longer legal unless it was 9 square inches or something. (That never was a good idea anyway, having the battery in front of the beam, even after the change to gel cells.) But the old square noses were great for pushing with a bar in there.

[brian]

You're right Mad Dog. The GCR quote above was a anti-penetration provision not attenuation.

[Veefan]

The first sction in th GCR is 9.4.5.G

G. Front Impact Attenuation
1. All formula cars registered or homologated with SCCA as of
1/1/1986 must have a front impact attenuation device meeting
at least one of the following criteria:
A. An FIA-approved front impact attenuation structure.
B. A metallic structure, securely attached to the front bulkGCR
- 96
9. Cars and Equipment
head, with a minimum cross section of 200 sq cm (31 sq
in.), 40 cm (15.75 in.) forward of the clutch and brake
pedals (not depressed), constructed of a minimum of 18
gauge 6061-T4 or equivalent aluminum.
C. A non-metallic composite structure, securely attached to
the front bulkhead or incorporated into the nose piece,
with a minimum cross section of 200 sq cm (31 sq. in.),
40 cm (15.75 in.) forward of the clutch and brake pedals
(not depressed), constructed of a minimum of 6 mm stabilized
(e.g., honeycomb) material with inner and outer reinforcements
of a minimum of 2 5-ounce laminate material
(fiberglass, carbon, Kevlar, and so on).
2. Formula Vee and other formula cars using the VW sedan
H-beam front suspension must satisfy the requirements of
section 9.1.1.C.3.A.10 or use any of the structures listed in
9.4.5.G.1.

[RacerGeek]

So the next question is, what does 9.1.1.C.3.A.10 say...

10. No structure, item, or component (including the battery) other
than bodywork, can protrude further forward than ten (10)
inches from the front of the lower axle beam tube. Any item
protruding further than eight (8) inches must include a vertical
safety plate. This plate must be constructed of no less than
.060” 6061-T-6 aluminum or no less than 16 gauge steel. The
plate shall have a minimum frontal surface area of 42 square
inches, and shall have a height of not less than four (4) inches
and a width of not less than six (6) inches. The plate may
have no more than ½ inch curvature or deflection from the
vertical plane, and shall be attached to the chassis (frame) at
all four corners. The lower braces shall not exceed a 15-degree
upward angle when measured from the horizontal plane of the
lower frame tubes.
If a vented lead acid battery is mounted in front of the axle
beam, it shall be encased in a marine-type container.
It is recommended that the front area of the nose be filled with
foam to aid in impact absorption.


As I read it, if you have anything greater than 8" inches but less than 10" inches ahead of the lower axle beam tube, you need the plate as described in this section. If you have anything more than 10" inches ahead of the lower axle beam tube, you need a crash attenuator from the other section of the GCR. SCCA confirmed that when I emailed them about homologating the Womer 2 years ago.

[hardingfv32-1]

Very sharp observation! I learned something today.

Brian

[cendiv37]

I think the "no structure, item or component other than bodywork" wording from the FV rules would exclude even an attenuation device that extends more than 10" ahead of the lower beam tube, unless the attenuation device WAS the bodywork. I'm just stating my opinion here and SCCA might think otherwise. I don't know whether you can (always -> in all FV's with all drivers) meet the attenuation rules 15.75" ahead of the clutch and brake pedal requirement and stay within the 10" max ahead of the beam, but as I interpret it, this is what you would have to do.

The FV rule was written to protect drivers in other FV's, NOT the driver of the car that must meet the rule. The attenuation requirement is newer and when first introduced caused a bunch of confusion with FV. That is what brought about the specific exclusion of cars with H-beam front suspension.

[remmers]

never quite understood though, we have that rule for puncture safety... but in a lot of cases we run with fords which have relatively sharp attenuators that could possibly puncture a vee.