GT40 fails parachute brake tests in Scotland - Page 2

Hershal Byrd · 10-30-03, 04:14 PM

I have been here waiting to be sure there were no photos that would appear on my senior moment. Yes, it happened to me at Run and Gun. I was talking to a gentleman about the RF GT as I was lowering the rear clip. As I did this the announcer made a last call to the track and I got in a hurry and excused myself from the gentleman then quickly slid my helmet on and off I went without clasping the rear clip. I went around that track twice and nothing happened because I was being held up by a guy in front who was super slow and you could only pass on the straight. On the third lap I got my chance and went for it. As I was halfway throught the straight, approaching 110 MPH, I get this tremendous tug on my safety belts and I hear this awfull grinding noise. The GT had slowed to abot 70 MPH and I look out the rearview mirror and see this reflective shield material and thats when it registered. Talk about embarassing! Man, in less than 3 seconds I was 3/10ths from loading my shorts, confusion, and embarassment. I will garantee that if it happens to you once you won't let it happen again.I can't sit in the darn car now without thinking about it.
I was lucky too as the damage was minor. It only scraped up the rear spoiler and bent the clip hinges enough that we removed and restraightened them.
I really like MikeD's and Bill's way the best. I for sure will have a similar system on mine soon.

Hersh [img]/ubbthreads/images/graemlins/smile.gif[/img]

Bill Bayard · 10-30-03, 04:52 PM

The safety pin passes through a billet ferrule affixed to the door jamb inside the cockpit. On the engine bay side of the spider, and on the rear clip, it passes through Dzus plates, which are drilled out to the size of the pin.

dave harris · 10-30-03, 08:25 PM

I have the DRB system as well and just to make the system overly safe (I'm not too fond of the actual rear clip latches - may redesign) I've added another one of those pins to the passenger side as well. With both pins in, as Bill said, you would have to rip out a couple of FEET of fiberglass!

Howard Jones · 10-31-03, 12:32 AM

Here's how I did mine.

Malcolm · 10-31-03, 04:48 AM

Hersh, your experience is just what is most likley to happen to owners out there. The bonnet pin approach allows a quick visual check which is why it appeals to me. However my main issue on bits flying open at speed only relates to when I go backwards at 65 mph or greater!

I am of course talking about when the car is on a trailer with the engine end loaded on first. So if I get distracted when loading the car on to the trailer I may forget to check the doors are fully shut. At speed they are likley to pop open with resulting stress being put on the door check straps. And if a check strap snaps then its fibre glass time. I will learn one day!

Malcolm

Frank Catt · 10-31-03, 07:57 AM

Bill, I like the idea that you really cannot get into the car unless the rear clip pins are home and locked - good idea, Frank

Bill Bayard · 10-31-03, 09:33 AM

Frank,

All the credit for the pin, etc., goes to Peter Ransom of GT40 Australia. I am just the lucky benefactor of his engineering.
The pin on the seat was my idea. As is evidenced by previous posts in this thread, a little bit of
a distraction can cause a small disaster! Keeping in the habit of putting the pin on the seat each time it's removed, could save the day. The pin under your butt is a good reminder, if you should be distracted. [img]/ubbthreads/images/graemlins/shocked.gif[/img]
Bill

TomG · 11-05-03, 03:06 AM

To close out this particular thread, here is a picture of where the rear deck landed.

I'm pretty sure what happened to me was as follows:

I got the car airborne over a bump, and the landing was quite severe (should have stopped to check, but did not).
I had been having trouble getting one of the slam catches adjusted to my liking - ie nice and solid closing action. Also, I had not packed the shutline around the "toblerone" with rubber - so, with the deck closed, there was still 3mm or so of downward movement on the deck, with all latches closed (ie until the top of the toblerone made contact with the top of the aperture it fits into).

When I went over the bump, I think the deck slammed down then back up, the impact of this shock load opened the poorly adjusted slam catch, and possibly damaged the
overlocking catch on that side (as Frank says - secured by 2 self tappers into the chassis rails).

Later, at speed (4000revs in top and accelerating), I think the twisting motion of the deck (now loose at one side) was enough to open up the other side & away she went!

The car now has 2 bonnet pins, in addition to well adjusted slam catches, with heavier release cables, and Frank modified the fibreglass on the rear deck, local to the slam catch mounting, to ensure the release cables were not fouled as the deck closes - which we thought mine were being. I'd advise anyone who has just the standard slam catches without additional bonnet pins etc to check this aspect.

It has been good to share these ideas & different solutions we all have - plenty for me to think about and take account of when I build my next 40 !!

Thanks to all of you for sharing your thoughts!

Tom Gollan.