Rear Clip Warning Device
Discussion
This is a subject that was picked up on my "painting" post.
Am moving it over here because it might get more input.
In flying, there's a saying that refers to flying complex aircraft, and that is "if you haven't already done it, you will". This saying is refering to landing with your wheels up. I have to say in over 6000 hours of flying and over 6000 landings, I've remembered to flick the switch down every time, but I'll be damned if with under 6000 miles on the CanAm, if I didn't remember to check the rear clip. The result was a loud noise, an awful scraping sound, and instant lack of use of the rear view mirrors, followed by a loud "Awe shit". It's amazing how much resin and glass can be scraped away in such a short time. Repair and painting took 4 days.
Steve and Simon have mentioned about a safety latch and a warning device.
Was looking at the car today, and until a safety latch comes along I think I see a method for an easy to install warning light.
What I've noticed with the CanAm when one of the side latches has not caught, is that I'll get a rattle when passing over some uneveness in the road. So we stop, unbuckle, get out of the car, and with two hands and palms down, give the panel a hefty slap until the latch engages. We've even had both latches loose, but the center safety latch, as flimsy as it is, holds it until the rattles get my attention. This has worked to at least 55 mph. I didn't test it further.
Knowing this, and since both sides of this center safety catch is attached to fiberglass, it would be a simple matter to feed 12 volts (with an in-line fuse) to one side of the latch, and run a wire from the other side to a warning light on the panel, then to ground. This would keep a light on all the time the latches were together. If you'd prefer to have the light on only when the latches are open, you'd need to use a relay that will close the circuit when there is no voltage going to the holding coil.
Getting a false reading by having the 2 halves of the latch just touching each other, without being latched, can be avoided by insulating areas of the latch so electrical contact is only made when the latch is closed properly.
Your input is welcome
Jack
>>> Edited by USCANAM on Monday 10th November 23:04
Am moving it over here because it might get more input.
In flying, there's a saying that refers to flying complex aircraft, and that is "if you haven't already done it, you will". This saying is refering to landing with your wheels up. I have to say in over 6000 hours of flying and over 6000 landings, I've remembered to flick the switch down every time, but I'll be damned if with under 6000 miles on the CanAm, if I didn't remember to check the rear clip. The result was a loud noise, an awful scraping sound, and instant lack of use of the rear view mirrors, followed by a loud "Awe shit". It's amazing how much resin and glass can be scraped away in such a short time. Repair and painting took 4 days.
Steve and Simon have mentioned about a safety latch and a warning device.
Was looking at the car today, and until a safety latch comes along I think I see a method for an easy to install warning light.
What I've noticed with the CanAm when one of the side latches has not caught, is that I'll get a rattle when passing over some uneveness in the road. So we stop, unbuckle, get out of the car, and with two hands and palms down, give the panel a hefty slap until the latch engages. We've even had both latches loose, but the center safety latch, as flimsy as it is, holds it until the rattles get my attention. This has worked to at least 55 mph. I didn't test it further.
Knowing this, and since both sides of this center safety catch is attached to fiberglass, it would be a simple matter to feed 12 volts (with an in-line fuse) to one side of the latch, and run a wire from the other side to a warning light on the panel, then to ground. This would keep a light on all the time the latches were together. If you'd prefer to have the light on only when the latches are open, you'd need to use a relay that will close the circuit when there is no voltage going to the holding coil.
Getting a false reading by having the 2 halves of the latch just touching each other, without being latched, can be avoided by insulating areas of the latch so electrical contact is only made when the latch is closed properly.
Your input is welcome
Jack
>>> Edited by USCANAM on Monday 10th November 23:04
It sounds like a couple of pin switches are what you need. You could easily use one of those headlight warning buzzers to sound off if the clip isn't shut properly and the ignition is on. Relying on hearing a rattle seems a bit dodgy to me.
Or you could just be paranoid and check that it's clipped down as part of your pre flight check routine
James
Or you could just be paranoid and check that it's clipped down as part of your pre flight check routine
James
I would have thought that a pin switch would just tell you that the horse had bolted. By the time it operates the back bodywork is on its way to oblivion....?
Something like the contact switch Jack describes with the over centre latch sounds good though it might be tough to make it insulate reliably.
Another thought (which I think someone has mentioned before) is a microswitch on both rear catch mechanisms. They seem to have a very positive action by design and have quite a throw from on to off so it should be possible to get this hooked up to a microswitch.
Wiring any switches to the ignition system seems a little foolish. You can bet that it'll fail at the most inopportune moment - say mid-overtake.
The starter might be a better bet along with a lamp/buzzer.
Something like the contact switch Jack describes with the over centre latch sounds good though it might be tough to make it insulate reliably.
Another thought (which I think someone has mentioned before) is a microswitch on both rear catch mechanisms. They seem to have a very positive action by design and have quite a throw from on to off so it should be possible to get this hooked up to a microswitch.
Wiring any switches to the ignition system seems a little foolish. You can bet that it'll fail at the most inopportune moment - say mid-overtake.
The starter might be a better bet along with a lamp/buzzer.davefiddes said:
Wiring any switches to the ignition system seems a little foolish. You can bet that it'll fail at the most inopportune moment - say mid-overtake.
I don't know about how you wire things up, but when I connect a wire to something, it usually stays connected. If you can't connect a wire reliably to the ignition circuit, I can't see how you'll manage any better on any other one. Then again, if you can't connect a wire up properly, maybe you shouldn't be building an Ultima
If your ignition switch does fail "mid overtake", I think a buzzer going off is going to be the least of your worries. I'd be more concerned with the sudden absence of a running engine
James
james said:
If your ignition switch does fail "mid overtake", I think a buzzer going off is going to be the least of your worries. I'd be more concerned with the sudden absence of a running engine
I perhaps could have phrased things better. What you describe is what I intended to say. A buzzer/lamp you can deal with but a sudden loss of ignition is hard to cope with.
Like you when I attach a wire to something it stays attached! However as we are talking about electro-mechanical switches here, exposed to moisture, heat, dust and vibration from the engine bay. You can do a lot to help by picking the correct parts but sooner or later they will fail and long before the ignition switch (in the safety of the cockpit) and wiring gives up the ghost. Murphy's Law applies here.
Agreed that a 'cut' ignition is not the best thing to have in a fast moving situation, but I would have possibly been able to avert the whole rear clip coming off if I had an early warning, no matter how short it was. I have played the whole incident over and over in my mind (well it's inscribed now!) and I am still convinced that if I was given some warning I would have been able to stamp on the scrubbers and prevent the wind from getting under one side of the rear clip, which is what caused the other one to fail.
One clip had come undone, and the other clip was ripped through the fibreglass with bolts and washers as well. My original thoughts were that the retainer lug should have been fitted with a steel backing plate to spread the weight through the fibreglass, but this is rubbish because the force would have just pulled the whole plate throuh the fibreglass.
This brings forth two alternative schools of thought:
1) A secondary catch mechanism is needed (like Steve D was discussing on the paint thread). This would allow enough movement if the first position was released for a switch to be activated before the hood was released, and I think is the way forward.
2) Is to use a different and independant holding method, and for this I have found these:
http://rswww.com/cgi-bin/bv/browse/Module.jsp?BV_SessionID=@@@@1790986380.1068578910@@@@&BV_EngineID=ccccadcjlflkhegcfngcfkmdgkldfhg.0&cacheID=ukie&3246031739=3246031739&stockNo=825900
You will have to paste the whole damned lot in your browser to view it unfortunately. These electro-magnets are available in 12V and provide massive holding power. The benefit is that they are only 'on' when the engine is running, which is when you need it. I can get these cheaper from a local Fire Alarm Company - two for the price of one.
It may well be extreme but until a secondary locking mechanism is available, I am going to give them a go.
One clip had come undone, and the other clip was ripped through the fibreglass with bolts and washers as well. My original thoughts were that the retainer lug should have been fitted with a steel backing plate to spread the weight through the fibreglass, but this is rubbish because the force would have just pulled the whole plate throuh the fibreglass.
This brings forth two alternative schools of thought:
1) A secondary catch mechanism is needed (like Steve D was discussing on the paint thread). This would allow enough movement if the first position was released for a switch to be activated before the hood was released, and I think is the way forward.
2) Is to use a different and independant holding method, and for this I have found these:
http://rswww.com/cgi-bin/bv/browse/Module.jsp?BV_SessionID=@@@@1790986380.1068578910@@@@&BV_EngineID=ccccadcjlflkhegcfngcfkmdgkldfhg.0&cacheID=ukie&3246031739=3246031739&stockNo=825900
You will have to paste the whole damned lot in your browser to view it unfortunately. These electro-magnets are available in 12V and provide massive holding power. The benefit is that they are only 'on' when the engine is running, which is when you need it. I can get these cheaper from a local Fire Alarm Company - two for the price of one.
It may well be extreme but until a secondary locking mechanism is available, I am going to give them a go.
Have read Ted's explanation over several times as to why you'd want the rear clip to damage itself by going vertical instead of stopping before it gouged itself to pieces on the asphalt.
IMHO, I'm submitting the following observations.
I found the clip opened at around 55mph on the CanAm. It might not of opened at all if the wing wasn't mounted. The rattling of the clip might have gotten my attention.
I suspect this might happen at a lower speed on the GTR because of the high air scoop.
I'm sorry Ted, but I cannot agree that the rear end of the car will become airborne if the clip is not allowed to be vertical unless the vehicle is at .2 mach. Unless there is a massive failure of the latches, the clip will open long before a high speed is reached.
What I, (please note "I") intend to investigate, is the installation of;
1. a secondary locking device,
2. a warning of an unlatched condition,
3. tethers of 1/8' stainless steel cable that will be slightly longer than the throw of the gas struts and utilize these springs which will help absorb some of the sudden opening shock.
www.aircraftspruce.com/catalog/lgpages/comp_springs.php
My clip is already re-enforced to accept the tether on each side. Cables can be assembled very neatly at an airport that has swaging equipment and fittings.
Once again, this is what I plan on doing. I'm not recommending this approach for anyone else.
Not trusting the latches the first time I had the car on the track, I even duct-taped all the rear seams just in case the track vibrations caused the latches to open. Everything held fine, and that was the end of the tape once I was sure all latches were working OK.
I really can't see any reason for massive damage to the rear clip in case of an accidental opening.
To date, I've read about 3 openings on this forum.
If anyone can provide proof of an Ultima becoming airborne when the rear clip opened, I'd be interested in seeing it.
Jack
IMHO, I'm submitting the following observations.
I found the clip opened at around 55mph on the CanAm. It might not of opened at all if the wing wasn't mounted. The rattling of the clip might have gotten my attention.
I suspect this might happen at a lower speed on the GTR because of the high air scoop.
I'm sorry Ted, but I cannot agree that the rear end of the car will become airborne if the clip is not allowed to be vertical unless the vehicle is at .2 mach. Unless there is a massive failure of the latches, the clip will open long before a high speed is reached.
What I, (please note "I") intend to investigate, is the installation of;
1. a secondary locking device,
2. a warning of an unlatched condition,
3. tethers of 1/8' stainless steel cable that will be slightly longer than the throw of the gas struts and utilize these springs which will help absorb some of the sudden opening shock.
www.aircraftspruce.com/catalog/lgpages/comp_springs.php
My clip is already re-enforced to accept the tether on each side. Cables can be assembled very neatly at an airport that has swaging equipment and fittings.
Once again, this is what I plan on doing. I'm not recommending this approach for anyone else.
Not trusting the latches the first time I had the car on the track, I even duct-taped all the rear seams just in case the track vibrations caused the latches to open. Everything held fine, and that was the end of the tape once I was sure all latches were working OK.
I really can't see any reason for massive damage to the rear clip in case of an accidental opening.
To date, I've read about 3 openings on this forum.
If anyone can provide proof of an Ultima becoming airborne when the rear clip opened, I'd be interested in seeing it.
Jack
USCANAM said:
Have read Ted's explanation over several times as to why you'd want the rear clip to damage itself by going vertical instead of stopping before it gouged itself to pieces on the asphalt.
IMHO, I'm submitting the following observations.
I found the clip opened at around 55mph on the CanAm. It might not of opened at all if the wing wasn't mounted. The rattling of the clip might have gotten my attention.
I suspect this might happen at a lower speed on the GTR because of the high air scoop.
I'm sorry Ted, but I cannot agree that the rear end of the car will become airborne if the clip is not allowed to be vertical unless the vehicle is at .2 mach. Unless there is a massive failure of the latches, the clip will open long before a high speed is reached.
What I, (please note "I") intend to investigate, is the installation of;
1. a secondary locking device,
2. a warning of an unlatched condition,
3. tethers of 1/8' stainless steel cable that will be slightly longer than the throw of the gas struts and utilize these springs which will help absorb some of the sudden opening shock.
www.aircraftspruce.com/catalog/lgpages/comp_springs.php
My clip is already re-enforced to accept the tether on each side. Cables can be assembled very neatly at an airport that has swaging equipment and fittings.
Once again, this is what I plan on doing. I'm not recommending this approach for anyone else.
Not trusting the latches the first time I had the car on the track, I even duct-taped all the rear seams just in case the track vibrations caused the latches to open. Everything held fine, and that was the end of the tape once I was sure all latches were working OK.
I really can't see any reason for massive damage to the rear clip in case of an accidental opening.
To date, I've read about 3 openings on this forum.
If anyone can provide proof of an Ultima becoming airborne when the rear clip opened, I'd be interested in seeing it.
Jack
YHM
Jack and Other Can-Am and GTR Owners,
I'm a little confused. I own the older sports that uses PIP pins to secure the rear panel so excuse my ignorance here. Maybe I'm misunderstanding what's happening, but wouldn't you think the design of the locking mechanism would be such that the panel locks automatically upon closing? Why should you have to push down on the panel to make it latch? The thing should latch upon closing in my opinion. Anyone have any photos to help me understand?
Thanks!
-Mack
I'm a little confused. I own the older sports that uses PIP pins to secure the rear panel so excuse my ignorance here. Maybe I'm misunderstanding what's happening, but wouldn't you think the design of the locking mechanism would be such that the panel locks automatically upon closing? Why should you have to push down on the panel to make it latch? The thing should latch upon closing in my opinion. Anyone have any photos to help me understand?
Thanks!
-Mack
Well, I asked for some proof of the after-effects of a runaway rear clip causing an Ultima to lift it's rear, and I got it by direct email. I thank the sender for the details which for obvious reasons I cannot, nor will disclose.
I'm thankful the sender survived to be able to relate the details.
However, the cures, or mods I intend to apply, such as the tether, will only perhaps work at low speeds. I would not expect them to work much above 55 mph.
Had I had the tethers on before, and it worked, it would have saved me 4 days of messy repair work.
Had the clip latches come loose when I was on the drag strip and approaching 140 mph, there's no doubt in my mind that the whole clip would have departed the car with the expected geometric reactions to the car.
I'm thankful the sender survived to be able to relate the details.
However, the cures, or mods I intend to apply, such as the tether, will only perhaps work at low speeds. I would not expect them to work much above 55 mph.
Had I had the tethers on before, and it worked, it would have saved me 4 days of messy repair work.
Had the clip latches come loose when I was on the drag strip and approaching 140 mph, there's no doubt in my mind that the whole clip would have departed the car with the expected geometric reactions to the car.
I'm with Mac on this. I also have a Mk4 (for the time being anyway) which has pip pins to hold the rear clip shut. Maybe Ultima should consider going back to this somewhat less elegant looking, but apparently more reliable fastening.
Saying that, I replaced the pip pins on the front of my car with spring clips, as I didn't trust the pip pins to hold in case of a racing incident, and I didn't want to risk a possible lost bodywork, so maybe I'm a bit obsessive about keeping the bodywork where it is supposed to be
James
) which has pip pins to hold the rear clip shut. Maybe Ultima should consider going back to this somewhat less elegant looking, but apparently more reliable fastening. Saying that, I replaced the pip pins on the front of my car with spring clips, as I didn't trust the pip pins to hold in case of a racing incident, and I didn't want to risk a possible lost bodywork, so maybe I'm a bit obsessive about keeping the bodywork where it is supposed to be
James
I thought that the reason that pip pins or some other external catch wasn't used any more was because they would fail the external projections part of the SVA...as well as being less aesthetically pleasing.
This problem can't be unique to Ultima. I wonder what other mid engine cars do (if anything ) to avoid this problem?
This problem can't be unique to Ultima. I wonder what other mid engine cars do (if anything ) to avoid this problem?
Some of the GM cars use (or used) a type of latch that I believe could be adapted to the Ultima. They used a pin type latch with a safety catch that had to be actuated at the bonnet. Corvette used this on thier hoods in tandem. Although they were used on a forward opening "clamshell" type hood, I'm sure two regular pin type latches could be adapted to the Ultima with the safety catch still operational.
The problem with the bonnet pins is you still have to remember to fit them. As memory fade is the only issue with the existing latches we haven't moved forward.
If I understood Simons post correctly only one of the side latches was unlatched and the other ripped out when the wind got underneath.
If this is so then my thought of a safety catch is unlikely to be strong enough anyway so I have binned the idea.
Microswitches on both latches or fitting pin switches in the shut line now has my vote.
Steve
If I understood Simons post correctly only one of the side latches was unlatched and the other ripped out when the wind got underneath.
If this is so then my thought of a safety catch is unlikely to be strong enough anyway so I have binned the idea.
Microswitches on both latches or fitting pin switches in the shut line now has my vote.
Steve
US-GTR said:
Sorry if I wasn't too clear. The GM latches had a pin (about 25mm +/- in diameter) that protruded into an automatic latch. All that was needed was to close the bonnet. These latches were OEM fittings.
Agreed these ones may be automatic but I think the others being refered to were the type you needed to lock using an 'R' pin on a lanyard. Hense the observation that this could be as easily forgotten as the 'final palm push' to lock the factory latches.
Steve
You could always go for the solution that Mercedes have used on the tailgate of my car. You just put the lid down gently. As it gets close to shutting, an electric latch engages and closes it the last inch or so. No need to push down or slam the lid at all. It's pretty near impossible to prevent the latches from engaging and closing too.
Of course, this solution might be a bit of a sledgehammer to crack a nut
Of course, this solution might be a bit of a sledgehammer to crack a nut
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