Is it time for timers on fuel shut off or ignition?

This is a pretty good solution to killing the engine if you have a blowover. It might coud be that with some tweeking it would work to prevent a blowover.
Lets keep working on the problem of preventing one. The problem I see with this type of switch in prventing a blow over is that if positioned at anything less than vertical the g force of accelaration would move the ball against the switch. I would prob. do the same on a mercury switch.

 

I don't think this sort of switch will work.The two a-fuel blowovers that i know of the cars did not go upside down they went up twisted and landed on the tires.Clay's blowover went all the way over,would work in that situation.

 

any time the car goes near 90 degrees on its wheel stand then spirials,that motion itself will also set the switch actuator in motion But I agree This would be a good secondary safety device. Primary should be in prevention.
Rpm activated switch on wheelie wheel to remove timing? Pressure sensor in wheelie bar structure?
All of the top crew chiefs are busy looking for magic in 97 percent to worry about adding more weight and wiring to an already heavy car. The first time one of these devices fail and cause someone to lose a race, woah! look out!
OR! 5 years down the line we look back and find a "zero" blow-over count. Shelly just might leave an even larger\greater mark on this sport than she already has.

Lets get to work.

 

Aircraft Technology

How about this for an idea. Small aircraft use stall warning indicators that are installed on the leading edge of the wing and are to warn the pilot that his angle-of-attack to wind speed ratio is such that his airplane is about to stall and that he better do something or else ...kersplat... Large and commercial aircraft use an instrument called an angle of attack (AOA) vane. Basically the same principle but with much more sofistication. The stall warning indicator is airflow operated, it's a little metal tab that moves and contacts a microswitch when the angle of airflow changes to where it gets under the tab and lifts it up to contact the switch (think of a NASCAR car when it spins and those roof flaps pop up to prevent the car from flipping over Rusty Wallace style). By connecting that microswitch to a relay that would be connected to an electric fuel shutoff that can only be reset manually once it pops (or even to a relay that shuts off power to the MSD) may do the trick. It's operation would work something like this: when the wind direction going over the car changes due to the angle of the car (the beginning of a blowover), the tab will lift due to the airflow change and contact the microswitch, sending a signal to (or taking the signal away from) a relay that would close an electric fuel shut off or remove power to the MSD. The tab would have to be mounted in clean air in the nose of the car to make it work efficiently. I've got several contacts in the aviation industry and will try to find out if the stall switch is available, what the prices are, and who supplies them. They're used in small Cessnas and Pipers in abundance so it should be available.

 

This is a very important topic that needs to be addressed by the entire racing community, including manufacturers.

I can think of several accidents were the driver was killed when they were knocked out upon contact with the wall, then continued downtrack at wide open throttle.

Maybe the answer is a device with several sensors.

Drag cars are design to accelerate hard in one direction.....perhaps a sensor could detect lateral g's, like hard contact with the wall.....and another device could sense if the car is in an unusual attitude like in a blow over.

Wire multiple sensors to one device that kills the fuel system.

Thanks
Mike Little

 

You could shut-down both fuel and ignition at the same time if you wanted to.

This would double your chances of getting it shut down.

 

I think you could put a switch in the wheelie bars so that when after launch any load on it would trip a solenoid shutting off fuel. Or maybe like the top fuelers with the running the chute wires through the wing struts so if the wing breaks off the chute automatically opens, if the wheelie bars break or are bent the fuel gets shut off.

 

reverse distance detector sensor

How about using a Reverse Distance Detector sensor which are already in use on light trucks SUVs and campers? it would have to be configured to work in reverse of its original design though. Their range is from four inches to fifty six I think. Mount the sensor vertically under the nose and integrate it into an electronic/pneumatic switch that would simultaneously shut of the ignition and the fuel. Problems to overcome would be a 12 volt electrical supply. Maybe a pair of nine volt batteries with a voltage regulator? Trying to keep this deal ultra light. The system can be engaged along with the data logger switch. Just a thought.

 

Re: Aircraft Technology

Will, check out this site: www.stallwarning.info They make a pneumatic pressure sensitive system that activates a buzzer when a stall situation occurs. With a little electrical know-how, the buzzer could be replaced with a solenoid. The kit looks like it uses a 9 volt battery. They use it in gliders so it has to be light. It can also be wired in to the computer switch to arm the system so it doesn't inadvertantly go off during the burnout. I think the price is about $375, and a company called Aircraft Spruce sells them (www.aircraftspruce.com). I also think that the use of those backup sensors is a good idea, mounting them underneath the car to reflect the distance between the car and the track.

 

i like the idea of a load sensor on the wheelie bars...

 

Glad to see this conversation going toward the prevention side. One thing to remember as I have stated before is that the wheelie bars would be difficult to use as a pressure or messuring instrament because by sixty feet the height of the wheelie bars from the ground has changed due to the increased diameter of the tire. Prob. to the point that the angle of the car could change and the nose get high enough to blow over when enough speed is attained before wheelie bars contact the ground. So far I think the sensor under the nose is the best idea. It could be used to kill the mags and the height above the ground that it was activated could be adjustable. However if this were a rule the height adjustment would prob. be set by NHRA.
Good posts on this subject so far.

 

still wouldnt the height adjustment be too late, this is my guess as the first 60' of an A fuelers pass is fairly high, and at that point in the run it's alright, but the same 6-12 inches later in the pass is dangerous, or am i off here?

 

http://www.riekerinc.com/E-Inclinometers/SlopeAlert.htm

 

Just another thought on this subject, what about an adjustable proximity switch? You've all seen the ads on T.V. where the vehicle drives into the garage and when the vehicle gets within a certain distance of another object it turns a light on or sounds an alarm. Well, my idea is to use that technology in reverse. The proximity switch is mounted under the body at the front of the car, it reads the distance from the track surface. It could be set up so that if it sees 3 feet or more "air" it triggers a relay to kill the ignition and fuel which would have to be manually reset. Cost for all of the parts including a small sealed 12 volt battery shouldn't exceed $150-$200 plus what ever your time is worth. Total weight gain, maybe 20 lbs. If there is some interest in this, please let me know and I'll put one together, test it and post the results.

Mike Etter/Nerves of Steel AFC

 

Mike, I think that yours is a better idea as g-forces are less likely to trigger it.

Don't Racepaks have a pick up to sense a 12 volt trigger. It could be hooked up to that rather than an ignition cut to monitor for faulty activations while being tested. That way if there were issues, runs would not be aborted.

 

Thats pretty much the same Idea that I posted one page back HERE.. But 20 pounds is A LOT of weight. I don't see the components I suggested weighing that much. maybe 5 pounds tops if that. Jr brought up an interesting point. 12 inches of nose lift at the hit till about 200 feet out isn't much but at 900 feet its disaster. maybe a two stage system that starts at WOT. and the distance is cut in half at 2 seconds after WOT. Or why even have it engage at all until 2 seconds? The driver could easily lift that early in the run.

 

I saw this on another forum. I really don't understand how it works, it says you set a "vertical" g-force threshold that, when crossed, will put out an electrical signal that could be used to retard timing, kill fuel, etc. Has anyone ever seen this or heard of it? It's reasonable inexpensive if it could work on one of these cars.

bryan brown

www.xbasecomputing.com/Dragtraction/index6.html

or go to dragtraction.com and click on wheelie control

 

Hi Woodchip,
My apologies, I didn't mean to steal your idea, I hadn't read through all of the posts I guess, but at least we should agree that there are some pretty good minds all pointed in the same direction. SAFETY FOR ALL! 20lbs is probably a bit high, that was just off the top of my head if you ran a separate battery (dedicated power source), the fuel shutoff solenoid, relay for the mag ground, bracket for the sensor. The actual electronics and wiring would probably be a pound or less.
Keep Smilin!

NervesofSteel

 

why not mount it in the wing area and then you dont even have to reverse it , nose goes up, wing goes down?