parachute quickness/ finishline activation/engine braking

since the last few pdra crashes I have some questions
what is the quickest and lightest activating parachute
1-air deployed
2-spring deployed
3-pilot pulling everything out (lightest and what I have)

I see a lot of crashes at the finish line on automatic cars, maybe from engine braking , slick track,
being out groove, liquid or something on tires
when you have a car out of the groove and a hand full of steering wheel its hard to get the chut out
at the same time you lift (engine braking from automatic)
not many will save it when things happen this fast
has any body thought about say after 3 second or so (depending 1/8 or 1/4)
putting a wot long throw switch under throttle and activating the parachute when lifting to say 1/8 throttle
(or a idle switch with 3 sec delay )

or these cars need a large sprag on driveline so it can free wheel when lifting
it has to lock so we can backup

I bought the tuterow air pod and solenoid so it dumps air when power is shut off

I don't think any of this is fast enough and needs to be automaticly activated
(dump air and parachute when lifting off throttle

any ideas on how to do this
thanks

 

how about activating the chutes and cutting the engine with a YAW sensor? Car wiggles to a certain degree, and the computer takes care of it. Like a sideways G sensor?

 

Air activated release with a button on the steering wheel.

 

Voice activated. When the driver says "Oh Sh$%..." the auto sequences kick in .

 

Actually this is a very good topic for discussion, and one that needs to be openly addressed for safety at some point.

Let's collectively look at the recent Ronnie Davis crash as an example, and figure out what could have been done different to either prevent or mitigate his incident.

Automated systems deployed, different design personal safety systems, different head protection, different suspension, stable aero, controls, devices, etc......

 

If you watched that car every round something was wrong with it. It never got off the line. Like possibly something was broke or breaking. I'm really suprised that Lahee or Davis hasn't came up with a lateral g sensor that would deploy chutes if it exceeds a certain g.

 

Might be, but an "Oh Shit" autonomous deploy button might have helped him if he had it at his thumb or his fist for immediate grab.

Or how about a supervised external "Oh Shit" remote button held by someone watching like a track official or spotter or crew member? Chutes out earlier would have snagged him around maybe?

To me watching the video over and over, it looks just like any other PS or PM or TS loss of control at the top end with current thinking aero/chassis thinking. Steer, trip, massive switch oversteer, and then flung off to a bad state with air under the body.

Not the driver's fault for trying to correct, but he's doomed from the outset with what he has to work with in a timely fashion.

How do we make these vehicles inherently directionally stable and safe? How do we readily automate the safety systems? How do we make these vehicles autonomously safe if the driver does not (or cannot) intervene?

I don't have the answers, just a bunch of wondering questions.....

 

Roof flaps like NASCAR has would probably have kept the car from becoming airborne and the wall would have kept it on the track IMHO

 

I watched that run at least a hundred times. Thank you very much MotorMedia for not taking it down. I'm sure Ronnie would like the racing community to figure out what happened so another racer doesn't get lost.

I just went through a crash in the fall and it was due to no chutes and the tires got locked up by necessity. From what I saw, Ronnie's chutes never deployed. I'm wondering if the brakes were hit too hard and the tires couldn't slow the car but instead got it airborne by breaking the friction of the tire to the surface.

My thought is that we may need a slow speed braking pressure and a high speed braking pressure. I say this because at slower speeds we at times need to bury the pedal to stop, especially with carbon when it's cold. At high speeds with a chute, no issue as you are used to a light pedal and the chutes pull the back of the car down helping it to brake and the natural help of the chute does not create a panic situation. When a run has no chutes and there is no downforce and the turnoff is coming up quick the tendency is to give it more foot. When that happens, the fronts lock and the rears either bounce or leave the track altogether.

I'm like Duanne as I'm not sure what transmissions have sprags to provide or not provide engine braking, Engine braking at this speed in my opinion would just exacerbate the issue. I think you need to rely on the chutes and brakes but what do you do if the chutes fail? That is why I think a lower pressure brake system is needed at speed and then at a lower speed the higher rate kick in.

I don't have the answers but just throwing it out there as I'm sure input from the smart minds will produce an answer.

Tom Dwyer

 

How about mounting a g meter sideways and then program the ecu the parameters that works with your particular racecar. Have let's say , 1 - 2 G's of side force activate the chutes and cut power to engine.

 

Speaking of parachutes, how many T/ADs and BB/FCs are running Stroud's? Are any T/F cars using them?

Thanks
EDB

 

I think the first time the G-meter shuts the car off from a little tire shake it will be removed or bypassed by the driver/ owner. I don't think there would be enough lateral G unless the car hit the wall to be useable.

Let's remember these are race cars and they are going to do crazy unexpected things. I believe the focus should be on keeping the driver safe during these situations. The Hans, lateral pads and pour in seat are all excellent additions to the safety of the driver. Seven way harnesses also help to keep the position of the driver where it should be. If these items were mandatory (not sure what the rules require for these cars) it could save a lot of pain and possible lives.

The last thing is the driver should always throw the chute at the end of the pass, even if eight mile racing on a quarter mile track. It helps to stabilize the car during the deceleration event and lets face it they are not that hard to re-pack.

Just a side note, every clutch car will have engine braking until the driver shoves the pedal in (takes time to get engine down far enough to overcome counter weight) or dumps the air from the trans. Not sure how many door cars run a clutch but worth noting.

 

With converters of the like that we are talking about, not locked, is there really much engine braking during throttle lift? I don't know, only asking.......

 

I think you could taylor make a system for each car. The problem with keeping the driver safe is our bodies aren't designed to be upside down and taking that kind of impact. The key is to prevent the roll- over & crash to begin with.

 

This thread really got me thinking on the engine braking comments. I always thought people wanted to limit engine braking by putting the car in neutral at the stripe to save engine parts. Since I never did, I did not consider the effects of the engine braking locking up the rear tires as I never ran into that issue or any engine related issues. What I have run into, as I stated above, was using extra brake pressure due to a no chute situation and the car getting into a hopping situation. In thinking about it, if the rear tires bounce and leave the surface and then come down and have to fight the engine due to being in gear, that would intensify the bouncing. Anyone run into this? It sounds like adding the dump valve may help alleviate or at least minimize this situation? Can anyone confirm this as a reason to use the dump valve for the Lenco air pods? Not sure if dumping pressure on the convertor would help but wonder if anyone is doing that at the finish and what results that produced?

 

As far as shifting into neutral, obviously it can't be done on a Lencodrive, relying on the convertor for engine braking. When I switched to turbos, I added 2 calipers to the rear of my dragster. My son says the brakes are really great now.
I could see where dumping convertor pressure would kind of be like pushing in the clutch ? Like Blownalky, I'd like to know also!

 

I have an emergency button in the center of the steering wheel that is wired to a relay that kills the 8973 ignition box AND energizes an air solenoid that deploys the chutes. As mentioned in other comments, I might not want to let go of the steering wheel to deploy a chute and then hunt for the kill switch in case of upset, loss of control or a stuck open throttle. Just my 2 cents.

 

I forgot to mention that while the car has a standard foot brake, I also installed a hand brake with a second set of brake calipers on the rear with a second master cylinder activated by a hand lever that is a "pull" handle so that while the chutes are deploying and if I use the hand brake,and if the car starts to hop, the natural action of my arm being moved forward by the hop reduces the amount of brake I am applying this reducing the hop instead of magnifying it like a foot brake would. Another 2 cents worth, so 4 cents total.

 

If it saves you from crashing, it's priceless! I like the set-up.