Landracing Forum
Tech Information => Technical Discussion => Topic started by: Jonny Hotnuts on January 12, 2011, 12:06:27 AM
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Considering the concept of using a airbag type charge to electronically deploy a 3rd chute for emergency stops. Could be activated by tip over switch or by push button if for what ever reason the 2 primary chutes failed. Take note this would be in a vehicle that would reqire the tail to split open to expose the chute tubes (411 ish). I would plan that the emergency chute would be aligned with a burst panel in the tail that would allow the chute to breach the tail section without opening.
Would use a carbon fiber high pressure tank with end cut off for the tube (rated at 4500psi) similar to below:
(http://www.ctico.com/lrg_tank.jpg)
Any thoughts or comments regarding this idea?
~JH
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You building a new car or is this for the Fiat?
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Is this to use instead of a pilot chute/spring? Are you going to be running an air shift transmission? :cheers:
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Just a bit if history summer brothers golden rod used 12 gauge shot gun shells I think now i am second guessing my self but I believe it was them. When we rebuilt the car there were different tail secsion to the car and some pic showed them to be a different color we later learned that the different color was to help the crew find the panels on the salt thought that was pertty cool
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Just a bit if history summer brothers golden rod used 12 gauge shot gun shells I think now i am second guessing my self but I believe it was them. When we rebuilt the car there were different tail secsion to the car and some pic showed them to be a different color we later learned that the different color was to help the crew find the panels on the salt thought that was pertty cool
Yes, I've heard the same thing.
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Have you looked into the BRS ballistic chute system? It is FAA certified for the Cirrus aircraft as well as many ultralights. I realize a certified system is costly and you want low cost. However, it might be worth a call to them about a non-certified, or prototype system. I think their patent is focused about their reefing device which is another good idea for LSR. I have been toying with the idea of a LSR ballistic chute for a long time. I think you have a very interesting idea and the use of an air bag charge is innovative. However, it will be challenging (especially the testing).
http://www.brsaerospace.com/brs_aviation_home.aspx (http://www.brsaerospace.com/brs_aviation_home.aspx)
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Have you looked into the BRS ballistic chute system? It is FAA certified for the Cirrus aircraft as well as many ultralights. I realize a certified system is costly and you want low cost. However, it might be worth a call to them about a non-certified, or prototype system. I think their patent is focused about their reefing device which is another good idea for LSR. I have been toying with the idea of a LSR ballistic chute for a long time. I think you have a very interesting idea and the use of an air bag charge is innovative. However, it will be challenging (especially the testing).
http://www.brsaerospace.com/brs_aviation_home.aspx (http://www.brsaerospace.com/brs_aviation_home.aspx)
Looks like spam to me.
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When I read "burst panel" I immediately thought of the SFI panel. However, everything I have seen would most likely be too small for your envelope. What were you planning on using?
It also appears you are considering "blasting" the chute out of the tube (bottle). Another consideration would be to use a shuttle to pull the chute out. It might be more orderly, and predictable. Also, easier to define the burst panel dimensions to accommodate a fixed-sized shuttle rather than an expanding chute.
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Looks like spam to me.
Why would say that! Do yo have any idea what this post is about or what Jonny is trying to do? :-P
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Careful Tman. That one's totally legitimate, plus Saltfever's a really active participant on the forum. Read the whole thread.
Pete
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Saltfever, how'd you become a newbie all over again? :?
Pete
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Jon fixed a problem in the dbase that prevented me from modifying my profile data. The problem got fixed but the link to my 400+ posts was broken rendering me a newbie. :cry: :-D
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Jon fixed a problem in the dbase that prevented me from modifying my profile data. The problem got fixed but the link to my 400+ posts was broken rendering me a newbie. :cry: :-D
Jon found a way to make somebody a virgin again? He'll be rich! RICH I say!! :lol:
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This can be where you get into tricky territory. I understand the concept but there is a lot of other things that can go wrong. I have my jump wings so I know a thing or two about chutes. One thing that can go wrong is you cause a horseshoe. Thats where you have the main chute that failed to deploy but is open, and you deploy a reserve on top of it. Now some resistance is better than no resistance but at this point your going to create unwanted side forces.
If your going to do this, you would need to decide that it should only be pulled if the mains fail to open. Or you will want to design a cut away system to release the old chutes and make sure you don't just throw yourself into a roll.
What you should really do is use explosive bolts. instead of using a pilot parachute. Have two explosive bolts on the panel. Design the panel to pull the parachute when it comes off. A good layer of wadding will protect the parachute, and you will have to play around with what you can use but just rigging the parachute to open once the hatch is pulled open might be your best bet. Otherwise you can design it so the pilot chute pulls the main out once it catches a hint of air.
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DocBeech, great idea! Wouldn't it be ideal if the main chute were somehow attached to the burst panel? Or at least the cut away system was? Then, when the bolts are blown, everything is done at once.
Just thinking that some times things happen fast, and if a guys in trouble, too many steps may be cumbersome, and spell disaster.
Just an idea.
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Man o man, see what happens when I try to help? No, I can't implant that little bit of tissue. The control board I have lets me get rid of spambots and ban FR -- but not reconfigure your sweetheart. Saltfever's right, though -- in the process of fixing some stuff on his registration -- he lost his posts. Really.
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Careful Tman. That one's totally legitimate, plus Saltfever's a really active participant on the forum. Read the whole thread.
Pete
Little on edge here, there has ben a concentrated effort by spammers in the last few days and we have been dealing with them on other boards. Miniscule post count at the time of his posting made me think that. Purely coincidence. I would rather call out spam and be wrong. Which I was on this count.
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Spammers hit this board pretty regularly too but between Slim and Stainless they disappear almost as quickly as they appear. Keep up the good work Guys. :cheers: :cheers: :cheers:
Pete
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Thats where you have the main chute that failed to deploy but is open, and you deploy a reserve on top of it. Now some resistance is better than no resistance but at this point your going to create unwanted side forces.
It is my plan that the only reasons this emergency chute was deployed IF the split tail 'air brake' failed to open OR in the event of a tip over (potentially also disabling the split doors, not to mention they could not react fast enough) to prevent a pencil roll condition. If there was the condition that it was used would mean the primary chutes were not released. (*I guess you could if they both failed but not even considering that. Also the same principles of multiple chute release applies to all vehicles with multiple chutes).
I used the term 'burst panel' but that may be the wrong thing to call it. The panel would be 'soft spots' un obstructed with structural elements in the ends of the tail section that would allow the chute to blow though without opening.
-Clearly the cute itself is not a suitable projectile-
I was going to solve this by using an aluminum 'shell', capped on one end and would fit inside the main tube (the open end faces rearward and contains the packed chute). The charge would be behind the shell. The shell itself, containing the chute would entirely eject rearward and once out the chute would pull out of the shell, in similar fashion to the kids fable of tying a string to your tooth and attaching it to a door and slamming the door to painlessly removing a loose tooth.
~JH
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I like the Idea but I recommend that you link the system to eject the main chutes when used. I also don't recommend this as an airborne device. You will have less impact if you allow the vehicle to reach the ground in a roll than if you open the chute in mid air and throw the vehicle into the ground violently.
Same concept as in parachuting. You "tuck and roll" when you hit the ground on a T7A parachute. This should only be used when you are very close to the ground.
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How about stuffing the chute in an old 8" howitzer brass and cutting the charge at only 1 white bag :evil: :-o:-D (I think, been over 40 years since I had to calculate a fire mission). Sorry, I couldn't pass this up. I have nothing else to offer. vic
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(edit . . . ) The charge would be behind the shell. The shell itself, containing the chute would entirely eject rearward and once out the chute would pull out of the shell, ~JH
I assume you will contain the shell with the car? (e.g. your "tooth" example). I doubt tech will allow debris on the track even though deployment is to prevent an accident which might add even more debris.
Jonny, have you had experience with air-bag explosives? I think your idea is very interesting as a source of energy. There could be other applications but I have personal reservations only due to my inexperience with them. I would like to learn more.
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I hope you paid attention in math and chemistry:
Inside the airbag is a gas generator containing a mixture of NaN3, KNO3, and SiO2. When the car undergoes a head-on collision, a series of three chemical reactions inside the gas generator produce gas (N2) to fill the airbag and convert NaN3, which is highly toxic (The maximum concentration of NaN3 allowed in the workplace is 0.2 mg/m3 air.), to harmless glass (Table 1). Sodium azide (NaN3) can decompose at 300oC to produce sodium metal (Na) and nitrogen gas (N2). The signal from the deceleration sensor ignites the gas-generator mixture by an electrical impulse, creating the high-temperature condition necessary for NaN3 to decompose. The nitrogen gas that is generated then fills the airbag. The purpose of the KNO3 and SiO2 is to remove the sodium metal (which is highly reactive and potentially explosive, as you recall from the Periodic Properties Experiment) by converting it to a harmless material. First, the sodium reacts with potassium nitrate (KNO3) to produce potassium oxide (K2O), sodium oxide (Na2O), and additional N2 gas. The N2 generated in this second reaction also fills the airbag, and the metal oxides react with silicon dioxide (SiO2) in a final reaction to produce silicate glass, which is harmless and stable. (First-period metal oxides, such as Na2O and K2O, are highly reactive, so it would be unsafe to allow them to be the end product of the airbag detonation.)
The airbag's acceleration (a) can be computed from the velocities and distance moved (d) by the following formula encountered in any basic physics text:
vf2 - vi2 = 2ad.
Substituting in the values above,
(89.4 m/s)2 - (0.00 m/s)2 = (2)(a)(0.300 m)
a = 1.33x104 m/s2.
The force exerted on an object is equal to the mass of the object times its acceleration (F = ma) ; therefore, we can find the force with which the gas molecules push a 2.50-kg airbag forward to inflate it so rapidly. 2.5 kg is a fairly heavy bag, but if you consider how much force the bag has to withstand (see Figure 5), it becomes apparent that a lightweight-fabric bag would not be strong enough. Note: In the calculation below, we are assuming that the airbag is supported in the back (i.e., all the expansion is forward), and that the mass of the airbag is all contained in the front face of the airbag.
F = ma
F = (2.50 kg)(1.33x104 m/s2)
F = 3.33x104 kg·m/s2 = 3.33x104 N.
Pressure is defined as the force exerted by a gas per unit area (A) on the walls of the container (P = F/A), so the pressure (in Pascals) in the airbag immediately after inflation can easily be determined using the force calculated above and the area of the front face of the airbag (the part of the airbag that is pushed forward by this force). Note: The pressure calculated is gauge pressure.
The amount of gas needed to fill the airbag at this pressure is then computed by the ideal-gas law. Note: the pressure used in the ideal gas equation is absolute pressure. Gauge pressure + atmospheric pressure = absolute pressure.
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Doc, you took the words right out of my mouth.
My experience with airbag detonators comes from when I was recycling metal (used oil filters) by taking the stuff to a local cupola furnace. The main input to the furnace was defective airbag detonators and spent ones. They'd be dumped into the top of the 50-foot tall thing -- looks like a fat chimney -- that was heated by natural gas at the bottom. The metal would soften and melt, and in the meantime the detonators that weren't exploded would proceed to do so. It made for a merry time when standing at the top of the thing -- "boom", "crump", "KA-pow!", and so on. By the time the detonator was molten and reached the bottom, where it was drained into ingots -- the nasty stuff had been burned, detonated, and filtered through the baghouse.
Yes, the place was eventually shut down due to EPA/Dept. Environmental Quality violations. No liability for me, though -- I was just a customer of the service.
Further deponent sayeth not.
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In my lakester I use a kicker spring at the base of the canister that my parachute bag is stuffed into. I use a pilot chute to
begin the release of the parachute bag when the trap door opens. I've filmed the deployment action and it works very well.
On the NAE I use a Chevy steering wheel deployment canister, fired with a 12 vdc charge when I push the button. I also
open the trap door with a solinoid. There is a micro switch on the solinoid link that prevents the charge from going off before
the door is opened. I use a pilot chute to keep the bag oriented so the 150' riser line will deploy before the bag hits the end of the line and the bag strips off and allows the chute to stream out and open. I bundle the lines with rubber bands to keep things organized and in order. The parachute bag and line are all packed into one bag and the total weight is 30 lb. The charge will blow the bag about 30' in a static test. We've used that concept in most of our 30 test runs and it works very well. We've filmed the deployment with a high speed camera and are happy with the results. It works for us, it may not be something you would use but I'm happy with how it works on our car.
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Very nice, DocBeech. There is more than gas laws involved and its nicely laid out which can help with other mechanisms. :-)
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So how did you plan to incorporate your "manual backup release" ?
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So how did you plan to incorporate your "manual backup release" ?
Kiwi, the ballistic chute would be deployed by inertia switch or manually by pushing a button and only used if the main chutes failed to open (and this could be a problem if the air brake doors did not extend, yet the vehicle remains upright).
The primary intent is to prevent a pencil roll condition but also could be used to slow the vehicle with minimal damage if all other slowing methods fail.
~JH
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For a backup system, I use a completely redundant second parachute system. If the second one doesn't work, I look for
a brine pond.
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Im not sure you could react fast enough for this to work. If you include the G forces involved in a failed parachute opening. It would need to be an automated system if you are trying to cut away a chute the only partially opened, or tangled. If this system is for the sole purpose of my main chute had no reaction at all, then you would be ok. But if your trying to prevent a roll from a tangled/partial opened chute then its a bad idea. You would need to have an incredible reaction time and strength if your chute opened funny and sent you into a side g pull.
Honestly I would only recommend this system as a reserve for a failed main. Not to prevent anything, or to try to counteract a chute that doesn't open properly.
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Im not sure you could react fast enough for this to work. If you include the G forces involved in a failed parachute opening. It would need to be an automated system if you are trying to cut away a chute the only partially opened, or tangled. If this system is for the sole purpose of my main chute had no reaction at all, then you would be ok. But if your trying to prevent a roll from a tangled/partial opened chute then its a bad idea. You would need to have an incredible reaction time and strength if your chute opened funny and sent you into a side g pull.
Honestly I would only recommend this system as a reserve for a failed main. Not to prevent anything, or to try to counteract a chute that doesn't open properly.
How about if the main chute was automatically cut away if the back up was deployed? Seems that could be rigged. Wayno
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How about if the main chute was automatically cut away if the back up was deployed? Seems that could be rigged. Wayno
I understood that part. That part would work just fine. Its the emergency back up idea that I would like to shoot down. If you have a chute that failed to fully open, or tangled on its way how would you teach the system that you only got a partially opened chute.
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By the time you figure your chute didn't open or is tangled you have gotten to the mud and will slow rapidly at that point.
The only fool proof way to ensure that you have a good deployment is to leave the start line with the chute out of the pack. I have witnessed this method.
DW
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I'm not sure any of this would get past Homeland Security. :evil: :cheers: :cheers:
Doug
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If you have a chute that failed to fully open, or tangled on its way how would you teach the system that you only got a partially opened chute.
Depends on how fancy you wanted to get. Photo cell in the back of the chute pack to detect that the chute pack is open, (who let all the light in) and a G meter to tell you that you are not getting the deceleration you should would be at the top of my list. The backup video cam looking aft is also a nice backup so the driver does not have to wonder what is going on.
Larry
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That's a lot of things to look at while you're still trying to stay on course -- and you've probably spent 10 minutes a year under power and recognizing all the other controls. You can spend hours in the garage memorizing them, but at over 200 there seems to be other things that distract you. At least for us old farts.
Stan
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That's a lot of things to look at while you're still trying to stay on course -- and you've probably spent 10 minutes a year under power and recognizing all the other controls. You can spend hours in the garage memorizing them, but at over 200 there seems to be other things that distract you. At least for us old farts.
Stan
I can feel the chute deploy, but as an extra I do have a large convex rear view mirror so I can see behind me,, like the Chute or Push Truck,, or stuff behind me when backing out of the trailer etc...
No time to look for fancy stuff in the cockpit at speed.
Charles
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Was not suggesting "lots of stuff" to look at, just great big idiot lights that come on after the chute release to confirm the chute pack opened and you have deceleration.
The rear view monitor would only be something to look at after all the other important items have been taken care of, just like the rear view mirrors.
You have one green idiot light come on when the chute pack opens, telling you that you got a release and the chute pack is open, and a second big red idiot light that only comes on when the green light is on, and no negative G's from a fully blossomed chute. That could be as simple as a ball bearing in an inclined tube that would slide forward under negative G's and close a contact.
Keep this sort of stuff cave man simple.
Larry
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When you are traviling at high speed you don't have a lot of time to think about it. You better guess the instant things start to go nuts. All of the lights and bells wont help.