Airbag trigger points
Airbag trigger points
(OP)
Does anybody here know the forces necessary to set of an airbag, or more to the point, the safe limit in use, so as to avoid accidental discharge.
The reason for the question, is that on a recent trip to a desolate area of outback Australia, I assisted a mid sized 4 X 4 bus which was bogged.
It must have weighed 5 or 6 tonnes. I was in an Isuzu 4 X 4 station waggon that weighs 2 tonnes.
When I hit the end of the rope, at about 35 kph (20mph) the rear wheels were pulled from the ground, and the impact was enough for me to suddenly think "Oh no, the air bag".
We retrieved the bus, to everyones amazement, and no damage was done.
How hard could I hit the rope without risk of setting off the airbag.
Why isn't the fuse that disables the airbag clearly marked.
Why arn't there warnings that the airbag might deploy in such violent manovers.
This location was so isolated, that it might have taken up to 48 hours for help to arrive
The reason for the question, is that on a recent trip to a desolate area of outback Australia, I assisted a mid sized 4 X 4 bus which was bogged.
It must have weighed 5 or 6 tonnes. I was in an Isuzu 4 X 4 station waggon that weighs 2 tonnes.
When I hit the end of the rope, at about 35 kph (20mph) the rear wheels were pulled from the ground, and the impact was enough for me to suddenly think "Oh no, the air bag".
We retrieved the bus, to everyones amazement, and no damage was done.
How hard could I hit the rope without risk of setting off the airbag.
Why isn't the fuse that disables the airbag clearly marked.
Why arn't there warnings that the airbag might deploy in such violent manovers.
This location was so isolated, that it might have taken up to 48 hours for help to arrive
Regards
pat





RE: Airbag trigger points
I've just looked through the airbag schematics for an EF Falcon.
Typical crash pulses are in the 20 to 80 g range at the sensor(s), which is obviously far more than you can generate with a rope. So far as I can tell if 2 out of three crash sensors are activated then the airbag goes off. However, anecdotally, naughty people can set them off by hitting the bumper in a particular way with a baseball bat.
We deactivate the airbag by disconnecting it in the steering wheel and adding a dummy load, but then we usually want the electric side of it to work. There are a total of four fuses in the system, at least one of which is in the passenger compartment fusebox, and labelled as such. I imagine that removing this will generate a fault code and disable the airbag system.
Cheers
Greg Locock
RE: Airbag trigger points
Thanks for the info, it is reassuring. If it had been 5 or less, I would really worry.
The last point was to make the point that it was necessary to recover the vehicle, rather than go to get more help.
I know you can still drive the vehicle after deployment, but I certainly would rather avoid the expense and injury (even if only minor) that a deployment would cause.
Regards
pat
RE: Airbag trigger points
Hello, I was searcing the old posts and ran across this one. Since I am doing some customizing on a vehicle which includes removing the airbag. Could you please let me know what the dummy load you referred to is and what the elctrical values of this load are. Any help would be appreciated.
Thank you,
Trek Lawler
RE: Airbag trigger points
Anyway, there should be sufficient clues in the workshop manual for you to work out the required resistance.
Cheers
Greg Locock
RE: Airbag trigger points
Are there any other helicopter owner opperators out there that think this would be a useful addition to helicopters?
Are there any engineers with any comments about this? I am wanting to develope a simple system based on a 3 axis accelerometer and automotive style glare shield mounted airbag.
Obviously, this system will need to be FAA approved on a no hazard basis and it must function correctly.
Nigel Waterhouse B Eng (Hon's)
Can-Am Aerospace,LLC, Canadian Aircraft Certification Centre
www.canamaero.com
RE: Airbag trigger points
My concern about an air bag in the cockpit is the event of a malfunction in the airbag system which would render the aircraft difficult or impossible to fly. Getting a light rotor wing aircraft into autorotation can be difficult enough without a loose-floppy airbag in your way.
I remain,
The Old Soldering Gunslinger
RE: Airbag trigger points
It does not work in passenger cars due to fashion implications and driver discipline or lack thereof. I imagine these factors should be less apparent where the operator needs an aircraft licence.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Airbag trigger points
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Airbag trigger points
In a car just before the airbag goes off, the car is almost certainly already in a position where control could not be be regained, and the only strategy is heavy braking with a reasonable chance of not hitting anything else at high speed, but in an aircraft, there can be time to attempt to recover control before hitting the ground at high speed, so long as the pilot is not hampered.
If held in place by a 5 point harness, and with some head restraint built into the seat, I would think should give as good a protection as an airbag, and it continues to work in subsequent impacts.
I should qualify this as being thoughts and personal observations only, with no hard data to support it.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Airbag trigger points
You say that you hitted the end of the rope at 35+km/h (an elastic rope I suppose) and you want to hit it even faster? You dont really want to do that!! Trust me, I ripped out the anchorage point of a series III Landy only at 40 km/h and it went trough my back door (I own a Landy too) at one zillion km/h of speed, destroying my back door AND a 4 gallon water filled Jerrycan! I still have cold sweat about that.
RE: Airbag trigger points
how much of the desired benefit could you get from some sort of harness power retraction unit (a la Martin Baker)?
A.