Rick I don't want to sound argumentative but the total force on the cone is
1/2 the force in the bag, since that force is applied to 2 arms, and thence
to a 2 wheels. The force on the cone can be calculated by multiplying the
area of the end of the bag times the pounds per square inch pressure(100PSI
or so). Easiest way to calculate it is to put a scale under each tire, and
that would indicate the total force on each cone in a static condition.
Dynamically the load on each wheel changes as the coach moves back and forth
etc.
With regard to the danger of using plastic cones versus aluminum. There
could be a strong case made for the use of plastic if in fact it had the
proper physical properties. There are some plastics that are stronger than
aluminum and able to withstand enormous impacts without failing. I for one
would be interested in what Wes Coughlan has to say on this subject.
With regard to exploding cones. It sounds like another myth starting to
explode. How many coaches are still running with the original plastic
cones. I talked to a visiting GMCer just 2 months ago, and his 1975 had
both the original bags and cones, all still in nice shape. How many verified
explosions have we found? If they have not failed in 20+ years why are we to
believe that they are ready to now? Is this perhaps just another marketing
gimic to sell more cones and bags since most would not buy the cones alone?
I don't know, but we should not rush like frightened lemmings and change
them. Stop and think. How many put a piece of 2X6 under their wheels when
working on the coach. Are you worried about it exploding also? 2000 pounds
on the cone is not a lot considering the area.
Me thinks that someone maybe making a mountain out of a molehill. just my
opinion but I think it is another Archism.
>
>> Dear gmc gang: How does a piece of solid plastic blow up? What pressures
>> are being exerted. Does the air bag blow? I'm concerned, I'm a 73 with
>> plastic!
>
>Arden,
> The force involved is whatever force the plastic cone is trying to transfer
>to the bogie arm. Or. to look at it another way, the ~100 psi air pressure on
>the inside of the cone, PLUS the force transferred from the bag to the cone.
> Fwiw, the GMCMI newsletter (vol. 50, 1995, IIRC) stated that the "black
>plastic cones" were "dangerous". From the confirmations we've received here,
>I tend to agree. I, for one, would never reuse a plastic cone when replacing
>an air bag, and would seriously consider replacing said cones in any case.
> My .02.
>
>Rick Staples
>'75 Eleganza
>Louisville, CO
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
1/2 the force in the bag, since that force is applied to 2 arms, and thence
to a 2 wheels. The force on the cone can be calculated by multiplying the
area of the end of the bag times the pounds per square inch pressure(100PSI
or so). Easiest way to calculate it is to put a scale under each tire, and
that would indicate the total force on each cone in a static condition.
Dynamically the load on each wheel changes as the coach moves back and forth
etc.
With regard to the danger of using plastic cones versus aluminum. There
could be a strong case made for the use of plastic if in fact it had the
proper physical properties. There are some plastics that are stronger than
aluminum and able to withstand enormous impacts without failing. I for one
would be interested in what Wes Coughlan has to say on this subject.
With regard to exploding cones. It sounds like another myth starting to
explode. How many coaches are still running with the original plastic
cones. I talked to a visiting GMCer just 2 months ago, and his 1975 had
both the original bags and cones, all still in nice shape. How many verified
explosions have we found? If they have not failed in 20+ years why are we to
believe that they are ready to now? Is this perhaps just another marketing
gimic to sell more cones and bags since most would not buy the cones alone?
I don't know, but we should not rush like frightened lemmings and change
them. Stop and think. How many put a piece of 2X6 under their wheels when
working on the coach. Are you worried about it exploding also? 2000 pounds
on the cone is not a lot considering the area.
Me thinks that someone maybe making a mountain out of a molehill. just my
opinion but I think it is another Archism.
>
>> Dear gmc gang: How does a piece of solid plastic blow up? What pressures
>> are being exerted. Does the air bag blow? I'm concerned, I'm a 73 with
>> plastic!
>
>Arden,
> The force involved is whatever force the plastic cone is trying to transfer
>to the bogie arm. Or. to look at it another way, the ~100 psi air pressure on
>the inside of the cone, PLUS the force transferred from the bag to the cone.
> Fwiw, the GMCMI newsletter (vol. 50, 1995, IIRC) stated that the "black
>plastic cones" were "dangerous". From the confirmations we've received here,
>I tend to agree. I, for one, would never reuse a plastic cone when replacing
>an air bag, and would seriously consider replacing said cones in any case.
> My .02.
>
>Rick Staples
>'75 Eleganza
>Louisville, CO
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
