| Author |
Message |
Dave Wilson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 05, 2006 - 10:57 pm: | |
Right in the craves above rear drive axle wich the top of the shock mounts to i have air leaking what is the best solution for this problem. |
Bill K
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 05, 2006 - 11:21 pm: | |
Sounds like your air beam is leaking. Block off the beam and get the plates and bags which is made for this fix. Iam sure some one will tell you where you can get these. I think Mohawk is one source. |
califbob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 05, 2006 - 11:21 pm: | |
what kind of bus is it? |
Dave Wilson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 9:07 am: | |
Mc9 |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 9:51 am: | |
Is there much ride degradation or any other differences when one converts away from the air box beams , has anyone decided to do the conversion kits and added a ping tank to make up for the lost surgeability provide by the box beam. One other though I had, if those air box beams are leak form rust, how certain can one be that they are sound enough to keep taking the loads impressed by the conversion kit, as they are now even weaker without air pressure inside with regards to compression forces. |
motorcoach1
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 12:50 pm: | |
go to bernhard.com and there are some photos of a repair. this will give you an idea of what you might want to consider doing |
David Hartley (Drdave)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 12:54 pm: | |
The airbox is a volume-based system, The higher the volume the better the bounce from compression changes.
The air has no significant factor in the structural strength of the air box.
I have had to change the blocking plates on my MC9 and NJT had already installed them previously and I had the old ones corrode from moisture in the air system. The same moisture that gets into the air beams and makes them leak.
As far as the difference in ride, I haven't noticed any difference. As far having to worry about dirty air rusting the airbox framework out, I would rather replace a few aluminum plates in 20 years + than have the frame collapse from rusting inside out.
My.Opi.... |
motorcoach1
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 1:12 pm: | |
so true David . the plates are the trick and if you want more air just install another air reservoir and be sure to put a check valve and a dump drain in |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 1:30 pm: | |
MCI 1 I didn't have much luck serfing for bernhard.com. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 1:58 pm: | |
http://www.bernhardbus.com/DEFAULT.HTM
Richard |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 2:18 pm: | |
thankyou kindly |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 3:00 pm: | |
May MB or one of you other Structural engineers can offer you opinion on the integrity to those Air Box Beams on the MCI (my only flavor at this time is MC 8). It is not a question that the whole structure must be sound enough to transfer the weight when modified (due to corrosion induce leaking and possible fatigue cracks from reduced strength), the question still remains with me "without the air pressure in the box", it's integral strength is also reduced much like crushing a full and caped soda can is much harder than a empty beer can or grabbing a jet aircraft at high altitude and squeezing to hard to over come the inertia and stop it in flight is safe , but once one of the stewardess opened the cabin door to see " what the hold up was", and the fuselage got all squishy and weak and collapsed suddenly, I had noticed. (ha ha, just trying to keep every one awake through the details as I have a very gentle touch when I grab jets out of the sky and no passengers were ever hurt all those times I needed to take a closer look). |
Ed Jewett (Kristinsgrandpa)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 3:45 pm: | |
How big was the jet?
Ed |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 5:27 pm: | |
The one that collapsed like a "American Beer" can, Galaxy Class (I think the civilian designation is C-5, whew no fatalities on this booboo. Whew, good thing they don't hold village idiots liable or accountable! |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 6:34 pm: | |
An aircraft designer cannot rely on the "additional" stiffness generated from a pressurized fuselage because of the consequences that may occur if there's a loss of pressurization.
The beams suffer more from exterior problems than interior, since diligent air tank draining and air dryer maintenance would pretty much reduce corrosion to negligble levels. IMHO, it's the fiberglass caps in the wheelwells that are the problem |
JR
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 8:26 pm: | |
The air beams only have 55-60 lbs psi in them. Doubt this would have a demonstrable effect on the strength of the frame/airbeam section. There are thousands of airbeams that have been blocked off and rolling-lobe airbags installed. Never heard of a problem. 86 and up MC9s all have rolling lobe airbags as standard equipment. No air beams.
If the shock mounts are rusting out, may be necessary to repair the mounts.
JR |
Kyle Brandt (Kyle4501)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 9:59 pm: | |
To put some light on air beams:
The air bags use a volume of air in them to create the spring. As the bag is compressed, the air pressure increases.
For the same movement:
A high rate of air pressure rise gives a high spring rate.
Conversely, a lower pressure rise gives a lower spring rate.
This is where the air beam comes in. There is a very large hole between the bag & beam that effectively increases the volume of air in the bag, making the volume change (for a given deflection of the bag) smaller and thereby reducing the pressure rise and provides a softer ride.
The plates are relatively thin and there is a small air fitting to connect to the suspension system. These small fittings will reduce the flow of air such that any extra volume outside the air bag is insignificant and will not soften the ride.
My 1954 4501 ‘Almost Nuts’ has the block off plates. I think it rides very well. I can not imagine how much better it would ride with functioning air beams!
kyle4501 |
Dave Wilson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 06, 2006 - 10:29 pm: | |
I have went a head an ordered plate bag and supplies to fix the leak but i do also think i should get that section cut out replaced i do not want the rust to spread .These Mc9s are very reliable machines i intend to have updates done on them as i can afford i was talking to the fiberglass people said they have a fellow that does update installs in Edmonton that would work real well for me. |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 07, 2006 - 6:02 am: | |
"An aircraft designer cannot rely on the "additional" stiffness generated from a pressurized fuselage because of the consequences that may occur if there's a loss of pressurization."
Additionally the aircraft would not be pressurized on takeoff , the heaviest load with contact to a rough runway.
This is so the aircraft can be evacuated, with modern plug type doors.
Most folks that have PLATED over the origonal air beams , (use the kit) can not tell the difference in the ride.
Sometimes "fancy & excellent Engineering" may just be a sales tool , or mental masterbation.
FAST FRED |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 07, 2006 - 10:10 am: | |
That is the inherent fault of $sitting behind a desk to much (so I am learning) you can't just pick up a broom to look busy and feel useful so you must resort to "other measures" to remain "satisfied" and remain at your desk-hence$ I suspect "design gone wild".
$Just try balancing on one of those flimsy American Beer can's after it has been opened$ some day and you'll understand what I am talking about (don't forget to adjust for bornelis #1 law of uncompressablilty of that bubbly yellowy liquid inside the can that some call good beer) |
Kyle Brandt (Kyle4501)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 07, 2006 - 12:23 pm: | |
I think that closing the hole is a wise idea. There is sufficient metal to carry the load since it just started leaking, so I'd just seal the hole with a good undrecoating paint.
kyle4501 |