 Did altitude just blow out 2 MPS's?, Put the in my checked baggage...now won't hold vac. |
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| FlacaProductions |
 Aug 20 2025, 11:19 AM
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Senior Member  Group: Members Posts: 1,998 Joined: 24-November 17 From: LA Member No.: 21,628 Region Association: Southern California 
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Brought two of my 3 MPS back to L.A. from Indiana while I await the arrival of my LCR55A so that I could do some bench plotting and tuning only to find that neither one of the now holds any sort of a vacuum.
Both ran fine in the car before flight - just needed some adjustment. One has the factory plug replaced with a Tangerine model - the other is still factory sealed. Did being in the unpressurized cargo area in my checked baggage blow them both? That would really stink.... Brian |
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| ChrisFoley |
Aug 20 2025, 02:35 PM
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#2
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I am Tangerine Racing Group: Members Posts: 8,001 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None
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Here's what I thought of:
The reduced atmospheric pressure resulted in expansion of the aneroid cell, which pushed the diaphragm outward, like happens during use on overrun, but with more force. More than likely the diaphragms were close to failure already. They almost always fail at the edge of the supported perimeter area because the casting has a sharp corner there. |
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Posts in this topic
FlacaProductions Did altitude just blow out 2 MPS's? Aug 20 2025, 11:19 AM
flipb The cargo hold in modern jets is pressurized. The ... Aug 20 2025, 11:25 AM FlacaProductions They were well packed and padded.
F me. Aug 20 2025, 11:33 AM ctc911ctc Considering that the ALPS and the Rockies were tho... Aug 20 2025, 01:01 PM
emerygt350
Considering that the ALPS and the Rockies were th... Aug 20 2025, 01:17 PM ctc911ctc Thinking back I broke one by selecting PRESSURE ra... Aug 20 2025, 01:21 PM ctc911ctc
I think the danger would have been in the expans... Aug 20 2025, 01:36 PM JamesM
I think the danger would have been in the expans... Aug 20 2025, 09:33 PM FlacaProductions I just put two vacuum pumps on each one here in LA... Aug 20 2025, 01:17 PM FlacaProductions This might have just been a bridge too far for me. Aug 20 2025, 01:21 PM FlacaProductions that's the thing. no more diaphragms. Aug 20 2025, 01:23 PM burlybryan Your bag wasn't searched and the MPS's ... Aug 20 2025, 01:43 PM JeffBowlsby
Here's what I thought of:
The reduced atmosph... Aug 20 2025, 05:40 PM JeffBowlsby
Here's what I thought of:
The reduced atmosph... Aug 20 2025, 05:50 PM emerygt350 The whole thing is a sealed area. Two forms of mo... Aug 20 2025, 02:36 PM ChrisFoley
The whole thing is a sealed area. Two forms of m... Aug 20 2025, 02:37 PM FlacaProductions I’ll crack the unsealed one asap and report back... Aug 20 2025, 02:50 PM Spoke The MPS senses the difference in pressure from amb... Aug 20 2025, 02:53 PM emerygt350 The diaphragm itself is a sealed vessel. Containi... Aug 20 2025, 03:15 PM FlacaProductions Here's the pics.
First time I've had one o... Aug 20 2025, 04:50 PM FlacaProductions RE: Did altitude just blow out 2 MPS's? Aug 20 2025, 04:50 PM FlacaProductions AND....how do i put it back together?! Aug 20 2025, 04:57 PM rjames If the diaphragm isn't cracked and the seals a... Aug 20 2025, 05:06 PM FlacaProductions I could use some of that tequila right now. Aug 20 2025, 05:17 PM JeffBowlsby Post photos of the front/back of the diaphragm ple... Aug 20 2025, 05:20 PM emerygt350 You can test if the cell is doing what it should b... Aug 20 2025, 05:33 PM FlacaProductions I don't see any breaches. I've held it up... Aug 20 2025, 05:51 PM ChrisFoley
I've gently flexed it all around and don... Aug 20 2025, 06:09 PM FlacaProductions No cracks. I would think that it’ll tear or clic... Aug 20 2025, 07:41 PM FlacaProductions Well. It’s back together and it’s holding SOME... Aug 20 2025, 08:59 PM Olympic 914
Well. It’s back together and it’s holding SOM... Aug 21 2025, 08:46 AM Superhawk996 Grease the paper gasket (very lightly) that is a f... Aug 20 2025, 09:18 PM IronHillRestorations My guess is your suitcase got tossed by baggage ha... Aug 21 2025, 05:25 AM bdstone914 I once shipped a good MPS and it was dead on arriv... Aug 21 2025, 05:40 AM FlacaProductions Rats.
Both of these were shipped to me and they w... Aug 21 2025, 07:18 AM |
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