Lancair Live!

Hello Everyone,

Great info here.

The system with pictures looks like the normal way most are installed. My system takes approx 15 seconds to inflate and will often chirp occasionally. However, recently it began to churp every 10-15 seconds. This would indicate a leak somewhere. With alligator leads I connected the door to the airframe with the door open and was able to pressurize the seal without damage as the pump shut off normally at approx 20psi. I could not find any leaks with soapy water. Then I began the process of elimination in order to isolate the problem to the tubing, pump, door seal, or pneumatic toggle switch, etc. You can isolate each component by replumbing with the spare tubing and activating the pump to see if the churping goes away. Once I took the toggle switch out of the equation (bi-passed it with the tubing) the chirping went completely away. Viola, ...there was the problem! A new $35.00 toggle valve is on its way. It never came to my mind that the toggle switch would leak. Make sure you check there as I now understand they will wear out and begin leaking over time.

On another note, If you have a pump running, Caution... do not allow a motor to run continuously as it may overheat and cause a fire.

In the past I have also repaired a pin hole leak in the door seal with silicone. Please don't do this! It worked for a little while but blew out after several flights at FL220. This is not a good thing when at high altitudes and in weather!

Hope this helps.

Call me with other questions,

... George, 303-995-5501

That is great story George! I would not have guessed that the silicone would’ve gave away so easily. Maybe you should’ve use that stuff that they sell on TV called flex all? It fixed the leak in my Koi pond.


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George,
Designation and source for valve? What do you use for pinhole sealant? There was a reference to Proseal in another thread but the particular compound no longer seems to be available. Thanks
Best,
Tom

George Rosel wrote: ↑Wed Nov 15, 2023 6:13 pm

…..In the past I have also repaired a pin hole leak in the door seal with silicone. Please don't do this! It worked for a little while but blew out after several flights at FL220. This is not a good thing when at high altitudes and in weather!

Hope this helps.

Call me with other questions,

... George, 303-995-5501

We developed a pinhole leak in our baggage door seal in 2014. It was repaired with a mixture of silicone and ground up fiberglass matt. This October another pinhole leak developed in the seal. It was temporarily repaired again. I decided to retire the seal and a new one was installed at condition inspection.

This is the pneumatic toggle switch I ordered. See attachment...

... George

One thing John Cook AND Brad Simmons recommended to me while building and fitting the door to the seal was to actually measure the gap between the deflated seal and the door frame (from inside the plane). I’ve fitted door seals on two IVPT’s and both had gaps approaching 1/8” to 3/16” (.120” - .180”). A standard tongue depressor is .060” (for reference) and I actually used a .030” and .040” feeler gauge to get my gaps fitted nicely (gap had to meet those dimensions as minimum and maximum). I filled the door frame (can’t add material to the door since by this time the door seal is glued on) as needed to get that consistent narrow gap.

My door seal runs for no more than 10 seconds on initial inflation and would bump once in the first half hour (colder temps) for a second or two. I was always aware of my door seal pressure by observing the gauge located in the window sill.

I believe the required inflation diameter of the seal, based on door gap, probably has more effect on door seal life than most other factors other than age.

Tom

That’s a really nice explanation Tom,,


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Gang,

I have found it hard to chase small leaks with soapy water.

I suggest you remove the inside door panel so you expose tubing, pump, check valve, psi regulator and phneumatic toggle switch, etc. Then while you are inside the cabin, close the door and inflate the seal. The PSI regulator should be set to inflate the door seal and shut off in about 10-15 seconds (equating to approx. 12-15 psi if you have a guage plumbed in the system) and 45-90 seconds between chirps is acceptable. If you have a leak it is easier to find if you eliminate each component one by one (process of elimination). You will need some extra tubing and fittings, etc. I recently found when I took the toggle switch out of the system then inflated the door seal my leak went away. There was my problem!

Ordered a new toggle switch for about $30.00. Never thought the toggle switch would be leaking.

... George