Thread Sealing? Use Cases?

[Pinky]

Dear all,

Recently, I stumbled over the YouTube video How Its Made 07 Aircraft Engines, which shows the use of a thread sealing (correct wording?) at time index 1:10 for the crank cases of an aircraft engine. What are the typical applications for such a type of sealing, i.e. can they be used for car engines as well? What are the advantages or disadvantages, respectively?

Many thanks!

Philipp

 

[earlyre]

for anyone not wanting to set through the video themselves
they refer to applying a "gasket sealant" (looks like good old contact cement to me), then in that bead of sealant apply 2 single silk threads to "act as gaskets"

I know weight is an issue with aircraft, but how much difference does a few ounces(for a proper gasket) make?

 

[The_Eric]

Originally Posted By: earlyre
for anyone not wanting to set through the video themselves
they refer to applying a "gasket sealant" (looks like good old contact cement to me), then in that bead of sealant apply 2 single silk threads to "act as gaskets"

I know weight is an issue with aircraft, but how much difference does a few ounces(for a proper gasket) make?


They're likely trying to keep it from squidging into the crankcase.

edit: After watching it, I'd say that they do it that way to keep the case halves square and tight together - minimal distortion.

 

[jbbwv]

It's nothing new in the Aircraft Engine world. I have used the same sealing thread along with sealant on numerious R1830 nose case seals to seal oil leaks. The same sealing method is used on Opposed engines. Works well and lasts a long time.

 

[tom slick]

Originally Posted By: earlyre
for anyone not wanting to set through the video themselves
they refer to applying a "gasket sealant" (looks like good old contact cement to me), then in that bead of sealant apply 2 single silk threads to "act as gaskets"

I know weight is an issue with aircraft, but how much difference does a few ounces(for a proper gasket) make?


A "proper gasket" would not set the case, cylinder, and bearing clearances correctly and would move as it compresses. Keep in mind that opposed engines with a split case don't have separate caps for the main and cam bearings: they are integrated into the case. Sealants are used because once the cases are assembled the sealant is microscopically thin.

 

[Pinky]

Thanks for the answers!

Am I deducing correctly, that in principle such sealings can be used for car engines, e.g. oil pan, as well but not for cylinder heads due to heat and pressure conditions?