Spar top inspection

[mwilton1]

Good Morning Folks,

Since we have been digging into the Mooney to fix the trim switch and AP, I thought I would ask another question. We have cold air coming into the cabin from under the floor. From a discussion with another Mooney owner, it is a tin foil tape issue on top of the Spar. Apparently it degrades and peels off, allowing cold air from outside to stream in under aircraft, come up near the spar and come through the rear seat belt attachment points. He said that they put new tin foil tape on the top of the spar and this stopped the issue. No problem in the Summer as it is great cooling, but in -30 degree C weather in the winter, there is a pronounced cold air on the back of your neck.

Thanks,

Mike

[MB65E]

What’s your question?

-Matt

[mwilton1]

Looking for some guideance on the best way to access the top of the spar. Access panels from under the rear seat?

[PT20J]

Remove the rear seat. I believe that the factory used duct tape. Some people use aluminum tape, but it is hard to remove aluminum tape as it tends to tear into little pieces, the adhesive being stronger than the tape. 3M General Purpose Adhesive Cleaner will loosen the adhesive. The wing roots are also duct taped closed behind the interior trim panels and the dust boots on the landing gear retract tubes in the wheel wells are another source of air leaks. Also, the door seal along the bottom often leaks air if it is old and compressed.

If you are going to remove the rear seat and retape the inspection covers, I'd take the time to remove them and inspect the area between the front and rear spars for corrosion.

Skip

[MB65E]

Airlines use this nice fiberglass baggage tape. It’s also used in fuel bays to prevent chafing of bladders.

spruce sells It.

-Matt

[mwilton1]

4 hours ago, PT20J said:

Remove the rear seat. I believe that the factory used duct tape. Some people use aluminum tape, but it is hard to remove aluminum tape as it tends to tear into little pieces, the adhesive being stronger than the tape. 3M General Purpose Adhesive Cleaner will loosen the adhesive. The wing roots are also duct taped closed behind the interior trim panels and the dust boots on the landing gear retract tubes in the wheel wells are another source of air leaks. Also, the door seal along the bottom often leaks air if it is old and compressed.

If you are going to remove the rear seat and retape the inspection covers, I'd take the time to remove them and inspect the area between the front and rear spars for corrosion.

Skip

Thank you Skip, that is exactly what I was after. Really appreciate it.

Mike

[Yetti]

So probably/maybe.   The whole cabin is sealed from the outside by tape.  from the nosewell to back by the spar under the seat.  If it is factory it was duct tape.   If someone spent a day removing the duct tape they may have replaced it with alum foil tape.    Mine has a big ole vent on the outside to let air out.

[mwilton1]

Hi Folks,

We got our airleak sorted out this annual. Seems we had a slight weeping from the seals on the gaskets on fuel lines coming into the cabin (didnt smell it so not sure if it was super small or maybe I have had Covid for 2 years). We fixed the small weep and found a lot of the old duct tape along the cabin walls / spar was deteriorated and missing. Cleaned it all up, resealed the gaps and she is working perfectly. Thank you to everyone for your help on the forum. Great group!

[carusoam]

Great follow-up mw!

Thanks for sharing the details.

You will enjoy the leak free cabin when it comes time to heat it….   
 

+1 for replacing the old tape…

Best regards,

-a-