Gear door gaps

[milotron]

Howdy,

My M20K is in for annual and I went in to see it while it was up on the jacks, primarily to operate the emergency gear release which I had not done before. ( works great by the way)

My main gear doors have some gaps in the front when retracted , and larger gaps in the back, trailing edges.  I have the lower gear doors with rotated brake calipers for what it is worth.

 

How much impact does this have on airspeed? I should have taken pictures but the gaps are not huge, and 1/8 or so in the front, but are twice that in the back.

[Bryan]

My M20K doors are tight. In fact, maybe too tight. I am picking it up from annual tomorrow and one of my squawks was the lower door rubbing on the main door when gear is down and full weight is on the wheels.. I think my MSC resolved that with re-rigging.  The doors should be flush, I am almost positive.

 

[ArtVandelay]

I had this problem, was a fairly easy fix, my nose gear doors weren’t closing completely either.


Tom

[Andy95W]

Optimally, yes, they should just barely touch the underside of the wing.  But I definitely would not worry about a 1/8" gap.  High pressure on the underside of the wing will likely push the gear and doors further into the wing while in flight.

If you and the shop have the time, they can probably get them adjusted in 1 hours' labor.  If your airplane is done, I would wait until next year, IMHO.

[Guest]

As Andy says, ideally the doors should make light contact with the skins and each other.  I would add that a layer of chafe tape to protect the skins is important.

Clarence

[bradp]

Anyone have a good source for chafe tape?  Could use a roll.  Lent one out and never saw it again. Last time I got one I was 1) surprised how much it cost and 2) was intrigued that it's used on an industrial scale for conveyor belts.

[DonMuncy]

Aircraft Spuce?

[PT20J]

This is a lot less expensive than the 3M UHMW tape that Mooney specifies. I bought some to try but haven’t tried it yet. 

https://www.amazon.com/gp/aw/d/B00823JBVG?psc=1&ref=ppx_pop_mob_b_pd_title

Maintence Manual has procedure for adjusting gear doors flush. 

[jetdriven]

there is a UHMW teflon anti-chafe tape from McMaster-carr its very good.

[milotron]

14 hours ago, M20Doc said:

As Andy says, ideally the doors should make light contact with the skins and each other.  I would add that a layer of chafe tape to protect the skins is important.

Clarence

Hi, the doors all have chafe tape and are clearly not making contact at the back. I'll spend some time with them at the shop at the next annual and get them tuned to my liking. Gotta be worth a knot or two!

[jetdriven]

I would not worry about the doors not making contact at the rear. Sometimes the gear cannot retract enough to pull the gear doors in tight enough even with no spacers between the landing gear standoffs and the door. But however the front gap I s a serious problem because it Rams air into the gap. If you have the Lasar manufactured modworks doors, those things are so flimsy actually curve and peel off of the wings.  I reinforced mine  wirh carbon fiber to rectify this.  Then I threw in the towel and made molds and reproduced them in carbon fiber and sold those to another guy. His is working great but I have recessed  bolt holes. 

Edited February 2, 2019 by jetdriven

[milotron]

25 minutes ago, jetdriven said:

I would not worry about the doors not making contact at the rear. Sometimes the gear cannot retract enough to pull the gear doors in tight enough even with no spacers between the landing gear standoffs and the door. But however the front gap I s a serious problem because it Rams air into the gap. If you have the Lasar manufactured modworks doors, those things are so flimsy actually curve and peel off of the wings.  I reinforced mine  wirh carbon fiber to rectify this.  Then I threw in the towel and made molds and reproduced them in carbon fiber and sold those to another guy. His is working great but I have recessed  bolt holes. 

I do believe I have the modworks doors. I think they had been damaged in the past and a return was added on the bottom edge. They actually seem to be quite stiff.

[DaV8or]

On 2/1/2019 at 1:50 PM, jetdriven said:

there is a UHMW teflon anti-chafe tape from McMaster-carr its very good.

Which one? I checked out what they have, but which one do you use? It looks like they don't have clear, so those of us that don't have white planes might SOL I guess.

[jetdriven]

1 hour ago, DaV8or said:

Which one? I checked out what they have, but which one do you use? It looks like they don't have clear, so those of us that don't have white planes might SOL I guess.