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Backcountry Pilot • Flap gap seal removal

Flap gap seal removal

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Flap gap seal removal

These flap gap seals came with the bird. I’ve read they dramatically reduce STOL. That’s the last thing I want especially for a couple MPH in cruise.

From what I’ve read there are hard ways and easy ways to remove them.

The obvious way I would guess would be to drill out the rivets and re-rivet. Timely process and not ideal for paint.

I’ve also heard you can just score the back and pop it off? Has anyone done that?

Thanks
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Lettucelord offline
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Re: Flap gap seal removal

I removed the flap gap seals on my 53 years ago by drilling out the (many, many!) cherry-max rivets.
(there's a procedure for that- you grind off the steel collar before drilling)
The airplane had been painted after the seals were installed,
as this left a slightly different colored strip under where the seals had been.
Plus all the rivet holes.
This was before I'd heard of scoring, then snapping off the seals.
I'd give that a try first.
hotrod180 offline
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Re: Flap gap seal removal

I am still rocking the flap gaps! Loving my speed increase!
C180_guy offline
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Re: Flap gap seal removal

Honestly, unless you’re competing and a very skilled STOL pilot, I’d leave it alone, just don’t think the juice is going to be worth the squeeze

But if you’re very skilled at STOL and are competing, I get it

Ether way, good looking plane, like the red
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Re: Flap gap seal removal

NineThreeKilo wrote:Honestly, unless you’re competing and a very skilled STOL pilot, I’d leave it alone, just don’t think the juice is going to be worth the squeeze

But if you’re very skilled at STOL and are competing, I get it

Ether way, good looking plane, like the red

^^^^ This.
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Re: Flap gap seal removal

Definitely not competing but do seasonal Idaho back country trips with heavy loads into the shorter strips so I feel I should do my best to improve margins where I can.
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Re: Flap gap seal removal

For the sake of full disclosure, I have to say I didn't see a big change in low speed / flaps down handling or performance.
So while I'm not unhappy I removed them, I dunno if I'd go to the trouble again.
Last edited by hotrod180 on Thu Mar 28, 2024 8:17 am, edited 1 time in total.
hotrod180 offline
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Re: Flap gap seal removal

hotrod180 wrote:For the sake of full disclosure, I have to say I didn't see a big change in low speed / flaps down handling.
So while I'm not unhappy I removed them, I dunno if I'd go to the trouble again.


From what I’ve heard it’s mostly a takeoff performance reduction rather than landing? Not sure how true that is.
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Re: Flap gap seal removal

NineThreeKilo wrote:Honestly, unless you’re competing and a very skilled STOL pilot...


-1

The flap gap seals destroy what the fowler flap was meant to do. If you want speed, buy a Cirrus, otherwise they should be removed to let the wing do what it was designed to do... and yes, there is a difference (if one chooses to fly as slow as one can fly the bird)

Do as you suggested. Drill out only the handful of rivets at the ends, then score the alum just aft of the trailing edge of the factory skin and snap, then Bob's your uncle.
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Re: Flap gap seal removal

Bigrenna wrote:
NineThreeKilo wrote:Honestly, unless you’re competing and a very skilled STOL pilot...


-1

The flap gap seals destroy what the fowler flap was meant to do. If you want speed, buy a Cirrus, otherwise they should be removed to let the wing do what it was designed to do... and yes, there is a difference (if one chooses to fly as slow as one can fly the bird)

Do as you suggested. Drill out only the handful of rivets at the ends, then score the alum just aft of the trailing edge of the factory skin and snap, then Bob's your uncle.

Ah, used to be 'if you want speed, buy a bonanza.' at least you updated that old tired saying. The beauty of 180s is they are a decent cross-country plane and a decent backcountry plane. I will update your tired expression by saying 'if you want a super STOL plane buy a Carbon Cub.'
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Re: Flap gap seal removal

It’s all about your mission. I have flap gap seals on a 185F and can still get her stopped in 1/2 my takeoff distance . So stol performance isn’t really the issue. Where I think it can be somewhat nuanced is that it seems like there is a different feel with and without the seals. For instance, about every 1 in 250 landings, I feel like the ass drops out of the plane at slow speed. It’s when you might have slightly missed your spot, usually on a bigger runway, when you’re tired, flown too much,etc. and it will drop you for a minor skill infraction. Maybe it is this way on all wagons but my theory is that it might have something to do with the flap gap seals, slow speeds, and the comparable less lift at flaps 40. No big deal when you’re on your game and working short strips but this creeps up on you if you’re a little complacent. I’ve had 2 embarrassing bounces which probably could be attributed to the seals making the plane a little less forgiving… or I’m just looking for reputable excuses…

Remember this is just theory but the physics make sense in my head. If you fly final at 70+mph, you probably won’t run into this.
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Re: Flap gap seal removal

Bigrenna wrote:
NineThreeKilo wrote:Honestly, unless you’re competing and a very skilled STOL pilot...


-1

The flap gap seals destroy what the fowler flap was meant to do. If you want speed, buy a Cirrus, otherwise they should be removed to let the wing do what it was designed to do... and yes, there is a difference (if one chooses to fly as slow as one can fly the bird)


I know you're a man of strong opinions, but this is just wildly overstating things. I've been everywhere in Idaho and many places in Alaska heavy and can land and take off plenty short enough. As I've said many times on here, I wouldn't necessarily tell someone to *add* gap seals, but any negative effect has to be extremely marginal for anyone not trying to win a STOL competition. There's on the other hand a decent argument that it helps flaps-up climb, which can be helpful in the backcountry.
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