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Hole through FS-22


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As the photo below shows, someone has drilled through the FS-22 bulkhead in order to run lines through. Is this acceptable...

Hell, no. That area of F-22 is where the load from the canard attach tab bolts is fed through to the fuselage sides. One can imagine the result of a failure in that area. Holes in structure cause stress concentrations that can be on the order of 3X the stress in the surrounding structure.

, and if not how could it be repaired?

Well, there are a LOT of structural layups in F-22, including the doubler and the fuselage attach layups, all of which now have a hole through them. I don't think it can be repaired without tearing out all of F-22 and replacing it. That's the conservative route.

 

Given the hole's proximity to the lift tab attach bushing, I can't imagine how one would add reinforcing layups to the area that didn't create as much stress concentrations as the hole you're trying to fix.

 

People certainly do some stupid stuff. This is essentially like drilling a big hole through your spar cap.

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(I am leaning toward acceptable )

 

Me too, But I wouldn't recommend anyone else do this.

 

Fortunantly, the hole is toward the center where stresses are the least.

 

If you do repair,

 

You need to scratch (sand) F22 and the fuselage about 2 inches, Both front and back to get a good mechanical bond

 

Fill in the hole with flox.

 

Lay up 5 or 6 layers of BID on the back of F22 onto the fuselage. Lay up 2 layers in the front. Knife trim the BID around the area on the Front of F22 where the Canard tab touches.

 

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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If it was my plane, I would cut the nose off and remove & replace the entire bulkhead (and reroute the offending cable.)

 

But that's just me.

I would not be able to sleep with a defect such as that. It would gnaw on me until I got around to replacing it.

 

Just be glad it's a glass airplane which will allow you to make such a choice. Look on the bright side ....... it's a great opportunity to change the profile of the nose. :cool2:

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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Fill in the hole with flox.

 

Lay up 5 or 6 layers of BID on the back of F22 onto the fuselage. Lay up 2 layers in the front. Knife trim the BID around the area on the Front of F22 where the Canard tab touches.

I would in no way consider this to be an acceptable repair of this area, especially without any indication of the ply drops or orientation for any of the specified plies.
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G'Day Richard,

 

I purchased a partially complete project and whilst there were no structural issues with the F22, it was padded at one of the canard attach points. Whilst this was structurally sound, I decided to re-fabricate the F22 as I didn't want that sort of structure as a permanent part of my final aircraft.

 

F22 does take a bit of work (many lay-ups), and yes that foam is expensive (especially in Oz as a small order), but I do believe that you could carefully cut the F22 away whilst retaining the nose structure. To that point, perhaps even 'release' the NG30s from F22 at the same time (Marc, you may want to comment on the soundness of re-taping the existing NG30s back onto the new F22).

 

I hope this helps Rich', and I am certainly open to being corrected on this approach.

 

Cheers,

 

Bruce.

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... whilst there were no structural issues with the F22, it was padded at one of the canard attach points. Whilst this was structurally sound, I decided to re-fabricate the F22 ...

As you say, this was structurally sound, and there was no reason at all for you to redo F-22. Padding the attach point is a plans approved method (with layers of glass) of ensuring that the canard is square. There is no assurance that refabricating F-22 will keep you from having to pad one of the attach points again, when aligning the canard - F-22 has a 3.5 ft span, while the canard is a 12 foot span. Any misalignment, however small, of F-22 will be magnified by a factor of almost 4 when doing the installation. Hence the need for a little padding on occasion.

 

... (Marc, you may want to comment on the soundness of re-taping the existing NG30s back onto the new F22).

Pretty trivial - sand off the previous attach layups and do them over. It's just 2 BID all around.
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As the photo below shows, someone has drilled through the FS-22 bulkhead in order to run lines through. Is this acceptable, and if not how could it be repaired?

 

(I am leaning toward acceptable :( )

 

 

[ATTACH]2800[/ATTACH]

thats a sticky one, i would(mine, not yours) look at the attach layers to see they were 110%, then lay up 2 bid over the hole and over the tab so the tab would be covering the new lay-up and 2-3" over the side of fuz.

BUT all bets are off if i could not clean the hole area.i dont like going over crappy bid tapes.

ps. you would need to pad the canard to fit when done.

as marc is a little over the top and im a little under, you have to fly it like tman said. its not my butt on the line.

i have 10 things on my bird i dont like and at some point i said "this will do"

even now as i type i still worry about them.......so keep track of the "O well's"

and add them to your pre-flight check list.;)

Steve M. Parkins

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i have 10 things on my bird i dont like and at some point i said "this will do"

even now as i type i still worry about them.......;)

Not me. I don't let that stuff eat at me. I found that it takes less time overall to go back and address the issue. I don't need another thing to think about.

 

You minimize the risks as much as you can then you go.

 

Have you minimized the risks?

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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That is some ugly-looking workmanship but I would repair it something like Waiter has suggested.

 

I'd use a right-angle die grinder with a coarse abrasive disk and clean up the whole area. Go slowly and you can sand away most of the BID reinforcements that lap from F22 to the sides, until you are just seeing the base layers on F22. Fill the hole with flox and replace the reinforcements per the plans plus maybe a couple more for momma. It'll be fine

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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Not me. I don't let that stuff eat at me. I found that it takes less time overall to go back and address the issue. I don't need another thing to think about.

 

You minimize the risks as much as you can then you go.

 

Have you minimized the risks?

not yet but i will.

Steve M. Parkins

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Thanks very much to all for the quick replies. :thumbsup:

Its amazing the trouble a little 3/8" hole can cause. I must have looked at it a hundred times over the past year without noticing it.

The E-racer layup schedule for this area is a little different than the cozy or long-eze:

 

Front face of FS-22 - 2 ply BID overall, 6 BID and 6 UNI alternating in the tab area top to bottom

 

Aft side - 2 BID overall, Doubler, 4 BID overall

 

After fuse assembly - 4 BID lapping over the fuse side and the aft face of FS-22 in the tab area

 

My current plan is to sand off the zolatone and the top layer of fiberglass front and back, plug the hole with flox and then duplicate the original layups.

(might have to do the other side to keep it even)

There is really no room to taper 1" per ply as chapter 3 suggests.

This should only move the canard forward about 0.125 in., which I think I can get away with. I will also have to remove the canard bolt bushings and replace them after the repair.

 

The CP issue dealing with load testing the canard reported that the canard was loaded with 3500 lbs of sand before it failed at 12 G's. Thats 1750 lbs at each bolt!

"We choose to do these things not because they are easy, but because they are hard."

JFK

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