Intake rubber accordion boot

[MikeOH]

Second @Ragsf15e experience; I get 2-3 knots when I open the ram air on my 1970 F model.  No idea why anyone would 'block it off'???  The air at cruise altitude is just not that dirty!

[varlajo]

25 minutes ago, MikeOH said:

Second @Ragsf15e experience; I get 2-3 knots when I open the ram air on my 1970 F model.  No idea why anyone would 'block it off'???  The air at cruise altitude is just not that dirty!

Yeah, same here, although I am paying with a 0.4 gph ff increase for those 2-3 knots.

Essentially, a torn boot in an E/F is an equivalent of a permanently not-quite-fully-open, not-quite-ram air, plus the obvious consequences of rubber chunks entering the induction system. 

Edited June 9 by varlajo

[Ragsf15e]

37 minutes ago, varlajo said:

Yeah, same here, although I am paying with a 0.4 gph ff increase for those 2-3 knots.

Essentially, a torn boot in an E/F is an equivalent of a permanently not-quite-fully-open, not-quite-ram air, plus the obvious consequences of rubber chunks entering the induction system. 

The real bad failure comes if they get so bad that they compress in and block air altogether or ingest a piece big enough to block air.  There’s pictures around here somewhere of one that was duct taped many times and who knows how old.  It closed itself off and the engine quit.  It’s not a part you want to fail catastrophically (and that’s definitely rare).

[H Foster]

Just following up on this.  I found a guy locally that was parting out an M20C that had a serviceable duct.  It had a couple of small holes but fixed it with some RTV and installed.  I still have a new on on order from Lasar.  It costs $670 each and they need 50% deposit.

[pirate]

Ordered my intake boot (C model ) from Lasar last January and just received it. Pretty much 6 months to the date. 

[hoot777]

What do you guys use to fasten the accordion piece to the air box ??  A tie rap .??

[varlajo]

1 hour ago, hoot777 said:

What do you guys use to fasten the accordion piece to the air box ??  A tie rap .??

A lot of choice words, mostly.. 

[cliffy]

2 hours ago, hoot777 said:

What do you guys use to fasten the accordion piece to the air box ??  A tie rap .??

Parts manual available on line here

[47U]

2 hours ago, hoot777 said:

What do you guys use to fasten the accordion piece to the air box ??  A tie rap .??

I forget where I found this clamp, but Wraplock would work well, or chain together a couple of long worm gear hose clamps.  I think the blue-line drawing that came with my carb heat/dump valve overhaul kit spec’d the Wraplock.

https://www.efc-intl.com/viewitems/screw-drive-clamps/wraplock--shape-conforming-drive-clamps

[Gee Bee Aeroproducts]

Don't use mineral spirits to clean 

 

The boots are made on a mandrel 

 

Tye best solution is a two piece mold 

silicone with nomex cloth layer 

GB

Note 

my black sceet ducts are a little long with two inches of cuff, trim to your fitment.

I have some inventory that I will offer as we're moving location.

The defrost ducts are always stock

2.5 x 14

2.5 x 24

 

 

[N201MKTurbo]

That duct is made with a support for the wire at the corners. It is a single length of rubber coated steel wire that is spiral wrapped around the curved corner supports. The corner supports are in a position that has the cotton reinforced rubber sheet stretched out. It is a single sheet of rubber with about a 2” overlap on the bottom. After the rubber is stretched over the wire, the fixture that holds the wire supports apart is removed and a rubber coated cotton string is spiral wrapped in between the wires to create the accordion shape. The ends appear to be clamped to a mandrel when the assembly is vulcanized.

I got all this by disassembling a worn out boot.

[Gee Bee Aeroproducts]

Not the way I would mfg as I don't like Epdm rubber .

The vendors won't change the print and either will mooney .

Low volume, high cost .

GB

[MikeOH]

4 minutes ago, Gee Bee Aeroproducts said:

I don't like Epdm rubber .

Why?

[N201MKTurbo]

1 hour ago, Gee Bee Aeroproducts said:

Not the way I would mfg as I don't like Epdm rubber .

The vendors won't change the print and either will mooney .

Low volume, high cost .

GB

Once every year or two, Aeroduct will pull that old fixture off the shelf, get out the old work instructions. Scratch their head for a bit and make a few.

[Gee Bee Aeroproducts]

Silicone with nomex 3ply we mold has a lifetime warranty.

i sell 300/500 per year 

The drain is molded into the ply

with or without drain assy

 

i rather do inflation or static door seals for pressurized aircraft.

When there is oil or fuel contamination it's best to use ams3325 Flurosilicone liner.