Installing firesleeve

LettersFromFlyoverCountry · #1 11-29-2010, 06:58 AM

I've watched the very excellent EAA video on installing firesleeve, but I still have one question that was unanswered. I've installed a couple of right-ange Aeroquip fittings on an Aeroquip 701 hose used for a fuel line. It's clear to me on a straight fitting, the firesleeve should go right to the nut, but I have a hose with a couple of right angle fittings. Should the firesleeve end at the hose-to-fitting connection? Or should it go onto the much smaller tubing that forms the right angle?

cfiidon · #2 11-29-2010, 09:15 AM

I'm no expert but here's my opinion:

I used steel fittings on all fuel and oil lines firewall forward. With that approach, all you need to worry about is that the firesleeve covers the hose.

Yours appear to be aluminum. I'd cover it.... or change to steel.

Don

foka4 · #3 11-29-2010, 01:59 PM

I wondered the same thing, and researched what others have done. Here are the most popular solutions I found in my non-scientific study:

1) terminate the fire sleeve before the elbow and leave the aluminum elbow exposed. Not the greatest solution in the world, but keep in mind you're attaching the hose to an aluminum gascolator, an aluminum fuel pump, or an aluminum carburetor in most cases. The fire sleeve still protects the rubber.

2) order a steel 90 degree fitting from Aircraft Spruce. Part number 04-05800. This option eliminates the aluminum elbow and the hefty price tag that goes with it. This fitting does add another threaded connection in the system, though.

3) use some other series of flex hose for the fuel lines. I'm not aware of steel end fittings for Aeroquip 701 hose.

I went with option 2. Let us know what you decide to do!

M

TS Flightlines · #4 11-29-2010, 02:21 PM

Put your firesleeve up to the nut that screws into the collar over the hose. You want to protect the liner of the hose. You can seal the firesleeve end with red RTV, or end dip (expensive-look on here for alternatives). No point in firesleeving if a flame could get to the hose liner. Also, for whats its worth, that's why I use stainless hose ends.
Tom

LettersFromFlyoverCountry · #5 11-29-2010, 02:47 PM

Quote:

Originally Posted by TS Flightlines

that's why I use stainless hose ends.
Tom

Sigh. I'm beginning to wonder if I should even bother finishing this project. At this stage it seems like I'm spending hundreds of dollars for stuff only to find out I need to spend hundreds more for something better.

It'd be a lot easier if I had hundreds of dollars.

Brantel · #6 11-29-2010, 02:55 PM

Bob,

Good enough is good enough....

Put the sleeve up to where the elbow screws into the hose. That is how all the factory ones are made.

Thousands of these in use today on certified birds. Move on....don't spend more!

LettersFromFlyoverCountry · #7 11-29-2010, 03:00 PM

This is one of those areas where it's impossible to get actual data. Is there a significant safety difference between steel and aluminum fittings? Or is it more "this could happen or that could happen" fear that's driving the issue? If there is a definitive safety margin, what is it? Is it greater than, say, not properly securing a line? Is it a difference along the lines of the difference in safety between putting one of those (overpriced) stainless steel heat deflectors on an exhaust pipe under a fuel line and not putting one on.

Very, very difficult to make educated decisions based on actual calculations and testing. At least for me.

Ironflight · #8 11-29-2010, 03:50 PM

Here's a suggestion that might help Bob. Next nice day at the airport, go wandering around to open hangars to see if anyone has their cowl off of their certified airplane. Poke around - see what the industry does, what has been CERTIFIED by the FAA. It will make you feel alot better.

You're right - many builders without a lot of aircraft maintenance (or design) background simply don't know the difference between "good", "good enough", and "perfect". Don't be a non-finisher because you're afraid to say it is "good enough".

Paul

foka4 · #9 11-29-2010, 03:54 PM

Bob,

Many of us share your frustration. Although I know we are building experimental aircraft, I'd expect with so many RVs flying, a number of these details would be well sorted by now. Unfortunately, much is still left to the individual builder, and as importantly, the DAR who will sign off your project.

Opinions vary widely on many seemingly trivial details, but such is the nature of any pursuit of this complexity.

The forum has been a tremendously valuable resource, but at times it's almost a curse, since there is so much information and so many opinions on any topic. Often, it's best to do a quick search to see your options, choose one that you think will work, and ask your A&P/DAR if it's okay. Beyond that, it's pretty easy to get endlessly bogged down in weighing uncertain options with incomplete information.

With regard to fuel hoses and such, certified aircraft are often a good guide. A trip to the local airport for a peek under the hood of a 172 or Cherokee can work wonders.

If you think fuel hoses are a vague, varied, and contentious topic, just wait until you start figuring out what to do about running the primer lines. Oh, and speaking of primer...

Good luck, and best wishes. Hope your frustration is short lived. In the end, having a flying RV will make you quickly forget the bumps in the road.

M

FredMagare · #10 11-29-2010, 04:01 PM

Quote:

Originally Posted by Bob Collins

This is one of those areas where it's impossible to get actual data. Is there a significant safety difference between steel and aluminum fittings? Or is it more "this could happen or that could happen" fear that's driving the issue? If there is a definitive safety margin, what is it? Is it greater than, say, not properly securing a line? Is it a difference along the lines of the difference in safety between putting one of those (overpriced) stainless steel heat deflectors on an exhaust pipe under a fuel line and not putting one on.

Very, very difficult to make educated decisions based on actual calculations and testing. At least for me.

I don't have the answer to your question, Bob, but it seems like it's kind of like buying any type of insurance - if you never need it, it's wasted money but if you NEED it, I'll bet you'll be glad you've got it! If you never suffer a fire because of aluminum fittings - no harm, no foul but would you wish you'd have spent the money on steel if a broken fitting causes a fire in flight?

It's a tough call. Were I in your position, I'd likely install the aluminum-fitted hoses with the intent to change them to steel at a predetermined "No Later Than" date...say three to five years? Some hose use might ease the sting of "unused".