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jon
09-24-2004, 02:54 PM
Has anyone used these brake lines? Looking in a motorcycle
parts book for Harleys, they sell stainless braid line with teflon lining
and installed AN3 fittings. They can be ordered in 2" increments ,
have a higher oper. PSI than 303 hose and 1/2 the cost. I like
supercub MD installation, run one line from master to wheel.

Building a Smith, Thanks John

Steve Pierce
09-24-2004, 03:46 PM
I have found grease gun lines in certified SCs. 3000 psi rating.

Cimarron
09-24-2004, 05:06 PM
Its amazing what people will put into aircraft not worrying about compatability or safety to save a few bucks.

mvivion
09-24-2004, 06:04 PM
Yeah, but Cimmaron, in this case, it's not about saving a few bucks, it's about using genuine Harley Davidson parts.

You obviously haven't bought Harley parts recently. I think they got their pricing structure from Cessna.

Sorry, couldn't resist.

MTV

Jerry Burr
09-24-2004, 06:30 PM
The braided lines have a lot of (give) compared to a metal line. If you don't have them tied down and are using boosters the line will just stand up by itself when pressure is applied. Other than that they (look) good. Jerry. :)

Cimarron
09-24-2004, 07:26 PM
next thing is a viagra mix in the booster cylinders

j3jm
09-24-2004, 08:12 PM
Talk about stiff brakes.

jon
09-24-2004, 09:16 PM
Cimarron, I agree with you. I am starting to see larger planes using
the plastic brake lines with compresion fittings :-? Im not sold on that.
The Harley lines made by Russell Brakes are the real thing. Russell
uses aerospace hose, stainless AN ends and whip tested to meet DOT
specs. They manufacture fluid lines for all transportatin industries but
aviation. The liability and small market is why they do not. I guess
being an experimental builder has me always look for better or new
ways of doing things .

John

CrossedControls
09-26-2004, 09:52 AM
Harley's have never ever had a reputation for good brakes.
The standard upgrade for fast machines is Goodridge hoses
I understand they have always used aircraft standard material, and you can get them in pretty colours too.

http://www.goodridge.net/

They do stuff for Formula 1 and NASCAR

Pete

Cub junkie
09-26-2004, 11:14 AM
Hard lines is the best way to go . Like Jerry Burr said if the braided type hoses are not secured they will move around on master cyl. application. The teflon lined braided hoses are better than the standard rubber/braided stainless. I have noticed many types of homebuilt aircraft use the teflon lines with brass fittings with apparently no troubles. All of the above just my 2 cents worth.

Cimarron
09-26-2004, 01:06 PM
Forget the plastic, they get hot around the brake and leak. solid lines where don't have movement is always the best. good aircraft hoses are not that expensive for the 6" pieces you will need at flex areas. At least you know the materials are compatable with the fluids. If you want to use DOT 3 fluid use automotive hose. If you plan on using 5606.....

S2D
09-26-2004, 06:20 PM
Lot of spray planes have at least 10 feet of flexible line and they have no problems. Compatibility would be most concern. Some old spray planes ran automotive fluid and mixing either way can be disasterous unless you like landing with the brakes locked. Material jon was talking about sounds exactly like what Cub Crafters sent with the Brake Booosters years ago. The bulk material from aviation supply houses isn't that expensive if you know how to fabricate your own.

Crash
09-26-2004, 10:07 PM
The ends for the stainless steel braided / teflon lines are really expensive. They also don't seem to catch much meat at the end of the hose. I used them inside the fuselage on the 14 but went standard Aeroquip 303 on the gear legs because I felt someone would slip with a foot and tear the hose out of the fitting. I've seen guys using braided stainless lines on gear legs as well. Crash

FixedWing
09-27-2004, 04:21 PM
The new DOT approved braided steel hoses have come about through a change in the DOT interpretations. Previously it was not possible to get these hoses DOT approved.

The problem is that certain compromises were necessary to get these hoses DOT approved. For example, the ends need to be permanently affixed. This usually means a crimped end. It cannot mean an end that can be loosened again. These are actually not as reliable.

Also, because of some of the rules for wrapping them, it can be difficult to impossible to inspect them properly.

For this reason, racers don't use these DOT lines and in fact, many who are running performance cars on the steet do not either.

I would think that the four issues with brake lines on a Supercub are 1) compatability with fluids, 2) expansion, 3) safety and 4) cost. Heat is probably not an issue on an airplane.

On all grounds, steel brake lines are superior. With cars, the reason that they use brake hoses is because the wheels steer and they cannot use solid steel. But on a good car, every bit of it is steel where it can be steel. It is just better.

Stephen