Couple questions. 1. Why not use the flexible hosing in the entire aircraft for ease of installation, plus stronger than nylon? 2. Would it not be of the upmost importance to run the lines in such a way as to protect them from any possible snagging that may occur from, grass, rocks, or birds? For example: running them aft along the struts to protect from forward damage, not under or in front. Or Running them inside the aircraft as soon as possible vs running them under the aircraft? Does anyone have experience in trying to mitigate the potential issues that may arise with poor placement?
Excellent tip, as usual. Also, I would like to see your take on flaring tubing . . . it HAS to be better than mine. Also, does your plane leave the lines exposed on the belly? Seems a prime candidate for damage.
John, when you came off of the landing gear strut and turned to go under the floor of the aircraft through the tunnel how did you put in the 90 fittings through the floorboard?
At 10:10 (and elsewhere), you can see significant scratches in the aluminum tubing. I would think that those would be a good starting point for fatigue cracking in your brake line. Comments?
I don't think I'd be concerned about superficial marks like that unless there was significant vibration or flexure at that point that might tend to develop the cracks. I'd think it would take a very long time for these to develop into anything serious just by hydraulic pressure in the line, especially considering how little brakes get used during flight. What worries me a bit more is that possibility of damage to the lines where they go unprotected down the struts, where they might get hit by tall grass or small stones or the like.Of course, you are supposed to check all this stuff visually before flight. But does everyone do that?
"Typical" brake lines on autos use 45 degree DOUBLE flares (a different type of flare) ; our aircraft use AN single flare 37 degree (autos can also use these on other non-brake hydraulic applications) They are NOT compatible - do NOT mix 45 an 37 degree flare connections!
The 2 are not compatible. Aviation is 37 deg where as automotive is 45 deg. If you purchase prefabricated flex lines or a flaring tool make sure they are 37 deg. before you buy it. All of your AN fittings like shown using the -3 or bulkhead fittings. The nipple end is a 37 degree.
I wouldn't have thought it even possible to build an hydraulic brake system using nylon or any other type of plastic tubing. The whole point of hydraulics is that one is pumping an incompressible fluid, but having tubing that can expand under pressure defeats the purpose.
I have good news for you. These aircraft brake systems operate at much lower pressures then what you're assuming. It's not like an automotive system. To give context, The maximum working pressure for the nylon is 600 PSI. Versatube 3003 is rated at a maximum working pressure of 880 PSI for 3/16". There is no concern of the nylon expanding. It simply isn't a problem at the low pressures the system operates at and it's standard to use nylon.
@@Bottleworksnet And what about temperature ? when breaking from high speed for longer time, breaks get heat up pretty quickly and the end of the tube connected to the cylinder body could melt and start leaking
@@trhacje_m2187 They don't get anywhere that hot. Not even what I would consider warm. I hope you understand that these brake systems were designed for use with the plastic lines by aerospace engineers. THEY DID THE MATH (AND TESTS)!!! Thousands of aircraft fly with these plastic lines.
Thanks for all your videos! I've learned so much!
The braided stainless steel hose has nylon tubing inside. The 1/8" nylon tubing is good and can be sleeved with 1/4" nylon tube for protection.
This is a big help, right when I need it. Thanks!
You are amazing teacher.
Couple questions.
1. Why not use the flexible hosing in the entire aircraft for ease of installation, plus stronger than nylon?
2. Would it not be of the upmost importance to run the lines in such a way as to protect them from any possible snagging that may occur from, grass, rocks, or birds? For example: running them aft along the struts to protect from forward damage, not under or in front. Or Running them inside the aircraft as soon as possible vs running them under the aircraft? Does anyone have experience in trying to mitigate the potential issues that may arise with poor placement?
Excellent video!
Excellent tip, as usual. Also, I would like to see your take on flaring tubing . . . it HAS to be better than mine. Also, does your plane leave the lines exposed on the belly? Seems a prime candidate for damage.
I would like a future tip to cover flaring techniques please!
It has been done! The next Tip here: czcams.com/video/RyG2Slbaz2Y/video.html
John, when you came off of the landing gear strut and turned to go under the floor of the aircraft through the tunnel how did you put in the 90 fittings through the floorboard?
At 10:10 (and elsewhere), you can see significant scratches in the aluminum tubing. I would think that those would be a good starting point for fatigue cracking in your brake line. Comments?
I don't think I'd be concerned about superficial marks like that unless there was significant vibration or flexure at that point that might tend to develop the cracks. I'd think it would take a very long time for these to develop into anything serious just by hydraulic pressure in the line, especially considering how little brakes get used during flight.
What worries me a bit more is that possibility of damage to the lines where they go unprotected down the struts, where they might get hit by tall grass or small stones or the like.Of course, you are supposed to check all this stuff visually before flight. But does everyone do that?
How do the breaks work and are there different types?
Just one question John. I thought automotive flared fittings had a 45 deg flare instead of the aviation 37 deg flare. Are the two compatible?
"Typical" brake lines on autos use 45 degree DOUBLE flares (a different type of flare) ; our aircraft use AN single flare 37 degree (autos can also use these on other non-brake hydraulic applications) They are NOT compatible - do NOT mix 45 an 37 degree flare connections!
The 2 are not compatible. Aviation is 37 deg where as automotive is 45 deg. If you purchase prefabricated flex lines or a flaring tool make sure they are 37 deg. before you buy it. All of your AN fittings like shown using the -3 or bulkhead fittings. The nipple end is a 37 degree.
What's the aircraft type in the video?
What about stand offs?
I wouldn't have thought it even possible to build an hydraulic brake system using nylon or any other type of plastic tubing. The whole point of hydraulics is that one is pumping an incompressible fluid, but having tubing that can expand under pressure defeats the purpose.
What makes you think the nylon line expands in a typical installation?
+Turning Short Final - The modulus of elasticity of nylon is much, much lower than that of aluminum or steel, that's why.
I have good news for you. These aircraft brake systems operate at much lower pressures then what you're assuming. It's not like an automotive system. To give context, The maximum working pressure for the nylon is 600 PSI. Versatube 3003 is rated at a maximum working pressure of 880 PSI for 3/16". There is no concern of the nylon expanding. It simply isn't a problem at the low pressures the system operates at and it's standard to use nylon.
@@Bottleworksnet And what about temperature ? when breaking from high speed for longer time, breaks get heat up pretty quickly and the end of the tube connected to the cylinder body could melt and start leaking
@@trhacje_m2187 They don't get anywhere that hot. Not even what I would consider warm. I hope you understand that these brake systems were designed for use with the plastic lines by aerospace engineers. THEY DID THE MATH (AND TESTS)!!! Thousands of aircraft fly with these plastic lines.