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Do brakes drip during aerobatics?

A

Alan Erickson

Active Member
How much do the brake cylinder drip during typical zero- or negative-G maneuvers? Have you done anything about it? I have MC-5's on my 8A, and if you tell me that' I'll get messy brake fluid on my carpet and paint, I'll try to find a solution or build little check valves. Thanks for your help!
 
You need a RESERVOIR DOG!!! It's a little brass male/female fitting (1/8" NPT both) that seals the opening when negative and breathes when positive. Made by Alex Peterson.

20021105_reservoir_dog.jpg


I'm not financially offiliated with him. I bought one for my RV-7 and I've never, ever seen so much as a drop come out of the reservoir. That said, I don't do negative G stuff, so I'm probably not a reliable test subject...but I do think the design works.

I believe Alex participates in the VAF Forums and is probably watching...Alex you out there?
 
dan said:
You need a RESERVOIR DOG!!!
Click to expand...
Thanks, Dan! Of course, I just finished mounting up my MC-5 cylinders, so this won't work exactly - I'll hope that Alex has something similar for 10-24 threads...or switch brake cyls back to something Van-like.

Still would like to hear about upside-down folks' experiences! - though it does appear that this will be of concern to me, since Alex saw fit to make the above part.
 
When I used to do more negative stuff in my -6 I originally had some fluid puke out of the reservoir, but I too ended up with one of Alex's little widgets and now haven't seen a drop....but I don't do too much negative stuff anymore either. I have full inverted fuel/oil on my plane, but upside down just isn't much fun in the -6 for any extended time (seatbelt and seat geometry just suck in these planes and I tired of banging my head against the canopy)....

Cheers,
Stein

RV6's, Minneapolis
 
Dan, I am out there! See:

http://www.home.earthlink.net/~reservoir_dog/

for details.

Alan, I do not have a solution for 10-32 threads. I scanned the McMaster catalog and did not find a bushing. It likely exists, but I'm not sure where to find one. How do 10-32 straight threads seal, with an O-ring? I know of some fittings called "instant tube" which use 10-32, but I do not know the mechanism of sealing.
 
Alex, the MC-5's have a 10-24 straight-thread vent cap -- a nylon socket cap screw with a small hole drilled through the shaflt -- and no special sealing mechanism (though one could certainly add a noncaptive o-ring).

I think I'll just solve the problem more easily: this morning, I converted back to the standard Van's cylinders, and will just order two reservoirs from Spruce and two 'dogs from you. After she's up in the air, somebody'll get a good deal on the MC-5's.

Thanks, everyone!
 
The F1 that I built does a lot of negative "G" and no fluid spills. I used a PVC valve threaded into the top of the brake resevor it allows the tank to breath while right side up and the valve closes while inverted.
 
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