Re: X-Air H Brake upgrade info
开云体育Just some notes here.
I found the drum brakes to be primitive and less than efficient. Mine failed when the shoes
kinked sideways and destroyed the drum, shoes and backing plate.? No parts were available at that time?
( blame Covid )
I wanted to upgrade using cable operation. I looked into hydraulic, but it involves a lot
to convert, and is considerably heavier and more expensive.?
I consulted with an engineer, and he stated that the forces on the brakes from a 120kg
cyclist trying to stop from 50 kmh, would be greater than slowing a 300 kg aircraft taxiing at 20kmh, or holding the aircraft at full throttle- the usual application of the brakes.
Perhaps in a severe emergency stop situation, the brakes may be near, at, or above their
failure load?
I'm not sure what the same situation would do to the drum brakes?
The mount supports the calipers as much as possible, with large mating surfaces, and? minimising
stress points. The rotational force is directed at the original lug on the axle? ( which the backing plate mated to ). High tensile bolts are used on caliper and disc mounting, using Loctite.
Overall, the pedal effort to hold or slow the aircraft feels about 30% less than the drums.
Braking is smoother, and more positive. The pads can be inspected or changed without removing
the wheels. The discs are also visible for inspection. Adjustment takes about 5 seconds to do. Replacement parts are readily available and reasonably priced.?
The whole conversion cost me about $300 Aussie , and about 4 hours on the mill, plus 2
hours to fit.?
Cheers
Clive Cunningham K&M HD Motorcycles U2 5-9 Kingston Ave? Richmond? South Australia 5033?? Ph +61 8? 8234 1090? kmmotor@... kmmotorcycles.com.au
From: [email protected] <[email protected]> on behalf of Michael Coates <mcoates@...>
Sent: Tuesday, 13 December 2022 7:31 AM To: [email protected] <[email protected]> Subject: Re: [XAIR] X-Air H Brake upgrade info ?
Hello everyone, the problem with using bicycle parts is they are simply not made to stop the weight of an aircraft. The calipers are just not strong enough and will eventually fail the first time you really need them, usually breaking off where they mount.
Bicycle braking systems are normally designed to pull up something that is a maximum weight of 120 kg total. Braking something 3 or 4 times this weight is much more than what the system is designed for, the rotor will build up so much heat that it will warp and the fittings holding the brake caliper will eventually break. You should be looking at systems for things like motor scooters. Even though the weight of a motor scooter is not as much as an aircraft they are continuously braking from fairly high speeds and are more than strong enough for something like the X-Air. You will see that the brake caliper itself is probably twice the weight because it has a decent casting where it attaches to the frame and also the disk itself will be 3 times thicker. Experience shows that the bicycle system especially if you go hydraulic works really well for things like engine run up at the first time you need to brake in a real emergency may end up in tears. Robert Marietta wrote on 13/12/2022 12:05 am:
Can you give us the?Shimano model or part number you used. -- With regards, Michael Coates AU +61 7 5522 0583 USA +1 213 984 1237 PIPISTREL AIRCRAFT DEALER OF THE YEAR 2012 Winner of the EAA August Raspet Award 2012 PIPISTREL AIRCRAFT DEALER OF THE YEAR 2017 mailto:mcoates@... skype name: xcomavionics Please note: because of the volume of e-mail we are now receiving our replies are done using voice recognition software in an effort to speed up the reply process. Sometimes the voice recognition program inserts silly words or doesn't actually do what it is meant to do. Occasionally these mistakes get through our quick proofreading of each e-mail sent, so please accept my apologies if the odd mistake gets through. Legal Notice: The information contained in this email is confidential and intended only to be read by the person(s) to whom it is addressed. No one is authorized to copy, use, disclose, distribute or rely on this information for any purpose whatsoever. If this communication has been sent to you in error, please email the sender and delete the message. "Amateurs practice till they get it right; Professionals practice till they can’t get it wrong." |
Clive Cunningham