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#201
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How do you find the limits of areas on a chart?
"flyncatfish" wrote That's a good question. I think it's more like a truck brake. Snippage The Yak 52 has no parking brake, other than a latch on the stick handle for keeping the brake handle compressed. So if I understand correctly, you say if there is no air pressure there are no brakes? If that is the case, it is not like truck brakes. Truck brakes have a very heavy spring that keeps the brakes applied on full force, if there is no air. You can see why, so that if an air line or tank ruptures going down the road, you just stop. Right now! I did it once from a slow speed to see how good they grab. Very good is the answer! g You would have major flat spots if you did it from any great speed! How they work is by applying air to the back side of the air cylinder that operates the brake. That pulls the shoes away from the drum, against the "applying" action of the spring. When you want to stop, air is let into the side of the cylinder on the opposite side of the piston as the first supply I mentioned, and it pushes the shoe towards the drum, and at the same time, pushes some of that first air back into the air tank. Really, what you are doing is letting the spring apply the brake, by reducing the pressure differential from one side of the piston to the other. It sounds like you are worried if the air pressure drops too low from starting, and that would not be a problem with truck brakes. Also, holding the brake lever down for parking makes it sound like there is no applying spring, and air on one side of the piston, only. -- Jim in NC |
#202
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How do you find the limits of areas on a chart?
Top-posted 'cause I'm lazy!
For a truck you want the brakes to apply if the air system fails. For a plane, you want the brakes not applied if the air system fails. In the truck you want the brakes to apply full on if the brakes system air supply fails, it means you have to start the truck and wait for air pressure to build before moving the truck, but it makes or safe driving when the brake air fails on a big hill. If the brakes were to be applied at full strength by a spring while you were flying, then when you touch down, you will wind up on your nose or your back, and you will have to call the insurance company..... By having brakes that remain off if the air system fails, you can simply land on a longer runway which allows for the non-functional brakes. Yet another reason for having that emergency fuel in the tank, so you can divert when the warning light comes on. Or you can have a lower speed taxi accident, that as a pilot you should at least be able to kill the switches before hitting the expensive whatever. Battle of Britain pilots were warned that when a crash was going to happen, they were to crash into the softest, least expensive thing..... Although these air brakes don't make for a good long term parking brake, chocks will hold a plane in one place, and even if air has leaked from the tank, if the motor can be started and run until air is built up, the motor can then be stopped and restarted later to supply enough air for the short duration required if you alone have to remove the chocks while fuelling at the bowser. Hope this helps, Pete "Morgans" wrote in message ... "flyncatfish" wrote That's a good question. I think it's more like a truck brake. Snippage The Yak 52 has no parking brake, other than a latch on the stick handle for keeping the brake handle compressed. So if I understand correctly, you say if there is no air pressure there are no brakes? If that is the case, it is not like truck brakes. Truck brakes have a very heavy spring that keeps the brakes applied on full force, if there is no air. You can see why, so that if an air line or tank ruptures going down the road, you just stop. Right now! I did it once from a slow speed to see how good they grab. Very good is the answer! g You would have major flat spots if you did it from any great speed! How they work is by applying air to the back side of the air cylinder that operates the brake. That pulls the shoes away from the drum, against the "applying" action of the spring. When you want to stop, air is let into the side of the cylinder on the opposite side of the piston as the first supply I mentioned, and it pushes the shoe towards the drum, and at the same time, pushes some of that first air back into the air tank. Really, what you are doing is letting the spring apply the brake, by reducing the pressure differential from one side of the piston to the other. It sounds like you are worried if the air pressure drops too low from starting, and that would not be a problem with truck brakes. Also, holding the brake lever down for parking makes it sound like there is no applying spring, and air on one side of the piston, only. -- Jim in NC |
#203
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How do you find the limits of areas on a chart?
Morgans wrote: "flyncatfish" wrote That's a good question. I think it's more like a truck brake. Snippage The Yak 52 has no parking brake, other than a latch on the stick handle for keeping the brake handle compressed. So if I understand correctly, you say if there is no air pressure there are no brakes? If that is the case, it is not like truck brakes. Truck brakes have a very heavy spring that keeps the brakes applied on full force, if there is no air. You can see why, so that if an air line or tank ruptures going down the road, you just stop. Right now! I did it once from a slow speed to see how good they grab. Very good is the answer! g You would have major flat spots if you did it from any great speed! snip Definately not like truck brakes than. Like BushyPete said having the brakes engage if I lost air pressure would be a disaster. Probably ground loop the plane or worse. Greg in AL |
#204
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How do you find the limits of areas on a chart?
"Jim Macklin" writes:
Boundaries: Beginning at 39° 12' 30"N lat., 86° 09' 50"W long., to 39° 07' 36"N lat., 86° 08' 00"W long., to 39° 07' 36"N lat., 85° 59' 30"W long., to 39° 00' 00"N lat., 85° 59' 30"W long., to 38° 57' 48"N lat., 86° 01' 29"W long., to 38° 57' 48"N lat., 86° 16' 06"W long., to 39° 06' 00"N lat., 86° 15' 00"W long., to the point of beginning. All well and good, but rather awkward to review in the air (or even on the ground). -- Transpose mxsmanic and gmail to reach me by e-mail. |
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