Austria Posted September 15, 2003 Report Posted September 15, 2003 Can anyone tell me why some pilots take one pedal off and turn it around while the aircraft is on the ground?! Thanks in advance, safe flights...Oh, I forgot to mention that I am talking about the MD 500 mainly.. don't know about the other types... Andy ??? Quote
helotech Posted September 16, 2003 Report Posted September 16, 2003 This is mainly for when you get out of the acft. when it is running. There is a spring that pulls the left pedal forward there by adding full pitch to the T/R when your feet are not on the pedals. So buy turning the pedal around it is stopped by the other pedal from creeping forward. In my opinion, a better and easier way is to use a bungie to hold the pedal back. Just make sure that it can not come off. Quote
HeliMark Posted September 16, 2003 Report Posted September 16, 2003 To add to Helotech, by doing the pedal switch (which I use) or bungee or several other methods I have seen, is to reduce the strain on the engine/tail rotor componets. Without doing it, the engine will usually lose 100-200 RPM (Nr) due to the increase of pitch in the tail rotor, and if you are running a low idle for some reason, N1 can run low enough that you flame out. The NOTAR does not need this as there is no springs to assist in pedal pressure and will stay centered by itself. Quote
Flying Pig Posted March 13, 2004 Report Posted March 13, 2004 When I was learnin' the 500, and we had a small insert that fit between the two pedals to keep them centered. It looked like a small horse shoe. It fit in the holes on top of the pedals. I was taught that when the helicopter is shut down, and you dont center the pedals (and lock them somehow) it can warp the straps in the tail rotor. Ive seen several photos of 500's and you can see the tail rotors are fully pitched when the bird is shut down. Indicating they dont center them. Quote
HeliMark Posted March 13, 2004 Report Posted March 13, 2004 Flying Pig, I do not understand why they said that the straps would warp. When the tail rotor is centered, the straps have no twist to them. When they are left with the left pedal forward (which I do), they would have the twist that could lead to a warp, although our chief mechanic said that in 30 years he has yet to see it happen. When the Nr drops below about 150 rpm, I let the left pedal go full forward to assist in slowing the rotor down. With the pedal centered, a little wind, and no rotor brake it can take a bit of time for the rotor to stop. I do not like to let the pedal forward before 150 rpm to reduce the stress. Quote
Flying Pig Posted March 13, 2004 Report Posted March 13, 2004 Opps, sorry, my post was a little unclear........ Thats what I meant. I was taught that if the pilot let the pedals go uncentered, and the blades were left pitched for long periods, the straps could warp. I was also told that it would take A LONG time to actually damage the straps, just a preventative measure. Quote
JGB Posted April 29, 2004 Report Posted April 29, 2004 The real reason this is done is that a D model will spin around to the left on a slick surface (ice). Turning the pedal is the best option. I don't agree with the U shaped device that some people use and neither does the guy who took off with it in place who now has no function in his left arm. The bungee spring is there to offset the camber on the blade. A 4 blader has a bungee spring which overcentres and will go in either direction. Some care is required on the 4 blader. Quote
Flying Pig Posted April 30, 2004 Report Posted April 30, 2004 With the U shape device, there was a long red rope attached to it, that in turn was attached to a red cover that went over the cyclic with the Remove Before Flight tag. Quote
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