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Guest bluez87

P51 Takeoff problems - Acceleration

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I read the previous post on this same subject posted by Stan dated 10-28-07 and the responses. Unfortunately, I continue to have problems. 1. I have tested all other aircraft and all of them takeoff without any problems.2. I recalibrated the joystick.3. I have tried every possible combination that I know. with/without flaps with/without trim stick held back or at neutral (no difference) with/without right/left rudder at 0, 5, and 10 degrees. slowly advance throttle to taxi speed;60%;full tailwheel lock on/offThe result is always the same. The plane immediately begins a left turn and continues in a left circle no matter what is done or what setting is used.I have the same experience Stan had. After forcing the plane into the air going across a vacant field beside the runway, the plane handles normally in the air, responds correctly when landing, and stays straight on the runway during the rollout. The problem only occurs during takeoff.Once again, I have no problem with any other aircraft. Am I overlooking something?Also, is there any way to tell if the tailwheel is locked? I couldn't find any lever or indicator in the cockpit that showed this. Thanks,Dennis

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Thanks for the suggestion. I forgot to add that I had done that. I normally fly at the Hard setting. However, I did try it with the easiest setting and still the same problem.The only thing that I have as an addon is Ultimate Traffic and Ultimate Terrain, but once again, no other aircraft in the Acceleration package has any problems.Thanks,Dennis

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Don't go to full throttle. You don't need it. The engine in that plane has tremendous power and tremendous torque at full throttle. If you are doing circles at ~30% power, then you have another problem.45-50" Hg MAP should be all you need.

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It's called engine torque and that is what is causing you to pull to the left during take off.Do not apply full throttle during takeoff (or you will most definitely make an abrupt left turn), you'll actually want to push forward on your stick a bit to bring the nose down and the tail up. Don't go so far as to push the nose into the deck just get the plane in a level attitude with the main gear on the deck. Once the tail is up you can use the rudder to counter act the engine torque and slowly apply throttle as needed to get airborne.

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For the stock airframe 45" of boost and 3000rpm is the take off configuration.Takeoff Maximum is 61" and 3000rpm.But this isn't a stock airframe. It's much lighter, the wingspan is clipped, and it's got literaly twice as much horsepower. In a stock merlin 67" of boost is War Emergency Power, the maximum allowable manifold pressure. These Stang's run nearly 160" of boost.Apply 45" of boost @ 3000rpm. Rudder trim 5 degrees nose right. Locked tailwheel, hold stick rearward untill at least 60 knots indicated airspeed before lifting tail. Be ready on the right rudder pedal. Advance the throttle gently so as to prevent engine torque from causing adverse yaw before sufficient airspeed is reached to aerodynamicaly counteract said yaw.

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Sounds like the rudder/tailwheel is not reponding to your inputs. Confirm that it is.

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You have to use the rudder controls, it is ins on the keypad for left and enter for right. Make sure numlock is turned off and tap it do no hold it, best to get in spot view and watch the reaction after awhile it is pretty easy.Happy Flying!

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Dennis,One factor that hasn't been mentioned is "P" Factor. Sitting on the ground, the P-51 has a pronounced tail low attitude. P Factor is the condition where the downswinging blade on the propeller has much more angle of attack and therefore much more pull than the upswinging blade on the other side. This is what creates the left turning motion. You just add power slowly at a rate which your available rudder can control it. Once you raise the tailwheel, most but not all P Factor goes away.By the way, this is the same reason you need slight right rudder in climb out in your 172.

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Thanks to everyone for all of the advice. As I noted in my initial post, I had already tried taking off at various thrust powers, setting the rudder, tailwheel locked, etc.Good ideas were offered by everyone and will be helpful to others who might be having related problems.However, in my case, I belive that "SolarEagle" is correct in the observation that it appears the rudder control input is not working. The fact that it occurs only on the P-51 indicates a possibly corrupt file or conflict with something unique to my setup.No other problems with Acceleration and still consider it as being well worth the money.Once again, thanks for all of the input.Dennis

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