P Factor and engine offset
07-19-2007 | 12:54 PM
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From: Dickinson,
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P Factor and engine offset
How much offset will i need for a Seagull Harrier 3D using a Evolution 100 engine? Will it work if I put a washer behind the engine mount on the left side between the mount and firewall. Is the left side correct? Please help!!!
07-19-2007 | 02:00 PM
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From: Meridian, ID
RE: P Factor and engine offset
Right Thrust is dependant on several things. 2 degrees is good starting point.
Some people are such good flyers that they can correct in any flight attitude with rudder and use no engine offset.
But if you don't know what to look for, how will you ever know it is correct for YOUR plane? See http://www.rcaerobats.net/trim_chart.htm
Some people are such good flyers that they can correct in any flight attitude with rudder and use no engine offset.
But if you don't know what to look for, how will you ever know it is correct for YOUR plane? See http://www.rcaerobats.net/trim_chart.htm
07-19-2007 | 02:23 PM
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From: Hampton,
GA
RE: P Factor and engine offset
I would of thought the Harrier would of had built in right thrust already. But to add yes washers work perfectly behind engine mount. to measure use a protractor and you should be good to go. Here is a link to a paper protractor to print out. Works good to tape to plane- http://www.ossmann.com/protractor/co...protractor.pdf
07-19-2007 | 02:42 PM
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From: Dickinson,
ND
RE: P Factor and engine offset
Thank you both VERY MUCH for your help!! I don't know if the Harrier has built in right thrust or not, but i didn't use the kit engine mount. I bought a Du-Bro engine mount and had to drill it out to mount the engine my holes were probably off a slight bit, I had them as close as possible but 2deg is not much to the human eye. So if i was off 2 deg in the wrong direction that would have made the total correction I need about 4 deg, I'll try a washer then check until I get it right. Thanks again.
07-20-2007 | 02:19 PM
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From: Kershaw, SC
RE: P Factor and engine offset
True 3D and pattern planes don't have right or downthrust. Try to hover with right or down thrust. Even with a gyro, the plane will still drift. A HAKE to the left would be easier than the right. Even a regular knife edge would be difficult to pull off. Besides, the P factor with say a X4W or X6W prop isn't near as bad as a 6 or 8. It just gets some getting used to...
07-21-2007 | 04:31 PM
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RE: P Factor and engine offset
I don't know about pattern planes but nearly all of the TRUE 3d planes I have seen or heard of have right thrust. You can hover fine without it, you just have to hold some right rudder in while you do it. That is just harder to do. I hear Chip Hyde uses no right thrust but programs right rudder to throttle mixing. Paul Swanson recommends 3 degrees right on Mojos of all sizes. UCD's come with 3 deg rt thrust built in, as do most ARFs. I have tried it all and now have 3 deg right thrust in all of my planes.
07-21-2007 | 09:43 PM
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From: Kershaw, SC
RE: P Factor and engine offset
ORIGINAL: Jack Hyde
I don't know about pattern planes but nearly all of the TRUE 3d planes I have seen or heard of have right thrust. You can hover fine without it, you just have to hold some right rudder in while you do it. That is just harder to do. I hear Chip Hyde uses no right thrust but programs right rudder to throttle mixing. Paul Swanson recommends 3 degrees right on Mojos of all sizes. UCD's come with 3 deg rt thrust built in, as do most ARFs. I have tried it all and now have 3 deg right thrust in all of my planes.
I don't know about pattern planes but nearly all of the TRUE 3d planes I have seen or heard of have right thrust. You can hover fine without it, you just have to hold some right rudder in while you do it. That is just harder to do. I hear Chip Hyde uses no right thrust but programs right rudder to throttle mixing. Paul Swanson recommends 3 degrees right on Mojos of all sizes. UCD's come with 3 deg rt thrust built in, as do most ARFs. I have tried it all and now have 3 deg right thrust in all of my planes.
