How do I measure Thrust Angle?
10-17-2006 | 04:32 PM
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From: Westfield,
MA
How do I measure Thrust Angle?
Hi all!
I have an Accell Katana 40 size Profile and just put a Saito 80 on it. On first flight it took a lot of up elevator trim and a lot of right trim to get it to fly straight and level. I brought it home and checked balance again and it was way off. Lateral balance was heavy to the left and it took an ounce of lead on the tail to get the CG at 120mm from the lead edge of the wing. I want to check the thrust angle before I bring it out again after finding my original set up so far off. I had to dremel the mount to get the 80 to fit in it and am wondering if I didn't mess up the original angle. When I tried a roll, it made like a giant cork screw in both directions. I just read a post a week or 2 ago that told how to measure from a mark on the prop X inches from the center , then measure the distance to the wings edge on the right side and compare it to the measurement on the left side. It had the angle figured out by the difference in the two sides. I have searched high and low and can not find this post and was not smart enough to save it. Anyone have any tips or suggestions to measure to see where I'm at.
Thanks for any help,
Peter
I have an Accell Katana 40 size Profile and just put a Saito 80 on it. On first flight it took a lot of up elevator trim and a lot of right trim to get it to fly straight and level. I brought it home and checked balance again and it was way off. Lateral balance was heavy to the left and it took an ounce of lead on the tail to get the CG at 120mm from the lead edge of the wing. I want to check the thrust angle before I bring it out again after finding my original set up so far off. I had to dremel the mount to get the 80 to fit in it and am wondering if I didn't mess up the original angle. When I tried a roll, it made like a giant cork screw in both directions. I just read a post a week or 2 ago that told how to measure from a mark on the prop X inches from the center , then measure the distance to the wings edge on the right side and compare it to the measurement on the left side. It had the angle figured out by the difference in the two sides. I have searched high and low and can not find this post and was not smart enough to save it. Anyone have any tips or suggestions to measure to see where I'm at.
Thanks for any help,
Peter
10-17-2006 | 04:43 PM
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From: tulsa,
OK
RE: How do I measure Thrust Angle?
Ok i think i know what your problem is first off ill tell you my setup.. I have the accel katna gs 40 and a saito .56,2 standard futaba s3004's,and some futaba digitals on the tail, A sanyo nihm 4.8 volt 1850 mah battery. Mine balances perfect and it didnt take any trim to get it to fly perfect. OK back to your problem how far foward is your engine mounted? Also what is your total weight? Posting some pictures would help us to find your problem.
10-17-2006 | 08:22 PM
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From: Westfield,
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RE: How do I measure Thrust Angle?
Z,
My engine is about centered in the fuse. It is 3/4" from the back of the spinner to the front edge of the fuse. The mounting holes are both about the same distance to the edge of the motor cut out in the fuse. I would have mounted it back a little more but with the carb in the back I didn't want the throttle linkage to be at too steep an angle or too short. I am not able to get a picture of it tonight, I'll try to get a couple tomorrow. When I measured the prop to the front edge of the wing, both sides were pretty close to the same, maybe 1/32 difference at most.I measured it with a steel rule so it's only as accurate as my eye! I had an OS 70 ultimate on it and it balanced with 1/4 ounce on the tail to get CG at 120mm. There were 2- 1/4 ounce weights glued to the outside edge of the right wing. It balance lateraly with the 70 on it, but when I checked again with the 80 Saito it was heavy to the right. I took both weights off and it balanced perfectly. The Saito seems much heavier than the Ultimate so I wasn't too worried about the lead in the tail. I figured that seemed to make sense with a heavier motor. I don't know the total weight of the completed plane.
Thanks,
Peter
My engine is about centered in the fuse. It is 3/4" from the back of the spinner to the front edge of the fuse. The mounting holes are both about the same distance to the edge of the motor cut out in the fuse. I would have mounted it back a little more but with the carb in the back I didn't want the throttle linkage to be at too steep an angle or too short. I am not able to get a picture of it tonight, I'll try to get a couple tomorrow. When I measured the prop to the front edge of the wing, both sides were pretty close to the same, maybe 1/32 difference at most.I measured it with a steel rule so it's only as accurate as my eye! I had an OS 70 ultimate on it and it balanced with 1/4 ounce on the tail to get CG at 120mm. There were 2- 1/4 ounce weights glued to the outside edge of the right wing. It balance lateraly with the 70 on it, but when I checked again with the 80 Saito it was heavy to the right. I took both weights off and it balanced perfectly. The Saito seems much heavier than the Ultimate so I wasn't too worried about the lead in the tail. I figured that seemed to make sense with a heavier motor. I don't know the total weight of the completed plane.
Thanks,
Peter
