Boomerang XL CG
07-08-2007 | 12:04 PM
#2
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From: St Louis, MO
RE: Boomerang XL CG
According to Alan-designer..
At the bulkhead just forward of the turbine.
Wheels down, tanks empty, hatch off. (UAT can be full or empty, makes no noticable difference). That bulkhead is as far back as you need to go for good safe aerobatics.
Jack
At the bulkhead just forward of the turbine.
Wheels down, tanks empty, hatch off. (UAT can be full or empty, makes no noticable difference). That bulkhead is as far back as you need to go for good safe aerobatics.
Jack
07-09-2007 | 03:45 AM
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From: Newport PagnellBUCKS, UNITED KINGDOM
RE: Boomerang XL CG
jetalot
I found the recommended CG very/too conservative. So much so, that I stalled on landing damaging the front U/c (JetA1) at quite a low angle of attack.
Talked to Ali about it and he said that CG is far from critical and to start reducing the ballast out the front until I felt comfortable. This happy state occurred when I had taken 500grms out the nose and battery area.
I would suggest you fly cautiously at first and keep the landing speed up until you are confident that she will hold your normal landing AOA without a stall. I took out 200grms a time. After that she flatters your flying something rotten!
My other caution is to check the piece of ply holding the canopy at the back. Mine did a premature release in flight. To be really safe - I would cut away the existing epoxy and replace with Hysol.
I found the recommended CG very/too conservative. So much so, that I stalled on landing damaging the front U/c (JetA1) at quite a low angle of attack.
Talked to Ali about it and he said that CG is far from critical and to start reducing the ballast out the front until I felt comfortable. This happy state occurred when I had taken 500grms out the nose and battery area.
I would suggest you fly cautiously at first and keep the landing speed up until you are confident that she will hold your normal landing AOA without a stall. I took out 200grms a time. After that she flatters your flying something rotten!
My other caution is to check the piece of ply holding the canopy at the back. Mine did a premature release in flight. To be really safe - I would cut away the existing epoxy and replace with Hysol.
07-14-2007 | 02:37 AM
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From: Newport PagnellBUCKS, UNITED KINGDOM
RE: Boomerang XL CG
highhorse
YES - When you have Crowe braking as well, the wing efficiency is much reduced. With a lot of nose weight and the tailplane having to balance it all - it was just too much. Landing speed was a little greater than I normally use for the Intro. Hence my surprise and annoyance.
I have now cut the Crowe braking a bit, as well as reducing the nose weight. She now lands every bit as gently as the Intro and is a delight.
I think Alan is anxious that people do not start with a dangerously aft CG and thereby lose the model. I suspect I would be equally conservative if I was him. If you treat the recommended CG as a good starting point and reckon to work off a little bit at a time until you have it balanced the way you feel comfortable - then you will finish up a very happy man. Just remember to make the first few landings quite fast and/or test for a stall at a good hight so you know what to expect.
YES - When you have Crowe braking as well, the wing efficiency is much reduced. With a lot of nose weight and the tailplane having to balance it all - it was just too much. Landing speed was a little greater than I normally use for the Intro. Hence my surprise and annoyance.
I have now cut the Crowe braking a bit, as well as reducing the nose weight. She now lands every bit as gently as the Intro and is a delight.
I think Alan is anxious that people do not start with a dangerously aft CG and thereby lose the model. I suspect I would be equally conservative if I was him. If you treat the recommended CG as a good starting point and reckon to work off a little bit at a time until you have it balanced the way you feel comfortable - then you will finish up a very happy man. Just remember to make the first few landings quite fast and/or test for a stall at a good hight so you know what to expect.
