ESM P-51 D
02-20-2012, 05:13 PM
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ESM P-51 D
Has anyone found the correct measurement for the CG on a ESM P-51 D? The point where the instructions show seems to be to far aft. My plane seems to way nose heavy. That is unusual for a warbird.
02-21-2012, 12:24 AM
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RE: ESM P-51 D
Hello Barnstormer,
I'm not 100% sure what you are trying to say in your post, but hopefully this might help.
If you mean that when you support the model at the plan balance point it hangs nose down then yes the model is nose heavy. Move weight aft or add weight to the tail. the fact that the model hangs nose low doesn't necessarily mean that the plan balance point is to far aft, it just means that you have to change the model.
If you mean that when you fly the plane it flys nose heavy but it is balanced at the plan balance point, then the plan point is too far forward not aft. Feel free to shift the balance to suit your flying style (within limits). Again this doesn't necessarily mean that the plan is wrong, often manufacturers will err on the nose heavy side for a safer maiden flight.
If you have some reason to doubt ESM's balance point (and it wouldn't be the first time a manufacturer has got it wrong) then use one of the online CG calculators with a 5 to 15% margin forward of the neutral point to establish a safe balance point. Support the model at this point (it,s easier and more accurate to balance low wing models upside down) and add or remove weight or shift weight around until the model hangs level.
Hopefully some one will chime in and either confirm the plan balance point or give you one that works for them, but if not the online calculators work really well and are very easy to use.
Sorry if I've misunderstood your post, or if all this is stuff that you already know.
Dave H
I'm not 100% sure what you are trying to say in your post, but hopefully this might help.
If you mean that when you support the model at the plan balance point it hangs nose down then yes the model is nose heavy. Move weight aft or add weight to the tail. the fact that the model hangs nose low doesn't necessarily mean that the plan balance point is to far aft, it just means that you have to change the model.
If you mean that when you fly the plane it flys nose heavy but it is balanced at the plan balance point, then the plan point is too far forward not aft. Feel free to shift the balance to suit your flying style (within limits). Again this doesn't necessarily mean that the plan is wrong, often manufacturers will err on the nose heavy side for a safer maiden flight.
If you have some reason to doubt ESM's balance point (and it wouldn't be the first time a manufacturer has got it wrong) then use one of the online CG calculators with a 5 to 15% margin forward of the neutral point to establish a safe balance point. Support the model at this point (it,s easier and more accurate to balance low wing models upside down) and add or remove weight or shift weight around until the model hangs level.
Hopefully some one will chime in and either confirm the plan balance point or give you one that works for them, but if not the online calculators work really well and are very easy to use.
Sorry if I've misunderstood your post, or if all this is stuff that you already know.
Dave H
02-21-2012, 01:20 AM
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RE: ESM P-51 D
CG at 130 mm from leading edge (see picture). Depending on your particular setup, you could need some weight in the tail. This one needed 60 gr bolted in the tail. Very good flyer with this CG.
Regards
