Dynam P-51D 1200mm CG

[Phantom]

I'm about to maiden my Dynam P-51D Mustang which is supposed to have a 70-75mm back from the wingroot leading edge CG per the manual, with a 2200mah 3s 20c lipo installed, pushed all the to the front of the nose. I have not modded this plane at all, which for me is saying something lol. But even stuffing a 4000mah 3s 25c lipo all the way to the front leaves me with aft CG, somewhere around the 85-90mm range. Anyone else experience this? Anyone have this bird and fly with another CG apart from the manufacturer's recommended 70-75mm? I saw a you tube video of pilot Ryan flying it and he states, "Just throw in a 2200mah 3s lipo all the way to the front, and you're good to go."

[fhhuber]

Never had a problem getting CG with the OEM RTF package battery up to 4S 4000 mah.

The airplane does like a little more weight than the 2200 mah 3S. But its more for wind tolerance than for CG. Best results have been appx 3000 mah.

My current one is probably close to 5 years old. Upgraded to the Dynam Me109 motor, 4 blade prop from the discontinued Corsair (might be the same prop used n the current Dynam P51) Du Bro spinner because the old version (as in your picture) had 3 blades and you couldn't modify that spinner for 4.

I flew the plane with original motor and prop on 4S with no problems. Upgraded the motor so I could have 4 blades and not burn the motor up on 4S. I did open up some added cooling air flow through the fuselage for the motor and ESC.

EPO, being an expanded foam, does result in varied density of the foam in some cases. I have seen a few Dynam P-51's and none that couldn't get CG in flyable range with just shifting the RTF package 3 cell pack. I balance my current model on the rear screws mounting the retracts. You can't go much further forward without having issues nosing over trying to take off.

[Phantom]

Never had a problem getting CG with the OEM RTF package battery up to 4S 4000 mah.

The airplane does like a little more weight than the 2200 mah 3S. But its more for wind tolerance than for CG. Best results have been appx 3000 mah.

My current one is probably close to 5 years old. Upgraded to the Dynam Me109 motor, 4 blade prop from the discontinued Corsair (might be the same prop used n the current Dynam P51) Du Bro spinner because the old version (as in your picture) had 3 blades and you couldn't modify that spinner for 4.

I flew the plane with original motor and prop on 4S with no problems. Upgraded the motor so I could have 4 blades and not burn the motor up on 4S. I did open up some added cooling air flow through the fuselage for the motor and ESC.

EPO, being an expanded foam, does result in varied density of the foam in some cases. I have seen a few Dynam P-51's and none that couldn't get CG in flyable range with just shifting the RTF package 3 cell pack. I balance my current model on the rear screws mounting the retracts. You can't go much further forward without having issues nosing over trying to take off.

Thank you for your reply, since the stock PNP only comes with a 30amp esc, I'll have to stick with the 3s unless I upgrade like yourself in the future. I'm waiting for the necessary items to come in stock on Motion RC, for the upgrade to 4 blade, I wouldn't mind the extra ground clearance, not to mention the looks. I guess I misspoke when I said I haven't made any mods, I did in fact open up the lower portion of the cowling under the spinner for cooling. I'll fly her like she is, and hope for the best. Thanks again for info Fhhuber.

[fhhuber]

Thank you for your reply, since the stock PNP only comes with a 30amp esc, I'll have to stick with the 3s unless I upgrade like yourself in the future. I'm waiting for the necessary items to come in stock on Motion RC, for the upgrade to 4 blade, I wouldn't mind the extra ground clearance, not to mention the looks. I guess I misspoke when I said I haven't made any mods, I did in fact open up the lower portion of the cowling under the spinner for cooling. I'll fly her like she is, and hope for the best. Thanks again for info Fhhuber.

Opening the hole under the spinner does no good if you do not open an air exit behind the wing.

Look for pictures of the P-51 with the lower radiator rear opened.
Pilots used opening this suddenly to make the P-51 "jump" out of enemy gunsights or to otherwise affect maneuvers. Not exactly what it was made for but it was very effective.

[Phantom]

Opening the hole under the spinner does no good if you do not open an air exit behind the wing.

Look for pictures of the P-51 with the lower radiator rear opened.
Pilots used opening this suddenly to make the P-51 "jump" out of enemy gunsights or to otherwise affect maneuvers. Not exactly what it was made for but it was very effective.

Logic rules, I'll open one up on the buttom right behind the scoop, as the epennage tapers, should create a good vacuum in that area. Thanks for the tip.

[fhhuber]

Logic rules, I'll open one up on the buttom right behind the scoop, as the epennage tapers, should create a good vacuum in that area. Thanks for the tip.

Check this picture

I made my rear opening to look like this

http://www.ipmsstockholm.org/magazin..._p51_f_002.jpg

[Phantom]

Check this picture

I made my rear opening to look like this

http://www.ipmsstockholm.org/magazin..._p51_f_002.jpg

Wow! That's a heck of a lot more pronounced than what I was orginally going for. But I kind of like it... I'll get right to carving adding that exhaust scoop after I finish building/modding my E- flight F-15C. Once I get started on something, it's hard for me to put it aside until it's complete. The EDF's it came with are a joke so I dug her out a bit, and she's now sporting a pair of 12 bladed 70mm's, gonna run on 4s.

[fhhuber]

Ensure the bigger fans have adequate air intake...

[Phantom]

Ensure the bigger fans have adequate air intake...

I don't think that will be a problem, even the anemic EDF's it came with had these two huge cheater holes in front of them.