AcesHigh Fighter comparison Models

[drgondog]

Apologies, then. All the P-51B comments seem to run together at some point. I saw your previous reply about the mid war arena and then this one and mis-read your intents.


My bad.

Not bad.. makes sense..

Having said that, my father preferred the B w/1650-7 as the better performer and it was even better as the fuel load reduced.  Post war, when he was at Gablingen he made several flights in the 'local Fw 190D-9' along with several other high time ace pilots of the 355th and preferred the B over the D in the rat races.

[smoe]

If the D wing was larger than the B this would explain the better turn and climbing performance. 

Anyone find a wing surface area chart for both?

[Widewing]

If the D wing was larger than the B this would explain the better turn and climbing performance. 

Anyone find a wing surface area chart for both?

Except that the B is a better turner than the D, and climb performance varies between the two due to having different superchargers. Overall, the B is a better climber.

[drgondog]

Not wrong but: B and D wing the same, both used the 1650-7 engine from May 1944 through end of war.

The primary reason the B turned and climbed better for the above condition and spec is that the B had two fewr .50's and associated ammo - all else the same - therefore at ~300 less GW it should climb and turn slightly better as well as have a little ecess power available when the D tapped out - therfore more energy available to the B.

[Widewing]

Not wrong but: B and D wing the same, both used the 1650-7 engine from May 1944 through end of war.

The primary reason the B turned and climbed better for the above condition and spec is that the B had two fewer .50's and associated ammo - all else the same - therefore at ~300 less GW it should climb and turn slightly better as well as have a little excess power available when the D tapped out - therefore more energy available to the B.

The P-51B/C was lighter than the P-51D even before guns are installed, IF it lacks the fuselage tank. The Aces High P-51B has the fuselage tank (see below).

Empty weight for the P-51B is 6,988 lbs.
Empty weight for the P-51D is 7,205 lbs.

Basic weight, with gun installation, trapped fuel and oil is:

P-51B/C: 7,325 lbs (with the fuselage tank installed, basic weight is 7,580 lbs.)
P-51D: 7,673 lbs.

[drgondog]

Agreed WW

[Brooke]

http://gonzoville.com/ahcharts/index.php

I just looked these over and have a major question to pose.

Why is the performance of the P-51B below the D in both climb and turn? 

The B's performance according to that site is better than the D (by a little bit) as the chart is giving turn radius instead of turn rate.

The B's climb rate is slightly less than the D until about 10k alt, then it is better.  My guess is that it has nothing to do with wings or airframe and more to do with how the engines/superchargers are set up (i.e., their tuning and what gearing is chosen).

[drgondog]

Brooke - if the B is modelled with the 1650-3 engine, the two stage supercharger gears were optimised for higher altitudes but the Bhp was less for TO and Low Blower/High Blower Critical altitude than the -7...

 so the comparisons would not favor a P-51B-1, -3 and -5 versus a P-51B-7 through -15 as they earlier models reached the ETO with the 1650-3 and weren't retrofitted until the last -7s and all succeesding B/C came off the line.

The model of the B in AH would be relevant for Dec 1943 through April 1944.  From May, 1944 to the EOW all the B/C/D/K's had the 1650-7 and the B/C's were approximately 300 pounds less GW for all comparable fuel load outs.

[drgondog]

Forgot to mention the fact that the middle of the -5 block was separated into the -7 by virtue of adding the internal 85 gallon fuel tank (the earlier 51B-1, -3 and -5 had field mods applied in March 1944) and the 1650-7 engine and those deliveries hit the ETO in April, 1944.

The simple comparisons between the B/C and D/K in May 1944 as they came off the production line was 4x50  versus 6x50 cal guns (at 69 pounds each) and 1260 versus 1880 rpg 50 cal ammo (at 3 rounds/pound). 

69 pounds per gun x 2 = 138 pounds. 620 rounds x .333 =206+ pounds -------> 344 pounds 'Delta' lighter for the B/C with 1650-7 versus the D/K with the 1650-7.