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I doubt any production P-47 did 500 mph, maybe 480 w/out wing pylons for the P-47M, but that's pushing it.
The XP-47J did do 507 mph at 32,000 ft iirc. Though this was also in the razorback configuration which had less drag than the bubbletop. (hence why bubbletop P-47's and P-51's were generaly slower than their razorback counterparts)
The P-51H featured a new prop an a MUCH more powerful engine than the P-51B/C, hence its superior speed. (To go from 1,790 HP to 2,280 HP is quite a jump!)
KK is right about the bubble canopy, it creates suction and thus drag, and that is why the razorbacks are slightly faster.
KK- I suspect the added 600+ pounds of weight for the tear drop top P-51D had a lot more to do with the slight drop in airspeed and climb and turn... and how would you account for a 51H being 20-40mph faster than the P-51B/C at the same weight? (The 1650-9 was slightly more powerful at altitude than the -3 but other than that)?
Otherwise I don't have the drag figures for the H so I am NOT claiming aerodynamics is the sole factor.
I think by "suction" Soren meant the lower preassure on the aft part of the bubble canopy (a slight vacuum), similar to the phenomon at the tail of a bullet.
The phrasing seems a little confusing, but I assume the added 600 lbs from going to the B to D Mustang. (I don't think switching to the Bubble canopy changed weight much)
No, the Bubble canopy effectively was offset by removing the extra top bulkhead/skin and stringer of the P-51B 'turtleback'. The bigger increases were beefed up spar for vertical stabilizer and adding two more 69 pound M-2's plus 700 rounds of .50 caliber ammo..
The worst result of removing the turtleback was slight loss of yaw stability requiring first a 'dorsal' fin modification the the production P-51D-5 tail, then a permanent change for all succeeding D/K models, and then a new, 'taller tail' for the P-51H
The bubble canopy was one of the reasons in drop in speed. Plus weight has a much larger effect on climb than speed. Streamining has the opposite effect. (speed much more than climb)
In my opinion it (bubble canopy) had the opposite effect and at worst was neutral based on Lednicer's model. As far as weight, remember that for same relative speed, Lift (and therfore Induced Drag) is increased for the heavier aircraft.. so that an airplane with exactly the same engine with the same basic aero flown at same speed (and Lednicer says the 51B and D had the same wetted drag coefficient) the heavier bird will not perform as well
On the P-47 the bubble canopy lost it ~5 mph top speed. The wing pylons cut 10-15 mph off speed. (much more on early versions, though not on any standard production versions iirc)
The nose of the P-47J helped speed as well. (prabably added ~20 mph)
No, the Bubble canopy effectively was offset by removing the extra top bulkhead/skin and stringer of the P-51B 'turtleback'. The bigger increases were beefed up spar for vertical stabilizer and adding two more 69 pound M-2's plus 700 rounds of .50 caliber ammo..