Originally posted by Toad
Yeah, that Aces High test shows the D9 and the 51 almost identical when clean.
Now add 2K+ to the 51. Sorta like the AAF wanting to add 2k to the P-38 in the dive tests because "The extra weight would cause additional acceleration of the aircraft during its dive" and as the RC guy said "Weight becomes a component of thrust when the plane is in a dive."
Now, drag from bombs and rockets is clearly there and it will increase with speed.
Will it increase enough to offset the "additional accleration"? I have no idea. I don't know what the drag is or what the accleration would be.
Well first get the argument right. We're not arguing the
accelleration, we're arguing the top speed.
Originally posted by Toad
I have no idea how long Hazed followed him down, what alt they started at or any of the details.
They stared out co-E (max level speed), co-alt and dived from 20k to the deck, the D9 was in compression and shaking bad doing 650 mph, and the P-51 was opening the distance.
Originally posted by Toad
But the Jug acclerated like a Banshee in a dive, in fact that's one of it's hall marks. It was the heaviest fighter of it's time and it certainly wasn't the "cleanest" one out the wrt to drag.
so, I don't think you can simply discount this.
Yes the Jug was awesome in dives, but not
fast, a Spit for instance would catch up eventually given enough alt.
Originally posted by Toad
BTW, the area below 60K is far from a vacuum, so toss out that red herring. It's already smelly.
Airplanes DO NOT operate in a vacuum.
... oh, and thrust is "that other force" that's acting.
It is not a red herring. Even in an dense atmosphere two different objects will accelerate equally in the beginning. If you drop a B-17 and a Zeke from 10k they will both start to pick up speed pretty much equal because the air resistance/drag isn't powerful enough to matter much. At this stage engine power tempered by mass is the major factor in dive accelleration. The Jug had a very powerful engine.
As speed and drag builds up mass becomes a factor. The Jug was very heavy for a fighter, it weighs almost as much as the 110 (!). Its mass would allow gravity to cancel out much of the drag force. At this point other lighter fighters would start to accelerate slower.
As speed reaches high sub-sonic levels drag becomes the dominant factor. The force of air exceeds the weight of the aircraft by so much that only two things become important: aerodynamics and power. The Jug had power in spades, but it also ploughed through the air like a ... big milk jug
. At this stage more aerodynamic aircraft like the Spit, P-51, D9 and others would be able to outpace the Jug in a dive.
The P-51 and the D9 is very well matched up. The P-51 weighs 200 lbs more, but the D9 has more power, and they're both aerodynamic masterpieces. Now, if you add 2000 lbs of bombs and 6 rockets the P-51 clearly has the advantage in the "middle" speed range of the dive, but as speed builds up to silly-levels like 650 mph the extra parasitic drag of this ordnance would give the D9 a distinct advantage. At those speeds the airflow around the nose of the bombs would be supersonic due to the bluntness and width of WWII bombs. This would create massive drag that would most likely rip the pylons off, if not the wings themselves. The interference drag caused by the rockets would also be extreme and I doubt very much that the outer wings could take that much extra drag. Directional stability would be horrible, and I for one can't understand why the P-51 didn't shake itself apart. But most important of all is the fact that the P-51 doesn't have the power to overcome the extra drag.
The D9 should be the fastest of the two.
I have often wondered if ord. drag is correctly modelled in AH. I know the weight is there, but I have never really noticed the effect of added drag.
