The XB-42 was an experimental bomber developed during WW2. Its twin engines delivered a combined 3,800 HP and top speed of 410 mph at 23,440 ft.
It's an amazing aircraft. But if an enormous aircraft is that fast why not use the same concept for smaller fighter-sized aircraft? I assume there must be a good reason because it didn't happen.
I used a modified version of the drag equation found on NASA's website to estimate the speed increase if the front profile was reduced by 50% and everything else stayed identically the same. The modified version can be found here.
By reducing the front profile by 50% the top speed increased by 25.99%. That brought its top speed up from 410mph to an amazing 517mph. That's almost as fast as a jet. Is that possible or am I missing some other aerodynamic force that would stop the plane from approaching that speed?
I guess at the most basic level is this concept correct?
Smaller frontal area = faster top speed.
Is there some other aerodynamic force that would negate that?
Answer to comment below: Zeus answered that reducing the aircraft's profile wouldn't make a significant difference because most drag was produced by the wing. Yes and no. Wing lift does produce a lot of drag at low speed but that drops as the plane accelerates. At high speed nearly all drag is parasitic (i.e. the shape of the aircraft) as evidenced by the chart below. Moreover my question was theoretical. If 50% of the plane's profile was removed the weight could be removed as well and with it the wing size. Turning the XB-42 airframe into a small, fighter aircraft was the general point of the question.