On 09/13/2010 06:06 AM, Jim Wilkins wrote:
On Sep 13, 7:20 am, Pete wrote:
...
The P-38 didn't need a performance boost primarily because it was
turbocharged. The P-39 was hamstrung by its Allison because the Army,
in its infinite wisdom had the two speed supercharger replaced with a
single speed supercharger, which really limited performance at
altitude. The P-38 didn't have that problem.
...
Pete Keillor

The P-38 and P-39 were both designed to the same request for an
interceptor. The 38 was more promising so the 39 was repurposed for
ground attack, partly to keep Bell from closing. At low altitude the
P-39 was good enough to tangle with a Zero with some chance of
success. If you look at the power vs altitude chart referenced in my
other post you'll see that the low-altitude engine has more power
close to the ground, down where all the strafing and bombing targets
are.

The P-40 was also intended for low level ground support use since in
the late 30's no heavy bomber could threaten the continental US, only
smaller carrier aircraft could get close enough. We were far too
isolationist to spend scarce funds to prepare for major overseas land
operations. Those who knew better counted on several years of
preparation time between the start of a war and serious attacks on the
US. That's why we had battleships and carriers but too few antisub
escorts, which are quicker to build when needed.

Today the F-22 andF-35 suffer the same opposition. It seems we need an
occasional Pearl Harbor or 9/11 to silence the delusion that the world
will be safe if we all think peaceful thoughts. We'll have peace only
when everyone believes they have justice.

Everyone will believe that they have justice when pigs fly (and the pigs
will probably be complaining).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html