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It's pretty understandable that wing/fuselage pylons reduce maximum attainable level speed but I was wondering if they affect the maximum climb rate too? I'm thinking they might but not understanding the properties of lift vs drag in a climb situation I'm wondering if it's very noticeable at the optimum climb speed for a particular aircraft?
Yes, as they increase drag, which increases the power required at any speed, which reduces the power available for climb.
Well the pylons must have some effect but they hold bombs and tanks that the aircraft takes off with so not that much. I think they knocked 10-20 MPH off the top speed.Thank you swampy, I just wanted to make sure that the extra drag could have a noticeable effect on climb and now I know that it does.
Well the pylons must have some effect but they hold bombs and tanks that the aircraft takes off with so not that much. I think they knocked 10-20 MPH off the top speed.
wwiiaircraftperformance.org shows bomb racks for the 109 to reduce speed by 0-2mph, but underwing guns reduce speed by 7mph. Underwing bombs reduced speed 4mph. There is a climb graph but the tropical sand filter is also included so it would be hard to compare with the clean 109.
The racks only reducing speed 0-2mph seems like a stretch since the P-51 racks cost 15mph. And two underwing bombs only cost the 109 4mph. That must be one really clean installation.
A P-47 with 3 pylons/racks might see a rather larger difference.
The test data that I've seen of two different P-47Ds suggests around 300 fpm initially but the climb rates become much closer after an altitude of 16,000 feet is reached (when looking at 65" Hg of engine boost). The two aircraft had identical propellers and were ballasted at roughly the same weight (13,230 lbs vs. 13,260 lbs), with one in clean condition and the other with two wing pylons:
P-47 Performance Tests
http://www.wwiiaircraftperformance.org/p-47/p-47d-75035-fig2.jpg
http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-climb.jpg
Totally agreePractically all aspects of aircraft performance are a function of the operative ratio of lift over drag at any given moment in any given maneuver, as that determines how much power is required to continue the maneuver. When power required increases to match power available, you've reached the limits of performance.
I was a 1500 hour flight instructor, parroting this info to my students without intuitively understanding it, when I became a glider pilot, and true understanding dawned.
If you ever take up flying, I suggest you start with gliders. That's what Capt Sullenberger did, and look what it did for him. (Miracle on the Hudson, if by some slim chance you didn't know.)
Cheers,
Wes
Air density affects all the variables of aircraft performance, and the differences with altitude are not linear, and will affect different performance aspects in different ways. A particular supercharger / turbocharger installation will not necessarily drive engine power in a linear relationship to ambient air density. A propeller won't convert horsepower to thrust at the same efficiency level at all air densities. We haven't even got into lift or drag yet. Get the picture?Question: why is there larger differences in the climb rate between the two airplanes at lower altitudes? Wouldn't there be be similar differences at most altitudes, with both airplanes climbing at what was deemed the P-47's optimum climb speed?
A particular supercharger / turbocharger installation will not necessarily drive engine power in a linear relationship to ambient air density