P-47D-30(Late) Seal Level Top speeds & Wing rack/pylon discussion

[DSR_T-800]

Weather:
Wind = 0m/s(all altitudes and directions)
QNH = 29.92"Hg
Temperature = +20°(20F? or C, I'm assuming its Celsius)

The point of this test was to see if the drag of the pylons was modeled. The answer is, yes.
 

I ended up including the speed difference for over boosting the engine to 72",  which probably equates to 2750 - 2850 hp. If we compare the P-47D-22 with 44-1 fuel/150 Octane) we find that there is a 8mph speed difference between 65" and 70", and this is virtually what we find in game. However, we are going from 64" to 72". I also tried testing the position of the oil cooler and intercooler, and found little to no difference or sometimes an actually increase drag. Specifically with the intercooler in the closed position. The oil cooler - closed, seems to gain a marginal speed boost at the cost of oil temperature going over the defined red line at ~120°C.

Note: The pylons do not alter the weight of the aircraft with their removal or addition.
Note: All speeds are in knots with the conversion to kph in the parentheses

Results:

-Pylons/No Pylons, 100% Fuel @ 142333lbs
299(554)/304(563)

-Overboost
305(565)/310(574)

-No Pylons - Only, 50% Fuel, 50% Guns @ 12760lbs
305(565)
-Overboost
311(576)

The real high speed of the P-47D-30 at sea level is 345mph comparatively to our DCS's 344mph. However, when loading the DCS P-47D-30 to the weight of real life test, we find a 1knot increase in speed. So, its dead on.

I wonder if this was just a ball park estimate for the P-47s pylon drag. I have not been able to find any primary sources on the drag of the P-47s pylons. There are comments here and there with claims of 45mph speed difference on the early razorbacks, and a 15mph difference with the later D blocks. In DCS we are seeing a 7mph speed difference. I don't know which is true, but I think we can agree that speed would slower, and perhaps significantly, because the P-47s wing racks are massive compared to the P-51s. And on the P-51B we see a 8mph speed difference at SL. The P-47 is a much larger aircraft, so proportionally does it approximate to a similar speed lose like we see on the P-51B? Once again, I don't know, and haven't come across a satisfying answer. Here are some approximations I was able to make with the P-47B and P-47D-23 vs P-47D w/wing racks(44-1 Fuel test). We have visual proof of the test plane of the P-47D(44-1 Fuel Test) with wing racks. The P-47B did not have wing racks, and the P-47D-23 from the tactical planning chart specifically states in its remarks that all performance values are shown without the wing racks installed. We also have their speeds at 52"/Military Power at 5000ft.

I was initially surprised to see such a large gap of 23mph. Then the P-47D(44-1) reached parity as the altitude increased. I wonder if this something to do with the temperature difference at higher altitudesnull

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Sources :
nullhttp://www.wwiiaircraftperformance.org/p-47/p47-26167.html
http://www.wwiiaircraftperformance.org/p-47/p-47-tactical-chart.jpg
http://www.wwiiaircraftperformance.org/p-47/P-47B_41-5942_FS-M-19-1523-A.pdf
null

Edited December 10, 2024 by DSR_T-800

[DSR_T-800]

Here is an excerpt from the 56th Fighter Group by Roger A. Freeman.

 null

No specifics of how much performance was lost but it was obviously measurable.

Gabreski's P-47 without wing racks and what looks to be a 215-US gallon tank.