P-40F Fuel Consumption?

[downtown]

I took off from Montfaucon to Verdun, according to Google Earth 31.6 KM (about 19 miles) and I noticed my 600L fuel tank gauge dropping as I was flying. From Montfaucon to Verdun I used 100L of fuel, Full throttle, max RPM, no WEP.

America's 100,000 shows the Minimum range of a Fully fueled P-40F at 550 below 8500 ft. no external fuel stores  (54.3 MP/HG at Take Off Power [1300HP/3000RPM Sea Level], 47.2 MP/HG [1150HP/3000RPM 12,000 Ft]  at Military Power and 44.2 MP/HG [1000hp/2600RPM 11,000Ft.] at Normal power.  ( TABLE 32, Page 232 and Graph 27 Page 233)

Just seems to me that 100 liters of fuel consumption is a lot for 19 miles / 32 km.

I don't know if this is a graphics issue (gauge just reading too fast) or the P-40 had three fuel tanks and you're showing consumption from one and at some point it would switch (I've read they used the fuselage tank first, but using too much of it too fast threw off the directional stability) and you'll switch automagically to a full tank.

Edited August 14, 2020 by downtown

[Kidd27]

fly til you run out of fuel, calculate mileage.

Maybe an art issue

[JAMES10]

Hello downtown, how are you?

2 hours ago, downtown said:

...

America's 100,000 shows the Minimum range of a Fully fueled P-40F at 550 below 8500 ft. no external fuel stores  (54.3 MP/HG at Take Off Power [1300HP/3000RPM Sea Level], 47.2 MP/HG [1150HP/3000RPM 12,000 Ft]  at Military Power and 44.2 MP/HG [1000hp/2600RPM 11,000Ft.] at Normal power.  ( TABLE 32, Page 232 and Graph 27 Page 233)

...

I am unable to locate the source referenced but those figures quoted look like Boost Pressures and not Fuel Consumption figures.

Cheers.

[OLDZEKE]

 47.2 MP/HG  and 44.2 MP/HG  I think should be in/HG rather than mp/hg. Manifold pressure US.

 

[downtown]

https://www.abebooks.com/servlet/BookDetailsPL?bi=30487597637&searchurl=kn%3DAmerica%27s%2BHundred-Thousand%2BFrancis%2BDean%26sortby%3D17&cm_sp=snippet-_-srp1-_-image1

If you want I can start looking through the Peter Bower's references, or any of my other books on the P-40.

MP"HG. is how it is listed on the table.

Graph 27 (Page 233) which is Range Miles/Take Off Gross Weight.

The lower line is for P-40E thru P-40M starting at 550 miles to just about 1400 miles  *No Wind, No Allowances for Reserves, 10,000 ft Cruise altitude.

There are two triangles showing the range, the lesser indicating 327 gallons of fuel, the greater is 611 gallons of fuel, so 550ish miles range at 327 gallons and almost 1400 miles range at 611 gallons. (550 miles/327 gallons works out to about 1.6 MPG)

100 liters = 26.4 Gal   

31.6 km =  19.63 miles

26.4/19.63 = 1.34MPG

At the bottom of page 232 is a Note: For the V-1710-39 engine one source gives: Takeoff=1100 HP at 3000RPM at SL at 42.9"MP; Military = 190 HP at 13200ft at 3000RPM at 38.9 HG; Normal 960 HP at 12000ft. at 2600 RPM at 35.0" HG.

So the MP is Manifold Pressure.

 

What I noticed is, that I've never seen the fuel gauge visibly move while flying the P-40 before, yesterday it was visibly moving while flying and it seemed like it was going to go through 600L pretty quick, in like 140 miles, not 550 miles.

[OLDZEKE]

Well that's interesting. While the gauge face does not reflect it, the h87 appears to have a stepped fuel gauge.

I lifted at Calais, gauge dropped to 500 liters at around 45km out. 

I just flew past Overath, last town east of Koln and still have just a tad over 300 liters left.

I've been doing some gauge discovery and this is a neat functionality to find

 

[downtown]

1 hour ago, OLDZEKE said:

Well that's interesting. While the gauge face does not reflect it, the h87 appears to have a stepped fuel gauge.

I lifted at Calais, gauge dropped to 500 liters at around 45km out. 

I just flew past Overath, last town east of Koln and still have just a tad over 300 liters left.

I've been doing some gauge discovery and this is a neat functionality to find

 

Does it change tanks or is it just sucking down fuel?

[OLDZEKE]

Just now, downtown said:

Does it change tanks or is it just sucking down fuel?

Best as I can tell it has 3 tanks.

 

[tater]

Aircraft use fuel in ww2ol? At what scale?

[downtown]

I was going to go to the Training server and test but the only aircraft you can spawn is a JU52M3.

12 hours ago, tater said:

Aircraft use fuel in ww2ol? At what scale?

That is the issue.

[atgman]

Is this the reason I saw lots of pilots in the 2002 era idling (AFK) on the airfield, to reduce the fuel load when going in to combat = less weight?

[Kidd27]

16 minutes ago, atgman said:

Is this the reason I saw lots of pilots in the 2002 era idling (AFK) on the airfield, to reduce the fuel load when going in to combat = less weight?

Fuel consumption has always been. I remember the spit 9 having about 45 min in the air before empty.

and it was quite common practice to use up some fuel to lighten the plane, gaining its benefits. (planes were also common place above 5km)

[BMBM]

Fuel consumption is somewhat generic. Fuel tank capacaties are not. And the P40-F has a floor gauge as well (N, freeview) which I believe I made functional.

[downtown]

I flew Calais, London, Wickenby, Wickenby, London, was on the way back to Calais (disconnect) which would have been about 540ish miles and it looked like there was enough fuel.  Seemed to be a considerable pause on the gauge at 350L.