Fokker D VII: Fuel consumption?

[rammjaeger]

In September 1918 every Jasta got only 150 litres fuel per day (claims one source) but I do not know the fuel consumption of the BMW IIIa-Fokker.

What does it mean for a Jasta in service?
How many aircraft could fly how long?

Thanks in advance.

[Barrett]

While I don't know the actual fuel consumption of a D-VII, there's evidence to indicate typical endurance was 90 minutes. 150 liters is about 40 gallons (?) which I'd guess would not top off the tanks of 2 aircraft. This may perhaps explain the exceptional success of the Jasta stars--if you can launch 2 sorties, they'll go to the producers rather than the ho-hum performers or the neophytes.

Hi,Hannes.An average 1950's/60's vintage 4 cylinder 90-100 HP engine normally consumes about 5 gallons of fuel per hour.I would assume that the Fok.D VII engine would consume more,not less fuel per hour.Even at 5 gph,this works out to only about 7-8 hours of flying per day for the entire Jasta.Even in the latter days of the Second World War,fuel deliveries were higher than 150 litres per day(fuel consumption per hour was higher,of course,and in the very last days,there was no flying going on in most Jastas).SURELY the Jastas(especially the D VII ones)were flying more than a total of 5-7 hours per day?!Could the figure be 1500 litres by any chance?Regards.Mukund.

5-7 hours of flying a day for the entire Jasta means a total of ONE 1 1/2 hour sortie for the WHOLE day by FOUR aeroplanes.Evidence on both sides shows that they were flying more than that.Regards.Mukund.

[rammjaeger]

Hi Barrett and Mukund,

this German source is in general reliable but maybe somebody dropped really one number away.

""Für eine Fliegerabteilung standen täglich (=daily) 250 Liter und für eine Jagdstaffel (=Jasta) nur 150 Liter zur Verfügung."

The fuel was given in this rations since September
says "Die deutschen Militärflugzeuge 1910-1918".

Here some data on this from the infamous Kroeschel&stuetzer:

D VII tank capacity: 96 kg (fuel and oil)
Range: 450 km (average)

BMW IIIa:
Usage PS/h: Gasoline: 200g, Oil: 13g
Mercedes IIIa: 226g, 20g

That means:
with 150 liter you could almost fill in two planes to 80% capacity. A Jasta had usually nine planes, which could fly more than one mission/day.

[rammjaeger]

Im Prinzip ja, aber 1 Liter Flugbenzin wiegt sicher nicht 1 Kilogramm (Benzin schwimmt doch auf Wasser oder?), so daß das Treibstoffproblem noch schärfer stehen dürfte.

Danke!

This may not directly apply but I am going to post it anyway:

Bodenschatz lists the number of daily combat flights for JG1 in September 1918, and using my suspect mathematical abilities, I came up with an average of 34 combat flights per day for the 20 days combat flight figures are given for JG1.

Of course this figure is for an entire Jadgeschwader and not merely one Jagdstaffel so maybe divide 34 by four to get a jasta average of about 8 flights per day.

I do not know if there was a standard time length for all combat flights.

This particular JG probably recieved priority in fuel delivery over other units as well.

One should keep in mind that even though a unit may have recieved a limited amount of fuel on a daily basis, on days of inclement weather or little combat the unit may have been able to conserve this daily issue and use it on another day. This may also have depended upon how much discretion the unit commander was allowed in assigning combat flights and keeping (hoarding?)
unused fuel from days with little activity. Indeed, JG1 only lists their combat flight figures for 20 days of the 30 in Sept 1918.

The combat flight figures come from the English
language version of Bodenschatz' book Jagd im Flanderns Himmel.

Regards,

MDD

Hi All!
Don't know if this will help but from the drawings that I have of the Dutch Fokker D7 they show a fuel tank of the following dimensions:
Width: 621 mm
Height: 420 mm
Breadth: 454 mm tapering down to 325 mm.

Hope this helps. Any of you who are of the mathmatical persuasion please feel free to sit down and work out how may litres/gallons this tank can hold. My brain hurts just thinking about it. Lots of luck!
Les

[rammjaeger]

Hi All! I have just found Ezra Bowen stating "every aircraft got 180 litres per day in late summer 1918" (means Jastas) and ammunition became tight. A story about Udet in late August 1918 is following in this book. So 150 litres in September were the next step downward! Hi Les, I thanks for your info but I will not start to compute (because I could miss the new year) and I assume Axel Schudak's number of litres will fit into the tank. The JG1-example of Michael is very useful - why did I not have this idea? Thanks to all! (I leave the net for at least one week maybe more). HAPPY NEW YEAR!