Ju88 prelim fuel use data

[Esme]

Hi! I've been testing the Ju88 for fuel use rate, here's what I found:

Fuel burn rate set to x10
Loadout: 100% fuel, no bombs, altitude = under 100m

                                                                  calculated
MP T-test      T-normal      Speed,kph/mph  range, km/m
52 13:15      132.5mins   400/250     883/552
40 14:13      142.0mins   370/230     876/544
30 19:54      199.0mins   320/200   1061/663
20 27:08      271.0mins   240/150   1085/678

Autotakeoff was used on full power, and MP reduced to required setting as soon as in level flight.  RPM changes made no effect on fuel use rate whatsoever.

That 40MP gives worse fuel economy than 52MP seems odd.  I'd like to request that HTC come up with some kind of generic curve for how MP setting affects fuel use rate, and ditto for RPMs, so that the overall effect is at least more realistic, in a generalised sense, than the current situation. I am well aware that getting correct settings to give precisely correct results for each aircraft would be a non-trivial excercise, hence requesting a generalised implemenation of the effects of MP and RPM settings.

If it helps, I'd happily see the above suggestion applied only to bombers, as it's the kind of thing usually more essential to bombers than to fighters.  At the very least, though, I'd like to see the fuel load of the Ju88 increased to a more realistic amount (maximum range was nearly 1700miles, or a tad under 2700km) and the MP and RPM controls to work sensibly for the Ju88 if also possible.  Please. :-)

As is, the Ju88 in AH appears to have tanks that at maximum are only 1/3 full, but that 1/3 seems to weigh close to the same as a full tank! (I havent got an accurate figure for the weight of fuel carried by the AH Ju88 yet).

Many thanks,

Esme

PS: some day, it'd be lovely to have an auto-dive facility for the Ju88, as per the real thing, too. But that'd just be icing on the cake! :-)

[Wotan]

did you do this test offline? if so to get a more accurate idea of main performance the fuel multiplier is set at 1.5.

Also the main currently has 4 wind layers that are set to 30mph. So planning climb and fuel consumption you may find it useful to match the main in your tests.

Great research btw and I agree on all your points

[funkedup]

Good job Esme.  According to HTC she has 443 gallons internal fuel.  My understanding is that the 1700 mile range figure was achieved with fuel tanks mounted in the bomb bays.  I checked in AH and there are no fuel tanks in the bays.  Also I doubt the 1700 mile figure was achieved at sea level.

[funkedup]

Here's a link: http://www.ophetweb.nl/ww2w/ww2htmls/junkju88.html

Maybe they could add the bomb bay tanks as a loadout option?

[Esme]

Yes, Wotan, I had to do it offline so I could mess with the fuel burn multiplier. I'm not much concerned with the MA performance, as my main interest is in realistic historical scenario play, for the most part.

Funkedup, aye, I KNOW the max range wasnt achieved at sea level, but even so I'm pretty sure that the fuel load isnt right.  The data at the URL given (in Imperial units, yeuchh! :-} ) indicates that whatever type of gallons you're working in, it should be a lot more than 443 gallons onboard.  Yes, it'd be nice to have the bomb-bay tanks as an option.  Main thing is that i a 1:1 scaled terrain, I'd like to be able to fly sorties of the same kind of duration as was done in real life.. like Holland to Liverpool, Norway to Edinburgh.

I'll publish more test data as I collect it.

Esme

PS: Wotan, one should always do these kinds of tests in still air, to  obtain "ideal" performance.  Its a Navigtors job to utilise that data, taking into account prevailing weather, so as to come up with a flight plan that might reasonably be kept to.  KG2 has a couple of good Navigators, as well as some good test pilots :-)

[xHaMmeRx]

Originally posted by Wotan
did you do this test offline? if so to get a more accurate idea of main performance the fuel multiplier is set at 1.5.

Main fuel mutiplier is 2.0 (well, within 15 seconds of 2.0).  Quick test:

Spitfire Mk IX in MA, 25% fuel, flies for 8:50

Spitfire Mk IX off-line, fuel burn rate set to 1.0, flies for 17:56

2 x 8:50 = 17:40

It's off a by about 15 seconds, but close enough to 2.0 for me.

HaMmeR
netAces.org - Info, Tactics, and More!

[funkedup]

Esme:  

If the plane only has 443 gallons then the range you achieved is right on the money, especially considering you were flying at sea level.

From the link above:
"Fuel capacity was 369 Imp gal (443 US gal, 1.675 liters) in four wing tanks, that could be supplemented by an auxiliary tank in the forward weapons bay with a capacity of 150 Imp gal (180 US gal, 680 liters)."

That's for A-1.  I think the A-4 load listed includes the forward bomb bay fuel tank, which I understand was almost always used.  AH has no bomb bay tanks so 443 gal with wing tanks makes sense.

I would get a primary source or at least a published source before I started questioning HTC's fuel load figures.

[funkedup]

This is interesting:  http://rf-hp.npi.msu.su/~vasya/RC/plans/ju88_e.html

PS - I recommend posting a query about Ju 88 fuel capacity in the Aircraft Forum.