Spit 14

[Karnak]

I never noticed anything funny about them.  The wing tanks are 11 gallons each as I recall and they drain much faster than the main tanks.

[thrila]

The left tank definately drains fuel 3 times slower than the right.

[Krusty]

By god, I never frakking noticed this!!!!

Did a little testing offline. The tank labeled "LW" has 45 gals; the tank labeled "RW" has 15 gals; the tank labeled "NU" has 15 gals; the tank labeled "Main" has 58 gals.

Cranked fuel burn to 10000, manually selected a tank while sitting on runway, started engine and it sputtered dry before I rolled. Check E6B readout to get gallons (rounded to nearest gallon).

I'll try a test in a few minutes to see if I can trim for level flight, drain "LW" and see if I start rolling right or if I stay level.

That will tell us if the labels are simply wrong, or if the tanks themselves have been placed in the wrong place on the flight model.

[SirLoin]

How to fly it ?..It's the ultimate rope plane.Don't let the nme see the 14 icon,try and blend in like a normal spit and set up a death rope..and at the top flip her over to the right,not left because of the tourque and hit flaps.Werks evrytime.

[Krusty]

Okay, I took off with 0 fuel burn, leveled off, throttled back a bit (so as not to fight torque so badly) and trimmed for level flight as best I could, doing around 270-270 IAS at 4k.

Manually selected left wing tank, pulled up arena settings, set drain to 50x, let it empty the tank and entered "0" and hit "okay" as soon as the fuel was gone, switched tanks really quick to restart motor. The intent was to not lose forward speed, and to get the prop going again so the torque was already trimmed for.

I started rolling noticably to the right after draining the "LW" tank. The only thing that stabilized this was to repeat the process with the "RW" tank.

So it's not a matter of mis-labeled tanks, it's a matter of the tanks being wrong, but in the right places. This definitely could be a major reason the spit14 has been unstable. Also the left wing tank drains first, which at first wouldn't be too bad, but as it has almost 40% of the total fuel in it, the weight loss makes the balance of the plane fight against torque.

[Yarbles]

Okay, I took off with 0 fuel burn, leveled off, throttled back a bit (so as not to fight torque so badly) and trimmed for level flight as best I could, doing around 270-270 IAS at 4k.

Manually selected left wing tank, pulled up arena settings, set drain to 50x, let it empty the tank and entered "0" and hit "okay" as soon as the fuel was gone, switched tanks really quick to restart motor. The intent was to not lose forward speed, and to get the prop going again so the torque was already trimmed for.

I started rolling noticably to the right after draining the "LW" tank. The only thing that stabilized this was to repeat the process with the "RW" tank.

So it's not a matter of mis-labeled tanks, it's a matter of the tanks being wrong, but in the right places. This definitely could be a major reason the spit14 has been unstable. Also the left wing tank drains first, which at first wouldn't be too bad, but as it has almost 40% of the total fuel in it, the weight loss makes the balance of the plane fight against torque.

Can we get HTC to fix this???

[RTHolmes]

Did a little testing offline. The tank labeled "LW" has 45 gals; the tank labeled "RW" has 15 gals; the tank labeled "NU" has 15 gals; the tank labeled "Main" has 58 gals.

wow well spotted   always wondered why the "NU" tank drains so much faster than the wing tanks. and indeed what "NU" stands for

[thrila]

I can't believe none of us noticed this years ago.   just goes to show how observent we are.   


Nice work krusty, i wasn't sure if the LW and NU tank were simply mislabelled or physically swapped in the model.

[SirLoin]

Wouldn't the right tank being smaller in capacity..aide in stability?Remember the tourque is opposite in spit14...



So the wise thing would be to drain right tank first.Auto select fuel burn should work the right side first after the DT is empty otherwise it is making the plane unstable by burning left first.

[Krusty]

That's why I pointed out before that the spit14 "auto" burns the left wing first. The odd part was that even though the left wing has 3x as much gallons in it, it didn't weigh much more than the right tank. That is, at least, it didn't cause more rolling than the right wing. Emptying both left the plane neutrally trimmed.

I first drained "LW" to get the roll towards the right going. On a hunch I burned off "NU" next, but my conclussion is that it is located in the fuselage, because it did not affect roll. I then drained "RW" and after that was empty and I was back on my last tank ("Main"), the roll was balanced out and I could take my hand off the stick with almost no roll. It was back where I had originally trimmed it.

So left and right wings balance each other out, but the damage is reversed, and the left holds way more gas (but not 3x as roll from the gas weight???)

[Yarbles]

So left and right wings balance each other out, but the damage is reversed, and the left holds way more gas (but not 3x as roll from the gas weight???)

So could you simply explain what effect if any the 3x right left wing fuel tank has on performance?

[Rebel]

I would assume that roll rate would be drastically affected, as would low speed maneuvering/stability with that much more fuel on one side then the other.  That would shift the CoG dangerously out to one side, I'd think.

[Yarbles]

I would assume that roll rate would be drastically affected, as would low speed maneuvering/stability with that much more fuel on one side then the other.  That would shift the CoG dangerously out to one side, I'd think.

Agreed but I think I am deducing that the fuel but not the weight is in the left Wing and so the vrtual world loses touch with reality here.

In this case I assume appart from having to burn too much of the overall fuel to get the wings empty no other effect effect. 

[Rebel]

Only person who can really answer that with any kind of certainty is hitech.

I'd be surprised if he put twice as much gas in one wing then the other and not had the mass computed at the same time. Not saying Krusty's tests are invalid, nor am I saying that was the design spec of the a/c- I simply don't know.   But I can bet that if you tell a computer a wonky value like that, it could DEFINITELY explain some of the Spit XIV's quirks. 

From what I understand, you're saying that even though the game says there's a huge amount of gas in the left wing as opposed to the right wing, but the weights are acting as if they are equal, and therefore cancel each other out.   Is this correct?

[gyrene81]

I wonder if anyone has seen any written accounts of its performance. 

Perhaps if we had some data we could get Hi Tech to re work it a bit. At the moment we have high perks and crap handling or the worst of both worlds. I would say remove the perk or take the rough edge of it. It cant be both a perked ride and bagger to fly. Dont make sense

Sorry to chime in late on this. I noticed the focus of conversation has moved to the fuel tanks but here ya go:

http://www.spitfireperformance.com/spitfire-XIV.html

http://www.spitfireperformance.com/rb141handling.html

http://www.spitfireperformance.com/spit14afdu.html

http://www.spitfireperformance.com/109gtacvspit14.html

http://www.wwiiaircraftperformance.org/

Pretty much any data you want (performance wise) from actual historical documentation. Someone in that last link are some after action reports from actual P51 pilots.