Question about the -51D center tank

[Dune]

Hiya guys!  I'm taking HT up on his free two-week offer and looking around.  

Well anyways, I was looking at the write-up on the -51D at the AH webpage.  There it mentions the center tank throwing off the CofG if it's full.  All very historical of course, but my question is this:  The webpage says to drain the tank completely.  However all the books I've read and my grandfather (flew 60+ combat missions in the -51D) all say that by draining approx. 30% of the fuel you can move the CofG back up to where it's supposed to be.

So, is the -51D in AH modeled in a way that you have to drain it all to move the CofG or will around 30% do the trick?  (Not a complaint/squeak/etc. about the model, just a gameplay question)

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Lt Col Dune
X.O. 352nd Fighter Group
"The Blue Nosed Bastards of Bodney"

"Credo quia absurdum est." (I believe it because it is unreasonable)
- The motto of the Republic of Baja Arizona

[RAM]

Ummm well I dont know...

What I can tell you ,DUne is that with 75% fuel and drop tanks in P51 you can go around the map twice and still have fuel for a long fight.

No real need to load 100% fuel...and with 75% the AUX center tank only is loaded with 25% fuel...

[Vermillion]

Dune, the tank your talking about is the "Aux" tank in AH.

If you only load 75% or less fuel, this tank isn't filled, so its not usually a problem.

I fly the Pony alot and I find the best fuel strategy is to load 50% internal fuel, along with two drop tanks.

On climbout, drop one tank, and use the other to climb to altitude, and to get to the combat zone.

The 50% internal fuel is more than enough to fight till you exhaust your ammo, and then plenty to get home with.

If you do decide to load 100% internal fuel, just use the SHFT-F key to change your fuel gauge to read "Aux" to drain off however much fuel you want out of that tank.

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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"

[Sharky]

Hiya Dune,

Dune I can tell you from at least one experiance that yes the modeling of the CG shift is correct when the fuesalage tank is filled  

Now I don't know that using 30-40% of the fuel in that tank is enough to move the CG back to within spec.  After my first experance with the CG shift I have avoided filling that tank like the plaque  

If ya take the time to test it could ya post the results?

Sharky
P.S. Dune I'm a trainer here and I know you don't need training on flying the pony, but if you would like a "walking tour" of AH lemme know and we'll get together.  I gave daddy= one of these, ya know the differances, how this and that works.  Just to save you some time.
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Playboy Leader
307th FS/31st FG
You can run but ya just die tired

[This message has been edited by Sharky (edited 06-09-2000).]

[juzz]

(Un)fortunately stability isn't modelled, otherwise it would be a real pain to fly a fully fuelled P-51D.

Eg: This quote is about a Spitfire Mk IX with a 70 gallon rear fuselage tank, but the situation was similar for the P-51D.
 

Longitudinal instability started when a speed of 140mph was reached and as speed increased so pitching was more pronounced. When flaps and undercarriage were lowered pitching tended to disappear. During climb conditions the pilot had to fly the aircraft all the time for the control column could not be released or grip slackened without a divergence of course. At fast cruising, 245mph at 12,000ft, it was necessary to use the control stick continously to damp out pitching and the aircraft could not be trimmed. In steep turns acceleration increased rapidly and a moderate push force was needed to prevent build up. If the push was overdone negative "G" was experienced and pull had to be applied. After 35 gallons of fuel from the rear tank was used the aircraft stabilised.

Q: Do people want nasty characteristics like those modelled?

[funked]

Juzz, you are citing a case of undamped oscillation.

The P-51D in our game does have some underdamped directional oscillation when the fuselage tank is full.  It is a real pain in the bellybutton to aim in that condition.

[juzz]

"underdamped directional oscillation" aka "nose bounce" ???

[funked]

Precisely, except it's a directional (yaw) motion.  The plane has it's highest inertia and lowest damping about the yaw axis.  There is a reason most US fighters had dorsal fillets and vertical stabilizer enlargements.  

[juzz]

Hmmm, I really can't tell any difference between 100% and 25% fuel in the Mustang... If I momentarily input full rudder at low speeds/high power, it seems to react the same way with both fuel loads.