Something about the p51 I've never understood

[hitech]

Milo The rudder does not control the altitude the Elevator does even if in a bank.

Do a little search on basic flight dynamics , but to put it very simply.

To fly level (not descending not ascending) you need a force = to the weight of the plane in the up direction. I.E. 1g of force.

As you bank the plane the 1g of force that is normally straight up now is some what to the side but also some what up.

The amount of up force in the up direction is the cos of the bank angle * the lift.

Even with out moving the elevator the plane starts to turn, but also descends.

You apply elevator to increase lift in both the direction of the turn until the amount of force straight up is again 1g.

Rudder is used to eliminate any side force on the plane (I.E. ball centered) so that all force is threw your but.

HiTech

[Die Hard]

MiloMorai, in a normal bank turn you don't use rudder to "hold up the nose" like that. You actually rudder into the turn to avoid side-slipping. What you describe is not used except during the so-called "knife edge" where your wings are at or close to 90 degrees on the horizon, but you're not turning then. Unless you're trying to bleed off some speed you're better off leveling the wings a little to get the nose up rather than using the rudder.

[Angus]

Just don't rudder into the turn too much 
Was used as an escape plan. Stall turn, boot on rudder and the aircraft will flip with nose down, let it go, twist and recover.
Evil. 

[Gaston]

    Karnak,

   Sure the Spit Mk XIV had a higher critical altitude than a +25 lbs LF Mk IX, which accounts for SOME of the speed difference. But it was faster at ALL altitudes with basically the same power, so its aerodynamics could not have been worse, especially considering its heavier weight!

   From 67" hg to 80" hg, or 1700 hp to 2000 hp, the V1650-7 engine of the Mustang has NO difference in critical altitude, yet the absolute speed does not increase at all with 300 extra hp, but it does massively so below critical altitude, as does the climb rate. So the top speed is less of a "peak".

  The same thing occurs on the Spit IX. Whatever the reason for this, this is unique to the Merlin P-51 and Spit IX, and completely unlike what happens with most other fighters... Below 25K, an LF Spit IX with +25lbs (2000 hp) will easily beat the climb rate of a 1800 hp Me-109K. In the same way, it will also easily beat the climb rate of the Mk XIV at +18 lbs! Yet at the same time its top speed is about 70 km/h slower than either... If that's not an aerodynamic deficiency, what is?

   A MK VIII with a Gryphon tacked on? How about re-stressed wings, re-stressed engine mounts and fuselage, increased tail lenght and fin surface, and totally re-designed radiators? Compared to all that, Me-109K really is a G-6 with another engine tacked on...

   Diehard, you could be correct that the 109K could use MW-50 with B4 fuel, but earlier 109s could not have the full 1800 hp without combining MW-50 with C-3 fuel.

   MW-50 had many disadvantages; it could not be used in prolonged climbs or prolonged dives without damaging or destroying the engine. This not a good thing for low time pilots... It also increased maintenance and added weight.

   1.98 ata was used only experimentally, or on a trial run basis, in a very few units in 1945; this has been discussed many times already...

   Note that on the 109, full MW-50 power could not be used at prolonged nose-up angles without compromising oil circulation. So it could not add to the sustained climb rate, and it would blow up the engine in prolonged dives...

   That could have something to do with the absence of MW-50 climb rate charts...

   A strong indication of the rarity of MW-50 use in Me-109 units, after the Summer of '44 at least, is the fact that Russians tested their captured Me-109Ks without it. If they didn't use it, why test it?

   While 109s could and did use MW-50 late in the war, "standard" installation does not mean standard use.

   I guess this is a grey area where you choose your leaning...

   Gaston

   

   

 

   

   

   

[MiloMorai]

DB 605 A(M) Standard fighter engine, up to 1475 PS, 605 AM with MW-50 system up to 1800 PS

DB 605 B Same as 605 A but for use in twin-engined aircraft like Messerschmitt Bf 110

DB 605 AS(M) Altitude optimized version of 605 A using the larger DB 603
Daimler-Benz DB 603

DB 605 ASB(M) Altitude optimized late-war version of 605 AS using B4 fuel, ASBM with MW-50 system and up to 1800 PS
   
DB 605 ASC(M) Altitude optimized late-war version of 605 AS using C3 fuel, ASCM with MW-50 system and up to 2000 PS

DB 605 DM First DB 605 D version, standard MW-50 equipment, up to 1700 PS

DB 605 DBM Improved 605 DM, standard MW-50 equipment, first version up to 1850 PS, later reduced to 1800 PS, B4 fuel
   
DB 605 DCM Improved 605 DM, standard MW-50 equipment, up to 2000 PS, C3 fuel

[moot]

Didn't someone post a document showing clearance for a couple of K4 flights (JG54?) for the last months of the war?
http://forum.12oclockhigh.net/showthread.php?t=2470

[MiloMorai]

Didn't someone post a document showing clearance for a couple of K4 flights (JG54?) for the last months of the war?
http://forum.12oclockhigh.net/showthread.php?t=2470

Yes it was for 4 Gruppen with ~150-160 a/c and 60-70 operational.

OKL, Lw.-Führüngstab, Nr. 937/45 gKdos.(op) 20.03.45
 
I. / JG 27 Bf 109 K-4 no change boost increase to 1.98 ata
III. / JG 27 Bf 109 G-10 no change boost increase to 1.98 ata
III. / JG 53 Bf 109 K-4 no change boost increase to 1.98 ata
IV. / JG 53 Bf 109 K-4 no change boost increase to 1.98 ata

Now if you believe Kurfurst, all the a/c were converted but we all know how well he can be trusted. There is also the lack of C3 fuel, which was needed by Fw190 units.

[Nemisis]

How do you take an engine from a lightweight fighter,  (Spit)  put it in a heavier fighter; and turn it into a high performance, long-range fighter?

Well, first off is that the pony has less drag, and high fule capacity. Second is the Pony isn't THAT much bigger. The pony can't climb as well, accelerate as well, and can't turn as well. And remember, the pony is the fastest only at mid alts, not low alts; the drag might have something to do with it.

[R 105]

See Rule #4 (trolling)

[Motherland]

See Rule #4 (trolling)

You keep saying this, yet you have not offered a single shred of evidence to back up your claims.

[Ex-jazz]

You keep saying this, yet you have not offered a single shred of evidence to back up your claims.

Hey just right there! The TV-show said, the P51 won the war! Loser




j/k

[Lusche]

See Rule #4 (trolling)

There is still no fact in this, just an opinion...

[Nemisis]

I say we take a vote.


All that agree with Lusche: (a simply stagering volume of agrement)

All that dissagree *R 105* I do... (cricket chirping)

[Anodizer]

The "under-modeled" theory comes from people watching too much Dogfights...  Reason the P-51 was considered so great during WWII was because pilots flew it to its strengths..  They kept it high and fast, surprise attacks from high above were common and wing man tactics were almost essential.. 
It could fly at speeds where other planes were virtually uncontrollable..  9/10 times, P-51 could dive or zoom away to escape pretty much any attack which, in turn, attributed to it's high survival rate..  This is all how many Pony sticks in the game utilize the P-51..  So, not sure where the whole under-modeled thing is really viable...  I'm sure there is some practically insignificant trivial little thing that anyone could find..  But, for the most part, I think we have a fairly accurate representation of both the B and D Mustangs...

[Widewing]

When the overall drag model was revised, the P-51s took a big hit. A reduction in turn radius and a significant loss of turn rate using flaps was the result. I have tested this against a late version of AH1. Prior to this, the P-51s could out-turn the P-47D-25 and -40. That is no longer the case. Back then, you could dump flaps and maneuver with much of the plane set. That is no longer feasible.

That drag modeling change presented a significant change in drag associated with flaps for numerous fighters. Some suffered badly, such as the Ki-61 as well as the C.202 and C.205. Others saw a huge shift the opposite way. These include the Bf 109s. Other effects were observed. For example, the F4Us became more stable in the roll axis than the F6F-5, which is historically inaccurate. Some improved, some got worse, but the majority didn't change at all.

That said, I'd like to see increased torque effect throughout the plane set. Most are too easy to fly at low speeds.

The reality is that there will never be a perfect correlation to the real world. The level of research required for that is staggering. The volume of data to be sifted through is daunting, and much of it conflicts with other data. I have no doubt that issues will gradually be addressed, but only on a priority basis. Obvious problems are quickly fixed (the P-38 and P-39 flap drag problems were fixed with the next respective patches).

USAAF fighters were engineered for best performance at medium to high altitudes. Most of the action in the MAs occurs at low altitude, under 10k and mostly below 5k.

Down there, the best fighters are those engineered for that realm. For example, below 10k, the P-39Q will slice and dice the Lightnings, Jugs and Mustangs. At 12k, it's as fast as the P-38J and P-47D. The P-39Q out-turns all of these with ease.

Gentlemen, it is what it is. Adapt to it. Adjust your tactics to suit the aircraft. P-51s can not longer stall-fight 109s. So, don't attempt it. Keep it fast, use its superior E-bleed characteristics to maintain a speed advantage or keep it near its corner speed, where it is very effective.


My regards,

Widewing