posted on Jan, 24 2006 @ 09:33 AM
First, a 'paraquote'...
Pg. 26 of Monogram's Close Up #24 on the Ta-152 (Hohenjager in this case) states that a test flight out of Cottbus took the 152 up to 43,290ft and
did a speed run which was later worked out with the aid of onboard recording instruments and a test pilot in the as 508 to 515mph ground speed.
Now, some much needed 'it depends' qualifiers.
1. Airspeed is usually lower than ground speed because pitot's (particularly of this era) were tuned within a given altitude band and as Mach
number, potential icing and density altitude built up or bled down, they showed a HUGE range of needle-on-the-dial-says numbers. Remember too that
565 knots (Mach 1) at 36,000ft is nearly 650mph. This is why I trust the Focke Wulf quotes because while nearly everyone has a crotch grabbing moment
when it comes to stating figures for 'their' national-best preferred airplane, the preproduction Tanks had primitive 'variometer' (acceleration
gyros) and a wound-paper barograph onboard to meet late war RLM as well as Tank criteria for performance validation.
2. Almost all aircraft had quirks of performance change, some quite large, even between models. The P-51B/C were 450mph machines, while the P-51D/K
with the bubble canopy (more aft fuselage airflow breakup) and more weight were slower, 'officially' around 437mph. Real speeds could vary even
more because things like plugs and tunes and turbo settings as well as good skin condition (minimal dings and patches, no unplugged A2G mods,
excellent maintenance of waxed polish NM, _no paint_) all played a part in friction drag as well as induced (wingloading).
3. Almost all German latewar aircraft used either a high or low octane fuel with a booster factored additive performance margin. Without the MW-50
(methanol water) or GM-1 (nitrous) the Me-109G6 was barely a (396) 400mph class fighter, despite having a /monster/ HP to airframe empty weight
margin. With the additive you had aircraft wich would easily top 428mph (G14AS/G-10, 454mph in the K) and climb at almost 3,8000fpm. The problem
being that the additives also had severely (eats cylinder) deleterious effects on the overall engine compression and could be used only in short
bursts with no real 'on off' ability. That the various hi-low altitude and octane rated DB-601 and 605 engines could accomodate all this abuse and
modification was one of the marks which made the engine more than the airframe the hallmark of Augsburg's Eagle.
By the same metric, we had tetraethyllead compounds (in open literature throughout the later 1930s, amazingly enough) which eventually ended up giving
us as much as 120-150 octane fuel ratings where the Germans were lucky to bust a hundred. Coupled to a working turbosection (magnesium and titanium
hotduct metallurgy that didn't light off at multiple hundred degree temps higher than the Germans could work with) and mechanical superchargers with
automatic staging, we were gifted with upwards of 15-20 minutes of usage (and repeat usage after a cooldown, provided you had the gas and the engine
wasn't rough with all the lead on the plugs). Allowing us to get more reliable (flat power:altitude curve) and less dangerous (no frozen MW
'slush' clogging the lines or exploding in the cylinder) head pressure performance from our engines.
4. The P-47M and indeed all P-47s were rather better high altitude machines than are given credit, considering the P-51 was basically a cruise-only
'laminar for the first third bird'. They had fantastic roll rates and superb acceleration at speed (both mechanical and turbo paths AND lightning
water chugging enriched air to the engine). They even had a better performance in the dive where, even though their absolute limiter number was not
quite as high as the Mustang, their elevator and aileron performance plus overall mass made them more steady (less porpoised) in the buildup. It was
not P-51's that were a threat to the Me-262's attacking the bomber streams, late war. It was top cover P-47s which, with a little unload, could
actually run down at least the R4m equipped birds, _from behind_ (a German will tell you this is because of coaltar fuel and novice pilots
'compressed' by jet speeds, throttling back to make firing passes.).
5. VNE is _very_ important. And one of the reasons I laugh at the stupidity of even a test pilot 'trying to pull the wings off in a dive'.
Because he won't bail out and if he hits a 600mph windstream as his plane comes apart, so will he. Literally, that is what Mach tuck does on a
straight wing aircraft with fighter section airfoils. It pulls you down deeper and steeper until the Mach buzzz shakes you apart. That same Ta-152
I quoted has a maximum airspeed before before the long, single+half spar wings literally flex the airframe apart of only 498mph. Thus there is no
real point to having an ultra high maximum level airspeed if it is unexploitable due to remaining margin under maneuvering or dive loads. For while
nobody will bother you at 40,000+ft, when you go to stoop down on the bombers at 25,000, you're //finished// if you don't have a speed brake.
6. No aircraft NOT ABLE TO PERFORM THE MISSION at the moment of maximum speed achievement. Whether it was started out as a speed prototype. Or was
rendered into one. Can be considered a 'fighter'.
Rare Bear in particular has an engine with almost double the HP of the wartime variant, a reprofiled back end and a propellor off a plane (Skyraider)
twice it's original chord for roughly the same blade length. It's wingspan is clipped and it also is running on something closer to a top fuel
dragster's octane than anything we could make (lead and all) octane-equivalent back in WWII.
And I still bet it is a pig (too rich for the available aspiration, monster wingloading) at altitude.
7. Tactically, speed is useful. But only as a function of avoiding combat or presetting the conditions of entry into it. The dictates of physics
and formation geometry require that you fly significantly slower and wider that potentially possible if you want to keep wingie tucked in and covering
your cone. At which point, coordination between the pilots and good _transient_ (acceleration and roll rate/stop/reversal) performance become much
more critical in regaining a midrange 'fighting speed' after bleeding down in deliberately short, sharp, saddling maneuvers (turn to shoot, never to
G-suits were also not universally available to allow sustained high-G performance and in any case, /airframe/ rated turns were usually best sustained
in the region 250-270 knots, higher meant increasingly hard controls and chances of accelerative stall.
Indeed, if there is a point to maximum speed in a 'slowest soldier sets the march' sense of wartime aircraft performance and tactical conditions; it
is simply that of getting away from basing mode predictors quickly, getting to height reliably (good angle of climb angle, sustained power levels).
And getting away from the fight once you have made your 1 Pass Haul Hindquarters attack.
Because these are the merits by which you are not 'swept' by lead fighters where you are most predictable/vulnerable (near the airfield or in the
marshal stack). Able to be responsive to the GCI controllers in steering early to bearing, not height on the best raid cutoff angles. And able to
separate cleanly from any fight which you cannot win except by surviving to do it again tomorrow.
In some ground attack aircraft (notably the Ar-234) and certainly in reccers it is also important to have speed in the pass through the target area
terminal defenses and as a slight turnaway or altitude climb reserve against manned intercept and radar fuzed flak. But even here, you are looking at
_very_ specialized profiles compared to the majority of conditions where sighting systems and weapon ballistics (as well as target acquisition and
aiming cycle limits on human biology) just _do not_ support the 'fast pass' approach to either static interdiction or particularly mobile target
(CAS) work. As well as driftsight compensation for photowork.
The Russians in particular discovered with the Il-2 that one slow approach that scored maximum damage from a long, slow, approach did more to instill
shock and suppress defenses than any subsequent 'numbered attack' with high speed aircraft or multiple formations.
In fighter ops much the same rule applies except that your tail on closure margin is lower against a cospeed target while your sights (fixed stadia
vs. gyro) and training (deflection shooting vs. closure to cone) usually dictates more of the survivability as much as lethality factor in anything
but low angle off headon alternatives. In any case, you are better off getting one shot off from close range and then speeding away 'from the side
that doesn't shoot back' than trying to use slashing (energy) or maneuver (angles) combat to 'mix it up' with the enemy formation as a whole. You
just waste gas and lose people randomly daisy chained or unseen-shootered that way.
I like the Ta-152 as probably my favorite looking late war fighter. But given any one aircraft, by period and theater, I would probably pick the
P-40, Hellcat, Lightning, Hog or TBolt as my principle types for Early CBO/PTO, Midwar PTO/MTO, Late PTO and Late ETO. Because they have the mix of
hardiness, firepower, horsepower and some element of _useful_ controls as much as airspeed margin over their opponents to be tactically dominating
through the ease with which they could be exploited.
At the same time I would readily admit that this is as much a circumstantially factored condition relative to the timeframe as anything in each
airframe or model variant. An Me-109F could hand almost any P-40 model driver's head to him, and did, repeatedly, in the 1942 Desert as well as the
Russian Front. Only a Hurricane was worse off. A 109F was relatively easy meat for a P-51D or Spitfire IX. But it was a harder kill at medium
altitudes than a 109G in many respects.
A Lightning was no match for a well flown 190 at low altitude but could show up in places where it was utterly unexpected by 109F/Gtrop pilots who
were operating a clapped-engine machine over the Med that could not outaccelerate the twin as was their Northern European wont, below 15,000ft (where
the P-38G/H had full HP).
A Corsair would be completely (manual engine/flight controls) overmatched by similar speed range, vastly more agile and equally well armored Euro
opponents from the midwar on. But it was simply a good gun and energy (BnZ) platform for the largely