tempestglen

I know your site and williams' are "eye for eye".:D 18lbs Spit XIV came into service in Jan. 1944 and while 109K4 at Nov. Is that fair to compare 18lbs Spit XIV with almost one year later's K4? It's unfair to include 1944 Nov-Dec a/c just like 109K4 in "1944 scenario". When was K4 first combat? If an aircraft joined the army in 31st Dec 1944, you still regard it as 1944 plane? OK, "1944 scenario" itself not suitable. We all know from Jan to Oct 1944, there were no combat history of Dora/k4 in Luftwaffe while 25lbs IX and 21 lbs XIV (based in Britain)shot down a Ju88(plus many V1s) and 25lbs Mustang III shot down 14+ German planes. Yes, VEAO team are modeling 21lbs bubble canopy CW Spitfire XIV. When 109K4s came, that was very late 1944 and 1945 spring, so 21lbs Spit XIV, 11-13lbs Tempest MKV, and 25lbs Spit IX are their contemporaneous opponents. http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html

Agree.

950km/h IAS or TAS? If you dive from 11000 m, when you reach 900km/h IAS at 4000m altitude, you are near 1.0Mach(welcome Mig15!). And in il2, Dora isn't torn apart at 900km/h IAS. At 10000m altitude, sonic speed is 1080km/h, ff you can set Dora an initial speed of 620 IAS at 10000m in quick mission, I bet Dora will not be torn apart, however, you are at 1.0 Mach, welcome sonic Dora! In 1943, allied test P51 could dive to 0.76Mach

I've read someone's test in il2 that 1945 Dora could exceed 1.0Mach from ceiling diving. Ridiculous! No air compression/Mach limit at all. Il2 dive FM's already outdated and suitable for low speed diving on east front. It's dive acceleration not roll rate that helped Johnson to beat that ACE spitfire IX. P47 high roll rate just kept it from being locked on by spitfire, the dive acceleration build up energy advantage eventually.

Only if DCS models dive acceleration of various aircraft properly. If they (including third party) ignore the transonic aerodynamics and use simple propeller efficiency curve, I am quite doubt about the reproduce of high speed diving in histoty. I strongly recommend we repeat the test carried in WWII in order to check dive aerodynamics in DCS, if a newbie P47C could not win an experiened 18lbs spitfire IX with "dive extand and pitch back" tactic, ie. to reproduce Johson's story. There must be some flaws in the game.

Robert S. Johnson's story. http://acepilots.com/usaaf_rsj.html Why did Robert S. Johnson suceed? Because his flying style is "wild", high speed dive and zoom, as one of best dive a/c in WWII, P47 can easily engage and break away from luftwaffe. While spitfire IX and bf109G were badly outdived by P47, the fw190 was another victim. P47C/D could dive away from fw190 from as low as 6000 feet (only 1800 m altitude) to the deck.

For a P47C, could easily dive from spitfireIX, extends far away,and zoom up out of spitfireIX shooting range, and fight back using enough energy advantage which is built up during high speed zoom period. And this happens at low altitude, 1 vs 1, boom&zoom, easily solve the spitfire@your 6. Does It sound impossible? Let 's read a funny story. Please note that in 1943 April, the so called "USAAF ace Robert S. Johnson" had ZERO combat experience and merely passed allied standard 500-600 hours flying course(not the shooting score:D). After this famous P47C vs Spitfire IX match, he went to battlefield later and made quite a few mistakes such as losing his team mates, tried to join fw190 formation and flee away, very funny and bold P47 newbie. However, this newbie flied a P47C beat a experienced RAF pilot(A instructor) with 18lbs Spitfire IX who was assigend by RAF to teach the Americans how to air combat in Europe. The faster high speed dive acceleration, the better high speed zoom(not sustained climb). So the Boom&Zoom ability is very important in WWII aircraft comparation. Robert S. Johnson is correct in P47 Boom/Zoom ability evaluation, but he forgot Tempest. My interpretation is below: Let P47C's energy(including both speed and altitude) is Ep. Let Spitfire IX energy is Es. 1) At first, P47C and spitfireIX in formation. So, Ep=Es. Neither are full throttle. Quote: We flew together in formation, and then I decided to see just what this airplane had to its credit. 2) then P47C full throttle to a higher speed, sometime later, spitfire followed with full throttle. There is some distance between p47c and spit because p47 speed up earlier, and p47 has a somewhat higher speed due to higher Vmax. Whether the p47c dives slightly or not is not important because spit is chasing p47c at same altitude with a little lower speed. Now, Ep>Es, only slightly difference. (20-30km/h slower?) Quote: I opened the throttle full and the Thunderbolt forged ahead. A moment later exhaust smoke poured from the Spit as the pilot came after me. He couldn't make it; the big Jug had a definite speed advantage. 3) Quote: The Jug kept pulling away from the Spitfire; Ep>Es, 30-40km/h difference? what are their TAS now? perhaps 600km/h vs 570 km/h? You know it takes quite sometime to accelerate to Vmax in a level flight with full throttle. 4) Quote: suddenly I hauled back on the stick and lifted the nose. The Thunderbolt zoomed upward, soaring into the cloud-flecked sky. I looked out and back; the Spit was straining to match me, and barely able to hold his position. Interesting is that Johnson begin to zoom from a medium speed(Below Vmax), and he found spitfire is in struggle to catch him. So we can say p47c outzoom spitfire: even spitfire could cut the conner, spit could not get closer to a zooming p47c. At this stage, Ep>Es. still slightly advantage. 5) Turning point comes when both speed drops to sth. 300km/h? and below. Zoom period is finished. Continues low speed climb is here. Of course, spit9 outclimb p47c. Finnaly, spit9 fly ahead of and above of p47c and still keeping climb. Certainly, spitfire has opportunity of shooting at p47c at late period of zooming when distant is quite smaller. Now p47c behind of and lower than spit, and spit begin to turn around in low speed, and try to ride on p47c's 6clock again. This stage, spitfire pilot might grin happily. spit9 win! spitfireIX has both angle(before overshoot) and energy: Ep<Es. spitfire's somehow higher energy comes from its better climb rate(25 percent better power loading.) 6) Quote: This was going to be fun. I knew he could turn inside the heavy Thunderbolt;if I attempted to hold a tight turn the Spitfire would slip right inside me.I knew, also, that he could easily outclimb my fighter. I stayed out of those sucker traps. First rule in this kind of a fight: don't fight the way youropponent fights best. No sharp turns; don't climb; keep him at your own level. Johnson is smart, no turn, no low speed climb with a spitfire, otherwise he'll lose. The most important is that the spitfireIX has both angle and energy! and this is at low altitude, only 5000ft. spitfireIX is ready to get to firing position. This is a typical nightmare for those caught by a spitfire at low alt. Quote: We were at 5,000 feet, the Spitfire skidding around hard and coming in on my tail. No use turning; he'd whip right inside me as if I were a truck loaded with cement, and snap out in firing position. Ep=Es, approximately. 7) P47c begin to barrel/scissors with better roll rate. But this could NOT establish energy advantage, just make spitfire not get into firing pisition. Ep=Es, approximately. The distance between them is enlarging due to spitfire's lag in roll maneuver. . Quote: Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our two planes. 8 )Now big time comes, p47c begin to dive, this is the beginning of dive extend/pitch back tactic. If spitfire follows, this will be the beginning of spitfire's failure regardless who is the pilot of spitfire. Even you are the best spitfire pilot in the world, if you dare to follow, you lose, your excellent skills could NOT avoid being out-energy by p47c. Quote: Then I played the trump. The Spitfire was clawing wildly through the air,trying to follow me in a roll, when I dropped the nose. The Thunderbolt howled and ran for earth. Note that p47c begin to dive with roughly same energy with spitfireIX. Ep=Es. Distant between them? Don't know. But it should be greater than the time before barrel/scissors. 9) The dive continues, speed higher and higher, p47c dive acceleration advantage show off. Even spitfireIX has same initial energy, p47c will establish energy advantage during dive. Of course, spitfire could not get closer to p47c, on the contrary, p47c is farer and farer away from spitfireIX.When they reach lowest point of the dive and begin level flight. P47c has more speed, same alt with spit. So, Ep>>Es. and the distance is quite enough for the next maneuver----pitch back. Quote: when I dropped the nose. The Thunderbolt howled and ran for earth. Barely had the Spitfire started to follow—and I was a long way ahead of him by now 10) P47c begin to zoom. This is the second zoom. The first zoom earlier is from not-so-high speed, and p47c get caught by spit. This time is different because p47c zoom from HIGH SPEED after a dive. Spitfire could NOT get closer to p47c even spit could cut the corner, in such a high speed zoom. High Speed is p47c's "secret weapon". Spitfire pilot probably wants to repeat the first zoom, catch p47c when both speed drops to low. But BEFORE that, p47c has already established energy advantage, and spitfire could never get close to p47c, leave alone "overshoot" p47c. Ep>>>Es ! When p47c speed drops to low, at the same time, spitfire IX speed also drops to low. But P47c is quite higher than spitfire, and p47c's altitude is so high that p47c could turn back to spitIX. Amazing. With il2 FB experience we know that p47c should be 500m+ higher than spitfire, otherwise, p47c have no enough space to turn back and spitfire will shoot p47c down. Quote: when I jerked back on the stick and threw the Jug into a zoom climb. In a straight or turning climb, the British ship had theadvantage. But coming out of a dive, there's not a British or a German fighter that can come close to a Thunderbolt rushing upward in a zoom. Before the Spit pilot knew what had happened, I was high above him, the Thunderbolt hammering around. And that was it—for in the next few moments the Spitfire flier was amazed to see a less maneuverable, slower-climbing Thunderbolt rushing straight at him, eight guns pointed ominously at his cockpit. Thus we know Shaw's opinion, P47C establish sufficient energy advantage over spitfireIX by "dive extend/pitch back" tactic. Why? Spitfire is bleeding energy during high speed straight flight---dive and zoom. Spitfire pilot not stupid, he will NOT tight turn while P47c fly straight. Both of them straight fly, but P47c bleeds spitfireIX's energy in straight flight. That's the key. If you are bleeding energy in straight flight, you could do nothing. ACE pilot=rookie pilot during this period. All you should do is to think about how to avoid shot down in the next few minutes by a higher energy opponent.

Allied planes also have elevator trim, could exceed the limit with danger just like 109/190s, so if you compare dive limits. put them in same conditions. Bebore exceeding that 466-500MPH dive limits, 109/190 has already been outdived by P51P47tempy if they begin from cruising speed with roughly same altitude. Many factors involved in Dive acceleration. A 67"(1650HP,18lbs boost, 2.22ATA) P51 can fly as fast as a 1900HP Dora below 4000 m, around 5000m altitude, it's the weaknesss of a two stage superchager while Dora's 1-stage is optiminzed at that altitude. So P51 needs less 200-300 HP to achieve same level speed with Dora. Don't forget a 67" merlin is of 1943 Spring standard of RAF and once P51 ugraded to 1900-2000HP(RAF Mustang III/IV ), Mustang is definetly faster than Dora. When you dive to 800km/h TAS, the propeller efficiency may drops to as low as 60%, air darg/weight are the most important factors and allied had proved Mustang can alomost dive as well as thunderbolt, believed it or not. Dora'd better prepare for being outdived by P47P51tempy in DCS world, this is not il2 series where the air compression(mach number) was ignored and even accurate prop efficiency drop in 700-850km/h TAS is absence.

500MPH IAS is low altitude dive limit for P51 and Tempest/P47. Fw190A's limit is 466MPH=750km/h IAS, around 850-900km/h TAS. Dive to 800km/h TAS is quite common for 1944-45 brand new fighters. As long as you dive within these limit(not steep), you are safe. Spitfire XIV is heavier, more streamlined/powered, than spitfire IX, but the dive acceleration only somewhat better. So will Dora/K4 compared with old versions(fw190A 109G). P51 has extremely low air drag(laminar airfoil) which plays a critical role in high speed dive, P47, that's a brick (5-6 tons);tempest, another 5-ton a/c and well streamlined/polished. These three could easily outdive fw190 in despite of long or short nose.

You are right, but RAF 2nd tactic air force had roughly same quantity of Spitfire XIV and Tempest MKV compared with K4/Dora. Let's forget about overwhelming US fighters.

G10, as few as K4, slightly better dogfight than K4 and inferior max speed/climb, the G10 must has a altitude advantage over Mustang. If same initial energy, when Mustang/Thunderbolt/Tempest dives, they can easily fly away from 109/190 behind.

Don't forget this, LOL. Recently I am very interested in German propeller efficiency at 680-820km/h IAS. You know in that speed spectrum, CSP could NOT maintain steady efficiency any more, all propellers in WWII suffer degraded performance, 10% efficiency difference means 180-200HP. The reason why German sticked to 3-blade propeller is not clear to me, perhaps cannon/gun synchronizer demands it? With regard to speed/climb optimized propellers, it seems that German couldn't have it both ways, someone said: You see, even at 680km or so, the climb optimized propeller increase 15% climb but decrease 4% speed. 4% speed means 8% engine output lose. So if 109K4 equipped with climb optimized props and max. level fly , no 2000HP output at all, only 1840 HP. If k4 dives to 750km/h IAS, worse efficiency. Can I presume K4's efficiency drops more steeply? I am suspicious that German plane data sheet provided by best max speed(with speed optimized props) and best max climb rate(with climb optimized props) at same time, so Luftwaffe pilots need to replace their props in the flight in order to achieve that performance in some games? :music_whistling:

My estimate of Dora/K4 dive acceleration is here, any comment welcomed.

Spitfire IX was an old plane in 1944, its opponents are Bf109G6(ASM), Bf109G14. Don't forget there were no BF109K4/Dora at all in first half year of 1944 and BF109G6/G14 was the majority in Bf109s of Luftwaffe even in 1945. Enrich Hartman ended his service in a Bf109G6 at VE day. :) Bf109K4 around 700s, Dora, again around 700s. not so many. And you should add Spitfire XIV which came into service in 1944 Jan(much earlier than K4/Dora), during second half year of 1944, Spitfire XIV upgraded from 18lbs to 21lbs, i.e. 2.22 ATA to 2.43 ATA with corresponding engine maximum output from 2000HP to 2200HP. VEAO team are developing CW/bubble version Spitfire XIV, this is a nightmare for Dora/K4/Ta152H in 1 vs 1 scenario. For a long time (10 years), Virtual Luftwaffers in simulation, IMO, have been somewhat spoiled by Il2 sturmovic series for the absence of west line most powerful a/c such as Spitfire XIV, 11-13lbs tempy, P47M, they thought K4/Dora (also good planes in my mind) has so called "speed/enregy " advantage to compensate their dogfight inferiority when facing spitfires, the illusion will shattered because DCS is NOT "balance of art", DCS is sniffy about "game balance" while it just wanna reproduce history as accurate as possible. Their philosophy will face the test of unprecedented，a swift Spitfire XIV with K4 clime rate/ speed(especially at high altitude.) So, the line-up of 1944 late "match" is below: 25lbs Spitfire IX vs Bf109G6ASM/G14 Fw190A6A7A8 (majority vs majority, updated old planes) 21lbs Spitfire XIV vs Bf109K4 (minority vs minority, brand new type) 11lbs Tempest MKV vs 1.8ATA(2ATA?) Fw190D9 (minority vs minority, brand new type) :D So RAF do not have to worry about "SPEED" at all when 2nd tactic air force returned to NorthWest europe . The probability of a Spitfire IX was outpaced by a brand new k4/Dora is no more than the probability of a Bf109G6/14 outpaced by Spit XIV Tempy and USA planes. On the contrary, tempy out dives any German piston planes. Drag....Hit and Run....That's the Tempy's favorite. Of course ME262 is much faster, but Spitfire climb rate is 3 times of Me262 at 9000 M altitude and P47M/Tempest MKV are very interested to shoot down a Jet. Maximum level speed has little tactic meaning IF YOU DON'T DIVE FIRSTLY because it takes a long long time for a/c to accelerate from cruising speed to max. speed. However, German planes were badly outlived by P51/P47/ Tempest. http://www.wwiiaircraftperformance.org/sl-wade.html Although Me262 outdives any of them, P47P51Tempy could get it with initial higher altitude.

Korean war! P51(F51) was still very active under the cover of F86.

Postpone Spitfire IX， and add A6 or A8 firstly. My suggestion plane setup is below: flyable plane: P51D P47D 109G6 109A5/6 AI plane:B17 Thus we can reproduce the famous scenario of strategy bomb（1944 early）. Around D day, there was no massive air combat at all. If we have enough budget and time, the second step is to add these below to reproduce air combat in 1944 late: 21lbs boost P51D, 109G6as(m), 25lbs Spitfire IX, 21lbs XIV, Me262, 11lbs Tempest and high boost Dora. Scenario is critical for combat simulation, a serious mission maker will NOT find suitable plane set if we have only 18lbs P51D and 109K4/Dora because DCS P51D is 67" Hg boost =18lbs boost which is seldom in 1944 late and the K4/Dora never appeared in 1944 early sky. Inches of Mercury (" Hg) Pounds of Boost 80.9" of mercury= +25 lb boost 66.6" of mercury= +18 lb boost 60.5" of mercury= +15 lb boost 48.3" of mercury= +9 lb boost 42.2" of mercury= +6 lb boost http://en.wikipedia.org/wiki/Executive_Mustang

The sky without 109G or 190A is NOT 1944 scenario, I am pretty doubt that DCS WWII 1944 could reproduce historical battles, that's to to say, SIMMERs with plenty of historical knowledge may not like this, and the GAMMERs, of course, not either.

I believe there are some serious issues in the Europe 1944, ie Historical precision. No flyable Bf109G or Fw190A8? Are you kidding me? PS, no Spitfire XIV or Tempest either, what a shame!