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Puting the DB-603 supercharger on the DB-605 from the start (ie starting production with both A and AS models in parallel) in 1943 would have been a big enough deal on its own. Or even considering larger/high alt supercharging on the late model 601s. That's probably more important than intercooling, water injection, or 2-stage developments.That hammers home one thing - a timely 2-stage DB 605 would've been a major boon for the Axis, at least on short term.
Given the mustangs were mostly powered by Merlin 61 and somewhat lower alt optimized 66 equivalents, the performance of the 70 series isn't quite as relevant ... or at least necessary to match/beat. (and the fact the Mustang featured a mix of engines like that points to the better high alt performance envelope of the 61 still not being worthwhile enough to sacrifice power down low)Big supercharger really boosted the performance of the DB 605 line, bringing the hi-alt power to the level of 2-stage Merlin (though the 70 series was still the king of hi-alt). The MW-50 helped with low- and mid-alt power since it allowed for much increased boost. The inter-cooler, with or without conjunction with MW 50, would also come in handy.
If nothing else, they should have been experimenting with larger/higher alt optimized supercharger arrangements on the 601 line itself, before the transition to the 605. (higher alt tuned 211s would have been useful too, but given most applications it was adopted for, there's less express incentive for that over focusing on the 213 ... compared to say, if something like the Fw 187 had adopted the 211)In a thread that was here some months ago, I've suggested using the DB-601E as a basis for new engines with following improvements (some can be used together, some cannot): big supercharger from DB 603A (for 1943), intercooler (for late 1942), 2-stage S/C (late 1943), increase in RPM to 2800 (like the 601N and eventually 605; in 1943), MW 50 (winter of 1943/44).
The S/C of the 601E was 260mm diameter, 75% efficient, 363 m/s tip sped; for 603A respective values were: 295mm, 77% and 378 m/s.
Given the mustangs were mostly powered by Merlin 61 and somewhat lower alt optimized 66 equivalents, the performance of the 70 series isn't quite as relevant ... or at least necessary to match/beat. (and the fact the Mustang featured a mix of engines like that points to the better high alt performance envelope of the 61 still not being worthwhile enough to sacrifice power down low)
If nothing else, they should have been experimenting with larger/higher alt optimized supercharger arrangements on the 601 line itself, before the transition to the 605. (higher alt tuned 211s would have been useful too, but given most applications it was adopted for, there's less express incentive for that over focusing on the 213 ... compared to say, if something like the Fw 187 had adopted the 211)
Given the mustangs were mostly powered by Merlin 61 and somewhat lower alt optimized 66 equivalents, the performance of the 70 series isn't quite as relevant ... or at least necessary to match/beat. (and the fact the Mustang featured a mix of engines like that points to the better high alt performance envelope of the 61 still not being worthwhile enough to sacrifice power down low)
211 seems like it was always a supplemental engine ... not the best in any class, but produced in large numbers and more reliable and easier to maintain at times. But yes ... bombers, transports and other aircraft that don't need the likes of the 801 would make the most sense there. (4-engine bombers using 211s would have been useful ... had they been developed -the few 4-engine heavy bomber/transport aircraft that did appear were a bit too large for the 211 to work on ... and lack of a more modern replacement for 2/3 engine transports like the Ju-52 -I wonder if the He-111 would have handled reasonably well adapted into the dedicated transport role)The sooner Jumo gets the 213 in production, the better chances are for the LW pilots in 1944 (of course, bolt the 213s on the Fw 190s). With fully working BMW 801D, DB 605A/603A and availablity of Jumo 213A from late 1943 on, there is no much appeal on the 'fighter version' of the Jumo 211.
It's the 1650-3 powered aircraft that showed the more noticeable high-alt performance edge over the contemporary 190As or DB-605AS/ASM (or DB-603A). The 1650-7 powered Mustangs would be tuned more into the optimal performance range of the existing German designs, if not a bit lower in the case of the 605 AS and Jumo 213.The P-51B/Cs were almost equally split between the V-1650-3 (1950) and V-1650-7 (1790) engines.
With the introduction of the P-51C-5-NT onto the Dallas production line and the P-51B-15-NA in the Inglewood production line, the Packard V-1560-7 engine was adopted as standard.
All P-51D/Ks used the V-1650-7 (9600) engine.
Yes, that was kind of my point a while back regarding (in practical operational terms) the somewhat lower critical altitude tuning of the -7 fit the useful performance envelope for needed power better. Service ceiling was still plenty high, and cruise performance was fine up high, but the peak power was a bit lower down. (where it was more often most useful)The -7 P-51D could get to over 41,000 feet, and if they had a "high cover" force, it had 500+ miles to get that high at cruise speed and, if there WAS a need and a mission element for P-51D's to get way up high, then they were probably there when they needed to be there. Any combat at 35,000+ feet in WWII was a 2.8 - 3.1 g thing that went downhill very fast. There were no hard breaks or the hard-breaking pilot would stall and fall several miles before recovering. About all they could do was to make gentle turns or a roll and dive. They surely weren't doing much climbing fighting, Lufbrey circling, or "dogfighting" at those altitudes.
Yes. It seems the "high altitude war" in th ETO gradually worked its way downward as accuracy became more important than high-altitude bombing did.
The P-51's needed to be tuned to the actual bombing altitude of the 1,000-plane raids, not the Luftwaffe's top fighters. Their job as escort was to protect the bombers, not get higher than the highest German fighters. If the Luftwaffe was diving through the formation, they were already higher and enough P-51's had to STAY with the bombers so they would not be abandoned to what German fighters were left.
Mostly true Greg - but typical escort altitude for 1st and 3rd Division B-17s was 28-30K for high cover, with the other two squadrons in an escort group at different locations by directives of CO
The -3 or -7 didn't matter much to the mission, just to individual fighter vs. fighter situations.
It made some difference to those fighters in the 'high altitude' escort station.
The -7 P-51D could get to over 41,000 feet, and if they had a "high cover" force, it had 500+ miles to get that high at cruise speed and, if there WAS a need and a mission element for P-51D's to get way up high, then they were probably there when they needed to be there. Any combat at 35,000+ feet in WWII was a 2.8 - 3.1 g thing that went downhill very fast. There were no hard breaks or the hard-breaking pilot would stall and fall several miles before recovering. About all they could do was to make gentle turns or a roll and dive. They surely weren't doing much climbing fighting, Lufbrey circling, or "dogfighting" at those altitudes.
Throughout 1944 the 8th Air Force bombed from ever higher altitudes. Statistics from the 8th AF's ORS support this.
Maybe the fact that in the September to December 1944 period a large majority of US bombing was done on H2X through cloud, with very low accuracy, only 1 bomb in 500 landing within 1000' of the target and an average circular error of 2.6 miles, had something to do with a failure to reduce the bombing altitudes. This was also the end of the ludicrous pretence by some American commanders that they were precision bombing.
Steve
If a major threat had materialized in that altitude range, the XP-38K and XP-47J would have likely seen more interest due both to the added all-around performance and particularly their high service ceilings. For either to be really practical, they'd need to have dive recovery flaps fitted given how close to critical mach they'd be at high altitude.Good question,Shortround.
Had the Germans gotten into very high altitude capabilitiers, my question would be whether to ignore them and bomb from 20 - 25,000 feet anyway or have the escorts we had anyway but develop dedicated high-altitude engines for the high-cover mission aircraft. Likely they would have developed the high-altitude capability and I'm thinking supercharger - turbocharger combination since that is what we did hsitorically in the P-38 and P-47.
The problem with saying the Americans is inaccurate in daylight high altitude bombing is in the understanding of the data. When a computing bombsight was used it could be deadly accurate, good enough to hit a moving ship with a stick of bombs.
Systems such as Micro-H and Gee-H could control perhaps 50 bombers at once and guide them to better than 100 yards though the bombs spread over 20 times that distance. One opperations report has Micro-H spreading its bombs over 5 MILES.