Late war fighter competition

[drgondog]

here is the SAC pilot handbook data for all versions of the 51H - published in 1949.

Looks like the interceptor version (full internal fuel, no tanks) got to 25K in 6.7 minutes with 3200 fpm climb rate left. 8-8.5+ minutes to 30K might be about right. Top speed = 411kts at 25K ~ 473mph.

Notice the climb rate loaded at 9845 (all internal fuel) at SL/25K = 4990/3200 fpm but when flying 'light' the maximum climb rate is 5850/3450fpm for SL/25K respectively. (Note: column "II" with GW = 8283 looks like it should be under column "III")

So, the climb rate for light configuration (8283 lbs) should get it to 30K in less than 8 minutes.

 

[Soren]

All the performance figures for the Ta-152H are with a fuel load of 594 Liters of B4 fuel (Fighter configuration). With a full fuel load of 1109 Liters as used for long range reconnaissance or escort duties the weight was 5,220 kg.

Time to climb to 32,800 ft was 10.1 min for the Jumo 213E powered Ta-152H. The take off run was a mere 295 meters. With an extra 450 hp I suspect a time of 7.5 min to 10 km and a 245 m take off run.

According to this chart (http://www.wwiiaircraftperformance.org/mustang/p-51h-booklet-pg15.jpg) it took the P-51H ~9.5 min to reach 32,500 ft at 90" Hg. Question is then, when was the P-51H ready to be run at that power? 1947 ?

 

[vanir]

Soren, I hope I do not offend by mentioning my impressions taken from recent publication (that feller on the LEMB forum occasionally that published the Ta152 book everybody raves about), are quite the opposite according to the quoted pilots and various primary references therein. According to memory (I've the excerpts on my hdd somewhere):

Firstly it was most likely the Ta152H was to be re-engined with the Daimler motor, and this was the recommendation following service trials. There are several reasons for this.

Firstly Kurt Tank was the only pilot who managed to exceed 12.5km altitude with the Jumo, the other pilots said it wasn't possible and brought into question his claims of ca.760km/h at the 14km absolute ceiling. The actual service ceiling is cited as 10.5km primarily due to unreliable operation of the cockpit pressurisation system and extreme intake temperatures (causing unbearable cockpit temperatures).

The few flights made to 12km and higher nearly killed the pilot, one passed out and didn't regain consciousness until below 5000 metres, though he was amazed the a/c was still flying controllably and remarked on its totally amazing stability in a power on dive. The critical altitude of the Jumo engine is actually around 9.2km and there were problems with the third gear of the supercharger when in the second stage, the supercharger system of the 213E-series was essentially regarded completely unreliable. Junkers themselves and field mechanics couldn't even agree on the idle setting for this motor. It's serviceability was horrendous. From around 8-9.5km altitude the output and operation of the motor was unreliable, whilst following the shallow dip and climb to make 11.5km to engage the GM-1 system, once this oxidant kicked in the supercharger couldn't decide which gear to be in and all performance above this height was unreliable.

During service the Ta152H typically engaged at 7km altitude, although pilots remarked its performance at this height was extremely strong and whilst none apparently took it up to find out, all cited that they believed it would perform equally well to 12km and beyond (which was the reputation of the a/c rather than individual experience). Their reports however concentrate on the diving strength of the Ta152H in the boom and zoom manoeuvre from 7km to ca.3km and then back up to 8km in the zoom, claiming fantastic speeds in the dive (800km/h and thereabouts, which is unlikely but there is no doubt it was pretty damn good). They claim nothing else came close to its performance in this type of tactic.

The excerpts continue to cite the further developments of the Jumo motor became stillborn largely due to the vast difference between calculated and actual performance, the 213 was a tremendous disappointment whilst the DB603 was looking like the ducks guts Tank always said it would be, with its ca.10km critical altitude, better specific power output and similar weight (with anciliaries, ie. as a power egg).

The thing to keep in mind about the Jumo 213E-series is that even where it is functioning as calculated performance indicated, ie. with a bit of wishful thinking, performance dropped off markedly at 10.8-11.3km, then again at 12km and again at 13km, requiring shallow dip and climb manoeuvres to pass these height-barriers until the next gear could lock up under GM-1 injection.

My mental picture of the explanations provided are this, think of a car with an automatic transmission and a turbocharger, at 100km/h when the turbo kicks in for high gear acceleration, instead of propelling the car faster the auto transmission decides to kick back to a lower gear instead, and the lower gear has already run out of puff at 110km/h. So you get a lot of noise and rpm but actually go absolutely nowhere. This is what the Jumo supercharger gears did when you hit the GM-1 at high altitude, it suddenly reacted like you were at a lower altitude and needed a lower gear, but got confused as to which gear precisely is best between intake and ambient pressures, so it might use the intermediate gear at 11.5km and the low alt gear at 12.5km, one puts out like 650PS under heavy loading at full throttle and opens all the supercharger pressure release valves and the other revs its ring off for 800PS and blows the motor. That highly complicated supercharger didn't know what the hell it was doing and poor thing didn't have an ECU to tell it (it was all hydraulic shift mapping back then which is very pressure sensitive and prone to confusion in any unusual condiitions).

Even functioning as it should, taking the Ta152H any higher than 10.5km is a matter of just barely making the next altitude stage (ca.1km intervals) under GM-1 with a very high alpha by the skin of your teeth under stall conditions in thin air with a totally unreliable cockpit pressurisation system that barely manages to keep the exhaust fumes out of the cockpit, let alone makes for a comfortable ride.

Ta152H was best 7-9km. Ta152C even with its smaller wing was better at 10km. 603EC (1.95atm) motor was also superb at low alt (617km/h at sea level tested in 152V6), the two variations of this motor (603LA and 603EB/C) were earmarked by the end of hostiliites to take over where the Jumo213E-series had clearly proven a disappointment.
The real strength of the Ta152H with the Jumo213E was breaking 700km/h reliably by 7km on up but its performance at very high altitude exceeding 10.5km was questionable at best and required specialised piloting techniques to attempt. By the same token the 603 motor could break 700km/h a thousand metres lower and maintain a reliable service ceiling a thousand metres higher if performance altitudes without GM-1 are to be considered, whilst its supercharger type was much more reliable for use with GM-1 at extreme altitude (it didn't have gears to mess things up with when you tossed the switch).

Anyways this is what I've gathered from my readings, as I was quite interested in these motors for a bit. Is there any demonstrable reason I should reconsider?

 

[davebender]

How much WWII aerial combat took place above 10,000 meters? I suspect not very much. Performance from ground level (to catch CAS aircraft) up to about 9,000 meter (to catch heavy bombers) is what counts.

 

[drgondog]

All the performance figures for the Ta-152H are with a fuel load of 594 Liters of B4 fuel (Fighter configuration). With a full fuel load of 1109 Liters as used for long range reconnaissance or escort duties the weight was 5,220 kg.

Time to climb to 32,800 ft was 10.1 min for the Jumo 213E powered Ta-152H. The take off run was a mere 295 meters. With an extra 450 hp I suspect a time of 7.5 min to 10 km and a 245 m take off run.

According to this chart (http://www.wwiiaircraftperformance.org/mustang/p-51h-booklet-pg15.jpg) it took the P-51H ~9.5 min to reach 32,500 ft at 90" Hg. Question is then, when was the P-51H ready to be run at that power? 1947 ?

Not sure what you are referring to in the chart. It was 'ready' in February 1945 - certainly as ready as any Ta 152 relative to predictable versus actual production performance with the 213E at max boost.

at 90" and 8,000 GW it takes 10min to reach 40,000 feet, at 9000 GW (~ 400 pounds less than interceptor GW TO ) it takes 10 min to reach 37,000 feet.

For 9.5 min it looks like 38,000 and 35,000 feet respectively for 8000 GW and 9000 GW at 90"/3000rpm

Extrapolating for 32,500 feet it looks like ~6min for 8000 GW and 8min at 9000 GW for 90" boost.

These charts are for production fighters - all the data contained in the manual is used for flight planning for the respective roles.

What do you have that is comparable for the Ta152 that configures the fighter by weight, fuel, stores, climb to cruise, proceed to range limit with reserve of fuel and return to base with a reserve?

 

[davparlr]

Found a chart with the Ta-152H-1's performance with the EB engine, and it was calculated to be 626 km/h at SL and 762 km/h at 9.5 km. (The chart has been posted by me here before) There was no calculation for performance with GM-1 engaged, but the speed at 9.5km is 15 km/h faster than with the E series so I'm guessing it will be about the same with GM-1 engaged, suggesting a calculated high alt speed of ~775 km/h.

So the improvement introduced with the EB engine would atleast be +31 km/h at SL and +15 km/h at altitude.

I have no capability to affirm or deny your numbers, but they seem logical to me.

It should be noted however that the top speed of 760 km/h for the Jumo 213E powered Ta-152H-1 was calculated as-well, and like with all FW performance charts it was a very conservative figure. The Ta-152H-1's top speed with GM-1 engaged at high alt was never officially tested, and according to operational pilots it was considerably faster than the calculated figures, a top speed of over 500 mph having been observed.

However, the logic of operational pilot's observations regarding their steeds leaves a lot to be desired. Now, maybe the Ta has a TAS indicator and the estimates may be better, but I would have questions on how accurate is the indicator.

Davparlr,

Didn't they test the P-51H at 90" Hg and find it took more than 10 min to reach 30,000 ft ?

The only test I found where the time to reach 30k ft. was 10 minutes was a flight test of a/c 44-64161 dtd 1 May, 1945. However, in that test, aircraft boost was limited to 67" Hg due to water injection problems. It noted that 90" Hg could not be tested.

Another test, where the time was close to 10 minutes was a test of a/c 44-64182 dtd 14 Oct., 1946, where the time to 30k ft. was 9.5 minutes. However, this test appeared flawed. First, the hp output of the tested engine was significantly below specified performance over envelope. Second, data showed almost negligible performance improvement over the 67" boost engine in the 1 May, '45 test, e.g., time to climb to 33k ft was 11 minutes for the 90" boost, compared to the 11.2 minutes for the 67" boost. This is difficult to believe with 400 + more hp increase. Third, performance was significantly different from the calculated performance (NAA), which had been calibrated by wind tunnel and flight test.

I have access to five sources for the P-51H. Three at Spitfireperformance of data including an NAA report, flt test of 44-64161 tested at 67" hg, flt test of 44-64182 at 90" Hg, the F-51H Standard Aircraft Characteristics from drgondog, and one from a pamphlet from wwiiaircraftperfomance. This is how they panned out in time to climb to 33k (10 km) at a gross weight of about 9500 lbs:

NAA, 25 Sep, 1945 - approx 9.0 min (calculated at 90"Hg)
A/C 161 – 11.2 min (Max power at 67"Hg)
A/C 182 – 11 min (90"Hg)
F-51H – No direct comparison but climb rate is similar to Sep, 45 NAA document.
Pamplet – 7-7.5 min at 9000 lbs

The NAA document looks good in that it was a revision of a previous document and that it had been correlated to wind tunnel and flight test. It probably represents the best nominal performance of the P-51H and appears to have been accepted as such by the AF. A P-51H, with all parts and manufacture meeting specs, should obtain this performance.

Except where noted, the data for the P-51H is taken with full internal fuel, approximately 255 gallons, for a takeoff weight of about 9500 lbs . If the fuel load was the same as that tested in the Ta-152H (594 liters or 157 gallons), the takeoff weight of the P-51H would be about 8800 lbs, or 600 lbs lighter. With that correction made to the NAA numbers, I come up with about 7-7.5 minutes to 33k ft. (10 km), or about what the pamphlet shows.

All the performance figures for the Ta-152H are with a fuel load of 594 Liters of B4 fuel (Fighter configuration). With a full fuel load of 1109 Liters as used for long range reconnaissance or escort duties the weight was 5,220 kg.

Time to climb to 32,800 ft was 10.1 min for the Jumo 213E powered Ta-152H. The take off run was a mere 295 meters. With an extra 450 hp I suspect a time of 7.5 min to 10 km and a 245 m take off run.

At 9485 lbs, the no-wind takeoff roll of the P-51H is 1030 ft (314 m). Factoring in 8800 lbs for a takeoff weight, and throwing some chicken bones on the floor, I read that takeoff roll would be just about the same as the Ta-152H with the EB engine. With a better power to weight (.26 hp/lb to .23 hp/lb) and better wing loading (37.8 lbs/sqft to 42.6 lbs/sqft), this shouldn't come as a surprise.

According to this chart (http://www.wwiiaircraftperformance.o...oklet-pg15.jpg) it took the P-51H ~9.5 min to reach 32,500 ft at 90" Hg. Question is then, when was the P-51H ready to be run at that power? 1947 ?

The number you quote is, of course, using 80" Hg. There is no indication that 80" or 90" Hg was or was not available at the end of WWII. There was an attempt to verify 90" Hg spec performance 1 May, 1945, but water injection malfunctions prevented this test. The record for the stated follow-up is not available to me.

 

[drewwizard]

I did a bit of reading on the Hornet. Essentially a single pilot version of the Mosquito. More aerodynamic, smaller wings, same power plants. 4 - 20mm cannon in the nose. It was used in several wars/skirmishes in south east asia, so saw combat and was successful. Just short lived in the age of jets. If I remember right, it was available at the end of WWII, but like the all the late war aircraft, they were not sent into combat as the war was essentially won with the current inventory.
You can also throw in the super corsair into that mix.

 

[drewwizard]

The Ta-152 was slated for the 3,000HP jumo 222, which simply didn't materialize supposedly due to politics as much as teething issues. 1,930 HP at 29,000 feet. Probably the limit for piston engined aircraft, just too late in the war for even a prototype. I watched a rerun of the reno air races today. Modified griffon engines in p-51 mustangs were in this same HP class. Speeds of 534+ MPH claimed on the side of one racer.

The hornet was equipped with two derated merlin engines in the 2,000HP range. During at least one air race the hornet averaged 436 MPH, not particularly slow. The big advantage was clime (4,000 feet per minute) and range (1,480) miles. If you take Saburō Sakai's key requirements for a fighter, then the Hornet has both.

 

[pbehn]

The Ta-152 was slated for the 3,000HP jumo 222, which simply didn't materialize supposedly due to politics as much as teething issues. 1,930 HP at 29,000 feet. Probably the limit for piston engined aircraft, just too late in the war for even a prototype. I watched a rerun of the reno air races today. Modified griffon engines in p-51 mustangs were in this same HP class. Speeds of 534+ MPH claimed on the side of one racer.

The hornet was equipped with two derated merlin engines in the 2,000HP range. During at least one air race the hornet averaged 436 MPH, not particularly slow. The big advantage was clime (4,000 feet per minute) and range (1,480) miles. If you take Saburō Sakai's key requirements for a fighter, then the Hornet has both.

De rated to 2000HP? Wow imagine how fast it could have gone,

 

[Elmas]

Fiat G-56.

 

[tomo pauk]

The Ta-152 was slated for the 3,000HP jumo 222, which simply didn't materialize supposedly due to politics as much as teething issues. 1,930 HP at 29,000 feet. Probably the limit for piston engined aircraft, just too late in the war for even a prototype. I watched a rerun of the reno air races today. Modified griffon engines in p-51 mustangs were in this same HP class. Speeds of 534+ MPH claimed on the side of one racer.

The P-47M and N were powered by 2800 HP up to 32000 ft, I'm sure that it represents a level of altitude power that no-one bested in a production 1-engined fighter of ww2 vintage.

The hornet was equipped with two derated merlin engines in the 2,000HP range. During at least one air race the hornet averaged 436 MPH, not particularly slow. The big advantage was clime (4,000 feet per minute) and range (1,480) miles. If you take Saburō Sakai's key requirements for a fighter, then the Hornet has both.

Hornet was not equipped with two de-rated Merlins, but the latest from UK production, that just missed the ww2 use. 475 mph.

 

[drewwizard]

The merlins were derated in the hornet. Boost was significantly limited. You have to remember at this time, jets were going to be the future fighters. If piston engine fighters were the only choice, then the hornet would have had two griffon engines and 90 inches of Hg boost. The same with the Jumo-222. Jet engines were the future of bombers and fighters. Why drop a ton of cash into a new piston engine. Better to make it a research project (Jumo 222) just in case. Now for attack aircraft, fast and agile piston engined aircraft were still ideal. (turbo props were still a dream). If you assume no jets, then a whole different aircraft development timeline for piston engines becomes reality. R-4860 super corsairs become desirable and are pushed forward.

 

[pbehn]

The merlins were derated in the hornet. Boost was significantly limited. You have to remember at this time, jets were going to be the future fighters. If piston engine fighters were the only choice, then the hornet would have had two griffon engines and 90 inches of Hg boost. The same with the Jumo-222. Jet engines were the future of bombers and fighters. Why drop a ton of cash into a new piston engine. Better to make it a research project (Jumo 222) just in case. Now for attack aircraft, fast and agile piston engined aircraft were still ideal. (turbo props were still a dream). If you assume no jets, then a whole different aircraft development timeline for piston engines becomes reality. R-4860 super corsairs become desirable and are pushed forward.

The Hornet briefly filled a niche, immediately post war, jets had no range, using Griffons not only makes a bigger heavier aircraft it does nothing for its range or carrier capability. The De Havilland Hornet and Vampire jet entered squadron service at about the same time in 1946.

 

[tomo pauk]

The merlins were derated in the hornet. Boost was significantly limited.

Since you didn't posted any meaningful numbers to back up your claim, nor provided any source, this is just your opinion that I don't agree with. In other words - do you have a proof that Hornet was powered by derated Merlins?

[/QUOTE]You have to remember at this time, jets were going to be the future fighters. If piston engine fighters were the only choice, then the hornet would have had two griffon engines and 90 inches of Hg boost. The same with the Jumo-222. Jet engines were the future of bombers and fighters. Why drop a ton of cash into a new piston engine. Better to make it a research project (Jumo 222) just in case. Now for attack aircraft, fast and agile piston engined aircraft were still ideal. (turbo props were still a dream). If you assume no jets, then a whole different aircraft development timeline for piston engines becomes reality. R-4860 super corsairs become desirable and are pushed forward. [/QUOTE]

I have to remember what there was, not what other people order me.
Hornet with two Griffons would've been a beast size of F7F, much more expensive and unsuitable (once converted) for carrier-vessel work just like the F7F. Decision to go with Merlins 130 series was a good one, albeit too late for ww2.
The Jumo 222 was relegated to a merely research project not beacuse brass decided so, but because the reliability problems and lack of clear goals (power, relibility, timetable) made a trainwreck from the whole program.

 

[J.A.W.]

In 1945 both the RAF & USAAF were seriously jet-bent, & only begrudgingly accepted the Hornet/P-82,
- for roles the thirsty/inefficient turbojets - could not realistically undertake.

Navies were forced by turbine shortcomings to delay their uptake of early jets,
so the final-gen piston jobs lasted longer with them.

'One that got away' from the RAF - is featured by fellow member Bill Pearce on his blog, & she's a real beaut..

Hawker Fury I (Sabre-Powered) Fighter

 

[pbehn]

In 1945 both the RAF & USAAF were seriously jet-bent, & only begrudgingly accepted the Hornet/P-82,
- for roles the thirsty/inefficient turbojets - could not realistically undertake.

On the British side that was probably because the first jet to take to the air was substantially faster than the RAFs front line fighter, it did 350MPH on its first proper flight tests in 1941 and a fastest of 505MPH in 1943. Other nations made exactly the same judgement, the era of props was over, they would fill in niches and still do.

 

[J.A.W.]

Actually, if you read the RAF's appraisal of the early Meteor's combat capability,
'damned by faint praise' - just about sums it up (while carefully phrased in 'must please the boss' terms)..

& so the Brits then began the 'grandads axe' development routine of improvements,
extra-tankage, reinforced structure, clipped wings, tail graft, & new turbines, with much more thrust..

Meanwhile, the MiG 15 & F-86 showed up clearly what Britain really ought to have been doing..

 

[pbehn]

Actually, if you read the RAF's appraisal of the early Meteor's combat capability,
'damned by faint praise' - just about sums it up (while carefully phrased in 'must please the boss' terms)..

& so the Brits then began the 'grandads axe' development routine of improvements,
extra-tankage, reinforced structure, clipped wings, tail graft, & new turbines, with much more thrust..

Meanwhile, the MiG 15 & F-86 showed up clearly what Britain really ought to have been doing..

Quite possibly but the Mig 15 and F-86 were also jets as was the De Havilland Vampire.

 

[J.A.W.]

Sure, but the purpose designed swept-wing 2nd gen jets - were not flying in WW 2.

In one of his his 'Test Pilot' books, Roland Beamont describes besting a Vampire flown by Geoff de Havilland,
- in a mock combat - 'mix-up' - during wartime testing of the Tempest, for Hawker..

& in testing the Meteor also proved unable to intercept the Spitfire PR. 19 during its
routine high-fast recce-sorties..

 

[drewwizard]

The Hornet engines were derated to a maximum boost of 25LB/sq.in. It was a special version of the merlin with a slimmer profile to have reduced frontal area. (Range was more important than raw performance for this design) The hornet was an incredible aircraft, and one I followed for a while. I just saw where one is being rebuilt to flying standards. I didn't think any were left. Apparently they found enough to rebuild in New Zealand. It would be very nice to see one of these fly.