Bf-109 vs Spitfire vs Fw-190 vs P-51

[drgondog]

Drgondog
Finnish oppinion was for Bf 109 G-2 and G-6.
Typical cruising flight at 2500m at 0.9-1.0 ata, 420-440km/h IAS, 470-490 km/h TAS, consumption 250l/h, max flight time c. 1½h. Max distance c. 750km without any reserves.

Juha

Thx Juha - it reinforces how amazing the 51/Merlin combination was, in comparison to the 109 which isn't bad at all... but best cruise for ferry purposes was around 16K feet at 2000 rpm and 27" hg ------> 45-50gph (175-190 l/h) depending on weight, but at that setting it was slower than 440km/hr - so there is a trade off in comparing the two cruising speed for max range - if I understood your figures correctly.

Based on the above info, matching the 109G approximate max flight time to maximum distance suggests the happy combination of highest cruise speed to maximum distance - which is unusual.

In most airframes the longest flight times are at a lower speed and fuel consumtion, while the greater distance is achieved with higer speeds but lower maximum endurance times

 

[Kurfürst]

This one gives a pretty good comparison of range and endurance under comparable conditions - though keep in mind, the actual cruising speeds may differ:

 

[Juha]

Drgondog
also with 109 the longest flight times are at a lower speed and fuel consumtion but You may not have noticed my earlier message:
"According to Finns the problem with cruising at speeds of 450km/h or slower was fouling of the plugs and carbon monoxcide sweepage into the cockpit. Or strict translation "flooding of carbon monoxcide into the cockpit.""

So Finns tended to think that cruising at most econ speeds wasn't worth of the problems which arose with those lower speeds. There should has been a device for plugs cleaning, but that was disabled at least in late FAF G-2s (from at least MT-237 onwards, the MT-237 was the earliest FAF's 109 whose papers I have gone through) and was missing from G-6s, or was missing at least from those FAF's G-6s whose papers I have studied.

Anyway DB 605A had a good fuel efficency.

Juha

 

[Kurfürst]

Messerschmitt Bf 109G handbook has specific instructions how to avoid plug fouling at low cruise speeds... Finns should have read the handbook first.

Looking at it again, the English translation of the Finn manual is from March 1943; in April 1943 there is a German manual of the same kind instructing to open up the throttle from time to time to 1800 - 2000 rpm, while pulling the spark plug burning off hande(?) for 5 seconds :

 

[Juha]

Kurfûrst
as I wrote at least from MT-237 onwards there was no more the switch and in G-6s didn't even had the device, and that was the situation when the Finns got the planes, so the modification was made by the Germans. So reading the manual didn't help anything.

Juha

 

[Juha]

Item 116 sparking plug cleaner switch isn't installed

 

[Kurfürst]

That is odd - I wonder why the Finnish export aircraft didnt have this.. any idea?

BTW, since it looks like something from a finnish archieve, do you happen to have the mt 215 trials perhaps? Ie. performance/tactical report.

 

[drgondog]

This one gives a pretty good comparison of range and endurance under comparable conditions - though keep in mind, the actual cruising speeds may differ:

I agree, and thanks again. Loads and altitudes big difference maker

The 51B/D could both stay up longer with the 108gal tanks.. from my father's logbook he had 7:55 for the Frantic VII - he was first up and last down and still had an estimated 30-40 gallons left in the wings. That was fast cruise from Steeple Morden over Baltic to R/V at 14000 feet (below optimal cruise height) at Stettin, slow cruise to Warsaw, short fight over Warsaw, then slow cruise to Piryatin, then divert to Poltava before landing, to meet with Bomber CO to plan next day mission..

This was the longest single mission he flew during WWII.. there are a fair amount in the 6-6:30 hr range for Posnan, Munich, Brux

 

[Juha]

Kurfürst
why the cleaning system was disconnected/not installed. I have no idea. But anyway that had made in Germany. Have You any positive proof that very late LW G-2s or later Gs had the system installed? It clearly had been installed in early G-2s or at least it is mentioned in the G-2 parts and items list because the page in my photo is part of a list of exceptions in MT-401 from the G-2 parts and items list.

Possible reasons why delete the system:
It didn't worked as hoped
it had some unwanted side effects
Germans thought that the mere opening the throttle time to time was after all enought.

On MT-215, I have only seen the same info that You have already on your site. But Kokko flew test also with a couple other MTs. I can dig out the MT numbers and of course the WNrs of the other G-2s used in the tests and the timeframe when Kokko flew the tests but that is all.

Juha

 

[davparlr]

Davparlr,

You're not reading the chart correctly. The Ta-152H-1 reaches 760 km/h at 12.5 km with the E engine (Note GM-1 kicks in at 11.5 km).

Thanks for pointing this out. The chart is a bit faded but I should have caught that just by cross referencing my other references. I could have spotted that the max speed of the Ta-152 was at 12.5 km. Quite a bit difference from the altitude I quoted the airspeed from. This would have thrown a red flag.

However this is at Steig u. Kampfleistung, explaining why some Ta-152 pilots reached 500 mph in the a/c at Start u. Notleistung or Sonder Notleistung as Erich has noted before.

Please explain these German terms in English (alas, I am one of those language challenged Americans-I can speak Southern, though) and how they relate to allied expressions. Translating helps not at all. I know that normal power is max continuous, military power is typically 30 minute operation and max (combat, WEP (normally associated with water injection)) is 5-10 minutes.

As for the F4U-4's top SL speed, it is 368 mph (320 knots [592 km/h]) which is slower than the Ta-152H-1 with the E engine (597 km/h).

The reference books I have agree that the top speed of the F4U-4 at SL is between 374 mph and 381 mph. Also, several flight test reports on the F4U-1 show SL airspeed of 365 mph and one, with a special finish, did 376 mph. Also, the SL speed of the F4U-5 is 403 mph. I think your number is at the bottom end of the F4U-4 SL airspeed variation.

As for speeds with the EB engine, 770 km/h was the minimum expected top speed WITHOUT GM-1, with GM-1 speeds well above 800 km/h were expected.

As was the P-72 projections.

 

[parsifal]

Juha

I recall (very vaguely) that the Finns took over the Me 109Gs very rapidly, because of either the high need for a high performance fighter in Finland, or because the finns were afraid that the germans were going to commandeer their order. Could this perhaps explain the incompleteness of the copies received? Maybe earlier deliveries of 109s were not so incomplete?

 

[kool kitty89]

As was the P-72 projections.

Not to get into tht again, but the XP-47J exceeded 800km/h in testing, at 507 mph at 32,000 ft, and was relatively close to being ready for production (similar to the P-47M/N tumeline) so I don't know why you keep going back to the P-72 which was less practical in an immediate time span, and showed superior performance in testing. (with 4-bladed prop) IMO continued work on the P-47J would have been much more useful than concentrating on the P-72, as happened in reality.

 

[Juha]

Hello Parsifal
MT-237-248 were replacement a/c delivered to the FAF by the LW MU at Pori in Finland, it mainly served LW in Lapland (Northernmost part of Finland) and these a/c also had rather many exceptions. And they also did not have the plug cleaning system switch. IMHO it was deleted from all 109s at least from late 1943 onwards, maybe to simplify the production

MT-401, the first G-6 of the FAF, was delivered in spring 44, there was no special urgency at that time. IIRC what was new with the G-6s was that there were part of high pressure oil system flexible piping and hydraulic piping were not according to specs and Finns had to first replace them with pipes which match the specs before delivering the MTs to the sqn. At least that was in case of most G-6s which I had studied. But again IMHO this was because of urgent need to maximize fighter production in Germany. During summer 44 Finns got most of their 109Gs and then the situation was urgent but the last MT whose papers I have gone through is MT-421, which was delivered at the end of April 44 and the crisis began on June 10 44.

Juha

 

[davparlr]

Not to get into tht again, but the XP-47J exceeded 800km/h in testing, at 507 mph at 32,000 ft, and was relatively close to being ready for production (similar to the P-47M/N tumeline) so I don't know why you keep going back to the P-72 which was less practical in an immediate time span, and showed superior performance in testing. (with 4-bladed prop) IMO continued work on the P-47J would have been much more useful than concentrating on the P-72, as happened in reality.

I think it is interesting that they cancelled the P-47J in favor of the P-72. It seems the lowest risk approach. Incredible engine, 2800 hp at 32,500 ft.

 

[drgondog]

I think it is interesting that they cancelled the P-47J in favor of the P-72. It seems the lowest risk approach. Incredible engine, 2800 hp at 32,500 ft.

Makes you wonder about unit costs and how it compared against the 51H which was a new airframe as far as tooling goes?

 

[pbfoot]

. I had the chance to talk to a guy( 1 hour drive him and me he was doing the talking ) who is a check pilot in real life warbirds and he said the original WW2 notes are crap they would not even be considered as a tool in the real world today as they don't even indicate such things as humidity.

 

[kool kitty89]

Are you talking about the range figures?

Or a broader statement about the performance charts and data we've been using?

Or am I misunderstandibg your statement?

 

[pbfoot]

I'm talking about all the charts from that era , I wasn't aware how much humidity affected things . I was aware of how humidity affected flight itself but the light never came on in my mind on how it affected engine performance. If its humid the the engine performance degrades the reason being is the amount of moisture in the air affects the fuel air mixture . Water doesn't burn.
Max all up weight as reccomended by the book was almost always exceeded . One example given to me was the B25 which was supposed to have a max weight of roughly 27000lbs but was operated steadily at 32000lbs plus . The nose gear was only rated for 29000 lbs

 

[davparlr]

The P-51D never climbed that fast Davparlr. The lighter P-51B achieved 4,380 ft/min with 104/150 octane fuel at 75" HG.

The P-51B was only 300 lbs lighter than the D. At 67", the P-51B had a climb rate of 3750 ft/min. The P-51D climb rate at 67", was 3600 ft/min. This info is from flight test data. It is not unreasonable to believe that since the P-51B could climb at 4380 ft/min 75", the P-51D could climb at about 4200 ft/min at 75". I know that the -7 engine was cleared for 75" and that some P-51D pilot reports show it was used in combat.

Also, a check with a chart showing climb rate change with weight for the P-51D at SL shows about 200 ft/min rate change for 400 lbs weight change, which confirms the 4200 ft/min number.

 

[FLYBOYJ]

I'm talking about all the charts from that era , I wasn't aware how much humidity affected things . I was aware of how humidity affected flight itself but the light never came on in my mind on how it affected engine performance. If its humid the the engine performance degrades the reason being is the amount of moisture in the air affects the fuel air mixture . Water doesn't burn.

I think you're only getting half the story.

You are correct about humidity and how it affects fuel burn, but that's why you have mixture controls to continually lean the engine for compensation of humidity (and temperature and altitude). If leaned correctly you'll get the same performance at 10% relative humidity as you would at 98%. What humidity (and) heat really affects is aircraft (aerodynamic) performance. This is computed in "Density Altitude" performance and those charts are usually included in the pilot's POH.