Author Topic: AH Spitfire Mk V vs AH 190 A5 Tests (Read 5460 times)

Wilbus · « **Reply #120 on:** October 06, 2002, 03:56:29 AM »

The 12 boost was for WEP, and was like Neil says later raised to 16 lbs. But 12 was initally WEP and then 16 was WEP. We have the later version.

Neil Stirling · « **Reply #121 on:** October 06, 2002, 04:41:02 AM »

Spitfire V speed using +16lbs boost,http://www.fourthfightergroup.com/eagles/spit12afduspeed.gif
Neil.

Neil Stirling · « **Reply #122 on:** October 06, 2002, 04:44:00 AM »

Spifire V climb using +16lbs boost. http://www.fourthfightergroup.com/eagles/spit12afduclimb.gif

Nashwan · « **Reply #123 on:** October 06, 2002, 06:52:01 AM »

Forget what the AH boost guage shows, the AH Spit V has the same speed (under WEP) as a Spit running 9lbs boost, and the same climb as a Spit V running 12lbs boost.

It is about 10 - 12mph too slow below 12,000ft to be running 16lbs boost, and the rate of climb is about 300 ft/min too low to be running 16lbs boost.

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Nash, the Spit V was able to use +12lbs boost from the date of its entry into service, this was intially used for take off.

All the test reports seem to be done at 9lbs max. Was 12lbs limited to take off only, not emergeny combat power, at least until some time in 1942?

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However, this 19lbs vs 23,5 lbs throws new light over this. All spit people seem to think the Spit was run at much less boost then the 190 which in that case is very wrong.

I don't think anyone has meant the Spit was run at least boost than the 190, simply that the 190 was run at its maximum, whilst the Spits were run below their maximum.

If a 190 is run at 4.5lbs boost, it's running it's maximum emergency power, ie WEP. If the Spit V were to be run at 4.5lbs boos, it would be at cruising power.

Wilbus · « **Reply #124 on:** October 06, 2002, 07:02:42 AM »

No Nash, 4,5 lbs (1.35 ata) was NOT wep, WEP was quite a bit above that, atleast 1,42 ata.

The spitfires were run at WEP (12lbs) for speed trails. This was the MAX boost they could put out at the time untill they were improved. So that the Spit was run on less boost then it could it wrong, it run at max boost it could. Upgraded versions arived later.

9 lbs boost was maximum contineus climbing power, all tests except 3 minute speed trails were 9 lbs vs the 4.5 lbs in the 190. The 190 speed trails were at 1.42 ata (whatever that is in lbs). Spit 5 speed trails were at 12 lbs. Spit 9 speed trails were at 16lbs and it still got outaccelerated by the 190. Meening the spit 5 would be too.

Wilbus · « **Reply #125 on:** October 06, 2002, 07:04:24 AM »

The 190 engine during the tests was troublesome aswell, it gave rough running and had be repaired using He111 engine parts. Against the spit 14 and tiffie the trails were abondoned due to the 190 engine being too bad.

Nashwan · « **Reply #126 on:** October 06, 2002, 07:24:32 AM »

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No Nash, 4,5 lbs (1.35 ata) was NOT wep, WEP was quite a bit above that, atleast 1,42 ata.

Not until the A5.

1.42 was the designed max, but it caused probems, and in service the aircraft were derated, with 1.35 becoming WEP, 1.28 max continuous.

Wilbus · « **Reply #127 on:** October 06, 2002, 07:48:15 AM »

Not in the test Nash, 1,42 was used as WEP for the 3 minute speed trails. The problems were fixed in the A4. A4 and A5 uses the same BMW 801D2 engine with possibility for MW50.

Guppy · « **Reply #128 on:** October 06, 2002, 10:46:09 AM »

I'm curious... the P-38F had 1,325 hp engines, didn't it? In the test report, it's stated that maximum power was 2,800 rpm, 42" manifold pressure. I don't have a P-38F manual, but the P-38J/L ratings for grade 91/96 fuel show 1,325 hp corresponding to 3,000 rpm and 47" MP.

I'd estimate 2,800 rpm / 42" MP as about 1,150 hp, which matches the P-38E's engines. Was someone using an old manual, or is there another reason?

Urchin · « **Reply #129 on:** October 06, 2002, 11:30:10 AM »

Whats the difference between 'ata', manifold pressure, and boost? All this stuff makes my brain hurt. I noticed that our 190 runs at like 39 manifold pressure. What is that in 'ata' and boost? How do you know what it is?

Neil Stirling · « **Reply #130 on:** October 06, 2002, 12:57:56 PM »

Nash,

" All the test reports seem to be done at 9lbs max. Was 12lbs limited to take off only, not emergeny combat power, at least until some time in 1942? "

all the tests I have seen are either at +9lbs or +16lbs boost, I do have a performance estimate for +12lbs.
Plus 12lbs boost was initially and officially used for take off only, however I don't think there was any way of preventing its use during combat.
The height at which the aircraft acheives its max speed indicates what boost pressure is being used, hence the big difference between +9lbs and +16lbs.

Neil.

illo · « **Reply #131 on:** October 08, 2002, 07:36:49 PM »

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Originally posted by Nashwan
The AH 190 runs at 1.3 ata, the AFDU tested theirs at 1.35 ata. That means the ADFU 190 will be faster. (assuming acceleration test were carried out at 1.35, and not WEP)

Is the A5 heavier than he A3? If so, the AFDU 190 will accelerate faster than the AH 190.

Probably depends on altitude.

AH 190A-5 should run at 1.42ata. (Start und Notleistung)
ADFU 190 was run at 1.42ata.

Performance should be almost identical.

However operatinal 190As until 190A-5 were usually restricted to 1.32ata to extend engine life. A-5 and later A-variants had 1.42ata maximum boost.

Bombjack · « **Reply #132 on:** October 09, 2002, 04:27:09 AM »

Wilbus, you should try your acceleration tests at something other than 10,000 feet. The Spit V was faster and better climbing than the 190 at that altitude; of course it would out-accelerate it.

Wilbus · « **Reply #133 on:** October 09, 2002, 04:56:45 AM »

Bombjack, read the RAF tests?

The A3 outaccelerated both the Spit 5 (slower then our Spit 5) and the Spit 9 (same as teh Spit 9 we have). The Spit 9 didn't out-accelerate it at any alt. Specially not in dives and in zoom climbs.

Bombjack · « **Reply #134 on:** October 09, 2002, 10:00:29 AM »

Wilbus,

Yes I am quite familiar with the AFDU tactical trials. However as a courtesy to you I went back and re-read them. I saw nothing to make me change my assertion.

You should realise that the tactical trials were intentionally broad in scope. They did not go into such detail as "at 10,000 feet the FW-190 has greatly reduced power since it is still well above critical altitude for the first blower stage, yet below that for the second; by comparison the Spitfire MkV is at critical altitude for its single stage blower, and (at this altitude only) enjoys a slight performance advantage." - but this would be exactly right, as evidenced by Neil Stirling's post on this page.

So, I repeat, conduct your level acceleration tests at a height other than 10,000 feet if you wish to replicate the AFDU comparisons.