Best piston engine(s) for fighters of 1945?

J.A.W. · Jan 23, 2024

Shortround6 said:
I am looking, I have also looked at the Griffon 69 mentioned on the page 4 of attachment. 2375hp.

What it rather interesting is that 2130hp is claimed at 15,500ft while the Sabre engine is about 2450hp at the same altitude on the graph in the article.
At 21,000ft the difference in power is a lot closer. The Griffon engine is over 450lbs lighter and the article claims a specific weight of 0.88lb/hp (low gear, max boost)
The specific weights I gave earlier were for max cruise.

edit. a lot of these engines have specs that bounce all over the place depending on when the specs were quoted. The Article explains rather well the differences between the late model Sabres and the earlier ones, there was a lot more than just screwing around with the boost settings
Even the article on the Griffon engine is about the changes in the power listed from an earlier article.

Yeah, the added R/R piece is interesting, it does show the Sabre still had it beat for power to weight - even with the Griffon at +25lb boost.
(That +25lb was on 150 grade 'hi-test' avgas - unlike the 'regular' 100/130 used by the Sabre), & 'normal/climb' settings for the Griffon?

Another point of interest is the English-Electric engine test cell, with electric dyno-power fed back into the local grid, & this set up may've
been seen by the Chrysler Corp Engineers when Sabre production 'stateside' was considered, since the Mopar guys later did it too, when
wringing out their big Wright radials, on their part of the priority #1 B-29 program...

J.A.W. · Jan 24, 2024

tomo pauk said:
Excellent choice, the -18W.
At 26000 ft, it was making 500 HP more than the vaunted Sabre VII.

If I am reading both charts correctly, then I must ask, is that "500hp" figure a typo, tomo?
Because they appear to be within 50hp of each other at that height, if you check...

wuzak · Jan 24, 2024

J.A.W. said:
Another point of interest is the English-Electric engine test cell, with electric dyno-power fed back into the local grid, & this set up may've
been seen by the Chrysler Corp Engineers when Sabre production 'stateside' was considered, since the Mopar guys later did it too, when
wringing out their big Wright radials, on their part of the priority #1 B-29 program...

Pratt & Whitney did that at their factories too, IIRC.

J.A.W. · Jan 24, 2024

tomo pauk said:
Excellent choice, the -18W.
At 26000 ft, it was making 500 HP more than the vaunted Sabre VII.

However, at WEP/Combat settings the mighty R-2800-C comes up a wee bit short at 2,600ft, but hey - only by ~700hp...

Power/altitude requirements dictated engine supercharger specs, wasn't the later Au-Corsair fitted with a low-level mill?

Does the Corsair pilot have 'single lever coordinated control' by 1945, 'cause the tempest pilot sure does...

tomo pauk · Jan 24, 2024

J.A.W. said:
If I am reading both charts correctly, then I must ask, is that "500hp" figure a typo, tomo?
Because they appear to be within 50hp of each other at that height, if you check...

See the chart here, for the power values with water injection (60 in Hg).

tomo pauk · Jan 24, 2024

J.A.W. said:
However, at WEP/Combat settings the mighty R-2800-C comes up a wee bit short at 2,600ft, but hey - only by ~700hp...

Power/altitude requirements dictated engine supercharger specs, wasn't the later Au-Corsair fitted with a low-level mill?

Does the Corsair pilot have 'single lever coordinated control' by 1945, 'cause the tempest pilot sure does...

Tempest's pilot does not have the Sabre VIII in 1945, while Corsair's pilot does have the -18W.
AU-1 was indeed fitted with the 1-stage S/Ced R-2800, being an attack aircraft; as a consequence, the oil system was now behind the engine, with armor under the engine and the oil cooler - all for extra survivability against the ground fire. Unfortunately, there was no such thing in reverse for the Sabre - ie. there was no hi-alt version to choose from.
The best of the fighter Corsairs (the -5) was outfitted with the even more capable engine than it was the -18W, but, same as with the Sabre VII, that was well post-1945

Metrallaroja · Jan 24, 2024

Yes, the AU-1 (F4U-6)uses the same engine as F8F-1 and F7F-3. Quite a good engine at low alttitude but lacks mid-high alt performance at high power settings.
The french requested an AU-1 version with high alt performance and the R-2800-18W was back on the F4U-7.
So high alt performance is important

F4U-5 engine is quite the performer, but as said it is beyond 45.

Geoffrey Sinclair · Jan 24, 2024

To end November 1945, Napier Sabre production
58 I
4,757 II
25 III
6 IV
89 V
27 VA
5 VI

Probably another 8 II, 6 V and 16 VA in December

Meantime 2,117 Griffon II to XII and 4,014 Griffon 61 to 89 by end November 1945.

J.A.W. · Jan 24, 2024

tomo pauk said:
Tempest's pilot does not have the Sabre VIII in 1945, while Corsair's pilot does have the -18W.
AU-1 was indeed fitted with the 1-stage S/Ced R-2800, being an attack aircraft; as a consequence, the oil system was now behind the engine, with armor under the engine and the oil cooler - all for extra survivability against the ground fire. Unfortunately, there was no such thing in reverse for the Sabre - ie. there was no hi-alt version to choose from.
The best of the fighter Corsairs (the -5) was outfitted with the even more capable engine than it was the -18W, but, same as with the Sabre VII, that was well post-1945

The Sabre VA was available, & that was essentially a non-ADI late-mark Sabre, with up to +15lb boost, which still bettered the equivalent
R-2800-C over most of the power/time settings range, esp' once the radial had exhausted its ADI & its CHT gauge was in the red.

The Tempest Mk VI was preferred over the Sabre-Fury, partly because the proven armour package from the Typhoon could readily be
fitted to the similar compact chin/beard radiator, as/when/if required.

As previously made plain, the RAF had no further interest in high-altitude piston-engine fighters, & the USN rapidly came to the same view.

Metrallaroja · Jan 24, 2024

J.A.W. said:
As previously made plain, the RAF had no further interest in high-altitude piston-engine fighters, & the USN rapidly came to the same view.

Lmao what are you talking about.
The hornet and the sea fury both have good performance at mid to high alt.
USN developed the F4U-5 and the F8F-2 which are high alt beasts.

J.A.W. · Jan 24, 2024

Metrallaroja said:
Lmao what are you talking about.
The hornet and the sea fury both have good performance at mid to high alt.
USN developed the F4U-5 and the F8F-2 which are high alt beasts.

The F8F was quickly phased out once a decent jet was aboard, (& they didn't get multi-stage supercharging) & the F4U was relegated to the
'mud-moving' role, like-wise.

The Hornet didn't get the high-altitude supercharger-equipped Merlin, by being multi-stage it was capable upstairs, but found no work there.

Edit: I'll link this, for those who missed it, earlier, Official RAF view: http://www.wwiiaircraftperformance.org/Fury/Sea_Fury_Flight.pdf

tomo pauk · Jan 24, 2024

J.A.W. said:
The Sabre VA was available, & that was essentially a non-ADI late-mark Sabre, with up to +15lb boost, which still bettered the equivalent
R-2800-C over most of the power/time settings range, esp' once the radial had exhausted its ADI & its CHT gauge was in the red.

Once the radial exhausted it's ADI, it's aircraft has already done it's job. Sabre V was still lacking high-altitude capabilities of the R-2800-18W.
Funny how the ADI is ripe with shortcomings when someone else does it, yet it is rainbows and unicorns on the Sabre VII.

J.A.W. said:
As previously made plain, the RAF had no further interest in high-altitude piston-engine fighters, & the USN rapidly came to the same view.

J.A.W. said:
The Hornet didn't get the high-altitude supercharger-equipped Merlin, by being multi-stage it was capable upstairs, but found no work there.

Spreading misinformation will not get you any friends here.

J.A.W. · Jan 24, 2024

tomo pauk said:
Once the radial exhausted it's ADI, it's aircraft has already done it's job. Sabre V was still lacking high-altitude capabilities of the R-2800-18W.
Funny how the ADI is ripe with shortcomings when someone else does it, yet it is rainbows and unicorns on the Sabre VII.

Spreading misinformation will not get you any friends here.

What "misinformation", check the supercharger ratios of the Merlin 130/131, & who knows how long a WEP setting might be needed?

Did you read the linked article, the RAF top brass position is clearly made.
Did you read the Sabre VII article, it auto-adjusted the ADI, in accordance with other relevant engine management parameters - fuel/ignition.

(One further attribute of the sleeve-valve, compare the max-permissible CHT for Centaurus/R-2800, the Bristol is more heat-tolerant,
and features auto-opening cooling gills).

Edit: See this chart linked, the Mustang has the high-altitude Merlin, & the Hornet does not, as the supercharger staging heights show:

http://www.wwiiaircraftperformance.org/Hornet/Hornet_I_Level_AFDS.jpg

don4331 · Jan 24, 2024

wuzak said:
Pratt & Whitney did that at their factories too, IIRC.

Ford definitely had the P&W engines they were building connected to generators feeding power back into the grid.

J.A.W. · Jan 24, 2024

Geoffrey Sinclair said:
To end November 1945, Napier Sabre production
58 I
4,757 II
25 III
6 IV
89 V
27 VA
5 VI

Probably another 8 II, 6 V and 16 VA in December

Meantime 2,117 Griffon II to XII and 4,014 Griffon 61 to 89 by end November 1945.

Can you kindly reference your source, Geoffrey? Were the Sabre IIC & IID figures included in your generic 'Sabre II' numbers?
It seems most of the intact (not crash relic) Sabre engines still extant are VIIs, (even though most of them, have been 'butchered').

tomo pauk · Jan 24, 2024

J.A.W. said:
What "misinformation", check the supercharger ratios of the Merlin 130/131, & who knows how long a WEP setting might be needed?

J.A.W. said:
Edit: See this chart linked, the Mustang has the high-altitude Merlin, & the Hornet does not, as the supercharger staging heights show:

You are free to believe what you want.
I'm not discussing the aero engines with you anymore.

wuzak · Jan 24, 2024

J.A.W. said:
Edit: See this chart linked, the Mustang has the high-altitude Merlin, & the Hornet does not, as the supercharger staging heights show:

http://www.wwiiaircraftperformance.org/Hornet/Hornet_I_Level_AFDS.jpg

The Mustang in that chart has the -7, which has the same gearing as the -130/-131. or nearly the same.

The increased critical altitude is due to the Mustang using less boost.

But you are right, the -130/-131 were not the high altitude version.

Jugman · Jan 24, 2024

don4331 said:
Ford definitely had the P&W engines they were building connected to generators feeding power back into the grid.

Pretty much everybody did that. I think a couple manufacturers pre-war were actually doing it on a limited basis. If you're using an electric dynamometer, what in blazes do you think you're doing with all that electrical power? You're not just going to run it through a resistor you're going to use the bloody stuff for something useful.

J.A.W. · Jan 24, 2024

Jugman said:
Pretty much everybody did that. I think a couple manufacturers pre-war were actually doing it on a limited basis. If you're using an electric dynamometer, what in blazes do you think you're doing with all that electrical power? You're not just going to run it through a resistor you're going to use the bloody stuff for something useful.

Hot water from the water-brake dyno - to provide a lovely sauna spa complex - for the hard-working 'engine-bashers'?

J.A.W. · Jan 24, 2024

wuzak said:
The Mustang in that chart has the -7, which has the same gearing as the -130/-131. or nearly the same.

The increased critical altitude is due to the Mustang using less boost.

But you are right, the -130/-131 were not the high altitude version.

Weren't RAF Mustang IIIs V-1650-3 equipped? & the V-1650-7 was only in late production P-51B/C for the USAAF, (& D/K/Mustang IV)?
(I'd assumed the "V-1650-1" notation on the chart was an error/typo).

Best piston engine(s) for fighters of 1945?

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