RAF Preference for in line engines vs radials in WW2
Thread Starter
RAF Preference for in line engines vs radials in WW2
Most RAF aircraft seem to have used in line engines in WW2, the Spitfire, Hurricane, Lancaster are a few examples of this
The USAF still used radials in many of their types however, the P47, B17 and B29 etc, curious as to why this was
The USAF still used radials in many of their types however, the P47, B17 and B29 etc, curious as to why this was
Been written about over the years.
How did we get to here from there ? Here being WW2, and there being the first petrol engine manufactured that would predate winged aviation.
How did we get to here from there ? Here being WW2, and there being the first petrol engine manufactured that would predate winged aviation.
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Probably because in-line had a smaller frontal area, so less drag and were developed from the racing engines used in the likes of Schneider cup racers such as the S6.
In-line engines were water cooled - they had less frontal area, but had complex cooling systems and could be taken out by a single hit on the cooling system. Some of that drag advantage was given back due to the need for big radiators, plus you couldn't run them very long on the ground prior to takeoff without overheating.
Radial engines had more frontal area, but were air cooled so no plumbing, radiator, etc. and were far more tolerant of battle damage. Radial engined aircraft were preferred for ground attack due to the better tolerance to damage from ground fire, and since cooling airflow was provided by the turning prop, they didn't generally overheat sitting on the ground waiting to takeoff.
Radial engines had more frontal area, but were air cooled so no plumbing, radiator, etc. and were far more tolerant of battle damage. Radial engined aircraft were preferred for ground attack due to the better tolerance to damage from ground fire, and since cooling airflow was provided by the turning prop, they didn't generally overheat sitting on the ground waiting to takeoff.
Most versions of the Wellington
Most versions of the Beaufighter (the merlin powered version was a dog)
The most successful version of the Halifax
Stirling
Sunderland
Anson
Lysander
Beaufort
Most versions of the Master
Martinet
Botha
Gladiator
Albemarle
Swordfish
Albacore
One version of the Tempest
Harrow
Bombay
Most of the USAAF Fighters did use in-line engines
P-38
P-39
P-40
P-51
P-63
The US use of Radials Would have been because that was what powered most of their civil airliners in the pre war period. The British civil market was a cottage industry in comparison.
Thread Starter
A Lot of RAF/FAA British Aircraft in WWII didn't use In-line Engines,
Most versions of the Wellington
Most versions of the Beaufighter (the merlin powered version was a dog)
The most successful version of the Halifax
Stirling
Sunderland
Anson
Lysander
Beaufort
Most versions of the Master
Martinet
Botha
Gladiator
Albemarle
Swordfish
Albacore
One version of the Tempest
Harrow
Bombay
Most of the USAAF Fighters did use in-line engines
P-38
P-39
P-40
P-51
P-63
The US use of Radials Would have been because that was what powered most of their civil airliners in the pre war period. The British civil market was a cottage industry in comparison.
Most versions of the Wellington
Most versions of the Beaufighter (the merlin powered version was a dog)
The most successful version of the Halifax
Stirling
Sunderland
Anson
Lysander
Beaufort
Most versions of the Master
Martinet
Botha
Gladiator
Albemarle
Swordfish
Albacore
One version of the Tempest
Harrow
Bombay
Most of the USAAF Fighters did use in-line engines
P-38
P-39
P-40
P-51
P-63
The US use of Radials Would have been because that was what powered most of their civil airliners in the pre war period. The British civil market was a cottage industry in comparison.
Thats a very interesting comparison and the historical perspective you provided was just what I was looking for
A Lot of RAF/FAA British Aircraft in WWII didn't use In-line Engines,
Most versions of the Wellington
Most versions of the Beaufighter (the merlin powered version was a dog)
The most successful version of the Halifax
Stirling
Sunderland
Anson
Lysander
Beaufort
Most versions of the Master
Martinet
Botha
Gladiator
Albemarle
Swordfish
Albacore
One version of the Tempest
Harrow
Bombay
Most of the USAAF Fighters did use in-line engines
P-38
P-39
P-40
P-51
P-63
The US use of Radials Would have been because that was what powered most of their civil airliners in the pre war period. The British civil market was a cottage industry in comparison.
Most versions of the Wellington
Most versions of the Beaufighter (the merlin powered version was a dog)
The most successful version of the Halifax
Stirling
Sunderland
Anson
Lysander
Beaufort
Most versions of the Master
Martinet
Botha
Gladiator
Albemarle
Swordfish
Albacore
One version of the Tempest
Harrow
Bombay
Most of the USAAF Fighters did use in-line engines
P-38
P-39
P-40
P-51
P-63
The US use of Radials Would have been because that was what powered most of their civil airliners in the pre war period. The British civil market was a cottage industry in comparison.
The Secret Horsepower Race by Calum Douglas answers all the possible questions about the engine configuration choice of the British, American, and German manufacturer and is well worth a read. BMW for instance were basically told by the RLM to start building radials despite having no experience and started off by licence building some P&W models.
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In-line engines were water cooled - they had less frontal area, but had complex cooling systems and could be taken out by a single hit on the cooling system. Some of that drag advantage was given back due to the need for big radiators, plus you couldn't run them very long on the ground prior to takeoff without overheating.
Radial engines had more frontal area, but were air cooled so no plumbing, radiator, etc. and were far more tolerant of battle damage. Radial engined aircraft were preferred for ground attack due to the better tolerance to damage from ground fire, and since cooling airflow was provided by the turning prop, they didn't generally overheat sitting on the ground waiting to takeoff.
Radial engines had more frontal area, but were air cooled so no plumbing, radiator, etc. and were far more tolerant of battle damage. Radial engined aircraft were preferred for ground attack due to the better tolerance to damage from ground fire, and since cooling airflow was provided by the turning prop, they didn't generally overheat sitting on the ground waiting to takeoff.
The P51 with clever ducting actually produced thrust from the big radiator bulge on the undersde, not a lot, but more than enough to offset it's drag.
A site well worth a visit and read through.
https://enginehistory.org/
Nobody has mentioned availability yet. When designing a new aircraft type, you go to your (preferred) engine supplier(s) and see what they've got on the shelf/drawing board and how this fits your needs. Wright and P&W had a lot of radial types available or could produce them in sufficient numbers. RR had the Merlin available and could produce these in sufficient numbers. Other types may not have fitted the design as well as these did.
(I know that I am over-simplifying this... but it helps to get the point across. Nobody ever sat down and decided to only have radial engined fighters in the US and inline engined fighters in the UK, so the original question is also very much simplified, as already shown above.)
(I know that I am over-simplifying this... but it helps to get the point across. Nobody ever sat down and decided to only have radial engined fighters in the US and inline engined fighters in the UK, so the original question is also very much simplified, as already shown above.)
Last edited by Jhieminga; 24th Nov 2022 at 08:25. Reason: silly typos
Nobody has mentioned availability yet. When designing a new aircraft type, you go to your (preferred) engine supplier(s) and see what they've got on the shelf/drawing board and how this fits your needs. Wright and P&W had a lot of radial types available or could produce them in sufficient numbers. RR had the Merlin available and could produce these in sufficient numbers. Other types may not have fitted the design as well as these did.
(I know that I am over-symplifying this... but it helps to get the point across. Nobody ever sat down and decided to only have radial engined fighters in the US and inline engined fighters in the UK, so the original question is also very much symplified, as already shown above.)
(I know that I am over-symplifying this... but it helps to get the point across. Nobody ever sat down and decided to only have radial engined fighters in the US and inline engined fighters in the UK, so the original question is also very much symplified, as already shown above.)
I know there are lots of arguments for and against.
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A quick search brought up the Hurricane Mk VII Radial Hurricane with a Bristol Hercules installed
It says it flew with 320 squadron, but I can't find any other information. Another link on a modelers' site said it was a trial only
Not that the hurricane was an attractive aircraft, but in this configuration it's an aircraft only a mother could love
It says it flew with 320 squadron, but I can't find any other information. Another link on a modelers' site said it was a trial only
Not that the hurricane was an attractive aircraft, but in this configuration it's an aircraft only a mother could love
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A quick search brought up the Hurricane Mk VII Radial Hurricane with a Bristol Hercules installed
It says it flew with 320 squadron, but I can't find any other information. Another link on a modelers' site said it was a trial only
Not that the hurricane was an attractive aircraft, but in this configuration it's an aircraft only a mother could love
It says it flew with 320 squadron, but I can't find any other information. Another link on a modelers' site said it was a trial only
Not that the hurricane was an attractive aircraft, but in this configuration it's an aircraft only a mother could love
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A radial would indeed turn it into a complete abomination.
A quick search brought up the Hurricane Mk VII Radial Hurricane with a Bristol Hercules installed
It says it flew with 320 squadron, but I can't find any other information. Another link on a modelers' site said it was a trial only
Not that the hurricane was an attractive aircraft, but in this configuration it's an aircraft only a mother could love
It says it flew with 320 squadron, but I can't find any other information. Another link on a modelers' site said it was a trial only
Not that the hurricane was an attractive aircraft, but in this configuration it's an aircraft only a mother could love
Minimizing the frontal area (and resultant drag) of a big radial engine was non-trivial, but there were several highly successful designs that did that and gave the resultant fighter aircraft impressive top speed.
To name just a few:
F6F Hellcat
F4U Corsair
P-47 Thunderbolt
Japanese A6M Zero