Lockheed P-38 Lightning
Thanks mauld. Nice video, and the a/c looks great in the metal. So the P-38 has handed airscrews. That and the tricycle L/G would help on T/O, but the rudders look quite small for the asymmetric case. I wonder how it compares with the Mozzie.
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Love the growl when it's taxying, sounds very different - and great in the air too!
For those who love multi-engined Lockheeds, the P-38 will be sharing the Duxford flight line at Flying Legends with Breitling's Super Connie... As I recall, the Connie's wing is up-scaled P-38...
For those who love multi-engined Lockheeds, the P-38 will be sharing the Duxford flight line at Flying Legends with Breitling's Super Connie... As I recall, the Connie's wing is up-scaled P-38...
They drive on the right in the USofA so why not start the nearside motor first?
Merlins wouldn't have been much help in period as RR didn't offer reverse prop. rotation until the 130 series for the DH Hornet - but at least the Derby designers added an idler to the reduction gearbox rather than reversing rotation of the whole motor!
Merlins wouldn't have been much help in period as RR didn't offer reverse prop. rotation until the 130 series for the DH Hornet - but at least the Derby designers added an idler to the reduction gearbox rather than reversing rotation of the whole motor!
"Lots of breeze over the fin from the remaining engine .... "
Yes John, I didn't think of that till later. It seems a very logical config.
Maybe someone might give us a figure for Vmca, and a typical all-engine initial climb speed. Presumably, there wouldn't be a "critical engine"?
Re taxiing, it seems easily steerable, even at very low speeds, with little sign of ruddering or asymmetric power, and no tell-tale sounds from the brakes. I wonder if the nosewheel is steerable, rather than simply castoring?
Yes John, I didn't think of that till later. It seems a very logical config.
Maybe someone might give us a figure for Vmca, and a typical all-engine initial climb speed. Presumably, there wouldn't be a "critical engine"?
Re taxiing, it seems easily steerable, even at very low speeds, with little sign of ruddering or asymmetric power, and no tell-tale sounds from the brakes. I wonder if the nosewheel is steerable, rather than simply castoring?
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Wonder what would it have been like with Merlins?
When Allison, who had all ready lost the P-51 business, heard about this they lobbied to have the a/c removed from RR Derby.
It was a 'commercial' decision to keep the Allison motors.
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Chris Scott
Maybe someone might give us a figure for Vmca, and a typical all-engine initial climb speed. Presumably, there wouldn't be a "critical engine"?
Maybe someone might give us a figure for Vmca, and a typical all-engine initial climb speed. Presumably, there wouldn't be a "critical engine"?
But a nice aircraft.
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Nice footage of an interesting plane. Regarding Chris Scott's question "how does it compare with a Mozzie", in my opinion nothing really compares with a Mosquito which, beyond all its virtues and vices, was perhaps the most versatile military aircraft ever, not just in service but also in the way its production was farmed out to "off target" locations and used less valuable metal.
Of course, I might be ever so slightly biased in favour of the Mosquito (and Hornet) due to my Grandad's involvement as a consultant on marine plywood forming techniques!
Of course, I might be ever so slightly biased in favour of the Mosquito (and Hornet) due to my Grandad's involvement as a consultant on marine plywood forming techniques!
Quote from on-top:
"In a sense both engines are aero dynamically critical as the outboard down going prop blades are both at the furthest point from the centre of yaw, strange design as that configuration must give a higher Vmca."
Never flown a handed twin, and my aerodynamics fails to grasp the difference between the thrust of the upgoing and downgoing blades. But, perhaps significantly, the prototype (XP-38) had inwardly-rotating airscrews, according to Jane's and William Green - the latter writing in 1961 (my emphasis):
"...the torque of the Allison V-1710-11/15 (C9) engines, which developed 1090 h.p. at 13,200 ft. was compensated by inwardly-rotating handed Curtiss Electric airscrews, a special version of the Allison engine being produced with a left-hand rotating airscrew shaft. Ground runs began at the beginning of January 1939, and the XP-38 flew for the first time on the 27th of that month... [...]"
That a/c crashed at the end of a record-breaking flight from California to New York on February 11, according to Jane's. Green continues:
"The YP-38s (Model 122s) [of which 13 were built for evaluation] were rdesigned for production and included the installation of V-1710-27/29 (F2) engines rated at 1150 h.p. for take-off [up from 1040 h.p. on the XP-38] with spur reduction gearing instead of the epicyclic type. The airscrews became outwardly-rotating, and the thrust line was raised..."
Quote from ian16th:
"I read somewhere that the USAAF in the UK, loaned a P-38 to RR at Derby to trial the use of Merlins."
Well, I haven't found that story, but P-38s did fly with non-handed airscrews. Bill Green again (my emphasis):
"The model 322 for the R.A.F. [...,] production parallelling that of the A.A.F.'s P-38E to which it was generally similar, [was designated as] Lightning I, [...] first flying in December 1941. The first 143 aircraft of the British contract were Model 322-61s which, dubbed "castrated P-38s" by the factory, had the turbo-superchargers and the opposite-rotating airscrews removed, and two of the early V-1710-C15 (R) engines rated at 1040 h.p. at 15,000 ft., the "R" suffix indicating right-hand rotation of both airscrew shafts. For some unexplained reason, the British Air Purchasing Commission had requested these modifications despite predictions by Lockheed that the performance would be much inferior to the A.A.F. model. Two Model 322-61s were tested at Boscombe Down in April-June 1942, but performance was so disappointing that machines shipped to the United Kingdom were returned, and the remainder of the order was cancelled. A.A.F.pilots found that the Model 322-61 was nose-heavy and unable to maintain formation with standard P-38Es above 12,000 ft., and [they] were, therefore, sent to a modification centre at Dallas, Texas, and subsequentky served as trainers and and for various experimental purposes under the designation P-322. The last 524 on the British contract were to have been 322-60 Lightning IIs with standard turbo-supercharged Allisons, but these were absorbed into A.A.F. contracts, [...]"
Sound familiar?
PS: I now see that Wiki has an extensive entry on the P-38. Reference to the British order is at the end of the "High-speed compressibility problems" section, for no particular reason, citing desired engine compatibility with the P-40. Note 3, however, adds that the Brits did not want to use turbo-superchargers, and that they suspected that an anticipated shortage of their supply might delay the a/c deliveries...
The origin of the Red Bull a/c is given in the "Postwar operations" section.
"In a sense both engines are aero dynamically critical as the outboard down going prop blades are both at the furthest point from the centre of yaw, strange design as that configuration must give a higher Vmca."
Never flown a handed twin, and my aerodynamics fails to grasp the difference between the thrust of the upgoing and downgoing blades. But, perhaps significantly, the prototype (XP-38) had inwardly-rotating airscrews, according to Jane's and William Green - the latter writing in 1961 (my emphasis):
"...the torque of the Allison V-1710-11/15 (C9) engines, which developed 1090 h.p. at 13,200 ft. was compensated by inwardly-rotating handed Curtiss Electric airscrews, a special version of the Allison engine being produced with a left-hand rotating airscrew shaft. Ground runs began at the beginning of January 1939, and the XP-38 flew for the first time on the 27th of that month... [...]"
That a/c crashed at the end of a record-breaking flight from California to New York on February 11, according to Jane's. Green continues:
"The YP-38s (Model 122s) [of which 13 were built for evaluation] were rdesigned for production and included the installation of V-1710-27/29 (F2) engines rated at 1150 h.p. for take-off [up from 1040 h.p. on the XP-38] with spur reduction gearing instead of the epicyclic type. The airscrews became outwardly-rotating, and the thrust line was raised..."
Quote from ian16th:
"I read somewhere that the USAAF in the UK, loaned a P-38 to RR at Derby to trial the use of Merlins."
Well, I haven't found that story, but P-38s did fly with non-handed airscrews. Bill Green again (my emphasis):
"The model 322 for the R.A.F. [...,] production parallelling that of the A.A.F.'s P-38E to which it was generally similar, [was designated as] Lightning I, [...] first flying in December 1941. The first 143 aircraft of the British contract were Model 322-61s which, dubbed "castrated P-38s" by the factory, had the turbo-superchargers and the opposite-rotating airscrews removed, and two of the early V-1710-C15 (R) engines rated at 1040 h.p. at 15,000 ft., the "R" suffix indicating right-hand rotation of both airscrew shafts. For some unexplained reason, the British Air Purchasing Commission had requested these modifications despite predictions by Lockheed that the performance would be much inferior to the A.A.F. model. Two Model 322-61s were tested at Boscombe Down in April-June 1942, but performance was so disappointing that machines shipped to the United Kingdom were returned, and the remainder of the order was cancelled. A.A.F.pilots found that the Model 322-61 was nose-heavy and unable to maintain formation with standard P-38Es above 12,000 ft., and [they] were, therefore, sent to a modification centre at Dallas, Texas, and subsequentky served as trainers and and for various experimental purposes under the designation P-322. The last 524 on the British contract were to have been 322-60 Lightning IIs with standard turbo-supercharged Allisons, but these were absorbed into A.A.F. contracts, [...]"
Sound familiar?
PS: I now see that Wiki has an extensive entry on the P-38. Reference to the British order is at the end of the "High-speed compressibility problems" section, for no particular reason, citing desired engine compatibility with the P-40. Note 3, however, adds that the Brits did not want to use turbo-superchargers, and that they suspected that an anticipated shortage of their supply might delay the a/c deliveries...
The origin of the Red Bull a/c is given in the "Postwar operations" section.
Last edited by Chris Scott; 7th May 2014 at 19:14. Reason: PS added
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Merlin P-38
The 8th Air Force (I guess Doolittle who was boss and known to think outside the square) in 1944 flew an aircraft from Bovington to Rolls Royce at Hucknall for trial installation of a pair of single stage two speed Merlin XX. Rolls test flew the aircraft in its Allison guise a number of times, but before any conversion work could be undertaken orders came from Washington that the aircraft was to be returned immediately. Lockheed itself did an extensive investigation of powering the aircraft with two stage Merlins, but did not progress with the idea.
Some commentators say Allison called in political favours, as they had already lost the P-51 business - to the Merlin.
Chris, in short the downgoing blade sees a greater angle of attack because of the nose up attitude of the aircraft, and hence creates more lift. Having the downgoing blade inboard creates less of a turning moment for the pilot to counteract in the event of an engine failure, and the aircraft can be controlled to a lower speed.
Lockheed changed the prop rotation from the prototype as wing tunnel work showed that the change in power on/off pitch moment could be reduced, so making the pilots gun aiming ability some what easier.
The take off safety speed is given as 130 MPH, and notes that it is possible by allowing excessive yaw, to stall the vertical tails, rudder forces will reverse and require considerable force to overcome, and material reduction in power on the good engine will be necessary. Prompt use of rudder and reduction in live engine output at the time of failure will preclude excessive yaw developing.
The 8th Air Force (I guess Doolittle who was boss and known to think outside the square) in 1944 flew an aircraft from Bovington to Rolls Royce at Hucknall for trial installation of a pair of single stage two speed Merlin XX. Rolls test flew the aircraft in its Allison guise a number of times, but before any conversion work could be undertaken orders came from Washington that the aircraft was to be returned immediately. Lockheed itself did an extensive investigation of powering the aircraft with two stage Merlins, but did not progress with the idea.
Some commentators say Allison called in political favours, as they had already lost the P-51 business - to the Merlin.
my aerodynamics fails to grasp the difference between the thrust of the upgoing and downgoing blade
Lockheed changed the prop rotation from the prototype as wing tunnel work showed that the change in power on/off pitch moment could be reduced, so making the pilots gun aiming ability some what easier.
The take off safety speed is given as 130 MPH, and notes that it is possible by allowing excessive yaw, to stall the vertical tails, rudder forces will reverse and require considerable force to overcome, and material reduction in power on the good engine will be necessary. Prompt use of rudder and reduction in live engine output at the time of failure will preclude excessive yaw developing.
Thanks for the clear explanation, Brian. (My multi-prop career was fairly short-lived.) So, given the safety-speed/Vmca of 130 mph, and that caveat against allowing excessive yaw to develop, any idea what the typical unstick and approach speeds are?
Guess that ferry flight would have been from Bovingdon, Hertfordshire?
Guess that ferry flight would have been from Bovingdon, Hertfordshire?
Yes, CS, Bovingdon: Bovington was armoured corps, now a tank museum.
Pity the poor historian!
1. There are a lot of contradictions in the writings about the P38 and Lightning 1. CS quotes William Green writing in 1961 but the same author writing in 1957 told it differently. Now all of us are entitled to change our opinion when research shows we were wrong but what can we make of the following:
W Green 1957:the USA was not anxious to have the turbo-superchargers exported to Europe at that stage of the war.
W Green 1960: the British Air Purchasing Commission had requested these modifications. .
Graham White 1995: . . did not have the General Electric turbosuperchargers due to a lack of supply.
2. here's another and my money is on White as he backs it with a period drawing
Green 1957 & 1960: V-1710-27/29 (F2) . . . with spur reduction gearing instead of the [former] epicyclic type.
G. White: . . . an overhung pinion . . . driving an internal type reduction gear. Many observers incorrectly assume the early V-1710s had epicyclic reduction gears because of the apparant symmetry of the reduction gear.
Pity the poor historian!
1. There are a lot of contradictions in the writings about the P38 and Lightning 1. CS quotes William Green writing in 1961 but the same author writing in 1957 told it differently. Now all of us are entitled to change our opinion when research shows we were wrong but what can we make of the following:
W Green 1957:the USA was not anxious to have the turbo-superchargers exported to Europe at that stage of the war.
W Green 1960: the British Air Purchasing Commission had requested these modifications. .
Graham White 1995: . . did not have the General Electric turbosuperchargers due to a lack of supply.
2. here's another and my money is on White as he backs it with a period drawing
Green 1957 & 1960: V-1710-27/29 (F2) . . . with spur reduction gearing instead of the [former] epicyclic type.
G. White: . . . an overhung pinion . . . driving an internal type reduction gear. Many observers incorrectly assume the early V-1710s had epicyclic reduction gears because of the apparant symmetry of the reduction gear.
There were three P38s in the kunia in PNG spotted from the air by a Crowleys pilot somewhere in the vicinity of Merauke. Late 60s or early 70s. They looked for all the world as though they had been dropped in a distinctly predetermined way with minimal damage. Cannot say whether anyone ever went closer with a recovery plan.
My contact says that there was some follow up research done that unearthed the extraordinary account (only verbal) that three American pilots had mistakenly fired on Australian soldiers on a beach somewhere near to where the Japanese where holding out at a location on the north coast.
In short time word had got around to the extent that Australian troops, probably in the Port Moresby region, were wanting blood. If there is any truth in the story, the American commander of the squadron dispatched the three pilots in their aircraft with the clear understanding they were to go missing. Obviously this would have potentially defused the tension and given the Americans an easier out than having to face confrontation with hostile allied servicemen.
My contact says that there was some follow up research done that unearthed the extraordinary account (only verbal) that three American pilots had mistakenly fired on Australian soldiers on a beach somewhere near to where the Japanese where holding out at a location on the north coast.
In short time word had got around to the extent that Australian troops, probably in the Port Moresby region, were wanting blood. If there is any truth in the story, the American commander of the squadron dispatched the three pilots in their aircraft with the clear understanding they were to go missing. Obviously this would have potentially defused the tension and given the Americans an easier out than having to face confrontation with hostile allied servicemen.
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any idea what the typical unstick and approach speeds are?
The normal approach is made at about 100 – 105 MPH with 10 inches of manifold pressure. Cut throttles over the runway and flare, touch down is about 75 MPH. For short field approach at about 85 – 90 MPH using 15 inches of manifold pressure, flare over the runway and close throttles just as the airplane makes contact with the ground.
Can you please quote your source?
Interesting that engine No2 started before No1