Page 1
Article Type: History
Article Date: May 10, 2001
The concept was always good from an engineering standpoint. Mount two engines on an airframe for better performance. This was true in the thirties when aircraft engines were more modest in output. But aside from longer range, due to the increased fuel storage capabilities, twins never outclassed singles. Some were total failures.
Sure, nose mounted guns gave a superior centerline firing axis but many single-engine fighters mounted guns on the fuselage for the same effect. Of course examples such as the excellent Mosquito and P-38 come to mind. But what else? Let's look at WWII's twin-engine fighters in detail for some comparisons.
When H.L. Hibbard's design team began design concepts for the Army Air Corp's required high-altitude, high-speed interceptor they adopted the configuration we all recognize today in the P-38. No single engine concept in the late thirties had the power to meet the specifications so the twin-boom layout evolved.
The P-38-J-25-LO was the best example produced in quantity beginning in 1943 with the 1-LO. Two turbo-supercharged Allison V-1710-89/91 V-12 liquid cooled engines of 1,425 hp each gave the plane a top speed of 414 mph at 25,000 feet. The 17,500 lb plane could climb to 20,000 feet in seven minutes with a ceiling of 44,000 feet. The range with maximum external fuel was long at 2,260 miles, though this would later be duplicated by the P-51. In fact the speed performance figures could be matched or excelled by many single-engine Luftwaffe fighters.
Armament was strong with four Browning .50s with 500 rpg and a Hispano 20mm with 150 rounds. Ten rockets could be carried and up to 1,600 lbs. of bombs could be mounted.
ETO P-38s were dismal in their combat record. There was a significant amount of technical malfunction due to the damp, cold European climate. The high-altitude edge it had in the Pacific was less significant in the ETO since many German fighters had good altitude performance. When in the MTO most of the combat ended up involving low altitudes where its ability to dive was much impaired. Luftwaffe fighters were more heavily armed than their Japanese counterparts too.
In the PTO it was a totally different story where it downed more aircraft than any American plane. Perpetual good weather allowed the P-38s to roam far and wide using altitude advantage, dive speed, level speed and zoom tactics to a superior level. But would Dick Bong, Tommy McQuire and the rest have faired as well in Europe? Probably not.
The DeHavilland Mosquito two-seat fighter was derived originally from a high-performance light bomber. With the RAF handling the Reich's night bombing the "Mossie" fighter or bomber version never really competed equally with their single-engine brothers. The daylight missions that the Mosquito flew were generally against ground targets and at night it was a completely alien environment though night-fighting variants excelled.
Owning partly to its wonderful wooden airframe of lightweight and high strength, the Mosquito had good performance. But it had the power of the Merlin to make it so. The model with the greatest performance was the N.F. Mk.30. Even with wooden construction the cost of the second crewman raised normal loaded weight to 20,000 lbs. The two 1,710 hp Rolls-Royce Merlin76 liquid-cooled V-12s pushed the plane to 407 mph at 28,000 feet. Climb was on sub par to the P-38 reaching 15,000 feet in 7.5 minutes. Range with maximum external fuel was a healthy 1,700 miles. Firepower was robust with its four nose-mounted Hispano 20mms with 150 rpg. The four .303 MGs in the belly were dropped.
Mosquitos escorting the RAF bombers were somewhat successful combating German night interceptors but very effective outfitted with radar probing for intruders. The dynamic team of pilot John Cunningham and RIO C.F. Rawnsley led the night fighters with twenty victories. Their quarry was usually twin-engine bombers like the He-111, Ju-88 or Do-17. Stealthily approaching in the darkness it was usually a straightforward six o'clock intercept with deadly consequences for the enemy.
The He-219 Uhu (Owl) two-seater was a large plane with a 60 foot wingspan weighing in at nearly 25,000 lbs., but the two V-12 liquid-cooled DB 603Gs of 1,900 hp each could squeeze out a top speed of 416 mph at 22,965 ft. Climb was a modest 2,000 fpm but the service ceiling was high at 41,660 ft. Max range was 1,243 miles.
Guided by searchlights, ground and airborne radar, the 110s were very effective with Wilde Sau tactics pioneered by Hajo Hermann. Major. Heinz Wolfgang Schnaufer led the night fighters with 121 victories.
A huge variety of field modifications of armament to the 110/210/410 existed but the basic 110C-4 day fighter and G-4 night fighter had two MG FF 20mms and four 7.9mm MG 17s with the G-4/R3 three-seater mounting two Mk 108 30mms and two MG 151 20mms. The /R3 weighed in at 20,700 lbs loaded and could travel 1,305 miles with maximum fuel. A top speed of 342 mph was generated from a pair of 1,475 hp Daimler-Benz DB 605 V-12 liquid-cooled engines. It could climb to 18,000 feet in 7.9 minutes and the ceiling was 26,000 feet. 6,257 110s of all types were built.
The Toryu, known as the "Nick" to the Allies, and later was used in the bomber attack role. It was certainly not in the class of the P-38. The Toryu had a pair of Mitsubishi Ha.102 Type 1 14-cylinder radial air-cooled engines rated for only 1,080 each making for a modest 340 mph at 22,965 feet. The climb to 16,405 feet was 6.1 minutes. Normal weight was a light 11,631 lbs. and range was 1,243 miles.
Armament was heavy. Initially one 37mm Ho-203 and a 20mm Ho-5 in the nose with a 12.92 Type 98 machine gun in back. The KI.45 KAI-Hei had a second Ho-5 in the nose and the KAIc had the double 20mm oblique angle arrangement that most of the above-mentioned Germans machines used called "Schräge Musik." Schräge, with an umlaut above the "a," meaning slant or slope. The type was used in night fighting roles like their German counterparts.
The KI.46 "Dinah" was a slick two-seat design. Early models were relegated to reconnaissance duties but with the KI.46III-KAI it obtained the forward armament of two Ho-5s and one Ho-203 firing at a 30-degree angle. The excellent Mitsubishi Ha.112-II 14-cylinder air-cooled radials with 1,500 hp made the plane fast with 391 mph seen at 19,685 feet. (See "Gun Kills II" telling of Mitchell Harris's Hellcat pursuit and victory over a Dinah) The sleek plane had a ceiling of 34,200 feet and could climb to 26,250 feet in eighteen minutes. Weight was 13,730 lbs loaded giving a range of 1,305 miles.
Only one fighter above has a single pilot, the P-38, though the end-of-war DeHavilland Hornet single-seater, with a 472 mph top speed, was potentially a winner. If the P-47 is considered big with a 42 foot wingspan where most single-engine pursuit planes had about a 36-37 foot span, then these twins were huge.
Dogfighting WWI style was not much seen in WWII and tactics allowed these planes to carry out their intended roles well. But if there was a hairball fight with many attacking single-engine fighters only the P-38 and, to some extent, the Mosquito would have been able to hold their own in the maneuverability department. Their pilots did not engage in roundy-round fights. All the other planes found it necessary to add a rear defense gunner to assist their survival and that tells something. Only the P-38 was a true interceptor/fighter as we know it. No other twin approached its long-range ability either. The rest were ultimately used at night where their strengths served them and their weaknesses were masked.
Slim, single-engine, single-seat designs with later high output engines were more effective in that role and cost less to produce and maintain. Twins offered a larger target, and while many pilots were saved by having a second engine to limp home on, performance on one motor in combat was a non-event. A Mosquito pilot was once quoted to say, "One runs out of engines so quickly!"
It's one thing to lob rockets and heavy cannon shells at static bomber boxes and quite another to dice it up with their maneuverable escorts. Dark of night gave them the sanctity to exist at all for they never survived in the same percentages as did single-engine fighters in daylight.
I heard ace Robin Olds once say about the F4 Phantom, "Put big enough engines on a brick and it will go fast too."
Today we have quite a few Mach 2 bricks flying but they have the superb aerodynamics and enough power to outperform any single-engine aggressors except in the area of maneuverability. They no longer hide in darkness as their WWII predecessors did. The twin-engine fighters of those days long ago were a concept whose time had not yet come. The twin's time is here.
Green, William
Fighters Vols. 1-2-3-4
Doubleday& Co., NY, 1960-62
Green, William & Swanborough, Gordon
The Complete Book of Fighters
Smithmark Publishers Inc., NY, 1994
Rawnsley, C.F.
Night Fighter
Ballantine Books, NY,1957
Sharpe, Michael, Scutts, Jerry & March, Dan
Aircraft of World War II
PRC Publishing Ltd, London, 1999
Printer Friendly
Twin-Engine Fighters
by Jim "Twitch" TittleArticle Type: History
Article Date: May 10, 2001
An Idea Before Its Time
 |
| P-38H |
The concept was always good from an engineering standpoint. Mount two engines on an airframe for better performance. This was true in the thirties when aircraft engines were more modest in output. But aside from longer range, due to the increased fuel storage capabilities, twins never outclassed singles. Some were total failures.
Sure, nose mounted guns gave a superior centerline firing axis but many single-engine fighters mounted guns on the fuselage for the same effect. Of course examples such as the excellent Mosquito and P-38 come to mind. But what else? Let's look at WWII's twin-engine fighters in detail for some comparisons.
Two Stand Out
The Lockheed P-38 Lightning stands alone as the most successful twin in the war, and that applies only to the Pacific Theatre of Operations really. There America's top aces excelled in the big plane against the Japanese. But I've learned one thing in my lifetime of studying WWII in the air—good pilots took any plane given them and used its strong points. Urben Drew, who racked up seven victories in the ETO flying P-51s, including two Me 262s told me, "There are pilots who fly fighters and fighters who fly planes." This defines aces to this author in one sentence.When H.L. Hibbard's design team began design concepts for the Army Air Corp's required high-altitude, high-speed interceptor they adopted the configuration we all recognize today in the P-38. No single engine concept in the late thirties had the power to meet the specifications so the twin-boom layout evolved.
The P-38-J-25-LO was the best example produced in quantity beginning in 1943 with the 1-LO. Two turbo-supercharged Allison V-1710-89/91 V-12 liquid cooled engines of 1,425 hp each gave the plane a top speed of 414 mph at 25,000 feet. The 17,500 lb plane could climb to 20,000 feet in seven minutes with a ceiling of 44,000 feet. The range with maximum external fuel was long at 2,260 miles, though this would later be duplicated by the P-51. In fact the speed performance figures could be matched or excelled by many single-engine Luftwaffe fighters.
Armament was strong with four Browning .50s with 500 rpg and a Hispano 20mm with 150 rounds. Ten rockets could be carried and up to 1,600 lbs. of bombs could be mounted.
ETO P-38s were dismal in their combat record. There was a significant amount of technical malfunction due to the damp, cold European climate. The high-altitude edge it had in the Pacific was less significant in the ETO since many German fighters had good altitude performance. When in the MTO most of the combat ended up involving low altitudes where its ability to dive was much impaired. Luftwaffe fighters were more heavily armed than their Japanese counterparts too.
In the PTO it was a totally different story where it downed more aircraft than any American plane. Perpetual good weather allowed the P-38s to roam far and wide using altitude advantage, dive speed, level speed and zoom tactics to a superior level. But would Dick Bong, Tommy McQuire and the rest have faired as well in Europe? Probably not.
The DeHavilland Mosquito two-seat fighter was derived originally from a high-performance light bomber. With the RAF handling the Reich's night bombing the "Mossie" fighter or bomber version never really competed equally with their single-engine brothers. The daylight missions that the Mosquito flew were generally against ground targets and at night it was a completely alien environment though night-fighting variants excelled.
 |
| A Mossie Today |
Owning partly to its wonderful wooden airframe of lightweight and high strength, the Mosquito had good performance. But it had the power of the Merlin to make it so. The model with the greatest performance was the N.F. Mk.30. Even with wooden construction the cost of the second crewman raised normal loaded weight to 20,000 lbs. The two 1,710 hp Rolls-Royce Merlin76 liquid-cooled V-12s pushed the plane to 407 mph at 28,000 feet. Climb was on sub par to the P-38 reaching 15,000 feet in 7.5 minutes. Range with maximum external fuel was a healthy 1,700 miles. Firepower was robust with its four nose-mounted Hispano 20mms with 150 rpg. The four .303 MGs in the belly were dropped.
Mosquitos escorting the RAF bombers were somewhat successful combating German night interceptors but very effective outfitted with radar probing for intruders. The dynamic team of pilot John Cunningham and RIO C.F. Rawnsley led the night fighters with twenty victories. Their quarry was usually twin-engine bombers like the He-111, Ju-88 or Do-17. Stealthily approaching in the darkness it was usually a straightforward six o'clock intercept with deadly consequences for the enemy.
Promises Unfulfilled
The big debacle of the Battle of Britain was the Bf-110. Conceived as a long-range escort fighter, the 110 ended up needing Bf-109 escorts of their own on most occasions. The progeny of the poor Me-210 (356 built) but better Me-410 (113 built) never fulfilled any potential other than night fighting or bomber attack. Sharing the daytime sky with superb RAF and USAAF fighters proved disastrous for these twins. Thunderbolt pilots dubbed them "meat on the table," owing to the easy shoot down probability when encountered. 110s, later joined by the few (268 built) He-219s owned the dark skies over Germany at night however.The He-219 Uhu (Owl) two-seater was a large plane with a 60 foot wingspan weighing in at nearly 25,000 lbs., but the two V-12 liquid-cooled DB 603Gs of 1,900 hp each could squeeze out a top speed of 416 mph at 22,965 ft. Climb was a modest 2,000 fpm but the service ceiling was high at 41,660 ft. Max range was 1,243 miles.
Guided by searchlights, ground and airborne radar, the 110s were very effective with Wilde Sau tactics pioneered by Hajo Hermann. Major. Heinz Wolfgang Schnaufer led the night fighters with 121 victories.
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| 110 Over Dover 1941 |
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| A 410 In UK Museum |
A huge variety of field modifications of armament to the 110/210/410 existed but the basic 110C-4 day fighter and G-4 night fighter had two MG FF 20mms and four 7.9mm MG 17s with the G-4/R3 three-seater mounting two Mk 108 30mms and two MG 151 20mms. The /R3 weighed in at 20,700 lbs loaded and could travel 1,305 miles with maximum fuel. A top speed of 342 mph was generated from a pair of 1,475 hp Daimler-Benz DB 605 V-12 liquid-cooled engines. It could climb to 18,000 feet in 7.9 minutes and the ceiling was 26,000 feet. 6,257 110s of all types were built.
More Slanting Music
Back in the Pacific the two standout Japanese twins were the Kawasaki KI.45 Toryu (Dragon Killer) and the Mitsubishi KI.46.The Toryu, known as the "Nick" to the Allies, and later was used in the bomber attack role. It was certainly not in the class of the P-38. The Toryu had a pair of Mitsubishi Ha.102 Type 1 14-cylinder radial air-cooled engines rated for only 1,080 each making for a modest 340 mph at 22,965 feet. The climb to 16,405 feet was 6.1 minutes. Normal weight was a light 11,631 lbs. and range was 1,243 miles.
Armament was heavy. Initially one 37mm Ho-203 and a 20mm Ho-5 in the nose with a 12.92 Type 98 machine gun in back. The KI.45 KAI-Hei had a second Ho-5 in the nose and the KAIc had the double 20mm oblique angle arrangement that most of the above-mentioned Germans machines used called "Schräge Musik." Schräge, with an umlaut above the "a," meaning slant or slope. The type was used in night fighting roles like their German counterparts.
 |
| Three KI.45-KAI-Hei 1945 |
The KI.46 "Dinah" was a slick two-seat design. Early models were relegated to reconnaissance duties but with the KI.46III-KAI it obtained the forward armament of two Ho-5s and one Ho-203 firing at a 30-degree angle. The excellent Mitsubishi Ha.112-II 14-cylinder air-cooled radials with 1,500 hp made the plane fast with 391 mph seen at 19,685 feet. (See "Gun Kills II" telling of Mitchell Harris's Hellcat pursuit and victory over a Dinah) The sleek plane had a ceiling of 34,200 feet and could climb to 26,250 feet in eighteen minutes. Weight was 13,730 lbs loaded giving a range of 1,305 miles.
 |
| KI.46-II Recon Version Today In The UK |
The Bottom Line
All of the above mentioned twin-engine aircraft had generally the same wingspan of around 50 feet except the He-219 at 60 feet. There were others like the excellent Pe-2 ground support craft, the huge P-61 and various bombers transformed to the heavy fighter role, but these planes remain the best performing of the fighter category. Their larger airframes and dual engines allowed them to perform duties and retain acceptable maneuverability that planes like the P-61 and Ju-88 fighters with 65-66 foot wingspans could not.Only one fighter above has a single pilot, the P-38, though the end-of-war DeHavilland Hornet single-seater, with a 472 mph top speed, was potentially a winner. If the P-47 is considered big with a 42 foot wingspan where most single-engine pursuit planes had about a 36-37 foot span, then these twins were huge.
Dogfighting WWI style was not much seen in WWII and tactics allowed these planes to carry out their intended roles well. But if there was a hairball fight with many attacking single-engine fighters only the P-38 and, to some extent, the Mosquito would have been able to hold their own in the maneuverability department. Their pilots did not engage in roundy-round fights. All the other planes found it necessary to add a rear defense gunner to assist their survival and that tells something. Only the P-38 was a true interceptor/fighter as we know it. No other twin approached its long-range ability either. The rest were ultimately used at night where their strengths served them and their weaknesses were masked.
Slim, single-engine, single-seat designs with later high output engines were more effective in that role and cost less to produce and maintain. Twins offered a larger target, and while many pilots were saved by having a second engine to limp home on, performance on one motor in combat was a non-event. A Mosquito pilot was once quoted to say, "One runs out of engines so quickly!"
It's one thing to lob rockets and heavy cannon shells at static bomber boxes and quite another to dice it up with their maneuverable escorts. Dark of night gave them the sanctity to exist at all for they never survived in the same percentages as did single-engine fighters in daylight.
The Idea Evolved
Today the most notable twin-engine fighters have a second crewman not with a gun but with electronic equipment. The F-16 Falcon pretty much stands alone as the only notable modern single-engine/single-seat fighter. In anything reminiscent of a dogfight the F-16 would be dominant against much larger, heavier planes with two blowers. But given the long-range avionics and weapons of today, the big twin-engine twin-seater might not often allow the F-16 to use its trump card of maneuverability during close-in combat.I heard ace Robin Olds once say about the F4 Phantom, "Put big enough engines on a brick and it will go fast too."
Today we have quite a few Mach 2 bricks flying but they have the superb aerodynamics and enough power to outperform any single-engine aggressors except in the area of maneuverability. They no longer hide in darkness as their WWII predecessors did. The twin-engine fighters of those days long ago were a concept whose time had not yet come. The twin's time is here.
Bibliography
Green, William
Fighters Vols. 1-2-3-4
Doubleday& Co., NY, 1960-62
Green, William & Swanborough, Gordon
The Complete Book of Fighters
Smithmark Publishers Inc., NY, 1994
Rawnsley, C.F.
Night Fighter
Ballantine Books, NY,1957
Sharpe, Michael, Scutts, Jerry & March, Dan
Aircraft of World War II
PRC Publishing Ltd, London, 1999
Printer Friendly