The best 2-engined bomber in 1944-45?

[wuzak]

From a similar discussion on the www.warbirds.com forum some time ago:

It was best summed up in the book 'Flying Guns – World War 2: Development of Aircraft Guns, Ammunition and Installations 1933-45', in which my co-author Emmanuel Gustin wrote the following:

"Soon Mosquito bombers became a vital part of the night operations too. In early 1944 a bulged bomb bay was introduced to hold a 4000 lb 'cookie,' doubling the bomb load. The combat introduction of the high-altitude B.XVI version, which was even harder to intercept, was in March. A paper by the Ministry or Aircraft production calculated that, before the aircraft was lost, a Mosquito could be expected to drop an average of 1690 kg of bombs in 92 sorties. A Lancaster would drop 3370 kg on an average sortie, but survived on average only 28 sorties, and cost 2.8 times as much as a Mosquito. It could be concluded that the material cost per ton of bombs dropped was at least four times lower for the Mosquito than for the Lancaster. And the Mosquito had only one-fourth of the crew of the Lancaster, so its use also reduced the loss of life. Evidently, such figures are dependent on time, tactics, and circumstances, but they were nevertheless evidence that the Mosquito had advantages that had to be exploited. The "Light Night Strike Force" became an important part of Bomber Command's No.8 Group; its operations included 170 attacks on Berlin."

Tony Williams
Military gun and ammunition website: CANNON, MACHINE GUNS AND AMMUNITION

There is an interesting late-war study carried out by the RAF in the PRO files (reference AIR 2/5487, minutes of meeting held 20 April 1944 to consider future bomber needs). This was called to discuss potential super-heavy bombers, but the discussion included much questioning of the need for such planes. A mathematical proof was included of the superior efficiency of a large number of small bombers rather than a small number of big ones (unfortunately, this was before the days when digital cameras were allowed and I didn't have the patience to copy it all). However, from memory it compared the construction cost, bomb loads and survival chances of big and small bombers and demonstrated that the small, fast unarmed bomber (read: Mosquito) was a more efficient bomb delivery system than the big slow one (read: Lancaster).

Yes, the Lanc could carry the super-heavy bombs, but frankly such attacks were more effective at hitting the headlines than they were at shortening the war.

Tony Williams
Military gun and ammunition website: CANNON, MACHINE GUNS AND AMMUNITION

 

[oldcrowcv63]

That "primitive" was a reaction to a post from Siegfried.

I fought the NVA, I never considered them primitive.

Just to ice the cake on this point, the Vietnamese SAM: SA-2 acquistion, tracking and control was by upgraded FAN SONG RADAR systems which the most advanced electronic countermeasures aircraft in existence for the time, the USN EA-6B, at that time, had very limited capability to defeat. I don't know whether the USAF Wild Weasel A/C had better capability in that regard, but the USN was seriously challenged.

 

[oldcrowcv63]

Starting in 1944, the light and medium two engine bomber was in transition. Except perhaps in the PTO, dive bombing was fading in popularity and high altitude bombing was not providing the needed accuracy for tactical support. Low altitude was the coming answer and a move toward the attack aircraft.

Planes like the A-26 and A-1 were valuable for their endurance and stores capability over the battlefield and led to the development of the A-10, which is probably the closest thing to a two engine bomber today. The F-117 did give a short breath. Fighter bombers are now the way.

One twin engine bomber/attack aircraft that does NOT qualify for entrance in this thread but retained design features making it suitable for classic dive bombing past the Vietnam era is the Grumman A-6 Intruder which initially sported fuselage mounted dive (speed) brakes, ultimately forsaken in favor of wing tip-mounted speed-brakes beneficial in a number of flight regimes, including landing. A Vietnam era A-6 B/N reports that 95% of his mission ordnance deliveries were in the dive bombing mode. I suspect this may be a cultural departure wrt to USAF emphasis (or deemphasis). Dive bombing was even occasionally practiced by USN pilots in tactical aircraft that never carried ordnance. I believe the USN carried dive bombing as a preferred method of delivery beyond the time that the USAF did and into the modern era, although I'd guess USAF fighter bombers may have used a DB-like delivery profile on occasion as well.

Post script, as for my choice of a preferred twin engined end-war period bomber, I'd say A-26 with the Mossy a close second
Reason? They were designed by Ed Heineman and Geoffrey DeHavilland, respectively. That's almost all I need to know. The performance details provide validation (in my mind at least).

 

[pbfoot]

Just finished rereading Alan Macnutts Altimeter Rising and he probably has to be 1 of the high time Mosquito pilots having flown them post war on survey work around most of the world and he also flew the A26 as a FireBomber , he preferred the the A26 as a flyer and platform and was regurlay hauling 8000lbs of fire retardent in it, He also did a lot of work in P38`s loved the contra rotating props but found they were more labour intensive maintainence wise then the Mosquito but far more pilot friendly. Some great stories in this book such as flying a P38 for Chilean survey along border with Argentina and the Argentinians at the time tried to intercept him but they had nothing to get to his altitude he buggered off. He was an AME as well and flew as an instrument check pilot for the MOT .
Great book on flying

 

[renrich]

If my memory is OK I seem to remember that the B26 served well in the Korean War and that the North Koreans and South Koreans were both about the same size and North Korea invaded South Korea not to liberate then but to conquer them for their own purposes. Thanks be we along with our allies stood in the way.

 

[MacArther]

It hasn't been mentioned...but what about a Black Cat style Catalina for patrol, night attack, and harassment duties?

 

[pbfoot]

It hasn't been mentioned...but what about a Black Cat style Catalina for patrol, night attack, and harassment duties?

What is a Black Cat is it different then a normal PBY5 ,

 

[parsifal]

A price that must be paid if you want to hit the target with iron bombs. That's why the Me-410 and Ju-88 could dive bomb.

....you forgot to add...with less accuracy than the mosquito operating at low level, and using an attack method that rendered the aircraft highly vulnerable

 

[MacArther]

What is a Black Cat is it different then a normal PBY5 ,

If I tried to explain it, I know I'd screw up. Under the Night Attack and Naval Interdiction is the Black Cat section. Basically, the Cats were modified to carry more guns (like 20mm bow guns), we painted black for night operations, and carried bombs both on the wings, and grenade sized munitions in the body dropped by the crew. The rest is better read from the site (even if it is Wiki).
http://en.wikipedia.org/wiki/Consolidated_PBY_Catalina#Night_attack_and_naval_interdiction

 

[pbfoot]

If I tried to explain it, I know I'd screw up. Under the Night Attack and Naval Interdiction is the Black Cat section. Basically, the Cats were modified to carry more guns (like 20mm bow guns), we painted black for night operations, and carried bombs both on the wings, and grenade sized munitions in the body dropped by the crew. The rest is better read from the site (even if it is Wiki).
Consolidated PBY Catalina - Wikipedia, the free encyclopedia

so not much different save the 20mm and the hand dropped grenades so Catalina or Canso depending on builder

 

[wuzak]

Just finished rereading Alan Macnutts Altimeter Rising and he probably has to be 1 of the high time Mosquito pilots having flown them post war on survey work around most of the world and he also flew the A26 as a FireBomber , he preferred the the A26 as a flyer and platform and was regurlay hauling 8000lbs of fire retardent in it, He also did a lot of work in P38`s loved the contra rotating props but found they were more labour intensive maintainence wise then the Mosquito but far more pilot friendly. Some great stories in this book such as flying a P38 for Chilean survey along border with Argentina and the Argentinians at the time tried to intercept him but they had nothing to get to his altitude he buggered off. He was an AME as well and flew as an instrument check pilot for the MOT .
Great book on flying

I wonder if that was just a comfort thing for the pilot.

The Mosquito had two very noisy Merlins mounted next to the crew's ears.

Also not surprised that the A-26 could carry such a load. Once you dump the turrets and guns and any other military equipment you would have increased the lift capacity substantially.

And the A-26 was about 1/3 larger than the Mosquito.

None of which makes the A-26 a better bomber in 1944-45 than the Mosquito.

 

[pbfoot]

I wonder if that was just a comfort thing for the pilot.

The Mosquito had two very noisy Merlins mounted next to the crew's ears.

Also not surprised that the A-26 could carry such a load. Once you dump the turrets and guns and any other military equipment you would have increased the lift capacity substantially.

And the A-26 was about 1/3 larger than the Mosquito.

None of which makes the A-26 a better bomber in 1944-45 than the Mosquito.

I would think the engines would be one thing ,the Merlin didn't have the same life span in any way close to the R2800 which was still neing put into newbuild aircraft as late as the 70s , and as for the comfort that was usually the last consideration for any Brit aircraft . I've heard it mentioned more then once in humour they designed a lovely aircraft and then had to decide where to put the pilot

 

[Lucky13]

For the sake of talking, as you say 44-45....
How well the Swedish B-18 compare?

General characteristics

Crew: 3 (pilot, navigator/gunner, and bombardier)
Length: 13.23 m (43 ft 5 in)
Wingspan: 17 m (55 ft 9 in)
Height: 4.35 m (14 ft 3 in)
Wing area: 43.75 m2 (470.9 sq ft)
Empty weight: 6,100 kg (13,448 lb)
Max takeoff weight: 8,800 kg (19,401 lb)
Fuel capacity: 1,700 litres (370 imp gal; 450 US gal)
Powerplant: 2 × Daimler-Benz DB 605 inverted-vee piston engines, 1,100 kW (1,475 hp) each
Performance

Maximum speed: 575 km/h (357 mph; 310 kn)
Range: 2,600 km (1,616 mi; 1,404 nmi)
Service ceiling: 9,800 m (32,152 ft)
Armament


Guns: one 7.92mm fixed forwards-firing gun in wing root; two 13.2mm defensive guns.
Rockets: 8 air-to-surface rockets on underwing stubs
Bombs: 1,500 kilograms (3,300 lb) in internal bay

 

[Siegfried]

For the sake of talking, as you say 44-45....
How well the Swedish B-18 compare?

General characteristics

Crew: 3 (pilot, navigator/gunner, and bombardier)
Length: 13.23 m (43 ft 5 in)
Wingspan: 17 m (55 ft 9 in)
Height: 4.35 m (14 ft 3 in)
Wing area: 43.75 m2 (470.9 sq ft)
Empty weight: 6,100 kg (13,448 lb)
Max takeoff weight: 8,800 kg (19,401 lb)
Fuel capacity: 1,700 litres (370 imp gal; 450 US gal)
Powerplant: 2 × Daimler-Benz DB 605 inverted-vee piston engines, 1,100 kW (1,475 hp) each
Performance

Maximum speed: 575 km/h (357 mph; 310 kn)
Range: 2,600 km (1,616 mi; 1,404 nmi)
Service ceiling: 9,800 m (32,152 ft)
Armament


Guns: one 7.92mm fixed forwards-firing gun in wing root; two 13.2mm defensive guns.
Rockets: 8 air-to-surface rockets on underwing stubs
Bombs: 1,500 kilograms (3,300 lb) in internal bay

Certainly a usefull machine in 1944 though it would need to improve by 1945 to be competitive with the best allied and axis aircraft.

I've heard that the DB605A when run of 100/130 fuel in swedish service could produce 1700hp? Any info on this?

 

[Lucky13]

Worth looking into mate! What would that do to the performance of the B-18, another 450hp on those engines (together)?

 

[wuzak]

Worth looking into mate! What would that do to the performance of the B-18, another 450hp on those engines (together)?

1700hp DB605s will give a maximum speed of 376mph/606km/h.

2040hp will allow it to crack 400mph/644km/h.

2360hp would be required to match the Mosquito's B.XVI's maximum (unloaded) of around 420mph/675km/h.

 

[Shortround6]

I am not sure the Swedes ever rated the DB605 over 1475hp or PS at take off. It was rated at 1575hp at 7000ft and 1250hp at 19,000ft. fuel was 91/96 octane. Figures are in several editions of "Aircraft Engines of the World" no higher numbers are listed. The Swedes may have been build the 605 with the original smaller supercharger. In peace time they may have been more interested in engine life than peak performance and if combat had occurred they may have pushed the engines.

 

[Siegfried]

Worth looking into mate! What would that do to the performance of the B-18, another 450hp on those engines (together)?

Using a cube root law (1700/1475)^0.333 = 1.048. That equates to a speed increase from 357 to 375. The calculation is somewhat conservative as induced drag does not increase while the increased jet thrust only obeys a square root law. However I did not include whether the supercharger was maxed out 1.7 ata boost at the maximum speed altitude needed to achieve this. The effect of the extra power might then be to sustain maximum speed down to much lower altitudes, including at sea level. This is likely where the B18 would be opperating anyway. Certainly with the 2000hp DB605DCM engine at least 395mph would be possible while the aircraft would be able to cruise in at 357mph.

Shortround6, the DB605AM engine could clear 1700hp on B4+MW50, this was essentially a DB605A with water methanol injection added and retained the orginal supercharger. Around the same time that the Me 109G6AM was entering service around March 1944 the Me 109G6ASM was entering service with an enlarged supercharger variant (DB605ASM). However the non enlarged Me 109G6AM was actually faster at low altitude due to better matching of the supercharger for low altitude work.

The swedes would have had better fuel and likely better sparking plugs etc.

 

[FLYBOYJ]

The calculation is somewhat conservative as induced drag does not increase while the increased jet thrust only obeys a square root law. However I did not include whether the supercharger was maxed out 1.7 ata boost at the maximum speed altitude needed to achieve this. The effect of the extra power might then be to sustain maximum speed down to much lower altitudes, including at sea level. This is likely where the B18 would be opperating anyway. Certainly with the 2000hp DB605DCM engine at least 395mph would be possible while the aircraft would be able to cruise in at 357mph.

I think you have a flaw there as induced drag will increase with speed and if the airframe remains unmodified with any parasitic producing items on the aircraft (antennas, scoops, etc.) will increase drag as well, increasing parasitic drag and in the end total drag. How about the extra weight of the engine?

The swedes would have had better fuel and likely better sparking plugs etc.

I could understand fuel, but why spark plugs?

 

[Siegfried]

Allied aeroengine engineers regarded the germans somewhat lagging in spark plug or ignition consciousness and development. There is a book on this "the vital spark aero engine spark plug development" of course allied engine technology was extremely agressive on the spark plugs (rich mixtures and lack of fuel injection). The plug has to keep cool enough to prevent pre-ignition but also able to remain clear of fouling and create a potent spark.

overhead camshaft | pdf archive | piston-encine progress | 1945 | 2398 | Flight Archive

The engine is no heavier, maybe 15kg for the AS engine with the bigger supercharger.