Author Topic: Here's another obscure A/C (Read 285 times)

Holden McGroin · « **on:** September 08, 2002, 04:01:07 PM »

Here's another obscure A/C

palef · « **Reply #1 on:** September 08, 2002, 05:30:52 PM »

Looks like a B17 with Alison engines.

Very pleasant to look at too.

palef

SpinDoc1 · « **Reply #2 on:** September 08, 2002, 06:18:56 PM »

Wasn't that one of the planes used as personal transport for the President or Eisenhower or Marshall? I read it in a book somewhere but it was a B17 made nice and shiny as their personal escort.

Jason

Sever · « **Reply #3 on:** September 08, 2002, 06:37:46 PM »

Very beautiful. Makes it look like a different aircraft.

Chairboy · « **Reply #4 on:** September 08, 2002, 07:07:56 PM »

B-17E modified to use the Allison V-1710-89?

Holden McGroin · « **Reply #5 on:** September 08, 2002, 07:27:11 PM »

Designed to fight its way to Berlin...

Shiva · « **Reply #6 on:** September 08, 2002, 08:22:18 PM »

That appears to be the XB-38.

As part of its participation in the Boeing-Vega-Douglas manufacturing pool for the Fortress, the Vega division of Lockheed had been requested by the USAAF to explore the feasibility of adapting the basic B-17E airframe to the 1425 hp Allison V-1710-89 liquid-cooled V-12 engine.

Negotiations for development of the new design, known as Vega Model V-134-1, began in March of 1942 and a contract was signed on July 10. The project was considered sufficiently different from the stock B-17E that a new series number was assigned -- XB-38. The ninth production B-17E (serial number 41-2401) had been turned over to Vega for study during the initial formation of the B.V.D. manufacturing pool, and this plane was selected for the first XB-38 conversion.

The basic airframe of the XB-38 was essentially that of the B-17E, with a few revisions necessitated by the installation of the new powerplants. For example, the oil coolers of the B-17E were mounted in the leading edges of the wings, but they were moved to positions underneath the propellers in the XB-38. Also, the coolant radiators for the Allisons were mounted in the wing leading edges between each pair of engine nacelles.

The XB-38 made its first flight on May 19, 1943. As a result of the increased power of the Allison engines, the XB-38 was slightly faster than its radial-powered B-17E counterpart. However, the XB-38 prototype was destroyed on June 16, 1943 as a result of an engine fire which could not be extinguished, and a full comparison with the Wright-powered B-17E could never be made. In any case, the performance improvement offered by the XB-38 was only marginal, and since the liquid-cooled Allisons were in great demand for the P-38 Lightning and P-40 Warhawk fighters, the USAAF decided to abandon further work on the XB-38, and plans for two additional XB-38 conversions were cancelled.

Specification of Boeing XB-38:

Four Allison V-1710-89 liquid-cooled V-12 engines, rated at 1425 hp at 25,000 feet.

Maximum speed 327 mph at 25,000 feet.

Cruising speed 226 mph.

Service ceiling 29,700 feet.

Range 2400 miles with 3000 pounds of bombs, 1900 miles with 6000 pounds of bombs.

Maximum range 3600 miles.

Dimensions: Wingspan 103 feet 9 3/8 inches, length 74 feet 0 inches, height 19 feet 2 inches, wing area 1420 square feet.

Weights: 34,748 pounds empty, 56,00 pounds gross, 64,000 pounds maximum.

Armament was the same as that of the standard B-17E, namely one 0.30-inch machine gun which could be mounted on any one of six ball-and-socket mounts in the extreme nose, one Sperry No. 645473E power turret in the dorsal position with two 0.50 Browning M2 machine guns with 500 rounds per gun, a remotely-controlled power turret in ventral position with two 0.50-inch Browning machine guns with 500 rounds per gun, one 0.50-inch Browning M2 machine gun is each of the two waist windows, 400 rounds per gun, and two 0.50-inch M2 Browning machine guns in the tail position, with 500 rounds per gun.

Holden McGroin · « **Reply #7 on:** September 09, 2002, 11:50:50 AM »

My information says B 34, a B-17 with Allison V 3420, "W" 24 Cylinder engine. (see picture in previous) Basically (2) 1710's sharing a common crankcase. Two crankshafts feed a gearbox to turn one prop.

B-34 was a machine gun platform to escort B-17's into Germany. When P-51's cameon line, the design was abandoned, and the engines used elswhere.

palef · « **Reply #8 on:** September 09, 2002, 04:50:16 PM »

Boeing didn't build a B34. The B34 was made by Lockheed and was called Ventura IIA by the RAF, and RNZAF. It differed from the Ventura in Commonwealth service by having US armament options fitted.

Vega (A division of Lockheed) actually did the feasibility study and construction of the XB38 which featured the engine installation: "Four Allison V-1710-89 liquid-cooled V-12 engines, rated at 1425 hp at 25,000 feet." in a B17E airframe.

Sources:

1. Flying Fortress, Edward Jablonski, Doubleday, 1965.

2. Famous Bombers of the Second World War, Volume One, William Green, Doubleday, 1959.

3. Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.

4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.

5. Lockheed Aircraft Since 1913, Rene J. Francillon, Naval Institute Press, 1987.

6. Boeing B-17E and F Flying Fortress, Charles D. Thompson, Profile Publications, 1966.

7. American Combat Planes, Ray Wagner, Third Edition, Doubleday, 1982.

8. Jane's Fighting Aircraft of World War II, Military Press, 1989.

The W24 engine was used in a YB-29 Airframe and redesiganted XB39

The first YB-29 (41-36954) was turned over to General Motors for installation of liquid-cooled Allison V-3420 engines and further tests. The converted aircraft was later redesignated XB-39. The V-3420 engine was essentially a pair of Allison V-1710 twelve-cylinder liquid-cooled Vee engines coupled to a single propeller shaft. Normal output was 2100 hp at 25,000 feet. Aircraft speed increased to 405 mph at 35,000 feet, but the improvement in performance was not considered sufficient to justify production.

Sources:

1. Warbird History--B-29 Superfortress, Chester Marshall, Motorbooks International, 1993.

2. The Boeing B-29 Superfortress, Mich Mayborn, Aircraft in Profile, Doubleday, 1969.

3. B-29 Superfortress, John Pimlott, Gallery Books, 1980.

4. Famous Bombers of the Second World War, William Green, Doubleday, 1960.

5. Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.

6. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian Institution Press, 1989.

7. Jane's Fighting Aircraft of World War II, Bill Gunston, Military Press, 1989.

8. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.

Sorry about the huge message, but the very sleek aircraft in your original post intrigued me so I did some research.

palef

palef · « **Reply #9 on:** September 09, 2002, 05:14:07 PM »

Here's a picture of the XB-39 "Spirit of Lincoln"