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GOT: Douglas XBTD and XTBD

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#1 Romantic Technofreak

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Posted 09 May 2008 - 11:20 PM

Hi friends, admittedly it happens that I get confused about US Navy aircraft designations. Normally, there is no big trouble in this, but concerning these two aircraft here, it is serious. They names may look the same, and if you don't concentrate, you find yourself in aerial Tumbolia (the country where the light of your bulbs shines when they are switched off and your hiccups dwell when you have none...).

Unanimously, we speak about two Douglas aircraft. But changing two designation letters makes a crucial difference: XBTD and the XTBD, got it? And it gets even worse when the designations change during the development time of the project. In order of appearance, but separated by type identity, we have:

1) XSB2D-1, XBTD-1, BTD-1, XBT2D-1, XBT2D-1Q, BT2D-1, AD-1. These are called "Destroyer", "Dauntless II" or "Skyraider".

2) VTB, TB2D, XTB2D-1, XTB2D. This one is called "Skypirate".

If you look exactly on our friend Greg's obscurities list, you find he only has #2, the "Skypirate", on it. But I think #1 matches as obscurity as well, and to end this confusion I described above, I thought to gather them in one and the same GOT topic. I am sure Greg will not object that and I hope you don't either.


Pictures were all improved a bit using XnView.



XBTD


The text is from American military aircraft doyen Joe Baugher, you don't need to click that link, for readability and insertion of pictures it is copied 1:1.

http://www.joebaughe...ck/newa1_1.html



Throughout much of the Second World War, US Navy carrier-based squadrons were equipped with two classes of bombers--the two seat scout bombers which equipped VS and VB squadrons and the three-seat torpedo bombers which equipped VT squadrons. When the war in the Pacific began, the Douglas SBD Dauntless and the Douglas TBD Devastator were the primary aircraft which filled these roles. The TBD was not very successful, but the SBD Dauntless gave an outstanding performance at the Battle of Midway and is generally rated as one of the best dive bombers of the war.

As the war progressed, the SBD Dauntless and the TBD Devastator were gradually supplanted in Navy service by the Curtiss SB2C Helldiver and the Grumman/General Aviation TBF/TBM Avenger. Douglas was faced with a situation in which its products were being displaced from Navy carrier decks by other manufacturer's aircraft.

Douglas attempted to get back in the game by introducing two new types, the XSB2D-1 Destroyer two seat scout bomber and the three-seat XTB2D-1 Skypirate torpedo bomber. Prototypes of both were ordered during 1943.

The XSB2D-1 was intended as the successor to the SBD Dauntless and was powered by a 2300 Hp Wright R-3350-14 engine. It had an inverted gull wing. The XSB2D-1 was equipped with a tricycle undercarriage, rather unusual at the time for a carrier-based aircraft. It was equipped with a heavy defensive armament consisting of two remotely-controlled turrets, one in the dorsal position just ahead of the vertical tail and the other in the ventral position.

The book cover from Bob Kowalski and Steve Ginter shows how the XSB2D-1 would have looked:
nf30.jpg

The XTB2D was designed as a replacement for the TBM Avenger. Like the SB2D, it had a tricycle undercarriage, but it was a much larger aircraft and was powered by a 28-cylinder Pratt & Whitney R-4360 radial engine driving contrarotating propellers. Proposed defensive armament included a power-operated dorsal turret containing two 0.50-inch machine guns and a single 0.50-8nch flexible gun in the ventral position.

However, by this time in the war the US Navy had established almost complete air superiority over most of its areas of operation in the Pacific, and it was thought that defensive armament on its bombers was no longer needed. The Navy soon began to have second thoughts about multi-seat bombers and began to consider the development of a single-seat aircraft which could fulfill both dive-bombing and torpedo bombing roles. To meet this need, the Navy introduced a new category of aircraft, termed BT, where BT stood for Bombing, Torpedo.

To meet this new need, Douglas adapted its XSB2D-1 into a single seat aircraft designated XBTD-1. The two remotely controlled turrets were removed and the gunner's seat was eliminated. Two wing-mounted 20-mm cannon were added, the internal bomb bay was enlarged, and fuel capacity was increased. Several other manufacturers also submitted prototypes--the Curtiss XBTC-1, the Kaiser-Fleetwings XBTK-1, and the Martin XBTM-1.

Although 623 BTD-1s were ordered in early 1944, the Navy changed its mind in July of 1944 and decided to discontinue the BTD-1 program and substitute batches of BTCs, BTK's and BTMs in its place. Of these, only the Martin BTM was destined to enter service, and was produced in only relatively small numbers as the AM-1 Mauler.

Undeterred by the cancellation of its BTD program, Douglas went to work on a completely new aircraft to meet the Bomber-Torpedo requirement. The Douglas team was lead by Chief Engineer Ed Heinemann, Chief Designer Leo Devlin, and Chief Aerodynamicist Gene Root. The design that emerged owed little to the earlier BTD. It had low-mounted, straight-tapered wings which folded directly upward for stowage. Large dive brakes were installed on each side of the fuselage behind the wing trailing edge and underneath the rear fuselage. The main undercarriage members retracted backwards and rotated through 90 degrees into wells in the lower wing. The rear of the fuselage had a retractable tailwheel and arrester hook. The engine was to be a 2500 hp Wright R-3350-24 eighteen-cylinder radial. The single pilot was seated underneath a bubble canopy which slid to the rear. The offensive weapons load was to be carried on racks underneath the fuselage and under the wings, no internal weapons bay being provided. There was no provision for any defensive armament.

The Navy was sufficiently interested in the project that they diverted funds originally slated to the BTD-1 to purchase 15 examples under the designation XBT2D-1. This order was increased to 25 on July 21, 1944.

In order to get the first two XBT2D-1s into the air as quickly as possible, they were both fitted with the main undercarriage struts and wheels of the Vought F4U-1. In addition, due to the late availability of the R-3350-24W, the first four XBT2D-1s had the less-powerful 2300 hp R-3350-8. The aircraft was tentatively given the name Dauntless II.

The first XBT2D-1 (Bu No 09085) made its maiden flight from Mines Field, CA on March 18, 1945, with Douglas test pilot LaVerne Brown at the control. The plane was delivered to the Navy Proving Ground at Patuxent River, Maryland. Flight tests were satisfactory, and the performance was excellent, with no signicant flaws being found.

How it looked in summer 1945:
DouglasBTD-1Destroyer2.jpg

On May 5, 1945, a Letter of Intent for 548 production BT2D-1s was signed. Following V-J Day, the order was reduced to 377 and then further to 277.

The second aircraft flew on May 8, 1945. It was used for flight vibration tests of the propeller. In June, it was sent to the NACA wind tunnel at NAS Moffett Field, CA for full-scale wind tunnel tests. Aircraft number 3 (BuNo 09087) was returned to the factory in July of 1945 for the incorporation of full strength catapulting and arresting provisions. It did not fly until Aug 17, 1945.

Aircraft number 4 (BuNo 09088) flew for the first time on October 6, 1945.

25 XBT2D-1s were built. the first four were powered by the 2300 hp Wright R-3350-8, with one being tested with a large propeller spinner. All other aircraft were powered by the 2500 hp R-3350-24W that had originally been specified. The aircraft were armed with two wing-mounted 20-mm cannon. There were three large pylons for externally-carried offensive armament, one underneath the fuselage centerline, and one underneath each inboard wing panel. In addition, there were twelve small racks under the outer wings.

In late 1945, two XBT2D-1s (BuNos 09098 and 09099) were converted by the manufacturer as prototypes for a three-seat night attack version. Positions were installed within the fuselage aft of the cockpit for a pair of radar operators, with an exit door on each side of the aircraft. A radar pod was mounted underneath the port wing and a searchlight pod underneath the starboard wing. There were no dive brakes fitted to the fuselage sides.

XBT2D-1 BuNo 09096 was converted as a prototype for a single-seat photographic reconnaissance version as XBT2D-1P.

XBT2D-1 BuNo 09109 was converted to a radar countermeasures aircraft as XBT2D-1Q.

The last XBT2D-1 (BuNo. 09109) was converted into a two-seat electronic countermeasures aircraft and redesignated XBT2D-1Q. The ECM operator's station was installed inside the fuselage. The radar pod was installed underneath the port wing, and a chaff dispenser pod was installed underneath the starboard wing.

In February of 1946, the BT2D-1 was renamed Skyraider. In April of 1946, the Navy eliminated the BT designation category, replacing it by A for Attack. The BT2D-1 was redesignated AD-1.

In the spring of 1946, a few XBT2D-1s were delivered to the Pacific Fleet Air Headquarters at NAS Alameda for service trials. These tests uncovered some serious problems with main undercarriage and wing skin failures, most of which took place when when the landing weights and landing sinking speeds were high. The aircraft's structural strength was obviously too weak to stand up to the rigors of hard carrier landings.
Serial Numbers of Douglas XBT2D-1

09085/09109 Douglas XBT2D-1
c/n 1913/1937
BuNos reassigned from cancelled SB2D-1 batch.
09098 and 09099 converted to XBT2D-1N
09096 converted to XBT2D-1P
09102 at NAS Oceana, Virginia
09109 converted to XBT2D-1Q
09107 converted to XBT2D-1W, then to XAD-1W.
09108 converted to XAD-2.


Specification of Douglas XBT2D-1

Engine: One Wright R-3350-24W Duplex Cyclone 18-cylinder air-cooled radial engine, rated at 2500 hp for takeooff, 2200 hp at 11,000 feet. Performance: Maxiumum speed 375 mph at 13,600 feet, 357 mph at sea level clean cruising speed 164 mph. Initial climb ratge 3680 feet/minute. Service ceiling 33,200 feet, Initial climb rate 3680 feet/min. Range 1430 miles carrying 1 torpedo. Weights: 10,500 pounds empty, 15,000 pounds normal loaded, 17,500 pounds maximum. Dimensions: Wingspan 50 feet 0 1/4 inches, length 39 feet 5 inches, height 9 feet, wing area 400.33 square feet. Armament: Two 20-mm cannon in the wing, 400 rpg. 3 external hard points for up to two tons of bombs, torpedoes, rockets, drop tanks, or an APS-4 radar pod.

Sources:

1. Douglas A-1 Skyraider, Robert F. Dorr, Osprey, 1989

2. McDonnell Douglas Aircraft Since 1920, Vol 1, Rene J. Francillon, Naval Institute Press, 1988

3. American Combat Planes, 3rd Edition, Ray Wagner, Doubleday, 1982.


End of Joe Baugher's original text. My standard aviation book (often quoted here, repeat on request) adds that one machine was used for to test a mixed drive by installing a Westinghouse WE-19XA jet engine. It had to be placed diagonally in the fuselage behind the cockpit and could not been used at speeds over 200 miles/h. Anyway, these two were the first jet-powered Douglas airplanes.

There is a surviving sample in the Florence Air and Missile Museum, Florence, South Carolina:

DouglasBTD-1Destroyer1.jpg
(Picture from the Aviation Enthusiast Corner)



XTBD

Text from airwar.ru, translation using the profound Babelfish online translator.


Before the beginning of World War II, the Douglas Aircraft Company was noted for by development and production of two types of the carrier-based aircraft: torpedo bomber TBD "Devastator" and dive-bomber SBD "Dauntless". However, the engineers of firm did not stop on the achievement and, in 1941, they began the development of the new aircraft XSB2D "Dauntless II". In fact, the work on this project in 1943 stop in favor for the BTD "Destroyer". This was a single-seater single-engine universal aircraft, which the navy did not employ.

Meanwhile in 1942, under the direction of Ed Heinemann and Bob Donovan, work on the project "Devastator II" began. By the way, this was not the this first attempt - in a 1939 competition the firm proposed the advanced project Douglas VTB. However, competition was won by Grumman with its XTBF "Avenger". The Douglas project of 1942, before named VTB, materialized on the paper very soon. First of all, a folding wing was provided for it (here they can mean the folding device or the inverted gull wing form as well, RT).

Rifle armament was represented by two underwing pylons of type Mk 2 (each one consisted of two 12,7- mm Browning M-2). For its own defense they were three flexible machine guns intended - two in the rotary tower Firestone 250CH-3 and one under the fuselage. Four underwing pylons were provided for the suspension of additional tanks of 1135,5 liters each, which increased the flying range of the aircraft by two times (I have to contradict, these pylons were mainly foreseen to carry the torpedos, RT). Furthermore, the project provided the installation of a radar pod APS-4 and an 28- cylinder radial engine Pratt & Whitney XR-4360-8 "Wasp Major" with the power of 3000 hp.

The original appearance is very well shown by the cover of Bob Kowalski's book. If all 4 torpedos hit, a XTBD could have sank a battleship with one sole attack:

NF36.jpg

The US Navy High Command expressed interest in the new torpedo bomber project, especially to equip the new "Midway" class aircraft carriers. For escort, it was intended to use another promising design, the fighter Boeing XF8B. Besides the opportunity of carrying and launching torpedos, the aircraft had to be suitable for bombardment and reconnaissance, thus becoming a sufficiently universal machine.

On 31 October, 1943, four days after the launching of the first sample of the "Midway" class aircraft carrier - servicemen signed a contract of building two prototypes. These machines obtained the serial numbers BuNo 36933 and 36934, type designation TB2D and official name "Skypirate". However, the first prototype XTB2D-1 rose into air not before 13 March, 1945, (on the basis of other sources - during February). In summer the same year the second copy was finished, which had a 58 cm longer fuselage. None of the aircraft not was armed.

Basic forces of the Japanese navy were already destroyed at the beginning of 1945 and there was no more need for the new aircraft of category XTB2D. Therefore the order for 23 series machines was abolished, and the flight tests of two prototypes stopped. In the end of 1948 these prototypes were sent to scrap. "Skypirate" was the largest single-engined carrier-based aircraft developed in America in the years of World War II. On the wingspan and starting masses this aircraft exceeded even an average twin-engined North American B -25B "Mitchell"- the largest aircraft which took off from the deck of an aircraft carrier.

Pictures from airwar.ru:

XTB2D-11.jpg

XTB2D-12.jpg

XTB2D-13.jpg

XTB2D-14.jpg

XTB2D-15.jpg
(Surely every housewife's dream of an effective parsley chopper... :D)

The picture from wikimedia shows a propeller hub was foreseen:
TB2D_Skypiratewikimedia.jpg

Sources given by airwar.ru:

Michail Jirokhov: #1058;orpedonossets TB2D Skypirate
Naval Fighters. Bob Kowalski: Douglas XTB2D-1 Skypirate
Krzysztof Zalewski: Lotnictwo Wojskowe. Douglas XTB2D "Skypirate"
Joe Baugher: Encyclopedia of American Military Aircraft. Douglas XBT2D Dauntless II
Rene J. Francillon: McDonnell Douglas Aircraft Since 1920, Vol 1
Aerofiles.com.: Douglas


Let me end with some personal remarks. I am sorry that these aircraft in their original layout were not build. They exactly show the line between attractive WWII aircraft and there less attractive postwar successors. OK, I have easy speaking because my tax pennies are not the ones consumed for these projects, but sea power is not only to win, it is also to use. In hindsight, the US Navy was right in this decision, but could they really be sure these aircraft were never needed?

BTW, where did all the torpedo bombers go?

Hope you enjoyed!

Regards, RT



#2 Wuzak

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Posted 10 May 2008 - 06:47 AM

Contraprops look ungainly when they aren't fitted with spinners!

I guess the logical competitor for these two would be the Martin AM Mauler?

#3 Wuzak

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Posted 10 May 2008 - 06:50 AM

quote:Originally posted by Romantic Technofreak

BTW, where did all the torpedo bombers go?


Not really required in these days of cruise and anti-ship missiles.

#4 Red Admiral

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Posted 10 May 2008 - 05:52 PM

quote:BTW, where did all the torpedo bombers go?


I think it was more the fact that flying at low level straight towards the target festooned with effective AA guns would result in massive losses. A better weapon might have been a gyro stabilised glide bomb dropped from further away.

#5 Romantic Technofreak

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Posted 10 May 2008 - 10:19 PM

Honestly I have a knowledge gap here. To me, it seems that the era of the torpedo bomber also ends more or less with the end of WWII. In a time, when good ballistisc missiles and glide bombs that hit with certainity were still not available for a long time. And even today, it is better to hit a ship under the waterline for to sink it. But maybe this is just the problem. Sinking a ship as military success might be WWI-thinking, not post WWII-thinking.

Regards, RT


#6 Lightning

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Posted 10 May 2008 - 11:36 PM

Hi RT,

Thanks loads for all the great photos. Many of them I have never seen before.

You always keep things interesting.

Regards,
Lightning

#7 r16

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Posted 12 May 2008 - 02:10 PM

in post war years the Russians used Il-28 Beagles as torpedo-bombers with rocket powered units up to Khruschev , who was definitely pro missile and went on to scrap the capability .

#8 Romantic Technofreak

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Posted 08 December 2013 - 02:40 PM

Tried to use the new uploading option... doesn't work. I have no permission to view my own uploads. Going to use the traditional way.

Maybe you can see the upolads. I can't delete them.

 

Regards, RT

Attached Files



#9 Romantic Technofreak

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Posted 08 December 2013 - 03:14 PM

OK, let's see what we have here:

 

6261613737623339.jpg

 

 

3239343166653332.jpg

 

3035336138356635.jpg

 

3566393737653835.jpg
 

6238613031663635.jpg
 

3635643539373261.jpg

 

6161303765366563.jpg

 

I don't remember the sources for #1-2 and 5. #3 is from the US Militaria Forum Quiz. #4,6 7 and 8 are from flickr.com, exactly from theses accounts:

#4, 6: Tormentor4555

#7: San Diego Air and Space Museum

#8: Lord Kitchener.

 

Regards, RT



#10 Paolo Tagliaferri

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Posted 20 December 2013 - 08:17 PM

Very sleek plane!


Paolo Tagliaferri

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