History, Politics And Current Affairs

Opinions expressed here are personal views of contributors and do not necessarily represent the companies, organizations or governments they work for. Nor do they necessarily represent those of the Board Administration.
It is currently Tue Jan 16, 2018 10:03 am

All times are UTC - 5 hours




Post new topic Reply to topic  [ 61 posts ]  Go to page Previous  1, 2, 3, 4  Next
Author Message
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 4:04 pm 
Offline
User avatar

Joined: Thu Oct 30, 2008 2:37 pm
Posts: 7553
Location: BM-9, BB-30
That does indeed sound very Russian...

The interesting bit about KINGFISHER to me were actually the proposals that didn't make it. PUFFIN, which was supposed to carry a "plunge bomb" (which the sources are oddly silent on beyond it basically seeming to be a non-bouncing version of the principle behind UPKEEP), GREBE, which is perhaps the most interesting technically as it seems to have been technically and operationally identical to Malafon and Ikara, but was let down by the sonar performance of the time; and the most outlandish, DIVER, which was supposed to use an all-new torpedo with rocket propulsion(!) that was supposed to both propel the missile in flight and the torpedo itself underwater following release(!!). "Surprisingly", that couldn't be made to work.

GREBE, at least, sounds like something that could easily have made the cut for TBO.

Image

_________________
RLBH wrote:
I'm sorry, but I prefer to carpet-shark my enemies. Much more mayhem, though it must be admitted that the laser-guided shark is cheaper.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 4:15 pm 
Offline
User avatar

Joined: Fri Oct 03, 2008 10:49 pm
Posts: 10895
Grebe does sound rather plausible doesn't it. I'll do some more digging - thank you for the tip-off

_________________
Nations do not survive by setting examples for others.
Nations survive by making examples of others


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 4:59 pm 
Offline
User avatar

Joined: Mon Feb 16, 2009 5:32 pm
Posts: 6490
Location: Currently 3rd Rock from the sun
Why did we toss out BAT and/or PELICAN for BULLPUP?

_________________
Faugh a Ballagh


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 5:47 pm 
Offline
User avatar

Joined: Thu Oct 30, 2008 2:37 pm
Posts: 7553
Location: BM-9, BB-30
Francis Urquhart wrote:
Grebe does sound rather plausible doesn't it. I'll do some more digging - thank you for the tip-off

Not a problem, sir! These obscure little projects are my jam.

jemhouston wrote:
Why did we toss out BAT and/or PELICAN for BULLPUP?

Well, PELICAN was cancelled by Ernie King in favor of BAT (even though at the time of cancellation Pelican had just had a successful test, with 50% (2/4) of missiles launched hitting the target hulk JAMES LONGSTREET, which for the time was outstanding performance); presumably the issues with semi-active vs. active guidance were recognized (would that we wouldn't have forgotten them so quickly). I'd assume the main reason BAT didn't retain favor after the end of WW2 was its sheer size - while the F4U/SB2C/TBF could carry it, I can't possibly see how toting a 11-foot-long, 10-foot-wingspan bomb along would produce performance described as anything other than "leisurely", and the aircraft that could carry two BATs while still being able to retain more maneuverability than the Brooklyn Bridge were the PB4Y and P2V, both of which had better things to do.

Image

With the tech of the time, an active radar seeker required something the size of BAT or GORGON, while a weapon capable of being carried without significant penalty by a fighter-bomber, like BULLPUP, had to have a rather...simpler guidance system, such as, say, MCLOS.

(Then of course there's the crazy ideas like OMAR, where a 5" rocket body was fitted with kit to provide guidance by optical beam-riding. If you're thinking that sounds like "shine a Leigh Light on the target and the missile flies down the spotlight beam", you're exactly right. :shock: )

_________________
RLBH wrote:
I'm sorry, but I prefer to carpet-shark my enemies. Much more mayhem, though it must be admitted that the laser-guided shark is cheaper.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 5:56 pm 
Offline
Site Admin
User avatar

Joined: Sat Oct 04, 2008 8:28 am
Posts: 5370
Location: CL-4, BB-14
I know nothing about OMAR, but your description of it (particularly the part about the Leigh Light) makes it seem like a useful weapon against surfaced submarines.

_________________
"If it's not the end of the world, I'm not coming!" - Kelsie at the SAC Museum

Inner Columnist


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 7:05 pm 
Offline
User avatar

Joined: Sat Oct 04, 2008 9:24 pm
Posts: 1875
Regarding my earlier mention of the New Developments Division (NDD); I have been looking at their stuff in the archives; and I found a letter from the OSS to the head of the NDD at the time, General Borden; regarding Nazi submarine launched V-1s, will upload it into this post later.

I also found lots of stuff regarding swimming tanks (both DD and other types) including a report of what happened to the DD tanks on D Day in the Decimal Files of the NDD.

Basically, if it was a "secret weapon" and it wasn't the atomic bomb, NDD was involved somehow from 1943 onwards...but they are missing from virtually every history of WW2.

_________________
Image


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 7:17 pm 
Offline
User avatar

Joined: Thu Oct 30, 2008 2:37 pm
Posts: 7553
Location: BM-9, BB-30
Theodore wrote:
I know nothing about OMAR, but your description of it (particularly the part about the Leigh Light) makes it seem like a useful weapon against surfaced submarines.

ASM-N-6 Omar.
It wasn't literally a Leigh Light (although I imagine one would work): an "intense beam of light" would be projected on the target, and the light sensors (...you know, that does explain why Kodak was prime contractor, come to think of it) would track the beam.

Apparently aside from the same old "have to keep flying at the target" problems, the issue of the spotlight beam diffusing with distance (as spotlights beams inherently do) was the main issue.

_________________
RLBH wrote:
I'm sorry, but I prefer to carpet-shark my enemies. Much more mayhem, though it must be admitted that the laser-guided shark is cheaper.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 9:34 pm 
Offline
User avatar

Joined: Fri Oct 03, 2008 10:49 pm
Posts: 10895
The Bushranger wrote:
Apparently aside from the same old "have to keep flying at the target" problems, the issue of the spotlight beam diffusing with distance (as spotlights beams inherently do) was the main issue.

It's a systemic problem with all beam riders. They get less accurate as the missile approaches the target which is what we really don't want.

_________________
Nations do not survive by setting examples for others.
Nations survive by making examples of others


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 11:00 pm 
Offline
User avatar

Joined: Sat Oct 04, 2008 9:24 pm
Posts: 1875
Regards Bushmaster's points of :

Quote:
if there was a pressing need for a Better TBF, you could accellerate that". There wasn't. So they didn't.
...

The problem with this reasoning is that the TBY Sea Wolf was not a successor, even by a half-generation, to the TBF/TBM Avenger. It was the Avenger's competitor, designed in 1939 and first flown two weeks after Pearl Harbor. A combination of being star-crossed and Vought being asked for twice the Corsairs they could build delivered yesterday, followed by the issues with Allentown (Brewster again!) and continued star-crossing issues, are why it "looks like" a 1944-1945 quasi-replacement.

Once you load on all the same equipment that was dragging down the Avenger - which they would have - how much faster would the Sea Wolf had been?

And engine commonality is a bug, not a feature, if Pratt & Whitney is already running at 110% trying to supply R-2800s for the F4U, F6F, B-26, A-26, P-47, and P-61 already. Remember that the main reason the A-38 died in @ was because the B-29 was slurping up the entire production supply of R-3350s; how much capacity did Pratt have for yet another aircraft using Double Wasps?


I'm answering all the above over several posts, etc because this is a complex issue with many interlocking parts.

Both the USN's VSB and VTB programs were a hot mess as opposed to the success of their VF programs.

I have the Branch Histories of the major BuAer Desks (VF, VSB, VT, etc) and so here we go, with the VSB desk going first.

********************************

The Scout/Dive/Attack Bomber Mess

To replace the SBD Dauntless, BuAer design competition letter Aer-PR-BA VSB dated 3 February 1941 was issued. Five companies submitted proposals; Brewster, Douglas, Vought, NAF, and Curtiss. Two airplane proposals were accepted for development, the Douglas SB2D-1 and the Curtiss SB3C-1.

SB3C

The Mock-up Board inspection of the SB3C-1 was conducted on 8 to 11 December 1941; and performance would have been:

R-3350-8 Engine
365 gallons internal fuel
2 x .50 Wing Guns (400 rounds)
2 x .50 Turreted Guns (800 rounds)
313 MPH @ Sea Level
349 MPH @ 16,000 ft
450 ft takeoff distance at a gross weight of 14,990~ lbs carrying a 1,000 pound bomb.

I have more detailed stuff on range etc, but not digging it out at the moment.

Development of the SB3C-1 continued until a conference at BuAer on 7 December 1942. It was decided that since the SB2C Helldiver appeared to be satisfactory, and to ease the engineering load on Curtiss, Columbus Ohio, in particular to expedite the SC Seahawk and BTC designs, it was recommended to cancel the SB3C contract, particularly since the SB2D now had greater performance than the SB3C.

SB2D

The mock-up of the SB2D-1 airplane was held at the contractor's plant from 18 August to 21 August 1941, receiving favorable reviews.

R-3350-14 Engine
Bomb Bay sized to carry 2 x 1,600 lb bombs internally.
2 or 4 x .50 Wing Guns (800 rpg)
1 x .50 in Upper Turret (800 rpg)
1 x .50 in Lower Turret (800 rpg)
Gross Weight from 14,000 to 16,000 lbs.

The SB2D had a number of new features:

* Remotely operated guns (Similar to that adopted by the A-26)
* Wing Fence Type Dive Brakes
* Laminar Flow Wing (only experience at this time was with the early Mustang prototypes)
* 16:9 gear ratio on the engine
* Tricycle gear. No experience was available in catapulting such a design.
* Landing Flaps. Double slotted and no flight data on such a design was available.

On 9 April 1942, a contract was issued for 358 SB2D-1, which was later replaced with a new contract on 31 August 1943, calling for 623 SB2D-1 aircraft to be delivered on the following schedule:

1 in November, 1943
1 in December 1943
2 in January, 1944
2 in February, 1944
3 in March, 1944
3 in April , 1944
7 in May, 1944
14 in June, 1944
32 in July, 1944
54 in August, 1944
71 in September, 1944
89 in October, 1944
106 in November, 1944
117 in December, 1944
118 in January, 1945
2 in February, 1945

In May 1942, the fixed armament was changed to 2 x 20mm M2 with 200 rds/cannon.

Development of the SB2D was slower than what BuAer was expecting, and BuAer complained that Douglas was devoting too much effort at the plant to the Army's A-26 program and not enough to the SB2D.

In the end though, what killed it was weight.

In March 1942, it was 275 pounds overweight. Somewhat manageable. But by April 1943, it was up 1,340 pounds overweight; leading to actual gross weights of 16,500 to 18,500 pounds instead of the 14,000 to 16,000 lbs the spec called for.

This was crucially important as carriers were deck weight limited.

On 7 September 1943, Douglas was informed via telephone conversation that the SB2D-1 was to be converted to a single seater aircraft to bring it's gross weight and takeoff performance in line with carrier requirements.

A mockup for the revised design was held in September 1943; and the changes were to be:

* Elimination of gunner's enclosure, seat, turrets, sighting station, armor plate, oxygen, and other equipment special to the rear seat.

* Elimination of landing light, two man life raft, provisions for propeller and windshield spray anti-icing, and other items of equipment.

* Fairing of the gunner's cockpit, and extension of the fin forward.

* Simplification of radio installation.

* A second fuel tank of 120 gallons capacity was added aft of the existing fuselage tank in the place of the former gunner's position. This brought the center of gravity position back to where it belonged and increased the internal capacity to 460-470 gallons of fuel.

The single seater SB2D-1 was then redesignated the BTD; with the first prototype, BuNo. 04959, making its first flight on 15 December 1943.

In May 1944, the schedule called for four BTD-1's to be delivered for Navy Trials by early July 1944 and deliveries for operational use in the latter part of July 1944; following a weight reduction program to trim 1,000~ lbs from the plane via the following major items, plus other minor items.

* Elimination of the bomb-bay and provision for the external mounting of bombs and torpedoes. (-300 lbs)

* Replacement of the two fuselage tanks by one single tank, saving weight in tank material. These changes were to be effective at different points in the BTD-1 production line.

Unfortunately for the program, on 10 May 1944, BTD-1, BuNo. 04963 arrived at Patuxent River for flight testing, which revealed:

(1) Longitudinal stability unsatisfactory in carrier approach condition.
(2) Lateral stability neutral to slightly negative in carrier approach condition.
(3) Insufficient rudder control in same condition as (2) above.
(4) Elevator forces too large in a pull-out.
(5) Take-off tests showed a distance of 590 ft. in 25 kts. wind, at a gross weight of 18,000 lbs, using 2300 HP and the Curtiss four bladed 13'2" propeller.

On 5 June 1944, in conference, BuAer concluded that the BTD-1 because of its deficiencies was not a sufficient advancement beyond the SB2C to be a replacement. Production plans for the BTD were then killed.

Changing Specifications and Needs

The USN's desires on what it wanted were changing even before the SB2D/BTD died officially.

In a converence held from 21-22 January 1942, BuAer discussed what they wanted in torpedo and scout bombers.

It was the opinion that the scout-mission should be transferred to the VTB type of airplane, making a conception of the single-seat dive bomber possible. The advent of radar had placed such a burden upon the radar operator that it was believed he could not be expected to serve as a look-out and rear gunner. This indicated the three-seater for use as a scout with radar search equipment. It was realized that this would make necessary a revision of the numbers of each type to be carried in the carriers, but only three types are needed. The proposed types would be VF, VBT, and VTSB.

...

It was estimated that by removing the second man, protective armament, and scout radio, from the present VSB type, a weight reduction of 1500 lbs. would be possible. This difference could be used in two ways: (1) The airplane could be reduced in size with a resultant gain in speed, at no sacrifice in other performance items; or (2) the weight difference could be used to provide more range, heavier pilot armor, and more fixed armament in an airplane of about the same size. It was considered very probable that a very excellent compromise could be effected with a reduction in size corresponding to about an 800 pound reduction in weight of an XSB2D-1, for example. A maximum speed of 390 mph was desired.

A recommendation was made that a single-seat type bomber torpedo airplane design be initiated immediately. It was further recommended that the Curtiss Wright Corp., Airplane Division, Columbus Plant, be requested to conduct a study of this design and to submit an informal proposal for the construction of two experimental airplanes.


Specifications were sent to Curtiss Wright on 9 February 1942 asking for:

Primary Mission:
Dive bombing attack.

Secondary Missions:
Torpedo Attack
Smoke screen laying.

Crew:
One.

Power Plant:
R-3350-Single stage, two speed.

Military Load:
(a) One 500 lb. bomb, normal, or,
(b) Two 1600 lb. -AP bombs or,
(c) Two 1000 lb. bombs or,
(d) Four 500 lb. bomb (two external) or,
(e) One MK 13-1 or -2 torpedo (external).
(f) Four 20mm fixed cannons firing forward, with 110 rounds per gun (normal) (with provisions for 200 rounds per gun).

Fuel and Oil:
Protected fuel for range of 1000 miles with one 1000 lb. bomb.

Additional Fuel:
Sufficient fuel in droppable tanks to provide an additional 500 mile range with 1-1000 lb. bomb. Range with torpedo to be that which results from the above total fuel load. unprotected tanks must be droppable when torpedo is carried.

Take-off:
Not greater than 250 feet in 25 kt. wind with one-1000 lb. bomb and 1000 miles, of fuel. Take-off under maximum overload with torpedo in 25 kt. wind - 350 feet.

Curtiss' proposal came out on 15 June 1942. Changes were deemed necessary and it was resubmitted on 13 July 1942.

Curtiss in effect proposed two VTSBs, one with the R-3350 and one with the R-4360.

BuAer considered that it was in everyone's best interest to pursue both designs simultaneously, as a R-3350 powered airplane could be available earlier in production; and it could eventually be changed over to the R-4360 design when that engine became production ready.

On 26 June 1942, contracts were issued for the BTC-1 (R-3350) and BTC-2 (R-4360); with Mockups of both planes being held on 16 December 1942.

Unfortunately, due to the priority of delivering a workable SB2C to the fleet, plus the priority for the SC Seahawk, both BTC designs fell further and further behind. Ultimately, Curtiss proposed cancelling the BTC-1 to concentrate on the BTC-2. This was accepted due to the overload of Curtiss' Engineering department at the time along with R-3350 teething troubles.

Late 1943

It's now late 1943, and the two contenders for the SB2C replacement are the BTD from Douglas and the BTC-2 from Curtiss.

The BTD incorporated many experimental features, while the BTC-2 was months and months behind due to the aforementioned troubles at Curtiss with production scheduling.

So when the Glenn L Martin Company of Maryland said they had excess design engineering capacity open, along with the forthcoming end of B-26 Marauder production clearing the production line, they were selected by BuAer to backstop the BTC-2 by designing a plane with the same engine, the R-4360 and the same basic design concept.

From November 1943 to January 1944, multiple designs were submitted by Martin and BuAer selected the Martin Model 210 for further development and the contract for the prototype BTM was signed on 7 January 1944.

The Mockup of the XBTM-1 was held 7-9 February 1944 and gave a good impression; the design was as conventional and simple as possible to obtain flight articles at the earliest possible date and to reduce maintenance man hours.

The first XBTM flew a little over a month behind schedule on 26 August 1944. On it's first flight test at 7000 feet, despite the engine throttled back to 67%, it stayed even with the B-26 chase aircraft which had it's throttles wide open.

On 15 January 1945, Martin received a letter of intent for 750 BTM aircraft.

Meanwhile back in the fall of 1943, at the same time the massive heavyweight Martin was being conceptually developed, it's polar opposite was also being conceptualized.

BuAer felt that a lightweight plane should be built to counter the trend for ever bigger dive bombers (and also to provide a small attack plane for CVEs). Following informal solicting, the Fleetwings Division of Kaiser Cargo, Inc submitted designs during December and January 1944; and a letter of intent was given for the BK on 23 February 1944.

The mockup was held 3-5 April 1944 and gave excellent impressions. As was the case with the Martin BTM, the design was kept as simple and conventional as possible to accelerate possible service entry.

The program was given extreme high priority by the USN, and instead of the usual two prototypes, 22 were ordered so that all the necessary flight tests could be run concurrently, instead of waiting for the single prototype to complete one phase and move to the other. Kaiser Fleetwings was also impressed constantly of the need for a modern combat single-seat dive-bomber, and was given all help possible to meet the shop completion dates as originally scheduled.

Additionally, to expedite tests, and avoid towing of the planes from the Kaiser Fleetwings plant to the nearest airfield at Trenton NJ, BuAer approved the construction of an airfield at the Kaiser Fleetwings plant.

On 30 November 1944, Fleetwings was told by the Chief of BuAer (RADM D.C. Ramsey) that the progress of the BK had created a bad impression in the bureau, despite the program having a sound design with an underweight status of 200~ pounds that was being maintained by the contractor during development.

By October 1944, it was obvious that the first BK wouldn't be shop completed by the contracturally specified November 1944, despite Kaiser working a 24 hour day; due to the following factors:

*The contractor's very cautious design of the various airplane components for weight control purposes, with resultant slowness in engineering release to the shop.

*Lack of experience with Navy specification, procedure, etc.

*Lack of organization which resulted in poor production planning and follow-up on sub-contracts, clausing shortages of subcontracted machined parts.

*The fact that the plant was under divided inspection, the Army Air Forces having primary cognizance, and the excessive number of projects that the contractor had accepted without apparent consideration of the small force he had to work with. These projects included the TBM-1 wing panels, F4U-1 horizontal stabilizers, B-17 fins, wings for the Hughes F-11 photographic airplane, a helicopter, and the XBK-1 airplane.

*The experimental shop within which the XBK-1 was being built was too small for efficient operation.

Despite all this, BuAer continued to cautiously support it, due to Kaiser transferring his best labor recruiters from his West Coast operations to the Bristol area to get more and better work, and because NACA wind tunnel tests on a powered model of the XBK-1 were showing exceptional aerodynamic characteristics in all flight conditions.

In December 1944, to improve the attack versatility of the BK, the contractor was requested to make the changes to add carriage of a Mk 13 torpedo on the centerline. Following the design changes, on 9 February 1945 CNO redesignated the BK to the BTK.

Under constant pressure from the VSB Design Branch, the contractor finally shop completed the first XBTK-1 airplane, BuNo. 44313, on 15 March 1945, and turned it over to the Bureau of Aeronautics Resident Representative for inspection on 24 March. It made its first flight on 12 April, 1945, six months after the scheduled flight date. Flight testing showed that it had exceptional dive bombing characteristics; possibly the best ever tested to that date by BuAer.

Because of the six month delay however, the BTK had lost it's chance at production -- on 1 November 1945, the second airplane was still in the final assembly stage, with the third, fourth and fifth planes scheduled for shop completion in 30 December 1945; 13 January 1946; and 27 January 1946, respectively.

1944 - Enter the Dauntless II

In June 1944 following the cancellation of the BTD program, Douglas was instructed to perform a complete redesign of the BTD-1 to see if anything could be salvaged.

Douglas submitted a proposal in July 1944 and the design was selected and designated BT2D.

BuAer at this time was getting desperate for a SB2C replacement sometime in the near future, and ordered fifteen XBT2Ds for concurrent flight test on the old BTD-1 contract -- C-NOa(s)-743.

At this point, the USN now had three expedited dive bomber programs running; the B(T)K, BTM and the BT2D in a desperate effort to get a new plane "in time for this war, not the next" to paraphrase Hap Arnold's words on the A-26.

Douglas, wanting to erase the unfavorable impression the SB2D/BTD program had left with BuAer, pulled no stops in the BT2D program, constructing a complete mockup in 45~ days; with the inspection being held 14-17 August 1944.

This was the first mockup of a VSB/VTSB done with full participation by the Maintenance Divison; to help design features into the plane(s) which would help handling/maintenance aboard carriers.

As with the previous B(T)K and BTM, the BT2D was a very conventionally designed aircraft with a minimum of experimental features to accelerate service entry.

At the mockup in order to expedite construction of the first two XBT2D-1s for flight test, it was decided these aircraft would use the main oleos of the F4U, with later aircraft having full strength landing gear.

Following approval of Detail Specification SD-379-T-1 in August 1944, nearly all of the engineering department of Douglas El Segundo was put onto the program, causing drawings to be released at a rapid rate; with all engineering for the prototype completed by 31 December 1944.

During detail engineering, Douglas; being very conscious that the BTD-1 had been some 3,000 pounds overweight, with it's wings failing during static test at around 15~ gees; decided to design the BT2D to the minimum strength level possible.

Basically, instead of designing a strong airframe to avoid failures in static test; the structure would be as close to the requirements as possible but on the negative side.

While this would cause many static test failures; the cost of redesigning to fix the static test failures in weight would be much less than a more rugged structure.

By 15 January 1945, progress on the XBT2D Dauntless II was:

Engineering: 100% Complete
Parts Fabrication: 71% Complete
Assembly: 46% Complete

The originally scheduled first flight of 1 May 1945 was moved up to 31 March 1945.

Due to Douglas' impressive performance (and to bridge the gap between the experimental and production planes if an order was placed), an additional ten XBT2D prototypes were ordered on 20 January 1945.

On 1 March 1945 Douglas was sent a request for preliminary planning and design of production tooling/line installation tooling for BT2D-1 aircraft.

The first plane, serial No. 09085, was shop completed the second week in March 1945, and made its initial flight on 18 March 1945, exactly seven months after the mock-up, and thirteen days ahead of the rescheduled first flight date. The airplane's actual weight was 1,800~ pounds under the weight guarantee.

By 29 March 1945, BuNo 09085 had twenty flights under it's belt with excellent results, and after three weeks of flight tests it was declared ready for preliminary USN evaluation. Arriving at Patuxtent River on 7 April 1945, the flight test of the XBT2D was given Priority "A" by BuAer, finishing on 17 May 1945.

On 12 April 1945, Douglas was informed by BuAer that they develop a rocket attack version of the XBT2D-1 that could hold internally and fire in a single burst fifty or more 5" spin-stabilized rockets. After study, Douglas responded that only about forty rockets could be carried in the wings.

On 16 April 1945, Douglas was informed by BuAer that the installation of a TG-100 turboprop was to be done in one XBT2D-1 aircraft. The mockup of this modification was inspected from 21 July to 17 August 1945.

On 18 April 1945, Douglas received a letter of intent for 548 production BT2D-1 aircraft; and proceeded to expedite this.

Meanwhile, the second XBT2D-1 (BuNo 09086) flew on 8 May 1945.

On 18 July 1945, Douglas was asked to study conversion of two aircraft to a new type, the Night Attack Version, designated BT2D-1N. The -1N would differ via:

* Provisions in the aft fuselage for two men (Radarman/Navigator and ECM Operator).

* Deletion of fuselage brakes

* Special electronics necessary to the mission of a night-attack airplane.

The mockup for the BT2D-1N was held 15-16 October 1945 and was found acceptable.

On 31 July 1945 status of the production BT2D was:

Engineering: 99.8% Done and released to Tool Planning.
Tool Planning: 55.7% Done and released to Tool Design & Fabrication.
Tool Count: 9,332 tools ordered to date, 6,760 tools in fabrication, and 2,572 tools completed, out of an estimated 19,500 tools required for production.

The third XBT2D (BuNo 09087) first flew on 17 August 1945. The third plane was the first to have full strength landing gear, allowing a full evaluation of the catapult/arrest cycle.

The third plane flew to NAMC Philadelphia for the official Service Acceptance Trials, arriving on 1 September 1945, with the preliminary report dated 25 September 1945.

1944 -- Curtiss Makes One Last Gasp with the BT2C

On 7 August 1944, Curtiss-Wright made an unsolicted proposal to BuAer for a SB2C Helldiver modified to have a R-3350 engine and a lengthened fuselage. On 14 September 1944 a conference was held to evaluate the proposal.

On 18 September, Curtiss was informed that the proposal was rejected due to:

*Slightly inferior performance to other single seat dive bomber designs (BT2D / BTK)

*Curtiss was appraised as not being able to set up a production line for this, due to their committments to the SB2C and SC aircraft. Changing over from the SB2C type to this proposed aircraft at the Columbus plant would have been significantly dangerous as the SB2C was the only dive bomber in production.

Curtiss then significantly revised their proposal and resubmitted it on 10 February 1945, and this time it met with BuAer's approval; being assigned to the Curtis Wright Columbus plant as a replacement for the SB2C; with production scheduled in W-13R (March 1945) to start with experimental prototypes in August 1945, working up to 150 planes in May 1946, the same month SB2C Helldiver production at Curtiss Columbus terminated in W-13R.

In order to obtain a working plane in the shortest possible time, Curtiss in their design of the BT2C used 50% of the parts of the SB2C-5, for approximately 68% of the weight being the same, allowing the use of large amounts of production tooling set up for the SB2C-5.

However, for some reason, by the time of W-14R (25 May 1945), the BT2C program was dead, reduced to just the prototypes.

***********************************************************************************

That's pretty much it. You can see how the USN was operating in "money as a weapon" mode by 1943-1944, as it tried desperately to get replacements for the Helldiver; to the point of running concurrent development programs, ordering a new plane when the first faltered.

Heavyweight Dive/Torpedo:
Curtiss BTC
Martin BTM

Lightweight Dive/Torpedo:
Kaiser BTK
Douglas BT2D

Additionally, you can see how the BT2D Program (aka AD Skyraider) is already operating at 200% full speed ahead. You can't really push it that much more.

Next up (tomorrow) the sad story of the torpedo bomber program.

_________________
Image


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Fri Jan 12, 2018 11:52 pm 
Offline
User avatar

Joined: Thu Oct 30, 2008 2:37 pm
Posts: 7553
Location: BM-9, BB-30
MKSheppard wrote:
That's pretty much it. You can see how the USN was operating in "money as a weapon" mode by 1943-1944, as it tried desperately to get replacements for the Helldiver; to the point of running concurrent development programs, ordering a new plane when the first faltered.

Heavyweight Dive/Torpedo:
Curtiss BTC
Martin BTM

Lightweight Dive/Torpedo:
Kaiser BTK
Douglas BT2D

Additionally, you can see how the BT2D Program (aka AD Skyraider) is already operating at 200% full speed ahead. You can't really push it that much more.

Next up (tomorrow) the sad story of the torpedo bomber program.


Hm, that's fair with the BT2D/AD, then. :D

Doesn't change the fact, though, that the TBU/TBY wasn't the plane they needed (or deserved) to replace Avengers with, then, since it should have been the plane that was introduced in May 1942 with a single squadron of Marines heading out into the Battle of Midway...

_________________
RLBH wrote:
I'm sorry, but I prefer to carpet-shark my enemies. Much more mayhem, though it must be admitted that the laser-guided shark is cheaper.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Sat Jan 13, 2018 12:31 pm 
Offline
User avatar

Joined: Sat Oct 04, 2008 9:24 pm
Posts: 1875
Shower thought:

The Navy's dive/level bomber program was the victim of the contractors they chose, Curtiss and Douglas.

Douglas was handling the following planes during WWII at various stages (arranged by type)

DC-3/C-47 Dakota
DC-4/C-54 Skymaster
C-74 Globemaster

A-20 Havoc/Boston
A-26 Invader

B-17 (as BVD Consortium)
XB-19
XB-42/XB-43 Mix/JetMaster

SBD Dauntless
SB2D / BTD
BT2D Dauntless II / AD Skyraider

TB2D Skypirate

Curtiss was handling a whole plate:

C-46 Commando
C-76 Caravan

SO3C Seamew
SC Seahawk

P-40 Warhawk/Tomahawk
XP-46
XP-53 / P-60
XP-62
XP-71
XF14C
XF15C

SB2C Helldiver
XSB3C

With three of them deemed high level priority (C-46, P-40, SB2C)

Some were mature designs, but even those needed continuing engineering support for the users and production line (C-47/C-46), while the experimental designs, even if they went nowhere, still consumed scarce engineering man-hours.

In the late 1930s there was a huge jump in technology development costs; which started to squeeze the smaller countries out. Witness how Italy and other minor tier nations were capable of designing decent somewhat competitive aircraft in the 1920s through 1930s, but with the 1940s, they slowly began to be squeezed out by the bigger nations; ultimately ending with the "big powers" being the only ones capable of designing fairly modern jet aircraft.

Case(s) in point:

1920s:
Ryan NYP "Spirit of St. Louis" cost only 850 engineering man hours (incl. performance/flight testing) and 3,000 man hours to construct.

1940s:
Mustang NA-73X Prototye: 78,000~ engineering man hours.
Mustang Further Development Engineering Manhours up to 1943: 156,000.
Total Man Hours up to maybe the P-51A: 234,000 manhours

Hurricane Mk I: 170,000 design man hours

Spitfire Mk I: 330,000 design man hours; 800,000 man hours for tooling; total man hours 1.13~ million
Total design/engineering Man Hours for all later Spitfire Marks after Mk I: 620,000.
---Spitfire Mk.21: 165,000 design man hours for this mark alone

Douglas DC-4/C-54: 500,000 engineering man hours + 100,000 man hours of lab test time.

The F-86 was said to consume 27 times the manhours that the Mustang had taken; so about 6.3~ million man-hours.

_________________
Image


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Sat Jan 13, 2018 2:00 pm 
Offline
User avatar

Joined: Thu Oct 16, 2008 4:47 pm
Posts: 3432
Location: Germany
Francis wrote:

Quote:
In fact, a good argument can be made that if Japanese warships had had the kind of intermediate-range AA firepower than American ships had, we'd have seen torpedo-bombing dying off a lot earlier.


I make the counter argument. What's the replacement? Guided bombs/missiles could do the trick or not. The FritzX did sink a BB but it required a medium bomber to launch. Not an option for carriers. Though the lighter BAT could be launched from single engine planes but how good cloud it have been against armoured ships? More abot that later. Glide bombing? Even less so IMO. You had to drop from a very specific speed and altitude but you didn't have to lead the target beause the bombs were moving so fast and they were dropped from a short distance. If decent medium AA enters the equation that should become even more dangerous than torpedo attacks. Speaking off. Late war Mk.13 could be dropped at impressive speeds and altitudes. WAG: We'd see an even better Mk.13. Combined with DB and fighter bomber attacks to supress the medium AA. And weapons like the BAT become more important if (!!!) their development can be accelerated and they can made to work against carriers and BB. Despite one example to the contrary bombs weren't that effective against CV, nor to mention BB. The latter require the use of torps or a FritzX if you have one.

_________________
trekchu wrote:
It was worse than he had expected. It was so incomprehensibly bad that he'd rather watch Pearl Harbor on a constant, never-ending loop than...


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Sat Jan 13, 2018 3:10 pm 
Offline
User avatar

Joined: Thu Oct 30, 2008 2:37 pm
Posts: 7553
Location: BM-9, BB-30
M.Becker wrote:
I make the counter argument. What's the replacement?

That was the entire point of Project KINGFISHER - stand-off torpedo delivery. The USAAF actually developed, fielded, and used in combat a similar device, the GT-1, even claiming a hit against a fleet carrier(!). Projects GLOMB and GARGOYLE would likely have also seen accelleration in that case.

_________________
RLBH wrote:
I'm sorry, but I prefer to carpet-shark my enemies. Much more mayhem, though it must be admitted that the laser-guided shark is cheaper.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Sun Jan 14, 2018 7:20 am 
Offline
User avatar

Joined: Sun Oct 05, 2008 11:42 pm
Posts: 257
Here's an after action report covering a few days (27Jun-1Jul44) of Brit 75mm Shermans taking on Tigers and Panthers successfully.
3 Tigers: 2 burned, 1 bailed
3 Panthers, 1 burned, 1 bailed, 1 disengaged
2 MkIVs: 1 bailed, 1 destroyed
https://i.imgur.com/YoFenge.jpg

Also, regarding Sherman ammo fires:
1) the MkIV had a greater chance of burning after taking 2 hits then the early Shermans (Brit ORS reports)
2) the Germans never put much effort into protecting the ammo, always having ammo in the sponson storage, while the Sherman did have it moved to protected locations in later models.
3) there's a PDF on the 6thAD over on CARL Digital Library that mentions how they cut out the honeycomb cells in the ammo storage to increase total main gun round count to 130 rounds. (Super Sixth in Exploitation, Operation Cobra):

Quote:
Personnel of the division ordnance battalion visiting other ordnance organizations which had been in combat in support of armor found that further modifications could be made to increase the orderly stowage of ammunition in tanks. The maintenance personnel of the ordnance proceeded to modify as many tanks as they could by cutting out the honeycombed ammunition racks in the tanks. This increased the ammunition capacity to 130 rounds of 75-mm shells, and 10,000 rounds of caliber .30 ammunition for machine guns.


direct link to pdf-12mb


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Mon Jan 15, 2018 2:55 pm 
Offline
User avatar

Joined: Fri Oct 03, 2008 10:49 pm
Posts: 10895
MKSheppard wrote:
FU screwed up and edited my post out of oblivion. I recovered it through my phone's offline cache.


Not knowingly I didn't. I may have hit Edit rather than quote but I don't think so. Anyway, if I did screw up your post, I'm really sorry. Such was not my intent and I apologize for any such result.

_________________
Nations do not survive by setting examples for others.
Nations survive by making examples of others


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Mon Jan 15, 2018 4:09 pm 
Offline
Site Admin
User avatar

Joined: Sat Oct 04, 2008 9:55 am
Posts: 17813
Location: Chicagoland
Francis Urquhart wrote:
MKSheppard wrote:
FU screwed up and edited my post out of oblivion. I recovered it through my phone's offline cache.


Not knowingly I didn't. I may have hit Edit rather than quote but I don't think so. Anyway, if I did screw up your post, I'm really sorry. Such was not my intent and I apologize for any such result.


No, I think I did, or is that a different post? I apologize.

_________________
- Dennis

Victory at all costs, victory in spite of all terror, victory however long and hard the road may be; for without victory there is no survival."
-Sir Winston Churchill


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Mon Jan 15, 2018 6:56 pm 
Offline
User avatar

Joined: Sat Oct 04, 2008 9:24 pm
Posts: 1875
from GUIDED MISSILES, JUNE 1944:

Attachment:
AAFM_19_GT-1.gif
AAFM_19_GT-1.gif [ 249.44 KiB | Viewed 56 times ]


The GT-1 is a glide torpedo using the GB-1 type of airframe, the controls of which can be preset to land the torpedo in a general area. The torpedo itself is also pre-set to follow a pattern of increasingly large circles or to zig-zag after it enters the water. A fraction of a second before it strikes the water the airframe is jettisoned by means of a paravane, which consists of a small can suspended about 20 feet below the missile. When the paravane strikes the water and drags, it detonates a small charge which releases the shackles holding the airframe to the torpedo. Although the present technique in the use of the glide torpedo is not sufficiently accurate to warrant its use against individual ships, it should prove an effective weapon in crowded, heavily-defended harbors.

_________________
Image


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Mon Jan 15, 2018 7:00 pm 
Offline
User avatar

Joined: Sat Oct 04, 2008 9:24 pm
Posts: 1875
GB-8

GB-8 is a 2000-pound low-angle radio-controlled glide bomb, controllable for both range and azimuth. This missile is similar to the GB-1 but in addition it has flares, a radio receiver, and solenoids for the application of control. Two sets of controls are used in the releasing airplane, the bombardier controlling for range while a crew member located in the waist gunner's position controls for azimuth. If the target is a linear one, a course parallel to it may be flown. For point targets a circular course must be flown so that variations in range may be observed. Against such targets the plane goes into a circular course subsequent to the bomb's release, and such, control is applied as will cause the bomb to eclipse the target at all times. This means that the pilot must make good a circular course, the radius of which is from 6 and 8 miles, with the target as its center. This can be roughly accomplished by sighting the target over a particular portion of the wing and maneuvering the aircraft to keep the resulting line of sight constant.

Attachment:
AAFM_19_GB-8.gif
AAFM_19_GB-8.gif [ 288.32 KiB | Viewed 55 times ]

_________________
Image


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Mon Jan 15, 2018 7:16 pm 
Online
User avatar

Joined: Sun Oct 05, 2008 9:40 pm
Posts: 5726
MKSheppard wrote:
GB-8

GB-8 is a 2000-pound low-angle radio-controlled glide bomb, controllable for both range and azimuth. This missile is similar to the GB-1 but in addition it has flares, a radio receiver, and solenoids for the application of control. Two sets of controls are used in the releasing airplane, the bombardier controlling for range while a crew member located in the waist gunner's position controls for azimuth. If the target is a linear one, a course parallel to it may be flown. For point targets a circular course must be flown so that variations in range may be observed. Against such targets the plane goes into a circular course subsequent to the bomb's release, and such, control is applied as will cause the bomb to eclipse the target at all times. This means that the pilot must make good a circular course, the radius of which is from 6 and 8 miles, with the target as its center. This can be roughly accomplished by sighting the target over a particular portion of the wing and maneuvering the aircraft to keep the resulting line of sight constant.

In other words, maneuver the dropping plane so that even HACS has a decent chance of shooting it down. Trying to do so over a US task force would be suicide.

_________________
(English doesn't) just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary.--James D. Nicoll


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: M26 Pershing:
PostPosted: Mon Jan 15, 2018 8:05 pm 
Offline
User avatar

Joined: Thu Oct 30, 2008 2:37 pm
Posts: 7553
Location: BM-9, BB-30
Which is probably why GB-8 never saw service.

IIRC the only of the GB series to see use was GB-1, which used a preset autopilot. It was used once, against Cologne in May 1944, with 42 of 113 GB-1s actually hiting minute-of-city accuracy; about half of the 113 suffered battery failure and spun in, the German flak gunners thought they were having a turkey shoot, and 8th Air Force went 'Just Say No' to glide bombs after that. I assume it was 9th AF that used most of the rest of the 1000+ GB-1s used during the war.

_________________
RLBH wrote:
I'm sorry, but I prefer to carpet-shark my enemies. Much more mayhem, though it must be admitted that the laser-guided shark is cheaper.


Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 61 posts ]  Go to page Previous  1, 2, 3, 4  Next

All times are UTC - 5 hours


Who is online

Users browsing this forum: The_Enemy and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group