Which aircraft would you cancel?

[GrauGeist]

Great shots, Joe and is a reminder that the airwar wasn't all about the pilots or their rides, but the guys behind the scenes keeping them in the air.

Perhaps not as glamorous, but just as important.

 

[Jugman]

Let me clarify. Here is one Fifi's cowlings -from Dave Miller's Photobucket page-.
http://i377.photobucket.com/albums/oo219/b2924crewchief/IMG_3444.jpg
As can be seen the cowl ring and cowling frame is a single structure. Late war aircraft had a "split" cowl ring allowed the cowling to be removed with out taking the propeller off first. The removable side panels did not offer full access to cylinder rows. The nacelle access panels to accessory compartment were rather small as well. Dave's Photobucket page has a lot of great photos of Fifi. Dave Miller's Library

 

[FLYBOYJ]

Let me clarify. Here is one Fifi's cowlings -from Dave Miller's Photobucket page-.
http://i377.photobucket.com/albums/oo219/b2924crewchief/IMG_3444.jpg
As can be seen the cowl ring and cowling frame is a single structure. Late war aircraft had a "split" cowl ring allowed the cowling to be removed with out taking the propeller off first. The removable side panels did not offer full access to cylinder rows. The nacelle access panels to accessory compartment were rather small as well. Dave's Photobucket page has a lot of great photos of Fifi. Dave Miller's Library

I see nothing there no worse or no better than about a half of dozen other QEC radials I've been around, and all this had little to do with the B-29 having a QEC. The one photo I showed had a guy with half his torso inside the side panel. QECs actually made maintenance easier as everything was basically ready to bolt on once one engine was removed. Granted, the one piece cowl was a bad idea. Your original statement about the B-29 QEC "this made any kind of maintenance task far more difficult than need be" is very far reaching and would be more dependent of the the "configuration" of the QEC rather than a QEC itself. You also have to consider what kind of maintenance you're talking about (preflight inspections, changing spark plugs, inspecting or adjusting rocker arms, timing mags, etc., etc., etc.....

 

[pinehilljoe]

Its hard not to decide without the use of hind sight. Thankfully the US had the resources to produce 10s of thousands of planes and still spend money on what would turn out to be dead end projects. In the heat of war who knew which design would be classic and which would be a dud.

The one "what if" I like to think of is if the USN had put more funding into the Corsair and had it in production to be in the Fleet in time for Midway. First flight in May 1940, put more money into development and what if the Corsair were deployed on Carriers in time for the Midway and the Early Soloman's Carrier Battles.

 

[Greyman]

Obviously more investigation is required!

In reference to our self-sealing oil tank discussion on page 15:

In reply to an enquiry dated 12 July 1943, a letter was sent to Air Ministry giving details of all known strikes on self-sealing oil tanks, together with remarks on the efficiency of the self-sealing covers. It was pointed out that operational experience gave little evidence to contradict the experimental results obtained at R.A.E. which showed that the self-sealing on an oil tank could rarely expected to be of value. There was considerable discussion with R.A.E. and M.A.P. on this matter, and when later it was felt that the saving in crude rubber, of which supply was critical, would be substantial, this section recommended the substitution of a crash proof felt covering in place of self-sealing cover. This was agreed and put into service.

- Operation Research in Bomber Command, Air Historical Branch, Air Ministry​

 

[stona]

This is an illustration of the almost mundane work done by the various ORS. They concluded that it was simply not worth fitting self sealing oil tanks. The Pilot's Notes obviously contain an erroneous description of the 'crash proof' covering as 'self sealing'.
It also explains the discussion in 1943 at which the idea of self sealing oil tanks was mooted before the 'crash proof' compromise was finally arrived at.
Cheers
Steve

 

[Greyman]

The May '44 Pilot's Notes might not necessarily be in error - as we have no concrete data on how quickly the 'self-sealing' oil tanks were changed over to 'crash-proof'.

Even if the change at the factories was immediate it would take time for the majority of Lancasters, Halifaxes and Stirlings to have the new tank coverings.

 

[stona]

I don't believe that they were ever self sealing. The discussion about the possibility wasn't until 1943, then Bomber Command's ORS and other bodies would have investigated before making recommendations, this was absolutely standard practice. That recommendation was that the use of materials to make the tanks self sealing, when there was little evidence to support the contention that this was even necessary, could not be justified. I don't have that report, I'd be surprised if it didn't mention the weight too, as just about every other one I've seen which might lead to the addition of equipment to a bomber does!
The tanks were to be made 'crash proof' rather than self sealing, though how exactly felt achieved this I don't know.

In flight fires, and the means of preventing or extinguishing them, exercised the minds of the scientists of Bomber Command's ORS throughout the war. In every case when an emergency/safety system was proposed a compromise was arrived at. These usually traded off weight, cost and other penalties, like delays in production as yet another modification was introduced, against the number of aircraft (and crew) which might be saved. Some hard choices were made. The Lancaster's forward escape hatch never did increase in size, despite pressure from the top (including Harris) that it should.

Returning to the original premise of this thread,in early 1943 a comparison of losses between the Lancaster and Halifax III was undertaken. This showed that in February and March of that year the Halifax suffered roughly 40% and 30% higher losses than the Lancaster. Given the lighter bomb lift of the Halifax the ORS stated that the "relative usefulness of these to aircraft may be given as 1:2.6"
It was this that led to Harris' 'Top Secret and Personal' letter to Freeman (copies to the Secretary of State and Chief of Air Staff) in which he made the case to cancel the Halifax and manufacture more Lancasters. It wasn't a letter based on bias or opinion but hard statistics.
There are well known reasons why the Air Ministry persevered with the Halifax, understandable at the time, but it was a mistake. Fewer but more useful bombers, in the Lancaster, would have been a better decision and the Halifax should have gone. Unfortunately the men at the Ministry and in Parliament tended to look at the total numbers and feared a reduction in overall numbers of heavy bombers which would have been inevitable as production switched from Halifax to Lancaster.

Cheers

Steve

 

[Greyman]

I don't believe that they were ever self sealing.

Every indication is that they were from the beginning. The ORS investigation and meeting you mentioned were about self-sealing tanks in service at the time.

 

[stona]

Could be, at least reading your post above. I don't have access to any of my books at the moment.
Why were they still described as 'self sealing' in the later pilot's notes? Maybe they never got properly edited. Anyone whose looked at similar documents for the successive marks of any aircraft will see how that can happen
Cheers
Steve

 

[Greyman]

Could be, at least reading your post above. I don't have access to any of my books at the moment.
Why were they still described as 'self sealing' in the later pilot's notes? Maybe they never got properly edited. Anyone whose looked at similar documents for the successive marks of any aircraft will see how that can happen
Cheers
Steve

Entirely possible, or the modification ended up not being carried out, or not at an appreciable scale. I think Occam's Razor would point to the notes not getting the small edit.

Found another document (5 Dec '41) dealing with Lancaster II armour proposals and it specifies oil tanks have Semape self-sealing protection.

 

[GrauGeist]

On page 152 of "The Science of Bombing: Operational Research in RAF Bomber Command" by Randall Thomas Wakelam, it covers the meeting by Dickens and Lovell with the staff of the Structural and Engineering Department of the RAE. During this meeting, they reviewed the issue of self-sealing oil and fuel tanks for the Lancaster, and the decision was made to test 100 Lancasters with the Bransom Tank system, which would, by the way, add 1,000 pounds to the aircraft.
On the subject of the Oil Tank, it was decided to apply armor plate as protection instead of self-sealing covers, because "the statistics that support the need was insignificant."

 

[stona]

I've never been able to find out what a 'Bransom' tank actually was. It was bloody heavy!
Subsequently it was decided that the inner wing fuel tanks were too big and should be sub divided, but I'm not sure that happened either. The large tanks meant that loss of fuel from one would reduce the aircraft's endurance to the point where it was unlikely to return home.

I've seen the report which recommends armour for the oil tanks but then there is the references to self sealing tanks and the mention of the self sealing material.
It is often difficult to establish which recommendations were in fact implemented from the minutes of the meetings or the ORS reports.

Cheers

Steve

 

[Greyman]

My guess is the Bransom tank system is the system that added the fire extinguishing and inert gas equipment to each petrol tank. Though from what I can add up this would only come to about 600 lb.

 

[stona]

The inert gas for the fuel tanks and Methyl Bromide extinguishers for the engines rather than tank bays weighed in at 500lb according to the minutes of a September 1943 meeting with the CEngO and other big wigs. It is reasonable to suppose that a similar system with extinguishers in the tank bays would be of similar weight, so 600lb does not seem unreasonable.
I think that the Bransom tank system may have included some armour.
Cheers
Steve

 

[Greyman]

Numbers I come across (all estimates near as I can tell):
300 lb - nitrogen equipment for tanks
300 lb - methyl bromide equipment for tank bays
200 lb - methyl bromide equipment for engines

 

[buffnut453]

Canceling the F4F and building F2As would have been a big mistake. The F2A gets it's good reputation from the early light versions.
Granted navy requirements porked it up a bit more than was necessary but the F2A was a small plane without a lot of growth in it. It would have hit a wall pretty soon in development no matter what.
The F2A-3 was over 1000lbs heavier empty than the XF2A-1 and export 239. The wing gained 172lbs while the airframe as a whole gained 280lbs. This is, in part, due to the powerplant gaining 547lbs. Early planes used engines with direct drive (prop turned same speed as the crankshaft) and single speed superchargers. Later engines (the 1100-1200hp ones) had reduction gears and two speed blowers, they also got propellers about 15in bigger in diameter. Fixed equipment also went up.

An R-1830 with two speed supercharger (not two stage) was about 80-120lbs heavier than the R-1820 used in the F2A-3.

The F2A actually had a rather small wing. While it was 208 sq/ft gross it was only 178 sq. ft. net due to the fat fuselage. This compares to the P-39 with a 213 sq/ft wing gross and 197 sq/ft net. Wing area goes from 97.7% of the P-39 to an actual 90% of the P-39 wing. You can only add so much "stuff" before the wing loading climbs to unacceptable levels.

Given the .50cal MG dislike of being synchronized you have a firepower problem (although not a big one) with two guns in the cowl and a gun in each wing compared to 4 guns in the wings. you are down 6-8 bullets per second total from the wing mounted guns. Sort of like having 3 1/2 guns instead of 4.
Going to six guns is never going to be an option with the F2A.
Maintenance on the F2A could be a real pain in the A**. It used a one piece wing.

Replacing major wing parts was not easy. Note that the landing gear was in wing.

I agree with your comments about growth potential in the F2A. A significant proportion of the weight increase in the later marks was due to installation of armour plating and self-sealing fuel tanks. Entirely agree that the F2A-3 was very much overweight but the -2 wasn't so bad, and in operation steps could be taken to reduce the weight depending on mission and role (as the Aussies did with their aircraft in Singapore). The F4F was clearly a better aircraft...but it had some opportunity to learn from the mistakes of it's slightly older Brewster competitor.

Regarding the one-piece wing, presumably that failing would also apply to other types of a similar construction methodology...like the P-40? Yes, I know it's not a Navy aircraft but the problems of battle damage repair in a combat zone aren't too terribly different.

 

[stona]

Numbers I come across (all estimates near as I can tell):
300 lb - nitrogen equipment for tanks
300 lb - methyl bromide equipment for tank bays
200 lb - methyl bromide equipment for engines

That adds up perfectly with the numbers I have.

Cheers

Steve

 

[Shortround6]

Regarding the one-piece wing, presumably that failing would also apply to other types of a similar construction methodology...like the P-40? Yes, I know it's not a Navy aircraft but the problems of battle damage repair in a combat zone aren't too terribly different.

Part of the repair problem with the F2A was that the original fuel tanks were built integral with the wing. Front and rear spars were the front and rear walls of the fuel tanks. On the P-40 the fuel tanks were separate components that could be dropped out of the wing structure. Fuel tanks fit in empty spaces between wheel wells. Fuel tank repair was easier. Not really easy as panels had to taken off to reach tanks but easier than F2A.

P-40 wing, while often shipped in one piece, could be split in the middle. P-40 sat on top of the wing or at worst, wing was recessed into the bottom. F2A was a mid wing plane with a one piece wing.

You need a couple of extra feet of height to get the fuselage off the wing. Not impossible, just a bigger pain in the ass.