Folding wings on British bombers

[Robert Porter]

Thats HUGE!

 

[pbehn]

As I remember from my childhood, most Airfix models of the Halifax were done with the wheels up, the model version just didnt hold the planes weight, pretty much like the real thing in a heavy landing.

 

[stona]

Thats HUGE!

And heavy! One of the reasons that the Stirling put on nearly 10,000 lbs between design and prototype...and then got heavier.
Cheers
Steve

 

[pbehn]

And heavy! One of the reasons that the Stirling put on nearly 10,000 lbs between design and prototype...and then got heavier.
Cheers
Steve

Did it get married?

 

[Shortround6]

Well, when you limit the tyre pressure to 38lbs/sq in you need BIG tyres to hold up a 50-60,000lb airplane.
Also note that complicated folding mechanism of the Stirling did get that big tyre into the middle of the Nacelle and not the rear end of the nacelle like a simple pivot would. Allowed for a more streamline undercarriage stowage? Less change in center of gravity as undercarriage raised and lowered?

 

[pbehn]

Less change in center of gravity as undercarriage raised and lowered?

The simple solution would be to add a few feet on the nose and tail so the effect wasnt so pronounced, the Stirling just wasnt long enough or heavy enough. I must admit I hadnt thought of the change to the CoG but that must be a consideration on a max loaded bomber on take off.

 

[XBe02Drvr]

The simple solution would be to add a few feet on the nose and tail so the effect wasnt so pronounced, the Stirling just wasnt long enough or heavy enough. I must admit I hadnt thought of the change to the CoG but that must be a consideration on a max loaded bomber on take off.

"Hey matey, help me heave for'rd on the bloody yoke when we stow the undercarriage! Christly basta'd tries to rear up like a bloody stallion!"
Once flew from Boston to Burlington with 400 pounds of CoMat in the aftmost baggage compartment that wasn't on the manifest or the weight and balance report. CG four inches out of limits aft. Rocky the flying squirrel! We didn't fly the plane so much as herd it. Up, down, right, left, pitch, yaw, it wanted to go anywhere but straight ahead. We often flew loaded at or near the aft limit, it was the nature of the beast, so we were used to that sort of behaviour, but not to that extent. We were a green crew with an FAA Inspector breathing down our necks and listening to our conversation, but if we'd had more experience and less pressure, we probably would have gone back and landed and sorted it all out. As it was, when we shut down in Burlington, two hefty baggage smashers hopped up into the baggage compartment to throw down the bags, the plane promptly sat down on her tail, and the inspector was launched from the airstair door to an unceremonious landing on the tarmac. Heads rolled in the Boston station, our major code share partner got fined, and the captain and I got a lecture from the inspector and some remedial training.
PS: About a month later a sister ship to ours up in Alaska, loaded identically to ours (CG 4" out of limits aft) augered in when the gear retracted, with the loss of 19 passengers, 2 crew, 36 bags, AND 400 POUNDS OF UNDOCUMENTED MOOSE MEAT! There but for the grace ...........!

 

[stona]

Returning to the Stirling, I have just noticed a strange coincidence. The Stirling fuselage is very close in overall length to that of the Sunderland (less than 2' difference over an overall 87' 3").
Is this coincidence, or did Shorts adapt the upper part of the Sunderland fuselage to become the Stirling? It would have been an expedient way to reduce overall development time and cost.
I don't know.

I keep seeing, all over the internet and in print, the opinion expressed that the reduction in wingspan from 112' to 100' was the cause of the Stirling's performance problem. It wasn't but that's another discussion
If the wingspan limit was indeed a problem this was NOT the fault of the Air Ministry. The Ministry issued specifications to which the manufacturers were expected to adhere. If the wing of the Stirling was in any way inadequate this was the fault of the design team NOT the Air Ministry. This distinction is missed by many who seem to put the cart before the horse, and get things the wrong way round.
If I designed a racing car that did not meet the criteria of the formula in which I wanted to race it, then I would not be allowed to race in that formula, it's not rocket science.

In the context of the original premise of this thread, there would never be a need for folding wings, or perhaps more possibly wing tips. The wingspan limit was in place to curtail the size and weight of aircraft which seemed to be getting out of control, and at that limit there was no need to add the expense and weight of a mechanism to make it shorter.

Cheers

Steve

 

[Shortround6]

I think you will find the Sunderlands fuselage is quite a bit wider than the Stirlings.

This in addition to the top of the Stirling being straight from the rear of canopy to the tail (or slight kink) compared to the curved top of the Sunderland

 

[Elmas]

Stirling and Sunderland fuselages (almost) at the same lenght.
While I don't think that structurally the two fuselages can have much in common, some features appear quite similar: see the relative position of the wing and stabilizer. It seems that the Designer wanted to mantain the same weight distribution.

 

[stona]

I still wonder whether the Stirling fuselage was influenced by the Sunderland. Same designer(s) and there doesn't seem to be any obvious reason why it was so long.
The Stirling fuselage was around 6' wide (I haven't looked up the exact measurement), the Sunderland certainly looks wider.
Cheers
Steve

 

[Elmas]

While these are the two brothers in plan (almost..)

Personally I'm almost certain that the designers of the Stirling, while shortening the wingspan, tried to make an effort to increase the wing area, to have a "decent" wing load.

:

 

[stona]

It doesn't seem such a far fetched idea, looking at that plan
Cheers
Steve

 

[mike cunningham]

The original film was made by W.Cdr Coussins in 1944. The Squadron concerned, based at Hemswell, Lincolnshire, where in the process of having the new .50 cal rear turret fitted.
The film was originally screened on British TV in the late 1970s or early '80's, and is now available on DVD, and well worth watching for the wealth of detail and unique colour footage of Lancaster Ops.

do you have the name of the film I would like to find it?

 

[stona]

Not Airframes, but the film was called 'Night Bombers'. Highly recommended.
Cheers
Steve

 

[Airframes]

I agree.
I got my copy from Amazon, and from memory, it was around £5.
I was going to scan the case cover and post it here for you to see, but I must have left it in my camper van, and as it's been pi .... er ... persisting down heavily all day, I am not going out to the van !!

 

[Shortround6]

Well, you had a bunch of relatively intelligent men working with nowhere near the knowledge we have today.
So they based a lot of what they did on what they knew worked. Like using a horizontal stabilizer of XX% of the size of the wing at YY distance from wing rather than muck about with different distances and sizes. Closer distance means a larger area horizontal stabilizer.
This use what works approach is why many companies used similar shaped/appearing tails. A number of years experience with a certain shape and ratio of vertical stabilizer and rudder areas made them hesitant to try other shapes/ratios. See trouble with the Halifax which didn't use the size

Now both planes were being worked on at the same time, Yes the Sunderland flew first but design work on the Stirling had been going on for well over a year when the Sunderland first flew. Both planes owing a lot to the S.23 Empire flying boat/s.

 

[Elmas]

Exactly. So I don't know why do not take a well designed (for the time being, of course) wing with a suitable horizontal stabilizer and to design around it a convenient fuselage, instead of completely redesign the wing for the sake of having one of a well round number.
And with all the demanding performances that were requested by the specification, first of all a very short take-off distance.

But for more than twenty years I had to do with beaurocracy (...italian, the worst in the world, at least among the so called "developed countries"...) and I can understand.

 

[Graeme]

High wings would also exacerbate the size of the undercart I guess.
Here's the A.W.27 Atlanta - with 6' 3" diameter wheels...

 

[Shortround6]

The advantage flying boats had over land planes was essentially unlimited runway length. Trying to adapt the flying boat design to a short grass runway called for a lot of changes (grass does NOT mean unprepared, it means sod/turf on a rolled/leveled area with good drainage.)