Design & Build Short Stirling

[cymaz]

Posted by Robert Parker on 28/10/2014 20:56:27:

Thanks both,

I must admit this has been a little slow to get started, I do like to finish one project before I start another and the Beaufighter has been clinging onto the building board for a little too long now, I been let down by one supplier for my decals and the other put the wrong ones in my letter, all being sorted out now.

My better half has informed me this evening that the forth coming maintenance tasks for the next year are somewhat extensive and involves me to re-locate my work room to the attic. I have dragged my heels a little on that score in finishing off the attic flooring and enlarging the hatch. I'll do these attic before any serious building starts. Just where to put everything in the transition!! and how do you get an 8' x 3' building board through a 2' sq hole without cutting it.???

 

Regards

Robert

 

Hell, I don't think I would fit through a 2' square hole!

(I'm in great shape-round is a great shape)

Edited By cymaz on 09/11/2014 08:34:45

[Robert Parker]

Hi All,

Made a start on the fin and rudder today, a very special moment turning my drawing into an aircraft.

I'll sheet the fin in /16th and fit the ribs to the other side of the rudder

Back to the drawing board

Regards

Robert

[Colin Leighfield]

From little acorns do mighty oak trees grow, the start of something big!

Purely for interest Robert, the December 2014 edition of Aeroplane features the Lancaster Mk2, the Hercules engined variant of which only 300 were built. The conversion from the Merlin was done by using the Hercules "power egg" that had been developed for the Beaufighter. There are some great photos showing the engine installation you might find interesting in view of your Beaufighter build. Also of course the Stirling used the Hercules, although I don't think the installation was the same. It's a great read.

[Robert Parker]

Hi All,

Just thought I'd share this with you, I have completed the fin and rudder came out at 22g. Well pleased with that.

Thanks Colin I'll pick up a copy when I'm next in town.

Now it's time to turn my attention to the tailplane and elevators and give them the same adding lightness treatment.

Just a thought, can anyone suggest a good lightweight covering that can be readily painted. I did try Solarlite (possibly the worst covering I've ever used and the paint did not take even with prymol primer) on my Lancaster a few years ago.

Regards

Robert

[Trevor Rushton]

I am very impressed Robert; looking good. I'm a fan of glass fibre and interior varnish as a coating although it takes quite a few coats to fill the weave; mixing talc in makes it easier. Poly C or Ezecoat are similar but probably more expensive.

Whilst it won't help your build I'd thoroughly recommend reading "a Thousand Shall Fall" by Murray Pedden; it recounts his experiences learning to fly and subsequently flying Stirlings from Norfolk, brilliant book.

[Mike Etheridge 1]

I went to the Solent Sky museum in Southampton last week where a Short Sandringham plane is exhibited. The plane is actually a converted Sunderland and was once owned by actress Maureen O'Hara (Now 93) and her husband. I assume the wings and engines match those used on the Stirling ?

I would recommend a trip to the museum where they have a huge display of old models and kits apart from the full size aircraft. However they have been investigating unusual happenings over the last within the building so it could well be haunted, something that has been reported at another museum where a ghostly pilot tries to keep the public away from his Vampire or Venom ?.

 

Edited By Mike Etheridge 1 on 11/11/2014 09:32:58

[Colin Leighfield]

Hi Mike. as I understand it, although the Stirling wing is similar to the Sunderland, it's not the same. Also, most of the Sunderlands that saw service in the war had Bristol Pegasus engines, a few MkVs late in the war entered service with Pratt&Whitney Twin Wasps. The Stirling always had the Bristol Hercules, albeit in different versions. Hercules engines were fitted in the final version of the Sunderland, re-named the Seaford, but only a few were built.

As a kid I remember visiting Pembroke and seeing RAF Sunderlands moored in the harbour. They were withdrawn in 1958 and it must have been about then. Shame there's no Stirlings around to look at, but I remember that when I visited RAF Shawbury around about (1961)? with the ATC, there was more than one Stirling parked up there. They must have been scrapped shortly afterwards, no one bothered about saving them in those days, a great shame.

[Mike Etheridge 1]

Thanks Colin , that tidies up the wing and engine issue of both planes.

When I started work in 1965 my team leader (Mac McLening) was always keen to share his wartime experiences with RAF rescue boats which were based at Pembroke Harbour with the Sunderland aircraft. He taught radio communication at Cranwell during the war also. Mac claimed to be deaf in one ear as result of his Sunderland trips which also took place in Scotland.

Mac's most amusing story concerned a bomber that had ditched and was floating in the sea with the crew on board. A Walrus plane was sent out to rescue the bomber crew which it did but could not take-off as the sea blew up too rough. Mac's rescue boat was then called out and eventually approached the Walrus but the choppy sea caused the Walrus wing to break through the side of the boat . They all then had to be rescued by a Destroyer after which it was obliged to machine gun and sink the rescue boat and Walrus to avoid them being salvaged by the enemy. I wonder if there is a record of this action ?

[Colin Leighfield]

It will be somewhere Mike, it's just having the time to do the search in records for ASR.

[Robert Parker]

Hi All,

Very interesting stories and the Solent museum looks great though I'm not sure if I'll get down there any time soon. Although they do have a Sunderland museum in Pembroke dock which I have been meaning to pop across to.

Well things are moving on a bit with the Stirling and I now have all of the major mechanical / electrical bits I need to complete the project, I'eve never been so prepared this early on in a project before.

I had a bit of luck the other day when I saw a set of retracts on e-bay for half the retail price, they have not been used, just two of the legs shortened which is no problem for me as I'll be making my own, the seller even included a pair of oleos to suit a P51. Next project????

I've even got one unit left over!!! What about that B25 in the attic..... I'll put safe for now. One model at a time now.

I have tested the units, they work perfectly and have no signs of being fixed, not a mark on them.

This evening, I made a start on the tailplane cutting out the ribs and the leading and trailing edges, being a symmetrical tailplane I marked both the leading and trailing edges with a center line plus the ribs and glued them up

When dry I'll add the remaining center rib using the fin as a spacer.

That's all for now

Regards

Robert

[Tony Bennett]

lovely sir

just lovely

[Colin Leighfield]

Robert, I don't blame you for not trying to build a scale undercarriage!

[Simon Chaddock]

Robert]

Note that the Sunderland had a span of 112' 9" whereas the Stirling was 99' 1" however the area was little different 1487 sqft against 1460 respectively. The Stirling thus has a broader lower aspect ratio wing than the Sunderland.

It does seem odd that Shorts should do this and their original S29 proposal did indeed specify the Sunderland wing but the 100 ft span a rather short sighted limit imposed by the air ministry to force designers to keep down the maximum weight.

The tale about being limited by hanger doors is simply not true as they had 112ft. openings and in any case servicing was done outside.

[Robert Parker]

Thank's Tony.

Colin, No that mechanism is way beyond my mechanical capabilities. I've have opted for scale length so she will stand tall and proud.

Simon, I was aware of the wingspan difference but now aware about the hanger doors size limitations not be untrue.

Regards

Robert

[Robert Parker]

Hi All,

I have completed the tailplane, elevators, fin and rudder. By using the lightest balsa I could find the whole assembly weighs a mere 67 grams. My Beaufighter's tail assembly was 90g a whole 23 grams lighter and considering it's actually bigger in span and height I think it's pretty good so far in weigh saving.

Well I'm now thinking on going back on my previous statement about not starting anything too big prior to moving my model room up to the attic. Mt temp building board is only 4ft long, the fuselage is over 5ft long so I must start the fuselage now, shouldn't I. Also each wing panel is 3ft long, so it's the next logical step.

I'm going back to the drawing board to make sure I'm happy with the outline and the formers and doublers.

That's all for now

I'll keep you all posted

Regards

Robert

[Colin Leighfield]

You'll do it!

[Robert Parker]

Hi All,

I have just finished cutting out all of the formers and joined the fuselage sides, OMG what a beasty this is going to be. It's one thing seeing the plan rolled out on the breakfast bar but on the workbench well it's something else plus I had to add an inch onto the 4 inch sheeting as it was not wide enough!! did not notice that when I ordered the wood.

13 formers cut by hand no CNC here. Splice joint to the 48" balsa. Thank goodness the fuselage only tapers at the two ends my building jig would not be long enough otherwise.

Marked out the cutouts for the wings

Back to sorting out for the move into the attic, moving slowly bit by bit

Regards

Robert

[Robert Parker]

Hi All,

Things are moving on now, albeit with a couple of alterations / re-drawing, I had to re-do the rear formers as I was not happy with them and also the nose section needs a little of adjustment but nothing major.

My original thought was to have the front section planked from the rear of the cockpit to the but having looked at the curvatures I decided to extend the sides up to the rear of the front turret. It will still be planked from the front of the cockpit to the front turret where there are some tight curves.

Some photos of progress so far

With 5 formers identical in size starting off the fuselage is just like a trainer, I added a lit-ply doubler

The front formers before a slight alteration

Taking shape, that's a 48" melamine fuselage jig!!

Looking down the fus as the Beau pilot keeps a close watch

Bags of space for the two servos at 4 1/2" wide inside face to inside face

Getting ready for the rear end build. Note the roll of A0 paper 50m for £10 on ebay, I'm using this to draw the "as built" plan.

I spliced the front section to save a bit of time planking these joint will be reinforced.

Just put together the rear end this morning. The length of the fuselage is 64" or 1.63m including the rear turret.

Next I'll concentrate on the front area and make a couple of modifications as well as continue with the sides.

That's all for now.

Regards

Robert

[Robert Parker]

Hi All,

In pursuit of things being right before I progress any more with the fuselage I am stopping here and re-building it.

I would rather do this than try to convince myself it'll be alright when I know / feel that something is not right, and if it's not right, then it's not right. At this point in time in the build it is just a couple of sheets of 1/8th balsa, so the cost is low of abortive work

I have had my doubts for a couple of days but not have sufficient time available to investigate in great detail to see what, where and how it had gone wrong and how can it be put right.

It all came to light this evening when I had intended to fit the upper fuselage sides and the rear sections were needing to be twisted to fit all of the formers on one side whilst the other side only touch the rear former and F9.

Rather than build a twist into the fus I traced back where I had gone wrong and it was a pretty basic error on my part. RUSHING and not paying attention to detail when I was putting the sides together and a couple of formers were not exactly in their correct position and with such a long fuselage a small error can be a large error 3 feet away.

The positive side of this is that I have the benefit of hindsight on the second build and can incorporate the modifications made so far.

Silly mistake but easy to put right just lost a little of momentum. I'm keeping the old one for reference for now.

What I might do is to chop off the top sections of the formers so the fus can lay flat on the building board hopefully eliminating any twist and then add them after sheeting the bottom to lock the whole structure before it leaves the board. It does seem very flimsy at the present.

Regards

Robert

[Colin Leighfield]

Right thing to do Robert, it will be worth it in the end.

[Robert Parker]

It has to be done Colin, just had to face up to it before it got too late.

[Tony Bennett]

best idea.

sometimes it is better to start again than build in a problem that needs sorting further on in the build.

[Terry Walters]

Good decision Robert - you'll have a much better feel about it than leaving it.

Terry

[Robert Parker]

Hi All,

Well I now have a fuselage that I'm happy with. I'm now working on MKIII. There was me thinking that the error was in the building and to some extent it was with such a long fuselage a small error in alignment at one end can throw things way off at the other end. With MKII I simply made new formers from photo copies off the drawing. After gluing the first set of formers in position and about to start with the aft formers the same twist was apparent. MMMMMMMM I thought and checked the drawing of each former and found that a school boy error had crept in on the common former which there are 5 of them, my "T" square could not have been true to the worktop and so I had managed to produce a leaning former, not by much only 1/16th or so but it made a massive problem at the tail.

So I have re-drawn the formers from F1 to F13 on computer and printed these off and stuck them on the balsa cut out and all fitted well.

The ill-fated MKII formers

The new and improved MKIII formers

Assembly once more

Note the new approach, inverted and on blocks, no twist this time

Ply battery compartment

The modified nose section

Finally, reached the same point as three weeks ago, razor plane at the ready then the top sheeting can be fitted along with a trial fitting of the tail group.

Well I have just found out that the chief test pilot for Short Brothers, John Lankester Parker first flew the Stirling along with Hugh Gordon. I can't seem to find out much about him except that he was born in 1896 and first flew in 1914 at lake Windermere, and retired in 1945.

I wonder if we might be related?

Regards

Robert

[Colin Leighfield]

You never know Robert! All the more reason for building a Stirling. Sadly I can't find any famous aviators called Leighfield. I did have an uncle who was a PT Instructor in the RAF and I know that he had a few trips in the back of Boulton Paul Defiants. However that one is fairly well down my list of priorities, even though I like it!