Robert Parker Posted May 21, 2014 Share Posted May 21, 2014 Hi All, I have made a start on drawing a Short Stirling for two reasons. Firstly, there is something about it that makes me want to make one and secondly, following an accident in which I have broken my thumb and forefinger and my right hand is in a plaster cast and there is very little else I can do at the moment. It is also very much the forgotten bomber of WWII, it was in fact the first 4 engined bomber to enter service that was designed from the outset as a 4 engined bomber unlike the Lancaster. However, it did have it's problems, unreliable engines and a very complex landing gear, in fact the first prototype the gear collapsed on the first landing. It had several roles during the war from bomber with a very limited bomb bay in way of modifications unlike the Lancaster, troop carrier & glider tug. Back around 1999 / 2000, I drew a design on computer and built a 65" model to be powered by a quartet of speed 400's. However, I never completed the project and the model was scrapped. I still have the drawings on disc and the programmes. However, having tried a Dos emulator I could not load up the programme because I did not have the serial number and another programme would not find my printer. So this time around I didn't want to buy and learn a new programme. So I am going back to the old fashioned way of using a roll of lining paper and dusting off my old tech drawing equipment from my college years back in the 80's and away we go. I have gleamed some reference material from the net, if you look up short stirliing on you tube there is a 10 foot model with scale undercarriage and flaps, must say that chap who made that landing gear to scale made a great effort of engineering achievement and well done who ever you are. Some photos and an old 1/72nd Airfix kit that I built for info on my first effort. What am I aiming to achieve? Well I have built a 72" Lancaster designed by Tony Nijhuis and it needs a stable mate. I am currently in mid build with his Beaufighter and it is going well so far until my accident. I have a build blog of it so far. At 73" span the Stirling will fit nicely into my car and at that span it works out at 1/16th scale so the maths are a bit easier. The model will have 5 functions although the retracs will not be scale in operation, my skills are not that good by any means. Power will be four electric brushless motors. I had thought about using the wing from Tony's Sunderland but it was too different in many ways, that said, I have used some of the techniques used on the Sunderland for the design of the nacelles. Span: 73" Length: 66" Functions: Ailerons, elevator, rudder, speed controller and retracts Weight: ???? as light as I can make it aiming to be roughly the same as my lanc some photos of progress so far. All ready to start, I've got 5 hours before the family get back from work & school. Not too clear, but the fuselage drawn in elevation and plan with most formers, cockpit, gun turrets 3 off, radio mast, fin, wing position marked out there are going to be some interesting curves at the nose to sort out when the build starts The wing plan, I had to extend the width of the paper a bit, root rib nearly 17" long. The original plane had a fillet at the back of the wing long the trailing edge, which is very characteristic of the plane and after some thought I am going to recreate with some ply attached to the fuselage this makes making the wing a lot easier. Two sets of spars and wing braces to both sets extending to the inner engines. Tailplane and elevator plan, inner and outer engine bays cross section, front elevations of the inner and outer engines plus a cross section of the wing. I have come to a stop on the retracts for the moment, I need to spend some time head scratching on the gear position and leg length. Close up of the engine nacelles and I have a made a little error with the cowl length on the outer engine, I noticed this after I inked it in. Finally, a cross section of the front of the inner nacelles, lots of curves again. I have spent around 12 hours on this so far over the last three days. I would welcome any views and comments on this design. Regards Robert Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted May 21, 2014 Share Posted May 21, 2014 beautiful drawings sir. i thought about the stirling but decided on the shackleton instead. will be watching this with great interest sir. Quote Link to comment Share on other sites More sharing options...
Ton van Munsteren Posted May 21, 2014 Share Posted May 21, 2014 Nice o yes I will follow this design and build, always liked the Stirling. Ton Quote Link to comment Share on other sites More sharing options...
Lindsay Todd Posted May 21, 2014 Share Posted May 21, 2014 Very nice, its a classic design that is truly deserving to be modelled, I shall be following progress keenly. Linds Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted May 22, 2014 Share Posted May 22, 2014 That's great Robert. The general proportions of the Stirling almost guarantee a good flyer. Although it had its' limitations operationally, it flew well and was considered to be very maneouverable for a four engined heavy. As you say, any compromise has to be in the undercarriage. If you do it as a glider tug version you could team up with Dylan Reynolds and his Albermarle and toss a coin to decide who will build the complementary Horsa! Hopefully I've got something brewing that will interest you as well, I think. Should be able to get started on it shortly. Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted May 22, 2014 Author Share Posted May 22, 2014 Hi All, Thanks for the encouragement. As I mentioned above this has been in my mind for quite some time now and I have no excuses until my hand heals, then I'll have three projects on the go, the stirling, the beaufighter and a p40 which needs painting and some tlc. I can only spray paint in the garden due to the odours. I'll be pressing on with the drawings, though the wife is off work tomorrow and the kids off all next week so she'll have a say on what gets done on the worktop. I have done some more work on the drawings and focussed my attentions on the fuselage construction, not fully completed this task today but I have gone a combination of sheet, strip and planking but I'm getting an idea of how it's going together. Front set of formers I have not finished need to add the fuselage sides top and bottom. you can just about make out the dark arrows showing the sheet and the junction where the planking takes over the nose section, I thought it would be easier to bend the planking around the curves particularly around the front turret position. The main formers for the bulk of the fuselage I'll be using 3/16" for the bottom sheeting cross grain, 1/4" for the sharp curves of the bottom section, after some thought I have tapered in the sides maybe a bit too much but my airfix model shows a slight taper (it was a little temping to make a straight forward box section) with a long curve top so in trying to keep things a little simple the sides are 3/16" x 4" sheet and for the rest of the upper section and top I'll use 3/1^" planking. I envisage building the fuselage as follows: Cut out and splice the two sides, glue the main formers F4,5 & F8 & 9 as these are all the same size to one side, then place in my jig and glue the other side in place. When dry invert the fuselage in the jig and build the bottom, then fit the tail feathers then plank the rest staggering the joints in the planking to avoid any weak spots. Mid turret and sheet splice joint 36" sheet shown Rear turret and fin and not forgetting the double tailwheel. I have increased the fin and rudder slightly as they are not in any prop wash. I'd rather reduce the throws than wish I had more. Can I ask you all for some advise for the choice of aerofoil best to use and the angle of incidence. I have downloaded the demo version of Compufoil which I have done the wing plan form but a bit stuck on the choice of aerofoil, I'm a bit lacking in knowledge in this area. My airfix model seems to show quite a high angle of incidence of the main wing against the fuselage, I realise that the full size flew with it but I'm concerned about inducing a stall at take off. Any thoughts please. I look forward to reading your replies. Regards Robert Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 22, 2014 Share Posted May 22, 2014 Robert If I was doing it I would use the scale wing section, Goettingen 436 (mod), for no real reason other than it would be scale - but then I have a bit of a 'thing' about non scale wing sections! The modification was apparently to 'thicken' the wing slightly but I can't find out by how much. The basic Go436 section has a reasonable 11% t/c ratio at 30% chord and a flat bottom from 10% chord so would be simple to build. **LINK** Finally I not sure the increase in tail area was really necessary with the Stirling's relatively long tail moment. **LINK** Just my opinion but keep posting I shall follow with interest. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted May 22, 2014 Share Posted May 22, 2014 I agree with Simon on this one Robert. I would build it to scale aerodynamically, wing section and thickness, tail areas and angle of incidence. The original was generally stable and viceless from what I have read and the best way to reproduce that is to duplicate the original. Perhaps the one point that I might be thinking about would be whether or not to build in perhaps two degrees of washout. Looking at drawings of the Stirling I note that the tailplane is set at a positive angle of incidence, perhaps two or three degrees? This offsets against the incidence of the wing and accounts for the slight nose down sit of the plane in flight, I imagine. If you did build in any wash-out which did in in effect reduce the incidence of the wing, you could compensate for that by adjusting the incidence of the tailplane. However, I'm not sure whether the wash-out is essential, although it may be helpful. You mention that you considered using the wing from Tony Nihuis's Sunderland. If I remember correctly, when that was published in RCME, Tony said that he had used the wing from his B17, because it was similar. Although similar, it isn't the same and personally I don't think it looks quite right, although it is a matter of opinion. I'd do what you are doing and design it from scratch. Good on you mate, this is a brilliant project. Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted May 22, 2014 Author Share Posted May 22, 2014 Thank you both for your replies, Simon, thanks for the wing section I should be able to scale it up from the link. I agree with you on the long tail moment. It was just a belt and braces moment. I'll get the tipex out and have a redraw. The second link you posted is great it does show how big the Stirling was in compared to the Halifax and Lancaster at similar wingspans. Colin, I had put 2 degrees of washout on the wing when I used the compufoil programme. However, the wing section I used in the programme was an Eppler 205. You are correct to say that the Sunderland was published in the RCM&E and I must admit it does look a little thin. I take on board both of your comments and will stick with the scale sizes etc. Once again thanks for your comments. Regards Robert Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 23, 2014 Share Posted May 23, 2014 Apparently although the construction of the Stirling's wing was identical to that of the Sunderland it had a reduced span of just 98' compared to the Sunderland's 135'. In 1941 Short proposed an improved version using the 135' wing planform and Bristol Centaurus engines which would have put the Stirling virtually in the B29 class. Although 2 prototypes were ordered they were cancelled in favour of Lancaster production. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted May 23, 2014 Share Posted May 23, 2014 Robert, have you got "The Stirling Story", by Michael JF Bowyer? It is excellent and I'm sure you would find it helpful. Here are a couple of extracts, one of which shows the projected "Super Stirling" that Simon refers to. The other one which shows the camouflage pattern also clearly shows the marked positive incidence on the tailplane. If you put two degrees of washout in the wing, you are reducing the overall incidence by one degree and you can compensate for that by reducing the incidence on the tailplane by one degree. Overall you'll be preserving the general aerodynamics of the original and giving yourself a bit more insurance against possible tip stalling tendencies. Perhaps the full size had some washout built in, but I can't find any reference to it. Are you going to try and reproduce the Gouge flaps? I don't think I could be that heroic, but you might be! Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted May 23, 2014 Author Share Posted May 23, 2014 Thanks Colin, no I have not got this book, I've found it on both Amazon and e-bay plus some other interesting items. I had not heard of the "super stirling" though. No I'm not even going to try those flaps way too complex for me and my modest workshop. Have you looked up "short stirling" on you tube? There is a 10' span or so model that has been built with scale undercarriage and working flaps, worth a look just for the engineering that's involved. Regards Robert Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted May 23, 2014 Share Posted May 23, 2014 Thanks Robert, I'll take a look at that. You will see that I've started a thread for a brother for your Stirling, which makes it even more interesting. You're using 1/16 scale, I'm using 1/17, so they'll be pretty close to each other. Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted May 23, 2014 Author Share Posted May 23, 2014 Hi Colin, I've just read your thread on the supermarine 317 and thank you for the mention. It looks an impressive aircraft. Your reference material looks very good, an excellent book I must say. I was looking through one of my books last night and found a photo of an interior view of the stirling and the fuselage sides are quite notably tapering so I'm not that far off by the look of it. What I would like to find is some cross sections and I think that I may have tracked something down at Amazon when I was looking for your book, I'll keep you posted Regards Robert Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted May 23, 2014 Share Posted May 23, 2014 You know some stuff you lads, I wish I had the ability to sit down and draw the likes of this up. I will have to settle for watching. Great project Robert. John Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted June 2, 2014 Author Share Posted June 2, 2014 Hi All, I'm returning after a weeks holiday in sunny Cornwall (well most of the time). Whilst there I was treated to seeing a DH Chipmunk and at a distance a DH89 Rapide (I believe) taking off from Newquay airport. During that time my mind has not been at rest and on my return I received some more detailed information as well as trawling the net. Today, I have re-drawn the fuselage formers. I was not happy with them being tapered and unearthing some drawings on Google along with my new info I decided to have a re-draw with the formers aft of the cockpit being altered. This re-design does away with the planking and will speed up the build. I have also checked the tail group and they are now to scale. I'm starting to look forward to the build but more drawing to do first. Regards Robert Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 2, 2014 Share Posted June 2, 2014 This is worth waiting for. I'm looking forward to following your progress Robert. Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted June 2, 2014 Author Share Posted June 2, 2014 Hi Colin, I am pleased with how well the drawings are progressing and these are much better than my first crude attempt 15 years or so ago. It's just a pity that I am doing it the old fashioned way and not on CAD or similar at least I can see it full size on the breakfast bar. It will certainly have a "presence" in the air. Regards Robert Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted June 2, 2014 Share Posted June 2, 2014 looking spectacular sir. looking forward to the first build pictures. Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted June 2, 2014 Author Share Posted June 2, 2014 Hi Tony, I want to get the Beaufighter off the bench before I start the Stirling. Regards Robert Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 2, 2014 Share Posted June 2, 2014 Presence it will certainly have. Quote Link to comment Share on other sites More sharing options...
Plummet Posted June 2, 2014 Share Posted June 2, 2014 I met a chap (at a relation's funeral) and we got talking. He had flown in Stirlings, and would not hear a word said against them. He told me that what problems they had were do to the insistence that their wingspan be chopped so that they would fit into a standard RAF hangar. This lead to their undercariage being lengthened to increase angle on incidence for take off and landing, Plummet Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 2, 2014 Share Posted June 2, 2014 He must have some great memories. Mind you, he was lucky. Out of the three heavies, the Stirling was the one you were most likely to die in. It had the worst crew survival rate because of poor altitude performance, it was often stuck down in the flak. The Lancaster had the best crew survivor rate, the Halifax was between the two. Quote Link to comment Share on other sites More sharing options...
Plummet Posted June 2, 2014 Share Posted June 2, 2014 Well it seemed to work for him? There are people who love Trabants, Fords, Vauxhalls, Citroens, Moggie Minors, Porches, Rollses, Minis, (and on and on and on...) Logic not expected. Plummet p.s. I am included in one of the above. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 2, 2014 Share Posted June 2, 2014 It was a great plane, I've always liked it. Apparently it flew very well and was maneouvarable, but the altitude issue was it's Achilles heel, apparently. Can't wait to see this model, it isn't done enough. It's a great shame we don't have a real one surviving. Edited By Colin Leighfield on 02/06/2014 23:43:11 Quote Link to comment Share on other sites More sharing options...
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