Beyond The Sprues
Modelling => Completed GBs => Group and Themed Builds => Maritime Patrol GB => Topic started by: robunos on May 03, 2022, 03:20:52 AM
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Supermarine Stranraer Mk.2 - A One Wing Biplane
Designed to meet the requirements of Air Ministry Specification R.24/31, the original Stranraer was a larger development of the earlier Scapa. Initially rejected by the Ministry, on account of it's complex and unreliable steam-cooled Goshawk engines, Supermarine re-worked the design to use air-cooled Bristol Pegasus engines.
A prototype Stranraer Mk.1, K3973, was ordered in 1933, flying for the first time in July, 1934. Following manufacturer's flight tests, in October 1934,K3973 was delivered to MAEE at Felixstowe. It was here that the problem that doomed the Mk.1, and led to the Mk.2, first reared it's ugly head . . .
cheers,
Robin.
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Oh, looking forward to this one.
I too have a one-wing Stranraer (pixely version) in the works. Fortunately, one can never have too many Stranraers.
OT: As a kid holidaying in Penticton, I saw 'BXO flying off Skaha Lake. Truly awesome when she went overhead. They were selling joy rides but, tragically, I had squandered my nickel allowance on NOCA ice cream treats :(
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Looking forward to this one! :smiley:
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Oh, looking forward to this one.
I too have a one-wing Stranraer (pixely version) in the works. Fortunately, one can never have too many Stranraers.
OT: As a kid holidaying in Penticton, I saw 'BXO flying off Skaha Lake. Truly awesome when she went overhead. They were selling joy rides but, tragically, I had squandered my nickel allowance on NOCA ice cream treats :(
My Dad flew on the Strannies a few times between Vancouver and Ocean Falls - he worked at the Crown Zellerbach
mill in Ocean Falls and my siblings and I were born in Ocean Falls. My first flight was in a Grumman Mallard from
Ocean Falls down to Vancouver in 1964.
http://www.oceanfallsmuseum.com/CDPho/16-AirPlanes.htm (http://www.oceanfallsmuseum.com/CDPho/16-AirPlanes.htm)
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Oh, looking forward to this one.
I too have a one-wing Stranraer (pixely version) in the works. Fortunately, one can never have too many Stranraers.
Will be interesting to compare our respective versions . . . 8)
cheers,
Robin.
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Looking forward to this one! :smiley:
8)
cheers,
Robin.
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Okay . . .
Here we go!
Need to get the basic structure built, as this will guide the modifications . . .
First up, the parts for the wings,
(https://i.postimg.cc/PTVzr1xQ/01-wing-parts.jpg) (https://postimages.org/)
and assembled.
(https://i.postimg.cc/gGwywrLF/01-wings-done.jpg) (https://postimages.org/)
Likewise the tailplane,
(https://i.postimg.cc/6tpfXM9Q/01-tailplane-parts.jpg) (https://postimages.org/)
(https://i.postimg.cc/jsPzX9hM/01-tailplane-done.jpg) (https://postimages.org/)
and fins attached.
(https://i.postimg.cc/513SThWG/01-fins-on.jpg) (https://postimages.org/)
And lastly for this time, the fuselage under construction.
(https://i.postimg.cc/ZJ186Z69/01-fuselage-build.jpg) (https://postimages.org/)
That's All For Now, Stay Tuned . . .
cheers,
Robin.
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Great start Robin. And those multi-coloured Matchbox kits are always a blast from the past
Jon: Great link. I always loved the look of the Mallard but never got off the ground in one (just some avionics go-fer work on West Coast Air's Mallard). My obsession with the Stranraer goes back to Grandad's war stories.
When the RCAF moved into Newfoundland, they seem to have been short on physical plant folks. So, Grandad was transferred 'overseas' - from Ucluelet to Gander. I guess the No.5 (BR) det was short on flight crews too because Grandad spent the coldest hours he could remember in the exposed nose positions of 'Strannies' (perhaps because he was familiar with its Lewis Gun, the younger recruits would probably have been trained on the Vickers K.)
Even further OT, Ken Molson has a wonderful photo of Cyclone-powered 'Super Stranraer' CF-BXO taking off from Abbotford on a dolly. Does anyone know how 'BXO got to YXX in the first place?
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All I can figure is that BXO must have been trucked to YXX. Nothing else makes sense. ;)
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Okay . . .
Got a bit behind with this one, but finally some progress.
The fuselage / hull complete . . .
(https://i.postimg.cc/Zm7VmSp1/02-fuselage-done.jpg) (https://postimages.org/)
The bow hatch can be modelled in the open or closed position. I decided to model it closed, but if one does, there will be poor moulding visible,
(https://i.postimg.cc/37z1yFL1/02-nose-bad.jpg) (https://postimages.org/)
I fixed this by adding a piece of 10 thou plastic card.
(https://i.postimg.cc/DFS5yMcm/02-nose-fixed.jpg) (https://postimages.org/)
As can also be seen, there was quite a bit of filling required around the dorsal gun position.
Finally for this time, the wings and tail attached.
(https://i.postimg.cc/GL5QxFbc/02-wings-plus-tail-on.jpg) (https://postimages.org/)
Next up will be the engines ( and this is where it gets really interesting . . . ;) [size=78%])[/size]
That's All For Now, Stay Tuned . . .
cheers,
Robin.
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I still have a very soft spot for Matchbox kits, nostalgia for when they and their excellent subject choice first came out.
This was one kit I had to have and it took years to actually get one.
Still have it. In the box :-[
Great to see this build progressing.
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Odd. ???
The pic with the wings attached threw me for a moment because, I realised shortly after, I was visualising this build as a parasol-wing design! :-\
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Looking good Robin :smiley:
... Next up will be the engines ( and this is where it gets really interesting . . .
Oh, you tease! But patiently we will wait ... :icon_meditation:
... I realised shortly after, I was visualising this build as a parasol-wing design! ...
Interesting that you should mention a parasol ... ;)
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Odd. ???
The pic with the wings attached threw me for a moment because, I realised shortly after, I was visualising this build as a parasol-wing design! :-\
I looked long and hard at a parasol version, but it created practical problems with making the model, that I couldn't resolve to my liking. Besides, the version I'm doing leads to a better backstory and ties in to some future builds . . . ;)
cheers,
Robin.
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. . . This was one kit I had to have and it took years to actually get one.
Still have it. In the box :-[
They're getting hard to come by now . . . and therefore expensive. :o
cheers,
Robin.[size=78%] [/size]
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A critical requirement of Spec. R.24/31 was the ability of the aeroplane to maintain height with one engine shut down, and unfortunately, the Stranraer was unable to do this.
It wasn't a lack of power that was the problem, more powerful engines were available, and indeed tried, but some unknown characteristic of the Stranraer's configuration meant that it was impossible to trim out the yaw and resulting wing drop that developed with one engine shut down. Various changes to the engines' position were tried, both fore-and-aft, up and down, and sideways, along with toe-in and out, to no avail. Likewise, various combinations of enlarged and re-positioned fins and rudders were also evaluated, with the same negative results.
Finally, under pressure of both finances ( nothing had been noted officially, but a 'gentleman's agreement' had been put in place for a production contract to follow the successful completion of the Stranraer's trials ), time ( if the aeroplane did not prove satisfactory before the end of 1935, the production contract would be withdrawn ), and resources (development of the Type 300 fighter, the Spitfire-to-be, was ramping up, and Design and Technical Office staff were needed for this, rather than the 'already designed' Stranraer ), in semi-desperation, RJ Mitchell authorised a limited redesign to fit tandem engines . . .
While obviously advantageous, as of course, the wing drop problem disappeared, and with the engines mounted above the hull, the engines and propellers were shielded from the spray when taking off and alighting ( surprisingly, the metal Fairey-Reed propellers then in use proved to be much more prone to spray damage than the wooden propellers used previously).
In addition, a ready designed pusher engine installation was available, in the form of that used on the Seagull V / Walrus, although in this case the engine would be fitted with a cowling.
However, there were downsides. The rear engine later showed a tendency to overheat, and with the engines now on the centre line, the twin fins and rudders were robbed of their slipstream. However, a redesign of the tail to incorporate a centre line fin and rudder was deemed impractical ( the tail gun position would need to be revised, meaning alteration to the rear of the hull, and the tailplane structure would need to be redesigned and re-stressed ). Also, the new rear propeller was uncomfortably close to the dorsal gun position, and moving this aft would involve too much work ( production jigs and tooling for the hull had already been constructed, upon receipt of the aforementioned 'gentlemen's agreement'. )
Nevertheless, the go-ahead was given to reconstruct the prototype Stranraer into the new Mark 2 form.
cheers,
Robin.
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One wing appearance looks normal, top wing not missed.
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One wing appearance looks normal, top wing not missed.
Thanks . . . :D
Okay . . . So, engines. First choice as always is to use the base kit parts . . . but as you can see below, they won't be suitable, especially for the pusher engine.
(https://i.postimg.cc/SkNSg7sh/03-engines-cant-use.jpg) (https://postimages.org/)
The cowling is the wrong shape, and the engine is the half-relief on a disc type. Fortunately, I have a project in the planning for some Fairey Swordfish variants with different engines, so I have a couple of them spare, and they're perfect for this Build. Because of the way they're tooled, it's also easy to make both pusher and tractor versions . . .
(https://i.postimg.cc/7qjqPFNH/03-engines-ready.jpg) (https://postimages.org/)
So, we're going to need a nacelle to mount the engines to, and a pylon hold said nacelle above the fuselage. These will be created through the magic of 3-D printing. So, after CADding them up, I printed them out. But while the printer was chugging away, I made up the wing floats, and made and fitted their supports, from scrap pieces from the Spare Wing Box . . .
(https://i.postimg.cc/PXjhY1c0/03-wing-floats.jpg) (https://postimages.org/)
Here are the pylon and nacelle, fresh from being printed and cured, each still attached to it's 'foot',
(https://i.postimg.cc/Hp5dr6SQ/03-pylon-and-nacelle.jpg) (https://postimages.org/)
and with the 'foot' trimmed away. the bottom of the pylon will need some more trimming to fit on to the upper hull.
(https://i.postimg.cc/Dnj2HJJb/03-pylon-and-nacelle-trimmed.jpg) (https://postimages.org/)
Finally for now, the nacelle dry-fitted to the pylon, to show how it will look when assembled . . .
(https://i.postimg.cc/t9sXjqWv/03-nacelle-pylon.jpg) (https://postimages.org/)
That's All For Now, Stay Tuned . . .
cheers,
Robin.
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Very cool. But, oddly, the nacelle has me seeing French ;D
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Okay . . .
So it's time to stick all the bits together . . .
I made a fitting from some scrap runner, to help position the pylon on the hull top, and attached it.
(https://i.postimg.cc/PhTHPVtz/04-pylon-brace.jpg) (https://postimages.org/)
While that was drying down, I glued the pylon and nacelle together.
(https://i.postimg.cc/SkQmtT3N/04-nacelle-pylon-joined.jpg) (https://postimages.org/)
I've found that you can use the 3-D printing resin to glue the resin parts together. It has no 'tack', so you have to hold the parts together in some way first, I used tape, and then I used a fine brush to run some of the resin into the joint, wiped off the excess, and then cured it. It seems to work, at least for small parts . . .
Lastly, I attached the pylon / nacelle to the hull, and the wing floats under the wings. I drilled matching holes in the float struts and wing panels, and used cut down dressmaker's pins to align them. I also added the windbreak in front of the dorsal gun position. There are a few detail parts still to attach, then it's off for painting.
(https://i.postimg.cc/DnC7VQ3Q/04-assembly-complete.jpg) (https://postimages.org/)
That's all For Now, Stay tuned . . .
cheers,
Robin.
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Wow! Great job with the printing! And I love how this is coming together! 8)
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Sadly, I think I might need an extension . . . I'm just not getting any time for model making at the moment.
Painting's done, decals are on but not sealed, but I still have all the fiddly stuff to do . . . :( :icon_sueno:
cheers,
Robin.
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And we're finished !
Supermarine Stranraer Mk.2, RAF Pembroke Dock, 1937-8.
(https://i.postimg.cc/ryXj55CN/Stranraer-G.jpg) (https://postimages.org/)
(https://i.postimg.cc/69PY5k8S/Stranraer-B.jpg) (https://postimages.org/)
(https://i.postimg.cc/MqwtTbGW/Stranraer-K.jpg) (https://postimages.org/)
Following the authorisation, the alterations were quickly carried out, and the modified aircraft was re-submitted for testing. On 29th April 1935, the aircraft was deemed satisfactory, thereby triggering the 'gentleman's agreement', and with it a production contract.
However, due to the delays, and a few, minor, niggles still remaining, the quantity ordered was only 18 airframes, rather than the expected number, of at least double this. The balance of the order was given to Saro for their A.36 Lerwick, it being judged a later generation, and therefore superior, design.
As is now well-known, however, the Lerwick turned out to be even worse than the Stranraer, with the end result that both were eventually replaced by the US designed and built PBY Catalina.
Ironically, the expected rear engine overheating turned out not to be a problem, as the Stranraer only operated in Home Waters, there being insufficient aircraft to allow them to serve in the Empire . . .
More pictures in the Gallery thread.
That's All, Folks . . . . !
cheers,
Robin.
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:smiley:
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That came out great, but the engine placement screams "Italian". I think the rear prop pitch is backwards, though
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:smiley:
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Nicely done Robin. Your Strannie Mk.2 is a real looker :smiley:
... Ironically, the expected rear engine overheating turned out not to be a problem...
... but the slipstream from those twin centreline radials did require the installation of goolie-heaters in the aft open gun positions :o
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Really looks the business, nice one :smiley: :smiley:
Mog
>^-.-^<
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Thanks for the comments, Gents . . . :-[ :D
@Frank; I wouldn't know if it was itallan or not, but I did make a thorough study of both of the books about Supermarine projects and prototypes written by Ralph Pegram . . . and yes, the rear prop is backwards, I just used the props that came with engines, and hoped that no one would notice . . . :smiley:
@apophenia; that was one of the 'few, minor niggles'. As well as being cold and draughty, the strong slipstream interfered with gun aiming from the dorsal position, so much so, that the position was not manned unless absolutely essential, which in peacetime, meant never . . . the tail position was not as badly affected, however, so was occupied when necessary.
cheers,
Robin.
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The rear engine is a little better exposed to the slipstream than a lot of similar designs, so it might well have gotten adequate cooling. I suspect the Admiralty would have insisted on mounting the wing to the pylon rather than the hull, though - "Aerodynamic efficiency? Harumph. I said HARUMPH, Sah!" Great looking build.