The Martin PB3M-1 Master Mariner

jcf · July 22, 2024, 09:47:52 AM

Quote from: zenrat on July 21, 2024, 04:28:41 AMMinicraft, not Academy would have engineered the moulds given it's originally their kit.

I regret not getting one of these even more now i've seen your sprue shots.
If I can engineer a gull wing INTO a B-25 wing you can definitely engineer one OUT of a Mariner.

If a Master Mariner flying boat was used to lure enemy fighter aircraft into a trap would it be a Master Baiter?

I'll get me coat...

Academy did the moulds, Minicraft never had its own engineering department. It wasn't a model company in the sense of Airfix, Revell, Hasegawa etc.

zenrat · July 23, 2024, 05:53:30 AM

Well you live and learn. Were academy responsible for all Minicraft or did they buy in from various places as needed?

PR19_Kit · July 23, 2024, 06:37:56 AM

Quote from: Old Wombat on July 21, 2024, 09:59:40 AMI can't see why you can't just have the rise of the gull-wing continuing through the inboard engine nacelles to the outboard engine nacelles, Kit.

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Structurally that would work, so long as I used the vacform outer wings I think. The injection ones may be too heavy for the vacform gull section to support.

But there's a more fundamental problem, the prop clearance. With one gull wing section the props just have to clear the fuselage, but add another gull wing section and it needs to be almost TWICE as long the original one or the props will hit each other, probably NOT a good idea............

Rick Lowe · July 23, 2024, 10:51:10 PM

Have the inner engine mountings staggered ahead of the outboard stations.

PR19_Kit · July 24, 2024, 02:30:32 AM

That would work physically, but would it work aerodynamically?

I'm not sure I know of a single aircraft where the prop discs are actually overlapping like that. Anyone know of one?

zenrat · July 24, 2024, 02:49:53 AM

Push-Pull nacelles...

Captain Canada · July 24, 2024, 05:26:34 AM

Looking forward to watching this one. Defo a neat aeroplane.

sandiego89 · July 24, 2024, 06:59:19 AM

Quote from: PR19_Kit on July 24, 2024, 02:30:32 AMThat would work physically, but would it work aerodynamically?

I'm not sure I know of a single aircraft where the prop discs are actually overlapping like that. Anyone know of one?

I can't think of side by side props overlapping. The Curtis Wright X-19 had fore/aft overlap and there were others with fore/aft nacelles or push-pull, but I imagine side by side overlap it cause tremendous vibration on the rear prop operating in the turbulent prop wash and reduced efficiency.

PR19_Kit · July 24, 2024, 08:09:08 AM

Quote from: zenrat on July 24, 2024, 02:49:53 AMPush-Pull nacelles...

Now THAT'S an idea Fred!

Like the Do-26, only with radials, and I'd only need the standard gull wing section then too, no need to worry about the strength of the vacform one.

All I need to do is lengthen the wings with the vacform bits.

That sounds like a winner to me, thanks VERY much.

PR19_Kit · July 24, 2024, 08:16:07 AM

The build's progressing slowly, holidays have lots of other attractions of course, and the cockpit's all been assembled now.

There's LOTS of bits, 27 in all, and some are very fiddly to get into place, and...................

.......as you can see from the above pic most of it will be invisible once it's assembled inside the fuselage!

The red arrowed gap is the size of the canopy and only the Captain's and Co-pilot's positions will be visible, with maybe just a hint of the radar ops consoles too. Such a waste, and I don't think I'll even bother to paint the rear half of the cockpit area.

The engine nacelles, which are also the weapons bays are nicely detailed, albeit sans any weapons at all. I may put a few bombs and depth charges in there later on.

Rick Lowe · July 24, 2024, 10:43:32 PM

Yep, Fred's idea is probably the best way to go.

Could you cut off the rear part of the interior and reuse it for some other build? Just a Thought...

McColm · July 25, 2024, 12:28:50 AM

That looks a lot better than the Mach2 model kit which I turned into a twin turbofan powered ASW with a few modifications.

PR19_Kit · July 25, 2024, 02:15:49 AM

Quote from: Rick Lowe on July 24, 2024, 10:43:32 PMCould you cut off the rear part of the interior and reuse it for some other build? Just a Thought...

I could do, yes, but I'll be lengthening the fuselage a bit in that area and I mat add a window or three.

PR19_Kit · July 25, 2024, 03:34:33 AM

Now here's a technical problem...................

With the push me/pull you layout, how will I cool the pusher engines as they're radials?

The cooling flaps on the kit can be modelled open or closed, all very nice, but they're BEHIND the engine and cowling. For the pusher engines that won't work as the 'cooling' flaps will be in FRONT of the rear engines.

It's difficult to find a pusher engined aircraft with a radial, and the B-35 and -36 don't count as their engines are buried in the wing and have complex cooling ducts etc. The only one I can find is the Northrop XP-56, and it doesn't seem to have any cooling ducts, but maybe there's an adjustable area slot around its contraprop?

Not only that, I'll either have to reverse the pitch of the rear props or invent a reverse rotation R-2600 engine. OK, I know I did that with the Merlins on the SM-77, but that'd have been relatively simple with a V-12, so is it just as easy with a 14 cylinder, twin row radial?

PR19_Kit · July 25, 2024, 04:50:18 AM

Ah, I think I've solved the prop rotation problem.

Having re-read my SM-77 thread, I didn't fit reverse rotation Merlins to it, they had an extra idler gear added to the prop gearbox, like the starboard engines on a Hornet. So I'm sure Wright could do the same job on the rear engines of the PB3M-1.

The cooling issue still remains though.