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B-17 Engine question; Aftermarket parts
Topic Started: Oct 14 2016, 06:56 PM (475 Views)
Santacarl
Advanced Member
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Hi all,

I'm building a 1/72nd Revell B-17F/G....Memphis Belle.

I am adding some extra detail to the build with PE and resin engines...

Well....I got a set of Wright 1820 Cyclone engines from CMKKITS.... I also got as set from Quickboost.

Now.....the kit, of course, came with engines..... When I lay the 3 different manufacturer engines out side by side you would swear that they are different engines....Especially the center area where the prop shaft comes out....all 3 engines are different sizes in that spot.....

How is a person to know which one is closer to the original? Grrrrrrrr... This is enough to make you pull your hair out... Well....actually the cmkkit engines , once assembled, don't even fit in the engine cowling so that one is not an option.....

Anyone have any experience to share on this?

Thanks....SC
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Graham Boak
Hero
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Which engine looks most like the real thing? That's the one I'd choose. It may be that different versions of the R-1820 had different reduction gear housings, but I suspect that's not the reason for the difference in the model parts.

I also suspect that the CMK one is accurate to 1/72, which is why it won't fit in the cowling, with its overscale wall thickness. If you used a power tool to open up the cowling, would that help? The other thing you can do is to file off the top each cylinder valve gear, to reduce the overall diameter. If not too extreme, this won't show once the engines are in place inside the cowling.
Lancashire, UK
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Mark Schynert
Member Avatar
Yeast
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There are lots of R-1820 pix on the Net--look at a few dozen--you might find that more than one is a reasonably faithful rendition with regard to some photo.

Or not, and that will help sort it. But Graham's point is well-taken, because the 'right' Wright might not fit into the kit cowlings without surgery. Grinding off cylinder tops for a fully cowled radial is something I do with some frequency, since some cowlings are a scale 6" less in interior diameter than the real thing.
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Big Kohona
Hero
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Santacarl
Advanced Member
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Graham Boak,Oct 14 2016
09:31 PM
Which engine looks most like the real thing? That's the one I'd choose. It may be that different versions of the R-1820 had different reduction gear housings, but I suspect that's not the reason for the difference in the model parts.

I also suspect that the CMK one is accurate to 1/72, which is why it won't fit in the cowling, with its overscale wall thickness. If you used a power tool to open up the cowling, would that help? The other thing you can do is to file off the top each cylinder valve gear, to reduce the overall diameter. If not too extreme, this won't show once the engines are in place inside the cowling.

The CMK looks the most realistic.....BUT I would literally have to cut off the tops of the cylinder heads or grind the inside of the cowlings by a hair over 1/32" to make the difference go away...

Grinding the cowlings out would then impact their mating to the wing engine mount points....

The idea of grinding off the tops of the cylinder heads is pretty tedious (or at least in my mind it is....how to get them all equal height is what is throwing me a curve)....

Gonna have to give this some more thought...

Thanks for the ideas.....that helps.
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Santacarl
Advanced Member
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Big Kohona,Oct 15 2016
09:27 AM

Now, if you want really upper quality resin engines, look no further than Vector Resin engines.
This is their B-17G Wright Cyclone R-1820G Late engine:
Posted Image


Hmmm...those look nice. Looking at the picture on the left none of the others I have show that 'thing' between the 2 cylinder heads at the bottom of the picture..... I'm wondering if that is a variant of the engine for another aircraft other than the B-17.....

Nope....I went and looked up pictures of the restoration of the Memphis Belle....that strange 'thing' is clearly visible on the Belle's engines.....so it appears the Vector engines are the most accurate.....which also tells me they probably won't fit inside the cowlings either....the thickness of the cowl wall is likely out of scale to the real life AC..
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Steve N
Hero
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The "thing" is the oil sump. I built up a set of engines for a (still unfinished) B-17 a few years ago by modifying the engine from the Hasegawa SBD, then making resin copies and adding an ignition ring made from lead wire. They look the part to me, although in the long run it would probably be cheaper and certainly easier to buy the Vectors (although it appears you still need to add the pushrods and ignition ring.

Posted Image

Here's the final painted engine, next to the atrocious Academy engine it will replace.

Posted Image

I haven't looked that closely at the Revell engines, other than to note that the pushrods are much too thick. Frankly I found the kit to be so underwhelming in other respects I didn't pay a lot of attention to the engines.

SN
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dknights
Member Avatar
The court of LAST RESORT!
[ * ]
Vector engines are awesome. Just picked one up for the N1K2. Very nice. Got it from Sprue Brothers.
David M. Knights
Fortes fortuna adiuvat

14 Finished: Special Armor V-2, Airfix P-51
15 Finished: SBS Gladiator engine
16 Finished: Brengun C2 Wasserfall, Merit SS-N-2 Styx, World's smallest diorama, Airfix Hurricane.
17 Finished: Japanese Carrier Deck, Belcher SS-4, Italeri AB41, PLAN Type 039A (not 72nd scale)
18 Finished: NONE
The bench:Platz T-33, Trump. T-34/85, Meng F-106, Airfix P-51 #2, Airfix P-40
Revell MiG-21F-13, Ace Citroen V-11
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Santacarl
Advanced Member
[ *  *  * ]
Steve N,Oct 15 2016
08:48 PM
The "thing" is the oil sump. I built up a set of engines for a (still unfinished) B-17 a few years ago by modifying the engine from the Hasegawa SBD, then making resin copies and adding an ignition ring made from lead wire. They look the part to me, although in the long run it would probably be cheaper and certainly easier to buy the Vectors (although it appears you still need to add the pushrods and ignition ring.

Posted Image

Here's the final painted engine, next to the atrocious Academy engine it will replace.

Posted Image

I haven't looked that closely at the Revell engines, other than to note that the pushrods are much too thick. Frankly I found the kit to be so underwhelming in other respects I didn't pay a lot of attention to the engines.

SN

Steve...

Nice job on the engine build....it looks really good.... That's the look I'm after....as to the Revell engines....they just don't have the detail and some parts are 'clunky' looking....i.e. they're out of proportion in relation to the real engine...
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SkyKing
Advanced Member
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Mark Schynert,Oct 14 2016
09:37 PM
But Graham's point is well-taken, because the 'right' Wright might not fit into the kit cowlings without surgery. Grinding off cylinder tops for a fully cowled radial is something I do with some frequency, since some cowlings are a scale 6" less in interior diameter than the real thing.

You can also vac-form new cowlings, using a kit cowling as a master. If it's an integral engine/cowling, chuck it in a motor tool, spin it up, and use a sanding stick on the exterior to reduce the diameter a bit before vacforming so your new cowling has the correct external diameter. The vacformed part will be much nearer scale thickness and the resin engine should fit inside without any modifications.
Michael McMurtrey
IPMS-USA #1746
IPMS-Canada #1426
Carrollton, TX
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Santacarl
Advanced Member
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SkyKing,Oct 20 2016
09:37 PM
You can also vac-form new cowlings, using a kit cowling as a master. If it's an integral engine/cowling, chuck it in a motor tool, spin it up, and use a sanding stick on the exterior to reduce the diameter a bit before vacforming so your new cowling has the correct external diameter. The vacformed part will be much nearer scale thickness and the resin engine should fit inside without any modifications.

Wow Sky....that's waaaaay out of my league! LOL.... That's like telling Clark W. Griswold to put up Christmas lights! You know the outcome will be catastrophe.....haha...
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Big Kohona
Hero
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