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Clunkmeister

HB Models B-24 Hints, Tweaks, Tips

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If I may add an observation. The correct size engines will not fit into the cowlings without modifications. Since they are undersized and intakes slightly misshapen. I was talking about that to a friend of mine , he did some measuring on the kit and came to conclusion that we need something like, Vector did in 1/48 for Monogram kit.

Again I am not trying to be negative, or bash the kit, just presenting observation based on measurements .

 

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This is not an isolated thing...

The complexities of our hobby dictate that a cowling sized to scale will perforce require an engine (if provided) that is undersized... Even more so if the kit cowl itself is too small to begin with.

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3 to 5mm in diameter based on the different drawings. Not mentioning the shape. I came to the similar conclusion by comparing the scale down pictures with the pictures of the real thing. 

here you can see the vast difference in the cowling shape and size, Image is tilted and lined up to match the size of the opening. Not bang on, just to get the perception .

collage.thumb.png.d95ab2e1d9c30f85ca1f4e45ae952718.png

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10 hours ago, ScaleRC said:

Williams Brothers current product listing:

http://www.wmbros.com/store/c1/Featured_Products.html

The new WB appears to be a one-man operation, or a family one.

Whatever, they are a real pleasure to deal with, and react promptly to demands. Lastly, their new decals service is invaluable for people like me who have an old stash of old WB kits.

... And, btw, they have the 1/32 Wasp engine available for USD 5.95. Its not the double Wasp, but still a good and relatively cheap source of engine, even if you take two to make a Double-Wasp.

FWIW, the P&W cylinders were almost all the same in dimensions, or the difference is negligible in 1/32 (like 0.5 mm in diameter of the cylinder alone). Of course, the cylinders got more and more fins as they evolved, but we cannot reproduce that many fins in this scale anyway.

All of this to say that the big diameter difference between the different P&W radials is located in the area of the crankcase, and that is easy to scratchbuild.

Hubert

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13 hours ago, Martinnfb said:

3 to 5mm in diameter based on the different drawings. Not mentioning the shape. I came to the similar conclusion by comparing the scale down pictures with the pictures of the real thing. 

here you can see the vast difference in the cowling shape and size, Image is tilted and lined up to match the size of the opening. Not bang on, just to get the perception .

collage.thumb.png.d95ab2e1d9c30f85ca1f4e45ae952718.png

In this comparison are we assuming the diameter of the opening is correct on the model or is it oversized? If it is too big, that may give the illusion the outside is small?

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Hey all

The TSC4-G (R-1830-41)  was 4' 0.0625" Dia. X 5' 3.48" lg. It was turbocharged simaliar to the B-17 engines. All of P&W twin row engines were called twin wasps.

  So I  just measured the engine diameter of the kit engine and it scales out to 43.232" (1,098.092 8mm)  the actual P&W R-1830 should measure 48.0625'' (1,220.7875mm) which leaves a difference of 4.8350" (122 809mm) thats 2.4175" (61.4025mm) off in radius in 1/32 scale thats 1.92mm!

The Trumpeter F4F Wildcat P&W R-1830 scales out correctly its 48.0625" in dia. But the Trumpeter F4F P&W R-1830 will not fit in the cowling of the Hobbyboss B-24J.

 Williams brothers twin wasp engine will fit in the cowls of the HB B-24j.  I need to measure it to get the correct size but its pretty damn close to the kit engine diameter.

This is a TSC4-G R-1830-41

Pratt_&_Whitney_R-1830_Imperial_War_Museum.jpg

The one on the left is the kit engine and the one on the right is the kit cowl over the Williams brothers engine 20190112_151654.thumb.jpg.068741a3dff853c10ad5a8fbe5fc6542.jpgyou can see that the WB engine looks much closer to the real thing.

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1 hour ago, NigelR32 said:

In this comparison are we assuming the diameter of the opening is correct on the model or is it oversized? If it is too big, that may give the illusion the outside is small?

I used a wrong example slapped together hastily . Sorry. If you look at the picture below, you can see the shape of the cowling is flattened on sides and top and bottom are slightly thicker. Unfortunately I don't have the kit to get correct an angle shot.

b-24-engine-robert-wilder-jr.jpg.7be8ac76c9962dd7b226ed170d6fa8fa.jpg

1 hour ago, CrankyCrafstman said:

Hey all

The TSC4-G (R-1830-41)  was 4' 0.0625" Dia. X 5' 3.48" lg. It was turbocharged simaliar to the B-17 engines. All of P&W twin row engines were called twin wasps.

  So I  just measured the engine diameter of the kit engine and it scales out to 43.232" (1,098.092 8mm)  the actual P&W R-1830 should measure 48.0625'' (1,220.7875mm) which leaves a difference of 4.8350" (122 809mm) thats 2.4175" (61.4025mm) off in radius in 1/32 scale thats 1.92mm!

The Trumpeter F4F Wildcat P&W R-1830 scales out correctly its 48.0625" in dia. But the Trumpeter F4F P&W R-1830 will not fit in the cowling of the Hobbyboss B-24J.

 Williams brothers twin wasp engine will fit in the cowls of the HB B-24j.  I need to measure it to get the correct size but its pretty damn close to the kit engine diameter.

This is a TSC4-G R-1830-41

Pratt_&_Whitney_R-1830_Imperial_War_Museum.jpg

The one on the left is the kit engine and the one on the right is the kit cowl over the Williams brothers engine 20190112_151654.thumb.jpg.068741a3dff853c10ad5a8fbe5fc6542.jpgyou can see that the WB engine looks much closer to the real thing.

That would be great solution Ron.

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Hey Martin 

 If you look at the real engine picture and the model photo you can see that I showed the model upside down...whoops sorry about that.

Ron G 

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Thank You Ron. Silly question I have to ask, but did trumpeter differentiate the shape of the cowling in relation top/bottom?  Again I don't have the kit, just seems that they didn't . Not sure.

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All good info guys ! Carry on.....

Harv

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4 hours ago, CrankyCrafstman said:

Hey all

The TSC4-G (R-1830-41)  was 4' 0.0625" Dia. X 5' 3.48" lg. It was turbocharged simaliar to the B-17 engines. All of P&W twin row engines were called twin wasps.

  So I  just measured the engine diameter of the kit engine and it scales out to 43.232" (1,098.092 8mm)  the actual P&W R-1830 should measure 48.0625'' (1,220.7875mm) which leaves a difference of 4.8350" (122 809mm) thats 2.4175" (61.4025mm) off in radius in 1/32 scale thats 1.92mm!

The Trumpeter F4F Wildcat P&W R-1830 scales out correctly its 48.0625" in dia. But the Trumpeter F4F P&W R-1830 will not fit in the cowling of the Hobbyboss B-24J.

 Williams brothers twin wasp engine will fit in the cowls of the HB B-24j.  I need to measure it to get the correct size but its pretty damn close to the kit engine diameter.

This is a TSC4-G R-1830-41

 

 

In my opinion this will always be the case with injection moulded kits Ron. In reality the cowling around the engine would have been, say, 1.2mm max thickness sheet material. It would have fitted very tightly around the engine, so, if the kit engine were correct diameter and the cowling was correct, the plastic would need to be 1 1/2 thou thick in 1/32 scale. (Which begs the question... is the cowling on the F4-F too big outside)?

Anyway, we now know that the kit engine is simple and too small and the cowling is mishapen. Great!! Good news all round then!!

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Hey Nige 

  I don't think the cowl on the f4f fit that tight,  but I may be wrong. The problem with the HB B-24 is the thickness of the plastic it's nearly 1.5mm thick! Which is full size 50.8mm or 2", plus it's not the correct shape.

  I know I'm using the WB engines I have and doing a little scratch building to detail them out. Better push rod tubes, adding the propeller pitch regulator and a better ignition ring with lead detail wiring.

Ron G 

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Just playing with plastic parts guys.. I can't do any modelling as I cut my thumb big time and can't hold a knife accurately.

Looking at pics on Google, I think i have found another issue concerning the engines that could be fooling us.. the engines are too far forward on the kit, the front face of the front cylinders appears to sit just behind the cowling? So... we can fit a correct sized engine with the correct sized gearbox on the nose, it just needs to go further back. 

Now, remind me, what should the magnetos look like on the B-24?

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Forgive me, but I'm struggling a little with something here...

Are the EXACT dimensions of the B-24 cowlings not a known fact?

I can tell you the dimensions of the Fw190 cowling, exactly where the motor is placed, how it compares to the various BMW 801-powered bomber variants, and therefore how accurate the various 1/32nd scale kits are when compared to the actual thing. And this from a Regime bombed into submission with most of it's documents thrown into the fire.

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1 hour ago, NigelR32 said:

Just playing with plastic parts guys.. I can't do any modelling as I cut my thumb big time and can't hold a knife accurately.

Looking at pics on Google, I think i have found another issue concerning the engines that could be fooling us.. the engines are too far forward on the kit, the front face of the front cylinders appears to sit just behind the cowling? So... we can fit a correct sized engine with the correct sized gearbox on the nose, it just needs to go further back. 

Now, remind me, what should the magnetos look like on the B-24?

Hey Nige 

 They may be to far forward, but the correct P&W R-1830-41 will still not fit inside of the HB B-24J's cowls, no matter how far back you move them. I have a R-1830 from Trumpeters F4F-3, which is the correct diameter (see previous post) and it WON'T FIT!  The R-1830-41's have the magnetos mounted on the rear, similar to the Japanese Sakae engine in Tamiyas Zeros. They should be similar the Sakae is a copy of the P&W R-1830. If you look closely at pictures of the R-1830 you will see two wire conduits coming off of the ignition ring, one on each side. These are the feeds form the spark plugs back to the magnetos on the rear of the engine. Hope this helps clear this up. In the photo below you can see the port side feed on the right of the photo. Its roughly 3 to 4 times as big around as the plug leeds. The black and silver thing on the top of the gear case is the prop pitch regulator.

20190105_141111.jpg

Ron G 

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Here are some more pictures of R-1830 series engines.

This one is like the type used in the B-24'sR1830 Twin Wasp 2.jpg

This one is the type used in the F4F-3/4/5 and is what comes in the Trumpeter F4F kits.09PrattWhitneyR1830.jpg

This a rear view of an R-1830 with the carburetor on top. Not sure what plane this is.R1830 Twin Wasp 3.jpg

These are rear views of what I believe are      R-1830s from B-24s and you can see the magnetos. They have the carburetor on the bottom, not sure if the B-24s had this set up5854675744_1f4ae2653f_b.jpg

pratt-whitney-r-1830-twin-wasp-radial-10632604.jpg

Ron G 

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These showed up yesterday. Nicer than I expected, but these are the first time I have ever used Airscale, but highly impressed.

108B1A2B-A7F8-410C-B668-E5E254101072.jpeg

AC04D7B9-4135-4BCA-84EA-5B3FB8CF8066.jpeg

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I wish he would do a B 17 set.....harv

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Yeah, but Preters is definitely  better....harv

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