Academy 1/72 PBY-5A Catalina Engine Nacelle Details

[Sky Pilot]

I am currently "doing" an Academy PBY-5A Catalina and would like to add some detailing to the front cowling of the engine nacelles. The cowlings supplied in the kit are completely void of any detail i.e. panel lines and the flaps used for controlling the flow of cooling air around the engines. This is shown on the artwork on the front of the box but not on the kit plastic or the assembly instructions. I'm aware that Quickboost do an aftermarket set for this problem but it seems, from a number of reports, that it is NBG. So that is ruled out. As I've not been able to find any alternative sets I'm hoping that someone on here might help me with relevant details, drawings, pictures and links, particularly those related to the cooling flaps.

Any help will greatly appreciated.

[Admiral Puff]

Your most major problem is that the nacelles themselves are undersized - their outside diameter is about what the interior should be. The Quickboost set replicates this error, which is why it's NBG. If you can find one, the old Revell kit's nacelles are pretty close to the right size. You can use them as they come, or get rid of the engine detail and fit something like Vector R-1830s if you want seriously well-detailed engines.

Following on from this, the engine mounts on the wings really need building up as well to go with the resized nacelles. Alternatively, you can nick the Revell ones.

You may also be able to use the engines from the Airfix kit, but it's been quite a while since I looked at one and I don't remember how close to the right size they are.

[Work In Progress]

Admiral Puff is right about the size problem, but to answer the actual question...

Pics too big to post directly but open the links in new tabs

http://www.wingsovereurope.com/ww%202%20bombers%20gallery_2/Catalina..Walkaround...Sanicole%202005%20%2818%29.jpg

http://www.flevoaviationhobby.net/walkaround/aircraft/pby5a_phpby/1024/0009.jpg

http://www.flevoaviationhobby.net/walkaround/aircraft/pby5a_phpby/1024/0002.jpg

https://pauljwillett.files.wordpress.com/2013/06/img_7532_small_pby-5a_catalina.jpg

[JWM]

You may use aftermarket parts but still you may used undersized cowlings if you know how to enlarge them. Basicly there are two schools: first is to wrap thin plastic card around cowling up to desired diameter and use putty and sanding to made it smooth and enlarge the central opening diameter - but in case of Catalina, due to inlet of air at top it is more difficult. The second one is to cut it let say once in bottom, or twice or three or even four times and add some distance. More time you cut butter approximation to circle is obtained. Since PI=3.1415926539... - so roughly speeking 3, if the diameter should be enlarged for 2 mm you need to add a bit more than 6 mm as sum of all distances (+width of all cuts).. BTW - Airfix's cowling diameter is OK . I am going to do this soon using Academy cowlings for LIberator Mk I...

Best regards

J-W

[Don McIntyre]

I may be confused here, but weren't the earlier (PBY-1/-2 and possibly -3) cowlings a smaller diameter than those used on the -5s? Most of the pics used as illustrations in this thread are later models than we're discussing.

[occa]

Your most major problem is that the nacelles themselves are undersized - their outside diameter is about what the interior should be. The Quickboost set replicates this error, which is why it's NBG. If you can find one, the old Revell kit's nacelles are pretty close to the right size. You can use them as they come, or get rid of the engine detail and fit something like Vector R-1830s if you want seriously well-detailed engines.

Following on from this, the engine mounts on the wings really need building up as well to go with the resized nacelles. Alternatively, you can nick the Revell ones.

You may also be able to use the engines from the Airfix kit, but it's been quite a while since I looked at one and I don't remember how close to the right size they are.

I so hate it when they make improvement sets that are still wrong

[JWM]

I think very early Catalina had different cowling - here are some drawings, which show the difference

http://static.rcgroups.net/forums/attachments/1/2/6/5/7/6/a2165497-115-2a-jpg.jpg

http://static.rcgroups.net/forums/attachments/1/2/6/5/7/6/a2165496-99-1a-jpg.jpg

Regards

J-W

[Sky Pilot]

Firstly may I offer my sincere thanks to all who have responded to my question.

It would seem that I have opened yet another COW.

After considering the suggested alternatives I think I shall stick with the original Academy cowlings and improve their appearance by scribing in some suitable details.

WIP

I noticed from the pictures on the links that you provided, the two propeller types fitted to the BPY-5s. Can you or anyone else tell me what were the reasons for the differences and to which a/c versions were they fitted.

I shall complete my current Catalina build - I've yet to put an incomplete build to one side.

I would have considered doing a 1/48 Catalina but I just don't have the space to keep it

Once again many thanks.

[perdu]

The Airfix cowlings are right-ish but I had to make all sorts of changes to mine to get it remotely like the real things, notwithstanding the Airfix artist thinking he was drawing Bristol Hercules type cowlings with great big copper collector rings

Here's where I was fitting out the renewed cowlings to suit a pair of Aeroclub Twin Wasps before smoothing and adding filler

It all needed thinning out drastically to fit the white metal engines, and one of the engines needed repairing after having its front detailing cut away by someone in the postal service who must have thought someone was daft enough to post me a diamond ring in letter post

The offender hacked the envelope open with a mucky thumb nail and found it was only a semi-precious P&W not a diamond so it got delivered

Anyway new rear cowling rings attached awaiting filler and gills etching in, lots of tidying up due

This looks as if a completely new after market cowling and engine assembly is needed

[LDSModeller]

The whole of the PBY Catalina series 1 through 5A were powered by the PW R1830 of various designations

PBY-1 powered by R 1830-64 (900hp) - Cowling is different to PBY5A - no Airscoop under upper lip

http://albumwar2.com/wp-content/uploads/2013/05/39381-728x373.jpg

PBY-5/5A powered by PW R 1830-92 (1200hp)

(From Wikipedia) Note the heat exchange manifolds on the cowlings of this so probably a PB2B1/2

https://upload.wikimedia.org/wikipedia/commons/c/cc/PBY_5A_Catalina.jpg

How to fix the Academy Cowlings? I could suggest finding some DC3/C47 cowlings from say an Academy kit and try those (I don't know if the circumference would be correct though).

Failing that using the Academy parts and vacuufrom some new cowlings which probably would be about the right size. Problem is will the firewall and associated wing fairing require some surgery to adapt the new cowling?

Regards

Alan

[Admiral Puff]

I've thought about using DC-3/C-47 cowls, but there's a major difference between them and the ones on the Catalina. The Douglas aircraft was originally designed for the Wright Cyclone, a single-row, nine cylinder engine of greater diameter than the P&W Twin Wasp. When the decision was made to offer the Twin Wasp as an option, Douglas catered for the difference in diameter by leaving the firewall the same size as for the Cyclone and tapering the cowl towards the front. This meant that the sides of the cowls were not parallel. It's slight, but noticeable; the new Airfix C-47 shows it quite well. The Catalina, as Alan points out, was designed from the outset for the Twin Wasp, so that this problem didn't arise and its cowls were parallel sided. There are other matters to address, such as the repositioned oil coolers and different carburettor air intakes on top of the cowl, but these are minor in comparison.

Another option might be to use DC-4/C-54 cowls, but I haven't run the calipers over the Revell bits yet, and can't say how close they might come.

[paul178]

Get hold of a copy of this months Flypast they have done a multi page article on this aircraft.

[sroubos]

I built Academy's Catalina about a year ago and I agree the detailing is quite soft on them. I rescribed it and used them in the end, as the QB cowlings I got to replace them are indeed undersized. I did NOT find the kit parts to be undersized though - maybe they are but their diameter at least matches the nacelles they are supposed to fit onto, whereas the QB cowlings are about 1,5mm too small and therefore utterly USELESS.

Edited October 4, 2015 by sroubos

[racer53]

Just a thought, the B-24 and PBY both use P&W 1830's in real life, and their cowling is very similar. Intake is almost identical, oil cooler location is about right. Even the way the cowling slides up for access to the engine. Here is couple pictures from google that show my point.

It might be easier to find detailed B-24 cowling and make work, rather than scratch building cowls yourself...

[Admiral Puff]

Just a thought, the B-24 and PBY both use P&W 1830's in real life, and their cowling is very similar. Intake is almost identical, oil cooler location is about right. Even the way the cowling slides up for access to the engine. Here is couple pictures from google that show my point.

It might be easier to find detailed B-24 cowling and make work, rather than scratch building cowls yourself...

You're right, but AFAIK there are no B-24 kits out there, in ANY scale, that don't have the cheek oil coolers, other than the Magna resin for the LB-30 conversion. That's an expensive way to get a pair of cowls ... The case for a decent set of resin engines is getting stronger by the minute!

[racer53]

You're right, but AFAIK there are no B-24 kits out there, in ANY scale, that don't have the cheek oil coolers, other than the Magna resin for the LB-30 conversion. That's an expensive way to get a pair of cowls ... The case for a decent set of resin engines is getting stronger by the minute!

Next time i'll do a little more research. Sorry about that...

[Wm Blecky]

I just came across this post and after reading it, was wondering if one could use the cowlings from a B-17 kit to address the under size diameter of the ones on the Academy kit?  I know that it would not address the nacelles on the wings - perhaps laminating plastic card over them for that?

[top turret toddler]

Made me buy those aftermarket Catalina cowlings they did.....those evil resin casters (QB)  I agree fully with

otto that this is a very suggestive and immoral business model by "aftermarket" manufacturers for modellers

who take these things seriously enough to buy these resin sets. However basic or economic they are supposed 

to be. Perhaps imposing an embargo retaliation on Cz. would be in order ?! Argh..

Edited December 25, 2016 by top turret toddler

[Steve N]

 

The B-24 pic above is of course the venerable LB-30/B-24A AM927, which was actually refitted with off-the-shelf PBY engines and nacelles late in the war.  The aircraft is actually a bit of a mongrel.  She was used as a company transport by Consolidated, and subjected to all kinds of modifications over the course of her career, including a longer nose (from an RY-3, transport version of the Privateer) as well as the late "knife edge" windscreen introduced on the B-24M near the very end of the Liberator production run.

 

SN

[Steve N]

18 hours ago, Wm Blecky said:

I just came across this post and after reading it, was wondering if one could use the cowlings from a B-17 kit to address the under size diameter of the ones on the Academy kit?  I know that it would not address the nacelles on the wings - perhaps laminating plastic card over them for that?

 

B-17 cowls would be much too large in diameter, and too short in length.  The B-17 used the single-row R-1820, which had a larger diameter than the twin-row R-1830 used on the PBY.

 

SN

[72modeler]

On ‎10‎/‎3‎/‎2015 at 6:37 PM, Admiral Puff said:

I've thought about using DC-3/C-47 cowls, but there's a major difference between them and the ones on the Catalina. The Douglas aircraft was originally designed for the Wright Cyclone, a single-row, nine cylinder engine of greater diameter than the P&W Twin Wasp. When the decision was made to offer the Twin Wasp as an option, Douglas catered for the difference in diameter by leaving the firewall the same size as for the Cyclone and tapering the cowl towards the front. This meant that the sides of the cowls were not parallel. It's slight, but noticeable; the new Airfix C-47 shows it quite well. The Catalina, as Alan points out, was designed from the outset for the Twin Wasp, so that this problem didn't arise and its cowls were parallel sided. There are other matters to address, such as the repositioned oil coolers and different carburettor air intakes on top of the cowl, but these are minor in comparison.

Another option might be to use DC-4/C-54 cowls, but I haven't run the calipers over the Revell bits yet, and can't say how close they might come.

The C-54/DC-4, IIRC, used R-2000 engines, not 1830's so the cowlings might not be the same size or diameter- my Revell C-54 is up in the attic, so not close to hand to compare their diameters with the Revell Catalina cowlings.

 

Mike

[Work In Progress]

When P&W turned the R-1830 into the R-2000, they did so by enlarging the bore rather than the stroke (which is 5.5 inches for both engines). So the core of the engine is very similar. Sadly however the C-54 cowling has a pronounced taper which would make it look very wrong for a PBY.

[Wm Blecky]

On 10/3/2015 at 6:37 PM, Admiral Puff said:

I've thought about using DC-3/C-47 cowls, but there's a major difference between them and the ones on the Catalina. The Douglas aircraft was originally designed for the Wright Cyclone, a single-row, nine cylinder engine of greater diameter than the P&W Twin Wasp. When the decision was made to offer the Twin Wasp as an option, Douglas catered for the difference in diameter by leaving the firewall the same size as for the Cyclone and tapering the cowl towards the front. This meant that the sides of the cowls were not parallel. It's slight, but noticeable; the new Airfix C-47 shows it quite well. The Catalina, as Alan points out, was designed from the outset for the Twin Wasp, so that this problem didn't arise and its cowls were parallel sided. There are other matters to address, such as the repositioned oil coolers and different carburettor air intakes on top of the cowl, but these are minor in comparison.

Another option might be to use DC-4/C-54 cowls, but I haven't run the calipers over the Revell bits yet, and can't say how close they might come.

It would seem that my idea of the B-17 cowls is not a good one.  So speaking of DC-3 cowlings, although in real life they may not be suitable, but the model kit world does not always mimic real life with 100% accuracy.  With that in mind, what about the cowlings from the Italeri or even the ESCI DC-3 kit?

 

I looked at my Italeri kit's cowlings and don't think they looked quite right for this project.  I have yet to pull out my ESCI kit, so if anyone has one handy to compare...

[72modeler]

WIP,

 

Thanks for the info- was not aware that the R-2000 was a bored-out R-1830; will keep that bit filed away for future use! I pulled some kits and parts from my stash a while ago and did some measuring regarding PBY cowls. Here is what I found for diameters:

17mm  Academy PBY cowls

17mm  DB/Airwaves Twin Wasp resin cowls

17mm  Quickboost PBY resin cowls

18mm  Revell PBY cowls (not much bigger than the ones above, I know, but you can sure tell the difference!)

19mm  Hasegawa F4U-1/2 cowls

20mm  Italeri C-47A cowls

 

I do not  have any 1/72 scale drawings of the Catalina, so I can't comment on what the actual diameter is; hopefully somebody out there can help us all in that regard. The QB cowls appear to be just cleaner copies of the Academy parts- wish I had known then that they and the Academy parts were undersized! The only reason I included the Hasegawa Corsair cowls was because they are straight-walled, not tapered, and depending on what the actual diameter turns out to be they might be very close. You can remove the extra length either behind the cowl ring or in front of the cowl flaps, which would also need to be modified to duplicate the ones used on the  PBY. The kits are also pretty plentiful  out there and cheap, and they have a ton of  parts that can be used on other projects. The C-47A cowlings are not tapered, at least not in the issue that I have, but are too fat anyway and the cowl ring is too bulbous and rounded to resemble the one on the PBY. Hope this info will be helpful. Wish I had been a member of Britmodeller before I discovered it, as I'm just now finding out about the inaccuracies of some of the kits and aftermarket parts I have! 

 

Mike

 

This just in! Found this Catalina website and have attached a link- lots of useful bits and it does list the diameter and width of the standard and paddle-blade props! Merry Christmas from the Lone Star state!

 

http://pbycatalina.com/specifications/

Edited December 26, 2016 by 72modeler
corrected misspelled word; added link

[Work In Progress]

That's a useful list. Sadly my Revell PBY is at another location or I'd get started on it: I'm very fond of that kit.