Quote from: DogfighterZen on February 07, 2025, 06:35:01 AMand both the US and UK were not keen on having one land or crash on Japanese soil and allowing them to get their hands on the tech.

Yup, that was one of the reasons the RAF didn't post any Meteors to Europe until the War was very nearly over.

Am I correct in recalling that the P-51D's Merlin cowling was more or less (if not actually) big enough to take a Griffon without modifications?

The race P-51s that used Griffons just extended them a tad IIRC. The outer shape looks pretty much the same as a Merlin powered one.

Not sure if it is an optical illusion but the nose of a Merlin Spitfire seems to have a pretty flat top, while a Griffon Spitfire seems to curve down towards the Spinner.

The whole engine of a Griffon Spitfire is canted down quite a bit, you can tell by looking of the downthrust angle of the prop.

Quote from: kitbasher on February 10, 2025, 05:48:25 AMAm I correct in recalling that the P-51D's Merlin cowling was more or less (if not actually) big enough to take a Griffon without modifications?

Quote from: PR19_Kit on February 10, 2025, 07:52:11 AMThe race P-51s that used Griffons just extended them a tad IIRC. The outer shape looks pretty much the same as a Merlin powered one.

Gents, i'm sorry but no, it wasn't. The Griffon has a 6% larger frontal area. and they had to do quite a lot of structural mods to fit the Griffon in there.
I believe it's easy to see in the pics, you can see the bulges over the "heads". Also, compare the height and shape of the fuselage from the exhaust stacks to the curve at the top of the cowling. It's definitely wider.

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I've read a bit about this conversion, besides watching quite a few interviews/docs of the teams who did it for the racers, they all say there's not enough room for a Griffon in the normal P-51 cowling so, there's that.
BTW, i have to thank you for bringing this up as the racer's image has made me decide on the exhausts... I was gonna leave this mod for another build but now i see it's something i'll regret not doing... i'll have some surgery to do but i think it'll be a nice detail.

Regarding the model, i've had to replace a resin part which, doesn't make any sense to me. It's the tail gear support structure, made of very thin(~1mm)resin, cast horizontally... It snapped as soon as the blade got under.
Still, i see similar small parts on the sprues, why not styrene instead of resin?
Simple fix, though. You can see the resin block on which the parts came on the top right and to the left  you can see the fragments just recreating the part to check the size for a new one. Out comes the small bits and scrap styrene bag...

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A few minutes laterrr...
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Crude, yes, it's gonna be closed inside the fuselage and never seen again, so it's more than good enough.
So now, guess it'll take a bit longer as i'm gonna remove the Merlin's exhausts and put the Griffon's in.

 

Thanks for clarifying 👍

The problem is that very few pics are ever taken of an aircraft head-on.

As for resin landing gear, most of them would be candidates for the 'Bad Idea GB'! 

Resin is just too fragile, specially when they're built to 'true scale', as many of them purport to be.

Quote from: kitbasher on February 10, 2025, 11:47:14 PMThanks for clarifying 👍

My pleasure, mate!  
And i'm home on sick leave for the rest of the week so this helps to keep me entertained while coughing my throat out or draining my nose...  
This type of discussion is something i enjoy. I always end up either reading an article i haven't read before or finding pics i hadn't seen so it's always an opportunity to learn. 
One thing i'm almost sure will happen when i do post the finished build on Facebook groups is that there will be people saying stuff like "Oh. it's too heavy, it's too bulky, it's little improvement over the Merlin, etc, so it would never happen! " 
Sure, i'm also of the opinion that back during the war, as it happened, there was little to gain from putting Griffon-powered P-51s in production. They were doing fine with the Merlin and all the hassle to produce what would almost be a completely new fighter(like the P-51H) would take too long and wouldn't help the war effort in any significant way. And i've read that Edgar Schmued, the designer, wanted to keep the Merlins in the Mustang so,
But still, if the engine didn't really show any substantial advantage compared to Merlins, why did the Brits insist and kept the Griffon on the Spitfire all the way to the Spiteful/SeaFang? I believe that says something about the engine.
So, that's where i turn to the British, who apparently had 1000 of the H on order but cancelled it around the end of the war. They created the original Mk.X Mustang prototype so it makes sense to me that they'd be the ones doing it with the Griffon to create the Mk.XX.
Funny fact is that the Griffon might have solved the instability issues caused by the rear fuselage gas tank
on the Mustangs that made it tail heavy until the tank was almost empty but, obviously, it would also move the CG forward as it used up the gas in that rear tank...
Racing Mustangs with the Griffon were built from P-51D so, the original fuselage. On most of the racers you see the H tail fin and they seem to fly well, at least well enough for races.
And that's probably what it would take, the extended fuselage and bigger tail of the P-51H to further mitigate the Griffon's installation issues and, my idea for the build is that's what the folks at Rolls Royce thought as they decided to do it.
Instead of cancelling the 1000 airframes, the RAF would reduce the number to about 150, same number as the Spiteful order. The counter rotating props would deal with the engine's torque, i suppose.
Because this is a rather complicated subject, with this build i'm keeping the backstory simple, just creating a background where it was put into service for a brief period. This will be the prototype and maybe i'll only expand a bit more on the test period. 

Quote from: PR19_Kit on February 11, 2025, 01:38:08 AMThe problem is that very few pics are ever taken of an aircraft head-on.

As for resin landing gear, most of them would be candidates for the 'Bad Idea GB'! 

Resin is just too fragile, specially when they're built to 'true scale', as many of them purport to be.

I think you can find a decent amount of pics of several jets although i admit that warbirds are harder to find from a head-on view.
In this case, there are plenty of close up pics of the Griffon Mustangs, especially of the cowling. Yes, it is even taller because of that intake on top but it's easy to see the wider section right above the exhausts.

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I understand why someone would say they're the same but clearly, these cowlings are all exclusively built for these racers so it would only make sense to make a cowling properly adjusted to reduce drag.
On my P-51H, i'll just say Roll Royce took the easy way and simply added the same bulges used on Spitfires to reduce development and production time.
Regarding resin, i agree. I'm not the biggest fan of resin parts but, when the alternative is spending countless hours making my own parts, which would probably never have the resin bits' quality, i'll make the effort and dig out the CA tube.
Those bits which i destroyed didn't make much sense as there were similar sized bits on the sprues and the way that they're molded, one side of the triangle was attached to the casting block, making it very difficult to cut off without damaging it.

After this long post, all i have to say is, although i feel like Cr**p, i may get some work done during these next days.

 

Get well soon, matey.  Therapeutic modelling will do you good.

And thanks again for the Mustang/Griffon detail, although    you've made me want to throw a Griffon Mustang together!

Quote from: kitbasher on February 11, 2025, 07:07:30 AMGet well soon, matey.  Therapeutic modelling will do you good.

Thank you! I'll try my best to have something to show before i get back to work.

Quote from: kitbasher on February 11, 2025, 07:07:30 AMAnd thanks again for the Mustang/Griffon detail, although    you've made me want to throw a Griffon Mustang together!

I think you should follow your heart's wishes! 

There's some Griffon Mustang profiles and 6-views at http://taichi56jp.g1.xrea.com/ Just small ones to view for free.
At least Red Baron, Precious Metal and Miss Ashley II (which wasn't really a Mustang but the fuselage was based on the Mustang construction).

Oh... He has been posting many larger profiles on facebook https://www.facebook.com/groups/13949458301

Browsing his posts ( https://www.facebook.com/groups/13949458301/user/1261719831/ ), Precious Metal looks much shorter then Miss Ashley II, and Red Baron seems to have a much straighter nose.

Quote from: perttime on February 11, 2025, 10:20:38 AMThere's some Griffon Mustang profiles and 6-views at http://taichi56jp.g1.xrea.com/ Just small ones to view for free.
At least Red Baron, Precious Metal and Miss Ashley II (which wasn't really a Mustang but the fuselage was based on the Mustang construction).

Oh... He has been posting many larger profiles on facebook https://www.facebook.com/groups/13949458301

Browsing his posts ( https://www.facebook.com/groups/13949458301/user/1261719831/ ), Precious Metal looks much shorter then Miss Ashley II, and Red Baron seems to have a much straighter nose.

Precious Metal was a normal P-51D lengthwise, with only the tail fin of the H, as was Miss Ashley, which had the H's complete tail so, they may have extended the rear fuselage before the tail was grafted on.
The Red Baron's cowling has an intake on top, similar to the one on Precious Metal but it's much wider and that's probably what makes the cowling look so straight.
I find it hard to judge their length on those profiles, especially with those smaller canopies.

News for the build, i've managed to extract the Merlin's exhaust pipes without damaging the surrounding detail so now its time to drill...

Back to the build, issue with the exhausts out of the way.
Yesterday i cut the Merlin engine's exhausts off so today i got my mini-drill out and after some pencil lines to mark the exact spots, i carved and drilled out the opening for the Xtrakit Spitfire Mk.22's exhausts.
Did it slowly, checking multiple times with the exhausts and the Griffon's cowling bulges in place to make sure i was drilling where i was supposed to...

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After both openings were done, some styrene strips were added on the interior of the fuselage to make a base for the exhausts. This way they can be painted separately and added later after all the paint work has been done of the fuselage.

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Now it's the easy but boring task of cleaning up the molding lines and use a drill to carve up the interior of the Xtrakit exhaust pipes.

 

Nice work ! Love the Mustang. Then again, who doesn't !