P-51B dorsal fin

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Me too...just for fun.

'The Brits had the money, the engine but, they could make no Mustang'

We didn't need too...we had our wonderful Spitfire.
The PR version could fly to Berlin and back.

John
 
Readie said:
Me too...just for fun.

'The Brits had the money, the engine but, they could make no Mustang'

We didn't need too...we had our wonderful Spitfire.
The PR version could fly to Berlin and back.

John
Click to expand...

Ah, was that to take photos of German fighters shooting down American bombers?
 
Sorry to continue digressing from the original topic of this thread, but Greg, I have to continue to disagree re the Typhoon canopy.
It is a common misnomer that the Typhoon canopy was used on the P51D/K and the P47, an error which has probably grown up from statements such as "We liked the idea of the all round vision canopy, so used the Typhoon canopy on the... " for example.
What in fact is meant here is that, the concept was used, and a similar style of canopy designed and fitted to both the above aircraft.
The glazed section on the standard 'bubble' canopy fitted to the Typhoon, Tempest and Sea Fury is approximately 48 inches in length, not including the lower frame and, overall, it is a relatively small, low-profile canopy.
The glazed section on the Inglewood - built P51D canopy is approximately 72 inches long, with the profile, although very similar, being different, higher and elongated, and the cross section a different, more compound - curved shape at the forward frame. The Dallas - built P51D and K differed again, with a different, more pronounced, rear profile, whilst the TF-51D, and some other twin-seat P51s, had an even longer, higher canopy.
(Some confusion may arise with the Sea Fury, as there are at least two currently airworthy examples displaying a longer, non-standard canopy, normally associated with a two-seat conversion.)
The attached scale drawings should clarify things, albeit they are rather feint. Typhoon top, Inglewood-built canopy centre, Dallas bottom.
 

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I agree with Terry.The difference is noticed very clearly. Of course the conception of the drop-shaped conopy might have been picked up and adjusted by the US designers. But it is still the English idea. Am I right?
 
Yes my friend. However, there is a possibility that an original Typhoon canopy glazing was fitted to a custom - made frame, and fitted to a cut-down P47 at Burtonwood, UK, as an experiment.
I would have to find the info to confirm, but whatever, the production P47 'bubble' canopy was different again compared to the Mustang and Typhoon.
 
Airframes, you can believe what you want in good health and with good wishes. I did not claim the entire P-51D / K line used Typhoon canopies. What I said was the first two (or several) bubble canopy versions of the P-51D were built with Typhoon canopies. I have seen the documentation of same, and I believe it. If you don't, so be it.

What came later was probably North American's idea of how to proceed. The fact is they did use Typhoon canopies to study the concept. Whatever cvame later was what was required to meet the Mustang front canopy line with a blown canopy instead of using alimunin to make the Typhoon canopy strealimed enough when it was used a a "test vehicle."
 
The introduction of the tail fin fillets is also associated with the introduction of the tail 66 gallon tail tank, which made the P-51 very difficult to fly and eventually
forced missions starting with partially filled tail tanks; the fillet helped stabillity.

The P-51 had some minor stabillity issues: it could under no circumstances be snap rolled; some aircraft were lost in attempting this manouver. These handling issues were resolved in the P-51H which among other modifications incorporated a longer tail to increase the tail momment arm. These improved the handling so much the aircraft was now considered to have good enough handling for carrier use however the war ended before any serious full scale carrier builds could be made.

The Merlin would have been unneccesary for the P-51B The two stage Allison V-1710-121 was available at this time and could have provided equal performance; it may even have been easier to produce as the two stage V-1710-121 did not use bulky intercoolers (used water injection when needed) and could have been introduced with less airframe mods.

The idea for the bubble canopy seems to have been around for a long time think of the japanese fighters and P-39, also note that had the Luftwaffe chosen the He 112 over the Me 109 a bubble canopy would have been standard on the Luftwaffe's principal fighter: the FW 190A being likely the earliest mass implementation of blown canopy as opposed to a glass house type: it certainly inspired the allies to get their own skates on in this area.

Some pilots reported slighty rougher handling at mach limit due to the bubble canopy and they occaisionally lost diving competitions with late model Me 109 which by then had the new tall tail rudder with the horn balance replaced (which caused high speed dive problems). There would only be a fraction of a tenth of a mach in this.
 
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Though I believe the 2-stage Allison would not have been a bad choice (a bit prejudiced there perhaps), the Merlin wasn't a bad choice. As it turned out, the Merlin-powered Mustang was a great plane indeed, worthy of mass-production if ever a plane was.

The bubble canoopy never was a lower-drag installation, but it DID give a lot better visibility. In a diving attack, I doubt if the difference between a bubble canopy and the turtledeck type was a big enough difference to change the outcome of the fight. But I could be wrong if the apparent loser started his dive high enough ... maybe he COULD escape. I suppose we'd have to ask a combat veteran who had flown both types of canopy enough to know. I'll try that next ime we get some veterans at the museum. It doesn't mean the veterans who show up would know, of course, but I can ask.
 
Greg - Lednicer did a nice paper on studying the P-51B/D, Spit 9 and Fw 190D to examine the pressure distributions. While the design may or may not have considered the aerodynamics of the windscreen canopy, the D was designed with a lower angle than the B.

The P-51D canopy was superior aerodynamically to the P-51B (marginally), about the same as the Fw 190D and much better than the Spit 9.

The key distinction was a stagnation pressure build up at the base of the P-51B and Spit 9 windscreen. Apparently when the angle on the windscreen on the D canopy was reduced by 5 (? have to check and I'm consumed by indifference at the moment) degrees, it was enough to eliminate the problem.
 

So back to the question. Why use a Typhoon canopy at all? Sitting in a Typhoon would give a designer and a pilot all the info they needed tod determine the value over a birdcage or even Malcolm Hood. The production versions had the same radio installation as the first prototype (43-12102), and that bird is the one most often shown flown by Chilton over the Santa Monica Mountains.

I'm willing to be convinced otherwise - but it doesn't make a lot of sense to 'try' a configuration that required airframe mods once, then switch to a new design tailored for the airframe and re-modify the airframe to take the production version. The source for Typhoon canopies was in the UK. Tooling to build under license would take as much or more time than for a local US manufacturer. So, what documentation are you pointing to?

Regards,

Bill
 
Greg, apologies if you think I disbelieve you - I don't.
I was not aware that the first two P51D airframes had used an actual Typhoon canopy as a pattern/trials etc.
I have only seen one pic of the first prototype, converted from a 'C' model I believe, which appears to have a standard 'D' type bubble.
It was/is only my intention to dispel the myth that Typhoon canopies were used in production.
Regards,
Terry.
EDIT: Sorry. Didn't see your post Bill. It's interesting that the only (almost) complete Typhoon in existence today, in the RAF Museum, Hendon, UK, only survived as it had been 'loaned' to the US for study and evaluation purposes. It was returned to the UK, in exchange for a Hurricane, in the late 1960s, with some parts missing.
It's possible that this was the airframe which influenced the P51D bubble canopy.
 
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Could it have been possible that NA used ONLY the plexi glass portion of the canopy and modified it to fit the frame on these first aircraft?

I did work with a company called Cerrican (sp?) Aircraft transparencies located in Sylmar Ca. They made the first canopy for the F-22 and also made F-16 canopies there. If they had a scrap F-16 canopy they would sell the plexi glass bubble. I was told that homebuilders, Unlimited racers and even boat racers bought their scrap canopies and cut them down to fit a frame on their boat or aircraft.
 
That's the only possibility I can think of Joe.
BUT - the Perspex part alone is 2 feet shorter than the P51D equivalent part, a lot narrower, and lower in side profile! This would mean a very odd-shaped frame, not to mention an awkward, if not impossible, joint/seal at the forward edge of the canopy to the windscreen.
Bearing in mind the fuel tank and radio equipment fit to the rear of the P51D cockpit, all covered by the canopy, and remembering what Bill stated about the prototype 'D' and its canopy, borne out by photos, I can't see that a Typhoon canopy, custom-framed or not, would even partly fit, let alone be safe, sealed and aerodynamically sound !
 
Back to the dorsal fin. That would explain my confusion with this photo: Most photos I have seen of this bird, she has no dorsal fin.
 
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from P-51 Mustang Variants - P-51D - MustangsMustangs.com a pretty good site...

The signature change in the P-51D line was the new bubble canopy. The U.S. was behind the Brittish in canopy development. A Brittish company had designed and built the "Malcolm Hood" which improved visibility to the rear of the P-51B/C models. The U.S. was not unaware of the advantages of a bubble canopy design. NAA had built a wooden model of the P-51 with a bubble canopy for wind tunnel testing. The technology to build large curves of plexiglass "distortion free" at that time was being invented and developed.

The Brittish had figured out how to make a bubble (also called "teardrop") canopy with unobstructed 360 degree view and they were beginning to use them on the latest model of Spitfires and Typhoons. The U.S. Army sent Col. Mark Bradley to England in January of 1943 to find out the workings of this new canopy and then find a way to get them on U.S. fighters. Bradley returned and began to pursue ways to incorporate the new style. The first U.S. fighter so tested was a Republic P-47.
 

the 85 gallon fuse tank was put in earlier versions and way before the fin mod. they took the off full but burned them down to 3o some gallons before switching to the drop tanks. with that tank full maneuvering was somewhat difficult. i believe it could be snap rolled. gregp and drgondog could say if they can or not since they have flown them.
 
On the Typhoon canopy issue, we have had vets show up as well as people who built Northa American, Douglas, Northrop, Consolidated, and Vultee products. Not surprising since tey were all built around this area. At least two guys showed up with Noth American notebooks detailing installation of a Typhoon canopy on a modified B-model Mustang.

I had and have no reason to doubt them. They were just happy I could let them up into a Mustang cockpit again.

Again, you can believe it or not in peace. I do becasue I saw the notes and tech orders. If you don;t, that's OK, too ... I understand. In the end, it doesn't matter becasue they D's were built and made history anyway.
 
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