Why were most early WW2 fighters designed with limited rear visibility?

[drgondog]

I had seen a couple before, but only a very small minority of the P-51B-C photos I've seen, and I have read the "directional stability loss with the loss of side area" explanation in several publications, so that was what I was going with.

Drgondog has provided original documentation showing that the instability had a different cause than the canopy change, so I am now better informed!

A good source (Very Good) is Birch's "Rolls-Royce and the Mustang".

And yes, someone in the distant past concluded that the 'loss of side area' was the root cause - and 100 more experts copied and pasted. Looking into obscure reports at NAA discussing empennage failures draws your attention to the design and installation of the Reverse Rudder Boost tab which was released at same time (kit form) as Dorsal fin for both P-51B and P-51D in April 1944. Later a T.O. was released to beef up the Stab spar and doubler attaching fin to Stab and bulkead.

The problem to be solved was hard rudder input to damp natural Yaw response to roll - combined with the prop vortex applying asymmetric loads to the H.Stab and Fin/Rudder.

Anecdotally, my father resisted (unsuccessflly) the installation of reverse rudder boost kit because he disliked the reduction in roll authority. His favorite WWII manuever ship was the P-51B/C with Hood and no RRBT installed. To him, the purest manuever ship was the P-51A and claimed the P-51H was close.

 

[pinehilljoe]

The P-39 Wins again, state of the art canopy visibility:

 

[Admiral Beez]

The Italians had a good canopy with the Caproni Vizzola F.5.

But with the exception of the Reggiane Re.2000 Falco, I believe the Italians relied on either open cockpits or traditional rear-bulkhead canopies until the post-war Fiat G.59 below.

 

[PlasticHero]

Just a few years before the P-51 was designed, NA built this iconic aircraft. AT-6 Texan.

 

[Snautzer01]

Just a few years before the P-51 was designed, NA built this iconic aircraft. AT-6 Texan.
View attachment 737385

Every thing is just right at this thing. Even the sound it makes and all angles are Hollywood.
Bet it can take a bad landing too and just roll it off. Did i ever tell the thing about Jean Salis performing?

 

[pbehn]

Just a few years before the P-51 was designed, NA built this iconic aircraft. AT-6 Texan.
View attachment 737385

An important aircraft in many ways apart from what it did as a trainer. There are important lessons in production engineering that you learn when you produce your first aircraft. Mistakes are hard to undo on the aircraft concerned but easy to avoid on future designs. One client of the Texan was the British, the Texan did more than any salesman could to demonstrate to the British that NAA could design and produce modern monoplanes. The Texan played its part in persuading the British that NAA could produce what became the P-51 not just design it. When the British went along with the NAA proposal to produce a better fighter than the P-40, it was not quite the "shot in the dark" that the legend says it was.

 

[SaparotRob]

An important aircraft in many ways apart from what it did as a trainer. There are important lessons in production engineering that you learn when you produce your first aircraft. Mistakes are hard to undo on the aircraft concerned but easy to avoid on future designs. One client of the Texan was the British, the Texan did more than any salesman could to demonstrate to the British that NAA could design and produce modern monoplanes. The Texan played its part in persuading the British that NAA could produce what became the P-51 not just design it. When the British went along with the NAA proposal to produce a better fighter than the P-40, it was not quite the "shot in the dark" that the legend says it was.

According to a new video by Greg's Planes, Trains and Automobiles (whatever), it's actually Fokker.

 

[pbehn]

According to a new video by Greg's Planes, Trains and Automobiles (whatever), it's actually Fokker.

Greg is always great for banter and cod history. When a learned gentleman of this parish points out his cluelessness his response is "I have another video on that" or "I have already covered that". Of course all allied success is down to Germany and its complete superiority in all things, only a fool would believe otherwise.

 

[drgondog]

According to a new video by Greg's Planes, Trains and Automobiles (whatever), it's actually Fokker.

Ahhh, I just dropped about three large paragraphs suggesting that he (Greg) research which company Kindelberger, Atwood, Smithson (production), Schleicher (Structures), Rice (Engineering),Baldwin (project management), etc - came from.

Hint - just down the street a ways from the Inglewood plant. The one and ONLY key manager/exec that I know came from Fokker was Schmued and he was just recently promoted by Dutch to project manage GA-15 (XO-47) while employed with GMAC via Fokker.

When Kindelberger was hired by GMC/GMAC - by Ernie Breech (post war CEO of Ford) but GM Board when he hired Kindelberger in 1935 - he brught nearly his entire Engineering and Production exec management team from Douglas. They 'knew a few thangs' about quality design and production while rolling out among other things, the DC-1 & DC-2.

I have no idea what he wuz thinkin' when he surprised everyone with the mysterious 'progenitor' airframe team from 'club Fokker -US'.

 

[SaparotRob]

Ahhh, I just dropped about three large paragraphs suggesting that he (Greg) research which company Kindelberger, Atwood, Smithson (production), Schleicher (Structures), Rice (Engineering),Baldwin (project management), etc - came from.

Hint - just down the street a ways from the Inglewood plant. The one and ONLY key manager/exec that I know came from Fokker was Schmued and he was just recently promoted by Dutch to project manage GA-15 (XO-47) while employed with GMAC via Fokker.

When Kindelberger was hired by GMC/GMAC - by Ernie Breech (post war CEO of Ford) but GM Board when he hired Kindelberger in 1935 - he brught nearly his entire Engineering and Production exec management team from Douglas. They 'knew a few thangs' about quality design and production while rolling out among other things, the DC-1 & DC-2.

I have no idea what he wuz thinkin' when he surprised everyone with the mysterious 'progenitor' airframe team from 'club Fokker -US'.

I had a feeling you might drop by.
I was looking forward to your response!

 

[pbehn]

Ahhh, I just dropped about three large paragraphs suggesting that he (Greg) research which company Kindelberger, Atwood, Smithson (production), Schleicher (Structures), Rice (Engineering),Baldwin (project management), etc - came from.

Hint - just down the street a ways from the Inglewood plant. The one and ONLY key manager/exec that I know came from Fokker was Schmued and he was just recently promoted by Dutch to project manage GA-15 (XO-47) while employed with GMAC via Fokker.

When Kindelberger was hired by GMC/GMAC - by Ernie Breech (post war CEO of Ford) but GM Board when he hired Kindelberger in 1935 - he brught nearly his entire Engineering and Production exec management team from Douglas. They 'knew a few thangs' about quality design and production while rolling out among other things, the DC-1 & DC-2.

I have no idea what he wuz thinkin' when he surprised everyone with the mysterious 'progenitor' airframe team from 'club Fokker -US'.

i couldnt find your replies?

 

[SaparotRob]

Ditto.

 

[PlasticHero]

Exactly, I had just watched that one and when the Texan was shown, I thought, "They could easily have made a canopy with better rear vision".

 

[BiffF15]

i couldnt find your replies?

I think he may be referencing his replies to Greg regarding the video (?)…

 

[pbehn]

I think he may be referencing his replies to Greg regarding the video (?)…

I was looking on the video web site comments, but after it gets to a few hundred replies my computer slows to the point that it takes hours (literally) to scroll.

 

[MiTasol]

Hi,
I believe that there were some additional early war aircraft out there that "at least seemed to have" made an attempt at good rearward visibility, such as the Seversky P-35, the Bell P-39, and the Brewster F2A.

View attachment 729013View attachment 729014View attachment 729015

[Images via Wikipedia]

In actual fact the rear visibility on the P-39 was crap because that is where they stuck a lot of the radio equipment. It actually shows in the photo you posted.

 

[drgondog]

i couldnt find your replies?

I'll look. Greg did delete my first post on the P-51H then claimed he didn't do it, 'musta been youtube'.

I laid out a couple of paragraphs on the geneology of Fokker, the GMC acquistions leading up to the NAA consolidation/absorption of Fokker, GMAC, Berliner-Joyce with newly hired Kindelberger leading NAA.

 

[pbehn]

I'll look. Greg did delete my first post on the P-51H then claimed he didn't do it, 'musta been youtube'.

I laid out a couple of paragraphs on the geneology of Fokker, the GMC acquistions leading up to the NAA consolidation/absorption of Fokker, GMAC, Berliner-Joyce with newly hired Kindelberger leading NAA.

Borrowed by wifes computer and found them well two anyway.

 

[PlasticHero]

Look at the tail of the Texan, it looks pretty thin and with a "sorta" bubble canopy, the theory of lack of directional stability on the Mustang does seem less likely to me. I agree with drgondog

 

[fannum]

I'd suggest that a lot of the reason for a turtleback was tradition ... since biplane headrests growing, it just was the norm. Note that almost all light planes and ever training gliders of the era used the 'turtle back' planform, and after the war, they were removed for spotter plane purposes (Cessna 170>L-19), and surplus TGs in glider clubs were often 'flat-topped for efficiency and thermaling visibility. (Laister Kauffman TG-4A/LK-10A flat top)

A secondary reason may be structural, especially as speeds increased, and stresses due to tail feather control forces got greater. (although I've always felt the pretty CW-21 looked as if was designed by a bean counter trying to reduce aluminum costs!)

Finally, I too have been puzzled to see razorback P-47s and P-51s "upgraded" with dorsal fins.