# P-51B Mustang - The Bastard Stepchild that Saved the 8th AF has been sent by Osprey Publications for Print.



## drgondog (Feb 16, 2020)

Too many to mention here from tis forum have contributed over the years. Than you all and you are remembered in the Acknowledgements. The P51SIG group was probably the single most active contributor pool.

Thanks to all of you - and particular thanks to Bob Gruenhagen.

Regards,

Bill

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## CORSNING (Feb 16, 2020)

Congratulations Bill.
All the best to you and your works.
Jeff


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## DarrenW (Feb 16, 2020)

drgondog said:


> Too many to mention here from tis forum have contributed over the years. Than you all and you are remembered in the Acknowledgements. The P51SIG group was probably the single most active contributor pool.
> 
> Thanks to all of you - and particular thanks to Bob Gruenhagen.
> 
> ...


 Very nice Bill, I'm positive it will be one of Osprey's bestsellers! How long before it will be available for purchase?


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## GrauGeist (Feb 16, 2020)

Fantastic news. Bill!

Can't wait to get a copy


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## jetcal1 (Feb 16, 2020)

Thank you for sharing the news! That's exciting news.


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## tomo pauk (Feb 16, 2020)

Amazing. And I sorta know the author

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## airminded88 (Feb 16, 2020)

Having enriched my knowledge substantially on the 355th FG operational history and 8th AF operations in general through Bill's excellent previous works, I am definitely looking forward to add Bill's latest effort into my book collection.
Congratulations Bill.

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## pbehn (Feb 16, 2020)

Great stuff Bill.


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## Micdrow (Feb 17, 2020)

Awesome news Bill, congrat's


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## Dana Bell (Feb 17, 2020)

Hi Bill,

Looking forward to it! Have they given you a release date?

Cheers,



Dana


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## drgondog (Feb 18, 2020)

Dana Bell said:


> Hi Bill,
> 
> Looking forward to it! Have they given you a release date?
> 
> ...


June 2020.. was orginally targeted for November 2019 but various edits slowed it down.


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## Barrett (Feb 21, 2020)

I worked with Bill at Champlin Museum Press in the 80s when we published his excellent 355th FG history. Am anticipating the 51B volume just as much!


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## drgondog (Feb 21, 2020)

Barrett said:


> I worked with Bill at Champlin Museum Press in the 80s when we published his excellent 355th FG history. Am anticipating the 51B volume just as much!


Barrett was the long suffering editor that nurtured Angels, Bulldogs and Dragons into life 30+ years ago..

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## pbehn (Feb 21, 2020)

drgondog said:


> Barrett was the long suffering editor that nurtured Angels, Bulldogs and Dragons into life 30+ years ago..


I just got Bulldogs and Dragons as a birthday present from my wife, she is one of those annoying people who listens and remembers conversations then uses her detective genes.

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## Airframes (Feb 21, 2020)

Looking forward to this Bill - pity you're so far away, or i'd ask you to sign my copy when I buy it !!
Ans congratulations on getting this to print.


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## TheMadPenguin (Feb 25, 2020)

"pity you're so far away, or i'd ask you to sign my copy when I buy it !! "
Books mail cheap. Buy, mail it to him, enclose return postage, and it's done!


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## DerAdlerIstGelandet (Feb 25, 2020)

Looking forward to this book.

I will have to search for Bulldogs and Dragons as well.


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## drgondog (Feb 26, 2020)

Note to all: If you want my sorry signature and blessing in any book I rote - send me a self addressed envelope to; 10148 Bluebonnet, Scurry TX 75158.

Tell me which name you want in the book.

I will write a personal note on a sticky back 4x5 label and send back to you. Beats the hell out of shipping a book two ways.

Thank all of you for your kind remarks.

Bill


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## Peter Gunn (Feb 26, 2020)

Congrats Bill, I can hardly wait to read it!


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## Barrett (Mar 5, 2020)

<div data-xf-p="1">Barrett was the long suffering editor that nurtured Angels, Bulldogs and Dragons into life 30+ years ago..</div><div data-xf-p="1"><br></div><div data-xf-p="1"></div>

Hey! There was no suffering in the process! It was a (very) rare pleasure to work on a serious history book written by the son of a significant "player."

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## MakerDude (Mar 24, 2020)

Nice amazon page

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## MakerDude (Mar 24, 2020)

Out of curiosity in your research did you find out when Republic and North American were asked to extend the range of their fighters? Also how much emphasis was placed on this. Often the manufacturers were giving multiple requests some more important than others.


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## tomo pauk (May 14, 2020)

Ordered at Osprey web-shop (that I can just recomend for the people at Old Continent)

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## drgondog (May 14, 2020)

MakerDude said:


> Out of curiosity in your research did you find out when Republic and North American were asked to extend the range of their fighters? Also how much emphasis was placed on this. Often the manufacturers were giving multiple requests some more important than others.



The Arnold Fighter Conference drove the priorities to get Materiel Command off their asses for long range combat tanks - Feb 20 1942. Also set as a priority was to urge the US fighter manufacturers to increase internal fuel. That said Barney Giles, Chief of Air Staff lit the fire under NAA, Lockheed and Republic to prioritize schemes to increase internal fuel in the P-51B, P-38J and P-47D on July 5, 1943. NAA had a stainless steel 90gal (not combat) fuse tank installed and flown in 43-12112 on July 16, 1943.Lockheed was next with 2x55gal LE tanks and Republic last with 65gal increase in the P-47D-25,


tomo pauk said:


> Ordered at Osprey web-shop (that I can just recomend for the people at Old Continent)



Many contributors from this website - Tomo was very important at getting images of the specific LW fighters I needed to make some points about evolution to fight the 8th AF

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## B-25 Pilot (May 14, 2020)

wow, congrats. I will definitely try to buy it. I can't wait!


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## ThunderChief76 (May 15, 2020)

I pre-ordered a copy on Amazon! Can’t wait to get my hands on it.


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## drgondog (Aug 6, 2020)

US Customs continues to be the hold up. K got their block in early July. Amazon states October now for US deliveries.

Amazon product

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## ThunderChief76 (Aug 6, 2020)

I ended up getting a copy from the Book Depository. Got it two weeks ago. Left a review in the new book thread.

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## jetcal1 (Aug 6, 2020)

drgondog said:


> US Customs continues to be the hold up. K got their block in early July. Amazon states October now for US deliveries.
> 
> Amazon product



Well, just ordered mine today.

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## drgondog (Aug 7, 2020)

I'm seeing faster delivery on Ebay and a wide range of prices for new.


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## MakerDude (Aug 13, 2020)

I bought mine on Kindle. Got it now

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## drgondog (Aug 13, 2020)

MakerDude said:


> I bought mine on Kindle. Got it now


already a lot of Kindle sales.

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## drgondog (Aug 13, 2020)

MakerDude said:


> Out of curiosity in your research did you find out when Republic and North American were asked to extend the range of their fighters? Also how much emphasis was placed on this. Often the manufacturers were giving multiple requests some more important than others.


Yes. Two major drivers. Arnold Fighter Conference in Jan 1942 which drove Materiel Command to develop combat tanks. ACOS General Barney Giles issuing 'instructions in July 1943 to NAA, Republic and Lockheed to increase 'internal fuel'. NAA delivered prototype SS fuselage 90 gal fuel tank (not self sealing) 10 days later. Lockheed had a 80 gal tank resdy for tail cone but abandoned that line and went for leading edge tanks for the P-38J. Republic was far behind because of major design issues to modify wings (P-47M/N) or increase fuselage fuel (305 to 370) for P-47D-25 - which required extensive mod under and aft of cockpit.


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## jetcal1 (Aug 13, 2020)

drgondog said:


> Note to all: If you want my sorry signature and blessing in any book I rote - send me a self addressed envelope to; 10148 Bluebonnet, Scurry TX 75158.
> 
> Tell me which name you want in the book.
> 
> ...


Well Sir,
I'm ashort drive away and when this is covid stuff is all said and done?
It would be an honor to provide a few rounds of your favorite libation as a thank you for your signature.

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## drgondog (Aug 14, 2020)

jetcal1 said:


> Well Sir,
> I'm ashort drive away and when this is covid stuff is all said and done?
> It would be an honor to provide a few rounds of your favorite libation as a thank you for your signature.


Be glad to sign - where do you live?

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## Peter Gunn (Aug 14, 2020)

Wait... we have to pay money for this book?

Obviously kidding, as a frustrated author that's never published anything but crappy posts on message boards I'm a bit envious but also very happy for you and offer hearty congratulations on another tome for the library. Well done!

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## jetcal1 (Aug 14, 2020)

drgondog said:


> Be glad to sign - where do you live?


Near Roanoke. Probably around 70-80 miles away. You know, just on the "other side" of the "Metroplex"

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## drgondog (Aug 15, 2020)

jetcal1 said:


> Near Roanoke. Probably around 70-80 miles away. You know, just on the "other side" of the "Metroplex"


I'm in Dallas and Waxahachie and Lewisville often.


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## jetcal1 (Aug 17, 2020)

My copy arrived today. Browsed it for 3 or 4 minutes. the initial impression is very, very favorable. The appendices look good, the bibligraphy looks to cover a wide range of archival source materia, the pre-history chapter appears to be relatively complete at first glance. And while I know we're supposed to not make snap judgments on first appearances, my guess is this is probably a definitive level book from both a development and operational use perspective. 

Very, very pleased.

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## drgondog (Aug 18, 2020)

Thank you for your thoughtful comments. The Book, while written 'largely' by me (Colin Ford wrote huge RAF contributive chapter) was a huge collaborative effort with my co-author Lowell Ford.. and co-editor Bob Gruenhagen.

The style regarding content narrative was mine so any confusion in moving between NAA and AAF and ETO in chronological order can be pinned on me.

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## Peter Gunn (Aug 18, 2020)

drgondog said:


> *SNIP*
> 
> The style regarding content narrative was mine so any confusion in moving between NAA and AAF and ETO in chronological order can be pinned on me.


I'll remember that, it may come in handy when I give my scathing review of said tome, which will not arrive until the 24th of August, so you're safe until then.

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## overbeck (Sep 5, 2020)

I read the Kindle version. It's great to get the finer details about how the Mustang came to be. One question: why do you refer several times to the V-1710-45 as having a two speed drive? All available information says it had a fluid coupling on the auxiliary stage.


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## pbehn (Sep 5, 2020)

overbeck said:


> I read the Kindle version. It's great to get the finer details about how the Mustang came to be. One question: why do you refer several times to the V-1710-45 as having a two speed drive? All available information says it had a fluid coupling on the auxiliary stage.


Ive not read the book yet but wasn't the V-1710 the Allison engine? The Mustang P-51B/C was powered by the Packard V-1650 licence built RR Merlin?


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## overbeck (Sep 5, 2020)

pbehn said:


> Ive not read the book yet but wasn't the V-1710 the Allison engine? The Mustang P-51B/C was powered by the Packard V-1650 licence built RR Merlin?



The Allison, yes. The book mentions the proposal to use the two-stage Allison and NAA's study of it, which concluded they would need to move the wing so far forward it was unacceptable, plus NAA found Allison's customer service to be lacking (probably mostly because of early production chaos).


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## Dash119 (Sep 5, 2020)

Interestingly, the lightweight XP-51J did fly with a two stage Allison V-1710 and I don't think it required movement of the wing. They did eliminate the carb air intake from the engine cowling, and instead drew the intake air from the belly scoop. The Allison model was the V-1710-119...

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## overbeck (Sep 5, 2020)

Dash119 said:


> Interestingly, the lightweight XP-51J did fly with a two stage Allison V-1710 and I don't think it required movement of the wing. They did eliminate the carb air intake from the engine cowling, and instead drew the intake air from the belly scoop. The Allison model was the V-1710-119...



Reading between the lines of NAA's decision, it wasn't that fitting the Allison was impossible, but they had a better option in the Merlin, and maybe they suspected the two-stage Allison would perform poorly (which it did; later the NACA had to fix up basic design errors in the V-1710-93 auxiliary stage), so they pushed the unacceptability of the design changes as much as possible. FWIW I don't doubt the wing movement, as they had to move it slightly for the Merlin too, and the two-stage Allison was much more awkward.


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## overbeck (Sep 6, 2020)

Another question for drgondog: your book states, "Atwood approved RD-1062 to study airframe and cooling system changes that would arise from the installation of the Continental V-3420 engine into the NA-73 airframe," and it mentions a "Continental V-3420 X engine" in another couple of places. Surely you mean the Continental XI-1430 V12? Allison made a V-3420 but there's no way it was a canditate for the Mustang.


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## drgondog (Sep 6, 2020)

overbeck said:


> Another question for drgondog: your book states, "Atwood approved RD-1062 to study airframe and cooling system changes that would arise from the installation of the Continental V-3420 engine into the NA-73 airframe," and it mentions a "Continental V-3420 X engine" in another couple of places. Surely you mean the Continental XI-1430 V12? Allison made a V-3420 but there's no way it was a candidate for the Mustang.


You are correct - my editor made that correction to the final draft and I missed it. If there is an 'errata sheet' I will correct that plus a couple of other edits that I missed.

As to the V-1710-45. It was so described in NAA correspondence from Rice to Atwood as the 'two stage supercharged Allison with the auxiliary second stage'. No it didn't have the pressure-altitude governed two speed gearbox or intercooling of the Merlin 60 series.

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## overbeck (Sep 6, 2020)

drgondog said:


> You are correct - my editor made that correction to the final draft and I missed it. If there is an 'errata sheet' I will correct that plus a couple of other edits that I missed.



Thanks for explaining.



drgondog said:


> As to the V-1710-45. It was so described in NAA correspondence from Rice to Atwood as the 'two stage supercharged Allison with the auxiliary second stage'. No it didn't have the pressure-altitude governed two speed gearbox or intercooling of the Merlin 60 series.



The reason I ask is because it's described in your book as, "Allison's proposed two-speed/two-stage supercharged V-1710-45."

Another, very minor typo is "V-1710-39/FSR" instead of "F3R".

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## drgondog (Sep 6, 2020)

overbeck said:


> Reading between the lines of NAA's decision, it wasn't that fitting the Allison was impossible, but they had a better option in the Merlin, and maybe they suspected the two-stage Allison would perform poorly (which it did; later the NACA had to fix up basic design errors in the V-1710-93 auxiliary stage), so they pushed the unacceptability of the design changes as much as possible. FWIW I don't doubt the wing movement, as they had to move it slightly for the Merlin too, and the two-stage Allison was much more awkward.


Actually, it would have required more significant changes than the Merlin conversion and delays to re-tool totally unacceptable to BAM/RAF.

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## pbehn (Nov 25, 2020)

K
 Koopernic
Here


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## kool kitty89 (Apr 3, 2022)

On the issue of the V-1710-45 (and many or possibly all auxiliary supercharger installations on the V-1710), it appears that the aux stage used a fluid coupling, like an automatic transmission's toque converter, similar to the DB-601/605/603 and some R-2800 aux stages (and the single stage one used on the F8F). This is why you get the power curves you do with the similar -47, -93, -117, and -109 used in the XP-63 and P-63 and likely why you get the somewhat confusing wording of "Allison V-1710-47 engine was fitted with a second hydraulic turbosupercharger" in Joe Baugher's XP-63 article. (a fluid coupling uses a matched pair of impeller and turbines in oil/hydraulic fluid, so the supercharger is literally driven by a hydraulic turbine)
Bell XP-63 Kingcobra

This would also explain the aux stage 1710s only having 2 supercharger earing speeds listed for 2-stage variants. (one number for the integral supercharger and one for the full/locked condition of the aux stage) Hence also why there's only a take-off and high altitude rating for those engines, just like single-stage single-speed ones, and it would refer to the full/locked position of the fluid coupling. 

So those V-1710s are 2-stage, but not 2-speed: the integral stage is fixed speed and the aux stage is variable. (I also see no references to indicate neutral+high+low mechanical drive gearing on aux stages like some P&W engines used)

All those engines should be pressure-altitude governed using a throttle setting to select the manifold pressure rather than manually controlling the throttle plate. This feature was already present in single-stage V1710s with automatic boost control (throttle sets the manifold pressure and the throttle plate is automatically adjusted to provide that manifold pressure). The difference here being the throttle plate would be wide open at all but low altitude and low pressure settings (as seen in P63 testing) and beyond that the pressure is controlled by allowing more oil into the fluid coupling housing.

In USAF charts the -45 is described as "Similar to -39 except: auxiliary second stage automatic boost control, and aneroid unit, PT-13E carburetor." And the reference to the aneroid unit may be the mechanism used for boost control (the aneroid unit should be the mechanical air pressure gauge used in conjuction with manifold pressure position set by the throttle lever).

The USAF charts also only have a 9.5" diameter listed for several aux stage V-1710 models (including the -45 and -47) but 9.5" and 12.18" for some later models (and 10.25 and 12.18 for later yet). However, this may simply imply that both stages are of 9.5" diameter on the examples that only list 9.5" (note: while the diameter may be the same, the impeller dimensions could still differ, particularly in height/chord of the impeller/vanes, making overall volume larger for the same diamter; that would make sense for providing higher volume at lower pressure from the aux stage to the integral stage).




There's no intercooler, but you have reduced charge heating due to the variable supercharger speed and avoid throttle plate losses at all wide-open conditions (Junkers also avoided that with use of a swirl throttle), but you do need additional oil cooling and an oil/air separator to account for the oil heating from the fluid coupling and the air churned up inside it at medium altitudes.


In any case, the significant increase in length of the auxiliary supercharger installation is what made it more difficult to fit to existing aircraft and would have delayed production compared to the P-51B's merlin installation. (presumably using a bevel geared drive at 90 degrees from the accessory drive shaft on the V-1710 could've allowed a side-mounted aux stage similar to the DB and Jumo engines, and avoided the increase in length, but for whatever reason Allison didn't do that, maybe due to a potential increase in width/frontal area and/or to minimize weight, but that's pure conjecture: albeit if the USAF chart is correct, the -45 was only 1515 lbs, lighter than the 1520 lbs for the single-stage V-1650-1 merlin, let alone the 1690 to 1745 lbs for the 2-stage merlins)

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## drgondog (Apr 5, 2022)

kool kitty89 said:


> There's no intercooler, but you have reduced charge heating due to the variable supercharger speed and avoid throttle plate losses at all wide-open conditions (Junkers also avoided that with use of a swirl throttle), but you do need additional oil cooling and an oil/air separator to account for the oil heating from the fluid coupling and the air churned up inside it at medium altitudes.


The problem of detonation at boosts higher than 63" was never solved for the F/82 V-1710-143/-145. According to NAA Schmued, NAA fitted a backfire screen and sent the data to Allison - but Allison refused to modify the engine and effectively got away with telling both AAF/USAF and NAA to pound sand. IIRC the MP was set at 61" thereafter, dramatically reducing the performance of the F-82 vs the XP-82 and P-82B with Merlins.


kool kitty89 said:


> In any case, the significant increase in length of the auxiliary supercharger installation is what made it more difficult to fit to existing aircraft and would have delayed production compared to the P-51B's merlin installation. (presumably using a bevel geared drive at 90 degrees from the accessory drive shaft on the V-1710 could've allowed a side-mounted aux stage similar to the DB and Jumo engines, and avoided the increase in length, but for whatever reason Allison didn't do that, maybe due to a potential increase in width/frontal area and/or to minimize weight, but that's pure conjecture: albeit if the USAF chart is correct, the -45 was only 1515 lbs, lighter than the 1520 lbs for the single-stage V-1650-1 merlin, let alone the 1690 to 1745 lbs for the 2-stage merlins).


The length was a 'killer'. Allison may have been encouraged to make the changes if they believed that NAA and the orders for Packard Merlins would be replaced by the Allison. By that time, AAF-MC/RAF/NAA were in firm agreement with P-51B/1650-3 and no hope for Allison to recapture Mustang business.

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## Wild_Bill_Kelso (Apr 24, 2022)

drgondog said:


> Too many to mention here from tis forum have contributed over the years. Than you all and you are remembered in the Acknowledgements. The P51SIG group was probably the single most active contributor pool.
> 
> Thanks to all of you - and particular thanks to Bob Gruenhagen.
> 
> ...



Congrats, and great title!

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