XP-39 II - The Groundhog Day Thread

[GrauGeist]

Bell had industry experience, but they didn't have an experienced factory staff. And understanding a business is not the same as running one; there is a learning curve there in everything from hiring to marketing to quality control to anticipating industry direction.
Bell didn't have to learn everything from scratch, but he had to build the company from scratch, except for the building. Consolidated left that and Bell grabbed it.
An illustration: Curtiss delivered 1,200+ P-36/P-40s in 1940. Bell delivered 926 P-39s in 1941 (plus 13 prototypes in 1940).
As both companies ramped up production, Curtiss went to 2,200+ in '41, 4,400+ in '42, and 4,200+ in '43. Bell increased more slowly at first, 926 in '41, 1,973 in '42, then passed Curtiss with 4,900+ in '43. In addition, Bell was able to develop a significantly better fighter using the same basic configuration, the P-63, while Curtiss never did find an acceptable P-40 follow-on. Lessons well learned and applied.

Curtiss had other aircraft being produced (C-46, SB2C, CW-22, AT-9, O-52, SC and the ill-fated SO3C) so their manufacturing capacity was stretched thin (which is why North American was aproached by the BPC to build them Hawk 81s).
All told, Curtiss produced close to 14,000 P-40 types which is a bit more than Bell's P-39 numbers, which was less than 10,000.
Which is impressive, considering that the Hawk 81 was a follow-on to the Hawk 75. The fact that Curtiss couldn't develop the P-40 any further (not for the lack of trying, however) is not surprising, since the airframe was a mid-30's design.

 

[GregP]

As someone formerly in the Defense Industry, Casey is the person who produced the chart, and Robinson is the person who checked that the chart was drawn correctly from the data supplied. Drawing "checkers" sometimes find errors and it gets corrected when found, if the error is actual.

Hi P-39 Expert,

The chart is, in fact, pretty far off, regardless of weight. It was established more than 60 pages ago that the drag coefficient of the XP-39 as it was built and before being modified into the XP-39B, would not allow 390 mph at either 1,050 or 1,150 hp. This chart of what is certain to be projected performace will not resurrect the debate and result in a different analysis if the analysis is done correctly since it was done correctly the first time. Time doesn't change the outcome when the facts are correct.

 

[P-39 Expert]

Yeah, I've seen the 390mph figure repeated on many sources, but no primary source of origin for it.

What is odd for a projected graph is the line labeled "Actual Time To Climb Curve" and a dashed line that I assume is the projected time to climb. Also, the abrupt 'switch' from "Military Power" to "Normal Power" at around 19,000 feet on the Rate Of Climb curve as indicated by the switch of solid and dashed lines.
This chart is "Figure 8" of some report. Also of interest would be "Tables VI and VII."

I also wonder who "Asey" (Casey?) and "Robinson" were.

If someone could find Bell report "12Y005" we'd know. Maybe.

The Allison (as with other American aircraft engines at the time) had a 5 minute limit for military power, so the pilot had to reduce to normal power at the five minute mark of his climb. The five minute limit was increased to 15 minutes in mid 1942. The dashed line above 19000ft represents the climb rate at military power which was available if the pilot hadn't just used up his five minutes. IOW pilot is cruising along above 19000ft and spots an enemy and goes to military (combat) power and can climb at the dashed line rate. I didn't explain that very well, hope it made some sense.

 

[jmcalli2]

As someone formerly in the Defense Industry, Casey is the person who produced the chart, and Robinson is the person who checked that the chart was drawn correctly from the data supplied. Drawing "checkers" sometimes find errors and it gets corrected when found, if the error is actual.

That I know, but it does not tell us WHO those men were, only WHAT their jobs were.

The question is, what the chart is supposed to communicate. Rehashing what was in "several pages ago" does not contribute to finding out what it was for or what the other 30 pages of the report it was a part of said.

 

[jmcalli2]

The Allison (as with other American aircraft engines at the time) had a 5 minute limit for military power, so the pilot had to reduce to normal power at the five minute mark of his climb. The five minute limit was increased to 15 minutes in mid 1942. The dashed line above 19000ft represents the climb rate at military power which was available if the pilot hadn't just used up his five minutes. IOW pilot is cruising along above 19000ft and spots an enemy and goes to military (combat) power and can climb at the dashed line rate. I didn't explain that very well, hope it made some sense.

I think you explained it pretty well, thanks.

 

[XBe02Drvr]

Just curious; did you work at the GE plant in Schenectady or Syracuse?

Neither. In the 50s through the 80s GE Armament Division was housed in the former Bell Aircraft Lakeside Plant in Burlington VT, conveniently within commuting distance of the VT National Guard Underhill Artillery Range. I believe it's now in Siberacuse.
"Sunshine everywhere else, it's cloudy in Syracuse. Cloudy everywhere else, it's raining in Syracuse. Raining everywhere else, it's snowing in Syracuse. Snowing everywhere else, it's an effing blizzard in Siberacuse!"
"Indefinite, sky obscured, estimated ceiling two hundred broken, three hundred overcast, visibility one half mile in snow and blowing snow, wind two zero zero at two five, gusts four zero, altimeter two niner eight two. Expect ILS Runway two eight. Two eight RVR eighteen hundred, variable sixteen hundred. Braking action poor."
"Metro Air two five one four, cleared to land two eight, best speed to the runway, jets to follow. Plan exit taxiway Bravo, Charlie and Delta unavailable. Piedmont two four three, you're overtaking traffic ahead, expedite your speed reduction to one six zero, be ready for a go around or delayed landing clearance.... Metro, thanks for Bravo, hold short of the parallel, Ground point nine. Piedmont two four three cleared to land two eight. Roll it on down to Foxtrot, Charlie and Delta closed for snow removal."

 

[jmcalli2]

Neither. In the 50s through the 80s GE Armament Division was housed in the former Bell Aircraft Lakeside Plant in Burlington VT, conveniently within commuting distance of the VT National Guard Underhill Artillery Range. I believe it's now in Siberacuse.
"Sunshine everywhere else, it's cloudy in Syracuse. Cloudy everywhere else, it's raining in Syracuse. Raining everywhere else, it's snowing in Syracuse. Snowing everywhere else, it's an effing blizzard in Siberacuse!"
"Indefinite, sky obscured, estimated ceiling two hundred broken, three hundred overcast, visibility one half mile in snow and blowing snow, wind two zero zero at two five, gusts four zero, altimeter two niner eight two. Expect ILS Runway two eight right, departures two eight left. Two eight right RVR eighteen hundred, variable sixteen hundred. Braking action poor."
"Metro Air two five one four, cleared to land two eight right, best speed to the runway, jets to follow. Plan exit taxiway Bravo. Piedmont two four three, expedite speed reduction to one six zero, be ready for a go around or delayed landing clearance. Metro, thanks for Bravo, hold short of the parallel, Ground point nine. Piedmont two four three cleared to land two eight right. Roll it on down to Foxtrot, Charlie and Delta closed for snow removal."

Cool.

I just asked because I grew up in Syracuse, my Mom worked at GE making TVs in the '60s. That Syracuse GE facility, actually in Liverpool NY, is Lockheed-Martin now, recently got a big sonar contract. Could still be some GE there too.

I worked in the Albany area for a time, passed through the huge Schenectady GE campus there quite often.
Along with the Watervliet Arsenal, I drove past that about every day for a year. Interesting place.

I've been to Burlington a few times. Lovely town.

One of my first jobs in the early 80s had me going around the SAC base at Griffiss AFB in Rome. B-52s and F-106s. Saw a Navy T-2 Buckeye parked in front of the tower once. Very interesting place.

BTW, Syracuse is 40 inches short of their usual snowfall for this time of year. The Lake Effect seems to have moved South about 70 miles; Binghamton is 28 inches above their usual snowfall right now.

Worst thing about flying (commercial) out of SYR is they don't remember how to de-ice more than one plane at a time until mid January.

Stay safe, and thanks for the info!

 

[jmcalli2]

View attachment 607596View attachment 607597View attachment 607598View attachment 607599

These pics were sent to me in late December 2004-5 or so by my mentor and good friend. He was a retired USMC Captain with a Marine Corps sense of humor.

 

[XBe02Drvr]

That Syracuse GE facility, actually in Liverpool NY, is Lockheed-Martin now

GE Armament was sold to Lockheed-Martin sometime in the mid 90s.

I've been to Burlington a few times. Lovely town.

"Ithaca North"

One of my first jobs in the early 80s had me going around the SAC base at Griffiss AFB in Rome. B-52s and F-106s.

Got my A&P at Riverside School of Aeronautics in Marcy NY, just west of Utica and just inside the outer marker for the long runway at Griffiss. Frequent aluminum overcasts accompanied with seismic tremors and rolling thunder. If a 106 got a waveoff on final, he'd light his burner right over us for the go around. If a BUFF did same, we'd have a virtual earthquake. They were Ds, no whiny turbofans here!

BTW, Syracuse is 40 inches short of their usual snowfall for this time of year. The Lake Effect seems to have moved South about 70 miles; Binghamton is 28 inches above their usual snowfall right now.

I've been watching this on radar on my cellphone. Airmass flow seems to be more east-west nowadays with less NW-SE component than I remember. Watertown and Fort Drum are getting the snow dumps Syracuse and Utica used to get, and ELM, ITH, BGM are catching it from Lake Erie, which used to dump on the northern tier of PA. Used to do overnights in ITH. BTV on steroids, AND it has the renowned Moosewood Restaurant.

Worst thing about flying (commercial) out of SYR is they don't remember how to de-ice more than one plane at a time until mid January.

Some things are eternal.
Thanks for the stroll down Memory Lane. Stay safe!

 

[P-39 Expert]

As someone formerly in the Defense Industry, Casey is the person who produced the chart, and Robinson is the person who checked that the chart was drawn correctly from the data supplied. Drawing "checkers" sometimes find errors and it gets corrected when found, if the error is actual.

Hi P-39 Expert,

The chart is, in fact, pretty far off, regardless of weight. It was established more than 60 pages ago that the drag coefficient of the XP-39 as it was built and before being modified into the XP-39B, would not allow 390 mph at either 1,050 or 1,150 hp. This chart of what is certain to be projected performace will not resurrect the debate and result in a different analysis if the analysis is done correctly since it was done correctly the first time. Time doesn't change the outcome when the facts are correct.

Agree that the P-39C chart was a projection and not actual, but the attached P-39N chart was actual and it shows 390+mph at 15000ft. At a much heavier weight.

 

[jmcalli2]

GE Armament was sold to Lockheed-Martin sometime in the mid 90s.


"Ithaca North"


Got my A&P at Riverside School of Aeronautics in Marcy NY, just west of Utica and just inside the outer marker for the long runway at Griffiss. Frequent aluminum overcasts accompanied with seismic tremors and rolling thunder. If a 106 got a waveoff on final, he'd light his burner right over us for the go around. If a BUFF did same, we'd have a virtual earthquake. They were Ds, no whiny turbofans here!


I've been watching this on radar on my cellphone. Airmass flow seems to be more east-west nowadays with less NW-SE component than I remember. Watertown and Fort Drum are getting the snow dumps Syracuse and Utica used to get, and ELM, ITH, BGM are catching it from Lake Erie, which used to dump on the northern tier of PA. Used to do overnights in ITH. BTV on steroids, AND it has the renowned Moosewood Restaurant.

Some things are eternal.
Thanks for the stroll down Memory Lane. Stay safe!

Used to watch the B-52s do touch & goes when I drove a truck.
Also remember driving up around Gouverneur/Massena/Malone when the snow banks were higher than the telephone poles.
Here's a cute site for snow: GoldenSnowball.com

Once mourned '78 we drove (North of Rome or South of Oneonta, can't remember) by some unusual sights: first a F-80 upside down on a pylon about ten feet above the ground, then a F-89 the same way, then a F-84F, then a F-102 and finally a F-100. All were at least a mile apart in the middle of nowhere (we were killing time, taking the scenic route). Finally we saw an olive drab truck with a half dozen soldier types around it about 200 yards up a side road. We turned towards them to ask about the planes, but they energetically waved us off.

My guess is it was a radar test range of some sort. Why the planes were all mounted upside down I can't figure.

 

[GregP]

Hi P-39 Expert. You are comapring apples to orange.

The XP-39 had a V-1710-35 with a turbocharger unit. It was rated at 1,150 hp and 3,000 rpm @ 44" MAP at altitude. After the turbo was deleted, the V-1710-35 made 1,050 hp and 3,000 rpm @ 44" MAP at about 9,500 feet. It never hit 390 mph, ever, in level flight.

The P-39N had a V-1710-85 (E19) engine. It developed 1,410 hp at 3,000 rpm @ 57" MAP. Add 360+ hp to a 360 - 370 mph airplane and you will get a speed increase. The P-39N test on wwiiaircraftperformance shows 398.5 mph at 9,700 feet; 1,420 hp; 3,000 rpm, 59.8" MAP, which is war emergency power plus another 1.5" MAP; at 7,274 lbs. It had 9.6 : 1 supercharger gears, so the service celing was a bit lower than the 8.8 or 8.1 gear units. The -85 was really just a -83 engine driving through 2.23 : 1 reduction unit rather than the 2.00 : 1 unit the -83 used.

The P-39N was a very different animal than the XP-39 chart shown a few pages above, and it has decent performance. But, by then, the reputation of the P-39 had been established and pretty much nobody in the USAAF wanted it. Most went to the Soviet Union (4,746 P-39s in total) since they mostly got the P-39N and Q models. After being left exposed to winter and harsh conditions in Soviet Service, I seriously doubt many would get the same performance at the same power levels, but the Soviets were not much concerned with the engines since they didn't pay for them, so they likely COULD get the test performance and more at 75 - 80" MAP.

By that time, the U.S.A. wasn't really sending out new P-39 units to war. We were supplying replacement aircraft and trying to re-equip as was possible. Let's recall that the Pacific was not the theater of priority until Germany was defeated.

Bottom line: The performance of a shiny new P-39N does not mean the XP-39 suddenly got better.

 

[soulezoo]

Cool.

I just asked because I grew up in Syracuse, my Mom worked at GE making TVs in the '60s. That Syracuse GE facility, actually in Liverpool NY, is Lockheed-Martin now, recently got a big sonar contract. Could still be some GE there too.

I worked in the Albany area for a time, passed through the huge Schenectady GE campus there quite often.
Along with the Watervliet Arsenal, I drove past that about every day for a year. Interesting place.

I've been to Burlington a few times. Lovely town.

One of my first jobs in the early 80s had me going around the SAC base at Griffiss AFB in Rome. B-52s and F-106s. Saw a Navy T-2 Buckeye parked in front of the tower once. Very interesting place.

BTW, Syracuse is 40 inches short of their usual snowfall for this time of year. The Lake Effect seems to have moved South about 70 miles; Binghamton is 28 inches above their usual snowfall right now.

Worst thing about flying (commercial) out of SYR is they don't remember how to de-ice more than one plane at a time until mid January.

Stay safe, and thanks for the info!

I have family in Binghamton and can confirm about the snow.

 

[jmcalli2]

Hi P-39 Expert. You are comapring apples to orange.

The XP-39 had a V-1710-35 with a turbocharger unit. It was rated at 1,150 hp and 3,000 rpm @ 44" MAP at altitude. After the turbo was deleted, the V-1710-35 made 1,050 hp and 3,000 rpm @ 44" MAP at about 9,500 feet. It never hit 390 mph, ever, in level flight.

The P-39N had a V-1710-85 (E19) engine. It developed 1,410 hp at 3,000 rpm @ 57" MAP. Add 360+ hp to a 360 - 370 mph airplane and you will get a speed increase. The P-39N test on wwiiaircraftperformance shows 398.5 mph at 9,700 feet; 1,420 hp; 3,000 rpm, 59.8" MAP, which is war emergency power plus another 1.5" MAP; at 7,274 lbs. It had 9.6 : 1 supercharger gears, so the service celing was a bit lower than the 8.8 or 8.1 gear units. The -85 was really just a -83 engine driving through 2.23 : 1 reduction unit rather than the 2.00 : 1 unit the -83 used.

The P-39N was a very different animal than the XP-39 chart shown a few pages above, and it has decent performance. But, by then, the reputation of the P-39 had been established and pretty much nobody in the USAAF wanted it. Most went to the Soviet Union (4,746 P-39s in total) since they mostly got the P-39N and Q models. After being left exposed to winter and harsh conditions in Soviet Service, I seriously doubt many would get the same performance at the same power levels, but the Soviets were not much concerned with the engines since they didn't pay for them, so they likely COULD get the test performance and more at 75 - 80" MAP.

By that time, the U.S.A. wasn't really sending out new P-39 units to war. We were supplying replacement aircraft and trying to re-equip as was possible. Let's recall that the Pacific was not the theater of priority until Germany was defeated.

Bottom line: The performance of a shiny new P-39N does not mean the XP-39 suddenly got better.

Small point: the XP-39 didn't fly without the turbo, the XP-39B did.

You are correct about the Soviets not caring about the longevity of the engines; they saw training a replacement pilot as more expensive than replacing an engine.

For overboost, I refer to what the British did with the Mustang I & IA, found near the bottom of this page:

E-GEH-16

My guess would be the Soviets did pretty much the same thing with their P-39s.
I'd love to see the climb rate for a P-39N at 72" Hg of boost.

 

[jmcalli2]

I have family in Binghamton and can confirm about the snow.

Hope they're away from the rivers. Some springs those floods are brutal.

 

[jmcalli2]

A little more 'food for discussion.'

Note: there are typos in the report: paragraph B. 1. b. "P-39D" should read "P-38D;" in paragraph B. 3. e. "P-39D" should;d read P-39C." Reading the entire report makes this clear.

it is an interesting report.

 

[GregP]

Where did you find the typos?

 

[jmcalli2]

Where did you find the typos?

In the report.

When you read it, you'll see the ONLY P-38 was the P-38D model and the ONLY P-39 was the P-39C model. The paragraph B. 3. e. (P-39 vs Spitfire) also reverts to "P-39C" later in the paragraph, further illustrating the typo.

Paragraph B. 1. b. only makes sense if you change "P-39D" to "P-38D" given the context of the report.

 

[XBe02Drvr]

Once mourned '78 we drove (North of Rome

some unusual sights: first a F-80 upside down on a pylon about ten feet above the ground, then a F-89 the same way, then a F-84F, then a F-102 and finally a F-100. All were at least a mile apart in the middle of nowhere

Rome Air Development Center, based out of Griffis, had responsibility for evaluation of antenna radiation and reception patterns for communications and ECM equipment. You missed the best exhibit of them all, a B52 inverted on a pylon and its vertical stabilizer on a hilltop south of Griffis, right near the revolutionary war Oriskany battlefield site, but visible only from the air.

Also remember driving up around Gouverneur/Massena/Malone when the snow banks were higher than the telephone poles.

We used to do PLB, MSS, OGS, ART, and on to SYR, BGM, AVP, and EWR, then back again. On a low IFR heavy snow day, it was a serious workout. When we got back to PLB, it was on to BTV, then ALB or BOS for a long layover overnight. Well earned.

 

[SaparotRob]

Rome Air Development Center, based out of Griffis, had responsibility for evaluation of antenna radiation and reception patterns for communications and ECM equipment. You missed the best exhibit of them all, a B52 inverted on a pylon and its vertical stabilizer on a hilltop south of Griffis, right near a revolutionary war battlefield site, but visible only from the air.

We used to do PLB, MSS, OGS, ART, and on to SYR, BGM, AVP, and EWR, then back again. On a low IFR heavy snow day, it was a serious workout. When we got back to PLB, it was on to BTV, then ALB or BOS for a long layover overnight. Well earned.

I LOVE aviation gibberish!