Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)

[FLYBOYJ]

The 20gal on the Flight Operations Instruction Chart is correct. It is an allowance. And it assumes climb to higher altitude starts at 5000' having traveled zero miles. This is being conservative since at least as soon as gear/flaps are up and climb speed is attained after form up the pilot will vector toward target. Then another 4.5min climbing to 5000' toward the target means an extra 13mi not included in calculations.

And it conflicts with part of the flight manual - Depending on how you fly its off by 6 gallons. This is about climb, not miles flown. Do you know what Vx and Vy is???

Yes fuel will be burned climbing from 5000' to 25000' but 73mi range will be gained by climbing at 170mphIAS (220mphTAS average) for 20minutes in the direction of the target. One more time, this has all been factored into the range calculations for every altitude and every power setting. Take any amount of fuel available at any altitude at any power setting (RPM/manifold pressure) and do the math. Available fuel divided by gallons per hour x TAS is always more than the range figure quoted. The very smart AAF officers who put together these charts accounted for the fuel burned/miles gained by climbing from 5000' to whatever altitude is chosen. They did this to lessen pilot workload and get all the range information on one chart. You don't need the Takeoff, Climb and Landing Chart for any range calculations.

Again at what rate of climb?? What RPM??? VX or VY???? Those AAF offices were smart for the most part but got a lot wrong that has been clearly pointed out

But I thought that previously you couldn't find any mention of any reserve for landing anywhere. Now we need 30minutes (you would use 45) to find our home field. That hasn't moved. I have always heard that the AAF used 20min.

You hear WRONG. 30 minutes is normal, 45 for IFR, the navy used 60. Did yo hear that from a gaming site?

Or maybe you have been in your pixie dust, unicorn poop or mystical incantations again. I just use the appropriate flight manual.

I'm not the one who has made outrageous claims on here and been proven wrong by a host of people on this forum with years of aviation experience.

When are you going to do Bill's flight plan? When are you going to show us actually flight planning you have done? When are you going to show up your aviation resume? When are you going to answer poor Buffnut!

 

[FLYBOYJ]

Yes, the P-38 was a twin meaning that two engines must be started (separately) and two sets of propeller and mag checks must be undertaken (separately).

No kidding! I never knew that! How many mag checks have you done????

 

[pbehn]

Take any amount of fuel available at any altitude at any power setting (RPM/manifold pressure) and do the math.

Why dont you show us some math! On ram pressure, superchargers, compression and combustion, flame fronts mean effective pressure, propeller efficiency, lift drag. You could also try to explain how a plane becomes more economical as it gets closer to dropping out of the sky?

All you do is take numbers from a manual that are guidelines or wrong and multiply or divide them.

 

[pbehn]

Yes, the P-38 was a twin meaning that two engines must be started (separately) and two sets of propeller and mag checks must be undertaken (separately).

Thats worth 400 miles of fuel in a P-39. No wonder the P-38 wasnt produced much.

 

[DerAdlerIstGelandet]

You don't need the Takeoff, Climb and Landing Chart for any range calculations.

Now I am convinced we are being trolled.

Or maybe you have been in your pixie dust, unicorn poop or mystical incantations again. I just use the appropriate flight manual.

Am I reading this right? Did you really just say this?

 

[P-39 Expert]

And it conflicts with part of the flight manual - Depending on how you fly its off my 6 gallons. This is about climb, not miles flown. Do you know what Vx and Vy is???

No conflict, the 20gal is an allowance on the range chart. It ties into the rest of the numbers on the chart. The 26gal is a measurement on the takeoff, climb and landing chart. It has nothing to do with computing range. Everything you need for computing range is on the range chart.

Again at what rate of climb?? What RMP??? VX or VY???? Those AAF offices were smart for the most part but got a lot wrong that has been clearly pointed out

I clearly pointed out that climb speed for the P-39N was 170mphIAS. The average altitude between 5000' and 25000' is 15000'. 170mphIAS at 15000' is 220mphTAS. I said all of that.

You hear WRONG. 30 minutes is normal, 45 for IFR, the navy used 60. Did yo hear that from a gaming site?

I was wrong? A few pages ago you had never heard of a landing reserve and couldn't find it quoted anywhere. I was the one that told you the USN used a 60min reserve to find an aircraft carrier maneuvering in the open ocean. Now you are the expert on landing reserve?

I'm not the one who has made outrageous claims on here and been proven wrong by a host of people on this forum with years of aviation experience.

There's a host if items that I have been proven correct. You have not proven me wrong on this range chart subject yet and I suspect that you won't.

When are you going to do Bill's flight plan? When are you going to show us actually flight planning you have done? When are you going to show up your aviation resume? When are you going to answer poor Buffnut!

I'm not a pilot but I have read the pilot manuals. If you have to be correct on every subject just because you are a pilot then the rest of us should just give up? Bill can compute his own crazy flight plan. I have computed numerous flight plans on here for the P-39 and the P-47 and the information comes straight from the manuals. Poor Buffnut. He's so concerned about the type of cabin heat on the P-39C when only 20 examples were completed and none saw combat. 20 examples. And I have explained on more than one occasion which models had the gas heater and which models had ducted air heat.

 

[P-39 Expert]

Why dont you show us some math! On ram pressure, superchargers, compression and combustion, flame fronts mean effective pressure, propeller efficiency, lift drag. You could also try to explain how a plane becomes more economical as it gets closer to dropping out of the sky?

All you do is take numbers from a manual that are guidelines or wrong and multiply or divide them.

I have shown you the math on every single example. The available fuel, altitude, gallons per hour and IAS/TAS are straight from the manuals.

 

[buffnut453]

Poor Buffnut. He's so concerned about the type of cabin heat on the P-39C when only 20 examples were completed and none saw combat. 20 examples. And I have explained on more than one occasion which models had the gas heater and which models had ducted air heat.

No you haven't explained. You keep stating that the export models had the gas heater while D variants onwards had ducted air. The number of P-39Cs produced is entirely irrelevant. It's simply a fact that it was a production airframe. I suspect that you keep equivocating on the topic because you clearly understand the thrust of my argument. You keep asserting that the dastardly Brits specified the unnecessary gas heater in a deliberate attempt to increase the weight of the P-400. The key flaw in this entire ridiculous argument is the timing of these events.

The British ordered the P-400 in late-1940. That was before the P-39C's first flight. Since the C variant also had the gas heater, it makes perfect sense that the same installation would be offered to the British as standard equipment for the type.

Furthermore, in order for the British to specify an extra and superfluous gas heater in late 1940 to deliberately make the P-400 overweight, it would mean they were attempting to sabotage the entire programme before any production P-39 variant had flown. Aside from requiring some real crystal ball gazing, why didn't they just not order the damn things and be done with it? Why go through the pain of deliberately ordering too much equipment on an aircraft that they'd already decided was useless before it was flown? That makes absolutely ZERO sense.

I really couldn't give two hoots about the various heaters in the P-39 variants. I do object when people trot out complete bullshit and refuse to acknowledge any evidence that contradicts it.

Looking forward to hearing how you try and dodge out of this latest information that flies in the face of your conspiracy theory.

 

[pbehn]

I have shown you the math on every single example. The available fuel, altitude, gallons per hour and IAS/TAS are straight from the manuals.

So you maintain that fuel economy increases with speed and altitude? Regardless of how many thousand feet you are above rated altitude and that the most economical altitude is where max speed, stall speed and cruise are the same? Have you any figures let alone a manual number for a P-39 at 30,000ft after dropping a 110gal tank at 25,000ft and climbing there? It is a fantasy nonsense scenario that defies physics, flight tests, everything I have ever read about flight and my whole life experience working with engines from mopeds through racing bikes to 5 litre V8s going across Saudi Arabia.

 

[buffnut453]

I have shown you the math on every single example. The available fuel, altitude, gallons per hour and IAS/TAS are straight from the manuals.

Just because you can add numbers doesn't mean you're using the right equations. You have qualified, experienced pilots here telling you that your math is incorrect. You're just refusing to listen. I suggest you go back to flight sim or other fanboy forums 'cos your nonsense is getting really old.

 

[GrauGeist]

I'm not a pilot but I have read the pilot manuals

This is pure gold...

 

[Thumpalumpacus]

This is pure gold...

"I'm not a doctor, but I play one on TV ..."

 

[Thumpalumpacus]

When are you going to do Bill's flight plan? When are you going to show us actually flight planning you have done? When are you going to show up your aviation resume? When are you going to answer poor Buffnut!

As we say in the pool-halls down here: quit talkin' and start chalkin'.

 

[P-39 Expert]

No you haven't explained. You keep stating that the export models had the gas heater while D variants onwards had ducted air. The number of P-39Cs produced is entirely irrelevant. It's simply a fact that it was a production airframe. I suspect that you keep equivocating on the topic because you clearly understand the thrust of my argument. You keep asserting that the dastardly Brits specified the unnecessary gas heater in a deliberate attempt to increase the weight of the P-400. The key flaw in this entire ridiculous argument is the timing of these events.

The British ordered the P-400 in late-1940. That was before the P-39C's first flight. Since the C variant also had the gas heater, it makes perfect sense that the same installation would be offered to the British as standard equipment for the type.

Furthermore, in order for the British to specify an extra and superfluous gas heater in late 1940 to deliberately make the P-400 overweight, it would mean they were attempting to sabotage the entire programme before any production P-39 variant had flown. Aside from requiring some real crystal ball gazing, why didn't they just not order the damn things and be done with it? Why go through the pain of deliberately ordering too much equipment on an aircraft that they'd already decided was useless before it was flown? That makes absolutely ZERO sense.

I really couldn't give two hoots about the various heaters in the P-39 variants. I do object when people trot out complete bullshit and refuse to acknowledge any evidence that contradicts it.

Looking forward to hearing how you try and dodge out of this latest information that flies in the face of your conspiracy theory.

Did the gas heater have weight? Yes. Was it necessary? No. Did the British order it on the P-400? Yes. Was it on any P-39 model not produced for export? No. Except the P-39C of which only 20 examples were produced. Gas heater on export models P-400, P-39D1 and P-39D2. No gas heater for domestic models P-39D/F/K/L/M/N/Q. Is this clear enough? Am I dodging your question in any way? This is about the 4th time I have explained this to you.

 

[pbehn]

Did the gas heater have weight? Yes. Was it necessary? No. Did the British order it on the P-400? Yes. Was it on any P-39 model not produced for export? No. Except the P-39C of which only 20 examples were produced. Gas heater on export models P-400, P-39D1 and P-39D2. No gas heater for domestic models P-39D/F/K/L/M/N/Q. Is this clear enough? Am I dodging your question in any way? This is about the 4th time I have explained this to you.

Bell told the British that this BS aeroplane had a ceiling of 36,000ft so it needs a heater for the pilot and the guns, as you have been told NAA put the same heater in the Mustang I without protest for the same reason. BTW the USA wasnt at war at the time, was it?

 

[buffnut453]

Did the gas heater have weight? Yes. Was it necessary? No. Did the British order it on the P-400? Yes. Was it on any P-39 model not produced for export? No. Except the P-39C of which only 20 examples were produced. Gas heater on export models P-400, P-39D1 and P-39D2. No gas heater for domestic models P-39D/F/K/L/M/N/Q. Is this clear enough? Am I dodging your question in any way? This is about the 4th time I have explained this to you.

Why was the heater unnecessary? If the P-39C didn't have the ducted air heating then removing the gas heater means you're producing an aircraft without any form of cockpit heating. Even by 1941 standards, that would be poor. And that ignores the glaringly obvious fact that the USAAF and Bell both thought the gas heater was necessary for the P-39C.

Take a look at the timeline and please explain how and why the Brits would deliberately put too much weight into an aircraft that hadn't yet flown and then continue with the order? It would be much easier to just cancel the order before any metal was cut. They had the time to do exactly that...but they didn't. Why?

Stop your senseless criticism of the Brits which has ZERO basis in fact, in timeline, or in any records so far put forward. Indeed, the Brits accepted the P-400 AFTER a specially cleaned up airframe came within 1% of the minimum performance requirements. In other words, they still went ahead and paid Bell even though the P-400 FAILED TO MEET ITS PERFORMANCE SPECS.

 

[buffnut453]

Bell told the British that this BS aeroplane had a ceiling of 36,000ft so it needs a heater for the pilot and the guns, as you have been told NAA put the same heater in the Mustang I without protest for the same reason. BTW the USA wasnt at war at the time, was it?

I think your first point there is the crux of the matter. The Brits ordered the P-400 before any operational variant P-39 had flown. We have no idea what performance claims were made by Bell, although the chart provided earlier in this thread gives some indication that the pre-1941 performance estimates were ridiculously optimistic. Rather than the Brits deliberately besmirching the good name of Bell, it seems far more likely that Bell sold the Brits a bill of goods....and then failed to deliver on it.

 

[pbehn]

I think your first point there is the crux of the matter. The Brits ordered the P-400 before any operational variant P-39 had flown. We have no idea what performance claims were made by Bell, although the chart provided earlier in this thread gives some indication that the pre-1941 performance estimates were ridiculously optimistic. Rather than the Brits deliberately besmirching the good name of Bell, it seems far more likely that Bell sold the Brits a bill of goods....and then failed to deliver on it.

Bell didnt do anything to tell the RAF that their estimates were way off. Supermarine almost lost the contract for Spitfires because of low levels of production between 1936 and 38, a part of this was the difficulty of producing wings, but within that as soon as the first models were tested the wings had to be changed to incorporate ducted heating. If the guns dont work the aeroplane is FFFing useless, a danger to its pilot and everyone that depends on it up to Churchill himself. I cant accept this being treated as a petty issue by the expert, it wasnt, and no requirement was placed on Bell that wasnt placed on everyone else. In fact I would go as far as saying gun heating on USA aircraft was something learned by the USA from British or others specifications, Bell were just behind the curve as usual.

 

[Shortround6]

I do like the way the P-39 "escorts" clear the airfield fence, get the gear up, switch to the drop tank and head for Germany.

at some point in 1943 the P-47 groups changed number of aircraft per squadron to 25 aircraft. Or 75 planes for a 3 squadron group. even if not all planes are flying let's call it 50 planes operational on a given day. At 15 seconds between planes that is 12.5 minutes, at 20 seconds between planes that 16.7 minutes.

Using the "experts" flight plan the lead plane/s are at about 15,000ft and 50 miles from the airfield when the last plane/s take off.
This is actually brilliant planning as we don't have to worry about the fuel used in formation flying. There is NO formation. Just a bunch of planes in ones (mostly) and twos (occasionally) strung out over 50 miles winging their way into enemy airspace.

I also like the way he picks which parts of the manuals (or which sentences ) he is going to use and which he is going to ignore.

 

[FLYBOYJ]

No conflict, the 20gal is an allowance on the range chart. It ties into the rest of the numbers on the chart. The 26gal is a measurement on the takeoff, climb and landing chart. It has nothing to do with computing range. Everything you need for computing range is on the range chart.

YES IT IS A CONFLICT!

And if you had any kind of aviation or flight training besides what you read while relaxing in your lounge chair you would recognize this!

The only thing the climb chart and landing and take off charts have in common is they are printed on the same page, again, something that a novice wouldn't understand!

I clearly pointed out that climb speed for the P-39N was 170mphIAS. The average altitude between 5000' and 25000' is 15000'. 170mphIAS at 15000' is 220mphTAS. I said all of that.

OK ... and???

I was wrong? A few pages ago you had never heard of a landing reserve and couldn't find it quoted anywhere. I was the one that told you the USN used a 60min reserve to find an aircraft carrier maneuvering in the open ocean. Now you are the expert on landing reserve?

The reserve you are attempting to explain is an extended flight reserve just in case you get lost or have to deviate. It is there to make it to your destination. Again, your terminology as a novice further shows your lack of understanding. And yes I AM AN EXPERT ON FLYING WITH A FUEL RESERVE! I'VE DONE IT! HAVE YOU????

There's a host if items that I have been proven correct. You have not proven me wrong on this range chart subject yet and I suspect that you won't.

I have but you're too much of a narcissist to admit when you're wrong, not only to me but to many other members on this forum!

I'm not a pilot but I have read the pilot manuals.

We can definitely see that! I guess I can read manuals about brain surgery too!

If you have to be correct on every subject just because you are a pilot then the rest of us should just give up?

Rest of "us"?? No, but maybe YOU should! I think it's "YOU" vs. "the rest of us!" There have been many well versed members on this forum who have proven me wrong many times (some of them "non-pilots") and when I see the evidence in front of me I take it as a learning experience, something that I've made a point to do when I first started in aviation over 40 years ago, but I think it's almost comical when you have 5 or 6 members coming up with the same conclusions who actually flown aircraft or worked in the industry attempting to show you the errors in your ways and you refuse to listen! But then again, you're NOT a pilot but read the manuals!

Bill can compute his own crazy flight plan. I have computed numerous flight plans on here for the P-39 and the P-47 and the information comes straight from the manuals.

And probably half of what you're computed is in error because despite "reading the manuals" you don't have the training or background to fully grasp what you're looking at!

Poor Buffnut. He's so concerned about the type of cabin heat on the P-39C when only 20 examples were completed and none saw combat. 20 examples. And I have explained on more than one occasion which models had the gas heater and which models had ducted air heat.

First time I'm hearing it!

"I'm not a pilot but I have read the pilot manuals."