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

[SaparotRob]

Is this the one where, when Daffy is being pursued by Hitler and Mussolini, puts a Stalin mask and terrifies the two?

 

[GrauGeist]

Is this the one where, when Daffy is being pursued by Hitler and Mussolini, puts a Stalin mask and terrifies the two?

I think that's the one where he's a commando and first confronts a raven who's a German officer wearing a monocle.

 

[SaparotRob]

No that's a different one. Commando Daffey? There was a smaller bird named Schultz who was always getting clobbered by the officer. It's been a long time since I've seen those. I think I'm going to look them up.

 

[buffnut453]

And another 3 pages have been added with no answer to my post #2746.

Sorry for such boring posts but I keep hoping to get an answer.

 

[SaparotRob]

It keeps us grounded.

 

[SaparotRob]

I think that's the one where he's a commando and first confronts a raven who's a German officer wearing a monocle.

I just looked it up. That's Daffey the Commando. His foil is Uberkomt von Vultur.
In Russian Rhapsody, it's 3 gremlins who put on the Stalin mask.
Best. Research. Ever.

 

[GregP]

Hey Buffnut, if he doesn't answer questions that put a bad light on either the P-39 or himself for being wrong, what makes you think he'll ever answer your request for a sources on the gas heater in a P-39D?

Doesn't really need an answer. I think we understand the lack of enthusiasm for a reply since perhaps there IS no source. On the other hand, perhaps he'll surprise us all and chime in with one. Still, it won't turn a sow's ear P-39 into silk purse fighter. All it can do is kill the pilot with carbon monoxide poisoning, and do it while being very heavy and sapping otherwise potential war winning performance, nose armor aside ... maybe even 498 mph .... nnaaahhhhhhh. It's a P-39, for crying out loud.

Maybe this will help:

I'm starting to like it better than the P-39. At least it's an honest airplane that won't tumble and roll and dig a big hole.

 

[buffnut453]

Hey Buffnut, if he doesn't answer questions that put a bad light on either the P-39 or himself for being wrong, what makes you think he'll ever answer your request for a sources on the gas heater in a P-39D?

Doesn't really need an answer. I think we understand the lack of enthusiasm for a reply since perhaps there IS no source. On the other hand, perhaps he'll surprise us all and chime in with one. Still, it won't turn a sow's ear P-39 into silk purse fighter. All it can do is kill the pilot with carbon monoxide poisoning, and do it while being very heavy and sapping otherwise potential war winning performance, nose armor aside ... maybe even 498 mph .... nnaaahhhhhhh. It's a P-39, for crying out loud.

Maybe this will help:

View attachment 633182

I'm starting to like it better than the P-39. At least it's an honest airplane that won't tumble and roll and dig a big hole.

Welcome to the dark side. Here...have a cookie!

 

[P-39 Expert]

I believe the British corrected performance to 95% of gross weight. Not tested at 95% gross weight, since the weight varied during a test flight.

Exactly what I have been saying, tested at gross weight but test weight listed as 95% of gross to approximate average fuel during the flight.

Thank you.

 

[P-39 Expert]

Hey Buffnut, if he doesn't answer questions that put a bad light on either the P-39 or himself for being wrong, what makes you think he'll ever answer your request for a sources on the gas heater in a P-39D?

Doesn't really need an answer. I think we understand the lack of enthusiasm for a reply since perhaps there IS no source. On the other hand, perhaps he'll surprise us all and chime in with one. Still, it won't turn a sow's ear P-39 into silk purse fighter. All it can do is kill the pilot with carbon monoxide poisoning, and do it while being very heavy and sapping otherwise potential war winning performance, nose armor aside ... maybe even 498 mph .... nnaaahhhhhhh. It's a P-39, for crying out loud.

Maybe this will help:

View attachment 633182

I'm starting to like it better than the P-39. At least it's an honest airplane that won't tumble and roll and dig a big hole.

What sources do you need? The pilot's manuals say the gas heater was in the export models (P-400, P-39D1 and D2) and the rest (D/F/K/L/M/N/Q) had the ducted air system.

 

[buffnut453]

What sources do you need? The pilot's manuals say the gas heater was in the export models (P-400, P-39D1 and D2) and the rest (D/F/K/L/M/N/Q) had the ducted air system.

And what about the P-39C? Pilot's Manual says that had the gas heater and it wasn't an export version.

 

[P-39 Expert]

No, you can't do it that way.

It doesn't take into account the different internal friction and supercharger drive requirements.

Please look at the manual again.


Power level.............................HP .......................rpm.......................altitude....................fuel per hour.......................HP/hr/gal
MIlitary...................................1125......................3000.......................15,500.......................138...........................................8.15
Max continuous.................1000........................2600.......................14,000.......................109..........................................9.19
Economical max..................750.......................2280.......................14,000..........................74..........................................10.13
Minimum cruising (R).......600.......................2190........................14,000..........................52.........................................11.53
Minimum cruising (L).......600.......................2190........................14,000..........................48..........................................12.5


Please note that in above examples from the manual that in all but the Minimum cruise (L) the mixture was set to rich. All but the Military rating were at the same altitude.

Now when the engine goes from 600hp at 2190rpm to 1000hp at 2600rpm we have a 19% increase in rpm, a 60 % increase in power to the prop and a 209%increase in fuel per hour burned or about a 25% increase in fuel burned per HP hour.



I will throw it back at you.

Explain where the energy needed to over come the changes in internal friction and energy needed to drive the supercharger at the higher speeds come from, please.
Until you can then you are the one who is incorrect.

Because the only difference in fuel consumption at 25000' is RPM. Throttle set at full, mixture at auto rich. No other changes except going from 2600rpm to 3000rpm. Your figures at 14000'-15000' have no relevance to fuel consumption at 25000'.

 

[Thumpalumpacus]

And another 3 pages have been added with no answer to my post #2746.

Sorry for such boring posts but I keep hoping to get an answer.

As I wrote in a song long ago, "Silence says so much."

 

[Thumpalumpacus]

It keeps us grounded.

Quit hogging all the puns, man!

 

[pbehn]

Exactly what I have been saying, tested at gross weight but test weight listed as 95% of gross to approximate average fuel during the flight.

Thank you.

The P-51 D ended up with 465 gallons of fuel 6 MGs with ammunition, enough oil for an 8 hr mission at least, tail warning radar etc, the D was slightly heavier and slower than the B/C but thats exactly what the client wanted, why do you keep quibbling about small weight differences?

 

[GrauGeist]

Because the only difference in fuel consumption at 25000' is RPM. Throttle set at full, mixture at auto rich. No other changes except going from 2600rpm to 3000rpm. Your figures at 14000'-15000' have no relevance to fuel consumption at 25000'.

Are these the settings you used when you flew it?

 

[buffnut453]

Are these the settings you used when you flew it?

Not in formation, that's for damn sure.

 

[Shortround6]

Because the only difference in fuel consumption at 25000' is RPM. Throttle set at full, mixture at auto rich. No other changes except going from 2600rpm to 3000rpm. Your figures at 14000'-15000' have no relevance to fuel consumption at 25000'.

Hmmm, the figures at 14000-15,000ft were ALL at full throttle, mixture set at auto rich. They do show a pattern. So will every other aircraft engine.

Don't tell me I am wrong, show me I am wrong. Tell me where the power to overcome the increased internal friction and the increased power to turn the supercharger comes from?

The figures from the mid teens show a 26.6 % increase in fuel consumption going from 2600rpm to 3000rpm for a 12.5% increase in power.

power at 25,000ft for an Allison with 9.60 supercharger gears and no RAM at 2600rpm was about 670hp. You want a10.4% to 15% increase in power for a 15% increase in fuel consumption. NO other aircraft engine I know of could do that.

 

[FLYBOYJ]

Because the only difference in fuel consumption at 25000' is RPM. Throttle set at full, mixture at auto rich. No other changes except going from 2600rpm to 3000rpm. Your figures at 14000'-15000' have no relevance to fuel consumption at 25000'.

Pixie Dust, unicorn poop or Groundhog mystical incantations

 

[SaparotRob]

Power is out from a lightning strike. No desktop. Glad I charged the phone.