Trade-offs in WWII Fighter Design

[M.B-5]

Huh?  Oh, I geddit, 'haze the newbie'... aww c'mon, jeeze...

 

Anyhow... this period 'Flight' article shows how the liquid-cooled engine still offered a superior installed power-to-weight ratio.

( Sabre versus R-2800).

 

http://www.flightglobal.com/pdfarchive/view/1946/1946 - 1443.html

 

[Meplat]

46 minutes ago, M.B-5 said:

 

 

 

& sleeve-valve engine oil-consumption was certainly better than the big US radials, with their loose clearances

plus a multitude - of leaky joints...

 

 

 

What radials have you worked on? Cause I'd put the worst wartime production Jacobs against a Bristol for oil consumption, let alone a P&W R2800..

 

 

[M.B-5]

Here are the Bristol Hercules consumption figures, they are fairly good, Meplat - can you post those for the R-2800?

 

http://www.flightglobal.com/pdfarchive/view/1946/1946 - 2242.html

[Meplat]

6 minutes ago, M.B-5 said:

Huh?  Oh, I geddit, 'haze the newbie'... aww c'mon, jeeze...

 

Anyhow... this period 'Flight' article shows how the liquid-cooled engine still offered a superior installed power-to-weight ratio.

( Sabre versus R-2800).

 

http://www.flightglobal.com/pdfarchive/view/1946/1946 - 1443.html

 

That's cute, but it's not saying where or when those mills are developing their power.

Also- 1946..  The -73 variant of the 2800 was reliably producing  1 hp per cube.  Not hard to find late R2800's producing 2500 HP with mild boost.

 

Also-

That article uses the P&W S1A4 variant, AKA "a dash five", which was meant for bomber use.

 

[Sturgeon]

16 minutes ago, M.B-5 said:

Huh?  Oh, I geddit, 'haze the newbie'... aww c'mon, jeeze...

 

 

???

 

I am asking you to follow the forum guidelines. Did you read them?

 

You've got to build a rapport with people before you go around nitpicking their shit. This is basic human interaction 101 stuff.

[M.B-5]

The final Sabre made 3,500hp for take-off - from 2238 CI, somewhat better than the R-2800's 1 per..

[Meplat]

2 minutes ago, M.B-5 said:

Here are the Bristol Hercules consumption figures, they are fairly good, Meplat - can you post those for the R-2800?

 

http://www.flightglobal.com/pdfarchive/view/1946/1946 - 2242.html

It's around 2 quarts/hour barring WEP/MAX op.

[Meplat]

1 minute ago, M.B-5 said:

The final Sabre made 3,500hp for take-off - from 2238 CI, somewhat better than the R-2800's 1 per..

Great, and by then it was thoroughly obsolete for fighter use. You are not going to stuff a late Sabre in an airliner when you can do the same work, more reliably, with a 2800 or a Herc.

 

 

 

 

 

[M.B-5]

9 minutes ago, Sturgeon said:

 

???

 

I am asking you to follow the forum guidelines. Did you read them?

 

You've got to build a rapport with people before you go around nitpicking their shit. This is basic human interaction 101 stuff.

 

That door swings both ways, does it not?

I was responding to his querying my apparent misapprehension - as it happens.

& do the 'guidelines' include a basic standard of language usage requirement?

[M.B-5]

4 minutes ago, Meplat said:

Great, and by then it was thoroughly obsolete for fighter use. You are not going to stuff a late Sabre in an airliner when you can do the same work, more reliably, with a 2800 or a Herc.

 

 

 

 

 

Actually, the RAF flew their Sabres, & flew them hard* - for 10 years post-war, so they can't have been all that bad...

 

* At power levels that would make an R-2800 wilt, from heat-soak, & need a lie down.

 

[Meplat]

1 minute ago, M.B-5 said:

Actually, the RAF flew their Sabres, & flew them hard* - for 10 years post-war, so they can't have been all that bad...

 

* At power levels that would make an R-2800 wilt, from heat-soak, & need a lie down.

 

And now you're whistling through the graveyard.

I worked on P&W and Wright radials that had been run hard for 50+ years. 

Much as I liked the tech of the Sabre, it is a museum piece, while the 2800 is still converting 100LL into "go", and likely will be for a while to come.

 

 

[M.B-5]

29 minutes ago, Meplat said:

It's around 2 quarts/hour barring WEP/MAX op.

 

J_G_T's kindly posted figures for the F4U's R-2800 - gives a max cruise oil consumption of 16 Qt/hr!

[Sturgeon]

25 minutes ago, M.B-5 said:

 

That door swings both ways, does it not?

 

Not really. This, as you might have noticed by the name, is my house.

[Meplat]

Just now, M.B-5 said:

 

J_G_T's kindly posted figures for the F4U's R-2800 - gives a max cruise oil consumption of 16 Qt/hr!

You're quoting max ALLOWABLE.  as in "it's leaking slower than we're pouring it in"

With a Corsair's 13 gallon oil tank, that would give the bird a three and a quarter hours of operation..

 

Be sensible now.

 

 

[M.B-5]

13 minutes ago, Meplat said:

And now you're whistling through the graveyard.

I worked on P&W and Wright radials that had been run hard for 50+ years. 

Much as I liked the tech of the Sabre, it is a museum piece, while the 2800 is still converting 100LL into "go", and likely will be for a while to come.

 

 

The thread is about WW2, era machines though, right?

 

However Kermit Weeks is in the process of restoring his super-rare Sabre-Tempest to fly,

& has a couple of NOS Sabres - on hand for it.

Mike Nixon reckons the Sabre is less complex than popularly supposed,

being more a case of multiplicity of parts, & is a "straightforward" engine to overhaul.

[M.B-5]

2 minutes ago, Sturgeon said:

 

Not really. This, as you might have noticed by the name, is my house.

Ok "D.J.T.", so you hold the ah, 'trump cards', I geddit,

& aint no sorry sucka caint beat the house, just like in Vegas...

[Meplat]

1 minute ago, M.B-5 said:

The thread is about WW2, era machines though, right?

 

However Kermit Weeks is in the process of restoring his super-rare Sabre-Tempest to fly,

& has a couple of NOS Sabres - on hand for it.

Mike Nixon reckons the Sabre is less complex than popularly supposed,

being more a case of multiplicity of parts, & is a "straightforward" engine to overhaul.

Nothing is straightforward about a sleeve valve mill. Go work on one and get back to me.

 

Just now, M.B-5 said:

Ok "D.J.T.", so you hold the ah, 'trump cards', I geddit,

& aint no sorry sucka caint beat the house, just like in Vegas...

 

When you stop being silly, I'll take you seriously.

A bit of advice though-"You're about to piss on the weedburner wire".

 

 

[Sturgeon]

1 minute ago, M.B-5 said:

Ok "D.J.T.", so you hold the ah, 'trump cards', I geddit,

& aint no sorry sucka caint beat the house, just like in Vegas...

 

Or you could just treat the oldfags on this forum with a little respect until you've earned some of theirs, yeah?

 

Literally, I am just asking you to not be obnoxious and follow the forum guidelines. This isn't a persecution, it's basic posting hygiene.

[M.B-5]

Yeah fair enough, boss - can/will do.

[M.B-5]

Meplat, with no moving parts above the piston, & many fewer parts overall than a poppet valve mill,

the sleeve valve is indeed quite "straightforward" by comparison,

& on the record, Kiwi Bristol mech/techs got 3,000hr TBOs from their Hercs..

[Meplat]

5 hours ago, M.B-5 said:

Meplat, with no moving parts above the piston, & many fewer parts overall than a poppet valve mill,

the sleeve valve is indeed quite "straightforward" by comparison,

& on the record, Kiwi Bristol mech/techs got 3,000hr TBOs from their Hercs..

Take this for what you will, but you really are coming across as someone who has never seen the inside of the mills in question.

You are getting a simpler looking top end, at the expense of a more complex cylinder, and a much more complex set of valve timing gears.

 

Are you really going to claim that the sleeve valve radial "is better" because you don't like how busy the top end of most radial engine look?

Please. That is patently ridiculous.

 

[Bronezhilet]

15 hours ago, Domus Acipenseris said:

No docs in this post, sorry.

 

The P-38 was designed as an interceptor.  As such, it was expected that the pilot could do things like switch fuel tanks, change prop pitch, and adjust the mixture at his leisure.  The main reason for the difference in combat performance between the PTO and ETO was the lack of an Integrated Air Defense System in the PTO.  Japanese interceptors were trying to climb up to reach the American strikes and the P-38's had the advantage in situational awareness and energy.  In the ETO the Germans had the edge in both due to their high quality (for the time) IADS.  The P-38's switchology was too difficult for the average pilot whereas the P-51 gave the pilot a better chance.  Other factors in the P-38's performance in the ETO were lack of experience and relative numbers.  The P-51 arrived when the US had more knowledge and more planes and the Germans had fewer.

 

The P-47 was a better fighter bomber than the P-51 due to greater range-payload and lower vulnerability.  The P-47 was capable of handling the German fighters but at $80,000 a piece vs $50,000 for a P-51 the P-47 had to be used where it was most effective.

 

 

The German IADS might have had better IADS than the Japs, but it had some serious, serious flaws. When the British intelligence figured them out, the whole Kammhuber Line came crashing down.

 

When I can find the time and energy I should make a topic about it, since it's quite an interesting subject.

[M.B-5]

5 hours ago, Meplat said:

Take this for what you will, but you really are coming across as someone who has never seen the inside of the mills in question.

You are getting a simpler looking top end, at the expense of a more complex cylinder, and a much more complex set of valve timing gears.

 

Are you really going to claim that the sleeve valve radial "is better" because you don't like how busy the top end of most radial engine look?

Please. That is patently ridiculous.

 

No.

Even as a kid, I was amazed to see the internal workings of the Hercules,

& again, to conflate multiplicity with complexity - is technically incorrect.

 

Please refer to Roy Fedden's list of patently revealed sleeve-valve merits, Meplat - to gain a "better" appraisal,

(as linked in the article below).

 

http://www.flightglobal.com/pdfarchive/view/1941/1941 - 2830.html

[M.B-5]

17 hours ago, Meplat said:

 

 

 

A blown/"Malcom Hood" would have contributed jack and/or shit to the performance/effectiveness of the P-38.

 

 

 Yet they sure did prove useful for the F4U & P-51 et al...

Lockheed didn't use the P-38's multi-framed canopy on their next fighter, the P-80, did they.

 

 

The USAAF deemed the P-38 as effectively passe`, & rather than 'polish the turd' - ordered the P-82, instead.

 

In fact, the USAAF had major concerns about the P-38's shortcomings as a fighter, in the intense combat ETO.

Summarized as:

 

"...airspeed limitations are low... ...tail buffeting... ...cause structural failure...

...definitely objectionable & hazardous.."

 

See full report here: http://www.wwiiaircraftperformance.org/p-38/p-38-67869.html

 

 

[Meplat]

23 minutes ago, M.B-5 said:

No.

Even as a kid, I was amazed to see the internal workings of the Hercules,

& again, to conflate multiplicity with complexity - is technically incorrect.

 

Please refer to Roy Fedden's list of patently revealed sleeve-valve merits, Meplat - to gain a "better" appraisal,

(as linked in the article below).

 

http://www.flightglobal.com/pdfarchive/view/1941/1941 - 2830.html

Ah hahaha! a magazine article that reads like a sales brochure!?

You HAVE to be fucking kidding me.

I may as well post a cigarette ad from the 40's saying how great Lucky Strikes are for my lungs.

 

Again, you don't know what the hell you're talking about.  You have a huge fucking battery of gears to keep a two row sleeve jug engine timed properly, if just one is put in wrong, that jug is out of time,

all you have for an "inferior" 2800 is two cam discs and two gears. That's it.  It's all but impossible to fuck up the valve timing .

Go look at diagrams of the interiors of both engines, and you'll immediately see where you fucked up in believing a  dual row sleeve valve engine is "simpler" because of some period spiel meant to sell engines.

 

Now, fucking blown hoods were put on the Corsair and Mustang to increase rearward visibility past the fuselage structure.

The  '38 did not need it, because it already had excellent all around visibility. It had no aft fuselage to obstruct rearward visibility to begin with.

Sticking a  full bubble canopy on a '38 would have given at best a minor improvement  in visibility, and no improvement in performance.

 

For fuck's sake man, Use your goddamn head as something other than an ear spacer.