Corsair and Hellcat in Europe
- Thread starter GregP
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P-39 Expert
Non-Expert
WEP was only available below critical altitude of 17,500', above that altitude all military power. Faster below 23000' and within 3mph at 26000'. Plotted speeds were taken from the same graph you furnished above. Outclimbed the Hellcat substantially at all altitudes. No disrespect to the Hellcat, best carrier plane of WWII. Period.....except you made one glaringly obvious mistake. The speed shown for the P-39N is while using war emergency power settings, not military, which is what the Hellcat was flying at in this particular chart. Plus did you happen to notice that the speed of the P-39N rapidly drops below that of the Hellcat as it approaches strategic bomber altitudes, and keeps on plummeting further from there? So much for the argument that the Airacobra would make a great escort fighter in the ETO!!!!!
http://www.wwiiaircraftperformance.org/P-39/P-39N_level-speeds.jpg
Never said the P-39 was a great escort fighter.
DarrenW
Staff Sergeant
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DarrenW
Staff Sergeant
How quickly we forget. We had a thread shutdown due to this same behavior.
DarrenW
Staff Sergeant
One would expect the P-39 to climb faster, as it was designed form the ground up as an interceptor, not a dogfighter like the F6F. By the way you can add roughly 300-400 fpm to the Hellcat's climb rate, up to maximum boost (60" Hg) critical altitude of roughly 18,000ft, just to make things line up correctly....
P-39 Expert
Non-Expert
Can't seem to find that graph in wwiiaircraftperformance.org, is it from somewhere else?
The -5 didn't enter service until June '44 after the heavy lifting had been done. P-39N was out of production by April '43.
DarrenW
Staff Sergeant
Don't say that to the soldiers, sailors, and airman who fought the bitter battles to come from mid '44 onwards (or their family members for that matter). You just might get a knuckle sandwich!
DarrenW
Staff Sergeant
So there's actually something that you didn't already know and haven't seen concerning WWII aircraft. Interesting....
DarrenW
Staff Sergeant
And you're just deflecting the main topic now because you have been roundly defeated by a host of well-schooled and dedicated aviation historians who spent a lifetime learning their "trade". They just didn't read Jane's one time and called it a day. To really know this stuff you need multiple sources.
parsifal
Colonel
You guys should cut out the sniping unless you actually want the thread shut down. Respect each others different viewpoints, even if you don't agree with them.
DarrenW
Staff Sergeant
I'll do my part. Thanks for stepping in and trying to mediate the situation. At the end of the day this is just a hobby for me and not worth going fist to cuffs over anything that's discussed here..
Shortround6
Major General
Jane's as a source is highly variable. A lot depends on the year, sometimes the editor, and if peacetime orwartime. Civilian or military aircraft.
Government censorship. And sometime propaganda.
As an example the listing for the B-17 in a reprint edition putout in 1989 of the 1946/47 edition the weights of the B-17 are given as.
Empty 32,780lb
Normal loaded 49,500lbs
maximum overload 60,000lbs.
The description of the guns is for a "G" model.
The Manual for the "F"
has a basic weight of between 39,800lbs and 41,300lbs (basic weight includes crew, guns, ammo, oil and some misc. while empty does not.
However the loaded weights for 7 different conditions vary from 51,700lbs for basic weight plus 1732 gallons of fuel and no bombs) to 65,000lbs for 3 of the 7 load conditions. that is 5,000lbs more than Janes says for the heavier/later G.
From this we are left with two choices, 1, somebody spent a lot time faking a manual and putting it into distribution. 2. Jane's, quite possible due to war time restrictions and shortage of staff immediately post war, is in error.
Which is more likely?
Government censorship. And sometime propaganda.
As an example the listing for the B-17 in a reprint edition putout in 1989 of the 1946/47 edition the weights of the B-17 are given as.
Empty 32,780lb
Normal loaded 49,500lbs
maximum overload 60,000lbs.
The description of the guns is for a "G" model.
The Manual for the "F"
has a basic weight of between 39,800lbs and 41,300lbs (basic weight includes crew, guns, ammo, oil and some misc. while empty does not.
However the loaded weights for 7 different conditions vary from 51,700lbs for basic weight plus 1732 gallons of fuel and no bombs) to 65,000lbs for 3 of the 7 load conditions. that is 5,000lbs more than Janes says for the heavier/later G.
From this we are left with two choices, 1, somebody spent a lot time faking a manual and putting it into distribution. 2. Jane's, quite possible due to war time restrictions and shortage of staff immediately post war, is in error.
Which is more likely?
DarrenW
Staff Sergeant
Of course this is a rhetorical question, but something that should be considered when deciding to use secondary source material to support your claims.
By the way excellent sleuth work SR6.....
P-39 Expert
Non-Expert
Would still be interested in the source of your red line numbers on the -5. Is that from wwiiaircraft, or somewhere else?Of course this is a rhetorical question, but something that should be considered when deciding to use secondary source material to support your claims.
By the way excellent sleuth work SR6.....
Janes was only used for the cruising speeds of the B-24 and B-17. I'll throw it away today.
Shortround6
Major General
Janes can be useful, you just have to be careful and you have to not misapply information.
You come here and try to upset notions or ideas that many people have had for a long time.
If you have new facts that is OK.
But so far you have simply brought your own idea's on how things worked with very little to back them up.
Jane's may be right in a strict technical sense
"Normal Range with (max bomb load normal fuel) 1100miles (1,760km) at 220mph (352kmh) at 25,000ft (7,625m).
But they aren't really telling us what bomb pad really is or what normal fuel was. (1700 gal is listed in the description) and again.
Speed/ range of an individual aircraft is different that the speed/range of aircraft flying in a small formation which is different than speed/range flying in a large formation.
The manual that the link was provided for has 8 different speed/range charts with different loads and speeds. But again, that is an aircraft manual, not a operational planning chart or manual. It gives performance for individual aircraft and not groups.
You come here and try to upset notions or ideas that many people have had for a long time.
If you have new facts that is OK.
But so far you have simply brought your own idea's on how things worked with very little to back them up.
Jane's may be right in a strict technical sense
"Normal Range with (max bomb load normal fuel) 1100miles (1,760km) at 220mph (352kmh) at 25,000ft (7,625m).
But they aren't really telling us what bomb pad really is or what normal fuel was. (1700 gal is listed in the description) and again.
Speed/ range of an individual aircraft is different that the speed/range of aircraft flying in a small formation which is different than speed/range flying in a large formation.
The manual that the link was provided for has 8 different speed/range charts with different loads and speeds. But again, that is an aircraft manual, not a operational planning chart or manual. It gives performance for individual aircraft and not groups.
P-39 Expert
Non-Expert
Still would like to see your source for these speeds, looked all through the Hellcat section of wwiiaircraft. Could you show me please? Thanks.
P-39 Expert
Non-Expert
All I wanted to know was the cruising speed of a B-17. Janes said 220mph. If you think it is different then please supply your number. I'll use that. Thanks for your help.
Shortround6
Major General
Simple questions get simple answers, but not always the right ones.
The link to the manual was provided and there are plenty of B-17 manuals here;
Manual Index - American
How about doing your own work.
Glider
Captain
This seems to give a cruising speed of between 190 and 230 mph depending on power setting
http://www.wwiiaircraftperformance.org/B-17/Fortress_III_Data_Sheet.pdf
http://www.wwiiaircraftperformance.org/B-17/Fortress_III_Data_Sheet.pdf
Shortround6
Major General
Correct, but that is the speed for a single aircraft.
Now put 3 dozen in formation, fly at 220mph and then have the formation do a 45 degree turn. Guys on the inside have no trouble. They throttle back to 210 or 200 or 195 or whatever they have to do to keep station as the rest of the formation flys a bigger arc to the make the turn.
It is the guys on the outside of the turn that have trouble,if using the power setting for 230mph doesn't allow them to keep station they have to advance the throttles into the rich mixture position and suck down a lot more fuel per minute. Not a big deal for one or two turns but combined with throttle jockeying that goes on with trying to keep a large formation together in close proximity and ranges/speeds take beating compared to single aircraft performance.
Formation speed is governed by the worst performing plane in the group being in the worst position. Any other planning leads to stragglers which become losses.
