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View Full Version : Performance data for P-40, etc, and octane?



XyZspineZyX
08-29-2003, 09:40 AM
Something that struck me last night - the P-40
seems to be underperforming in terms of speed
relative to US test figures, and Huckebein_FW
mentioned that in USSR service the P-63 failed
to achieve rated speed. I am wondering if this
is because of the lower octane fuel typically
used by the USSR. If Oleg is using Soviet test
data for performance, it might be that the speed
achieved for the P-40 is accurate for that lower
octane fuel.

What might be nice is to have the option of
selecting different octane fuels, with corresponding
performance differences. This would allow, online,
or in offline missions, fuel quality to be restricted
to the historical levels prevalent in various theatres.

XyZspineZyX
08-29-2003, 09:40 AM
Something that struck me last night - the P-40
seems to be underperforming in terms of speed
relative to US test figures, and Huckebein_FW
mentioned that in USSR service the P-63 failed
to achieve rated speed. I am wondering if this
is because of the lower octane fuel typically
used by the USSR. If Oleg is using Soviet test
data for performance, it might be that the speed
achieved for the P-40 is accurate for that lower
octane fuel.

What might be nice is to have the option of
selecting different octane fuels, with corresponding
performance differences. This would allow, online,
or in offline missions, fuel quality to be restricted
to the historical levels prevalent in various theatres.

XyZspineZyX
08-29-2003, 10:22 AM
That would be an interesting option. I'm also of the understanding that the German engines had to operate on several different grades of fuel as well, giving lower performance for lower grades, but in the game all of them are currently modeled with the highest fuel grade the LW used.

Being able to actually use the different fuel grades would certainly make the online wars interesting. Fuel dumps suddenly become extremely importaint.

Harry Voayger

http://groups.msn.com/_Secure/0YQDLAswcqmIpvWP9dLzZVayPXOmo6IJ16aURujNfs4dDETH84 Q6eIkCbWQemjqF6O8ZfvzlsvUUauJyy9GYnKM6!o3fu!kBnWVh BgMt3q2T3BUQ8yjBBqECLxFaqXVV5U2kWiSIlq1s6VoaVvRqBy Q/Avatar%202%20500x500%20[final).jpg?dc=4675409848259594077

michapma
08-29-2003, 10:35 AM
According to my lovely P-40 pilot's handbook, the P-40 types ran on Grade 100 "gasoline". It could, however, be run without problems (so long as you respected the operating limits) on Grade 91. Unfortunately I have no idea about the fuel available on the eastern side of the Eastern Front. If you are interested, I can make some charts available for both fuel grades for the P-40 Allison (and Rolls-Royce) engine.

Mike

<table width="100%" border="0" cellspacing="0" cellpadding="10"><tr valign="middle" bgcolor="#3e463b"><td height="40" colspan="3" align="center">The ongoing IL-2 User's Guide project (http://people.ee.ethz.ch/~chapman/il2guide/)</a></td></tr><tr bgcolor="#515e2f"><td width="40%">FB engine management:
Manifold Pressure sucks (http://www.avweb.com/news/columns/182081-1.html)
Those Marvelous Props (http://www.avweb.com/news/columns/182082-1.html)
Mixture Magic (http://www.avweb.com/news/columns/182084-1.html)
Putting It All Together (http://www.avweb.com/news/columns/182085-1.html)
Those Fire-Breathing Turbos (Part 1 of 6) (http://www.avweb.com/news/columns/182102-1.html)</td><td align="center">

‚ =69.GIAP=Chap‚

69.GIAP (http://www.baseclass.modulweb.dk/giap/)</p></td><td width="40%" align="right" valign="top">Hardware:
Flight Simulation Performance Analyzed (http://www.simhq.com/_air/air_062a.html)
Building a home-made throttle quadrant step by step (http://forums.ubi.com/messages/message_view-topic.asp?name=us_il2sturmovik_gd&id=zkavv)
Sound Can Be Hazardous for Games (http://www6.tomshardware.com/game/20030405/index.html)</td></tr></table>

XyZspineZyX
08-29-2003, 12:55 PM
michapma wrote:
- According to my lovely P-40 pilot's handbook, the
- P-40 types ran on Grade 100 "gasoline". It could,
- however, be run without problems (so long as you
- respected the operating limits) on Grade 91.

What was the relative output on grade 91, though?
The same, lower?

XyZspineZyX
08-29-2003, 01:24 PM
AaronGT wrote:
-
- michapma wrote:
-- According to my lovely P-40 pilot's handbook, the
-- P-40 types ran on Grade 100 "gasoline". It could,
-- however, be run without problems (so long as you
-- respected the operating limits) on Grade 91.
-
- What was the relative output on grade 91, though?
- The same, lower?


The same, though engines worn out faster.
But you have to remember that soviet units also received american fuel for american planes.


<center> http://www.stormbirds.com/images/discussion-main.jpg </center>

XyZspineZyX
08-29-2003, 01:29 PM
And the reason why P-63 can't achieve 380mph is purely aerodynamic, at 350mph thrust is below drag (drag calculated with the best value for Cd0 - 0.018)


<center> http://www.stormbirds.com/images/discussion-main.jpg </center>

XyZspineZyX
08-29-2003, 01:34 PM
Huckebein_FW wrote:
- And the reason why P-63 can't achieve 380mph is
- purely aerodynamic, at 350mph thrust is below drag
- (drag calculated with the best value for Cd0 -
- 0.018)

LOL!

<ceter>http://www.dalnet.se/~surfcity/swedish_aviators/images/whirlwind_1.jpg </center>
Ralph H√¬§ggberg one of 5 Swedish
pilots flying for the RAF

michapma
08-29-2003, 01:39 PM
Okay, you made me do it. /i/smilies/16x16_robot-happy.gif

There were recommended operating limits, according to the POH.



http://people.ee.ethz.ch/~chapman/flightsims/images/p-40/poh_page45.jpg



http://people.ee.ethz.ch/~chapman/flightsims/images/p-40/poh_page46.jpg



http://people.ee.ethz.ch/~chapman/flightsims/images/p-40/poh_page47.jpg



http://people.ee.ethz.ch/~chapman/flightsims/images/p-40/poh_page48.jpg


<table width="100%" border="0" cellspacing="0" cellpadding="10"><tr valign="middle" bgcolor="#3e463b"><td height="40" colspan="3" align="center">The ongoing IL-2 User's Guide project (http://people.ee.ethz.ch/~chapman/il2guide/)</a></td></tr><tr bgcolor="#515e2f"><td width="40%">FB engine management:
Manifold Pressure sucks (http://www.avweb.com/news/columns/182081-1.html)
Those Marvelous Props (http://www.avweb.com/news/columns/182082-1.html)
Mixture Magic (http://www.avweb.com/news/columns/182084-1.html)
Putting It All Together (http://www.avweb.com/news/columns/182085-1.html)
Those Fire-Breathing Turbos (Part 1 of 6) (http://www.avweb.com/news/columns/182102-1.html)</td><td align="center">

‚ =69.GIAP=Chap‚

69.GIAP (http://www.baseclass.modulweb.dk/giap/)</p></td><td width="40%" align="right" valign="top">Hardware:
Flight Simulation Performance Analyzed (http://www.simhq.com/_air/air_062a.html)
Building a home-made throttle quadrant step by step (http://forums.ubi.com/messages/message_view-topic.asp?name=us_il2sturmovik_gd&id=zkavv)
Sound Can Be Hazardous for Games (http://www6.tomshardware.com/game/20030405/index.html)</td></tr></table>

XyZspineZyX
08-29-2003, 01:40 PM
Ah I remember now better, P-39 in russian service when flown with russian fuel had a wire on the throttle to hinder the pilot to select WEP. But this wire could be broken in emergencies. Also P-40 engine could not achieve the WEP boost of P39. So I doubt that there were any restrictions for P40 with russian fuel.


<center> http://www.stormbirds.com/images/discussion-main.jpg </center>

michapma
08-29-2003, 01:48 PM
You are generalizing. Don't step on HarryVoyager's vision! /i/smilies/16x16_robot-wink.gif

<table width="100%" border="0" cellspacing="0" cellpadding="10"><tr valign="middle" bgcolor="#3e463b"><td height="40" colspan="3" align="center">The ongoing IL-2 User's Guide project (http://people.ee.ethz.ch/~chapman/il2guide/)</a></td></tr><tr bgcolor="#515e2f"><td width="40%">FB engine management:
Manifold Pressure sucks (http://www.avweb.com/news/columns/182081-1.html)
Those Marvelous Props (http://www.avweb.com/news/columns/182082-1.html)
Mixture Magic (http://www.avweb.com/news/columns/182084-1.html)
Putting It All Together (http://www.avweb.com/news/columns/182085-1.html)
Those Fire-Breathing Turbos (Part 1 of 6) (http://www.avweb.com/news/columns/182102-1.html)</td><td align="center">

‚ =69.GIAP=Chap‚

69.GIAP (http://www.baseclass.modulweb.dk/giap/)</p></td><td width="40%" align="right" valign="top">Hardware:
Flight Simulation Performance Analyzed (http://www.simhq.com/_air/air_062a.html)
Building a home-made throttle quadrant step by step (http://forums.ubi.com/messages/message_view-topic.asp?name=us_il2sturmovik_gd&id=zkavv)
Sound Can Be Hazardous for Games (http://www6.tomshardware.com/game/20030405/index.html)</td></tr></table>

XyZspineZyX
08-29-2003, 05:01 PM
Huckebein_FW wrote:

- The same, though engines worn out faster.
- But you have to remember that soviet units also
- received american fuel for american planes.


But not always 100/130 fuel. 87 grade was supplied as well. And you have no clue what the Russinas tested it on, but we do know what the Americans tested it on.

Regards,

SkyChimp

http://members.cox.net/rowlandparks/corsairs.jpg