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SeaVee
04-17-2007, 06:06 AM
I thought I would share with you all an interesting excerpt and bit of trivia from the book The Most Dangerous Enemy by Stephen bungay about the Battle of Britain.

This is in regards to the RAF planes during the BoB using carburetors and not being able to hold negative G without the engines sputtering. This first part is not likely any news to most of you but the footnote that follows was new to me.

"...the most significant technical advantage the 109 enjoyed over both British fighters was not due to the airframe but the engine. The DB601 (in the Messerschmitt) was fuel injected, whilst the Merlin had a float carburettor. When the Merlin was subject to negative G (creating excessive upward force rather than downward force), which would occur in moving into a dive (a manoevre called 'bunting'), the fuel supply to the engine stopped and the engine would cut."

And here is the interesting footnote:

"... the first solution to the float carburettor problem was devised by one Miss Shilling of the RAE, who invented a restricter orifice which stopped all the fuel from being flung upwards in a negative-G dive. This inevitably became known to the pilots as 'Miss Shilling's Orifice'. Later, the Bendix Stromberg carburettor was put into production and elimiated the problem completely."

SeaVee
04-17-2007, 06:06 AM
I thought I would share with you all an interesting excerpt and bit of trivia from the book The Most Dangerous Enemy by Stephen bungay about the Battle of Britain.

This is in regards to the RAF planes during the BoB using carburetors and not being able to hold negative G without the engines sputtering. This first part is not likely any news to most of you but the footnote that follows was new to me.

"...the most significant technical advantage the 109 enjoyed over both British fighters was not due to the airframe but the engine. The DB601 (in the Messerschmitt) was fuel injected, whilst the Merlin had a float carburettor. When the Merlin was subject to negative G (creating excessive upward force rather than downward force), which would occur in moving into a dive (a manoevre called 'bunting'), the fuel supply to the engine stopped and the engine would cut."

And here is the interesting footnote:

"... the first solution to the float carburettor problem was devised by one Miss Shilling of the RAE, who invented a restricter orifice which stopped all the fuel from being flung upwards in a negative-G dive. This inevitably became known to the pilots as 'Miss Shilling's Orifice'. Later, the Bendix Stromberg carburettor was put into production and elimiated the problem completely."

stalkervision
04-17-2007, 06:33 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SeaVee:
I thought I would share with you all an interesting excerpt and bit of trivia from the book The Most Dangerous Enemy by Stephen bungay about the Battle of Britain.

This is in regards to the RAF planes during the BoB using carburetors and not being able to hold negative G without the engines sputtering. This first part is not likely any news to most of you but the footnote that follows was new to me.

"...the most significant technical advantage the 109 enjoyed over both British fighters was not due to the airframe but the engine. The DB601 (in the Messerschmitt) was fuel injected, whilst the Merlin had a float carburettor. When the Merlin was subject to negative G (creating excessive upward force rather than downward force), which would occur in moving into a dive (a manoevre called 'bunting'), the fuel supply to the engine stopped and the engine would cut."

And here is the interesting footnote:

"... the first solution to the float carburettor problem was devised by one Miss Shilling of the RAE, who invented a restricter orifice which stopped all the fuel from being flung upwards in a negative-G dive. This inevitably became known to the pilots as 'Miss Shilling's Orifice'. Later, the Bendix Stromberg carburettor was put into production and elimiated the problem completely." </div></BLOCKQUOTE>


I find the "merlin carburetor cut-out effect" highly annoying and overdramatized in BOB2. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

luftluuver
04-17-2007, 06:34 AM
There was more to the cutout than that.

The neg G cutout was a 2 stage event. At the onset of of negative g fuel was forced to the top of the float chamber which exposed the main jets to air. This caused the first momentary lean cutout. If a negative g condition continued, the floats racted to the reverse of normal conditions and floated the wrong way, that is, they floated to the bottom of the float chamber. The needle valve opened wide, allowing full fuel pressure from the engine driven pump to flood the carb. An exceptional rich mixture was then admitted into the supercharger causing the more serious rich cutout.

G White. Allied A/C Piston Engines of WW2 pg66

There was 2 orfices, one for 12lb boost and another for 16lb boost.

LStarosta
04-17-2007, 06:36 AM
Dammit I was hoping for something else here...

stalkervision
04-17-2007, 06:38 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by LStarosta:
Dammit I was hoping for something else here... </div></BLOCKQUOTE>

better ask 'Miss Shilling' for that.. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

msalama
04-17-2007, 06:44 AM
Poor girl http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif I'm sure there's been no end to the jokes after this (as such a) brilliant invention of hers http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

PFflyer
04-17-2007, 08:56 AM
If you watch, right at the begining of the old movie Battle of Britian, a Hurricane does a roll on a fly-by, the engine cuts from being lean, and then black smoke comes out from being over rich before it catches it's breath and runs right again.

Check it out.....

Xiolablu3
04-17-2007, 09:12 AM
I didnt actually have too much trouble with Neg G cutout in BOB2 when I tried it, it seemed much more mild than say the Hurricane Mk1 in IL2 where the engine stops completely if you hold neg G for much more than a second. It starts to cut out the instant you pull some neg G's.

I am starting to wonder if I was playing BOB2 on easy settings. I didnt change anything, just started the game and played. Anyone know what settings htose are?

leitmotiv
04-17-2007, 09:22 AM
BOB2 the engine does not die completely like it does in IL-2. In the accounts I've read, I've never seen anything about complete shut down---see PFflyer's post above for the visual and Luftluuver for the technical.

msalama
04-17-2007, 11:39 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Anyone know what settings those are? </div></BLOCKQUOTE>

Quite easy IIRC.

I'm pretty sure I did my tinkering with realistic settings though, but never ever checked out the Novice_Stronger_Bullets & Novice_Target_Size parameters (thanks SeaVee). Also I've had my configs go all mutinied on my sordid a*se once or twice before and I didn't manually check the file this time either, so... http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Gotta test a bit more w/ v2.06 I think. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

StellarRat
04-17-2007, 05:40 PM
This is not a huge problem if you remember to roll the plane on it's back before you dive. You only get the cut-out when you pull the negative G's to enter the dive, not just because you're diving.

LStarosta
04-17-2007, 05:47 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by StellarRat:
This is not a huge problem if you remember to roll the plane on it's back before you dive. You only get the cut-out when you pull the negative G's to enter the dive, not just because you're diving. </div></BLOCKQUOTE>

Thank you, Professor Obvious.

StellarRat
04-17-2007, 05:55 PM
That was for the benefit of the new pilots. Professor Obxious. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

leitmotiv
04-17-2007, 06:10 PM
Yes, I would like to have a dollar for every time I forget to do this in the excitement of the chase and my Hurricane I/Gladiator/I-153/I-16/CR.42/G.50 conks out dead leaving me fiddling with my ignition with knickers around my ankles!

heywooood
04-17-2007, 06:14 PM
fiddlin with yer what? http://forums.ubi.com/images/smilies/10.gif http://forums.ubi.com/images/smilies/mockface.gif

AVG_WarHawk
04-17-2007, 09:41 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by luftluuver:
There was more to the cutout than that.

The neg G cutout was a 2 stage event. At the onset of of negative g fuel was forced to the top of the float chamber which exposed the main jets to air. This caused the first momentary lean cutout. If a negative g condition continued, the floats racted to the reverse of normal conditions and floated the wrong way, that is, they floated to the bottom of the float chamber. The needle valve opened wide, allowing full fuel pressure from the engine driven pump to flood the carb. An exceptional rich mixture was then admitted into the supercharger causing the more serious rich cutout.

G White. Allied A/C Piston Engines of WW2 pg66
</div></BLOCKQUOTE>

Precisely! "The Double Whammy"

Esel1964
04-17-2007, 10:09 PM
To prevent the upward liquid flow,and solve the problem,"Miss Shilling's Orifice" must have been quite small. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

stathem
04-18-2007, 03:42 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Esel1964:
To prevent the upward liquid flow,and solve the problem,"Miss Shilling's Orifice" must have been quite small. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

I prefer the expression "tight"