Fulqrum Publishing Home   |   Register   |   Today Posts   |   Members   |   UserCP   |   Calendar   |   Search   |   FAQ

Go Back   Official Fulqrum Publishing forum > Fulqrum Publishing > IL-2 Sturmovik: Cliffs of Dover > Technical threads > FM/DM threads

FM/DM threads Everything about FM/DM in CoD

Reply
 
Thread Tools Display Modes
  #201  
Old 08-12-2011, 01:38 AM
whoarmongar whoarmongar is offline
Approved Member
 
Join Date: Apr 2011
Posts: 265
Default

Engine flooding was a very common and well known event.
Indeed an aircraft with a flooded engine was very often reported as being hit and going down trailing black smoke when in fact all that had happened was the pilot had flooded the engine usually by slaming the throttle open and or taking evasive diving manouvers.
Reply With Quote
  #202  
Old 08-12-2011, 01:57 AM
catito14 catito14 is offline
Approved Member
 
Join Date: Jul 2011
Location: Buenos Aires, Argentina
Posts: 119
Default

Quote:
Originally Posted by Ze-Jamz View Post
you serious?
Obviously i didn´t made the comparison in the right way
Reply With Quote
  #203  
Old 08-12-2011, 03:02 AM
Al Schlageter Al Schlageter is offline
Approved Member
 
Join Date: Oct 2007
Posts: 657
Default

Quote:
Originally Posted by Crumpp View Post
The fuel metering system does not change and the air/fuel ratio does not change very much.

That is the whole purpose of leaning the mixture to maintain that ratio as the density altitude gets higher.
What ever you say Eugene. You can contact Graham White and tell him he is a clueless gamer.

The fuel metering certainly does change when the fuel pump is pushing more fuel through the jets.
Reply With Quote
  #204  
Old 08-18-2011, 02:08 AM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

Quote:
The fuel metering certainly does change when the fuel pump is pushing more fuel through the jets.
I did not catch your explaination of the your "stages" Milo, it is clearer what you are saying. I thought you were saying it was more serious in the second stage of the supercharger.

If you are in the second stage of your supercharger then your altitude is increased and the air density is decreased. To maintain the same ratio of fuel and air you must reduce the amount of fuel.

It is not a two "stage" event, it is two different types of cut outs you can experience with a float type carburetor. You can experience both of them in one flight pulling negative G's in your float type carbureted engine.

You either have a lean cut out or a rich cut out. A lean cut out occurs when you subject the airplane to rapid onset negative G such as a bunt. The float rises up and shuts off the flow of fuel.

A rich cut out occurs when you subject the airplane to low amounts of prolonged gradual onset Negative G. The float does not rise up and shut off the flow of fuel. Instead fuel continues to flow, the engine sputters and skips but does not cut out. The fuel collects in the top of the bowl forcing the float down, opening the fuel flow to maximum and flooding the engine. This is more serious because the engine will not automatically restart like a lean cut out will. The engine is flooded and the fuel amount must be reduced in the cylinders.

If you take a float carburetor and subject it to negative G's, the engine cuts out immediately in a lean cut out.

Even in a small 180hp Lycoming engine.....sipping 10 gallons per hour empties the bowl immediately.

Quote:
Accident - The pilot of a southern California Long-EZ was seriously injured and his passenger suffered a broken hip when the airplane crashed into a dry riverbed. The eyewitnesses to the accident reported that the airplane was doing aerobatics. It appeared to enter the beginning of a loop, did not have enough speed, fell out of the maneuver. The engine stopped. (negative "g" will cause a carbureted engine to suffer fuel starvation) the aircraft nosed over and spiraled down to about 100 feet, where its wings were leveled and it descended until it struck the ground. The aircraft hit a 20 degree embankment almost wings level and slid forward only about two feet. There was no fire, although the right fuel tank was ruptured.
http://v2.ez.org/cp34-p5%28.htm

You take a large 12 cylinder Merlin gulping 120 gallons per hour and the small amount of fuel in the carburetor bowl will not last a blink of eye.....

The engine will quit....
The prop will windmill....

AND as soon as the float opens back up and fuel flow is restored the engine will restart.

Anything else is gamer fantasy.

Even with a TBI or pressure carburetor, if you pull asymmetrical loads, the engine will skip as the fuel metering changes....

Quote:
The TBI must be mounted in an orientation that places the metering tube in a horizontal plane. If the metering tube is not in a horizontal plane, positive or negative "G" forces acting on the diaphragm will alter fuel metering.
http://www.ellison-fluid-systems.com...l/section2.htm
Reply With Quote
  #205  
Old 08-18-2011, 02:50 AM
CaptainDoggles's Avatar
CaptainDoggles CaptainDoggles is offline
Approved Member
 
Join Date: Jun 2011
Posts: 1,198
Default

Quote:
Originally Posted by Crumpp View Post
Anything else is gamer fantasy.
Please understand most of us know that the ingame behaviour is incorrect and that the flight models are not 1:1 with reality in many aspects. It's not "gamer fantasy" so much as it's "the simulation model is incomplete".
Reply With Quote
  #206  
Old 08-18-2011, 12:38 PM
Al Schlageter Al Schlageter is offline
Approved Member
 
Join Date: Oct 2007
Posts: 657
Default

Your reading comprehension certainly leaves a lot to be desired Eugene. So nice of you to repeat what I already said.
Reply With Quote
  #207  
Old 08-18-2011, 02:39 PM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

Quote:
Your reading comprehension certainly leaves a lot to be desired Eugene. So nice of you to repeat what I already said
No it was not a repeat. It was to clearly put out what happens in a float bowl type carburetor when subjected to negative G.

You wrongly stated it was a "two stage" event with the implication being it takes time.

No, it happens almost immediately and is two separate events brought about by subjecting the fuel metering system to negative G.

In a lean cut out, it immediately quits but will restart as soon as fuel is delivered.

A rich cut out immediately begins skipping and then quits.... It does not restart immediately and delivery of more fuel only prolongs the restart.

Even a pressure carb or TBI will have issues under Negative G. It is a distinct disadvantage for piston power fighters using such a metering system.

Only a direct injection metering system is immune to accelerations.

Last edited by Crumpp; 08-18-2011 at 02:44 PM.
Reply With Quote
  #208  
Old 08-18-2011, 02:52 PM
Crumpp's Avatar
Crumpp Crumpp is offline
Approved Member
 
Join Date: Feb 2008
Posts: 1,552
Default

Quote:
Please understand most of us know that the ingame behaviour is incorrect and that the flight models are not 1:1 with reality in many aspects. It's not "gamer fantasy" so much as it's "the simulation model is incomplete".
I understand and don't take offense please at the "gamer fantasy." I refer to people who distort the way the physical works to get some desired advantage in a game.

There was a distinct disadvantage in fuel metering technology. One that was frustrating for Allied pilots in a dogfight. Solving it got the attention of aeronautical research agencies on both sides of the Atlantic.

Pressure Carbs and TBI helped considerably but were not in use during the Battle of Britain.
Reply With Quote
  #209  
Old 08-18-2011, 03:13 PM
Al Schlageter Al Schlageter is offline
Approved Member
 
Join Date: Oct 2007
Posts: 657
Default

Quote:
Originally Posted by Crumpp View Post
No it was not a repeat. It was to clearly put out what happens in a float bowl type carburetor when subjected to negative G.

You wrongly stated it was a "two stage" event with the implication being it takes time.

No, it happens almost immediately and is two separate events brought about by subjecting the fuel metering system to negative G.

In a lean cut out, it immediately quits but will restart as soon as fuel is delivered.

A rich cut out immediately begins skipping and then quits.... It does not restart immediately and delivery of more fuel only prolongs the restart.
LOL!!!

It is a 2 stage event. First there is the lean cut out which is followed by the rich cut out. They don't, and can't, occur simultaneously. Yes it takes time!!! Your 'almost immediately' says so.
Reply With Quote
  #210  
Old 08-18-2011, 04:42 PM
CaptainDoggles's Avatar
CaptainDoggles CaptainDoggles is offline
Approved Member
 
Join Date: Jun 2011
Posts: 1,198
Default

It is not a two-stage process. What you are describing are two separate phenomena, occurring sequentially.

A lean mixture cutout is not necessarily followed by a rich mixture cutout.

Similarly a rich mixture cutout can happen without being preceded by a lean mixture cutout.
Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 10:39 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright © 2007 Fulqrum Publishing. All rights reserved.