Merlin negative G cutout too quick?

[Crumpp]

now perhaps we can all stop guessing.

Exactly. There is no need to guess. Pilots who fly float carburetor equipped aircraft have been telling your community from the beginning the effect is instantaneous.

The physics and science of a float carburetor fuel metering system supports their experience.

There is a reason why allied pilots complained about it and why German pilots equipped with direct injection fuel metered engines could bunt to escape. It speaks volumes for the realism of your game that players complain as well.

The effect is instantaneous upon the application of negative accelerations. The instrumentation used in the report backs that up very nicely within the accuracy of a mechanical dial gauge accelerometer.

The problem is when people try to interpret things they don't understand and push it as fact.

You can see that in many of the "home-made" graphs pushed around the flight sim community where the author of the graph did not understand such things as TAS, EAS, CAS, or IAS or density altitude effects.

[klem]

Originally Posted by Crumpp

Exactly. There is no need to guess. Pilots who fly float carburetor equipped aircraft have been telling your community from the beginning the effect is instantaneous.

The physics and science of a float carburetor fuel metering system supports their experience.

There is a reason why allied pilots complained about it and why German pilots equipped with direct injection fuel metered engines could bunt to escape. It speaks volumes for the realism of your game that players complain as well.

The effect is instantaneous upon the application of negative accelerations. The instrumentation used in the report backs that up very nicely within the accuracy of a mechanical dial gauge accelerometer.

The problem is when people try to interpret things they don't understand and push it as fact.

You can see that in many of the "home-made" graphs pushed around the flight sim community where the author of the graph did not understand such things as TAS, EAS, CAS, or IAS or density altitude effects.

Yep, its probably almost instantaneous when it hits 0.1G. A pilot that currently fies a float-carburreted MkI Hurricane has told us that he estimates a cutout at 0.3G after a second or two (some people might call that 'instantaneous'), possibly instantaneous at negative G.

It would be a brave or arrogant person that was prepared to argue with the Royal Aircraft Establishmnent (RAE) who had the aircraft/engines to make tests with ( we don't ) and the skills and instrumentation to determine the problem. Beatrice Shilling was working for the RAE when she came up with her 'orifice'.

I just wonder how much factual documentary evidence will be needed before people stop thinking the early Merlins farted every time the pilot hiccupped.

[Crumpp]

Yep, its probably almost instantaneous

No probably to it, it is instantaneous. A Merlin engine sucks ~40-130 gallons per hour....there is not enough gas in the float bowl to fire the cylinders through one complete cycle.

Read the document again. Cut out occurs when it hits .9G on a mechanical dial gauge accelerometer. An acelerometer reads 1G at wings level or on the ground.

It only takes .1G of negative acceleration as measured on a mechanical dial gauge accelerometer to induce cut out.


That is 1/10th of a G...

By all means read that small amount of accelerations accurately on a dial gauge please.....

http://www.aircraftspruce.com/menus/...rs_falcon.html

The correct answer is "when the needle moves, cut out occurs...." That is what you see in the air with a float carburetor.

Crump, read again. It says at 0.9g negative acceleration and 0.1g instrument reading. Which means it will cut out fully when the measured acceleration reaches 0.1g (which may be different from the actual acceleration level experienced by plane and pilot).

The question is will the cut out appear in an on-off manner as we have now or will it be more a stepwise cut out as we had initially. My belief is that it will be rather a stepwise. With less g than level flight but with acceleration superiour to 0.1g the hydrostatic pressure in the lines and in the tank bottom will be less and my guess is that the engine will cough a little because of this.