Merlin negative G cutout too quick?

[IvanK]

Yep every G meter I have used for the last 30 years uses 1G as a datum.

I have the entire document (lots of maths), there are is no list in the document as to the equipment being used. The term "G" is standard aviation terminology though. The snippet below comes from a comment in the covering letter to the document discussing testing methods used versus the nature of the original problem of G cut out in unmodified aeroplanes. Again the G used is unambiguous to me. The phenomenon occurring at "0.1 to 0g"



I will look through the second RAE doc that deals with the devices being tested to overcome the cutout (not very well either according to that document) to see if their are any equipment details in there.

Edit. The second document equipment list makes no mention of the Type of G meter used either. It simply lists the specific fuel system in each of the aircraft tested.

[IvanK]

Yes but common car accelerometers are primarily used to determine lateral and longitudinal accelerations.
The Bob weight or whatever device is used sits at rest with 1G vertical but )g lateral and Longitudinal. Typically
these are used to determine braking effectiveness



Motor transport investigators use both including vertical accelerations referenced to 1G.

[VO101_Tom]

Originally Posted by cheesehawk

I've only used car accelerometers (which is why I questioned your docs originally) and they always use 0.0g as the base point. Wondered if that came from the English system or German, as they were the original hard-core car racers (ok, someone flame me here, cuz I'm just guessing!) People using different systems would have different scales for the same thing, take the intake manifold pressure gauges in British, German, and American aircraft for example.

http://forum.1cpublishing.eu/showpos...8&postcount=33

[VO101_Tom]

Originally Posted by cheesehawk

Again, I'm not here to teach physics... Done with explaining basic concepts to the uninformed.

?
It is better if you do not want to teach me anything, especially if you do not understand what is the difference between the aircraft and automobiles accelerometer (vertical (1G) and horizontal (0G) installation). Should not be pompously, especially when talking about stupid things ...

[TomcatViP]

Originally Posted by IvanK

Yep every G meter I have used for the last 30 years uses 1G as a datum.

I have the entire document (lots of maths), there are is no list in the document as to the equipment being used. The term "G" is standard aviation terminology though. The snippet below comes from a comment in the covering letter to the document discussing testing methods used versus the nature of the original problem of G cut out in unmodified aeroplanes. Again the G used is unambiguous to me. The phenomenon occurring at "0.1 to 0g"



I will look through the second RAE doc that deals with the devices being tested to overcome the cutout (not very well either according to that document) to see if their are any equipment details in there.

Edit. The second document equipment list makes no mention of the Type of G meter used either. It simply lists the specific fuel system in each of the aircraft tested.

In your document it is said "were reported" and "feb 41"

If the date is of paramount importance for the time frame the fact that they are discussing "reported" fact and not "instrumented" let me think that the G-cut out were measured by a direct reading of a G meter or reading of a graph after the flight. The graphometer would hve been most presumably fixed inside the rear fuselage or otherwise just behind the pilot in place of the radio what makes it doubtful. As the rear fuselage option it less precise than a direct reading by the pilot (aft position) we can speculate that this were read or filmed (a Technic used by the Germans as I know).

Anyway the law of distribution of acceleration states that the Accel a point A (aA) equate Accel at a point b + ABxf(dAlpha/dt²) + AB f(d(Aplha²)dt)

where AB is the distance btw point A and B and alpha is the angle of rotation of the line AB in the plane of travel. D/dt is the time derivation and d/dt² is twice the time of derivation (d/dt(d/dt))

So let's say that
A is the carb float
B is the pilot

when the plane is traveling at cruise speed (300kph+) the radius of turn due to a 1 G push over is huge. Hence Alpha is really small. We can then neglate the third term in Alpha²

Regarding the second term, it translate the influence of the inertia gained wth the rotating mvmt around the CG during the push over. As the mass of the Carb float itself is supposedly far less than that of the entire plane well we can say that if yes this term play it's part when studying the float, it won't have any influence in the value of the G read.