proppellers amplitude

[amarante68]

Hi

I built all gauges of the Baron 58 and programmed most of these.

But 1 gauge gives me problems.

The PROP AMPS (proppellers amplitude)gauge founded on the Baron.

Is there an ofset that would be usfull to calculate the amplitude of proppell ers?

I know we can find the ofset for vibration on jets. But it does nothing for the prop aircraft.

Maybe i need more explainations about PROP AMP.

:?:

[Pete Dowson]

The PROP AMPS (proppellers amplitude)gauge founded on the Baron.

Prop Amplitude? What is that please? And where is this gauge -- I don't see it anywhere on the default FS2004 Baron?

Is there an ofset that would be usfull to calculate the amplitude of proppell ers?

I don't know. The only thing I can think of for a propeller which might be called "amplitude" is the pitch. That is controlled by the propeller pitch value (offsets 088E and 0926 for the two engines). There are also values for the propeller "Beta" blade angle, which is either the same, or presumably related, to the pitch. See offsets 2418 and 2518.

I know we can find the ofset for vibration on jets. But it does nothing for the prop aircraft.

Ah, is your "prop amp" related to vibration? I see nothing anywhere in the variables inside FS which may relate to that for props I'm afraid. Are you sure FS models what you want?

Regards,

Pete

[amarante68]

When I was young I played a game.

Once the bath half full, I start to make a wave. This wave is bouncing side by side. Then I folow the frequence of the wave with my hand.

Then amplitude of the wave is growing up very fast until it is on the floor.

We saw this happening with brand new bridge the felt because of the wind.

This can happen with proppellers.

On the real aircraft we can find the gauge PROP AMP.

Not in Fs.

Maybe I will use RPM and airspeed to program the gauge to show a normal value. Just to make the gauge not totaly dummy.

But I dont know yet.

This value should go up wile the proppeller get older.

Well all this is what I understood after few research I made on the net.

I didnt find any easy explainations about it.

The ofset vibrations is for turbine engine only. King air works because it is a turbo prop. But on piston aircraft the value stays 0.

[Pete Dowson]

Then amplitude of the wave is growing up very fast until it is on the floor.

You have to get just the right input frequency. That's called resonance, and the same principle is used to tune frequencies in radios. The bath is replaced by a capacitance and an inductance which act in a kind of push-me-pull-you fashion which grows in amplitude for the specific tuned frequency, and acts opposing others.

This can happen with proppellers.

So, are you talking about the amount of bending the propellers are doing at their tips, or something? i.e. akin to the engine vibration measures in jets (the latter are of course checked in case they go out of balance -- bird srtrikes or other damage can take out enough vanes for this, I understand).

On the real aircraft we can find the gauge PROP AMP.

Not in Fs.

Ah, if FS doesn't simulate this and give you a value, then obviously that's why it doesn't appear and why I cannot map an offset for it.

There are many many parts of an aircraft not simulated in FS, even many subsystems either not simulated at all or only given token support. If you are really interested in completing these things then you may want to take a look at the Project Magenta pmSystems project. Although aimed at present at jet airliner systems, the idea and implementation are general enough, I believe, for much wider application.

Regards,

Pete

[airforce2]

The short answer: FS does not perform any meaningful simulation of engine vibration for any type of engine. Values produced (for jets only) are notional.

The prop amp indication is an equivalent to the engine vibration readings in a jet engine. The prop amplitude is a measurement of the peak amount of vibratory motion per unit time, and is proportional to the magnitude of the mass imbalance on the prop assembly. Resonant vibratory stress becomes a problem if either an excessive mass imbalance is present (prop/gearbox/engine is not balanced properly) or also possibly by the resonant effect of the regular power pulses applied to the prop by the power-stroke detonation in each cylinder of a reciprocating engine. This explains why some recip powered aircraft have ops limits which prohibit sustained operation of the engine in certain RPM ranges that produce this power pulse resonance.

That said, modeling of vibration response of a particular recip/prop combo is well, well outside the bounds of what MSFS will do. It'd be an interesting add-on feature.

Cheers