Constant rpm props

[cavity]

I have been flying the Convair 580 for a bit now and was wondering if there is a line that you can put in the airfile to create constant rpm props no matter the power setting?  After reading up on the Convair, it said that prop rpm was 1020 and that the blade angle was automatically adusted for the power setting.  Anyway to recreate this in the airfile?  Thanks, Todd

[jknight8907]

A constant-speed prop is controlled with the prop lever (the blue one) between the throttle and mixture. Pull out/back and rpms decrease. Push in/up and rpms increase. After setting the desired rpm the governor maintains that rpm by adjusting the angle of the prop blades. So if you increase power, the angle gets larger to keep the speed the same. If you decrease power, the angle gets smaller. If you decrease more than a certain amount, the angle can't get any smaller and the prop rpm decreases. Same for increasing power.

[cavity]

What in the aircraft cfg controls that prop rpm?  When I set it at 1020 rpm then increase the power, the rpm rises too.  If I have the power up and try to decrease the rpm, it will only drop to  1400 rpm or so but that is it.  I tried adjusting the gear ratio and the min gov rpm, but that didnt change anything.  Anybody out there who builds prop planes who can offer an explanation?  Todd

[jknight8907]

Nothing in the .cfg file needs to be adjusted for this to work. It should already be like the real airplane is. You're probably just adding so much power that the prop govenor has the blades at max pitch but that's not enough. 1020 rpm sounds quite low for a piston engine.

At what power settings is all of this happening?

[gr31]

 The 580 is powered by Allison turboprops, and less than 1200 RPM would be rather low for any turbo with normal props. Where did you find that information? It might apply to a propeller conversion that uses the low speed "paddle" type propellers, and not to the normal installation that the model represents.

[jknight8907]

Ooooo.....turboprop...I was thinking of the old piston airliner.

Anyway.

What model is it? I'll download it and take a look.

[gr31]

[cavity]

I subscribe to Airways mag and they did an article on the Convair 580.  It says the Allison spins at 13,820 rpm and is coupled to a gear 13.5 gear reduction.  This produces a prop that turns at a constant rpm of 1020.  It goes on to say that they are constant speed engines, that the power levers control the pitch of the blades directly, then governors add fuel as necessary to maintain the rpm with that pitch position at all times.  I hope this helps.  I guess what I am asking is if there is a way to couple the pitch of the blades to the power setting in FS9?  todd

[gr31]

[jknight8907]

You might try assigning the prop axis to your joystick throttle, and leaving the acutal throttle at 100%. That may simulate the real-life workings.

EDIT: No, that won't work. You'll just have to fly it like a 'normal' turboprop. Sorry.

[gr31]