Question about cruise power settings

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Moose
Posts: 6
Joined: 20 Sep 2006, 14:10
Location: Richmond, Virginia, USA

Question about cruise power settings

Post by Moose » 28 Sep 2006, 19:03

First of all...this is an amazing airplane. I really do think SibWings has earned the title of "greatest virtual cockpit ever created" in FS2004. The entire package is fantastic, really...sound, flight model, cockpit, all of it. Easily the best US$26 I've spent in quite a while. :)

I've got some questions about cruise performance. Typically I have been setting the prop around 2300-2350 RPM, leaning the engine to peak EGT, and then moving the power back until the fuel flow is around the 65-75% marks on the gauge (around 10 gallons per hour, I think). But when I do this, I find that I'm only getting around 105-110 knots indicated airspeed, at any altitude from sea level up to about 6500 feet. Is this normal? From the markings on the indicator, and from other things, I had assumed that I would be able to get at least 120 knots indicated out of it at reasonable cruise settings, but the only way I can do that is to go full throttle and full rich at very low altitude. Should I be leaning the mixture to peak EGT, or a certain amount rich or lean of peak EGT?
Lewis "Moose" Gregory

S91C
Posts: 83
Joined: 31 Mar 2006, 13:31
Location: Sweden

Post by S91C » 28 Sep 2006, 19:49

Hi there...

I´ve not reflected at this in the "cyberone".
In the real thing there should be no problem to get around 121 Kt (225 km/h) at the 75 mark, 2350 rpm and no leaning at about 2000-3000 ft. At least not in our bird SE-KVZ. I guess it could be a difference between the models.

Normaly we not lean at all under 5000ft as the wear to the engine is to big. (important when you have to take care of the remaining hours on the engine....)

//Per
Last edited by S91C on 29 Sep 2006, 12:44, edited 2 times in total.

Redhawk
Posts: 1
Joined: 17 Sep 2006, 12:54
Location: Nakhon Ratchasima / Thailand
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Post by Redhawk » 29 Sep 2006, 05:31

Hello there....

The right proceedure for power settings and leaning should look like this.

Increase power: Raise the RPM, then raise the throttle setting, bear in mind there is always a max. manifold pressure (MP) setting for a given RPM setting.

Decrease power: Lower the throttles setting to the necessary MP then lower the RPM, RPM value should not be below permitted RPM minimum value for this MP.

After this the engine could be leaned, before establishing, for example a climb power setting, the mixture needs to be set full rich then change power for climb as above and lean again.

Regards

Oliver

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SuredT
Posts: 36
Joined: 24 Sep 2006, 17:40
Location: Netherlands

Post by SuredT » 29 Sep 2006, 12:29

Hello,

The PH-RLA (91D with 180 HP) with a powersetting of 24" and 2400 rpm is cruising at a mere 110 kts.
So the figures in the sim are very realistic.

Regards,
Sjoerd

Moose
Posts: 6
Joined: 20 Sep 2006, 14:10
Location: Richmond, Virginia, USA

Post by Moose » 30 Sep 2006, 22:19

Thank you all. I mostly fly HB-DBL because of the English-unit instrumentation, I tried out the 91B last night and noticed that despite 20 fewer horsepower it seemed quite a bit faster, or at least it accelerated faster. I assume the 91B weighs a good bit less than the 91D so that might account for it.

Sounds like 110 knots indicated is a good cruise for DBL, and that's fine with me. It just means I get to enjoy the Safir a little longer wherever I'm going. :)

Thanks again!
Lewis "Moose" Gregory

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