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ustyva

Super charger control

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The four supercharger switches are interconnected,

 

The procedure to switch from low to high blower in the climb is to reduce manifold of one engine. engage the resp. super charger. to high blower. adjust the MAP and repeat for the other engines.

 

could you make them independent?

 

Thanks.

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I was wondering about this, too. I wondered if XPlane switched them all at once...

 

Rob Smith.

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Rico-

 

Interesting question.  We modeled them to be done all at one time, as that is the technique used by NCA, the operator who's airplane we used for this product.  (Their chief flight engineer has been incredibly helpful on the technical and operating aspects of this product.) 

 

In the POH itself, we also have this on page 208:

 

"When critical altitudes for low blower have been reached, close
throttles to approximately ½ open to avoid excessive manifold pressure,
and switch superchargers to “HIGH.” Reset throttles to obtain
desired manifold pressure."

 

With this guidance we modeled them to be thrown all at one time.

 

However- yes- we can give you the ability to do them individually if you like.  We added it to the task list.  Look for it in an update build.

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However- yes- we can give you the ability to do them individually if you like.

 

That would be excellent!

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Since there's kind of a supercharger discussion on here, I gonna ask a question I have here instead of starting a new thread.

 

I noticed something odd going on in the last flight I took. I had the superchargers turned to "high" during cruise, after beginning the descend and doing the descend checks via the AFE I flew into some light rain. Since the AFE controls the engine settings automatically, it apparently turned on the carburetor heating (I assume because of the detected rain?), I didn't notice it at first because I was busy reading some airport charts, but suddenly I had a carburetor engine damage warning and all the engines were in the orange already, whereas the carburetor temps were just slightly above 15°c at this time.

 

As far as I'm concerned, and what's stated in the manual, the carburetor max temps with superchargers on "high" is 15°c, now I'm not sure if it's a bug or not but I suspect that I was supposed to turn the superchargers back to "low" for the descend, I assumed that the AFE would do that when running the descend checks but it didn't, and when I flew into rain it automatically raised the temps to avoid icing.

 

The question I have now: Is this how it should be or is it a bug? I mean if I wouldn't have forgotten to turn the superchargers back to low no damage would have occured. Unfortunately I had no time to test if the AFE raises the temps above the 15°c during cruise when the superchargers are on high and it's raining and I had no time yet to reproduce what happened during the descend.

 

Thanks.

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I assumed that the AFE would do that when running the descend checks but it didn't, and when I flew into rain it automatically raised the temps to avoid icing.

 

I don't think the AFE ever changes supercharging..., don't assume.  The AFE does manipulate carb heat "intelligently" but maybe you found a case where the logic failing to include supercharging created a gotcha.  Best to stay on top of what AFE does and doesn't do... just imagine he is a new hire and you don't trust him yet just like any copilot.

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So, first time fiddled with the supercharger. I've not had any big reason to use the superchargers before, as often you fly at low altitude or air pressure. But I wanted to test it out in my last flight while climbing. According to the charts I should use the high setting of the supercharger at about FL090 in climbing phase. So before stepping from low blower to high blower, I reduced the throttle and then turned on the high supercharger, after that I adjusted values of throttle to match charts, prop-speed stayed the same and should according to charts.

 

What I did notice in this case was the opposite of what I expected. The speed decreased, while I thought it would increase.

 

Have I misunderstood the utility of high supercharger, am I doing something wrong?

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