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pavane88

Engine performance difference

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Hello.

In LSGI after engine start, tit, fuel flow, torque, rpm are the same for all engines

However, when switching to hsgi, engine no.1 is higher than tit 100 degrees and ff is higher than 200 ppm(Torque and rpm are the same as other engines) And after 2 ~ 5 minutes, ff and tit decrease similar to other engines

Symptoms appear only at first start-up and do not appear during second or subsequent operation(The morning outside temperature is about 0 to 5 degrees)

I exchanged MFC and TD VALVE

I checked TD Amp Test

 

How are your opinions?

 

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Is the engine operating within limits? If so, disregard the differences as there is no limit for symmetrical operation in HSGI.

Otherwise, you might consider checking rigging with the valve housing, or swap it with a known good valve housing, as long as the Fuel Control has already been eliminated. I know the prop causing fuel flow problems sounds weird, but I've had it cause stranger problems in HSGI.

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I'm with lquest - out of rig prop can do some wierd stuff, but if within limits ignore and continue.  Can you give actual numbers, ie. OAT, air pressure, ff, torque, TIT,  RPM?

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The torque not being higher with FF and TIT makes me think you should recalibrate that torque meter first.

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On ‎2‎/‎22‎/‎2017 at 7:46 PM, pavane88 said:

Hello.

In LSGI after engine start, tit, fuel flow, torque, rpm are the same for all engines

However, when switching to hsgi, engine no.1 is higher than tit 100 degrees and ff is higher than 200 ppm(Torque and rpm are the same as other engines) And after 2 ~ 5 minutes, ff and tit decrease similar to other engines

Symptoms appear only at first start-up and do not appear during second or subsequent operation(The morning outside temperature is about 0 to 5 degrees)

I exchanged MFC and TD VALVE

I checked TD Amp Test

 

How are your opinions?

 

You state the RPM and Torque are the same as other engines until 2 -5 min...

When the FF and TIT decrease after 2-5 min does the RPM decrease? Torque decrease? There should be some other indication changes taking place; TIT and FF decrease to a fix pitch prop (Ground Idle) the RPM should decrease as well as Torque.   

In LSGI your FC is governed and therefore you do not see the difference once in HSGI the FC get input from Pressure and Temperature which may be causing your issue.

Try turning your inlet anti ice on for a min or two (or three) before you start (turn off prior to start) and see if it changes your indications. By warming up the air inlet housing you may be able to influence the FC temperature input.

 

Interesting issue but as the others have said as long as the engine is operating within limits in all other ranges and in flight disregard and continue operation.

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Hence fuel control units (FCU/TDV) are eliminated, is it possible the defect cause is related to one (or more) acceleration bleed air valve delay in closing (sticky)..?

 If so, certainly the TIT at the time will be higher than normal until valve/s are forced to close; as for other indication, I am not sure if the fuel will be higher or not (air to fuel ratio); the torque should show somehow less until defective valve/s are closed.

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