Engines and accessories ground test

The "Queen of the Skies"
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Patrick Mussotte
Airman
Posts: 11
Joined: 07 Jun 2021

Engines and accessories ground test

Post Patrick Mussotte »

Hello fellow L049 pilots!
I've a problem with the ground test . Page 125 of the manual item 4 it is said to switch the blowers to high(with RPM <1200), then to increase RPM to 1800. I notice that when switching the blowers to high, RPM already increased around 1500. Fine so I increase a little bit more RPM to reach 1800 and apply item 6 which consist to switch blowers to low. Here again RPM drop to ~1500 because I didn't move the throttles. Here is my problem with items 7 ! When Idecrease RPM using the FE gang switches or the pilot switch, I notice NO decrease in RPM and NO lights coming on. Of course item 8 is not possible and the end of the runup is ok!
Am I doing something wrong or misunderstand something here? Thanks for your knowledge!
Cheers
Pat
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TreeTops
Technical Sergeant
Posts: 943
Joined: 07 Apr 2010

Re: Engines and accessories ground test

Post TreeTops »

Use the master propeller governor switch, (bind a key to increase/decrease in the A2A L049 input configurator).

The difference between the master propeller governor switch on the center pedestal and the engineer's governor switches is the speed of adjustment. The master switch changes rather quickly where the engineer's switches change slowly. Both do the same job, however it seems that the master propeller is used for all operations except fine adjustment to sync between propellers which is done by the engineer.
As an exercise, set the engines to about 1300 RPM, increase/decrease the master switch will cause quicker changes, where the engineers switches will cause a slow change and these can be done either individually or by using the gang plate.

To the ground testing. (Note different MP settings will result in different upper RPM number)
So after step 5 using the throttles to increase to 1800 RPM, Step 6 switching to low blower you will be looking at the MP gauges to note a decrease. This will result in the prop settling to around 1500 RPM approximately.
With the RPM still about 1500, step 7 use the decrease button for the master propeller governor and keep holding it for about 20 seconds. You will notice the props eventually drop to 1100 RPM and the yellow limit lights come on.
Step 8, increase the master propeller governor and keep holding it for about 20 seconds. You will notice the props immediately rise to about 1500 RPM and later the limit lights come on.

I have stress damage to engine 2 and the minimum RPM I got was 1140 for that engine. Accusim at work!!!
The same test can be done using the engineers switches only that they take much longer. I did get the limit lights for the minimum setting, but I couldn't get them for the maximum setting. Perhaps something in the coding.

You may have a question about what MP setting should be used for the test, and in my opinion it doesn't really matter, only that props should be about 1300-1500 RPM. This will allow the governor to drive the RPM down to 1100 and not have to increase RPM too much to reach the maximum limit.

If you read on, the Take off action 12 is to increase props using the master switch until the limit lights go on. This would sync all props at fully fine for take off.
After take off and the PM and RPM's are reduced to climb power, if necessary you could use the engineer's governor switches to sync the props to engine 1.
Cheers
Trev

Patrick Mussotte
Airman
Posts: 11
Joined: 07 Jun 2021

Re: Engines and accessories ground test

Post Patrick Mussotte »

Hello TreeTops!
Thank you very much for your answer. I guess the point is I don't wait enough for the RPM decrease. These old ladies need more "patience" and care :D
Best regards
Pat
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TreeTops
Technical Sergeant
Posts: 943
Joined: 07 Apr 2010

Re: Engines and accessories ground test

Post TreeTops »

Enjoy the Connie. Its a beauty to fly for sure. Don't be afraid to ask questions, as there are plenty of people here who have many 100's/1000's hours on this plane.
Cheers
Trev

Patrick Mussotte
Airman
Posts: 11
Joined: 07 Jun 2021

Re: Engines and accessories ground test

Post Patrick Mussotte »

I just made a short trip from KMSY to KCRP and everything worked like a charm 8) .
Cheers
Pat
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