Pitch Adjustment of the Prop

 Abstract:  Thread discussing adjustment of propeller pitch, proper lubrication, speeds for changing settings, and expected RPM levels.

Subject: Pitch adjustement of the prop
From: "prg55100" <pierrot.greff
Date: 3/20/09 3:43 PM
To: G109_Pilots@yahoogroups.com

Dear all,
I feel that my cruise pitch is a bit too much engaged. When swapping from climb to cruise the engine needs time to come to 2500 rpm. Grob advised to often fine clean and lubricate the prop adjustment rods below the spinner which helped. I was wondering if somebody had the same concern and readjusted its prop as per the picture filed by jb92563 recently? jb92563 did you?  How sensitive is it?   It seems straight forward to re-adjust. Isn't it? Somebody to comment?

Pierrot

Subject: RE: [G109_Pilots] Pitch adjustement of the prop
From: Jackie
Date: 3/20/09 5:02 PM
To: Grob Group online

Hello Pierrot,
Jackie here. Hope you are doing well.
I had a similar problem and Mike Shade (Grob USA) advised that I clean very well and degrease the adjustment rods (actually they looked more like small flat plates inside the spinner; maybe they're called adjustment plates?) but NOT to lubricate them. He said they work better dry and clean. This fixed my problem. Also, I slow down to about 40 kts. I suggest you try this before going through the adjustment process, of which I have no knowledge. Hope this helps!

Subject: Re: Pitch adjustement of the prop
From: "williamberson" <whodunit
Date: 3/20/09 5:23 PM
To: G109_Pilots@yahoogroups.com

I prefer to shift into high pitch at 65 or 70kts. The higher airspeed helps to prevent lugging the engine.
Bill

Subject: Re: Pitch adjustement of the prop
From: "Ray" <jb92563
Date: 3/20/09 10:32 PM
To: G109_Pilots@yahoogroups.comThe procedure to adjust the prop pitch is very simple and takes only a few minutes to accomplish.

While prop is in Feather setting, loosen the 13mm nut about 1/4" (Hold the bolt portion in its same orientation)till the pin in the top plate can be lifted out of the 12 holes on the facing lower plate.

Once the pin is out of the lower plate you will turn the lower plate CCW to get about 480 rpm increase for each full turn.(40 rpm per pin hole)

Follow the Grob POH for the L2000 to make sure you are getting 2750 rpm +- 100 rpm static in the climb position at full power.

The corresponding Cruise Rpm is 2200 rpm static, also as stated in the POH.

You can not adjust the cruise and climb pitch independently, they both raise or lower together.

I think that if you are getting 2500 rpm cruise in flight it sounds like things are working as designed or perhaps it needs to be slightly higher in pitch, lowering the rpm slightly.

I would check the static numbers to make sure they match the POH.

Perhaps someone else can say what rpm's they get in cruise setting and what the airspeed is.

Disclaimer:

None of this procedure is endorsed by Hoffman and any prop work or adjustments should be done only by a Hoffman authorized firm or as outlined in the Propeller POH.

Subject: Re: Pitch adjustement of the prop
From: "prg55100" <pierrot.greff
Date: 3/21/09 12:53 AM
To: G109_Pilots@yahoogroups.com

Hi Bill, Hi Jackie, Hi Ron
Thanks a lot for these swift replies. I usualy prefer engaging cruise pitch at low speed. It engages well but afterwards the engine needs quite a time to recover the rpm even when pushing the nozze down.
Having red Ron's post I will check again more precisely the static rpm's. In my last yearly checks I had 2700/2000rpm in 04/2007 and 2800/2100 in 04/2008.
Amicalement
Pierrot

Subject: Climb and cruise static rpm
From: "prg55100" <pierrot.greff
Date: 3/22/09 3:24 PM
To: G109_Pilots@yahoogroups.com

Hi guys,
I checked todays my static rpm in both conditions after thorough cleaning (no lub) of the various pieces (4 rods and the plate) inside the spinner.
In static in climb mode I get 2750/2800rpm and 1800/1850rpm in cruise mode. So less than the 2100/2200 rpm expected
Nevertheless in horizontal flight at 2500ft in cruise I get 2600rpm and over 90Kts after a few minutes of transition. I was solo with 60l fuel.

Thanks Jackie the cleaning helped well. Could you please indicate me your own static and in flight climb/cruise parameters?
I would appreciate if some other could indicate their parameters too

Jackie, Ray,
I will try to get in touch with Grob personal to get information on their further G109 servicing and maintenance.
Cheers
Pierrot

Subject: Re: [G109_Pilots] Climb and cruise static rpm
From:
Date: 3/22/09 9:51 PM
To: <G109_Pilots@yahoogroups.com>

Weather was good today for a change so unfolded the wings and played for awhile. Static climb RPM = 2800 in flight 3200+, cruise rpm static= 2000 in flight after a few minutes 2600+ I have not checked the accuracy of the tach! and will have to barrow my son's tach check instrument. Best Paul