Prop Governor and Synchro Slave

hharney · #1 06-10-12, 02:08 PM

The aircraft is a 77 G Model, normal aspirated. The rear prop governor was just repaired by a reputable prop repair station. The repairs were made to the synchro gears and potentiometer. The governor was returned as "good to go". It was overhauled just 200 hours ago in the year 2000 when the prop was OVH. The aircraft Service Manual indicates that this model or type was used on #1816 and on. The aircraft is earlier than #1816 so there is a question as to why this type governor is on this aircraft as it appears to be original equipment. Looking at the figure from the SM the high RPM stop is different than the photo of the unit on the aircraft. The photo from the aircraft appears to have a bent stop screw and is not contacting the stop plate square. The shop says it is ok and that all these governors are like this. It just doesn't look right. Does anyone have a similar governor setup with this Syncro system? Could you please verify the photo and comment.

For those that have prop synch, is it worth the hassle to keep?

Red Air Rambo · #2 06-11-12, 03:44 PM

I like my prop sync. I could live without it but it is nice.

edasmus · #3 06-11-12, 11:03 PM

My shop removed all prop sync hardware in my plane several years ago after I installed new prop governors. Have not missed the system for one single second.

Ed

hharney · #4 06-12-12, 06:52 PM

Ed
What's your serial number? Do you have any photos of the rear gov slave?

Does anyone have the McCauley service manual on the governor?

edasmus · #5 06-12-12, 10:54 PM

Herb,

My serial number is 33701473. When I purchased the airplane in 2002, I spent a few bucks trying to get the prop sync to work properly. Didn't have much luck. Then when I replaced the prop governors a few years ago, (we have had that conversation in previous posts) there was additional costs getting governors with the necessary "stuff" to have the prop sync system function. Well, I had not been using the sync system anyhow and never felt it was worth one penny anyway so I saved a few bucks and purchased prop governors that did not have the "bells and whistles" for the prop sync system.

I am not sure exactly what you want me to photo. I have my old governors and could take some photos of them if that might help you. As mentioned, I do not think my new governors would help you at all.

Ed

hharney · #6 06-13-12, 10:14 PM

The first post of this thread included an attachment from the service manual that depicted the governors, with and without synch. Did yours look like these on the figure? It appears that according to the SM the governor that we have is not suppose to be on this aircraft. Also it has a strange configured max RPM stop and screw. Doesn't look right as the photo attached to the same message is also there. Just trying to understand these units. Where your originals McCauley Governors?

edasmus · #7 06-14-12, 11:27 AM

Herb,

I will dig out my old governors tomorrow night or early Saturday morning and see what can be learned. I will take some photos and attach.

Ed

edasmus · #8 06-14-12, 11:55 PM

Herb,

I have my old governors. They look nothing like your photos. I will post photos tomorrow night when I get my camera.

As far as I can tell these governors came with my airplane in 1973 as McCauley model number CFS310D1A/T1. These units appear identical and have identical model numbers. They were overhauled in 1988 by Maxwell Aircraft Service, INC at the Crystal Airport in Minneapolis, MN and both governors were converted at that time to model number CFS310D1B/T1. I do not know why or what the difference is between the two models.

About 4 or so years ago I tried to have them overhauled again and two shops said NO. The shops were Aircraft Propeller, INC in Wheeling, IL at the KPWK airport and Aircraft Systems, INC in Rockford, IL at the KRFD airport. I did not discover the paperwork on these governors that came with the overhaul in 1988 until after purchasing two brand new governors. I do not know if this Maxwell Aircraft Service, INC is still in business but it might be fun to try and see what they would say about these old governors. I can say they were working normally when they were removed about 4 years ago and have been sitting in my closet ever since.

I will have photos tomorrow night at about this time.

Good Luck,

Ed

edasmus · #9 06-15-12, 11:33 PM

Good news is I have photos. Bad news is they are too large to post. I emailed you two of them. There are more if you would like them.

Ed

edasmus · #10 06-17-12, 10:51 PM

Hey Herb,

I do not know which governor was on the front and rear. It would not matter though because these two old governors that I have are exactly the same. They have the same model number and look identical. As for the prop synch mechanisms (those little tiny gears in your photo), if they were attached, they are not now. Neither of these governors look anything like your posted photos. I do have an electronic "box" in my closet that was removed from the rear engine compartment when these governors were removed four years ago. This box was part of the prop synch mechanisms. This stuff did not function properly and was all removed from the airplane and my airplane is completely void of any prop sync equipment at this time.

Keep in mind that my airplane is a 1973 model and the plane you are dealing with is a 1977 model. It is possible that the entire prop sync system was handled differently in these two 337 models and that you and I are comparing "apples and oranges." I really don't know how these two model years compare in this regard.

If it would help, I would gladly ship you these two old governors as well as this "electronic box" that was removed from my plane and you can compare for yourself.

Good Luck,

Ed

cawelsh · #11 10-04-13, 11:08 PM

I have two matching governors without the little gears. Syncro is via the black box and a parallel driveshaft that lengthens and shortens the rear prop cable a small amount. Trying to find out if the cable, Part # 1550017-8, includes the little piece at the end that is on the prop cable/governor joint that lengthens and shortens? I can't find a separate part number. The little extension bit is internally frozen.

I could use a broken 1550017-8 cable to make a tool to free it up if anyone has one.

Thanks!

Dale Campbell · #12 10-05-13, 10:02 AM

Hi Herb,
I have a 337H normal asperated 1978 ser.# 1824. I can photo my prop gov. if you want it. I will have to drive 20 miles to airport. I had my unit overhauled in 2004 and it failed again in 2009 after 300 hours so I never overhauled it again. I use sound and sync meter on instrument panel to sync by hand. Dale Campbell