Propeller Governor Cable/Engine Baffle

Discussion in 'Pitts Miscellaneous' started by garyg, Mar 12, 2018.

Help Support Biplane Forum by donating using the link above.
  1. Mar 12, 2018 #1

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    For engine baffling I am using a RV-10 kit, which mostly fits pretty well. I have a narrow deck case so there is a couple of differences from the kit and the engine. One is a missing hole in the case for attaching a baffle (I have found on-line threads where some RV owners discovered this and DRILLED holes in assembled engine case and threaded the hole only to find the case very thin there!!! You really have to watch some of these RV builders closely.....). I made new brackets to fix but there is a slight problem with prop governor cable.

    The baffle kit comes with a prop gov cable bracket that attaches to the left front baffle plate allowing the cable to come from underneath. This looks like the best way to route the cable but it also presents a dilemma. I can use that bracket except for the following issues:

    I need to have the gov both re-clocked and the have the gov set up for CCW direction. Whirlwind has stated this is not a problem. I need to re-clock it no matter what I do anyway and:

    Apparently RV designed the bracket to use a prop cable with 2.5 inch travel. A standard 1760 will not work. I need a non-standard length anyway but ACS wants 190 for custom length and custom RV travel of 2.5 inches. At this point 190 doesn't bother me much, so maybe the best way to go. Just figuring out exact length and waiting for the cable. I think this is the best way but I ask anyway.

    or I could use a Cable Safe II (http://www.aircraftspruce.com/catalog/appages/cablesafe2.php) combined with a wire grip (http://www.aircraftspruce.com/catalog/appages/wiregrip.php) and then use a standard 10-32 cable bearing end and just use a solid wire vernier prop cable. This would allow me to use the RV kit without a custom assembled cable. The length of the set up might cause baffle seal issues as well. Is this a good set up to use otherwise? This would make my life much simpler but I am concerned about cable flexing as it goes thru the arc on a 1.5 Radius arm. Long term will it hold up as well swivel ended pre-made cable?

    The S2 A/B/c? uses a bracket that apparently goes between the case and the head and attaches the cable to it and comes over the top of the cylinders. (Aviat wants a whopping 350 bucks for the bracket fyi). They use a different governor and I am not sure this style will work with the Jihostroj governor but maybe ok with a custom design. Big thing is I need to elevate the cable to come down at an angle due the short radius arm on the governor. And does a bracket like this have to be special to expand and contract with the engine when going between the head and case? Maybe why it is 350?

    Alternately, I have seen some create a bracket across the pushrod tubes using adel clamps. I would also need to elevate the cable to come down at an angle. This one bothers me a bit. Is this reliable? using both adel clamps and pushrod tube tubes?

    Engine baffle kit also comes with two plates to block the front cylinder head cooling fins. It only covers the front cylinder head fins near the baffle and not all of them. This would seem to make sense to keep the front cylinders from staying too cool while the back ones are comfy. I don't often see this kind of plates but I have seen them on a couple of aerobatic planes. I am inclined to install them unless informed that they create issues. I would think all cylinders evenly warmed up are better than cool ones. I can always remove later.
     
    Last edited: Mar 12, 2018
  2. Mar 12, 2018 #2

    Dave Baxter

    Dave Baxter

    Dave Baxter

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 15, 2007
    Messages:
    1,563
    Likes Received:
    732
    Gary this is what we did on my sons Starduster. It has a IO-540 G1B5 angle valve engine. I also bought the baffle kit from vans, for the IO-360, and just made a center extra baffle, as they did not have a kit for the six cylinder angle valve engine, back then. We also had the governor re clocked to match the instalation.

    I did not like using the wire cable or trying to route the cable under the engine and coming up from the bottom, so made a bracket that bolts onto and through the mounting screws for the baffle, it does have one adel clamp attached to the push rod tube, but has very little load, mostly to stabilize it and not be fully cantilevered.

    I also lengthened the governor control arm , to match the approximate throw of the military throttle quadrants, and did the same with the fuel servo and mixture control arms, then had cables made up from the local speedometer shop that makes PTO cables. Just don't tell them it is for an airplane, tell them it is for an off road vehicle! It has flown this way for over 10 yrs and 500 hrs. Gary when I did this for Dan's airplane it cost about $ 45.00 bucks for each cable, and just recently had a similar cable made for my trim system on my SA-100, and it cost about $ 90.00 bucks, almost double from 10 yrs ago!

    Hopefully this all makes sense. Dave

    DSC10353 small.jpg

    DSC18822 small.jpg

    DSC07160 small.jpg

    DSC07162small.jpg

    DSC07166 small.jpg

    DSC07167 small.jpg

    DSC07170 small.jpg

    DSC00355 small.jpg
     
    Last edited: Mar 12, 2018
    Larry Lyons likes this.
  3. Mar 12, 2018 #3

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    Dave,

    Thanks for the pictures! I always like pictures. Bracket looks pretty good. I am not sure I can put an extension on the arm on this governor but I am going to look tonight to see if I can make a similar bracket using the arm as it exists. Got to thinking about one of those wire style and there isnt much to prevent fluids and the like from traveling back down the wire opening in the cable housing. So now down to bracket and custom cable or RV custom cable.

    The RV-10 kit has baffling around the flywheel but it doesnt go tall enough nor long enough at the upper frt edge. the RV-10 cowling takes a couple of dips right there. So when I complete the bowl I will probably make the bowl come out to the baffles with a fiberglass plate formed inside it rather than replace or modify the baffles.
     
  4. Mar 12, 2018 #4

    Dave Baxter

    Dave Baxter

    Dave Baxter

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 15, 2007
    Messages:
    1,563
    Likes Received:
    732
    Gary, I only added the extension to make the military throttle travel work if you have something different throttle or travel wise with less travel, then you would not need the extension. Dave

    DSC10026 small.jpg
     
  5. Mar 12, 2018 #5

    garyg

    garyg

    garyg

    Well-Known Member Lifetime Supporter

    Joined:
    Nov 3, 2011
    Messages:
    594
    Likes Received:
    89
    Dave,

    Right, yeah I remember reading that part now I tried one of those 12 dollar RV cable brackets but it looks like it is meant for 4 cylinder engines. They could have reversed a detail or 2 and made it fit a 540.

    gjg
     

Share This Page