Electriceddie

Hi Guys,

I have a ESM P-51B Mustang with a DLE-35RA Gas Engine in it. Being fairly new to Gas Engines I understand that to reduce any chance of radio interference that you need to use Non-Metallic type push rods. I have tried several different types of push rods to find the right set up/


I have moved towards the older type of Dubro / Great Planes Nylon Push Rods.
The "Red Tube with the Yellow Nylon inner tube push rod with threaded metal rod about one inch long to screw on a clevis on etc...".I have a 1 inch threaded rod in the end with a threaded ball link attached to it for the Throttle. After several attempts to get the right rod and the right location in the firewall, I have the rod installed for the time being. Nothing is permanent yet.....



My Question is:

I remember in the old days back in the 70's when they were used quite a bit. The problem was when the weather got cold they would contract and when the weather got warm they would expand. Can anyone who has used them recently tell me if the situation still the same? I remember it would wreck havoc on the "Trim Settings" all the time.



The manual suggests using a "Ny-Rod" type set up with small threaded one inch rod ends on both ends and then a ball link on one end and a 90Deg. bend with a Faslink on the other. I know I could use 90Deg. with a wheel collar and several other ideas. But any other suggestions would be helpful.



Also any suggestion with the Choke? It is pretty stiff and some of the Throttle rod set ups would not work on the Choke because it is so stiff.



Note:

• I have plenty of Parts & Supplies to work with. Ny-Rods (Red Tube & Yellow Insert rods), Dubro Lazer Rods (Red Tubes slightly bigger with Opaque white/ Clearish Tubes) , Flexible Cable Pushrods of different size ( 3/64" & 5/64") Braided Copper Wire, Grey Tubes from the GP 48" Steel rods Push rod set ups. Just about any type of end & connector available.

Thanks a Bunch

Ed

samparfitt

My Feedback: (43)

Ed,
I mount the servo on the back or front (if no room in the back) of the fire wall. This keeps the linkages short. Everything is 4/40 with dubro ball link on the servo side and sullivan's easy disconnect ball link on the engine side.
The sullivan ball link makes it easy to remove the engine, the ball links at both ends insures no binding and nothing is vibrating and virtually indestructible versus a clevis pin can brake plus, over time, elongate the hole. On large planes, I think ball links should be used, exclusively, on all moving surfaces and servos.
http://www3.towerhobbies.com/cgi-bin...?&I=LXYCH4&P=7
I've had plastic gear brake so I use only metal gear servos: I over kill and use HS-645's (they're only 30 bucks each and not worth saving a few bucks putting in a cheaper servo: nothing more sphincter tightening that having a dead engine on a warbird).
The fire wall is made removable so the throttle/choke servos can easily be set up. The choke always gets a servo so I can control the engine on a full throttle engine servo failure (which I haven't had yet) or gear won't lock and I can kill the prop before a belly landing (thus saving from braking a 70 plus dollar prop, which I've had a few.).
I haven't had any problems (radio wise) using all metal linkages for the choke and throttle and, with very short linkages, there is no thermal problems. I think that's old 72 MH day problems.
If you have to use the sullivan Ny-rod, it should also work great: if there is a thermal expansion, the throttle trim will take care of it (if it colder than 60 degrees I ain't flying!).
As for a stiff choke, I've never had any problem with the 133 oz HS-645 moving the choke and I use DA, DLE's, 3W, Zenoah and moki's.

Sam

Electriceddie

Hi Sam,


I am running on 72Mhz. I do not have any access to mount the servo behind the firewall which I would like to do. It is totally concealed., so I have to mount it in the fuse area below the wing. Its a P-51B Mustang. What about the metal on metal for interference. ? I believe its OK as long as I break up the path with a Nylon push rod in the middle of the run, right?

Thanks

Ed

samparfitt

My Feedback: (43)

Ed,
Can't say on 72MH, been too long since I used it. Do a range test with engine running and rotate plane 90 degrees for each test doing a full 360 for a total of 4 range tests.