I am designing a 1:8 scale model of the Do-24T seaplane. It has three engine and no rudder for when it is on the water. What is the common practice on mulit-engined plane do all engines work off the same throttle control channel or can you have port and starbord engine throttle control?

If you had a transmitter with mixes available, you might be able to mix rudder to an outboard engine throttle channel. Just a thought.

why won't you have rudder when it's on the water?

Or, if you make it an electric you can mix differential throttle using two seperate speed controllers, Oh I see you need THREE!

Unless you are intent on some super accurate scale model I would just take the simple route and rig a water rudder, right where the hull starts that sharp upsweep. Russ Farris

P.S. Jetfxr, unless it is dead calm a seaplane will weathervane at taxi speeds and you need either differential power or a water rudder.

If you have enough channel could you do a port and starboard engin throttles And mix they to control the center engine? I am new to the RC world, although I have built many model and done some free flight and control line flying.

Design,
If you look into the Twin Synch manual you will notice that there is an option to slave the port and starboard throttle servos to the rudder at (if I recall correctly) less than 40% throttle. When this option is selected on the Twin Synch board, at less than 40% throttle, as you operate the rudder, the left and right engine throttles will advance or retard and let you steer by differential throttle control (just like the full sized aircraft). Above 40% throttle (or what ever throttle % you choose) the rudder / throttle slave function is disabled and the port and starboard engines remain synched.

I know this option exists because my buddy flies a Ziroli Twin Beech with this option selected. Where once his take-offs were very exciting (the steerable tail wheel is fairly ineffective on a Twin Beech), the rudder slaved throttles tame the Beech takeoffs to a very manageable condition. This setup also helps him in taxiing the model and its kinda cool to listen to the throttles come up and down on different engines (like the real aircraft) while taxiing.

You can find more info on the Twin Synch system here: http://www.rcshowcase.com/html/acces.../twinsync.html.

And now the disclaimer. I am in no way associated with either RC Showcase or the Twin Synch manufacturer. I have however helped my buddy, a Beta tester for the system. If set up properly, I think the Twin Synch will get you what you want. I'm still not sure what to do with the middle engine throttle however, but at least you have a place to begin.

Hope this helps.

Regards,
langerl

Rats,
Bad link. Try this. http://www.rcshowcase.com/html/acces.../twinsync.html

langerl
Sorry I missed your reply, thanks that looks real promising!
Charlie

I am the designer/supplier of the Twinsync. I also have a unit for four engines (quadsync). The quadsync can be used on three engine airplanes as well. This will let you do rudder steer on the two outboards but the center engine will be synchronized to the average RPM of the two outboards. The quad sync is only sold direct (from me). Just PM me.