Build question - DA 35 to 71 slick

[Rookie 1]

Please comment on optimal set up for CG. I'm in the early stages of the build, but this combination of engine and plane appears to be extremely nose heavy. Appreciate your comments.

 

[SnowDog]

I have a 71 Slick with an OS GT 33 and I did not have any problems with CG...ignition battery is on motor box, RX battery is behind wing tube. I can't imagine the DA-35 is much heavier than the OS GT 33, so I can't image you will have any problems. I did mount a small plywood tray behind the wing tube so I could secure the RX battery either closer or farther away from the wing tube.

One other idea is to make sure you use the shortest standoffs possible.

Why do you say that it appears to be nose heavy in this early stages of the build?

By the way, welcome to the forum! We're glad that you're asking questions and we're happy to help.

 

[Rookie 1]

Thanks for the reply. To clarify - After having assembled the plane up to the point of testing CG I took it out to the airfield to have the experienced pilots take a look at it. It was at that point testing nose heavy for CG. I am now in the process of making several changes per their suggestions so obviously going about this the wrong way. They did suggest moving the battery tray farther back as you have done. One other idea they had was to move the rudder servo directly across from elevator servo which will make a big change in the balance and eliminate the pull/pull system. What do you think about that? Your engines weight is very close (within 2 ounces) of the DA 35 so good to know you don't have any balance issues. Thanks.

 

[SnowDog]

glad you have some experienced pilots to help. and don't worry - we all learn by doing things the wrong way. Trust me when I say it is better to find a plane is tail heavy BEFORE you take off! I know you said yours is nose heavy...I'm just using this as example of my own "learning" path.
You *could* switch the pull pull for a push-pull setup (servo mounted across from the elevator servo) but you don't need to. Moving the battery back should be enough.
One other lesson I have been taught is to make only one change at a time. I think you will find that moving the rx battery behind the wing tube will be enough.

 

[AKNick]

I have a 71" slick with a DLE-35RA, Pull-Pull, A123 Battery (1100IGN, 2300RX) under the turtle deck, Throttle servo as far back as I could put it, One elevator servo, Dual Miracle Switch up front with fuel dot., and a 16oz fortitude fuel tank just in front of the tube (basically touching). When doing the 45 degree inverted climb at 3/4 throttle it barely climbs indicating a tiny bit tail heavy. With that said, the plane does not balloon on landing, it actually feels as if the plane is still a bit nose heavy. I may re-try this inverted test once I get my new cowling on it (old one vibrated itself apart after 7 gallons...) Then I may do a static balance with a 1/4 full tank. Just my 2 cents