Can anyone help me with this problem..i have a yak 54 by seagull with a 26cc crrc gas.....there is a prob with the CG from what i here
it is wrong in the hand book, it says from the tip 7 to 8 cm..I here this is wrong and makes it tail heavy..then i here its 5.5 inch from leading edge then i here its 7 to 8 cm from leading edge near the fuzz..
which looks far too near the leading edge, i dont wanna get this wrong for her first flight i need the correct CG for it..some threads say it dont fly if its on or near the alloy tube which is where i would have guessed
it would have been..also it has a 20oz tank, do i CG with it full half or empty hope you can help many thnx</p>

I'll answer the last part... I've never heard of a plane where the CG should be adjusted for a wet condition (with fuel). Also, 20oz is a large tank for a 26cc gas plane. I'd think 12oz would be more appropriate and I say that from a safety perspective. If something happens to throttle and the plane has to be flown until out of fuel before landing... 20 oz of fuel is going to be a very long time. Probably 30-45 minutes and if at lower throttle setting, perhaps even an hour and if it is on a later flight of the day, battery life or daylight might be an issue.

There is a long running and current thread on the Seagull Yak so a search of it might produce your answer or a post there might catch the attention of the guys flying that plane.

thanks for that i will change the tank i thought it was a big big lol..yeah CG you get 5" to 7-8 cm from leading edge..i would go with the 5" makes it around the 1/3 mark and near the wing tube

COG is rear of wing tube, mark it on the fuse and balance with the canopy on, it weighs enough to make quite a difference to the COG. Oh always balance with a empty tank.

Do you have one of tHese Raydar? How does yours fly? What engine do you have? I have DLE 20 in mine. Have not maidened it yet.

Had one, yellow and black version, had rcg 20 in it, same power as dle 20 (I own a dle 20 also) I sold it to fund a 26% yak.

The plane flys great and infact mine still does for another pilot with one hundered plus flights, 20 cc is perfect for it. Its not a great plane for 3d due to being a bit heavy but it flys acro great. The CA hinges WILL fail with a gasser, do not use them, upgrade to pinned hinges. There is a hugh thread on this model you should post on it as all the info you need is there.