Center of gravity
 

I just finished a Big Stik 60. I placed the 70 Magnum 1 Inch closer to firewall and batteries etc. as far back in the fuse as possible. It still needs 6 oz. of lead way back on the fuse. Input

RE: Center of gravity
 

A 60 size plane should have a 90 size four stroke... I recomend a Saito 115:D This should fix your problem. Serious though the Mag 70 will be no more than a lazy circle burner that you would probably have to make a shallow dive just to get a loop out of it.

RE: Center of gravity
 

I hav a 100 saito that is going on it eventually but I am in the beginners forum for a reason. Some some lazy circles and a good aproach and soft landing would be great fun for me. The issue is weight. The 100 saito and 70 magnum are almost identical in weight.

RE: Center of gravity
 

Aside from installing a larger, heavier engine, you could try relocating the rudder and/or elevator servos to the rear of the plane.

RE: Center of gravity
 

Actually the bigger heavier engine would make his problem worse. I have heard of people clipping the nose on stick planes and moving the firewall back so they could put oversized engines on them. I have never done this and it does not make sense to me that you would have to to put an actually smaller engine than what is recomended for this plane.

RE: Center of gravity
 

Put it on it now. That's why we have a throttle. Lazy circles can be done with the 100, too. You are better off with the more powerful engine if you have to add lead.

RE: Center of gravity
 

Move the battery pack to the rear fuselage below the pushrods can be as far back as necessary make a small access hatch on the bottom and use an extension if need be.

For the type of use and flight you are looking for I suggest balancing at the Quarter chord, thats 25% of the chord back from the leading edge.

John

RE: Center of gravity
 

Just finished building one. It too was extremely nose heavy. I moved the Tower Hobbies 75 back 1" and moved both the elevator and rudder servos back to just in front of the tail feathers. The plane now balances with the 5 cell battery under the servo tray and the rx located just aft of the servo tray. This modification also required an additional servo for the nose wheel steering with a Y harness connected to the rudder port on the receiver.

RE: Center of gravity
 

Like doubledee I made similar mods to my Big Stik 40. It is an ARF with a Saito 82 - things changed:<ul>[*]battery box under the rear wing mount block,[*]throttle servo tray (only 1 servo) placed just in front of the battery box[*]elevator and rudder servos relocated to the side and top respectively of the fuse[*]tail dragger[/list]After all said and done it balanced without the use of lead.

RE: Center of gravity
 

You are sure that your CG calculation and measurement is correct, right? It's rare, but sometimes the manufacturer's reccomendation will be wrong.

RE: Center of gravity
 

Thanks everyone for the feed back. I am dissapointed that this turned out to be such a hasstle. This was going to be My Sunday go kick it in slow mode plane. After getting it built I wpouldn't wast one of my "goood engines on this Plane. It is a very flimsy plane. The bulsa is so soft that when I went to cut a whole for the battery switch instead of the "new" #11 sinking in for a clean cut it punched out a two inch piece of balsa. I ripped off the covering and set in a piece of bals from a privious wreck. I hav also just complete the Top flight Cessna 182 with a O.S. 120 Pump. It is not TOP quality but the engineering is very good. I am jus not a good enough piolot yet to have the guts to put this one in the air before I am ready. Thanks again averyone.

RE: Center of gravity
 

Toss the nose wheel and make her a proper tail-dragger. That brings some weight back and reduces drag.

I had the .40 size with an OS 70 II Surpass and it was a great marriage. The model is tough enough even as an ARF. I used mine year round up here in snowy NY. Flew the wings off it - literally. Mine was lost in a midair.