110" TIMBER Assembly Thread

john Derstine said:

CG consideration. Getting to the point where I can begin to check the CG location. The instructions are wrong, and most always err to nose heavy for safety reasons. Read about Nick's re calculation through trial and error to a reasonable CG.
There is really a good way to check and verify if your CG is safe and what kind of handling you will get with a given CG, but you have to know the neutral point of the aircraft or you are just guessing, most of us with experience get pretty good at guessing, but I always calculate the NP before I decide on a CG. If you don't know, the NP is the point aft on the main wing from the LE at which angle of attack has no effect on pitch, the plane is aerodynamically balanced. The CG is a center of mass calculation only. Static margin is the distance between the NP and the CG expressed as a %. CG is always for our purposes forward by a % of the NP. 7% to 10% is considered a middle ground for static margin on a conventional aircraft. less becomes twitchy, 15% becomes mushy.
I can usually guess a constant cord wing simple plane will balance at about 33% of cord. on the Timber I went conservative and guessed 30% which equates to 4.75 inches. I then ran the calculations for the NP and it more or less confirmed my guess, but It also can give me the static margin so I know what to expect. Long story short using a 7% static margin (on the crisp side) the CG calculated to 5.03" from the leading edge. (1 " ahead of the NP) using a more conservative static margin of 10% the CG came out to 4.63" The actual NP calculated to 6.03 " which is the point where any more Aft CG will result in an unstable aircraft. If you want to try this yourself, there are several online calculators that take the math out of the job.

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AKNick said:

5.125” is a good spot

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john Derstine said:

thanks Nick, I read that in your set up, that's what's nice about a forum like this you can get real feedback from other pilots.
I am always checking the parameters and theoretical flight envelope on planes out of habit from designing airframes in my past life. The up shot is every example is a little different and pilots vary on how they like planes to fly. I guess I should have added for future reference it I always nice to have tools before that first flight especially if you don't have the added value of others experience with that airframe. The NP on the timber is extremely far back at 46% of chord, typically on a plane like this 38% is more likely, this just means the Timber has an extremely wide CG range from around 5.75" all the way to around 25% f chord or around 3.5". (not that it would be enjoyable at the extremes)
I'm going to do first flights at 4.75 and adjust from there, I don't plan on doing much 3D. we will see how it goes, getting pumped now, radio is being delivered today after being held in customs for a week , and the spinner.

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AKNick said:

@Snoopy1 and I found put that going past 5.25” the plane doesn’t handle well. Post stall is not that good, and just a tad more touchy. FWIW 5-5.125” is ideal. With fuel it doesn’t change much if your fuel tank is backed up near the rudder servo.

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john Derstine said:

cowl is now fit kinda, I have to trim the cowl to fit properly, and/or I'm probably going to have to shim the engine out a bit more. But the beautiful JR radio came today, the first good premium set I've had in 20 plus years. charging for 3 hours then some playing to take place.

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ChelseaDan said:

After an 8 month wait for a maiden I got it in on Sunday. Late fall here didn't provide any decent days for a maiden - life got in the way until last Sunday when I finally got my Timber to the field. DA-50 for power. Hitec 5645 servos all around - even for throttle and choke. Another club member flew his late last summer and I saw how the standard LG was junk so I ordered the XCub gear - glad I did. While I only got two flights in Sunday, I can say the plane met all the expectations I had. I started with the UMX Timber for indoor 3 years ago, moved on to the Turbo Timber and then bought the Timber 110. The DA 50 has more power than needed - at half throttle in knife edge, it has enough power to make it climb. Flight characteristics are rock solid no matter what you do. Pull the nose up and you can hover it. Flaps really do the job. Next up is to dial everything in. Right now I have all the max throws where I want them along with the expo I like. Given it stays like that, I will then mechanically adjust the linkages to maximize servo throw. I'm going to start mixing down elevator to the flaps. I do believe this will be my go to plane the rest of this season. While I didn't get any pictures of the maiden flight, my good buddy AJ did with his drone. Here is what AJ captured :

. Will post more about my impressions and experiences with the Timber as I get more stick time. What I can say now is that it is a winner.

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ChelseaDan said:

After an 8 month wait for a maiden I got it in on Sunday. Late fall here didn't provide any decent days for a maiden - life got in the way until last Sunday when I finally got my Timber to the field. DA-50 for power. Hitec 5645 servos all around - even for throttle and choke. Another club member flew his late last summer and I saw how the standard LG was junk so I ordered the XCub gear - glad I did. While I only got two flights in Sunday, I can say the plane met all the expectations I had. I started with the UMX Timber for indoor 3 years ago, moved on to the Turbo Timber and then bought the Timber 110. The DA 50 has more power than needed - at half throttle in knife edge, it has enough power to make it climb. Flight characteristics are rock solid no matter what you do. Pull the nose up and you can hover it. Flaps really do the job. Next up is to dial everything in. Right now I have all the max throws where I want them along with the expo I like. Given it stays like that, I will then mechanically adjust the linkages to maximize servo throw. I'm going to start mixing down elevator to the flaps. I do believe this will be my go to plane the rest of this season. While I didn't get any pictures of the maiden flight, my good buddy AJ did with his drone. Here is what AJ captured :

. Will post more about my impressions and experiences with the Timber as I get more stick time. What I can say now is that it is a winner.

Click to expand...

ChelseaDan said:

After an 8 month wait for a maiden I got it in on Sunday. Late fall here didn't provide any decent days for a maiden - life got in the way until last Sunday when I finally got my Timber to the field. DA-50 for power. Hitec 5645 servos all around - even for throttle and choke. Another club member flew his late last summer and I saw how the standard LG was junk so I ordered the XCub gear - glad I did. While I only got two flights in Sunday, I can say the plane met all the expectations I had. I started with the UMX Timber for indoor 3 years ago, moved on to the Turbo Timber and then bought the Timber 110. The DA 50 has more power than needed - at half throttle in knife edge, it has enough power to make it climb. Flight characteristics are rock solid no matter what you do. Pull the nose up and you can hover it. Flaps really do the job. Next up is to dial everything in. Right now I have all the max throws where I want them along with the expo I like. Given it stays like that, I will then mechanically adjust the linkages to maximize servo throw. I'm going to start mixing down elevator to the flaps. I do believe this will be my go to plane the rest of this season. While I didn't get any pictures of the maiden flight, my good buddy AJ did with his drone. Here is what AJ captured :

. Will post more about my impressions and experiences with the Timber as I get more stick time. What I can say now is that it is a winner.

Click to expand...