acdii

Istarted my Kadet LT40 today. What Idid was weigh every part first. The ribs, the spars, the LE and TE. Then I put similar weight ribs in one pile, and started splitting them into two piles, left and right. Next Iput the heaviest ribs in towards the root, with a medium weight rib as the very last outboard rib, you want to do this since the last rib takes a beating from ground contact. Next I took the spars and LE/TE and balanced them out so that left and right were as close as possible in wieght. Between the ribs and spars/LE/TE, both wings were as close as possible.

Imark each piece with its weight. Now Itake the muffler and weigh that. Now that Ihave all the parts marked I can transfer enough grams from the right wing set to the left wing set. Once done the right wing and muffler should be as close to the left wing in weight so when completed, the lateral balance should be very close. With the ribs wieghed out, with the heaviest towards the center of the plane it will also help in roll rate.

The Ailerons and if you have them, flaps should also be weighed and included in the build.

Hope this helps you build your wing well.

91zulu

My Feedback: (2)

Are You serious ///[X(] Wow you gram hogs are way ..way.. over left field. Sir for the most part on a Kadet one wing an oz or 2 heavier than the next is no big deal. Really it isn`t. Unless you are doing it for the fun of it or some sort of experiment to collect data of some sort. Other than that you wasted a lot of time. Just build the thing and go fly it.

mikegordon10

I hate to say it but you obviously have way too much free time on hand!
There may be a model or two out there that might benefit from this treatment but a LT 40 just ain't one of 'em.
With that said enjoy your build and do it any dang way that pleases YOU.

karolh

All that with a Kadet LT40, you gotta be kidding me. Anyway as the say, " different strokes for different folks ".

Karol

acdii

Cmon guys, This tip is for ANY model, especially a Pattern or Sport plane. I just happen to be building a Kadet.   If you dont balance your plane laterally, then you dont need this tip.  If you are building a pattern plane, or sport plane and want to balance it out as close as you can, this is a great tip.  <div>
</div><div>Then again, if you LIKE to drill holes and fill buckshot in a completed wing, go right ahead, enjoy your build! </div>

HighPlains

My Feedback: (1)

I can tell that you are a discerning builder, and imagine the entire airframe is built with well fitting parts and minimal glue. You can build for me anytime.

That being said, I never attempt to account for the weight of the muffler, as it's moment arm is small, and engine torque tends to offset it contribution in the air.

acdii

Thats true, but every little bit helps down the line.  For kicks I held the motor at its center point without the muffler and it held ok, could go either way, but with the muffler added to it, it definitely swung heavy on the muffler side.   On 4 strokes, the muffler is pretty close to the motor, but on some 2 strokes the muffler sticks out quite a bit, and this is where my tip comes in handy.  If you run a larger muffler or tuned pipe off to one side or the other, it also helps. <div>
</div><div>Now had I not weighed these parts and just started building, there was a very good chance I could have put all the heavy pieces on one wing and it would have been 4 ounces heavier than the other wing. Couple that with having the heavy wing on the muffler side and it could be quite noticeable. There was that much difference in the materials.  The trailing edge pieces were a 1/2 ounce apart.  On a pattern plane, that can make all the difference between a roll in one direction to the other. </div><div>
</div><div>I have my left wing assembled, and I must admit, SIG makes a good kit, the wing is exceptionally strong with the I beam type main spar. It went together quickly, all the parts fit snug, very little trimming was needed. The only thing slightly off were the plans to the TE, but the manual noted that could happen. </div>

91zulu

My Feedback: (2)

Oh yes, Sig made some of the best kits, just they require lots of carving in the front and wing tips. The Kadet is a very good trainer. I had a couple of them, made one into a low wing, removed some of the dihedral and is was one of the best flying planes I had. Looked like a Piper Arrow. Had a Fox 45 with a moose can on it. The note that came from that engine was the sweetest sound.
Enjoy your build and when you fly be careful of the wind close to the ground on those hot days. It will get bounced around especially if you fly off a black top.

speedracerntrixie

My Feedback: (29)

Acdii, I like your style. This BTW is common practice with the CL stunt crowd. I almost never do built up wings anymore but when I sheet a foam core, I weigh the wing skins and make every attempt to keep the wings the same weight. After sheeting the first wing, I weigh the epoxy I have left over, subtract from what I had mixed and then apply that exact same amount on the next side. Keep building this way. Soon guys will come to you to confess they had the same kit but it didn't fly nearly as well as yours and wonder why.

kenh3497

+1

kenh3497

+1

Avaiojet

No one has ever asked me about the weight of graphics.

Charles

91zulu

My Feedback: (2)

You guys are nuts. I could understand building an Ultralight or Light Sport that you will be in the cockpit. Now for RC its nuts. Now unless a wing could some how end up a pound more than the other, well I could understand. But each his own.

scale only 4 me

My Feedback: (158)

If you want to be extremely precise,,
Why not hang the engine inverted at the angle it will naturally balance, if you don't like running it inverted you could rotate it 180 degees after that and it wil be right on the money

acdii

Then again, why bother balancing a plane at all. Just stick together and hope it flies. So what if it's nose heavy or tail heavy, or it tends to roll to one side because a wing is too heavy. Just because it is an RC plane doesn't mean you shouldn't balance out the plane in both directions. Wing balance does affect roll rates, it will tend to roll faster on the heavy wing than on the light wing, so if you want equal rolls, you need to balance the wing, and so it took me 30 minutes to weigh out my parts. How long will it take to add weight to the light wing once you have it all covered? At some point you are going to be spending time balancing the plane, why not make it easier to do when you are actually building it?

kenh3497

That is one heck of a good idea. I'm glad I thought of that.........




Seriously, that is a really good idea.

Ken

jaka

Hi!
You are correct!
Build it with weight in mind and balance it while you build and you will have a much better flying plane. That's how pylon racers do it!

When I built my Marutaka DC-3 I removed all heavy wood or replaced all heavy woodparts to reduce weight as much as possible. Every gram was considered. My goal was to build it to 3000g (3kg) but in the end the plane weighted 3600g (3,6kg) ready to fly! Still it flies like a trainer or 2m sailplane. Saved between 400-1000g by being very careful during build.

acdii

My wing is done, except for the Ailerons. Here is what I did, you can see the marks on the ribs, simple, straight forward and took only 30 minutes.

Luft-Gangster

I have not seen the use of the word WASHOUT! ( it is a twist in the wing from root to tip, usually 1 to 2 degrees ) Makes the aircraft stall start at the root and not at the tip of the wing. Much easier to recover from than a tip stall. The aircraft will drop its nose in this stall rather than a wing tip. Don't confuse this with PROPWASH as others have. Just my .2 cents worth.

KitBuilder

I weigh the wood with my gram scale and split it up with heaviest toward the middle but I don't go crazy about it. The longer the wing the more advantageous this is. I find I rarely need to lateral balance and then it may be just a pin I stick in the tip post covering.

acdii

That works too, it was what I had first planned to do, then thought about the extra weight on the right side from the muffler and decided to offset the wings.   I completed the wing yesterday and put the muffler on the right wing near the root, and the wing balanced out good.