CG ON AEROWORKS 100CCYAK

[john911]

I GOT A 100CC YAK DA100 I'M TRYING TO GET IT BALANCED THEY GIVE ME 3.5" FOR A START POINT.I WENT TO 4"THIS IS ON WING TIP.I STILL NEED TO ADD 10OZ OFF LEAD.I MOVED THE MOTOR OUT1\4".ANY IDEA HOW TO GET READ OFF SOME OFF THE LEAD.THE PLANE CAME IN AT 28POUNDS8OZ WITH OUT THE LEAD.

[Hammerman]

I had an AW 100cc Yak, loved it but also had a tough time with cg. Mine was very nose heavy due the old 3w 120 I had. If yours is tail heavy you may try moving the engine some foward.

[bodywerks]

Where are your batteries?
What batteries are they?
Where is your rudder servo?
How far forward of the cowl is the prop?
28.5 pounds sounds like you either have cans or heavy batteries or extra equipment you don't need...
My buddy has one of these and the CG was no problem at all with a DA-100 and stock mufflers and is in the low 27 pound range I believe. His batteries are about 10" in front of the wing tube and he is running a single pull-pull rudder servo. But his prop is about an inch forward of the cowl, and yours should be as well. spacing the prop forward will noticeably improve thrust on these big round cowl planes and helps with CG.

[john911]

2600 LIT ION THEY ARE NOW AT THE FRIEWALL IMADE SOME EXTTOINS TO GET THEM THERE.THEN MOVED MOTOR 1.5 FROM THE COWL GOT ME MY CG WITH NO LEAD.I HAVE 2 RUDDER SERVOS AN SMARTFLY AN DA STOCK MUFFLERS.

[bodywerks]

You will be fine with the CG at 4 inches. Go ahead and fly it and see how you like it. I am flying a BH 100cc Yak with the CG probably 1" behind where it should be and the plane flies easily and is great for 3D.

[BOSSIER_ROB]

My AW yak (100cc) Was too nose heavy with a DA 100, 1" spacers that gave the suggested gap between the prop and cowl at 1/2". I agree sticking it out more will increase your thrust and you want as much pull out of that prop as you can get. I opted not to move my motor out more because I was trying to shift the CG back a lot. I had a Duralite SC-12 and 2 4cell 2600 Li Ions mounted where the rudder servo pull pull tray was. My ignition battery, a 2250 mAh 2 cell li ion, was mounted just forward of the fuel tank. I ended up adding 8 oz of lead inside the stab tube trying to shift the CG back enough to get it nuetral. I never checked the CG on the ground again. I just moved weight around until it flew like I wanted it to. It still was a tad too nose heavy for me but I sold it before doing any more set up changes to it. You probably wont want the lead your about put in it. If you're anywhere near the suggested CG in the manual, you're fine. It isn't very sensitive to the balance. You'd have to throw a brick in the tail to notice it being too tail heavy and even at a neutral CG it still tracked nicely for IMAC and 3D'd pretty well.

[Geno]

Im flying mine flying mine at 4.25, i have a da on cannisters, but my all my batteries are behind my canopy, running a single rudder servo in the tail and have no spinner. But like bodywerks said, try it at 4 but im sure you will be be around the same as me

[Skippykix]

My 100cc AeroWorks Yak (new red white and blue version) is the only plane I have ever built that absolutley drove me crazy with the CG. I followed the instructions and ended up with 22 oz of lead in the nose to get it where "THE INSTRUCTIONS" said it should be. After the first couple of flights I ripped out all of the lead and slid the batteries back aft of the wing tube and it flys GREAT! Just fly the plane, flip it over on a 45 degree upline and see what it does. If the nose drops fast your nose heavy, if it drops slow your pretty much good to go or if it stays the same or climbs you might be slightly tail heavy. Either way just go with how the plane flys and you should be fine.

[Efishensea]

Putting one together myself right now and have another question…Anybody, Cut the front of the Cowl open a little more to get more air over the Jugs/Heads or is the stock openings fine?? And is anybody gluing in baffling between the cowl and the Jugs to aid cooling?

[BOSSIER_ROB]

I ran mine without any extra baffling or cut out and my motor got a little warm, not bad at all, but I added a bare minimum amount of balsa aileron material to the upper and lower inlets, after opening them up a tad, about 1/4" from both cylinder heads and just boxed in the sides with some thin balsa sheeting. It cooled much better. Performance was noticeably better. I just epoxied the stock to the cowl, the sides to the stock, no glass, or anything else. Give it a try.

[Efishensea]

What do you think of cutting away this part of the front of the cowl on both sides?

[riverfront]

	Quote: Originally Posted by Efishensea
	What do you think of cutting away this part of the front of the cowl on both sides?

put any baffling in first to match the jugs before you make the opening bigger. I just baffled the low side and opened it up a bit, seems to be good. was a little warm before.

[Efishensea]

OK, Thanks! Now back to the correct CG...... I am going wth 4" Back.

Anybody put the Rudder servos in the tail??

[john911]

i was tall heavy with two pull pull servos

[Efishensea]

Yep, Thanks! I'll Keep them in the tray.. I have the DA 100L too. So, in theory she should be light up front....