gelandestrasse

Hello, I just received my Yak this afternoon, there is nothing in the instructions about the CG placement.

tallboy33

Same here Nitro Planes Yak 54 56"version 2. Emailed Nitro Planes and they said to ask Jose on RC Universe. JOSE! What is the CG for this plane?

gelandestrasse

I have instructions from the 55" version, but dont think it would apply. I really like the looks of the plane, looks like a small version of my big QuiQue yak, but instructions are really lacking.

tallboy33

Nitro Planes doesn't know what the CG is. They said it's not their problem. I guess when they are out of business, then it will be their problem. I wouldn't recommend them to anyone. They said to ask Jose on rcu. LOL. Anyone know Jose?

Let me know if you know the cg or who Jose is. Thanks.

gelandestrasse

Wow! I cant believe they said that......I have no idea who Jose is, If i find anything I'll post it

tallboy33

They were not helpful at all. They said their job is to sell planes, not give build support. I said I didn't think CG was build support, but critical specs on the plane.

Post #8 on this thread says the CG should be 4.7 inches from leading edge. I'll go with that for starters Sounds like the same plane. I know there are 2 or 3 variations of this.
www.rcuniverse.com/forum/m_8127559/anchors_8127559/mpage_1/key_/anchor/tm.htm#8127559

Let me know if anyone figures out who Jose is.

gelandestrasse

Hey thanks, I'll give that a shot too.......... I hope I dont have the same problem I had with my first version, I did a blender and ripped the horizontal stabs off (both sides) i think I'll brace these with carbon rods.

opjose

Yak's typically have their C.G. at about 20-25% of the wing root chord MAC.

Anything at this or in front will be safe.

On a new Yak I start at 25% and I may work the C.G. BACK ( SLOWLY about 1/4" at a time! ) to about 33% for 3D stuff.

If I note that the plane seems to want to pull up as I am trying to land, I'll move the C.G. forward.

gelandestrasse

Thank you for the info.

tallboy33

Thanks for the info on calculating cg. Much appreciated.

gelandestrasse

Hello, flew the yak this morning, CG was at 4 3/4" back, which was way safe, and could definately be a little further back.

cbh82v

My Feedback: (2)

Thanks for posting. Did you adjust the cg from 4 3/4? Where did you end up? Did you have and lateral ballence problems? I'm about to maiden the same plane. I'm starting at 5 1/4. Also, Howare your control throws set? Are you using any expo? Any additional info would be awesome. thanks.

dryfly2u

Ive got a new yak 54 56in wingspan version 2. We got it put together and the cg on it with the batt. moved clear up to the firewall is 6.25 back from the leading edge of the wing measured parallel with the fuselage. As with you guys no specs. in the instuctions if you can call them that. The plane is a beautiful plane and fit together well. We had to beef up the elevator connection between the two initial halves with a small piece of hardwood and we changed out the rear tailwheel with a little bit different assembly but as a estimate I would say we added 14 to 28 grams to the tail section of the plane. Wondering how many ounces it would take in the front to make up for 14 to 28 grams in rear, if its twice as far does it take half as much weight? If I have the batt. forward clear to the firewall I still have to add about 8 ounces of lead to the firewall to get my cg to 5 in. back from the leading edge. Im a bit scared to fly it at the 6 inch mark and hate to add 8 ounces to the plane to get it to the 5 inch mark.
Not sure what to do but really dont want to crash it trying to land it tail heavy, Id appreciate your or any advice for that matter.
Oh and also we did our checking of the cg in the inverted position.

cbh82v

My Feedback: (2)

I've got 15-20 flights on mine now. I ended up with a CGat 5 1/4 inches. It flies well on that CGyou could goa little more aft but notmuch. I'm running an ASP 52 mounted as far foward as Ican get it and it ballanced without adding weight.I'm running a 12/4 prop on the ASP52 and getting 12300rpm with the needle set 200rpmrich of peak.. A 12/6 was not letting the motor get much RPM. I have have not tried a 12/5 but i will. The plane does well on the ASP52 and will do unlimited vertical. But it could use more power. If your having cg problems i would put a 60 on it. I talked to a guy at the field that had a 90 2 stroke on the old version. My aleron throws are 15mm on low rates, elevator is at 40mmon low rates. I'musingall of the throw i can get on the rudder, around 100mm I tried 50mm to start and it needed more rudder. I'malso running 25% expo on all surfaces.
Ihaveheardof people having problems with elevator flutteron theold version. I put hinge tape onall of my control surfaces. I was also running a standard servo on the rudder and I had to change to ahigh torqueservo and a 6V battery pack.

hope this helps

dryfly2u

Yes very helpful, thank you.
Me and a friend who by the way has done more work on my plane than I have took it out today. It was very windy so didnt fly. I added a bit of weight and put the cg at 4.75 just to be sure. I hope to take some off after Ive flown it but we will see. It weighed in at 6.25 lbs with the tt.46 and a pitts muffler, not sure where they got the 5.2 lb advertisement but it is what it is. I think it will fly great if I can get a day with at least alittle bit softer wind blowing and then of course the nuts to get it off the ground for the first time. I have been thinking of a larger motor if this one is underpowered but the tt .46 I beleive puts out dang near as much power as a .60 (probably depending on the 60) with less weight. It would relieve some of the balance issue in the plane going to a bigger motor. Its funny the ad for the plane said I believe a .52 for the plane, the box that it came in said .46, it will be interesting to see what it really needs. We beefed up the rear elevator half connection point on this one with a small thin dogbone shape piece of hardwood epoxied on the top of the elevator joint. It required a little cutting on the slot that the connection rides thru but it sure is a heck of alot better on twist. It transfers the torque from the airhorn alot better to the other half of the elevator relieving the pressure on the original elevator connection. We also installed real hinges for all control surfaces.
The low rate numbers sure seem small to me but by the same token Ive never flown a plane with such large control surfaces before. I have everything maxed out as far as throw goes, about 50 degrees on the elevator and rudder. The ailerons are at about 35 to 40 degrees. Then I have them turned down to about 70 percent on high rate and 30 percent on low for ailerons, 45 percent on low elevator. I will see how that comes out on actual throw in the morning. I can increase my throws another 5 or 10 degrees by bumping my end points up on the radio but I am not sure if that will be needed or not for the 3d.
I dont have any expo in it yet but have been discussing it alot, I think we will go with the 25 percent that u mentioned for now, ive never used expo much but it seems like it could do nothing but help.
It is good to hear that yours is flying well for you, congrats!
Alrighty then, time for bed. I appreciate the help and will let you know how it goes.

dditch

My buddy has the 56" yak 54
He mentioned he fuel proofed the front firewall and wood area.
He also said he did not mount the fuel tank as far forward as he possibly could and had to put a pump on his OS55
He bent his gear some with a hard landing when he first got it but bent it back.

Are you guys getting a manual but it does not list the CG or just no manual at all?