m4x pow3r

Hi,

I just put together a "79 yak arf with a Moki 2.1. It balances right behind the wing tube. My question is would it be ok to make a battery hatch toward the tail of the fuse right above the servo wire channel or would this weaken the fuse? I thought about cutting off the top balsa, hogging out the foam and running the battery wire in the servo channel. Good or bad idea?

Thanks

STLPilot

My Feedback: (21)

Your idea has been done many times. I will not reduce the integrity of the plane. Have at it!

Absolut Yak

My Feedback: (4)

Here is a pic of my Edge with an aft battery pack. I did exactly as you described. Note the hatch forward of the rear servo group, under the red OMP logo. My hatch is oversized so I could tweak battery position fore and aft for cg by flipping the hatch/switch/battery position. My battery is in the forward position with the switch mounted on a ply hatch aft of the battery. In my current setup, MVVS 2.15 gasser with MVVS header and pipe, my CG is too far aft. I fly like this all the time, but really need a more neutral CG, especially on landing. Really helped me learned to hover though. I used the front battery position for my ignition battery and switch. My suggestion is to assemble the plane with all components, then place you battery on the fuse top and slide it fore and aft until you get the CG where you want, then cut your hatch location based on this. Worked well for me and I got a spot on per plans CG. However, changing from the Bisson muffler to the MVVS pipe changed the CG a lot.

Doug

Jaco

Thanks for the replies and pic. Sharp looking plane. I think I'll take your advise and fly it first as is, then add weight till I get the right cg, then take off the weight and i'll know where to put the pack.

I got blind nuts for the 6-32 wing bolts but the tabs on the wings seem too thin for the blind nuts. What have you guys done there? Maybe add some light ply to the wing tabs?

Absolut Yak

My Feedback: (4)

Jaco

I broke the tabs on my wing hold downs several times. I ended up pinning the tabs to the leading edge balsa with bamboo rods (didn't have dowels), then 1/4" ply to match the root rib, plus polyurethane glue down inside the junction of the R-1 root rib and the leading edge and trailing edges. That fixed it. I use blind nuts and they work just fine.

Doug

Jaco

so just to clarify, did you make new tabs out of 1/4 and glued on the outside of the existing tabs or made a copy of the entire root rib and glue on the inside?

Thanks for your help.

Absolut Yak

My Feedback: (4)

I copied the entire root rib including the tabs and epoxied it over the existing root rib. John McNees or Dion may have the other OMP recommended fix for you and/or pics of that fix. It involves making another ply tab and inserting it on the outboard side of the existing tabs. I am sure that would be easy and beautiful and lighter, but I did what I knew would be solid, and QUICK.

I really shouldn't hijack OMP's chance to respond, but I can't help myself.

Doug

AFSalmon

My Feedback: (3)

Both methods of fixing broken wing tabs can be used. We generally add a 1/8" ply doubler on the outboard side of the tab and cut the wood out int eh leading of trailing edge so the ply patch tab can extend into the wing and secure to the original ply root over several inches. This way you don't have to add an entire root rib doubler and change the wingspan amount.

I'm surprised anyone has to move the battery rearward as most of the giant profiles typically come out tail heavy with OS 160s and right on with larger heavier engines. But if you read the instructions on the kit side of the manual it does describe how you can place the battery hatch anywhere along the fuse and servo wire tunnel to achieve proper balance. Be sure to set the whole plane up ready to fly and check your balance before cutting any holes! You may even want to test fly, add tail weight to find the sweet spot you like, land and mark the cg location you want. Then you can remove the temporary tail weight and move teh battery rearward until you get it right on. This technique will assure you cut your new hatch in just the right spot.

RNick

Salmon
Is the brocken wing tabs a problem with the kits to? I just finished covering my kit. Should I add the doubler to the tabs on my kit built Yak?
Randy

AFSalmon

My Feedback: (3)

Kits and ARFs are built the same and there is no problem unless you crash, or bang a wing on the ground.......SO DON"T DO THAT!

on-your-six

i felt he wing hold down tabs were way to thin and weak so i skinned
the inboard end with fiberglass cloth then i put a 3/8" sq. hardwood on
the out side to mount the blind nut

on-your-six

here are some photos of what i did to the wing tabs
and some motor install picks

LVS

My Feedback: (6)

what gasser are you using and how does it balance and fly? where are your battery packs?

m4x pow3r

Thanks for the pics. So are you happy with how it flies? Does it wing rock in harrier?

on-your-six

i am using a mvvs 2.15 gas motor i have not finished the plane
due to the fact that morris hobbies failed to order headers & tuned
pipes for this motor i have been waiting 6 weeks for these items
i asked here on rcu if any one new where i could find these items
and one kind guy suggested mvvs of canada and guess what they had
header and tuned pipe i should receive them on 4-2 or 4-4 then i can
finish the plane and get it cg,ed - so i have not flown the plane
i think it will fly good
tg