Originally Posted by slo-fly

It's a weight thing. My hyperion 2950mah 4s weighs 12.5 ounces, the 2600mah 3s weighs 8 ounces. That and 3s lipo are cheaper.

Check out this battery. Aside from being more expensive, it's a 4s 2700mah and weighs 8.4oz

http://www.amainhobbies.com/product_...C-148V-2700mAh

... still suck big-time.

I thought that after over a year E-flite would have addressed the issue of props so bad they can't be balanced, so I bought one.

I put it on a DuBro TruSpin balancer and positioned it vertically; it immediately swung level as shown. I started by putting thin layers of CA on the light side of the hub, and eventually had a big thick blob. Then I put 5 or 6 layers of Scotch transparent tape on top of the CA. Then I tried Flex-i-filing the heavy side. Then I switched to a Dremel. When I had removed a lot of the heavy-side hub I started removing material from the blade roots.

After over an hour of this I decided that even if I could get this prop to balance I wouldn't put it on the Yak and go flying.

Fortunately I had rat-holed a couple of APC 12x6Es, so I spent about 10 minutes total balancing both of them, and I'll put one on the Yak.

The ESC of the Yak came attached to the fuselage with a material that looks like Velcro, but isn't. The best description I have is two identical mating surfaces that are both similar to the hooks of hook-and-loop fasteners.

It is the same type of material as that supplied with AnyLink modules to attach them to transmitters.

What is this stuff, and where can I find it? Horizon Tech Support wasn't any help.

Originally Posted by kevinrc

The ESC of the Yak came attached to the fuselage with a material that looks like Velcro, but isn't. The best description I have is two identical mating surfaces that are both similar to the hooks of hook-and-loop fasteners.

It is the same type of material as that supplied with AnyLink modules to attach them to transmitters.

What is this stuff, and where can I find it? Horizon Tech Support wasn't any help.

I have being serching for a wile for the same as you wirh no luck. I do like it a lot for my other airplanes if you found something let me know please.

I am using right now the align and turnigys hook and loop stripes not the same but very clean thin material not a fluffy loop like normal stuff the bad side is they are strip and need to glue with ca. Also parkzone have some sticky hook n loop similar that the one on the micros they work just great y have only found them on ebay.

Originally Posted by slo-fly

It will probably fly but feel underpowered. You may want to try a 14x7 to bring the watts up. I use the 10 watts to every ounce method, you would be good for a 46 ounce yak. I would shoot for 600 watts, I probably wouldn't attempt flying at 440 watts but it's probably possible. Your lipo is too small, I bought a hyperion 2600mah, 45c, 3s, not sure if that's gonna be big enough.

I was able to fly the plane with a 14 x 7 prop, and a 3s 3200 battery. However, the 14 x7 struck pavement on both takeoff and landing (prop broken). I like the 14 x 7, but it just does not have the clearance.

Originally Posted by DaxFX

Also parkzone have some sticky hook n loop similar that the one on the micros they work just great y have only found them on ebay.

Velcro for Posters is to me indistinguishable from the stuff Parkzone micro batteries are attached with. It's available at Lowe's or Home Depot (can't remember which).

Originally Posted by ufale

I was able to fly the plane with a 14 x 7 prop, and a 3s 3200 battery. However, the 14 x7 struck pavement on both takeoff and landing (prop broken). I like the 14 x 7, but it just does not have the clearance.

Did you get any watt numbers from the 14X7? I was afraid clearance might be a problem with a 14" prop, maybe have to bend the landing gear and or get bigger wheels. Option 3 (this one costs a bit more) get the hyperion 3025-8 motor and 45c lipo, then you'll have enough power for a 12" or 13" prop on 3s. I will get an AUW on mine, it should be fine on a 12x6 prop with 3s. It would be nice to have the capability to run 4s for speed runs and 3s for 3d flying without changing a prop.

Originally Posted by slo-fly

Did you get any watt numbers from the 14X7? I was afraid clearance might be a problem with a 14" prop, maybe have to bend the landing gear and or get bigger wheels. Option 3 (this one costs a bit more) get the hyperion 3025-8 motor and 45c lipo, then you'll have enough power for a 12" or 13" prop on 3s. I will get an AUW on mine, it should be fine on a 12x6 prop with 3s. It would be nice to have the capability to run 4s for speed runs and 3s for 3d flying without changing a prop.

Sorry, but I did not get the numbers for the 14x7. I would do it now, but I do not have another prop. I might just take your suggestion about the 3025 Hyperion.

My all up weight with the 3s is 61 ounces. I need to ditch the telemetry system soon (it bothers me more than it helps), get a smaller rx and change the ice lite 75amp esc to a hobbywing 80amp esc. This should shed another 2 ounces or so and put me at 59 ounces, 576 watts would be perfect for 58-59 ounce 3d plane, slap a 4s in there for an 1100 watt high speed 3d aerobatic racer!

On my next yak build I will shoot for around 56 ounces by using hs82 servos instead of hs5085, hobbywing 60 amp esc, hyperion 3020-8 motor and 3s lipo. I'm not sure if a 12" prop will be enough on 3s with this combo though, a 13" is probably better for this motor but a 12" might work due to higher Kv rating, I think it's 1135Kv so there should be about 1900 rpm increase on 3s compared to the 3025-8 motor on 3s. It should be around 13,500 rpm with the 3020-8 on 3s, the 3025-8 on 3s is around 11,600 rpm, stock motor on 4s is around 15,500 rpm.

Have any of you guys tried to modify the CG to make it tail heavy for 3D?

My first motor was a Hobbypartz Rocket 3025 1130kv and it was a rocket. It pulled over 700 watts with a 12x6. Wish I hadn't burnt it up testing.

Got a few more flights in this afternoon with a 13x8 this time around. Much better power than the 12x6 but it's really hard on the motor in 100 degree heat. I had to swap planes every battery to keep motor temps in check. I think 13x6.5 will be perfect when I can get some more.

Tape a washer or something else to the tail of the plane if you want to experiment with CG. Mine's already light up front with a 3s battery. I'll measure my CG later for grins.

I think the best way to move the CG is to move the battery or esc instead of adding weight to the tail. Otherwise you're just adding dead weight. If you can't move the battery back far enough, you can always cut out a little bit of foam at the back of the battery "tray".

Do this Yak have bad charasteristic if tail heavy? I like my other 3d's a bit more tail heavy but i dont know why i am afraid to try the yak more tail hevy.

Maybe the brick feeling does not allow me to try

It seems like there is a wide envelope for CofG, be careful to not push it too far back, it's more prone to stalling and when it does it drops like a brick. It can be a problem on slow landings, especially throttle off landings. I've noticed the wings dont rock before it stalls, it just falls on it's face, usually breaking the fuse.