esc

Hi Guys,

Although I have built many R/C aircraft over the years this is my first experience with a Hyperion Yak55SP 3D profile, and I am wondering if you can suggest how to mount the Li-Po batteries to the airframe. The supplied velcro does not seem long enough to wrap the battey pack properly, and knowning about mass and inertia it scares me to think about the damage a loose battery could do. Can you offer me any advice as to correct mounting techniques.

Also, anybody that is familiar with this plane- I have added 2 degress of right thrust to counteract spiral prop wash. Do I need any down thrust? What control setups have you found that work well, and is the C of G correct in the instructions?

Thanks,

Dave

FlyingGreg

My Feedback: (4)

Dave--

I like to attach a length of velcro to the bottom of the battery and one in the plane running the length of the battery. Sometimes you must coat the bare balsa in the fuse with epoxy to provide good adhesion of the sticky back velcro. This way you can move the battery a bit forward and aft to achieve the CG that suits you. Another piece of velcro wrapping around the battery insures it will not move. I buy velcro in 10 ft lengths at home improvement stores and also in stores like Walmart. I'm sure you have similar stores in GB.

Sorry, I don't know anything about the Hyperion Yak and thrust angles. I am in process of assembling a Great Planes Reactor which has thrust angles built in. Surely someone out there in "hyper land" can answer your specific question.

Good luck,

Greg

esc

Thanks Greg, Your info. confirms what I thought had to be done. Not sure I like having to glue velcro to brand new battery packs though :-)

I have just been checking the balance of the Yak and it is VERY tail heavy, yet I have added nothing to the construction that would cause this. I even tried a set of TP 1320 mAh lipo's to try to bring the C of G to the 60mm recommend back from the leading edge. No dice. Not even close.

I am now think of changing the motor, a Hyperion Z-2209/32 (41.7grams) for a Hyperion Z-2213/24 (53grams), using 1800mAh cellls and possibly one of the new Waypoint 35A ESC's. Dead weight on a plance is not so good, but if I change the above at least I am getting a trade off in extra power and extra flight time.

Any thoughts anyone?

Regards,

Dave

Gary Hoorn

Dave,
Put the smooth side of the velcro on the Lipo and the Hook side on the plane. Run the velcro the full length of the Lipo. I normally install a slightly longer piece of the hook to allow for CG adjustments. When you install the Lipo just push it securely onto the hook side of the velcro. It will hold. I have hundreds of flight using this method and have never lost a Lipo.

Take out that right thrust or you will find the bird pulling right on takeoff, uplines, loops and while attempting to hover. Heavier motors and Lipos will degrade the performance. The bird flies great as designed.
Gary

esc

Hi Gary,

Thanks for your reply. The information about the right side thrust has come just in time as I will be test flying the beast as soon as the weather is suitable. I will remove it before then.

Last night, prior to reading your post, I attached self-adhesive velcro to the plane and batteries, pretty much as you describe. I still don't like this method of fixing, but as you & others have had no problems I will suspend my fears until I have flown the model.

I had already decided not to go down the bigger motor/heavier battery route after some experimentation with a heavier Li-po pack. Switching to 1320mAh only made 3-4mm of difference to the CofG. The bird weighs 14oz all up, and so I decided the bigger motor was not required.

With a set of 900mAh li-po's right under the motor the CofG is 28mm behind that suggested in the instructions. To alleviate possible problems with the test flight I have reduced the maximum throws and set the rate switches to give me a safety net.

Where is the CofG on your plane, and what throws are you using?

Regards,

Dave

pdubree

Hi Guys
Glad to see your posts. Your right this thing is extremly tail heavy. I wonder if the hperion folks are aware of this. I don,t like the way you have to put it together.
It was a pain making the servo holes large enough for eflite s75 servos. Finding the slots for the guides and the conrol horns were a pain. Over all I rate this arf lousy for
assembly. Ah the battery location. Heres my plane. Under the nose as far forward as possible i will cut a slot for the battery and put balsa triangle supports on each side for
the battery to rest on. Paint the basla parts black. For additional nose wieght add stick on lead weights. I biught 20z of weights hope this adds enough. If not Hperion will hear
from me. Has anyone flown this yak? How did the handle cg problem? Any thought please let me know. Thanks