Magic Hand 73" yak build thread
 

I just got a new magic hand yak and am very impressed with it. Below are some preliminary pictures along side a Extreme flight Yak 74". The magic hand has a very nice cowl with blind in fuse attach points. It is pre plumed with a fuel dot and also had aluminum anti rotation pins in the wings. The wings appear to be prehinged and glued (CA hinges all around). The horizontal stab is one piece. The canopy is top notch. Hardware is average. There were no instructions with mine and the wing tube is a porker but other than that the wood all appears good. You will see the airfoil is thinner than the EF yak on both the wings and the tail/rudder. I like the cowl MUCH better on the Magic Hand. It is stiffer and has a cowl ring for the blind mounts plus there is much more detail.
I will post some weights tomorrow.
Pricing for this quality is unreal, if it flies like it looks it will be a winner.

The set up will be as follows:
OS 1.60 with Slimline Pitts
4 5925 Hitecs on Ails and Eles
1 5985 on the rudder
1 225mg throttle
NOBS battery 6vt nicad either A or sub C (yet to decide)
I will probably change out some hardware as I go with dubro stuff.

target weight is 10-10.5 lbs

Enjoy the pics

RE: Magic Hand 73" yak build thread
 

Here are some more. the EF Yak is there for prospective of a known bird only. I will not be compairing the build to their product.

RE: Magic Hand 73" yak build thread
 

And a few more

RE: Magic Hand 73" yak build thread
 

kewl[8D]

RE: Magic Hand 73" yak build thread
 

I really like the looks of this plane.....

RE: Magic Hand 73" yak build thread
 

Will the wing tube from the EF fit this? To bad it didnt come with CF....

RE: Magic Hand 73" yak build thread
 

I don't know if the tube will fit. I will check it out. TBM will probably have somthing for it. The cowl and canopy some of the best I have seen.
Jeff

RE: Magic Hand 73" yak build thread
 

Here are the details on the kit and some weights.
below is a link to the kit at TBM. Sale price is $229.00 and $39.00 shipping.
http://www.troybuiltmodels.com/MHYAK.htm

I have a few pictures of the plane and the weights for the set up I will be using. The website shows this plane coming in at 10 lbs. I was hoping for 10-10.5 lbs but that may be a tad optimistic.

The plane comes double boxed in a very rigid outer box. The build quality appears exceptional. The surfaces are all double beveled, cowl has a ring for a hidden mount from inside the fuse. The glass and paint on the cowl are flawless and have great detail. It rivals any glass work I have seen on a model plane. It comes protected with tissue paper and bubble wrap. The plane comes pre-plumbed and the connections zip-tied along with a fuel dot. (smaller than needed and will be changed in future offerings per TBM, it will be changed along with the fuel line as it looks narrow). The canopy is very nice and again came double wrapped in tissue paper and bubble wrap. All covering was excellent quality. Hinges are CA type and are preinstalled in the wings. Tail surfaces are installed in the flying surfaces. The horizontal stab is one piece. My plane didn't come with instructions but they can be downloaded from the TBM site. The hardware included is average quality. I have an EF Yak NIB and the hardware is much better with the EF yak. I will probably be changing out some of the hardware for 4-40 dubro stuff.

The setup will be as follows:
OS 1.60 with Slimline Pitts muffler
Hitec 5925s on Ailerons and Elevator
Hitec 5985 on rudder
Hitec 225mg on throttle
6 vt Nicad battery

Here are the weights I have for the plane and the setup: I used a digital postal scale for the below weights.

Right Wing 15.7 oz
Left Wing 15.7 oz
Hor Stab 6.5 oz
Rudder 3.5 oz
Fuse 39.0 oz
Cowl 7.1 oz
Gear 6.2 oz
Wing tube 9.0 oz
Hardware 8.6 oz

Engine 38.0 oz
Muffler 5.8 oz
Prop (APC) 4.8 oz
Spinner 2.1 oz

Servos 12.0 oz
MPI arms 1.0 oz
Extentions 3.0 oz (est.)
Battery 8.0 oz (est.)
Receiver 1.0 oz
Switch 2.0 oz
Misc 4.0 oz (est.) Spats 1.6 oz (optional)
_________________

193 oz total all up weight
12.06 lbs
Wing Loading 27.59 oz/sq'

Magic Hand RC site data:

Length:1690mm (66.5in)
Wingspan:1850mm (73 in)
Wing area:65dm2 (1007 sq in)
Engine: 4C 120~160
Gas Engine 26-30cc
Weight:4.2-4.5kg (9.1-10lb)
Radio:4ch-6ch

(There is a slight discrepancy with TBM site on wing area 977 sq inches)



I will be starting the build in the next few days.
Here are a few pics of the plane as I was weighing it

Jeff

RE: Magic Hand 73" yak build thread
 

Here are a few more pics I took as I was weighing the plane.

RE: Magic Hand 73" yak build thread
 

And a few more.

Enjoy!!

Jeff

RE: Magic Hand 73" yak build thread
 

that is sweet to the bone[8D]

RE: Magic Hand 73" yak build thread
 

Ya it looks really nice... I can't wait to dive into the build. I don't know where they come up with the all up weights for these planes... Either my scale is off or things are a hell of a lot lighter in China.. LOL

RE: Magic Hand 73" yak build thread
 

It could be the weight less the engine. That would be close to their weight.

RE: Magic Hand 73" yak build thread
 

Wings:
I looked at the hardware again today and changed it out to dubro ball links and connectors as well as 4-40 threaded rod for the push rods. The included rods were 2-56 and had metal connectors and 90 degree keepers which I don't use on anything bigger than 40 size planes.
Here is a picture of the hardware, the four bolts are wing attachement bolts.

RE: Magic Hand 73" yak build thread
 

I then did the normal mounting of the servo and arm. The instructions are spartan at best although anyone who has ever built a plane or assembled an ARF shouldn't have any issues. I am using MPI 1 1/4" arms for this plane.


As I stated earlier there are no instructions on placement of the control horns so I winged it !! [8D] I Ran a straight edge down the side of the servo (which is 90 degrees to the hinge line) and transferred a mark on the aileron. I then moved the servo arm to the end of its travel and measured the distance from the hole on the arm to the side of the servo, once I had this distance (18mm approx) I transferred it to the aileron. The only remaining thing was finding out how far into the aileron to drill the hole and this was easily found by putting the control horn over the hinge line so that the hole in the arm is directly over the hinge line and marking the point where the control arm should go through the aileron. I made my mark and drilled though the hardwood bock. Once through I always put some thin CA in the hole to harden it more and then mounted the control rod.
What this does is give you great mechanical advantage when your surface is fully deflected. The pushrod is 90 degrees to the flying surface.

I also like to do a little sumtin-sumtin extra with the linkages. I lower the push rod linkage so that it is exactly the same height as the servo arm when the surface is fully deflected. The way the control rod is exactly parallel with the servo arm. Once again providing every little bit of mechanical advantage from the servo.

The finished product: Now do the other wing :D

RE: Magic Hand 73" yak build thread
 

My EF Yak came to 11 pounds 14 ounces with my EVO 45cc but I did alot of mods too...

RE: Magic Hand 73" yak build thread
 

Mike,
That is my next project. I have the EF yak in waiting. :)

RE: Magic Hand 73" yak build thread
 

Horizontal stab:
I installed the horizontal stab this morning. I have attached some pictures of how it went.
First I cut the covering from the stab opening and also the elevator servo bays. I then dry fit the stab and measured equi-distance out from the fuse at the rear of the stab. I also mark the center line of the fuse at the front and drive a T-pin in with a string attached and measure the distance from there to the stab tip to make sure they are equal. I then traced the outer edge of the fuse opening and pulled the stab out. Using an older soldering gun in trimmed off the utracote leaving 1/8" on the inside. I refit the stab and checked the angles I then leveled the fuse both laterally and longitudinally. Once I had a level on the canopy opening I checked the incidence of the stab. Once satisfied I mixed up some 20 minute epoxy and glued it in place, rechecking all the angles.
The only issue I had is the incidence changed once the epoxy dried from 0 to -1 approx. I was a little bummed because I wanted 0 across the board and there is really no way to tear it all apart to change it. So I will make the best of it. (I am only assuming 0 is correct as there are no incidences in the manual) Note: the stab opening is big and there is some space that will need to be filled. Once I had the stab in place I put a small amount of thin CA in the front to hold it in place.
Jeff

RE: Magic Hand 73" yak build thread
 

I'm also looking at purchasing this plane so I'm following your build with considerable interest. I would like to ask about your choice of servos. I noticed that you chose a lower torque, faster response, for the rudder. Why? I guess I would like to know your thinking on each.

Thanks.

Lyotchik

RE: Magic Hand 73" yak build thread
 

lyotchik,
I am putting a 5985 coreless digital on the rudder. This servo provides upwards of 170 oz. of torque at 6 vt. the other flying surfaces are 5925s which are at over 120 oz of torque. These should be sufficient for this size plane and a 225mg for the throttle. If you have any questions about the plane or the build feel free to pm me.
I have been looking for a battery for this plane and am going to go with a 1100 ma A123 pack at under 4oz it should give at least 3 good flights before recharging which will take less than 15 minutes on a cellpro charger.
Jeff

RE: Magic Hand 73" yak build thread
 

Maineflyer, I'm glad you are doing this thread. I am considering this plane for my Saito 1.80 that currently resides in the H-9 Edge that I am about to destroy. Keep the pics coming!! Thanks again.

RE: Magic Hand 73" yak build thread
 

plowboy1966
Thanks for the encouragement. The plane is well built although you will need to change out the usual hardware. The 1.80 should haul it around nicely.
Jeff

RE: Magic Hand 73" yak build thread
 

Rudder and Control Horns:
I finished up the tail group tonight by putting on the horns and the Rudder. This is pretty straight forward but there are no real directions with the plane so it is (shoot from the hip)... Sorta. I put a servo in the bay for the elevator and lined it up with the surface to get a point where the linkage wouldn't bind. It worked out to be about 1/2" from the inner edge of the flying surface. I then set the horns for the elevators so that the connection is directly over the hinge line. Due to the short length of the horn part of the washer was in the hinge line and restricted travel so I used the trusty Dremel tool to trim them. I am now getting 55+ degrees of travel both ways. :) I then trimmed the post to a reasonable length for the elevators and they were done other than sealing the hinge lines...
I then turned my attention to the rudder. I opened up the pull/pull exit holes in the fuse and stuck some carbon fiber rods in to see where they would intersect the rudder (note the 67" instructions say 135mm). I felt the rudder and this measurement is at the lowest end of the mounting block on mine ... thus the carbon fiber rods. I also ran a straight edge from the rudder servo bay to double check my measurement. It ended up being in the 155-160mm ballpark. I mounted the horn in the usual fashion. (always hardening the post holes with thin CA). Once the horns and posts were on I fit the rudder and walked the CA to the hinges. (I really wish this plane came with hinge points). This rudder is huge and I would feel much better with points. I then sealed the hinge line with some clear Monocote and the rudder tis done!!
Enjoy the pics!
Jeff

RE: Magic Hand 73" yak build thread
 

maineflyer,
Thanks for the detailed info and great pictures! Looking forward to watching the whole process and hopefully a maiden video. I'd just like to think that maybe some of these lower priced planes have to be good!! If this one is then other companies will have to meet the price and offer better hardware to be competitive. That is just good news for modelers everywhere. Keep up the good work.

RE: Magic Hand 73" yak build thread
 

If you go to Magic Hands website and Troy built models site you can see some of the videos. The videos of the plane look good.

http://www.magichand-rc.com/download.php?bid=2

http://troybuiltmodels.com/newsite/a...yak54_arf.html