torsdag den 5. juni 2014

Hobbyking H4 Quadcopter frame

Hobbyking H4 Copter Multi-Rotor Quadcopter Frame 470mm

You can also check this article Hobbyking H4 Quadcopter frame remodelled
You can also check this article Hobbyking H4 Tuning for better flight and video

Well after a number of crashes the carbon frame on the Hobbyking X650F Glass Fiber Quadcopter Frame, could only take so much of a beating, bits and pieces are now falling off, even after minor crashes. So i decided to purchase a new frame.

The Hobbyking H4 Multi-Rotor Quadcopter Frame is relatively fair priced, $29 + shipping, i was to choose between a cheap ebay multirotor quad frame or the H4, the choice fell on the H4 as i has tubes to get rid of the wiring.

The package comes neatly packed, with the bits and pieces bagged in sealed plastic bags. There is no boxed manual but it can be downloaded off the Hobbyking website and the H4 is pretty simple to construct.

 Note if you going to hide your wiring, construct the frame leaving either the top or the bottom frame  unmounted until your wiring is done and tested, it takes quite a while to get all the nuts undone if things go wrong.
Other things to be aware of on this frame, the flight controller mounting holes on the top plate, are partially covered under the parallel green tubes, this is a slight drawback, screws can be mounted by lifting the tube, but when tightening the whole frame, you will notice a slight uneven crest on the carbon plate, after mounting the whole frame and tightening the screws. So live with it or re-engineer it.
 
You have to find/buy a special small tool to mount the nut through the motor mount hole, I simply reversed the nut and bolt, so the bolt goes through the bottom, put the bolt and balanced it on an Allan key and then fed it gently through. The nut was tightened from the top, not very neat, but it did work.
The Landing gear is the biggest con on this unit, during flight even smaller rough landings, causes the landing gear to bend or flatten. They can be put back in place relatively easy, but at the cost of wearing the metal out. This is where I see my first breakdown, unless i engineer some way of strengthening it.

 The tubing is pretty tight, so feeding cables through them takes some patience and some relatively stiff wire.
I could not align the holes to mount the motor the way i wanted so i could run the cabling from the as in the picture. I can only fit 3 of the 4 screws, making it vunerable when crashing. I might have to r-drill the last hole.According to some users the motor mounts are susceptible to breaking when hitting the ground, even at low speeds.
Things got messy with all the wiring, but all the more fun to build

Power distribution mounted
Flight controller - With the cabling in place, I had to remove the upper middle plate, the cabling is too high, because of having the power distribution board
Notice the red and black cable to the Power disribution. They are over the edge of the frame, doe not look good, will have to think of how to take care of that.

As a novice, one of the great things about this frame is once the quad is airborne, its stability outclasses the X650F, keeping the quad in the air was much simpler and leveling was achieved almost from the first flight. Due to the reduced weight of the frame compared to the X650F, this frame archieved longer flight times, so to break it down, cool frame, stabil, good for longer flight time, but very easily damaged compared to the X650F, Much of the energy in crashes on the X650 is absorbed in the flexible landing gear, and also the tubes connecting the motor arms to the frame will also give as the outside bolt is designed so that the arm will give, when an arm hits an object, causing it to absorb the energy from a crash. The X650F can take a bit of a beating, before something breaks. The H4 does not have this play, an unfortunate crash on the motor tube will break it.
Be aware that Hobbyking does not seem to stock spare parts for the H4 frame as of yet, a look at the International warehouses website, shows that spare parts for this frame are not available so if something breaks, well either a new frame or get busy engineering.
Took the quad for a flight, while banking at a relatively slow speed, the one motor seem to cut out, dropping the quad from a height of 3-4 meters. It broke the motor mount, so have to re-engineer the prop mount.

Also broke the aluminium tubing, so as mentioned previously this frame is easily damaged/broken

Bent tube.
I decided to strengthen the frame by mounting the old motor mount tubes, this helped in making the quad withstand a bit more. The X650 which i used earlier has stronger tubes and thicker motr mounts. The tubes here are angled because my drill was out of action so just mounted them angled until i found a drill to mount the tubes at a right angle.

 I removed the original landing gear and mounted the landing gear from the X650F, i did it by simply drilling 8 x 3mm holes in the bottom plate for the landing skid mounts, making sure that the holes did not collide with the exsisting holes for tightening the bottom plate. There is a small bulge in the bottom plate, where the screws are tightened. That i can live with.


The mountd Landing gear seen from the bottom



The landing gear has given me enough clearance to mount my gimbal.

The Gimbal was mounted with three screws on to the bottom plate, making sure that i kept the holes for the motor mounts free.

If you are looking for reinforced motor mounts  for the original motor mount arms, you can order these aluminium mounts from Hobbycncoff ebay. The direct link follows below the picture.

http://www.ebay.com/itm/H-Copter-H4-QuadCopter-Multicopter-Aluminum-Motor-Mount-HobbyKing-4-/301643548846?pt=LH_DefaultDomain_3&hash=item463b5b48ae