Thursday, May 12, 2016

HobbyKing Aether 3.7 Review Part 2

HobbyKing Aether 3.7
Aether V2 2016


It is important to decide early how many pieces wing will be and plan accordingly. I decided I was going to build a 2-piece wing. 

I also decided to use a set of SBUS servos I had on hand. Using SBUS simplifies the cabling and negates the need of a fancy cable harness for the wing.
Warning: Be careful when installing the flaps and ailerons. It is very easy to end up with flaps and ailerons rubbing against each other or the ailerons rubbing against the tip sections. I would advice the builder to delay hinging the wing until the wing sections are glued together. 
After unboxing the plane I found it nice that the flaps had been redesigned so that they could now move down to 90º. Once I started putting together the wing I was surprised that we were instructed to use "clear tape" to hinge the flaps but no tape was provided. Moreover the instructions for using taped hinges were to generic and unclear. It is a good idea to see a couple of videos or how to properly use tape hinges.

I didn't want to order expensive glider hinge tape so I went to my local office supply store and bough a couple of rolls of "general purpose" clear tape. The kind that says is water resistant. Avoid the mate-writeable tape (rips more easily). I compared the clear tape I bought with heavy duty packing tape and they were very similar.

I removed the flaps from the wing careful and inspected the covering it was in good shape.

Inspecting the fit of the flap against the wing I found there was a noticeable gap. Look at the picture on the left near the top. Fortunately this gets sealed by the tape hinge.

Tape hinge can be tricky. Put the tape wrong and your surface will not move as much as you expect it to move.

A good tutorial can be found here: Hinge Tape tutorial

Warning: The link above does not describe installing tape hinges for flaps but ailerons. Take that into account when transferring the technique to the Aether.
I used a small amount of blue painters tape to make sure you have the movement that you want. Once you apply the clear tape to the covering it is very difficult to remove without ripping the covering off.

Make sure the covering is completed adhered to the the wood. Use your covering iron to make sure the film is firmly adhered to the wood.

Make sure the area where the clear tape be applied is very clean and free of grease. Use alcohol pads remembering not just to rub the same side on the same place. change sides and dispose of the pads often.

Properly installed tape hinge will allow the flap to go up just enough to implement reflex and down 90 degrees.

The instructions call to apply tape on one side only but I followed the technique described in the link above and had tape on both sides of the flap.

Servo Mockup

Using the center carbon fiber rod I joined the center sections and tested servo location and cable lengths. My flap servos easily reach the center of the wing.

This also exposed an annoying problem: Where are the cables supposed to come out into the fuselage? It is not clear. There are no precut holes for the cables to go from the wing  into the fuselage. Looking at the V1 thread I see that people cut a hole on the sheeting near the middle to run the cables into the fuselage.

Using the carbon fiber joiners (after a great deal of sanding) I joined the aileron sections to the flap sections.
There are two sets of carbon fiber joiners. One connects the flap sections to the aileron sections and the other ones the aileron sections to the tip sections. All four joiners required sanding to fit in the slot.

There are plenty of openings to route the aileron cable from the aileron bay to the center of the wing.

My SBUS Flap servos have a secondary plug that allows me to plug the aileron servo cable on the flap servo. This eliminate the need to elaborate wing cable harnesses.

The instructions call for epoxying small pieces of hardwood on the servo trays and screw the servos there.

Instead of doing that i chose to glue the servos in. To do that I wrap the servo in blue painters tape and then use a small amount of gorilla glue to glue the blue tape to the servo tray. If I ever have to remove the servo all you do is cut the blue tape.

Instead of blue tape some modelers use shrink tube.

 This setup allows me to have two cables going into the fuselage instead of four. There are no precut openings so we need to cut the sheeting near the center ribs to let the servo wires pass.

Joining the wing parts

I wasn't able to take many pictures of this assembly procedure. But it is straight forward but it can become time consuming and somewhat frustrating.

Here is what I did.
  1. Using the manual made sure I had the right parts to a list of all the parts to join the wing sections. This can be a little confusing. And in my case I ended up with left over carbon fiber rods.
  2. Sanded all the joiners. This was a frustrating job. the sanding was done to reduce the roughness on one side of the fiberglass joiners. only then they would slide in position.
  3. Had to sand some of the carbon fiber rods used in addition to be big CF joiner on the wing. otherwise they would not fit into the holes provided.
  4. After I had all the parts test fit I proceded to glue the flap sections to the aileron sections.
  5. Then came time to glue the tip sections to the aileron sections. This was particularly frustrating because the small carbon fiber tubes used in addition to the carbon fiber joiners were very easy to push into the wing bay.
  6. I used Gorilla Glue to join all these parts. Care must be taken because this glue expands and could push parts apart. The manual recommends to use Epoxy.

Wing aileron/flap hinges

Only after the wing sections have properly glued together (or snapped together if you have a 4-section wing) it is time to glue the aileron hinges permanently.
A lot of care must be taken here so that the ailerons do nor rub against the flaps or against the tip sections. Move the aileron left and right making adjustments until the aileron moves without touching any other parts through its range of motion. Take your time on this.

If you waited for this moment to hinge the flap we have to make sure it doesn't rub against the center of the wing.
The aileron and flap can rub each other at different points through their motion range. We must make sure that the aileron does not touch the flap through the range of motion

We must also make sure that the aileron does not rub against the tip section

Note: I rushed to CA the ailerons in place before the wing was assembled (my wing is 2 pieces). It seem easy to do it at that moment because I was dealing with one unattached wing section. But in the end the aileron was rubbing against the tip section. The problem was solved with some sanding.

Wing control linkages

Let me start by stating that the linkages provided with the kit wouldn't have been my first choice. There are many alternatives out there. However to be fair to HobbyKing I decided to use what they provided and after the test flights I find them adequate.

Flap linkage: Full down deflection. Note that the holes on the control horn are not aligned with the hinge line. This was done on purpose so that we could get a full close to 90º deflection.

 Flap linkage: full reflex position.

 Aileron: Full up.
Aileron Full down.

Go to Part 3
Back to Part 1

1 comment:

  1. HobbyKing Aether 3.7 is a nice plane toy. I did gifted it to my son when he got the position in grade 8th. I feel really good when i see him enjoying with his gadget.