SkyEye by E-do Model. Build log and review in progress.
Few months ago Henry from E-do Model announced their new airplane which they called SkyEye.
The name suggests from the start that this is a plane intended for FPV, and is the very common on planes which are designed for this purpose.
I liked the fact that the announcement went together with close-up pictures and videos of the plane, not only the 3D model, that way we can see better what this plane is up to – and to be honest, it got my immediate attention because I saw few features that looked very interesting. I will talk later about each one.
So, I have contacted Henry to arrange for me a sample for review.
He agreed to provide me a prototype and here the journey begins…
As always, EMS refuses to ship in my country so I had to find a workaround. The plane was sent to my family in another EU country and from there it was sent to me by bus – 2000km.
The plane arrived without a dent or scratch. It was only covered with one layer of bubble wrap and there were a lot of free space in the box. That let me think that the EPO foam out of which the plane is made, is strong enough and does not deform easily. But packing should be improved by just a little bit.
Happy to see it, I have started to build it right away, well – almost right away, because I was busy with another project that I had to finish I was according only few minutes/day, for which I have to sincerely apologize to E-do model guys and especially to Henry.
The unboxing video I have made in advance, and I have uploaded few days ago for you.
In the next posts I'll try to explain the building process I went thru.
P.S. will try to add all the videos on this first post for easy finding.
Buildlog - the fuselage
In the box there were absolutely everything needed to assemble the plane except a manual.
I’ve put the parts together and saw that the building process is easy except the tail. I had few parts/carbon rods which I wasn’t sure where I have to install them, therefore I have spent some time figuring out how to assemble the tail – but when I found the correct way - I can tell that it is quite easy. Meanwhile, Henry has sent me some photos of how to assemble the tail – which I may suppose that they will be included in the manual.
I will not follow the exact sequence I have followed to assemble the plane, but the one that looks correct process wise. So let’s start with the fuselage.
The fuselage comes in two halves which have to be glued together. After gluing it together it will form a fuselage with two bays/decks – upper and lower. I am still impressed by how much room is available inside – and this is the first nice feature of this beautiful plane. As you can see, only in one half, into the lower bay, you can put two rows of 4x 3s3000mah batteries (8 in total - I haven't so many batteries to show).
Beside that – the access inside the fuselage also, is quite generous. From the top one can access the upper bay by removing two hatches and the lower bay via generous doors on both sides.
Before gluing the parts together it is better to do some work inside. Everything can be done afterwards, but doing it before makes the life easier.
Gluing the plywood which acts as support for carbon rods on which the wing is installed, from inside the fuselage. In this step I used the CA glue to speed up the building time. Steps like this are the easiest, because every part that has to be glued has pre-molded channels for easier alignment. If one can miss-install such a part, then going back in the ‘90s to learn the basics of aeromodeling is needed.
The next step is to cut out the doors for access into the lower bay, glue in place the door stoppers from inside and the piece of plywood in which the latch will lock. This step can be left for later but is just easier to do it now when the fuselage is apart. Also cutting the reinforcement of the door hinges later would be quite complicated; however the foam which is left out to form the hinges for the door is quite thin and soft and requires reinforcement. I came to the point when the hinge has broken and I had to glue normal hinges in place. CA used as in previous step.
After this step I continued with the most important step which must be done with care – gluing the parts together and trying to perfectly align them. Sounds easy… but is not – I use the Polyurethane glue (I think oversea it is called Gorilla Glue) for this kind of work, because it expands and fill the gaps where may be the case.
In this step I have figured out that I have to install a short carbon rod which is used to reinforce the aft of the fuselage.
The glue should be spread carefully and the excess should be removed, especially around channels where something has to be installed (e.g. tail boom).
Stacking the halves together and trying to align them as perfectly as possible using some paper tape for fixing. I choose paper tape because it sticks well on the EPO and afterwards removes easily.
The parts that one has to pay attention are the rear channel where the tail boom should be installed and of course the nose of the plane too – this will represent the owner.
Since the Polyurethane expands, I am using weights to apply some force (otherwise the force of expanding glue will dis-align the parts) and let it dry like that over the night.
In the picture above you can also notice the support and aligner(mainly a wing rib) of the wing carbon rods which have to be glued outside the fuselage. I have glued them before, but this step can wait until now. Gluing them after the fuselage is glued together, makes alignment with the carbon rods more easily. I have used for them CA but Gorilla Glue is preferable.
While the fuselage is left alone to dry, some other parts can be glued together. One of them is the forward hatch, which also can be used as a pedestal for camera, gimbal or what you can think of.
I have used CA just to speed up the process, but would use polyurethane if I had the time.
Also the supplied latch is glued in place with CA glue (On the second hatch cover the latch is glued in place identically and is the only step to be performed there).
E-do model designers are really concerned about aerodynamics, therefore in the kit they supply a nice addition - a canopy for this cover, in case one doesn’t want to mount anything on it.
The canopy has to be cut out and glued in place if one wants to use it.
The next day, after the glue cured I had to remove the excess in some places, especially from the channel where the tail boom is installed.
But also from inside the fuselage, otherwise the plywood pieces that should be installed inside to reinforce the decks would not sit perfectly.
Then I have glued into the fuselage the tail boom holder.
Guys from E-do Model provided the holder made out of aluminum. I am not sure why, because it is cheaper or because it is better
It is definitely nicely machined – I would pay a fortune to find someone around here to make a part like this, but unfortunately in our hobby every gram is counted and this part is weighting as much as 52 grams. I think this is overrated, especially for a part which is installed behind the CG.
So I took the opportunity to use the 3D printer which was keeping me busy (remember I’ve told about the second project?), which was not finished yet at that moment but able to print already.
After drawing the holder using the original measurements, I’ve printed the holder using PLA plastic.
I’ve printed the part mirrored without intention. This was my absolutely first 3D printed part so I had to learn yet to setup my printer and slicer correctly, but it was also a good calibration test part - my printer is perfectly calibrated
Guess what – it works as good as the original one, but is weighting 5x times less – at only 13 grams. So, in case I need some more tail weight I’ll better glue a 10g piece of lead in the tail and still I am saving 30g.
I’ve glued the holder into the fuselage with the CA. It works better in tight spaces, cures faster, and looks clean.
Next step was to glue the plywood ring in the nose, on which the dome will be fixed with self-tightening screws. Also here, the little misalignment between two halves of the fuselage is covered. Smart move
Not finished yet with the fuselage? No – few more steps.
We have to glue the plywood parts for the decks, and the support of the tail boom from inside.
Tail boom support fits nice and snug therefore I’ve used CA.
For the decks in the upper and lower bays I’ve used polyurethane, and again – few hours of resting with some weight applied.
Once again you can see how much space there is inside the fuselage. In the upper bay I was able to fit a 50Amps server power supply
This is how it looks afterwards.
As you can notice in the picture above, there are two channels. One can fit another piece of plywood which will split half of the upper bay in two layers. Very smart design if one wants to install a lot of electronics. This will make the installation easier and cleaner – which is another nice feature of Sky eye.
It is not necessary to glue it in place – it slides in and out or can be totally removed. There is a lot of room for that.
Gluing the small pieces of plywood for the hatches locking system and we’re almost there with the fuselage.
Single Pusher or Twin tractor? This is the question!
Well, this is the next interesting feature of this plane – you can choose to configure your plane as you wish – Single pusher version or Twin tractor version – in the later configuration, the motors will be installed in nacelles on the wings. If one is too crazy, a three-engine configuration is possible . Did you think about DC-10 or MD-11? I did for sure
For the twin motor configuration the disadvantage is that the nacelles have to be glued on the wings, so it does not give the possibility to go back to a single motor version.
This step requires less effort in building process that time to decided between which configuration to choose.
Take the supplied plywood motor mounts(two are for nacelles and one for the rear mounted motor)...
Glue them with polyurethane glue.
After this last step, we're done with the fuselage, uhhh… I hope so… anyway.. let’s start building the most interesting part...
The wing is the most interesting part of the Sky Eye, because of its profile.
E-do model came with a profile which I have not seen before on FPV airplanes. It looks very promising from the aerodynamic point of view.
The wing has a very nice camber line – and if you don’t know what this means – I would like to directly quote the Wikipedia:
The camber works as you would have the flaps down – that’s why the stall speed is lower and the lift is increased. But it has also a down side – the cruise speed is also lower – therefore if the plane is intended for long range flying – it would take a little longer to travel the same distance compared to a plane with flat profile, e.g. Skywalker or X-Uav Talon. That’s why long range on this plane can be really boring
Personally I like to soar in the thermals more than doing long range stuff, so I am confident that this summer I would beat my record – climbing above 1.8km without motor. I can’t wait… but before that, I have to finish building the plane
On the wing, there is no much to do. First of all, as you probably noticed already, I have glued the end ribs on the both halves of the wing.
I’ve also glued in two reinforcing carbon spars, the servo, and installed the horns and pushing rods.
The wings has pre molded flaps, but I didn’t cut them … I really don’t think they are needed but we’ll see later.
Since I’ve already saw that the foam hinges are quite soft, I decided to reinforce the aileron hinges from the start. I’ve used for that reinforced duct tape.
And since the guys at E-do model are concerned about aerodynamics of the plane, I should be too – that’s why I’ve covered the channels of the servo cables and the channel for the flap servos with paper tape.
The last bit on the wing was to glue the short carbon spar that is used to lock the wing into the fuselage.
I personally don’t like this method of locking the wing – I don’t like when the assembly of the plane in the field requires tools. Really, there isn’t much lateral force in the wings to require such a tight locking. A small rubber ring and two hooks – one on the fuselage and one on the wing, would work better for me .
I will definitely redesign the locking of the wing.
Actually, that’s all what have to be done on the wing, except if you want to setup your plane in Twin motor configuration – then you have to assemble the nacelles and glue them to the wings.
Of course, I haven’t glued them in place, they are just for representation. As I’ve told in my unboxing video – at the moment, I don’t have all the electronics needed for twin motor setup. But I may modify it later... so please stay tuned
I like everything about this wing. I would take it with me in bed, considering how sexy it is. All the molded details make it looking very “scale”.
One particular thing what I like is the mark – CG with BIG letters. No more rulers, no more markers – just be sure you’re CG is spot on.
Ok, the story about the wing could never end – let’s move to the tail .
Well, the tail was the first part that I have assembled after receiving the plane. As I said – there were no manual in the box, but it also has one interesting feature which makes it a little bit – different.
The plane has a feature called vertical landing. That means the horizontal stabilizer has the ability to deflect upwards. I am still not confident that this would work. From videos on the internet, I would say it is a fast controlled crash rather than landing .
Thanks to designers – they made it possible to lock it in place with two bolts.
After understanding where all the pieces have to be installed/glued the assembling is straight forward....
First of all, I have glued the fiberglass reinforcement on the horizontal stabilizer.
Then I have glued the corresponding fiberglass reinforcement on the fixed part of the tail. This part also acts like a stopper, so that the stabilizer does not move down – only up.
A carbon rod will be inserted thru the moving part (horizontal stabilizer) and the fixed part. It will make the axis/shaft for the stabilized to move on.
Also if one wants to disassemble the tail for easier transportation – the spar could be removed by pushing it out with a screwdriver, or anything round of that size.
The channel bellow the rudder will accommodate a 12g servo for the stabilizer. My personal opinion is that something less than 50g here will not work. The surface of the horizontal stab is too big for a 12g servo.
The channel on the stabilizer will accommodate a 9g servo for the elevator.
The servo for the rudder has a special place on the vertical stabilizer. Here I think, they misplaced by a few millimeters, either the servo or the horn.
The full assembled tail has to be glued on the tail boom. This is what I dislike. If they made such strong aluminum tail boom holder, they could something similar on the tail side too.
The horizontal stab can move as much as this, so that it doesn’t intersect with the rudder.
Or it can be locked with two bolts, as I said earlier.
On the tail I have used only CA, even to glue it to the tail boom.
The servo cables are going into the fuselage thru the tail boom. Two servo extenders of at least 50cm are needed.
Inserting the tail boom into the fuselage, tightening the bolt on the tail boom holder and that’s all about the tail, and about building process.
Now I only have to install the electronics and we are ready for the maiden.
Joined May 2010
a twin motor setup will definitely be more efficient and easier to launch(if hand launched) - but I don't have all the electronics necessary to setup it as twin (mainly two identical motors and esc's).
about "better" - can't say ... that's all up to the airframe.
Yes, if one is crazy enough, a twin-tractor-single-pusher setup can be easily achieved. It may be that one day I'll lose my mind..
The successful maiden
well, as you might know, the weather in Europe this summer is not so generous to us(even now is still raining), therefore I had to delay the maiden a few weeks, then I was not able to bring the team together due to the unavailable free time for all.
But I couldn't postpone it forever, and I decided to do it by my self - (therefore the video quality is suffering, sorry for that ).
I've only had two flights on that day, that's why I do believe it is too early to have the final conclusion, but I would like to already share some remarks:
The only cons I have identified so far, is that with all the weigh in the front, GoPro, RunCam, 2x3000mah 3s batteries, Video Tx, the AP and DragonLink Rx on the CG and additional saving the weight from the tailboom holder - the plane was in balance - or keen to have aft CG.
Most probably a gimbal in front or twin motor setup will be slightly different.
I invite you to watch the video.
You can turn your favorite music on if you don't like to listen to my annoying voice.
I will definitely do some adjustments and will have some more flights, afterwards I will come with follow-up videos. So, please stay tuned...
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