Hobby King EPP FPV 1.8M Build Log
As you all know my primary fixed wing aircraft for FPV has been the Bixler, and while it’s been great – I’ve been looking for something to go a little further with in terms of flight time and payload. What I decided to build was a Hobby King EPP FPV to meet these needs.
It arrived and this is part one of my build long on the Hobby King EPP FPV. Here it is:
Opening the box shows a nicely packaged plane (I’ve removed some of the bubble wrap from the box).
All the major components came individually wrapper in plastic bags. The EPP foam (which stands for Expanded polypropylene) is a larger “cell” than the material the Bixler was made from, but quite light and seems to be relatively strong.
The “fuselage” aft of the wing is a very strong carbon rod. First seen the photo below:
It’s a little hard to see from the image below, but the wing is very true:
The motors I’m putting into the Hobby King EPP FPV is an NTM Prop Drive Series 35-36A 1400Kv / 550W (should be PLENTY of power) :
For servos I’m using Hextronik MG-14 14g/2.2kg/0.11sec aircraft servos:
The ESC is a TURNIGY TRUST 55A SBEC Brushless Speed Controller :
The props for the Hobby King EPP FPV are JXF 9×5 / 229 x 127mm Poly Composite propellers :
Same thing goes for the horizontal stabilizer:
I took this image to show you the amount of room available within the fuselage for batteries, radio, and FPV gear. There’s quite a bit – but this still leaves a very aerodynamic profile. Also the “hatch” has two sections that you can use depending on how you want to configure your FPV gear:
Then from this angle you can really see how big the Hobby King EPP FPV is front to back:
The Building Process
Ok – now I’m going to get into the building of the Hobby King EPP FPV. Frankly it’s quite an enjoyable build. Hobby King hasn’t really specified this as an ARF or anything like that – there is some assembly required, but it is an easy build.
The first thing to do is put in the carbon rods which will serve as the wing holders later. They went in smoothly and were tacked in with a little CA:
Here’s another view – and you can also see the motor mount here:
This is another really clever aspect of the Hobby King EPP FPV design – the servos for the rudder and elevator are mounted to the carbon fiber rod using fiberglass components. Really simple, but a very elegant solution:
The laser cut wood was well shaped and the components went together easily and were attached with a few drops of CA:
The trailing edges of the wing and rear stabilizers are all reinforced with a carbon fiber piece as shown here on the wing (duct tape was just to hold it tight while the CA was drying):
Here you see the laser cut components fixed to the horizontal stabilizer – fits like a glove:
The aileron servos are embedded into the wing. The Hobby King EPP FPV kit comes with control horns which are inserted into slots cut into the ailerons:
This image shows the control horn inserted into the aileron. Once the slot was created they were stuck down with a few drops of CA:
The hardware which comes with the Hobby King EPP FPV seems quite adequate (much more substantial than was included with the Bixler). I did however need to enlarge the holes in the servo horn for the control rod assembly to connect to:
I’m still playing with this, but I’m not sure yet if I am going to install these connectors to the tops of bottoms of the servo horns. Seems like they might be better on the bottom, but I need to minimize the amount of play in the control line. Also, I put a drop of loctite on the threads to keep them from getting loose later in flight:
Here’s a mock up of the motor assembly which I was playing with. The prop connector actually goes on the side of the motor opposite from where the shaft is. This way the outrunner connects to the fuselage via the stator.
Here’s a better view of how the motors connects to the fuselage and how the wires will be run inside the plan. You can also see what I mean about the shaft being unconnected and going into the fuselage:
Final step in this part of the build log is the attachment of these plastic pieces which seem to reinforce the wing where the rubber bands hold it to the fuselage. They got attached using some Gorilla glue with no problem other than holding it curved while the glue dries.
After further tweaking I decided to put the servo push rod connectors onto the plane the correct way (it seems they slop around when the connector is on the side closest to the wing):
The push rod connectors on the rudder and elevator use the same scheme as the ailerons did – put a cut into the surface and glue the connector into place (it is a little hard to see the cut, but it goes into the “H”):
I brought over my radio receiver from the Bixler to try to zero out the servos as they were being installed into the Hobby King EPP FPV:
Here’s a closeup of the servo installation. What is interesting about this is that the EPP FPV has one servo mounted upright and the other mounted upside down:
I made this photograph so you could see inside the fuselage where the motor is installed. The wires are a little bit difficult to install in the Hobby King EPP FPV, but it is possible..
The servo wires (and extensions) which are used for the rudder and elevator are installed in a similar manner to which the aileron ones were. You make a cut into the fuselage and insert the wires (and connectors into the cut):
For size comparison I show the Hobby King EPP FPV next to the Bixler. Yes it is a lot bigger and beefier!
At this point I’m pretty happy with the installation of the rudder and elevator servos – time to tack them in place with some Zap-A-Gap:
The guide tube gets glue into all the holes so the push rod cannot bend under pressure..
I needed to get some screws from the local hardware store, but the motor mounted really easily:
I’ve got two Hobby King Nano-Tech 3S 2200 batteries in parallel to power this plane. Should be some serious juice. If you aren’t already using Nano-Tech – I highly recommending them. Works great with my Tricopter and one of the nice things which you need to know is you can charge them at up to 8C. My charger only goes up to 4 amps, but this is a really nice feature in that you can charge your batteries MUCH faster..
These batteries are great:
Here’s the final plane.. It came out pretty good if I do say so myself!
The Hobby King EPP FPV needs a lot of nose weight to get the correct CG – even with the two batteries..
This has been a really fun build and I’m really looking forward to flying the plane over the weekend!!
Hope you enjoyed this build log.. Please comment!