Hobby King EPP FPV

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:

Reading over the manual – you need to be careful what you declare this as when you order it from Hobby King as “Body Parts included in packaging.”  May get caught up in customs otherwise…  😉

Also they included a little Jedi magic in the box with the enclosed “mental adjuster.”

Now I’m just joking of course.  Actually the instruction manual is pretty good (other than a few funny typos)…  It’s in color and goes step by step through the assembly.

It’s a little hard to see from the image below, but the wing is very true:

Here’s another image showing all the “body parts” :

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 :

Just to give you a feel for the build accessories – laser cut wood and carbon fiber rods are used extensively as well as glass fiber components for the servo holders and control rod horns:

Here’s the vertical stabilizer – as you’ll see the hinges are vees cut out of the foam.  Quite a good idea and seemed to work well on all the surfaces:

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:

Here’s me doing a mini mock up to get a sense of how the model goes together early on:

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:

The carbon fiber rod is really strong and fit snug within the main fuselage:

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 horizontal stabilizer slid right onto the main carbon rod and then I connected the vertical stabilizer on with some Gorilla glue.

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”):

The Zap-a-Gap takes some time to set, so I needed to put a little pressure on the surface to give it time to dry:

Back to the installation of the rudder and elevator servos onto the Hobby King EPP FPV – here you can see how the elevator servo gets mounted:

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:

Tack away!

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!

22 Responses to Hobby King EPP FPV

  1. Pingback: Continuing with the Hobby King EPP FPV Build | ILoveFPV.COM

  2. tj says:

    It’s looking quite good so far.
    Mine still in box awaiting some parts.
    😀

    • Al says:

      You get your FPV gear yet Tj?

      -Al

      • Steve says:

        Yes!! Check out the home page to see the FPV camera mount and first videos…

      • tj says:

        Elo Al,

        So far I have:-
        Camera arrived today.
        Just awaiting the Servo’s and prop (should be here tomorrow)
        Fatshark 600mw Vtx (Sat in customs for the past 4 days 🙁 )
        Cyclops Nova osd with autopilot / rth

        Will be able to test soon, osd might be a week or so away.
        But I’ll be able to test once the vtx arrives.
        Need to rewire the camera though 🙁

        Have you signed up to Steve’s forum Al?

        🙂

        • Al says:

          Hi Tj!

          Sounds great, you should be able to get some extreme range with that! Especially with the RTH to bring you home if you go a bit far 🙂

          I managed to bust my 200mw 5.8G transmitter somehow, so no FPV for me for a little while… Need to decide whether to get a Fatshark compatible transmitter for my goggles (Dominators or Predators?- I can’t decide) or just another cheapie Foxtech transmitter…

          I haven’t actually signed up to the forums yet (Sorry Steve!), I’ll go and do that now 😀

          Happy flying!
          -Al

          • tj says:

            Pretty much done now.
            Just got to sort out the servo wires.
            I’ve mounted my motor slightly different though.
            Rather than feed the wires through the hole on the mount, I’ve mount my motor so the wires are at the bottom of the mount, made a hole in the fuse and fed them through that way.
            The only reason I did that, was to leave the hole next to the motor to expel heat build up from inside.
            How well it will work is another matter though lol.

            600mw tx arrives tomorrow, so can start getting the camera setup done.

            Although I do seem to have a lot of flex in the control rods, and not a lot of movement of elevator.

            😀

  3. Steve B says:

    Thanks for the photo update. One gets the sense the EPP is much beefer than the Bixler just by looking at the control linkages that come with the kit. Looking forward to see its maiden flight and finally its use as a FVP platform.

  4. Pingback: Hobby King EPP FPV – Almost there…. | ILoveFPV.COM

  5. Steve says:

    @TJ – what’s missing?

    • tj says:

      Motor, servos, it’s a case of awaiting mr postman.
      Fpv wise, I’m awaiting the fatshark vtx, camera.

      But weather has done nothing but rain for past 2 weeks, and looks set to continue to rain.

      🙂

  6. Steve says:

    @Steve B – it most certainly is! And it is 2X the size… Yes, I’m getting excited about the maiden as well…

  7. Pingback: Hobby King EPP FPV Build – Complete! | ILoveFPV.COM

  8. tj says:

    Can’t wait to see the flight vids Steve.

    Well I’ve had to order another one.
    I’m still awaiting the motor and things to arrive.
    Why does it seem like months to deliver when the parts are for you lol.

    But whilst waiting I had a phone call to see if I had any instock.
    So ended up selling mine, and ordering another.
    But can guarantee the plane will still turn up before motor etc.

    Regards
    Tj

  9. Keven says:

    I actually just started a EPP FPV build myself. And I purchased the exact same motor that you did. However I cannot seem to find the prop adapter and the base plate to attach to the firewall.

    Would you happen to have a part number for these two parts?

    • Steve says:

      Hi Keven –

      I just returned from business… Did you get the answer or do you need me to look it up?

      Thanks,

      Steve

  10. Naro says:

    Thanks for documenting and publishing this! You rock!
    Quick question, I’m new to r/c & FPV’ing…
    So after a basic research I decided to get into FPV with this EPP model.
    Before I order it I wanted to make sure I’m also ordering all the parts I need to put it together…

    Here’s what I have in the shopping cart:
    1Plane
    1Motor
    2Propellor
    1Battery (5000 nano tech)
    4Servo
    1esc

    Is that everything I’ll need to get it ready to fly?
    A friend of mine said he has a 4channel controler he said he’ll give me…

    Thank you!

  11. Steve says:

    Naro – looks good to me !

  12. Jon Hogan says:

    I purchased the same for my first FPV plane and it is also the first plane I have had since the 1980’s lol, I was wondering what you set the CG at? The manual says two different settings 45-55mm and 200-220mm, I tend to think it is the 45-55mm I think the other is way to far back but thought I would ask.
    Thanks
    Jon

    • Steve says:

      Hi Jon,

      It’s been a while, but I think you’re right about 45-55mm. Is this ~ 1/3 back from the leading edge?

      The manual is very poor and looks to be a bunch of copy/paste from another model. There are some pretty funny typos in there too.

      Hope this helps,

      Steve

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