Goblin86 Long Range / Cruiser


Elite member
I really love the size of the 75% Goblin by JUSS10 and have built a few of those, but then I started looking for more of an endurance build and started making modifications. After 4 or 5 different iterations, I've ended up with this model, which has now flown over 500 cumulative miles!

  • Fuselage width reduced by 17%, still room to mount a 30x30 flight controller
  • Reduced fuselage tail area, by 10mm vertically, 4mm horizontally to fit 12x12 mount motors more closely
  • Reduced wing thickness by 25-33%, removed undercambered wing tips
  • Increased wingspan by 10%, wing area by ~20% (can't recall exactly)
  • Redesigned vertical stablizers for smaller size and more prop protection
  • Cutouts in wing to fit 30x30 FC and space to put an ESC near the vent holes in the back
All these changes add up to a 2S-carrying model that sips under 0.6Wh/km cruising at 50kph (around 80mAh/km for 2S). My usual flights are around 12-13km total distance on a 1300mAh 2S with the longest flight being 15km on that battery while weighing in at just 235g with full sized FPV gear on board. An 18650 2S pack can go ~35km round trip or more! Top speed is about 90kph pulling 12-13A but my intention with this was not to make a ripper.


  • EMAX 12A ESC
  • Cobra 1407 3500KV motor, also fits 1606 motors
  • Gemfan Windancer 4032 (x3) prop although a HQ 4x4.3x3 pulls slightly less current, slightly lower speed, equal efficiency
  • 2x Turnigy TGY-1551A 5g servos
  • ExpressLRS EP1 RX (mounted in hollow of wing)
  • Omnibus F4 Pro V2 flight controller
  • Rush Tank Ultimate Plus 800mW VTX
  • Caddx Ratel 2 Starlight micro camera
  • Lumenier Micro AXII Shorty 5.8GHz antenna
  • BN-180 GPS
  • 170g dry weight, 235g with 1300mA 2S, 270g with 2S 18650
  • 130g dry weight with no FPV gear or FC (ESC+Servos+PWMP RX)
  • CG: Around 10-20mm from leading edge
  • Wingspan: 660mm
It is hard to say how far it can go as I live in Florida where everything is flat and there's wet tall trees everywhere so the signal gets blocked pretty easily, but even with a EP2 ceramic antenna I was able to go 4.5km on 250Hz 100mW of output power. With the EP1's dipole antenna I get over 5km but I start losing LOS and the signal drops off pretty fast so that's as far our as I've taken it. With clear LOS it is possible it could go 30-40km on 2.4GHz, that's the beauty of ExpressLRS. Unfortunately the largest battery thing thing can hold will just get you out that far, not back! 😆

The electronics are accessed with just the top flap having a tape hinge on one side and a piece of tape to hold it shut. Make a little handle on the tape by folding the edge so you can grab it to open it up, and use another piece of tape on the fuselage to provide a good place to stick to without peeling the paper. The front hatch also is just a tape hinge and if you cut it right it fits well enough that it won't open in flight, but a rubber band over it works too.

DSC07740.JPG DSC07733.JPG

The plans have just a round foam nose, but also have a line where you can stop cutting and skip all those annoying curvy cuts and just use a 3D-printed nose with screw holes to mount the camera easily. This went through a lot of different versions, starting with just a reinforcement that went inside (because I bonked into a rock on landing once and broke my lens) to finally just removing the nose entirely and replacing it. Between the double layer of foam and glue and stick to hold it in place, the fully 3D printed nose ended up being slightly lighter than the original and sure is a lot easier to make. Nose and firewall 3D printed parts are on Thingiverse

When you load it up with all this extra hardware, it starts to get a little heavy. Just this plane with no FPV / FC / 950mA 2S is going to run you under 200g and can really slow down, but at 235g the stall speed is around 32kph / 20mph, and with 18650s it is around 37kph so it wants to land fast. With the CG in the perfect right place (somewhere around 20mm) it will just descend when it stalls so no big deal, but with a safer CG (10mm), the nose will bob up and down as it stalls and may cause Sudden Landings if you come in slow. The model is so light though that I've never had a problem with damage coming from a landing stall, the moist grass is a larger threat.

This all still fits on 1 piece of DTFB. The wing is just cut as one piece, and some weight can be saved by peeling the paper off the inside wing surfaces anywhere they aren't exposed / control surfaces. I didn't need any reflex in the elevons, or at most 1mm of reflex. There's no thrust angle on the motor and it behaves really well without pitching wildly when jumping to full throttle, most likely due to the low amount of thrust generated even at max.

EDIT: How does it fly?
Can't believe I forgot to include this information! I think it flies better than most FPV wings in this size range I've see on youtube. It has no yaw waggle, the wings are pretty stable, and it is somewhat agile. With a 60/40 split for pitch/roll and low throws, it will still roll at 400degrees/sec and pitch at 180degrees/sec. It lacks power to loop at cruise throttle though so for loops expect to do 85-90% throttle to have any chance of success. Otherwise it sort of gets to 45-80 degrees of pitch and just gives up. Inverted flight is not a problem at all.

There's a gentle stall characteristic and I've never experienced a tip stall. It can also turn on a dime due to its light weight, but steep climbs (like loops) you'll need to pour on the power.


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New member
Just maidened. Winds was quite strong and freezing, but everything went very smooth. After 15 minutes my fingers become too stiff. Now waiting for next session and, probably, better weather. Like it very much. My first foamboard plane BTW.
Thanks for creating and sharing.
* ZMR 1804 2300kv
* Gemfan Apc Nylon 5x5 prop
* 10 Amp ESC, RCX (probably, found in box)
* EMAX 4.3g servos
* Lefei Sparrow 2-OSD
* Eachine TX805
* 3s 1Ah
AUW 318g


New member
Couple of hundreds of km behind the prop.
Love this plane. JUSS10, CapnBry and all folks involved, thanks for that. This is what I was looking for some time.
Average session - ~20 minutes, 13-15 km total distance, 700-800mAh on 3s, carrying 1Ah battery, cruising ~2.5A (all according to FC data). It's still cold outside, therefore mostly one battery per session. Despite warm TX muff and fingerless gloves, fingers looses their flexibility during session.
Bottom of the fins are wearing out on icy-snowy, sometimes wet snow landings, I did not strengthen them by glue or tape, my bad.
Figured out some more assembly flaws, as soon as it's my first foamboard built.
Probably foamboard, available for me is bit different, as in FT build videos. To remove paper layer it has to be cut off by knife, it does not peel off. Also it seems it has much harder foam.
For the next one (there will definitely be continuation), probably, I will make fuselage bit wider (~5mm) to accommodate two 18650 side by side and third on top. Intention is 3s Li-Ion for longer flights. But before will test with existing battery (~100g) and additional weight (~50g) to check carrying capacity of the wing. Probably will become more speedy and more mAh consuming because of ~15% more AUW.
Not done yet, but there will be headtracked pan camera. I have one on other plane, it is so exciting, but now GOBLIN86 is The Plane I am flying.
Some more thoughts on subject. For the next iteration I will leave wing tip square (keep in mind foamboard available to me, it is hard and bends bad) and will think about small, thin (some plastic?) winglets just to reduce drag.


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Elite member
Awesome! Glad you like the design, I've flown it probably more than anything else I've ever made and made like 8 of them now with small changes every time. On the latest iteration I used two popsicle sticks in the nose instead of the double layer to get some more room in there, but it still doesn't fit 18650s which is a shame. I was planning on making the next one scaled up a bit so they will fit, but then I wanted to scale it up enough to fit 21700s and then I thought change the motor to a 2306 I have... and it started to seem like too much work 😀

I tried changing the wings to be closer to the size of the original STRIX Nano Goblin too, 175mm chord (15mm larger) but a 600mm wingspan (60mm smaller). It seems to have more pitch authority, but seems to waggle a bit more. The wings are also solid to the tips because you're right about that too, the thin tips just get bent up too easily. I'm not sure what the next iteration will be, but I'll probably bring some of that back to the Goblin86 design instead of building on this wing shape.


New member
Again some thoughts. (I am not an aviation engineer, please do not judge too strong.) Increasing chord and decreasing wingspan will increase drag. Also increasing chord it would be wise to increase thickness of the wing, but in our case it means step, one ore two layers of foamboard in the middle. Thicker wing = more drag, but more lift. To my opinion you reached some good balance in wingspan. chord and thickness with the present wing. It is quite efficient. The smaller thickness of the wing and greater wingspan in comparison to 75% version and still on one piece of foamboard was the point bought me. (And, of course, I discovered, that there is foamboard at last available there.)
Will wait for bit warmer weather there and will start experimenting with loading. I hope increase in AUW (~+50g) to accommodate three 18650 will be acceptable for the present wing. At present form the wing is so nice to fly, I am bit nervous on adding extra ~50g, how will be its new behavior. Also bit wider fuse will add a bit of drag, but if wing will bear three 18650, the flight time should be much longer.

(Last winter I crashed my ZOHD Drift due to Li-Ion battery. It was cold and I took off and headed for usual voyage ~1.5km from take off point. After few minutes of flight Drift started to descend. There was not enough power, however voltage was quite high. Fortunately, battery left connected, video still broadcasting. I drove closer to last viewed location with working googles and when some picture appeared went out and with radio bearing method found it. After repairs I made the same pattern with LiPo, no problems. With 2s LiPo flight time is around 15-20 minutes, with 2s Li-Ion after 40 minutes there is still much juice left in batteries. Up to now never drain them "dry".)

I'd make some tests to see whether wing will be able to carry weight in case of three 21700 (65-70g each) and heavier motor. Landing speed should notably increase. May be wing thickness should be increased to increase lift? In my case with AUW ~320g, with 1804 2400kV ZMR motor and 3s battery (~100g) it seems landing / stall speed is greater than in your case as you said in the first post. My cruising speed is around 45-55 km/h with 2.5-3.5A current.

There could be the way to increase lift by decreasing reflex, but in this case new element should be added - separate horizontal stabilizer (twin boom?) and as further it is placed as smaller it can be, but again, added drag. And it will not be the Plank any more.