*Unofficial* FT Goblin

[jaredstrees]

Half an inch reflex is a lot. My reflex is nowhere near that and she flies great. the bottoms of my elevons are maybe 3mm above the top of the wing. They do mention you need reflex, and they say it should be bottom of elevon is level with the top of the wing.

 

[JUSS10]

I have my reflex set so the bottom of the elevons it level with the top surface of the wing right by the fuselage. That seemed to work well for me. CG will obviously affect it, so make sure its well balanced first, then set the reflex, take it for a spin and see how much trim is needed. Land and correct if necessary.

 

[EDinCT]

Great point about the reflex. I didn’t even think about it and I went in on the first flight too. No damage though. I just built my second goblin using the WR foam. Here is my reflex:

 

[CarolineTyler]

Cut out yesterday evening, built this morning, flown this afternoon. What a fab plane!!!!

 

[mrjdstewart]

maybe tomorrow? monsoon rain's are fighting the plan currently, we will see by morning. cross fingers.

me

 

[Edwardchew]

New flight at a much bigger airfield so i can stretch her!

 

[Morgan]

Just maided mine today and wow such a nice flying plane!

 

[Edwardchew]

I made a 1300mm FT Goblin!

 

[Airkaos]

My maiden didn’t go too well..

t

 

[tamuct01]

I used the standard F pack Flite Test kit and didn't have much luck. The F pack comes with the 2204 motor and 12A ESC. I have a XT30 to XT60 adapter to run my standard 2200mAh 3S packs. On the bench at full throttle it was hitting 12-12.5 Amps and the motor started to stutter at full throttle. Assuming I'm hitting the upper limits of this ESC, I told myself "just don't stay at full throttle very long." The maiden started ok, but less than 30 seconds into the flight at 3/4 throttle I could hear the motor stuttering. I pulled the throttle back a little and it kept going, but I decided then it was time to bring it in. As I continued on my downwind turning to base I could hear it stuttering more -- pulled back to 1/2 throttle. From base to final it stuttered more -- pulled back to 1/3 throttle. I was able to successfully land it, but I immediately ordered a new 30A ESC, motor, and prop for it. I'm not sure whether it's the ESC or motor, but something is up with this power setup. Fortunately, I saved the Goblin for another day.

 

[CapnBry]

Yeah the Power Pack F 6x3 prop I think is a little big for a 12A ESC. Plugging it into eCalc, I get a max current draw of 14.1A on 3S. I ran an RS2205 with the 12A ESC and it also was not too happy about it so I limited my throttle to 80%, which measured out to 9.5A in reality. The prop's not very good for 2S either though, maxing out at 280g of thrust / 8A at full power. Better prop fits seem to be a 6x4 for 2S at 344g/9.3A and 5x3.5 for 3S at 435g/10A.

I have to say this Goblin flies really well and is a ton of fun. I scratch built one and kinda messed up the wing cutout assembly so I had one wing dipped lower that the other with respect to the fuselage. Not a big deal to fly with a slightly rotated body though, right? :-D Actually that appears to be true because it flew just peachy. I didn't bother to paint all of it because I am about out of spraypaint and just wanted to make sure the control surfaces didn't warp when they land in the swamp here.

If only it could make me a better pilot though. I cut hard into a low turn and it was clear that I didn't have the speed to keep it level so I gunned the throttle. Blackbox says at the same time I relaxed on the up elevator which didn't help my situation and I ended up with my Goblin looking like many in this thread. The time from throttle up to impact at full throttle, under 0.7s.

This was so much fun to fly I will definitely fix it up and fly it again but I kinda want to get more pro-looking version. I just can't decide on an FT speedbuild kit, a Strix Goblin or a Strix Mini Goblin. Has anyone 3D designed a side plate that can be sandwiched between the doublers and fuselage to give them more strength? A 0.5mm thick band of plastic glued in between them could help to spread out the force of nose-in cartwheels.

EMAX RS2205-2300KV motor, 20A Flycolor Raptor F390 ESC, 1000mAh 3S battery, Lumineer 5x3.5 prop, Omnibus F4 Pro V2 flight controller, 9g SG90 servos - 159g empty (no servos/motor/mounts) 382g all up weight

 

[foamtest]

I recently got a nano goblin and that thing is very durable and I kinda want a larger foam board one that is just as durable. I might have to do some experimentation with foam board and possibly plywood doublers in the nose. (since nose weight isn't an issue with this particular bird.) I have to work a lot this week so maybe this weekend if I'm off.

 

[docque]

My maiden didn’t go too well.. View attachment 114120 t

That is exactly what mine did. Not going to rebuild due to the weak structure.

 

[CapnBry]

I created those reinforcement bands I was talking about, available on Thingiverse. Just slip one of these over each wing hole between the Fuselage Internal and Fuselage External when gluing them together.

With 6mm width and 0.5mm height, you're looking at about 3g although the backs could probably be cut off to save weight. There's also an option to generate an internal profile that can be used as a template for cutting the wing slots for scratch builders, if you'd prefer an inner profile instead of the outer version shown above.

 

[SP0NZ]

I finally finished my FT Goblin this past weekend. I snuck out to the field tonight for the maiden. The thing flew straight as an arrow on the first launch. I'm really impressed with how it flies. This is a plane I can keep in the back of the car and take out for a few quick flights whenever I get the chance. I'm going to have to add some color to this one and make it look nice now. Also need to outfit it with some FPV gear once I get some new goggles. Looking forward to having a lot of fun with this one.

 

[tamuct01]

Here's mine after replacing the power pack F guts with the Lumenier 30A BLHeli ESC, Xnova Lightning 2207-2300kV, and Dal Props 5x5x3. I tested it on the bench and the combo draws about 20A at full throttle from my old Turnigy 2200mAh 3S packs. I'm hoping the second flight goes much better than the first.

I have the Eachine camera and VTX system installed, but I likely won't use it until after a few good line of sight flights. If anyone else could use the STL file for the camera mount, it's on Thingiverse.

 

[Edwardchew]

Yeah the Power Pack F 6x3 prop I think is a little big for a 12A ESC. Plugging it into eCalc, I get a max current draw of 14.1A on 3S. I ran an RS2205 with the 12A ESC and it also was not too happy about it so I limited my throttle to 80%, which measured out to 9.5A in reality. The prop's not very good for 2S either though, maxing out at 280g of thrust / 8A at full power. Better prop fits seem to be a 6x4 for 2S at 344g/9.3A and 5x3.5 for 3S at 435g/10A.

I have to say this Goblin flies really well and is a ton of fun. I scratch built one and kinda messed up the wing cutout assembly so I had one wing dipped lower that the other with respect to the fuselage. Not a big deal to fly with a slightly rotated body though, right? :-D Actually that appears to be true because it flew just peachy. I didn't bother to paint all of it because I am about out of spraypaint and just wanted to make sure the control surfaces didn't warp when they land in the swamp here.
View attachment 114226
View attachment 114228

If only it could make me a better pilot though. I cut hard into a low turn and it was clear that I didn't have the speed to keep it level so I gunned the throttle. Blackbox says at the same time I relaxed on the up elevator which didn't help my situation and I ended up with my Goblin looking like many in this thread. The time from throttle up to impact at full throttle, under 0.7s.

View attachment 114227

This was so much fun to fly I will definitely fix it up and fly it again but I kinda want to get more pro-looking version. I just can't decide on an FT speedbuild kit, a Strix Goblin or a Strix Mini Goblin. Has anyone 3D designed a side plate that can be sandwiched between the doublers and fuselage to give them more strength? A 0.5mm thick band of plastic glued in between them could help to spread out the force of nose-in cartwheels.

EMAX RS2205-2300KV motor, 20A Flycolor Raptor F390 ESC, 1000mAh 3S battery, Lumineer 5x3.5 prop, Omnibus F4 Pro V2 flight controller, 9g SG90 servos - 159g empty (no servos/motor/mounts) 382g all up weight

I'm surprised how you guys can balance it with 3S 1000mah? im on 3S 2200mah and i have to pull it all the way forward that i dont have any space left for camera. haha

 

[CapnBry]

I'm surprised how you guys can balance it with 3S 1000mah? im on 3S 2200mah and i have to pull it all the way forward that i dont have any space left for camera. haha

My battery might weigh half what yours does, but I can turn it sideways so all the weight is at the maximum distance from the CG so the bigger battery is only 1.4x as effective as a counterweight (as opposed to 2x). I also have 17g of weight on the tip of the camera mount . Maybe my motor is lighter too (29g)? That could make a huge difference.

I thought I was going to have to put both 1000mah batteries in it to balance it out given how big the batteries in this thread are, but was pleased it balanced out so easily. I don't think it would even need the weight I added if I pulled the paper off the inside of the wings when I was building. That would lower the wing weight by maybe 20g.

EDIT: And just gluing the nose back on worked like a champ, along with a couple skewers for structure. It held up really well for a second day of flying. Unfortunately I landed a few times at my field, which is a swamp, and the nose ended up absorbing enough water to become a droopy soaked mess that fell apart in flight. Maybe I should have painted the whole thing, eh?

 

[lrussi750]

I finished the build 2 weeks ago and have not had the free time or the weather to try and fly her yet. T-Motor F80 1900kv motor, T-Motor F45a ESC , HQ 6x4.5x3 prop (might try a APC 6x5.5), CNHL 2200 4s 55c battery.

With the 4s battery I have to mount it close to the wing to hit the CG, I tried a 2200 3s and I have to have to mount the battery further forward into the nose area where the FPV camera would be.

 

[Edwardchew]

My battery might weigh half what yours does, but I can turn it sideways so all the weight is at the maximum distance from the CG so the bigger battery is only 1.4x as effective as a counterweight (as opposed to 2x). I also have 17g of weight on the tip of the camera mount . Maybe my motor is lighter too (29g)? That could make a huge difference.

I thought I was going to have to put both 1000mah batteries in it to balance it out given how big the batteries in this thread are, but was pleased it balanced out so easily. I don't think it would even need the weight I added if I pulled the paper off the inside of the wings when I was building. That would lower the wing weight by maybe 20g.

EDIT: And just gluing the nose back on worked like a champ, along with a couple skewers for structure. It held up really well for a second day of flying. Unfortunately I landed a few times at my field, which is a swamp, and the nose ended up absorbing enough water to become a droopy soaked mess that fell apart in flight. Maybe I should have painted the whole thing, eh?

Ahh i see. Ya you're right bout the battery. my 2200mah is long so can only be mounted straight. and im using a bigger 2212 2700kv as opposed to those small 2208 mini quad motors. still... the power/speed is hell lot of fun