3D Printed F-104 with 80mm EDF Unit

[telnar1236]

I have always loved the F-104 and built a series of balsa designs about a year ago, but never really got any of them to fly to my satisfaction. Recently, I built a couple of 3D printed planes and decided to try and design an F-104 for LW PLA. Because of the weight of 3D printed designs, an 80mm EDF was about the smallest I could do and achieve the kind of performance I was looking for. The first test was last weekend, but the plane over rotated on takeoff and crashed. Following repairs, I had a successful flight this weekend although I went a bit too far in the other direction and had far too little elevator authority resulting in a hard landing that damaged the gear. When I started this project, I did not know if it would be even remotely successful, but I'm pretty confident now that next time I get to fly, everything will be dialed in as I want it, so I figured now was the time to post. I can post STL files if anyone wants them, but they were a learning experience and are not anything like as streamlined as those commercially available. I chose to fiberglass my plane, but it should not need it and otherwise only two carbon fiber rods are required (1x 10mm and 1x 3mm).

Some specs
Length: 67"
Wingspan: 31" + 4" from tip tanks
Flying Weight: 3.403 kg
Power system: FMS 80mm w/ 100 A ESC
Battery: 5000 mAh 6s
Top Speed: 140 mph designed (clocked at 106 mph during the one flight performed at about 70-80% throttle and without trying for speed passes)

Needless to say, this plane is quite a handful in the air, but it is surprisingly stable for what it is. I did not think to ask someone to video during the flight, but I should get video next time I fly it (hopefully next weekend).

The F-104 after the failed maiden last weekend.

And some building pictures.

 

[Crash Test RC]

that Looks great

 

[telnar1236]

Got in five more flights and the plane was well tuned in and flying nicely. It can actually land very slowly (for an F-104) courtesy of its slotted flaps and with the correct elevator rates it's pretty easy to fly. It cannot quite hit 140 mph and the fastest I ever clocked it at was 123 mph, but for an 80mm edf, I'm happy with that speed.

Unfortunately on the most recent flight, I flew in front of the sun on my landing approach and lost orientation at low altitude resulting in a crash. It should take a few weeks to fix if I decide to do it (I need to reprint and reglass the whole nose section).

 

[telnar1236]

The nose is reprinted. Now needs to be attached to the fuselage and glassed. The e-sun LW-PLA I used is out of stock so I tried using polymaker polylite filament for the nose cone. It turned out about 18% heavier but since the nose cone only weighed 37 grams originally the total increase was only 7 grams (to 44 grams).

 

[telnar1236]

I've been pretty busy and also got distracted by a different project, but I'm back to working on the F-104. I decided to use the damage to the forward section as an opportunity to design a cockpit interior. Because the scale is so similar to the 90 mm F-104 from Freewing, I am using the clear canopy from that model as a new canopy for this one.

 

[telnar1236]

Got in another two flights finally, this time without wingtip tanks. Interestingly, it is substantially slower without the tanks, topping out at 106 mph (it might also be the hotter weather reducing thrust from the fan). I think the most likely explanation is a large increase in induced drag. Since the tanks increase lift for landing and reduce drag at speed I think I need to fly with them in the future.

 

[Sero]

Great work! Any videos of it?

 

[telnar1236]

Great work! Any videos of it?

Unfortunately still no videos. I asked someone to try and film the second flight, but a silver airplane against a gray sky can be very hard to follow, especially when it averages around 85 mph most of the flight.

 

[telnar1236]

Took the F-104 out flying again this morning. It's a bit beat up, but still flies great, even if it rolls off the runway every single time I land. Hit 112 mph with no wind.

 

[CyclicRedundancy]

Hiya,
Any chance I could get the plans/3D files for this? The starfighter is my favorite aircraft and I decided 3d printing an EDF jet will be my next project. I was going to design one myself but after a bit of research I stumbled across this thread. I also plan to build a larger version with a small turbine engine (again 3d print), but the EDF will suffice for now.

Jaden

 

[telnar1236]

Hiya,
Any chance I could get the plans/3D files for this? The starfighter is my favorite aircraft and I decided 3d printing an EDF jet will be my next project. I was going to design one myself but after a bit of research I stumbled across this thread. I also plan to build a larger version with a small turbine engine (again 3d print), but the EDF will suffice for now.

Jaden

Here are the STL files. You're the second person to ask for them so I'll give you the same warning I gave the first person. This is a very advanced airplane to fly. I wouldn't attempt it unless you have a lot of experience with fast unforgiving EDFs. From the fact that you're contemplating a turbine, I think it's safe to say you've been at this for a while, so this warning is mostly for others who might stumble across this. Second, this plane is not well optimized for building. I made the files to let me build it as soon as I could and not necessarily for a good building experience. Finally, glassing the exterior is probably a pretty good idea with this plane. It might work without it, but I glassed it and would recommend anyone who builds it do the same. Also, this plane is not all that scale. I optimized it for speed, and it does that pretty well, but there were some tradeoffs with getting precise cross-sections scale.

As mentioned, the STL files are not well optimized to just be thrown on a 3d printer and printed. Most of the fuselage files should be printed with 2 layers wall thickness and 3-5% infill while most, but not all, of the wing files should have 60-80% infill. As a general rule, common sense needs to be used. Nothing should be a solid block of material, and if something doesn't seem structurally sound it probably isn't. Supports are absolutely necessary for some of the fuselage parts but will make some of the wing parts unprintable. Again, if it doesn't look right, it probably isn't. The smaller hole in the wings and fuselage is for a 10mm carbon fiber spar, and a steel spar and steel tube for the pivot point are needed for the tail. This plane was designed without a lot of the hardware in the STLs since I laser cut most of that. I don't actually have those files anymore (had a hard drive die on me) but they're just hinges and control horns which should be pretty manageable.

If you have questions about how it goes together, feel free to ask. I think all the STLs are included but if a part seems to be missing, let me know and I can check to see if I have it.

 

[telnar1236]

Hiya,
Any chance I could get the plans/3D files for this? The starfighter is my favorite aircraft and I decided 3d printing an EDF jet will be my next project. I was going to design one myself but after a bit of research I stumbled across this thread. I also plan to build a larger version with a small turbine engine (again 3d print), but the EDF will suffice for now.

Jaden

Also, if you haven't seen the thread, I have a 50mm EDF F-104 design as well. It is much easier to fly, much better designed, more scale, and has better documentation of the build process. Smaller planes aren't always for everyone, but I feel I would be remiss in not pointing out that if you just want an F-104, regardless of size, there is a better option than this one.

 

[CyclicRedundancy]

Yessir.
I took a look at the 50mm variant you mentioned. Great job, hope to see flight footage soon! I have given it some thought and I think I will honestly try my hand at designing a large f104 (100mm fan or so) size, so I can just test with the EDF then drop in the turbine straightaway. I would preferably have the f104 as large as possible (as a heli guy the larger aircraft are always a heck of a lot more stable and look way cooler, and have more space to do paint detail on). Hopefully I get it done sometime this year. Anyways, I will be following both of these threads, please post some video of it flying!
Jaden

 

[telnar1236]

Yessir.
I took a look at the 50mm variant you mentioned. Great job, hope to see flight footage soon! I have given it some thought and I think I will honestly try my hand at designing a large f104 (100mm fan or so) size, so I can just test with the EDF then drop in the turbine straightaway. I would preferably have the f104 as large as possible (as a heli guy the larger aircraft are always a heck of a lot more stable and look way cooler, and have more space to do paint detail on). Hopefully I get it done sometime this year. Anyways, I will be following both of these threads, please post some video of it flying!
Jaden

That's almost certainly the right decision. I hope you'll post you're build process. We need more F-104 designs out there.

 

[CyclicRedundancy]

Hello again.

After giving it some thought I think I'll try my hand at this 80mm starfighter, haha. I was contemplating building the 50mm but the big size is too attractive.

I'm going to buy some more filament, as it's a large print, do I have to use LW filament or can I just use regular PLA? And is it possible to fly it (gently) without glassing the fuse? If you don't know I guess I'll try it just superglued together and we'll find out.

As for the power source my father is building his own 3d designed plane currently sporting a 3S 3300 kv or so motor with his own edf fan/stator design. We'll see how it powers that and then decide on the powerplant for the starfighter.

As for all the extra hardware needed (wheels, spars, carbon fiber tubes, hinges, etc) do you have a parts list? I recall from your 50mm blog you needed to build balsa wings, and a system for operating the elevator using laser cut parts(I think). Is there anything like that in the 80mm one?

Thanks for the help and hopefully I will get to build this soon.

Jaden

 

[telnar1236]

I'm going to buy some more filament, as it's a large print, do I have to use LW filament or can I just use regular PLA? And is it possible to fly it (gently) without glassing the fuse? If you don't know I guess I'll try it just superglued together and we'll find out.
Jaden

The filament definitely needs to be LW PLA. It's about 1.5 rolls. The weight of the print would more than double with normal PLA which would not be good for obvious reasons. I believe the gear struts are the only normal PLA parts. The aircraft needs some kind of reinforcement. If you don't fiberglass it, I would recommend running fiberglass or carbon fiber rods down the full length of the fuselage. No guarantees it would work, but it gives you a fighting chance to not have it break into pieces.

As for the power source my father is building his own 3d designed plane currently sporting a 3S 3300 kv or so motor with his own edf fan/stator design. We'll see how it powers that and then decide on the powerplant for the starfighter.

I used an 80mm FMS fan powered by 6s with a 100A ESC that supplies about 3.5 kg of thrust. You could get away with less, but I'm not sure a 3s power system is going to cut it. It would be neat if it works though.

As for all the extra hardware needed (wheels, spars, carbon fiber tubes, hinges, etc) do you have a parts list? I recall from your 50mm blog you needed to build balsa wings, and a system for operating the elevator using laser cut parts(I think). Is there anything like that in the 80mm one?

It's been a while since I built this, but I think this is the list of hardware. There isn't anything you cannot do without laser cutting for either one, but more of the 80mm one is 3D printed.
- 10mm carbon fiber rod - wings
- 3mm hardened steel rod - H stabilizer
- 3mm ID steel tube - H stabilizer pivot
- wheels - size to struts - not designed for one particular size
- nose gear strut (main gear struts are 3D printed)
- nylon hinges - rudder, ailerons
- hinges for flaps - I used laser cut hinges to make slotted flaps but these are not included in the model
- control horns - flaps, rudder, elevator, ailerons
- battery tray - I laser cut this it glues down all the way forward in the battery compartment
- control linkages - I used 1.5mm hardened steel rods for this on everything but the elevator where I used a 2mm hardened steel rod

There might be a couple items missing from the list since, like I said, it's been a bit since I built it, but I think that's all.

 

[CyclicRedundancy]

Definitely. I'll wait until you post some flight footage first then I'll dive in. Got a lot of projects going on at once, LOL. I have this custom built fiberglass P80 that needs a new edf unit (I think 80mm) and a bunch of other prop planes that I need to fix up.

I'm very excited for the video of yours flying!! Thanks for taking the time to make such a detailed response.

Jaden

 

[telnar1236]

Definitely. I'll wait until you post some flight footage first then I'll dive in. Got a lot of projects going on at once, LOL. I have this custom built fiberglass P80 that needs a new edf unit (I think 80mm) and a bunch of other prop planes that I need to fix up.

I'm very excited for the video of yours flying!! Thanks for taking the time to make such a detailed response.

Jaden

Glad the detailed response was useful.

In terms of flight video of this one, you might be waiting a while then. I've attempted to get video of it 3-4 times and it never comes out usable since it's fast, silver, hard to track, and I keep it high to avoid crashing most of the time. I've pretty much given up trying at this point. I also fly it rarely since it's only really fun when I'm in the mood for some adrenaline and a challenge. I plan on getting video of the 50mm one since it should be easier to track, so that might be coming up in the next several weeks.

 

[Robf1967]

That’s a pretty awesome build… you know the U2 was based on the F104… if my CAD skills were better I’d be swizzling up some U2 wings

 

[Matthewdupreez]

Also, if you haven't seen the thread, I have a 50mm EDF F-104 design as well. It is much easier to fly, much better designed, more scale, and has better documentation of the build process. Smaller planes aren't always for everyone, but I feel I would be remiss in not pointing out that if you just want an F-104, regardless of size, there is a better option than this one.

could you please share the link to your 50mm f-104 ?
i can't seem to find it lol