XF VIPER - Foamboard F-16 EDF

[Chuppster]

Okay, I finally was able to finish the build. I can honestly say that was possibly my favorite maiden ever. I enjoyed it so much I immediately grabbed another battery and put her right back into the air! Here's some pictures:

I did my battery hatch by adding some support to the center of the opening (to keep it from bowing out) then putting some velcro on the back of the hatch. The front is tucked under the paper from the nose piece.

I made a battery tray out of two pieces of foamboard stacked. It seems to work really well! I also added a NACA duct for electronics ventilation.

Now, for things I don't like (gotta get the bad out of the way...). I found it to be a major pain to attach both "halves" of the fuselage. I don't have suggestions for how to do it better but I'm hopeful that we can find another way. Also, some kind of former for the intake would be helpful for me. I had to make two of them after I screwed up the first one. Another complaint is that the roll rate isn't quite what I enjoy. I love jamming the sticks left or right and seeing the model rotate 900 degrees/second. Seeing as this doesn't have ailerons, though, I suppose it's forgivable. Finally, I think we could move the servos inside the fuse to secure them a little better. I would have, but that would have required planning ahead and I failed to do so (you would have to install the servo wires before you install the motor).

Okay, time for the stuff I like. Can I start with the looks? Man, I'm quite satisfied with the design! I mean, I saw the photos and though "this is cool," but then I build it and I think to myself "dang, this thing looks amazing!". Next, I'll talk about the glide slope. Wow, I did not expect this. It glides for DAYS (for an EDF). I'm used to landing my jets by more or less controlling the fall, but not so with this beauty! Then there's the control during a stall. It's so nice!!! I got in trouble and found that I could still tell the airplane where to go. That's not common among the airplanes I typically fly, so I say A+! And, because it has a nice glide slope, I can fly it, even loop it, at half throttle. Now, I do have an FMS motor that draws 60 amps on 4s (1000w...) on a 12-blade, but I very much enjoy that I can cruise around for awhile before my battery drains 100%. This is by far the best EDF I've flown hands down (so far at least), and I very much look forward to enjoying it for as long as it holds together. Also hoping paint doesn't change its flying characteristics...

@Mid7night, thank you for sharing this bird with us. As it stands, it's amazing, and if you continue to iterate a bit and improve it's going to be awful hard to beat. You are a wonderful asset to this forum and I appreciate your designs.

 

[JTarmstr]

Hey @Mid7night I bought 3 of the EDFs you recommended that were on sale, could they power this? It says they are 5 bladed and the recommended EDF is 12 blades? The viper is my fav U.S. military fighter and I really want one

 

[Chuppster]

Hey @Mid7night I bought 3 of the EDFs you recommended that were on sale, could they power this? It says they are 5 bladed and the recommended EDF is 12 blades? The viper is my fav U.S. military fighter and I really want one

I was really close to buying those EDF's too. I saw, however, that they are only rated at 400 watts. I bet you could get away with them on a small battery, perhaps while exercising some lightening techniques. I, personally, wouldn't build this jet with less than 600 watts of power.

 

[JTarmstr]

I was really close to buying those EDF's too. I saw, however, that they are only rated at 400 watts. I bet you could get away with them on a small battery, perhaps while exercising some lightening techniques. I, personally, wouldn't build this jet with less than 600 watts of power.

ohh ok. guess I am gonna have to put a 70 mm EDF on my wishlist

 

[Mid7night]

Hey @Mid7night I bought 3 of the EDFs you recommended that were on sale, could they power this? It says they are 5 bladed and the recommended EDF is 12 blades? The viper is my fav U.S. military fighter and I really want one

I was really close to buying those EDF's too. I saw, however, that they are only rated at 400 watts. I bet you could get away with them on a small battery, perhaps while exercising some lightening techniques. I, personally, wouldn't build this jet with less than 600 watts of power.

As Chuppster said, if you keep it light - don't do extra fillets of glue everywhere, keep the "smearing" of glue to a minimum, use a smaller battery - it should be fine. You don't HAVE to have a 5000mAh 4S and a 12-blade EDF to fly this bird, that's just what I have a lot of.


@Chuppster:

Thank you for your kind words, AND your appropriate critiques! I'm SO glad to hear the maiden and flights went well, that's the best part.

YES: The fuse-joining step needs some "help", along with some of the others you mentioned. The inlet forming is actually one of the easier steps, but that's where a build video showing the order and how I place things would really help. It's on my (ever-growing) to-do list.

The roll rate can be punched up quite a bit, even with the elevon-only controls. The latest one I've built here at home has MUCH more throw than the ones I built and flew in Ohio, and it is QUITE responsive.

As for servo placement: Are you more concerned with their secure attachment, or with them being visible? Moving them inside the fuse where they are would make the pushrod-angle a bit extreme, but there is probably something I could do about 'securing' them where they are on the outside. The thing I actually LIKE about just sticking them on and gluing them down is that it makes setting up the elevons much easier. You can hook up the surface control horns and attache them to the servo arm with simple Z-bends, then just glue the servo down while holding the elevon surface in its centered position. But that can be improved upon.

It is absolutely my pleasure to share this stuff with you all, and watch and see what y'all do with it! I appreciate every little insight from your personal builds, I will do my best to take the good and improve the plans as we move ahead.

 

[Chuppster]

As for servo placement: Are you more concerned with their secure attachment, or with them being visible? Moving them inside the fuse where they are would make the pushrod-angle a bit extreme, but there is probably something I could do about 'securing' them where they are on the outside. The thing I actually LIKE about just sticking them on and gluing them down is that it makes setting up the elevons much easier. You can hook up the surface control horns and attache them to the servo arm with simple Z-bends, then just glue the servo down while holding the elevon surface in its centered position. But that can be improved upon.

Looks definitely factor into my desire for putting them into the fuselage .

I too enjoy the simplicity of just sticking them on. It'll also make them easier to replace if something goes wrong. I guess it's a trade off, and as the designer you get to make that choice and I will support it!

 

[JTarmstr]

As Chuppster said, if you keep it light - don't do extra fillets of glue everywhere, keep the "smearing" of glue to a minimum, use a smaller battery - it should be fine. You don't HAVE to have a 5000mAh 4S and a 12-blade EDF to fly this bird, that's just what I have a lot of.

Ok, thanks, I might try building a light one, but I like my planes fast and strong so I will probably just get a twelve blade EDF and enjoy this beautiful airplane.

 

[kilroy07]

I bought 3 of the EDFs you recommended that were on sale, could they power this?

I bought a couple (4) too, and while mine are destined for a different project, here's what my "opinion" is (take it for what it's worth.)

A link to the EDF I used is above doing some math, my setup was around 750-760 Watts of power.
My Viper literally leapt out of my hands on the maiden (Sorry, I didn't record the build weight before she went a shucking. But my second is all cut out and waiting some attention!)
It flew very nice on that set up (but only for about 5 minutes) even at half throttle (as Chuppster mentioned.)

So, I think it might fly on the 69mm edfs, but you'll probably have to be close to max throttle (at least 75% I think...) and that's probably going to eat up your battery pretty quickly.

So... this discussion leaves me with two options I think...
Bench test the EDFs (they are sitting next to me as I type this, but I would have to fabricate some sort of test stand) and see just how much thrust they are really putting out OR, maybe start looking for a different motor to bump them up.

So, not a definitive answer either way. So, build TWO!!...

 

[JTarmstr]

I bought a couple (4) too, and while mine are destined for a different project, here's what my "opinion" is (take it for what it's worth.)

A link to the EDF I used is above doing some math, my setup was around 750-760 Watts of power.
My Viper literally leapt out of my hands on the maiden (Sorry, I didn't record the build weight before she went a shucking. But my second is all cut out and waiting some attention!)
It flew very nice on that set up (but only for about 5 minutes) even at half throttle (as Chuppster mentioned.)

So, I think it might fly on the 69mm edfs, but you'll probably have to be close to max throttle (at least 75% I think...) and that's probably going to eat up your battery pretty quickly.

So... this discussion leaves me with two options I think...
Bench test the EDFs (they are sitting next to me as I type this, but I would have to fabricate some sort of test stand) and see just how much thrust they are really putting out OR, maybe start looking for a different motor to bump them up.

So, not a definitive answer either way. So, build TWO!!...

Great advice, I ahve already put $20 dollars of foam into my 2019 design challenge plane (I will be updating that soon with the EDF photos and prototype 1) so it would be great to put a ton of foam into that, xD. I might build two but I have so many projects and I cant build them all at once, this will probably be built in December or January anyway once I have finished my spaceplane and the Ft Edge 540 I am going to start soon.

 

[jagee]

Here's my finished bird ready to maiden.

I got tired of painting so decided I'd be done even though it isn't perfect. I scaled the plans to 90% when I printed them so that it would work with my 64mm EDF that i have on hand.

Hopefully I can get some good video of my maiden and I'll share it here.

Thanks to Ben for a very rewarding design!

 

[Mid7night]

That looks awesome! Can't wait to see it in the air!

 

[IcedStorm777]

@Mid7night.

Im new to EDF's but have a good amount of experience with other RC planes. I have a few questions about your F-16. First off it is an amazing model and i want to congratulate you on its success. Do the plans you posted work for Laser cutter plans? I've scratch built one rc plane but hand cut all the peices. did you laser cut your parts or were they hand cut? I don't own a laser cutter but my local library has a makerspace with one so i think i could use that. Is this an easy to fly\ build EDF? as i said i have experience flying but never an EDF. Thank you for your time!

 

[IcedStorm777]

Also, im putting a turnigy 2226-3000kv brushless outrunner into a 70mm 12 blade fan unit. do you think that will be enough power? I have a 3s 3200mah battery. do you think i would need a bigger battery and if so what would you reccommend?

The outrunner:
https://hobbyking.com/en_us/turnigy-2226-3000-70mm-edf-outrunner.html

The EDF unit:
https://hobbyking.com/en_us/blade-high-performance-70mm-edf-12-blades-ducted-fan-unit.html

The battery:
https://www.horizonhobby.com/3200mah-3s-111v-30c-lipo-battery--12awg--ec3-p-kxsb0017

Sorry, i'm a bit clueless about EDF's

 

[kilroy07]

I don't own a laser cutter but my local library has a makerspace with one so i think i could use that.

What is the working area of the laser (dimensions of the maximum cut area possible)?

The reason I ask is mine has a working area of 700x500mm and I shared my cut files (modified from Ben's) back on Aug 7th (search back on page 5 of this forum.) I shared them as a DXF, their laser software should be able to pull those right in.

It really flies great! There are a couple videos posted here attesting to that (including my own.)

 

[IcedStorm777]

What is the working area of the laser (dimensions of the maximum cut area possible)?

The reason I ask is mine has a working area of 700x500mm and I shared my cut files (modified from Ben's) back on Aug 7th (search back on page 5 of this forum.) I shared them as a DXF, their laser software should be able to pull those right in.

It really flies great! There are a couple videos posted here attesting to that (including my own.)

Thank you i will figure out what it is. dont know right now though.

 

[Chuppster]

@Mid7night.

Is this an easy to fly\ build EDF? as i said i have experience flying but never an EDF. Thank you for your time!

I would say it's not very easy to build, but that's why we are here, to help! It is, however, the easiest to fly EDF I own (I have 3, see my signature).

 

[IcedStorm777]

I would say it's not very easy to build, but that's why we are here, to help! It is, however, the easiest to fly EDF I own (I have 3, see my signature).

I really appreciate the support!

 

[IcedStorm777]

What is the working area of the laser (dimensions of the maximum cut area possible)?

The reason I ask is mine has a working area of 700x500mm and I shared my cut files (modified from Ben's) back on Aug 7th (search back on page 5 of this forum.) I shared them as a DXF, their laser software should be able to pull those right in.

It really flies great! There are a couple videos posted here attesting to that (including my own.)

There are two libraries that have makerspaces. One has the Epilog Zing 16 laser cutter. The other has the Epilog Helix 75 Watt Laser Engraver/Cutter. Which would work better for building the F-16? Are they even sufficient? I apologize for my ignorance as i know literally nothing about laser cutters\ laser cutting foam. I also would like to use the field of laser cutting for lots of different things so would like to learn about it. Also, if the laser cutter was used to cut the foam how would it cut some of the "lines" not all the way through (for curves in the fuselage) is that manual? Thank you for your time!!!

 

[Chuppster]

There are two libraries that have makerspaces. One has the Epilog Zing 16 laser cutter. The other has the Epilog Helix 75 Watt Laser Engraver/Cutter. Which would work better for building the F-16? Are they even sufficient? I apologize for my ignorance as i know literally nothing about laser cutters\ laser cutting foam. I also would like to use the field of laser cutting for lots of different things so would like to learn about it. Also, if the laser cutter was used to cut the foam how would it cut some of the "lines" not all the way through (for curves in the fuselage) is that manual? Thank you for your time!!!

I'm no expert, but if I understand correctly you have to fine tune the power setting on the laser so that you only cut part way through the foam. I would do this by running a calibration cut, possibly a few straight lines increasing the strength of the laser by 10%. Then once the cutting is done you can find the line that cuts part way through but not all the way through and go with that.

I'm pretty sure 75 watts is plenty for cutting foamboard, but the Helix is smaller than a sheet of foamboard, so you may have to cut half-sheets. The Zing is even smaller than the helix. A sheet of foam is 20" x 30."

 

[kilroy07]

The helix will be your best choice.
Looks like it has a 24x18" working area (approximately 610x460mm) so, you are probably going to have to make your own cut files.
Your going to have to become comfortable with a CAD program of some sort to take the "pieces" and rearrange to fit the Helix's working area.

"Cutting" verses "Etching" on lasers is a function of power/speed. I cut my foam in two passes to help minimize the cut back because the heat of the laser will melt the foam a bit and it will form a cupped area at the cut line. You are just going to have to play with those numbers until you find ones that work (or maybe someone here has experience with Epilog equipment.)

There's at least one other thread talking about laser cutters, so I don't want to hijack this one any more.