Looking for Ideas for 3D Printed Jets

[L Edge]

So your looking for a 2 EDF 50 mm plane. Coming from across the big pond I offer you the Gloster Meteor from UK. An excellent candidate.

First thing you should notice is the large wing area, diheadral, t-tail and with 3d printing, should present short take offs and slower landings. This plane is for someone who has some jet experience so that it doesn't need gear and could easily flare in over grass. If you use Differential Thrust, it removes one servo for less weight. Put gear on it, practice getting out of those bumpty bumps landings, that ends up damaging most jets. This is where you become a jet jockey.

Besides studying the flow patterns, I look at it from a force and moment approach and if you also design each the EDF pod so the inlet and outlet is printed, just insert the EDF so no steps, bends, etc, so losses will be minimized.

PS: If you want a jump ahead of others, suggest you start looking into small metal EDF's(well balanced) that turn much faster. Our plastic blades suck in bending, torsion and leakage. One thing that designers overlook is big gaps between fan blades and housing. That metal one will take care of that. I had 5 bladed 64mm and the gap is terrible. Since the static pressure is bigger inside, it will leak thru that front gap and even disturb the incoming airflow.. I use to put 2 layers of magic tape on the fan blade housing. By hovering before/after, tape was placed I hovered at 52% throttle. After tape added, it hovered at 47%, so it gain thrust, how much? Try it on one of your fans. Yes I do look at airflows, not your way.

 

[telnar1236]

So your looking for a 2 EDF 50 mm plane. Coming from across the big pond I offer you the Gloster Meteor from UK. An excellent candidate.

View attachment 254059


View attachment 254060

First thing you should notice is the large wing area, diheadral, t-tail and with 3d printing, should present short take offs and slower landings. This plane is for someone who has some jet experience so that it doesn't need gear and could easily flare in over grass. If you use Differential Thrust, it removes one servo for less weight. Put gear on it, practice getting out of those bumpty bumps landings, that ends up damaging most jets. This is where you become a jet jockey.

Besides studying the flow patterns, I look at it from a force and moment approach and if you also design each the EDF pod so the inlet and outlet is printed, just insert the EDF so no steps, bends, etc, so losses will be minimized.

PS: If you want a jump ahead of others, suggest you start looking into small metal EDF's(well balanced) that turn much faster. Our plastic blades suck in bending, torsion and leakage. One thing that designers overlook is big gaps between fan blades and housing. That metal one will take care of that. I had 5 bladed 64mm and the gap is terrible. Since the static pressure is bigger inside, it will leak thru that front gap and even disturb the incoming airflow.. I use to put 2 layers of magic tape on the fan blade housing. By hovering before/after, tape was placed I hovered at 52% throttle. After tape added, it hovered at 47%, so it gain thrust, how much? Try it on one of your fans. Yes I do look at airflows, not your way.

Not a bad idea - like you said, it should be a good intro to jets

 

[telnar1236]

Think I'm actually going to change my priorities around and build something from this list even before my 80mm Super Duper Sabre. With all the TFRs on weekends, I'll never get to fly unless I have something that I can chuck in the back of my car to get in the air after work and my mini trainer jet and Saab 105 are both a bit too tame. That probably means the 64mm sport jet or maybe something with the 70mm fan designed with a bit more of a focus on performance.

 

[L Edge]

Might be a bit too complex for this set of projects - knowing myself I'd want to make it truly tailless instead of using a transparent vertical stabilizer and get way too sucked into the aerodynamics and spend as much time on that design as I expect to on the super duper sabre design. I do want to build something tailless sometime down the road though, so I'll never say never

Your right, never say never.

Here's another idea :

Solved the no tail vertical stab by re-inventing the aileron/rudder mix in a transmitter. I used a thrust vectoring nozzle rotated 45 degrees off axis. I used 2 servos (outer hole) was used for elevons where wires(by star) go to each control.

Here's the kicker, with TVN rotated off 45 degrees from perpendicular (see white area on the nozzle) wire that is hooked to middle hole in servo. This allows aileron movement and rudder movement together. So you made a turn with the elevons, so as roll was added, it add's the invisible mix for (rudder) yaw to complete the turn. So the roll/yaw problem is solved. Took awhile to get correct ratio (servo arm, distance between each hole) and different servos so plane didn't skew in turn. Hate gyros, I want to fly the plane.
Try it with a printed TV nozzle. Have a video to show complete flight.

Idea 2:

You wanted long flights with a EDF.. I chose the flying wing and it took me time to figure that one. So needed to get rid of the vertical drag component and improve boundary layer(checked with tufts). Incorporated my "stabilizer" and I now have a very stable flying wing that flies for over 10 minutes. Took awhile to tune it. It takes a long time for it to slow down. Very slippery. That's how I solved the longer flight position. Again, video to show complete flight.

How about vortex approach?

 

[Piotrsko]

Need a.kit? I suggest a junior nobler for control line.

 

[telnar1236]

Your right, never say never.

Here's another idea :
View attachment 254090

Solved the no tail vertical stab by re-inventing the aileron/rudder mix in a transmitter. I used a thrust vectoring nozzle rotated 45 degrees off axis. I used 2 servos (outer hole) was used for elevons where wires(by star) go to each control.

Here's the kicker, with TVN rotated off 45 degrees from perpendicular (see white area on the nozzle) wire that is hooked to middle hole in servo. This allows aileron movement and rudder movement together. So you made a turn with the elevons, so as roll was added, it add's the invisible mix for (rudder) yaw to complete the turn. So the roll/yaw problem is solved. Took awhile to get correct ratio (servo arm, distance between each hole) and different servos so plane didn't skew in turn. Hate gyros, I want to fly the plane.
Try it with a printed TV nozzle. Have a video to show complete flight.

Idea 2:

You wanted long flights with a EDF.. I chose the flying wing and it took me time to figure that one. So needed to get rid of the vertical drag component and improve boundary layer(checked with tufts). Incorporated my "stabilizer" and I now have a very stable flying wing that flies for over 10 minutes. Took awhile to tune it. It takes a long time for it to slow down. Very slippery. That's how I solved the longer flight position. Again, video to show complete flight.

View attachment 254095

How about vortex approach?

It's impressive that you've gotten a foam board wing to fly tailless. I think a tailless design is a bit too complex and likely to be difficult for this set of projects though.

 

[telnar1236]

For the 64mm sport jet, I think this will be my design. It's not quite a viper, but it's certainly viper adjacent.

I'm using the same laminar flow airfoil as on my main speed jet project, and taking some of the lessons from the inlet design in that project, the inlets for this jet should hopefully be much more efficient and lose less thrust despite being calibrated to be only a bit over 100% FSA.

It has a 34.6" wingspan and a 35.4" length, so it should be pretty lightly loaded, but top speed should still be pretty good. If I have not improved inlet efficiency at all over the 50mm super duper sabre, then top speed should be about 87 mph, but with improvements to the efficiency, top speed might be as high as 108 mph. Having the combination of thrust testing, CFD, and a measured top speed has allowed me to refine my calculations a fair bit, so the big question is if the inlet improvements do what I think they will.

It will be built out of LW-PLA since that proved to be extremely tough in a hand launch design in my 50mm super duper sabre and since building using those techniques lets me construct the plane over the course of a few days instead of a month or more. I did not include the ventral fins the viper typically has since my experience with similar fins on the super duper sabre was that they elevate the nose and lead to it digging in when belly landing.

 

[L Edge]

You use diagrams, videos, etc. My wind tunnel is the flight to see my results for the idea.

How about a X-29 3d plane you can use to learn how to fly EDF's? No need to worry about bend and torsion.

Very simple, the inward flow over the wing and slower speeds is an excellent trainer for launch/runway as well as chucking it and landing it on grass or runway. I even played the game of starting a landing turn, go into a stall, drop and recover and finish off landing(no damage). That's what you need for a trainer.

Exploring the FSW(forward swept wing) started like this:
Look Ma, no fixed canard!!!!!!! Left it off to see what happens. Notice I picked a design(inside the plane with airflow hoping the inward flow helps distribution) to the protect EDF from crashes and debris. A simple 2 piece setup with good thrust.

Need I say anything. Now let's add a canard.

I use a 5 bladed 64mm EDF, and see what it does when I go into high alpha, even on chucking it, no roll over and snap to the ground. Still have a pushed back CG and it works, ( 1:23) not crash compared to other trainers.
This flying is testing plane limits, feeling the stall coming especially in the turns. It is like a SIG Cadet.
A EDF pilot need to be able to put the jet where he wants, slow it down, nail the descent and turn to final and land where he control the landing spot. A slippery fast moving jet landing is the common error of crashes and bumpty bumps.

Here is another one video showing the range of fairly fast to the game of sharp turn, put into stall and out where I was going to land if high enough. Close, but no cigar. So, point is made that the X-29(this shape or regular design 3D print) could be used as a good trainer.

So why doesn't someone slam together a X-29 and learn how to fly and land an EDF?

Taking it to the limit, it worked. I took a F-22 TomCat and took the swept back wing (45 degrees) and combined it with the swept forward wing (-33 degrees) and 9 months of design and testing have a flyable plane that morphs in flight.

Plane takes off wings perpendicular, can fold back to 45 degrees, go back to perp, and then move the wing forward -33 degrees in flight. Have 2 videos, but will show one show how slow it can go in forward flight with great stability.
That is a show stopper when I bring it to the club. Have to unload G"s doing in an an arc so servo don't strip. Even NASA doesn't have one of these. Once in awhile, I do a landing with the wing forward.

X-29 is a plane that's unique and a good candidate for any EDF.

 

[telnar1236]

I think I've pretty much got my list of designs now. The prototype of the Super Duper Sabre doesn't have enough roll authority without ailerons, so I don't really feel good about giving it to someone else once I'm done with it, so I'm going to recycle the EDF along with the other 4s Powerfun unit into a meteor, then the other 50mm unit will go into a MiG 15 since I think that kind of design will work well with its low thrust and very flat thrust curve. And finally I'm going to build a plane from my modular plane system around the 70mm EDF, since I have most of an airframe from that system that I haven't been doing anything with and that I also need to get rid of.

 

[telnar1236]

Some more progress on the 64mm sport jet design. I'm hoping it will take less than a week to build which will set the pace for me to get all of these built and donated in a reasonable timeframe. The nose fuselage is already printed.

I'm also experimenting with modular connections using PLA inserts in an LW-PLA airframe to make it easier to replace individual parts. The insert should give the surrounding material the strength to hold onto screws while the LW-PLA should keep things nice and light.

 

[Piotrsko]

I have seen your current design somewhere before. Mind is screaming the name viper but with less ducting intakes

This being old isn't for the faint, maybe that's why you ease into it.

 

[FlyerInStyle]

@telnar1236 have you ever tried a bdf? or a VTOL?

 

[telnar1236]

I have seen your current design somewhere before. Mind is screaming the name viper but with less ducting intakes

This being old isn't for the faint, maybe that's why you ease into it.

Yeah, it's pretty much a viper. I figured why reinvent the wheel when there's already such a good design for a sport jet out there

 

[telnar1236]

@telnar1236 have you ever tried a bdf? or a VTOL?

Not really - BDFs are sort of an awkward middle ground between a ducted fan and a prop for me - they're pretty good but I personally prefer higher blade count designs despite them maybe being less efficient because they have a smaller diameter for the same thrust which makes them easier to fit into more designs. I think BDFs are probably very good for foam board though.

For VTOL, I've considered it, but most of the time I think it's easier to design for hand launching or to use a runway. The VTOL system is cool, but it's added complexity and weight, and I have ready access to a paved runway, so it doesn't really make sense for me.

 

[telnar1236]

Got most of the fuselage printed, although it still needs the tail cone.

The ducting efficiency seems to be pretty good so far and it produces quite a bit of thrust when I spool up the fan. Since the rest of the duct is the thrust tube, I think I'll probably keep that with the full duct as well, or maybe even get a bit more thrust. It also sounds really good. For some reason, this duct produces a really strong whoosh sound at lower to middle throttle settings and almost whistles at higher settings. I think it may be due to the cooling for the ESC which diverts some of the air around the fan through the ESCs compartment.

I know the sound represents lost thrust, but it doesn't seem to be losing too much and this design isn't really meant to be breaking any records, so I don't feel the need to change it.

 

[Houndpup Rc]

Not really - BDFs are sort of an awkward middle ground between a ducted fan and a prop for me - they're pretty good but I personally prefer higher blade count designs despite them maybe being less efficient because they have a smaller diameter for the same thrust which makes them easier to fit into more designs. I think BDFs are probably very good for foam board though.

For VTOL, I've considered it, but most of the time I think it's easier to design for hand launching or to use a runway. The VTOL system is cool, but it's added complexity and weight, and I have ready access to a paved runway, so it doesn't really make sense for me.

More blades means a better sound! (More like a turbine)

 

[telnar1236]

More blades means a better sound! (More like a turbine)

Can't say I'm complaining about the sound either

 

[telnar1236]

Got the rest of the fuselage, the tail, and part of one wing printed. CG seems to be in a good place and I'm liking the way it looks so far

 

[Houndpup Rc]

Got the rest of the fuselage, the tail, and part of one wing printed. CG seems to be in a good place and I'm liking the way it looks so far
View attachment 254211

Nice! I am starting on my first 3D printed plane too!

 

[Mr Man]

Nice! I am starting on my first 3D printed plane too!

I’m currently designing a 3d printer Ted plane. (Radjet/vortex)