2026 Speed Challenge - Telnar1236

[telnar1236]

Now that you found a increase for the tail cone, I am going to suggest you look at putting at least 4 stator vanes for a better increase of least 6-10% thrust gain. This allows the flow to changing rotational into linear axial flow for better thrust. You should use a NACA 006 airfoil(taper trailing edge to a point) and stay between 5 to 10 degrees for incidence angle. Over ten degrees will reduce top speed.

So here is tail cone with the built into 4 stator vanes that gave the 6 bladed EDF plenty of power

View attachment 258205

In design, one other factor that I played with is reducing the tip gap between the blades and outer wall. I used Scotch magic tape (2 layers of tape .010-.015) and it increases the internal pressure of the duct as well as reducing spillage back into the entrance of the EDF so the thrust increases 4-6% more.
Imagined 3d printing a thin ring and putting that in between the blades and housing. Remember that the blades lengthen when spinning, so leave some small gap(less than 1 % of the blade tip chord) otherwise you will loose 3% thrust due to interaction between rotor tip and duct wall.

View attachment 258206

The EDF I'm using already has the stator vanes built in so fortunately no real need to add them in myself. Out of curiosity, what's your thinking behind using the NACA 0006 airfoil instead of a cambered airfoil?

Think I'm a bit too scared of the tape getting tangled up in my expensive 80mm 6s unit to try that trick on this plane, but I do need to try it sometime - 4-6% more thrust is always welcome

 

[L Edge]

The EDF I'm using already has the stator vanes built in so fortunately no real need to add them in myself. Out of curiosity, what's your thinking behind using the NACA 0006 airfoil instead of a cambered airfoil?

Think I'm a bit too scared of the tape getting tangled up in my expensive 80mm 6s unit to try that trick on this plane, but I do need to try it sometime - 4-6% more thrust is always welcome

It offers minimal profile blockage within the fan housing and delivers identical fluid turning performance for both the positive and negative flow angles of the stator vane. If you notice very few fly the F-117, same problem, need to change rotational to linear within the exit ducting to provide enough thrust.

As far as tape and doing damage to the blades, never happened. Closest was where I put 3 layers of tape and held the outer housing in my hand and applied full power(dumb, for I squeezed the housing and nicked the tape by a blade). As long as you clean the fan housing with alcohol and lay it straight(use only scotch magic tape), it will stay for years and very tough to get off as you can see above EDF.

Dyson has just designed a high speed EDF vacuum that fits in a handle(1.5" dia) and uses little power for his suction. If it was cheap and available, would love to explore that and see it in a 3d print plane what thrust it would get. Take a look at that. He is the king of designing vacuums.

Crappy weather, will fly that plane when it changes.

 

[telnar1236]

It offers minimal profile blockage within the fan housing and delivers identical fluid turning performance for both the positive and negative flow angles of the stator vane. If you notice very few fly the F-117, same problem, need to change rotational to linear within the exit ducting to provide enough thrust.

As far as tape and doing damage to the blades, never happened. Closest was where I put 3 layers of tape and held the outer housing in my hand and applied full power(dumb, for I squeezed the housing and nicked the tape by a blade). As long as you clean the fan housing with alcohol and lay it straight(use only scotch magic tape), it will stay for years and very tough to get off as you can see above EDF.

Dyson has just designed a high speed EDF vacuum that fits in a handle(1.5" dia) and uses little power for his suction. If it was cheap and available, would love to explore that and see it in a 3d print plane what thrust it would get. Take a look at that. He is the king of designing vacuums.

Crappy weather, will fly that plane when it changes.

Based on what I've seen from production EDFs even 6% thickness on the stators might be too thick. I think a cambered airfoil also gets better efficiency since the EDF only turns in one direction and therefore the AOA of the airfoil can be set to always be positive. But for these planes, I think I'm going to stick with the stock EDFs I've been designing around - the rest of the design is experimental enough for now.

 

[telnar1236]

Finally got the most complicated fuselage section designed

It contains the internal flap linkages, the ESC, and of course the ducting.

The ESC is cooled by air diverted from the inlet duct through a NACA inlet. It then goes into a sealed duct containing the ESC from which it will be returned to through the wire fairing to the tail cone for motor cooling and eventually will go back into the flow through the thrust tube (the return duct isn't modeled yet since it's part of the EDF housing). This is a much more refined version of the system I used in my sport jet and the Ghost. While it is probably a bit less efficient than pulling air from outside the plane, it does look better which as we all know is what really matters.

The ESC is held away from the duct by a bunch of channels so it should get good airflow on all sides just in case I decide to do something stupid with upping the current draw or going to 8s later on.

 

[telnar1236]

And finally, finally, after months of trying to get it working reliably, here's some video of the Ghost. And I beat its previous top speed and took it up to 127 mph today (not an official speed for the contest since the Ghost predates it - although I might have rebuilt enough of it for it to count as a whole new plane in the past month and half 😭).

The landing wasn't the greatest because I wasn't at the top of my game and it was a bit gusty, but all 3 struts remained on the plane and there was no damage so I think I can finally call the gear a success.

With the Ghost working reliably(ish) now it's pretty much done with its job as a testbed. The only remaining thing I want to try is fitting a tail cone to the 70mm EDF motor just to make sure it doesn't do something unexpected but the worst issue that is likely to result is the tail cone getting blown out the back of the plane. While it will remain on the backburner for now, same as my other non-speed projects, I do eventually intend to release the STLs for this one and put together a manual. I also designed the wing with hardpoints with the goal of being able to carry various payloads aloft and up to relatively high speeds (think lifting bodies and test gliders for future projects) so the Ghost will likely remain a fixture and enable many designs to come. In terms of what I need to do to prepare it for release, the nose fuselage section is both weak and heavy since I never changed it from the original vase mode design, so I need to redesign that, and with how fast it already is, I may decide to add some kind of gear doors to cut drag still further.

 

[LitterBug]

And finally, finally, after months of trying to get it working reliably, here's some video of the Ghost. And I beat its previous top speed and took it up to 127 mph today (not an official speed for the contest since the Ghost predates it - although I might have rebuilt enough of it for it to count as a whole new plane in the past month and half 😭).

View attachment 258247

The landing wasn't the greatest because I wasn't at the top of my game and it was a bit gusty, but all 3 struts remained on the plane and there was no damage so I think I can finally call the gear a success.

With the Ghost working reliably(ish) now it's pretty much done with its job as a testbed. The only remaining thing I want to try is fitting a tail cone to the 70mm EDF motor just to make sure it doesn't do something unexpected but the worst issue that is likely to result is the tail cone getting blown out the back of the plane. While it will remain on the backburner for now, same as my other non-speed projects, I do eventually intend to release the STLs for this one and put together a manual. I also designed the wing with hardpoints with the goal of being able to carry various payloads aloft and up to relatively high speeds (think lifting bodies and test gliders for future projects) so the Ghost will likely remain a fixture and enable many designs to come. In terms of what I need to do to prepare it for release, the nose fuselage section is both weak and heavy since I never changed it from the original vase mode design, so I need to redesign that, and with how fast it already is, I may decide to add some kind of gear doors to cut drag still further.

NICE!!

 

[bisco]

wow! tearing up the sky!

 

[telnar1236]

wow! tearing up the sky!

Just wait for the Super Duper Sabre - it has 60% of the drag with almost 30% more thrust. Based on the Ghost and scaling by those numbers we're looking at a 170-185 mph top speed, although there remain a lot of possible confounding factors

 

[Houndpup Rc]

And finally, finally, after months of trying to get it working reliably, here's some video of the Ghost. And I beat its previous top speed and took it up to 127 mph today (not an official speed for the contest since the Ghost predates it - although I might have rebuilt enough of it for it to count as a whole new plane in the past month and half 😭).

View attachment 258247

The landing wasn't the greatest because I wasn't at the top of my game and it was a bit gusty, but all 3 struts remained on the plane and there was no damage so I think I can finally call the gear a success.

With the Ghost working reliably(ish) now it's pretty much done with its job as a testbed. The only remaining thing I want to try is fitting a tail cone to the 70mm EDF motor just to make sure it doesn't do something unexpected but the worst issue that is likely to result is the tail cone getting blown out the back of the plane. While it will remain on the backburner for now, same as my other non-speed projects, I do eventually intend to release the STLs for this one and put together a manual. I also designed the wing with hardpoints with the goal of being able to carry various payloads aloft and up to relatively high speeds (think lifting bodies and test gliders for future projects) so the Ghost will likely remain a fixture and enable many designs to come. In terms of what I need to do to prepare it for release, the nose fuselage section is both weak and heavy since I never changed it from the original vase mode design, so I need to redesign that, and with how fast it already is, I may decide to add some kind of gear doors to cut drag still further.

Just wait for the Super Duper Sabre - it has 60% of the drag with almost 30% more thrust. Based on the Ghost and scaling by those numbers we're looking at a 170-185 mph top speed, although there remain a lot of possible confounding factors

Wow, nice!! Your designing skills are amazing!👍

 

[telnar1236]

Wow, nice!! Your designing skills are amazing!👍

Thanks, real test will be if the Super Duper Sabre can manage to not turn into confetti at those speeds

 

[Houndpup Rc]

Thanks, real test will be if the Super Duper Sabre can manage to not turn into confetti at those speeds

😂😂👍

 

[telnar1236]

Got more of the fuselage and the tail surfaces printed. The only remaining large pieces are the last section of the tail fuselage and the canopy.

It's looking like the 2500g predicted flying weight will be pretty much spot on. It ended up being so hard to get the first half of the tail fuselage in place that I broke the nose by accident, so I needed to reprint that too. I also redesigned the access panels for the flap servos to make it easier to access them so now they're right where they need to be.

Finally, I decided to make the vertical stabilizer removable. Originally, it was intended to be glued in place for simplicity and to reduce weight a bit but thinking about how I want to conduct the maiden flight, I'll probably end up flying it in primer, so I don't paint the whole thing only to have it crash. This means the plane will be mostly gray, so I think I'll probably print a tail in red filament to use solely until I get the thing fully ready to go.

 

[telnar1236]

Unfortunately, I don't think I have time to complete both the Super Duper Sabre and the Demon for this competition, so it'll just be the Super Duper Sabre for the moment. The Demon also feels a bit out of the spirit of this contest - an 8s or 12s jet that requires its own specialized hardware to be able to takeoff and can really only be safely flown at a dedicated flying field will be a fun project at some point, but it's also not really in keeping with the other foam board and 3D printed designs being entered.

I may end up doing a smaller simpler 64mm EDF instead if I have time. It won't win, but it would be cool to have a 140mph plane that uses cheaper and more easily accessible parts, plus with a 6s setup, it might even be somewhat competitive. Plus, my BLI inlet designs have yet to really have had a chance to shine.

 

[Houndpup Rc]

Got more of the fuselage and the tail surfaces printed. The only remaining large pieces are the last section of the tail fuselage and the canopy.

View attachment 258300

It's looking like the 2500g predicted flying weight will be pretty much spot on. It ended up being so hard to get the first half of the tail fuselage in place that I broke the nose by accident, so I needed to reprint that too. I also redesigned the access panels for the flap servos to make it easier to access them so now they're right where they need to be.

View attachment 258301

Finally, I decided to make the vertical stabilizer removable. Originally, it was intended to be glued in place for simplicity and to reduce weight a bit but thinking about how I want to conduct the maiden flight, I'll probably end up flying it in primer, so I don't paint the whole thing only to have it crash. This means the plane will be mostly gray, so I think I'll probably print a tail in red filament to use solely until I get the thing fully ready to go.

Looking good! BTW, where do you get your filament? (Mainly LW pla)

 

[Houndpup Rc]

Unfortunately, I don't think I have time to complete both the Super Duper Sabre and the Demon for this competition, so it'll just be the Super Duper Sabre for the moment. The Demon also feels a bit out of the spirit of this contest - an 8s or 12s jet that requires its own specialized hardware to be able to takeoff and can really only be safely flown at a dedicated flying field will be a fun project at some point, but it's also not really in keeping with the other foam board and 3D printed designs being entered.

I may end up doing a smaller simpler 64mm EDF instead if I have time. It won't win, but it would be cool to have a 140mph plane that uses cheaper and more easily accessible parts, plus with a 6s setup, it might even be somewhat competitive. Plus, my BLI inlet designs have yet to really have had a chance to shine.
View attachment 258302

Looks a lot like the kingfisher mach initiative is making!

 

[telnar1236]

Looking good! BTW, where do you get your filament? (Mainly LW pla)

Amazon mostly - either the Esun or Sainsmart stuff when it goes on sale - normally it's about $50 per kilo which is fairly typical for LW-PLA but too expensive in my opinion but every so often it goes on sale for $25-$30 per kilo which is much more reasonable. I actually prefer the way these brands print to the colorFabb stuff too - I think they foam up a bit more so they're less precise but they feel tougher

 

[Houndpup Rc]

Amazon mostly - either the Esun or Sainsmart stuff when it goes on sale - normally it's about $50 per kilo which is fairly typical for LW-PLA but too expensive in my opinion but every so often it goes on sale for $25-$30 per kilo which is much more reasonable. I actually prefer the way these brands print to the colorFabb stuff too - I think they foam up a bit more so they're less precise but they feel tougher

Thanks!👍

 

[telnar1236]

Looking good! BTW, where do you get your filament? (Mainly LW pla)

But I don't use all that much LW-PLA - even accounting for the foaming ABS is cheaper once you take into account that you need less structure with it and it isn't that much heavier either and there's no post-processing required

 

[Houndpup Rc]

But I don't use all that much LW-PLA - even accounting for the foaming ABS is cheaper once you take into account that you need less structure with it and it isn't that much heavier either and there's no post-processing required

How hard is it to print with?

 

[telnar1236]

How hard is it to print with?

If you have an enclosure, it's really not that bad at all - you need glue stick on the bed and you need to set the bed temp as close to 100 as your printer can get, and without an enclosure it warps and comes unstuck from the bed like crazy, but if you have even a cardboard box to put your printer in and keep everything sealed up, it's pretty easy to deal with. If you use CF-ABS you pay about $5-10 extra per kilo but you get rid of the warping almost completely - however you do have to be super careful with post processing any CF filament since the fibers are pretty nasty and you really don't want to breathe them in if you sand it, and you need a hardened steel nozzle, but for whatever reason, I think ABS prints better with a steel nozzle in general