Houndpup Rc
Legendary member
I have had pretty good luck with Creality Print and it has a more modern UI IMO👍
Experimental EDF Jets and Other Ideas
- Thread starter telnar1236
- Start date
Mr Man
Mr SPEED!
Alright, I'll stick with Cura then 👍 I also like its interface quite a bit!
L Edge
Legendary member
I got it built in my looking for ideas thread but between TFRs essentially every weekend and some real-life stuff I haven't had the chance to test fly yet
Today, I got to fly my modified plane (had prop, now 5 bladed 64mmEDF) to explore what effects with the boundary layer, if any mounted in the rear.
Plane acted totally different when flying then with a prop, and the other factor, the EDF seemed to accelerate faster which is different. It will be interesting to see what you think and what comments you make with your setup.
I noticed you are getting some good speed with some of your planes which means longer runways for landing. Been doing a lot of searching for info and noticed the guys flying dia of 80 -100 EDF's when they come in, really eat the runway quickly. But then, you can hear the EDF(s) spin up and do the braking for them. Quite a number of saves from damage I would say.
Maybe you should explore one of the working ESC's that reverses with the flip of a switch. Mine became uncomfortable when the reverse throttle went past 2/3 where I envision a reduced plastic blade life. Seems to be a life saver for the pilots especially when they come in high, hot and heavy..
telnar1236
Master member
Any video of the plane flying in this configuration?
I still need to test my BLI wing - I've built up quite the backlog of planes to test fly between the TFRs and some other craziness around here. But now that we're more into summer, I'm getting to fly more again and working through it (though not that quickly - I tend to only bring one or at most two new airframes to test to the flying field at a time since I still want space to bring something proven that I can fly if the new design crashes). And I've been prioritizing my laminar flow wing designs for the speed competition more than the other designs lately.
L Edge
Legendary member
Will do in awhile.
I'm busy right now with my VTOL where I'm finally solved my problem and doing a lot of testing (flying at hover) to hopefully have a full transitional flight without damage or crashing.
Wish I was a lot younger for the future of designing RC EDF planes will be in CAD systems and 3D printing. Ever since FFF and depron left the market, selection is very poor. Wait until you try dual EDF's with crazy shape stealth exits and no rudders. Loss of thrust plus other issues will have to be overcome.
TreadHead98
Member
@telnar1236, How's the f-100ish coming?
telnar1236
Master member
Got the 70mm testbed flying and have been working on dealing with issues with the common landing gear. I've also finally started building the Super Duper Sabre as part of the speed competition this year in this thread
2026 Speed Challenge - Telnar1236
This is my thread for the 2026 speed challenge. I'll likely be building two planes for it, the Super Duper Sabre design I've been working on optimizing in the background for some time and an as yet nameless design which is intended to run a 90mm fan on 8s, or maybe even 12s. First is the Super...
forum.flitetest.com
telnar1236
Master member
Something I looked into a bit earlier in this project but never resolved to my satisfaction was if it's worth it to fair in the control horns for the ailerons. Conclusions are as follows:
By contrast a well-designed fairing has less pressure on the leading edge and good pressure recovery on the trailing edge, but it's bigger and therefore has more skin friction drag and a larger frontal area. The drag is less but it's a reduction from 0.08 N to 0.06 N (8g to 6g) at 110 mph so it's not a huge impact on the plane one way or the other. One advantage I didn't look at is it also closes the gap into the servo bay, so it's probably a somewhat larger improvement than accounted for here, but even doubled or tripled, that's less than 1% of the thrust from the 80mm EDF.
And an open backed fairing is the worst of both worlds with a large frontal area, high surface area, and poor pressure recovery.
- It isn't really a huge difference one way or another. The difference between the bare linkage and an optimized fairing is about 1mph assuming a 160 mph top speed for the Super Duper Sabre and will probably be less significant for most designs as they are higher drag with more power to compensate
- An open backed fairing is worse than the bare linkage (you see these on most production speed planes and it seems like they're probably shooting themselves in the foot a tiny bit)
- A close backed fairing with a good profile is about 75% the drag of the bare linkage and is therefore somewhat an improvement
By contrast a well-designed fairing has less pressure on the leading edge and good pressure recovery on the trailing edge, but it's bigger and therefore has more skin friction drag and a larger frontal area. The drag is less but it's a reduction from 0.08 N to 0.06 N (8g to 6g) at 110 mph so it's not a huge impact on the plane one way or the other. One advantage I didn't look at is it also closes the gap into the servo bay, so it's probably a somewhat larger improvement than accounted for here, but even doubled or tripled, that's less than 1% of the thrust from the 80mm EDF.
And an open backed fairing is the worst of both worlds with a large frontal area, high surface area, and poor pressure recovery.
telnar1236
Master member
With its participation in the speed challenge wrapping up and a rebuild in progress, figured it was time to move the documentation of the Super Duper Sabre back to its original thread.
First off a summary of what happened. In its current form, the plane is a 150 mph design capable of five and a half minutes of time on throttle. However, it required quite a few changes to get where it is from what I last posted in this thread, more or less as follows
To fix the inverted stability issues, I have 2 things I want to change. First, I want to add wing fences on the bottom of the wing too since the current wing fences only work when the plane is upright. I also want to replace the carbon fiber bushings for the stabilators with actual bearings to eliminate the remaining play there which should make roll inputs feel much more precise. I doubt it will ever fly great inverted, but I'll settle for ok with how well everything else works.
The landing gear issue is probably just a matter of replacing the somewhat abused retract units.
And the final change is to the battery. I can fly 5:30 and come down with 20% left on a 5200 mAh pack, but the original goal was 7+ minutes. To achieve that, I need to put together the 9000 mAh Li-Ion pack I've been working on. That should let it hit the 7 minute mark wit room to spare.
First off a summary of what happened. In its current form, the plane is a 150 mph design capable of five and a half minutes of time on throttle. However, it required quite a few changes to get where it is from what I last posted in this thread, more or less as follows
- Landing gear problems resolved by change to a fully CF strut with scissor link for all gear
And structural problems on landing around all landing gear mounts resolved by adding 2 additional carbon fiber spars going most of the span of the wing and 2 carbon fiber rods under the inlet duct to support the nose gear as well as some changes to the print settings on the wing to use a better infill option. This added a fair bit of weight
But it flew well in general - More landing gear changes to further reduce loads from the main gear on the wing - switched to trailing link design, more added weight
- Added weight hurt slow flight capability. Shifted CG aft to improve performance and reduce landing speed but this introduced some instability which made handling on landing difficult. Fixed this by adding small extensions to the wings with 3.5 degrees of washout and abrupt change to Clark Y airfoil to fight tip stalls and spanwise flow. Added wing fences. Added extensions to all tail surfaces.
This was a huge improvement to handling throughout the flight envelope and made safe landings much easier. - Duct imploded during attempted takeoff run. Fixed by adding carbon fiber rod along top of duct in weak section and paying extra attention to catching and fixing any 3D printing artifacts along the duct.
- Current state of the project: retracts are unreliable and the plane shows severe instability and wing rock if it gets at all slow inverted (totally stable upright though).
To fix the inverted stability issues, I have 2 things I want to change. First, I want to add wing fences on the bottom of the wing too since the current wing fences only work when the plane is upright. I also want to replace the carbon fiber bushings for the stabilators with actual bearings to eliminate the remaining play there which should make roll inputs feel much more precise. I doubt it will ever fly great inverted, but I'll settle for ok with how well everything else works.
The landing gear issue is probably just a matter of replacing the somewhat abused retract units.
And the final change is to the battery. I can fly 5:30 and come down with 20% left on a 5200 mAh pack, but the original goal was 7+ minutes. To achieve that, I need to put together the 9000 mAh Li-Ion pack I've been working on. That should let it hit the 7 minute mark wit room to spare.
telnar1236
Master member
When I last left this thread, I was also planning on working on a less capable but still very good 4s airplane that would use cheaper parts, simpler techniques, and be more widely accessible to build, and I still want to do that, but the form has changed a bit as has my goal with it.
In terms of the form, I no longer plan to use twin 50mm EDFs. They provide a ton of thrust in ideal conditions, but are extremely sensitive to inlet and nozzle geometry and there is no one ideal design to use for them at all speeds so I'd be losing out on performance somewhere. Instead I plan to use a single 70mm EDF which gives more thrust under real conditions even if its max thrust is lower, and which is much more efficient too. The picture on the left is the old design and the one on the right the new one (the C12).
I now have a 133 mph 4s design in the form of the Rapier 64 (an offshoot of the BLI flying wing design that was in my original post in this thread) so I feel less need to make it go as fast as possible. Instead, I want it to slow down more easily and be more versatile (and maybe even hand launch capable). To that end the wing now uses the same laminar flow airfoil at the root but a Clark Y airfoil at the tip which results in something hugely stall resistant that also retains much of the low drag performance of the wing with the full span laminar flow airfoil. With the 70mm fan and overall higher lift/lower weight design, top speed is down to "only" a bit over 100 mph (in practice the old C10 would probably have been about the same due to the limitations of the 50mm power system in such a large plane). However, stall speed is 17.5% slower and stall handling should be hugely improved.
I also simplified the control surface layout - the C12 now only has flaps and no ailerons with roll control coming from the stabilators. Hopefully, it should be possible to build this plane as anywhere from a 3-channel to a 6-channel design and possibly even with a 64mm fan due to the reduced size (it's around the same size as the Falcata and should be a bit lighter if built without retracts, though top end speed would suffer).
In terms of the form, I no longer plan to use twin 50mm EDFs. They provide a ton of thrust in ideal conditions, but are extremely sensitive to inlet and nozzle geometry and there is no one ideal design to use for them at all speeds so I'd be losing out on performance somewhere. Instead I plan to use a single 70mm EDF which gives more thrust under real conditions even if its max thrust is lower, and which is much more efficient too. The picture on the left is the old design and the one on the right the new one (the C12).
I now have a 133 mph 4s design in the form of the Rapier 64 (an offshoot of the BLI flying wing design that was in my original post in this thread) so I feel less need to make it go as fast as possible. Instead, I want it to slow down more easily and be more versatile (and maybe even hand launch capable). To that end the wing now uses the same laminar flow airfoil at the root but a Clark Y airfoil at the tip which results in something hugely stall resistant that also retains much of the low drag performance of the wing with the full span laminar flow airfoil. With the 70mm fan and overall higher lift/lower weight design, top speed is down to "only" a bit over 100 mph (in practice the old C10 would probably have been about the same due to the limitations of the 50mm power system in such a large plane). However, stall speed is 17.5% slower and stall handling should be hugely improved.
I also simplified the control surface layout - the C12 now only has flaps and no ailerons with roll control coming from the stabilators. Hopefully, it should be possible to build this plane as anywhere from a 3-channel to a 6-channel design and possibly even with a 64mm fan due to the reduced size (it's around the same size as the Falcata and should be a bit lighter if built without retracts, though top end speed would suffer).
TreadHead98
Member
My 64 is waiting... You think a 3300 will work?
telnar1236
Master member
I'll be honest, this is still a long way from being ready and the 64mm option isn't at all certain yet nor is a hand launch capability. A 3300 mAh 4s should be fine if - the Falcata uses 2200 mAh-3000 mAh packs and could balance on heavier
telnar1236
Master member
While I've been reprinting the Super Duper Sabre, I've continued to work on designing the smaller/simpler airframe. Outwardly, there isn't too much change, but it now has a lot more internal structure. This is meant as a more practical implementation of the laminar flow airfoil in an airplane that can do more and be a bit more reliable. The Ghost is quite stable when set up right, but is a bit too sensitive to the exact setup and CG and easily becomes to difficult to slow down with a nose heavy CG or develops very nasty stall characteristics with a too tail heavy CG and the Super Duper Sabre is ridiculously capable and is a lot less sensitive to CG and is overall more stable, but the edges of the flight envelope, especially inverted remain somewhat sketchy. And the sport jet is just a bit too small to carry very much more than it does. So the new design, which I'm calling the Chimaera for its wing with a transition from the laminar flow airfoil root to the Clark Y tip is intended to fix that.
I've also designed a few wingtip accessories. Wingtip rails give a place to mount either scale-like accessories or things like cameras or airspeed sensors. Dummy tip tanks are great at damping out roll and making the airplane more stable as well as increasing lift a bit. They were very effective at this on my similarly sized F-104.
There will also be a centerline pylon for payloads that need power or a connection to the airplane like gliders or additional avionics with telemetry, or a drop mechanism. I've been meaning to add this to a number of my recent designs, but the pure laminar flow airfoil wings have been a bit too sensitive to things like CG for adding a potentially un-aerodynamic payload that might hurt flight characteristics and shift the lift around a bit. The gear will be fairly tall to avoid any issues with ground clearance.
I'm also continuing to look at the power system and it looks like anything from a 64mm 4s EDF to a 70mm 6s EDF should work, either with retracts, fixed gear, or hand launching (with a gyro for assistance).
Some options won't work well together - for example a 4s 64mm EDF with retracts would be very underpowered and a 70mm 6s EDF would be quite heavy for a hand launch although it would probably still be possible. For what I want, I think the 6s 64mm EDF with retracts will be the best option, balancing good thrust to weight with a reasonable stall speed, good top speed and long flight times, so that's what I'm planning to build the v1 with at this point, but all configurations listed here will be possible.
I've also designed a few wingtip accessories. Wingtip rails give a place to mount either scale-like accessories or things like cameras or airspeed sensors. Dummy tip tanks are great at damping out roll and making the airplane more stable as well as increasing lift a bit. They were very effective at this on my similarly sized F-104.
There will also be a centerline pylon for payloads that need power or a connection to the airplane like gliders or additional avionics with telemetry, or a drop mechanism. I've been meaning to add this to a number of my recent designs, but the pure laminar flow airfoil wings have been a bit too sensitive to things like CG for adding a potentially un-aerodynamic payload that might hurt flight characteristics and shift the lift around a bit. The gear will be fairly tall to avoid any issues with ground clearance.
I'm also continuing to look at the power system and it looks like anything from a 64mm 4s EDF to a 70mm 6s EDF should work, either with retracts, fixed gear, or hand launching (with a gyro for assistance).
Some options won't work well together - for example a 4s 64mm EDF with retracts would be very underpowered and a 70mm 6s EDF would be quite heavy for a hand launch although it would probably still be possible. For what I want, I think the 6s 64mm EDF with retracts will be the best option, balancing good thrust to weight with a reasonable stall speed, good top speed and long flight times, so that's what I'm planning to build the v1 with at this point, but all configurations listed here will be possible.
L Edge
Legendary member
Finally explored flying it and it was very fast at the high end compared to the prop. Bad thing about it, was lacking any rudder control, it tended to skid badly in either left or right turns.
So it became a test vehicle to explore ideas on a dual BWB where the 64EDF's will be mounted above. Will see if it transfer to a dual setup or not. Got only one plane and anyway, if it doesn't work, maybe I can get it to flat spin or my new maneuver, the vertical spin or Pinwheel.
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