telnar1236
Elite member
Most of my 3D printed planes so far have either been very experimental (tailless planes, early modular designs), highly loaded (F-104, Gee Bee, MiG 15), or designed to be gentle flying and carry a lot of load (modular trainer/base plane). But now I want to build something that is high-performance and capable of a wide range of maneuvers - a true fighter. So of course, I decided to build the ultimate interceptor, the F-106 instead.
However, in reality and as a scale plane, the F-106 is actually more maneuverable than a lot of dedicated fighter designs. Its big delta wing gives it low wing loading and a ton of angle of attack capability. Built with 6s, I expect this design to be faster than 100 mph but to be able to come to a near stop in the air. While it will have a rudder for easier landing, it is going to be built mostly as a bank and yank design intended to fly at a positive angle of attack (although it will be capable of inverted flight of course).
This jet incorporates a lot of what I have learned from my previous designs. It should have much robust structure than the F-104 and Gee Bee (more in keeping with the modular trainer) but have a lighter 3D printed structure than any of them (the AUW will be higher since it is a 6s design). The ducting should be more efficient than any of my jets except for the MiG 15 without having as many sharp angles as the F-104 or the wing spar through the center like the modular trainer. And the thrust line is right through the CG so it should be well behaved at all throttle settings. The hatch is a new design that sits much more stably in the fuselage. While none of the hatches are prone to flying off, this design always sits in the right place immediately without any finagling.
And this design also incorporates new features unique to it. It has a 3D printed clear canopy in keeping with the MiG 15, but this canopy can open to allow for a scale cockpit or possibly an FPV cockpit (with molded plastic, not 3D printed windows) sometime down the road. It has operating air brakes, more for aesthetics than anything else. It will have gear doors for all the gear, although they are not designed yet and the first flight will probably take place without them. And it has an internal payload bay, like the real F-106, so it can carry dummy bombs or possibly even a much smaller EDF "missile."
On top of these features, it has improvements to the assembly process. More of it is screwed and locked together mechanically and less is glued when compared to my previous designs. It does not use the same modular system as my other planes for the last couple of years since the fuselage is not circular, but the new system, while requiring more screws, is simpler to assemble. The servos also now screw into place and are covered by 3D printed material instead of being glued.
The power system was originally intended to be a 70mm Powerfun EDF (the 6s version of the original power system in the F-104) but recent bad experiences with that EDF mean that I have switched to the X-Fly 70mm fan instead, which just about fits in the same footprint. This should have the positive effect of giving the plane an extra 150 g of thrust. The retracts are the same Freewing units as the F-104 since they are reliable and lightweight.
To improve high angle of attack handling and energy retention, the wings have 7 degrees of washout and a conical camber (like the real plane). The wing root starts as an almost symmetrical airfoil before progressing to have a fair bit of camber at the middle of the wing. By the time the wing reaches the tip, the whole airfoil has a negative incidence angle compared to the root. Using 3D printing instead of foam also lets me make the wing tips very thin (only a couple mm) which improves looks and should reduce drag too.
The plane will have a final length of 51.9", a final wingspan of 30", and final height of 16.2" with the gear extended. Final AUW will be about 2.2 kg with about 2.4 kg of thrust so the performance should be exceptional.
However, in reality and as a scale plane, the F-106 is actually more maneuverable than a lot of dedicated fighter designs. Its big delta wing gives it low wing loading and a ton of angle of attack capability. Built with 6s, I expect this design to be faster than 100 mph but to be able to come to a near stop in the air. While it will have a rudder for easier landing, it is going to be built mostly as a bank and yank design intended to fly at a positive angle of attack (although it will be capable of inverted flight of course).
This jet incorporates a lot of what I have learned from my previous designs. It should have much robust structure than the F-104 and Gee Bee (more in keeping with the modular trainer) but have a lighter 3D printed structure than any of them (the AUW will be higher since it is a 6s design). The ducting should be more efficient than any of my jets except for the MiG 15 without having as many sharp angles as the F-104 or the wing spar through the center like the modular trainer. And the thrust line is right through the CG so it should be well behaved at all throttle settings. The hatch is a new design that sits much more stably in the fuselage. While none of the hatches are prone to flying off, this design always sits in the right place immediately without any finagling.
And this design also incorporates new features unique to it. It has a 3D printed clear canopy in keeping with the MiG 15, but this canopy can open to allow for a scale cockpit or possibly an FPV cockpit (with molded plastic, not 3D printed windows) sometime down the road. It has operating air brakes, more for aesthetics than anything else. It will have gear doors for all the gear, although they are not designed yet and the first flight will probably take place without them. And it has an internal payload bay, like the real F-106, so it can carry dummy bombs or possibly even a much smaller EDF "missile."
On top of these features, it has improvements to the assembly process. More of it is screwed and locked together mechanically and less is glued when compared to my previous designs. It does not use the same modular system as my other planes for the last couple of years since the fuselage is not circular, but the new system, while requiring more screws, is simpler to assemble. The servos also now screw into place and are covered by 3D printed material instead of being glued.
The power system was originally intended to be a 70mm Powerfun EDF (the 6s version of the original power system in the F-104) but recent bad experiences with that EDF mean that I have switched to the X-Fly 70mm fan instead, which just about fits in the same footprint. This should have the positive effect of giving the plane an extra 150 g of thrust. The retracts are the same Freewing units as the F-104 since they are reliable and lightweight.
To improve high angle of attack handling and energy retention, the wings have 7 degrees of washout and a conical camber (like the real plane). The wing root starts as an almost symmetrical airfoil before progressing to have a fair bit of camber at the middle of the wing. By the time the wing reaches the tip, the whole airfoil has a negative incidence angle compared to the root. Using 3D printing instead of foam also lets me make the wing tips very thin (only a couple mm) which improves looks and should reduce drag too.
The plane will have a final length of 51.9", a final wingspan of 30", and final height of 16.2" with the gear extended. Final AUW will be about 2.2 kg with about 2.4 kg of thrust so the performance should be exceptional.
