Been on the road for a couple of weeks and was waiting for a few servos before I could finish the wing. Hopefully be home next Monday and get this bird put together. Here’s a quick shot of the wing installed. The front and rear spars dont pass through the duct but instead brace the fuselage from the outside - same concept I used with the KF4 steps on my MiG 15, only this works way better with the wing cross section you designed! They hold the upper fuselage in a perfectly round shape and, when installed, the EDF mounting rings act as an internal former for the lower fuse......my V1 kept bowing in when I would grip it for launch.
Finally home! Servos and fan installed in the wing. Added lower ventral fin to protect the flaps.......at 50 degrees they are almost even with the lower fuse. I can get 65 degrees of deflection with the fin, but I suspect anything more than 45-50 will act less like a flap and more like a lift dump/speed brake.......should make for some fun experiments
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Zephyr, did you add any additional bracing to your horizontal stabilizers with version 2? On V1 I used Elmers ready board for the tail and braced it with bbq skewers..........I used your templates and Adams board on V2 and they seem to have a lot more flex than I expected compared to my V1.........Have you had any issues with flexing/snapping under load?
.Zephyr, did you add any additional bracing to your horizontal stabilizers with version 2? On V1 I used Elmers ready board for the tail and braced it with bbq skewers..........I used your templates and Adams board on V2 and they seem to have a lot more flex than I expected compared to my V1.........Have you had any issues with flexing/snapping under load?
Cosmocop,
Wish I did.........I started with a 25” span version - all freehand drawn sections. Learned you have to arc each section end to get that flowing shape (otherwise it looks like an oddly shaped toilet roll......I wasted a lot of foam board). Also made a stick figure fuselage to test different wing designs - even snagged the wing off Zephyr1’s MiG17 to test the foldover style wing against the others. V1 flew on a FMS 50mm 4S fan and all of the equipment just sorta choked the internal ducting. Flew a bit squirrly but after experimenting with KF4 steps and tapering the steps 40% at the root to less than 25% at the tips it behaved much better......tweeking the CG forward a bit helped too!
Then I discovered Freewing does a 64mm EDF MiG15 for about $100 and knew I could build my own for a fraction of that. Decided to scale mine up to 31” span and use Freewing replacement parts for the intake ring and cockpit - at 31” span they fit PERFECTLY! Originally I planned to make templates of my body sections as I built them but discovered that the taper at the tail pipe looked ridiculous when I tried to scale up my V1, so I made a couple of different tapers and rolls and ended up adding a 5th fuselage section to the tail.........during all that fiddling and tinkering I managed to glue it all together......without making templates. The beauty of the larger span (V2) was that I was able to lift all the electronics out of the duct and even though it’s heavier than V1 (and the Freewing 64mm EDF) it’s faster and flys longer on a less powerful 3S 50mm fan.
I’d be happy to snap some closeups of the internals if it helps you any also, If - - - When I crash it I’ll cut apart the tubes and flatten then to make templates..........Although I have no clue how to make plans I’d be happy to fold them up and send them to you. It’s a really great flying little jet. Super stable, easy to fly and unlike some of the Freewing reviews its really easy to hand launch and with a 2200mah 3S you can get an easy 5-6 mins of mixed throttle out of it.
Cheers,
Mac.
Wish I did.........I started with a 25” span version - all freehand drawn sections. Learned you have to arc each section end to get that flowing shape (otherwise it looks like an oddly shaped toilet roll
......I wasted a lot of foam board). Also made a stick figure fuselage to test different wing designs - even snagged the wing off Zephyr1’s MiG17 to test the foldover style wing against the others. V1 flew on a FMS 50mm 4S fan and all of the equipment just sorta choked the internal ducting. Flew a bit squirrly but after experimenting with KF4 steps and tapering the steps 40% at the root to less than 25% at the tips it behaved much better......tweeking the CG forward a bit helped too! Then I discovered Freewing does a 64mm EDF MiG15 for about $100 and knew I could build my own for a fraction of that. Decided to scale mine up to 31” span and use Freewing replacement parts for the intake ring and cockpit - at 31” span they fit PERFECTLY! Originally I planned to make templates of my body sections as I built them but discovered that the taper at the tail pipe looked ridiculous when I tried to scale up my V1, so I made a couple of different tapers and rolls and ended up adding a 5th fuselage section to the tail.........during all that fiddling and tinkering I managed to glue it all together......without making templates
. The beauty of the larger span (V2) was that I was able to lift all the electronics out of the duct and even though it’s heavier than V1 (and the Freewing 64mm EDF) it’s faster and flys longer on a less powerful 3S 50mm fan.I’d be happy to snap some closeups of the internals if it helps you any also, If - - - When I crash it I’ll cut apart the tubes and flatten then to make templates..........Although I have no clue how to make plans I’d be happy to fold them up and send them to you. It’s a really great flying little jet. Super stable, easy to fly and unlike some of the Freewing reviews its really easy to hand launch and with a 2200mah 3S you can get an easy 5-6 mins of mixed throttle out of it.
Cheers,
Mac.
It looks awesome. No need to send me anything. If you do ever make plans please post them. I've made the Mig-17 but I don't think Zephyr has posted a 'smooth' version. I also had some thrust angle issues with that one and had to put the battery hanging out the nose to balance.
Cosmocop - you almost got a set of plans today......The battery came loose and slid back a half inch. Was Mr. Toad’s wild ride all the way to the ground. I think I’ll install the small foam back stop that I kept saying I was going to glue in.
Zephyr - the 64mm EDF version maidened today. Lessons learned:
1) By moving the fan forward into the wing and moving the battery aft to balance it the aircraft need far less tail down force to achieve level flight. I launched it with the same tail trim and CG location as the V1 50mm and it pitched up violently and required 50% nose down trim to maintain level flight. Once trimmed it tracked like an arrow. Now it requires very little back pressure to maintain altitude in turns and is much more responsive in pitch than the V1 theoretically this change alone should increase the top speed due to reduction of trim drag. Aileron effectiveness remains the same (which is awesome!), I think moving to a fully flat bottomed airfoil was a good call.
2) Glueing two small strips of 120 Grit sand paper to the lower fuse makes gripping it for hand launch much easier.
3) The split flap design, whilst not scale, is UNBELIEVABLY effective!!! At 60 degrees deflection it requires less nose down trim than V1 with it’s plain flap design at 40 degrees and produces a ton of drag. It needs about 25% throttle in the glide and when you want to land you just chop power and hold the nose up - it literally just sits down..
Love this airplane, Mate! Now it’s time to build the turtle deck and give her a coat of paint!
cheers,
Mac.
.Zephyr - the 64mm EDF version maidened today. Lessons learned:
1) By moving the fan forward into the wing and moving the battery aft to balance it the aircraft need far less tail down force to achieve level flight. I launched it with the same tail trim and CG location as the V1 50mm and it pitched up violently and required 50% nose down trim to maintain level flight. Once trimmed it tracked like an arrow. Now it requires very little back pressure to maintain altitude in turns and is much more responsive in pitch than the V1 theoretically this change alone should increase the top speed due to reduction of trim drag. Aileron effectiveness remains the same (which is awesome!), I think moving to a fully flat bottomed airfoil was a good call.
2) Glueing two small strips of 120 Grit sand paper to the lower fuse makes gripping it for hand launch much easier.
3) The split flap design, whilst not scale, is UNBELIEVABLY effective!!! At 60 degrees deflection it requires less nose down trim than V1 with it’s plain flap design at 40 degrees and produces a ton of drag. It needs about 25% throttle in the glide and when you want to land you just chop power and hold the nose up - it literally just sits down.
.Love this airplane, Mate! Now it’s time to build the turtle deck and give her a coat of paint!
cheers,
Mac.
4 flights on V2 and she flys great.......a lot more speed and definitely feels heavier (36.7oz) which makes maneuvering in my small park area a bit more stressful, but she’s can be slowed to ridiculous speeds with the flaps out and if you come up short on the approach you can hold crazy high alpha just by working the throttle. This is an awesome Jet - lots of fun. Still need to finish the turtle deck (the current one is an ugly place holder until I figure out the final hatch design) and then finish the leading edge of the vertical stab to fair it into the upper deck.
