Zephyr1
Elite member
Lookin good mate! Except, both those links go to the Mig video ...
Well that is embarrassing...It's fixed now lol
Lookin good mate! Except, both those links go to the Mig video ...
@Zephyr1 - do you now the weight of this? As well as the weight of your EDF? Thinking about going pusher as I have no EDF's and trying to see if I could use an F pack motor.
So the all up weight was 770g with a 2650 4S. The EDF I used weighed 120g. But the wing loading is relatively low as is. So it could work.
Thanks! F pack may be too little but I gave a 2200kv Turnigy that puts out 850 g of thrust. It weighs 50g and my 3s battery would save me as well so I think I’ll be good!
Yeah was figuring I’d have to shift the elevators about 1” forward for prop clearance.
Does this need the ailerons? I though you indicated elevons only? Also where did you splice the fuse together since it’s too long for a single sheet?
Zephry thanks for this great design. I made a few changes from your plans. Re designed the turtle deck to house all of the electronics and added a vented battery tray in the cockpit to hold the battery above the internal ducting using BBQ skewers and a rubber band - battery gets cooling from the duct without being in the duct. All wiring is taped flush with the inside duct to reduce drag. Resized the nose opening slightly and installed a Freewing Mig-21 shock cone to improve the inlet flow. By doing all of that the AUW increased to 31oz but I was able to get the jet flying on an FMS 11 blade 50mm 4S fan unit. Because I fly at a small field I modified the wing reducing aileron span by 10% and adding bottom hinged plan flaps. When deployed the nose pitches up, so to improve pitch authority they are mixed to elevator - 15 degrees at full up stick. Loops, rolls, split-S and Immelmanns are all easily do-able and full throttle low passes are a blast. Launches at 25 degrees flap require a light toss and landings at 40 degrees flap are unbelievably slow - your design has amazing directional stability at low speeds with flaps!!
Awesome design. Cheers, Mate!
Zephyr,
I would definitely be interested in building the new version!! The canopy is a Freewing replacement part - got it for $4.99 and it looks better than my original soda bottle canopy. I'm headed out to HNL tomorrow but will be back Monday afternoon. Got a Masters Series Spitfire on the bench right now and a Ben Harber A-4 awaiting paint.............. but I'd like to build another Mig. I've got a few ideas for modifying the internals a bit more and it'd be a great excuse to do some testing with a bigger fan. Couple of questions:
1) What did your AUW end up being with the 70mm unit and did you bench test the thrust output? I'm only getting around 24oz static thrust on my 50mm fan. Want to get a bench mark for how much duct design and nozzle affect the thrust output of a 64/70mm unit. I know my current set up is maxed out without a cheater hole on 50mm because adding one produced no additional thrust output.
2) What is the heaviest you've flown it? How was the hand launch?
3) Did you test any other wing profiles or experiment with reducing the percentage of span that is under-cambered to get more speed? With the main wing planform being pure Delta it shouldn't have any tip stall tendencies even without under cambered tips and I think you could reduce drag significantly without increasing weight by much by making the wing flat bottomed? I built a "stick figure" swap-able-wing test bed for my Mig 15 and actually used your Mig 17 wing on it along with a flat plate airfoil, a KFm3 and KFm4. Your wing had by far the kindest stall characteristics and looked the best close up, but came in neck and neck with the KFm3 for speed. I opted for the KFm4 because of the shear speed difference on 50mm and the minimal duct restriction with the steps removed - My Mig 15 is seriously slippery although the wing isn't pretty she's a bullet on a 3S 50mm FMS unit.......Faster than the Mig21 on a 4S 50mm by a lot.
4) Will you be attaching your latest version to the first post in this thread?
Thanks for making these plans available Zephyr.
Cheers Mate!