So I tried the Zeph 2 with 6S on APC 7x9 ...

[airtruksrus]

Looked alot like high speed instability, definitely induced oscillations, needed to stiffen up both the elevons or the wing was starting to flex too much.

I wonder if the plane i've got might show some crazy results, not exactly a zeph.

[Toysrme]

wonder how many more people will have issues on these ill designed/constructed (for high speed and/or high G) wings before people learn all the old lessons of how to make them fast without problems?

[londonguy]

The root cause of the failure is that the Z2 is not an unbreakable wing. (does such a thing even exist?)

Mine snapped in half exactly like this in a dive. When you are flying FPV and doing dives from high altitude, it doesn't matter what power system you've got, you can get to over 120 mph in an unpowered dive.

I love the Z2 wing but when my current one breaks I won't be replacing it unless theres a Z3 coming or some other alternative. I flown wings LOS for years and I did that because they were pretty much unbreakable. But the Z2 isn't, it's got quite a weak front end, it does flex quite a bit through the middle with the large battery bay. Combined with the gopro cut out means you've got a very small bit of foam at the front holding everything together. Once that breaks, and it has broken on both of my Z2s, the whole front end can twist around. With how thick the airframe is I'd love to be able to put a 10mm roll wrapped CF tube right through the middle and mount the batteries elsewhere.

My advice to Z2 owners is to keep well under 100mph, so watch your dives. Unpowered dives are worse, it's better to have the throttle on 5% in a dive as the spinning prop slows you down, so if you do need to get down in a hurry you can still do so without going too fast.

[ChrisG]

i wonder how the battery box from TBS changes this....

Hey bro,

I've just finished my Tbs Z2.

I've used the battery box, gopro layer lense box, added a carbon bow spar to the bottom, extended bottom glass spars and glued them to battery box. Lammed it all then monocoat covering over top. I spent a lot of time on the hatch cover lamming it down etc.

I cannot believe how strong it has turned out, I don't think it's too heavy either as CG is spot on!
I've been building slope soarers and DS wings for over 20yrs so hopefully all the knowledge gained will pay off.
Soon as I hinge the cover/ailerons and add the finishing touches I'll post some pics.

Thanx to all the peeps for all great info avail on here... FpvLab Rocks!

[Toysrme]

The root cause of the failure is that the Z2 is not an unbreakable wing. (does such a thing even exist?)

i dont think that's an accurate statement at all. the root cause of failure seems to 100% be a case of ignorance:

designer's ignorance to try to pass off plastic and 3M spray as "durable"
builders ignorance in believing the designer & not knowing what it takes to make something put up with stress
pilots ignorance in trying to out fly the air frame

i think that would be an accurate assessment of why so many FPV planes of all types have the same stress induced issues. (control issue, equipment ejection, air frame failure).

[brosius85]

if you fly the wing inside reasonable parameters it's actully fkn awesome. if you fly outside reasonable parameters it breaks. no news there really. show me another wing of this size that can be built this quickly and handle more speed and you will have me quite surprised. 20 - 150 kph is a pretty good flight envelope if you ask me. you wanna go faster? get a demon 50, or spar the shit outta your ZII. simple.

chris said from the beginning the ZII foam was less durable. so no its not designer's ignorance.

this is what CK gives you when you say you wanna go fast. "plastic and 3m spray" LOL

View this video on YouTube

[Toysrme]

incorrect on several counts.
adding spars does not fix the laundry list of "basic, you should know better" fundamental issues in many airframes being flown today
you will eventually understand that foam itself has nothing to contribute to extreme flight performance applications. in fact, the lighter, the better. even brittle, chunk out, EPS beer cooler foam is far better in extreme applications. foam does not contribute to structural strength. it is simply a cheap, easily & quickly assembled medium that works as a place-holder and former.

its not the airfoil shapes of foamies in use today. from easystars, skywalkers to gliders to flying wings that cause major issue. it's trying to push the inferior build methods beyond what they can put up with. just goes back to the same thing it always does... maybe people should broaden their horizons and learn different build methods before simply jumping off the inferior bridge.



currently, status quo is end user builder & designers both showing ignorance. the only conclusion is that it will simply continue a large number of equipment needlessly lost.

[brosius85]

so what exactly are you suggesteing people do when they want to go fast? get an off the shelf hotliner or pylon racer?

i honestly have no idea where you are going with this. please elaborate

[ZobZibZab]

i like the "ur all doing it wrong" with no input (sanders does that too tho )

that being said, i also broke a wing the same way (not a zephyr, my own). I knew it'd likely break but I still wanted to see how fast i'd go before that. Looks nice when it folds.
I now use a double superposed spar like the Z2 to avoid that, but, my wing is not a speed demon (about 100kmh on 3s)

If I wanted to go really fast I'd go with a much smaller wing area, bigger spars and some strong coverage (fiber or carbon), because light foam will still break even if the spars don't otherwise.

the demon 50 isn't too bad but it could be a lot faster. slope planes/wings are where it's at imo.

[after.burner]

I don't really get the fuzz about this: Did I complain that the wing folded at any point?

For me this "Zephyr 6S Experiment" was great fun: Try to push the wing to something it was not made for. It's like putting a very big engine in a very small car: You know this is pushing the limits and you know it might fail. So when it does you know you went over the limit. This is part of the fun

p.s.
Building a Speed-FPV Plane that will ultimately be driven by 9S right now, hope to reach 250km/h