4s Maiden Report
I'm going to start this by saying, do NOT fly this on 4s.
Started out with perfect CG with a 3300 4s, everything looked solid. I had a friend hand launch for me, used about 3/4 throttle and it got up fine.
After all was trimmed out I tried a couple of high speed passes @ WOT. I have never seen wing flutter like this in my life, violent and I was expecting the plane to snap a wing or take a dirt nap. Down wind or up wind it would flutter aggressively. The wing itself shows strength with the resin/foam construction and the CF rod plus the glass strip but where the evident weakness is the cavity where the aileron servo is mounted. I don't think trying to strengthen the cavity with resin will fix the problem, the flex in the wing is not the issue, it's the lateral twist.
Another problem I encountered was the ailerons at high speeds were showing huge amounts of blow-back, almost no response at all until the plane slowed. The servos seems to be of good quality and I don't think the problem lays with them, its the length/size of the aileron plus it is still foam with flex. Also the tail surfaces were evidently twitchy and unstable at WOT, from either too much air speed or thrust from the fan? Hard to say.
All in all, it was a successful maiden, it is a nice flying plane. The stock electrics/setup seemed to handle 4s quite well, speedy and motor were only just warm after a few WOT passes.
So my recommendations:
~360g 3s 35c+ Lipo
High rates, this is a warm-liner at best, it's clear it is a aerobatic sport flyer. Chasing speed with this will encounter a sad panda face.
It's not a plane for beginners, not that it is hard to fly it's just that it's fairly quick, hard to slow down and not self leveling. Fly it within it's envelope and it's a fantastic plane, I am now going to try turn this in to a aerobatic MACHINE. The tail has so much throw to play with
Pros:
Cheep plane with great gear in it.
Fun to fly.
The noise.
Not many models like it.
Awesome aerobatics and decent gliding capability.
Cons:
4s/highspeed instability within the wings.
Fairly specific Lipos needed.
Needing to re-glue most things that were done from the factory.
I'm not going to lie, I was disappointed that it did not fly well with 4s and I don't think the issue could be rectified but now aiming to go for a more aerobatic path with it. Fly's well, holds great lines and glides fairly well for a overweight glider. It looks sexy as heck and sounds insane. I'd buy another, "plane of the year" I'm still yet to feel that but it is a good plane overall.
A follow up with running 3s!
In my opinion, it fly's better on 3s then on 4. The overall weight is only slightly less but for what ever reason the glide and the aerobatic capability is largely better on 3s.
Firstly, the glide. I'm running 4000mah 3s, I had a flight that lasted well over 20 minuets this morning. Blast it up then back right off to a fairly fast gliding circuit, there was almost zero wind and no thermals, just had to use the speed that plane encourages in a glide to keep altitude and not fight it too much with heavy elevator. When flying with power on, 6.5 mins is fairly safe.
The aerobatics are a bunch of fun, most basic IMAC maneuvers it can complete easily, inverted it's great, the only slight improvement I'd like but I already have is a slight increase to roll rate but I already have the servos at max throw. Something to work on
CoG, I found 80mm to work the best for me, the stall was subtle and the plane seemed to fly better, also no trim needed on the elevator.
Thrust tube! Tried a DIY tube, 58mm exhaust, it did quieten it down but I did gain a 15% increase in thrust. The extra thrust is very evident with back to back tests, with and without the thrust tube.
With about 10 flights on 4s with this plane I was not super excited about the plane, with only a handful of flights on 3s I can't wait to get back out there! It flys like a different plane, super fun! The overall speed between 3s and 4s is not huge, mainly 3s I have not encountered any signs of wing flutter like I do with 4s.
For all the people still humping the dream that this plane will do amazing speeds I still highly recommend to buy another plane to do that with. This plane on 3s is plenty quick enough(with a thrust tube it is more so), I think the denial on terminal velocity on a large wing span of foam is the limiting factor.
TLDR: 3s FTW