A few days ago I went back in time. Or to be more precise I started to browse my photo archive. And I've found pictures of my first FPV quadcopter… Oh my… ancient times…
Doesn't it look awkward? At least a little… But this baby was pretty cool to think about it. At least when I finally learned how not to crash every few minutes. If I remember correctly, the specification was more less like this:
Flight controller: CC3D running OpenPilot!
Afro ESC 20A with BLHeli
Turnigy MT2213 935KV motors
10" APC props
FlySky/Tunigy FS-i6 radio link
Some cheap FPV set I've found on HobbyKing with VTX, camera and crappy bucket goggles
Miniquads are fun, right? After all, there is a reasons most uf us flies 210-250 quadcopters. If so, small flying wings should be fun too! I tried that already in late 2015 and failed miserably! My design did not survived maiden flight. Well, things like that happens from time to time, so few months ago, after learning few new things, I’ve made a second attempt. And this time I’ve succeeded.
It is still too early to decide if new Turnigy Graphene are worth the money, but after 3 flying weekends with them I do have some thoughts about them already.
They discharge differently than Turnigy Nano-Tech I'm using in parallel. Discharge curve seems to be flatter
Voltage drop on high load is much smaller comparing to Nano-Tech. Also, they do not regain voltage when disconnected. I usually try to fly until voltage goes below 3.5V per cell. More less 4:30 up to 5 minutes of flight with my regular style. Before charge Nano-tech's voltage usually goes up to 3.7V. With Graphene, it's different story. Before charge voltage per cell is around 3.65V. Maybe it's only half volt, but does tell something about discharge curve and general battery performance
Althought they behave different than Nano-techs, they both accept more less the same charge during load
My Graphenes are new, while Nano-techs not, but Graphenes seems to balance faster. Looks like cells are a better match. I still would have to confirm this
They are indeed quite heavy, but I did not noticed lower flight times or worse performance
LiPo battery life is hard. Charged, discharged, beaten in a crash, charged, discharged and so on. Because last week I had to utilize few of my old Turnigy Nano-tech LiPos, I’ve decided to try something “better” this time. Turnigy Graphene 1300mAh 3S 65C. Package came today and this is what I got:
Box is huge. Really, it would fit 3 LiPos, not just one. Kind of waste. But box is nice enough to reuse for something else
Black is the color of choice here. Black and red. I like this combination
They are noticeably heavier than 1300mAh 3S Nano-tech LiPos. But they have 20C more, so that was predictable
More after the weekend when I should be able to give them a first try.
I’ve bought first Turnigy 2730 1500KV brushless motor by accident. I needed something small and cheap for Depron airboat. Then I needed something similar for a Depron airplane. At the end, in 6 months, I owned 3 T2730 1500KV motors. Not all of them survived the experience. One got lost in the middle of a lake with the rest of airboat it powered. Second got burned what I forced it to power too big propeller. Third one still lives and this type is my first choice for anything up too 400g of weight.
Few months ago I’ve wrote about my first handmade Depron airplane. It was cool design. Super simple, with KFm-2 airfoil, durable and easy to fly. But it had few serious flaws:
motor mounted in front of fuselage is great for flight characteristics, but propellers breaks all the time. Even with prop savers,
big fuselage is not the same as fuselage with a lot of space inside.
That’s why, I have build a second Depron airplane. This time with pusher propeller mounted on a tower behind wing. Wing is almost the same design as in my first airplane. It is still an KFm-2 (Kline-Folgeman, modified) airfoil, 150mm chord, 12mm thick. But is a little shorter: 1200mm instead of 1250mm. The main difference is inside wing. Instead of carbon fiber spars I’ve used two carbon fiber 6mm pipes. That gives plenty of stiffness. Wing almost does not bend in flight, even during hard maneuvers. And generates more than enough lift to give nice, slow flying experience without danger of heavy stall. You really have to want to stall it. And event when it stalls, it recovers nicely: drops a nose, dives for a second or two, and you have lift again. No need to work with rudder, just let it dive and gain speed and then level. Continue reading RedCruiser – DIY Depron airplane for FPV
FlySky FS-i6 (or branded Turnigy TGY-i6) is a very decent 6 channel entry level RC radio system. But support for PPM (CPPM) standard is somehow not clear. I have no idea why manufacturer keeps PPM support data so well hidden. Anyway, here it is: how can I enable PPM on i6 radio system?
It is not possible to enable PPM signal on FS-iA6 receiver. So if you have simpler one, you would have to buy iA6B. Also, PPM signal is not enabled by default. To turn it on, you have to change radio settings:
Open Menu and select “System setup”
Enter “RX Setup”
Navigate to “PPM output”
And change it to “On”
This is all. From now on, FS-iA6B will output PPM 6 channel signal on port 1 labeled “PPM/CH1”.
My 250 class quadcopter project is slowly coming to a successful (hopefully) end. Finally had some time to assemble motors and ESC.
Since I wanted to have rather standard setup with 5×3 propellers, I had no super high demand on ESC, I’ve decided to use Turnigy Multistar 10A V2 ESC preflashed with BLHeli software available at Hobby King. Why them? Cheap, already flashed with BLHeli so no need to to flash at home and 10A is enough to drive 5×3 props. And it’s also enough for 6×3. Just in case.
Motors are also Turnigy bought at Hobby King with 50% discount few months ago: Turnigy Multistar V2 2206 2150KV “Baby Beast”. After discount they were super cheap: $7.5 apiece. And they are green, what goes nicely with carbon fiber ZMR250 frame.
Right now motors are not soldered directly to ESC, I’ve only removed 2mm bullet connectors from both motors and ESC. Waster on space. I’m still thinking about where to put those ESC, so for first few weeks there will be some extra cable between them. Later we will see.
How hard it is to build a RC plane without plans and starter kits? To do it in “Trust me, I’m an engineer” style. In mid June I’ve decided to give it a try and right now I can tell: it’s hard, but not that hard as one might imagine. All the problems I’ve faced were faced previously by someone else. I only had to ask right questions, read a lot, and use engineering sens to make plane work.
And well, it works. Way better than I expected it might work. Look for yourself.
In theory, battery strap should be one of the least important parts of any drone, quadcopter, or any RC device. And no matter what anybody will say, it is one of least important ones. As long, as it keeps battery in place and does not unfasten itself out of nowhere. Especially in flight. So, as an addition to cheap battery straps from ebay/china we can choose something more fancy. Like Turnigy Battery Strap 330mm.