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Popwing 900mm and Tecsumo FPV build and test flight

#1
I started this hobby with only experiance from flying aircraft in games. Namely 20 years ago on amiga computer. I didnt want to buy a simulator so i got a Hitec Skyscout (multiplex easystar 2) and a Turnigy 9X radio for it. After crashing it numerous times i got a HK Atom be able to handle the crashes better and fly in smaller areas. That said. I came into the hobby with FPV in mind. So as soon as i felt i could control the plane a bit i put FPV gear on my skyscout. Omg ORGASM ! first time i flew it it was so extremely intense experience !

I started doing "lunch" fpv. I went home for lunch and instead i went and flew FPV on a lake nearby. Just short 10-15 min flights. However. Since doing that i have wanted something that could carry a go pro comfortably. I never managed to fit that well on the Skyscout. It just required to much speed. Anyhow. I started wanting a wing. A RVjet or a go discover. Then the skymule came. I wanted that. I got the skymule. It was fun to fly and could handle the go pro with ease ! However, it was too much of a hassle to carry that huge plane for 2 km out on the lake each time i wanted to go fly. So i started thinking of a wing again. A small wing. A Hacker skyfighter i thought of first. That looked nice 500 mm and with a digital camera on etc and FPV gear i could take it anywhere !

Then the amazing thing happens i google "long range FPV tecsumo" or something like that and find: http://www.flitetest.com/articles/how-to-make-a-long-range-small-techsumo-popwing

I had prior to that watched his youtube videos of FPV flights with his popwing. I scratched the idea of a hacker skyfighter. I got the 900 mm Popwing instead. It was on sale 25% off normal price, engine included for less than $50 !

So my initial setup (which flew horribly) was the stock setup with a 1200 mAh battery in the compartment in the front. I have 18 A esc and a frsky receiver in it. CG was not right.

I added FPV equipment to it:
Fatshark 600 TVL camera,
Fatshark 250mW video TX with cloverleaf antennas

After trimming it it was still very sensitive for elevator up down. Extremly sensitive ! Not even this was enough to get the CG right. It turned nice and docile. But try elevator up and down and it just did a loop ! Ok i suffered for a few flights like that. I added a battery in front to get the CG more right. It got better but still sensitive. Finaly i decided ok ill add the mobius to it (now i could fly this instable wing without crashing it to badly)

With mobius on top i removed the extra battery i had as ballast. Damn CG was not right even with mobius on top. I added a bracket and hot glued it to front tip of the plane. CG was correct !

So for the first time i would fly this wing with CG correct. It took full FPV gear, a 1200 mAh battery, a mobius and a bracket as weight in the front to get the CG right.

Launching it was terrible. It crashed nose first into the ground. Nothing happend. Not a scratch on anything. Launched it again. This time it flew perfectly. It cut through the wind no problem at all. Ah... damn it now was a joy to fly. I flew 2 batteries, 7 min each (didnt have any osd so i had no idea how much battery i might use). Came home and recharged them. One battery i put in 400 mAh in. The other 600mAh. They had been used a bit before this so they where not totaly full. Home and charge them again. I started with crashing it nose first into the ground again. I figured out what was the reason. I didnt launch straight into the wind so it wanted to turn to the side directly. Once i trottled up more and launched into the wind it flew straight as an arrow. It climed extremly well.

So I must say this plane is my total favorite for FPV. It is steady. It doesnt cost much. It is easy to carry and it has small batteries. Unfortunatly my frequent crashing on first launch lead to the mobius almost falling off. It had horrible jello. It didnt to begin with but after crashing it so it almost was totaly lose it did. I attached the mobius by hotgluing it directly to a piece of foam that i hotglued to the middle of the airframe so it protrudes out over the battery compartment. It was perfect mount and worked really well until i crashed it to many times.

Things that has broken down for me:
The nose.
Two servos. I have the cheapest el cheapo servos you still have to pay something for. I wish i had purchased servos with metal gears. I stripped gears of one servo and i broke one (unsure how it just jammed up). Needless to say you dont want to spend time switching servos when its flying weather. You want to fly. I have never broken any servo on a airplane until i started with this flying wing. Now i have broken two servos in no time. So i think getting servos that can take a beating is a good idea.
The ailerons have come lose. Luckily the supplied tape can fix that.
Split the fuselage in the middle when i nose dived att full trottle into ice, that is also when the nose broke and flew away including the flight battery. Battery was unharmed tho.

Mods i have made:
I mounted the servos on the top side.
I mounted the battery on top side. I carved away the "top" and used that as bottom for the battery compartment. I hotglued a piece of plastic into the battarey compartment and attached velcro on that and another velcro on eachbattery. Works perfectly. The old battery strap did not work at all for me. It came lose so frequently in crashes so i didnt want to have that wooden thing in there anymore. The plastic i used was from a food container so its a bit flexible so it dont come lose in crashes. The battery does how ever. Saves the battery i think.
Attached the nose with hot glue (a bit flexible also)
"removed" the small foam vedge that is ment to be under the nose. I replaced it with half a icecream stick. I never understood why the foam wedge had to stick out half an inch ? It always comes lose on landings. This icecream stick saves the underside of the plane better than the piece of foam ever did.
All electronics mounted with hot glue in the "electronics bay" on the underside of the wing. I put a plastic lid over it and used some hot glue to glue that in place. No hassle with the electronics. Worked like a charm.

In summary:
The recommended battery for the popwing will never ever ever ever get the CG right on that wing unless you put it on a stick infront of the wing.
You need lead or something to put weight on the nose. In my case that "something" was FPV gear and mobius camera. Now i love this little wing. It flies amazing ! I will post some flight vids after gluing the camera back on. I got one from the maiden also. And one from a crash when i launched it :D

Happy flying, happy easter and watch out for the witches !

Carolus Rex
 

mreby

Junior Member
#2
I bought a mini popwing and I'm building an fpv backpack for it. A cam, battery,antenna and transmitter with Velcro on bottom so I can go from plane to plane with it.
I love this plane. It's portable,fast,slow and almost indestructible.

Here is my mini popwing video. Crank the volume!
 
#3
Nice flying :)

here is the video from the maiden. It was a bit too much jello in it. When trottle is above 50% it gives that nice jello effect aparently :D. I will attach the camera a bit better and same with the wires etc that might be causing vibrations.

-Carolus Rex
 
#4
Today i did a horrible crash. The sky was grey, the ground was grey. I took of the goggels to see that i was oriented towards the plane since i was flying with the antenna on the goggels (predator V2) and the plane had just started and was cruising straight forward at my normal FPV altitude somewhere between 50-100m up i would believe (No OSD on it) and i put the goggels on. Did i see the sky or the ground ? I dont know. I pulled up and smacked into the ground full trottle :D The sound was a double smack in the ice. I thought ouch lets hope that was not the mobius. But no. Mobius was still glued onto the piece of styrofoam i use for mount. The second smack into the ice was the engine that had ripped away the engine mount and a huge chunk of the middle section and smacked it all into the ice, at same time gutting the equipment bay under the plane ripping out everything that was hot glued in place !!. I looked at the plane and thought "ok this is probably not going to fly again". I took the pieces and tried to put it together at the lake. Seems everything was there.


Fuselage fixed:
Now i have glued the fuselage together and it looks like new. You cant even see it has been ripped to pieces unless you know what to look for. The miracle of CA and activator... Problem is that i think many of the small thin straw type spars that are there are broken in manys mall pieces. Those that are not broken are lose so when you bend the foam they dont resist it. So the wing is incredibly flexible now compared to what it was when new. I think perhaps a reason it crashed was that one servo is missing a tooth. So it is not flying straight all the time. Dont know if its because of that or windy conditions.

Todo before going airborne again:
Add more spars so it doesnt flex so much. If i have enough CA glue ill do that now.
Change the "semibroken" servo
Reattach the FPV cam
Reattach the mobius
Re glue the power connector on the fatshark VTX (the soldering is ok but the connector is moving so eventually it will cause enough stress on the soldering joint so that one will come lose also if its not glued in place) shrink wrap the Fatshark 250mW VTX and reattach it with hot glue to the fuselage.
Re solder and shorten all servo wires.
Test the engine so its ok.
Replace the broken prop. First prop i ever broke on this one. It had a propsaver also but still it broke the prop.
Set failsafe on the frsk receiver
Rebuild the "equipmentbay" cover to prevent snow from entering the compartment where the receiver and ESC are located.

After this crash i was thinking that the most likely crash is at launch since it is very easy to land but with mobius on its abit of hassle to launch. But launching it into the wind makes it fairly easy. It flies so beutifully now. Anyhow i thought it would be cool to have some kind of bungy launching device for it in order to decrease the risk of crash at launch.

Carolus Rex Easter FPV gone wild :D
 
#5
One thing i did before i crashed so horribly was to mount the camera more foreward on the wing so it was looking downwards in a angle. This made me automatically fly higher and also get a more enjoyable FPV experiance. I have started mounting the cameras with hot glue. It is fairly easy to remove and it gives some jello damping effects i have noticed on my mobius.

Now i mounted the camera on a HK skipper and its mounted on the front and i think its on a pretty steep angle downwards. Probably something like 35 degrees from the horizon. I have not yet flown it FPV yet but i think it will make me fly higher yet. It was so incredibly wonderful to fly with the camera pointing a bit down on the wing. So i thnk having it point even more down (like now) will be very good also.

-Carolus Rex out in the sun
 
#6
After flying the wing daily for about a month i must say that the popwing is amazing. With everything, 1200 mAh battery, 250 mW 5.8 GHz, 600 TVL fpv camera, Mobius, power filter, frsky receiver and a "hatch" on the bottom the thing weighs about 500grams and handles vind very well. I live up north in sweden near the coast and its always windy here. No problem for this baby. I have comfortably flown it in winds around 6 m/s with gusts up to 10 m/s. I had some issues with it because the CG was off. But getting the CG right (it got right when i put mobius on it) and trimming it i must say i love this wing. It is now my goto plane. So sturdy and easy to fly. The feeling when FPV:ing with is total immersion. My horrible crash with this wing ripped it apart and ripped the engine out of it and a huge chunk of foam got ripped out. I tried to glue it together with CA glue. But aparently i missed something since i flew it and there was horrible jello. So i checked it for cracks and turns out it still had a big crack. Instead of CA i used hot glue and "injected" it into the crack. Result was amazing. So i highly recomend "injection" when you got cracks that go through the wing. I used a spoon to hold the crack open (just showed the handle in so it was held open one mm. Then i used the glue gun and pushed in glu along the crack. I pulled out the spoon and filled that space also and then pushed the thing together. After doing that repair i also added a second thicker spar on the upper side of the wing exactly where the "original" spar is near the engine mount. I glued that one in using hot glue. It works much better than the CA glue. CA seems to detatch from the spar during a crash and the wing becomes flexible again. Hot glue is a bit flexible so it does not rip out of the wing and stays glued together. That means that the spar will stay in better.

In short, i added a couple of spars and hot glued them in. The wing is very stiff now. The jello problems i had (probably due to many crashes made the wing flexible due to the spars mounted with CA, are now gone.

/Carolus Rex