RunCam Twin

[flyin201]

Current version pictured above, read on for the evolution of this project.


I started a thread a while back called "Twin Bloody Wonder" http://forum.flitetest.com/showthread.php?10535-Twin-Bloody-Wonder&highlight=twin+bloody where I started out making a twin motor Bloody Wonder that eventually evolved into an entirely different animal. The end result flew beautifully, however due to loosing signal I crashed it beyond repair. After seeing Josh Bixler's Super Bee I was motivated to make the same airplane again, but this time in a "Mighty Mini" size. Basically I just shrunk my original design down to a size the "F Pack" motors would work on. The other motivation for this project came from a Christmas gift, a RunCam2. I've also sense gotten into FPV and had quite a bit of fun with the FT Arrow, however I felt it was a little wobbly and not quite as precise as an airplane with a rudder for flying through gaps.

In short, the criteria I wanted to meet with this airplane are:

• Compact size
• Twin with "F Pack" motors
• Utilize RunCam
• Use one 2200mah 3s battery

I also integrated into the design a battery pod, basically it allows for easy battery changes without removing the wings and easy access to the FPV equipment.

I didn't take any photos during the construction, but I can provide basic dimensions if you would like to try to build something similar. Here are some photos from the completed project along with a video:

 

[JimCR120]

I've been considering doing a twin for my next project. Are your motors rigged for differential thrust? If so, how do you like it?

 

[LitterBug]

Really nice build and a great area for flying! Thanks for the ride along!

Cheers!
LitterBug

 

[Userofmuchtape&glue]

Wow that is super smooth!

I am saving up for a runcam, gona build a twin too.

 

[flyin201]

I've been considering doing a twin for my next project. Are your motors rigged for differential thrust? If so, how do you like it?

I didn't do differential on this model mainly because it's not as easy to program on the DX6i but also I didn't really feel a need for it, however it does have counter rotating propellers. I did put differential thrust on another model of mine using a v-tail mixer, but for what I do with it (mostly FPV) it isn't much use and a rudder works just fine. That said, I think differential thrust would be very useful in some applications, a float plane for example or acro if you like doing spin maneuvers.

 

[flyin201]

I finally got around to bringing this thing back, and by bring back I mean complete rebuild and fine tunning modifications! I did away with the battery/FPV tray and opted for an open bottom style like the Super Bee. I have a new pair of Focal DVR gogles from Spektrum/Fatshark on the way so I figured it was time to bring it back!

 

[Wingnut pilot]

such a cool fpv ship. very well thought out. even the battery access is cool

 

[flyin201]

Well a maiden flight and any video for that matter will have to wait. Currently in the process of changing jobs, and not only that but moving across the country as well. Hobbies on hold for the moment but if I get the chance to sneak a flight in I will certainly try to document it!

 

[flyin201]

It flies! And quite well once I sorted out the CG, had it too far aft. I calculated the CG AFTER the maiden and I should have known better. I should have built more down angle into the motors as it pitches up more than I would like with throttle, but I programmed in a mix for the elevator to trim down when I add throttle so hopefully that resolves it. Once I get it dialed in I will post some video. The increased wingspan is much better, the previous one was stable and smooth at speed but it was a bullet on landing and stalled far too easy. This one seems to feel the wind and turbulence more but I don't need nearly as much throttle to stay up, in fact 1/4 throttle or less!! It's way overpowered but that should mean I can cruise along with barely any power and get a nice long flight time. With the bigger wing I could probably cram in a much bigger battery so that will be an experiment in the future. I'm hoping the placement of the antennas on opposite ends of the airplane should give some good range as well.

Speaking of range, what dB level is too low for the FrSky transmitters and receivers? I have it programmed to read me the dB, flight time, and volts when I flip the spring loaded switch on the QX7 that way I don't need an OSD.

I added some pop sickle sticks to the belly to give it something to skid on when I land, we'll see how that works!

 

[flyin201]

Montage of video from all the variations of this design.