I've been working on a new helicopter platform the last few months. Based on an MSH Protos heli which I chose because it's an extremely light weight platform, weighing in at only ~1200g without battery. It has a full belt drive which I much prefer to gears as it's quieter, lower vibration and more reliable. I've had a few problems with it because the belt drive makes a really awesome Van deGraaf generator... not a good thing on a UAV. But I solved that, and am conducting test flights now.
The flight controller is a modified PX4v1. I replaced the switching regulator with a MIC29300, so that I can run it on 2S direct with the servos. Main motor power is 4S 5000, typically this heli would run on 6S 3300. Using the MSH stretch kit and 465mm Spinblade Asymmetric blades. In otherwise standard form, this heli flew for 17 minutes on an old crusty battery, in -10C temperatures.
I have now added a subframe to hold an extra battery, FPV gear with a camera in the nose, and a vibration damped NADIR camera mount to be used for aerial mapping. The idea is to develop a mapping UAV that is superior to a multirotor, offering a valid alternative to a fixed wing for short to medium range missions. The VTOL capabilities would eliminate all the nastiness of catapults, and controlled-crash landings with onboard cameras in rugged areas. Even the price is attractive at about $400 for the basic kit with motor and ESC (no servos).
Specifications show the advantage of a heli platform. This machine has an AUW including the batteries and camera of only ~3kg. It is 80m long, and about 15cm wide not including the extended legs, and 30cm high. The blades fold for easy transport, without requiring any lose wires or vibration-prone electrical connectors as a folding multirotor does. It actually looks much bigger on the table than it really is. This seems to be very good compared to multirotors I've seen with the same performance. (payload and duration)
Vibrations are always a problem with helis, but manageable with the right design and construction techniques.
Arducopter really makes helis worthwhile. You could buy two entire heli systems including a Tx for the price of a single DJI Ace One non-waypoint controller. Or 7 for the cost of a single Ace One waypoint enabled controller. I strongly prefer the PX4 controller over the APM and Pixhawk, because it offers 32-bit performance in a small package that is easier to mount in a heli frame.
So does it work? I took it up for it's first photo tests yesterday, and it worked beautifully. Better than 80% photos are usable. It flies for 20 minutes in a hover with old, cold batteries (-5C). I'm hoping for closer to 30 minutes while actually moving (helis are more efficient moving than hovering), in warmer weather with new batteries. It should have an easy cruising speed of 15 m/s with little or no reduction in flight time. At 20 minutes, this would offer an 18km range, and 27 if it can do 30 minutes. If you wanted to do FPV and not mapping, you could configure it with a 3rd battery in place of the SX260 and fly for... 30-45 minutes, and a range of up to 36km. Top airspeed is still TBD, but probably 20-25 m/s.
Wind penetration and stability is excellent compared to both multirotors and fixed-wing. You could do a mapping mission in winds up to 40 km/h with little effect on stability or duration.
If the success continues, I'm going to consider building a large gasser heli. This would allow flight times up to 2 hours, or payloads on the order of 10 lbs for 30 minutes. So you could map large areas, or even perform light duty spraying operations. I'm thinking about local application of a herbicide for things like Giant Hogweed elimination, that sort of thing. Such a large heli does pose significant danger and should only be used in industrial, agricultural or remote areas.
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The other cool thing about that old Canon PS is that the external DC input is 7.2V. I wired their connector from a stock power supply, (only place I could find it), to an Anyvolt adjustable VR, and got rid of 4 AA batts.
Canon or Nikon or someone needs to make a camera specifically for this application. With 41.5 megapixals, who needs an optical zoom. When I built that setup 8MP was real expensive, I settled for five. I tapped the zoom knob and put a ball joint on it, control arm and servo. Worked awesome, on the ground, No miniature gyro zooms available yet.
"OUR" cam needs high MP count, HDMI and SD output, xlnt lense, and minimal zoom, so less glass in the air, and external DC input, no battery! You could digitally zoom in on something from the ground, and not have the image pixellate, all the while recording HD to an SD card. An intravolameter, I know I mispelled dat, so HD vid, ultra high res stills, and digital zooming on the ground in real time, all at the same time. And small, like a cigar butt.
Get on it Canon!
T
And when that Nokia phone wont cost 700$.....
@Thomas
I like your thinking on the Powershot. DSLR's have no place in AP as the mirror assy is dead weight that is never used.
It also creates lens design problems that result in even more weight. I expect that before long we will be seeing the Nokia 41.5 megapixel cell phone camera in use. when we can work out how to remove it from the phone.
The fixed 5 blade head was the best solution for vibration problems that I found. Also lower head speed. Makes transport a pain though.
Damn, just noticed the last engine actually isn't petrol, but nitro. May not be too problematic to convert to petrol since the owner of Weston also makes spark ignition systems.
Rob, the TT820 has been great so far, a very easy build- the only hiccup was one wrong sized ball for the swash in the kit and needing replacement rudder pushrod guides for the tailboom- niether really an issue. It hasn't flown as yet as I'm still getting my hand back in and confidence up after a having a long break from R/c. I also need to get familiar with a new radio(Futaba14SG) and this new fandagly autopilot jobbie, so 450 at the moment.
First got into helis way back around 1987/8 with a Kyosho Concept flown with an Aero radio, no throttle hold, idle-up or mixing, only a tail gyro...
2 Stroke petrol motors, perhaps multi cylinder would be a way around some of the vibration issues? there is ofcourse balancing and blue printing too. Don't forget that fullsize helis tend to have higher capacity and are de-rated for higher torque and at a lower rpm.
Have a look here: http://www.westonuk.co.uk/westonuk2_036.htm a larger petrol version of the RCV SP engine would give some interesting options.
Looking further: http://www.westonuk.co.uk/westonuk2_047.htm 1 20cc 4 stroke! Would that do?
I thought the same way too about it. It's a really well designed and built frame, but shows its age, so I've spent the last week polishing it and cleaning every inch for his sentimental reasons :) And upon thinking a little more, I believe the heli was larger than 700mm. What would you recommend for an electric heli?
Oliver is 100% correct. If you are not scared, you should go home before you hurt someone.
Here's some of the stuff I was building before I started with multis. This camera carrier did a good job of isolating vibration, thanks to the big draggy water wands. It was a Photoship One Aero-X. No GoPro's then, then APM, just Heli-Command. I chose the Canon Powershot because it had a standard Def video output. These downlinked real time video, and on the coaxial, it was set up for second cam operator. That's it at a Maker Faire.
As you can see, Iv'e been at this awhile. The coax was called the Heli-Baby and came from Infinity Hobby in Taiwan. It was designed in Canada. TBH, it was kind of an Edsel and I gave it to a friend to build a scale Kamov out of it. Really, really hard to tune. 500 size disc, times two, with 600 size mechanics and drivetrain.
The cam carrier also fit a 500, but really needed a 600 to carry it properly. I even built a mechanical shutter release and zoom with servos and linkage rods. Worked great. The new Powershot is awesome.18MP, awesome lens and zoom, full 1080P. Why fly the SLR part when you don't need to? And, Powershots can be controlled by WiFi. Zoom on an RC unit is still really tough to pull off, without rock steady hover, duh.
T
I wouldn't advise putting time or money into a 10 year old platform that doesn't have parts support. That's a fool's errand.
I can't yet recommend any gasser heli, nor even say if the APM will work on it (but I think it can). But I do prefer the design of the Miniature Aircraft Whiplash Gasser. And that's what I'd try if I was buying something right now.
So, I have to ask. One of my sponsors has a 10 year old custom CF 700 frame with a Zenoah 28CC gas engine that (I believe) is just too out of date mechanically wise to bring back to flying order without completely redoing/replacing the head, drivetrain, etc.... It's been in storage for 5-6 years, and the drive train is showing its age. Originally, it had a camera gimbal on the front capable of carrying a TV quality camera or a DSLR and an FPV system. I was looking at replacing it with an autonomous octocopter, but with the potential endurance bonuses from helicopters, should I reconsider? What airframe would you recommend I get to replace the helicopter, under the assumption that I were to get another helicopter? Or, is there anywhere I could go to get help with redesigning the mechanics? Thanks!
(P.S. Proof of how old it is, the clutch is connected to the main shaft with a belt. The tail is direct drive though.)
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