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May 02, 2012, 07:45 PM
docinfrance's Avatar
Couple of thoughts.

Maybe I'm missing something (I'm fairly new to quads, ignorant of code and want me bed) but are you trying to run too many things at once (both pitch and speed)? Might be were the resonance is coming from

Why 4 escs and not just the one to keep the blades in sync? Would that not allow control from the board to be handled just by the servos changing pitch?
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Jun 05, 2012, 10:34 AM
Design and fly
skycam4's Avatar
Under the hood of the C700T-Copter

Weíve been working on 2 new designs the past year. One in the helicopter line (0 torque) and one in the multi copter line. Our first concern is safety, first and foremost then reliability, user friendliness, and performance.

The helicopter design will launch Mid July but with this post Iím more interested in why more havenít worked on a collective or variable pitch Quad, T-Copter or Tri? With the rise of injuryís from run offís and false starts by props I can see changes coming.

Why not design a unit that can fly off a typical heli or aircraft motor? (nitro, electrics or the new light weight OS gas) The ability to change ratioís for a large range of KV or higher RPM Nitro engines. With the ability to fly at night by just activating the blades. Can use almost any flight controller from advanced to flybarless.

Single engine, T-Copter shape for less profiling, Ability to carry 2 packs or tanks in parallel or Series, Shaft drive for less power loss , main drive belt to allow for any combination of gear ratios to the main drive, ability to use a canopy, to carry a camera mount or fly 3D. The unit had to be able to with stand a roll over or ground strike.

Couple pics

Just giving the post a bump for the collective guys.

Jun 05, 2012, 11:12 AM
Registered User
rimshotcopter's Avatar
That is really VERY Nice! May I ask how does the Yaw works?
Jun 05, 2012, 11:53 AM
Design and fly
skycam4's Avatar
The unit uses 5mm shafts to drive bevel gears 90 degree's. The rear unit uses a 5mm shaft coupled to a 8mm shaft out the rear that works as the pivot as well as drive for the rear bevel gear. 2 bearings carry the shaft out the tail to the rear carrier that also uses 2 bearings to pivot on working as the rudder.

A pic may help.

Jun 05, 2012, 11:55 AM
Registered User
rimshotcopter's Avatar
Very Nice John!!
Jun 05, 2012, 12:12 PM
Wright's Avatar
Originally Posted by skycam4
Under the hood of the C700T-Copter
The unit had to be able to with stand a roll over or ground strike.
One of the better designs I've seen addressing how to use a single motor and collective pitch. How does it survive a ground strike? I guess the hinged blades help a lot. -- Marcus
Jun 05, 2012, 12:46 PM
Registered User
when do we get to see the proof of concept video
Jun 06, 2012, 01:52 AM
Registered User

Another VP tricopter? How will you stop it from spinning out of control at 0 pitch?

It does look like a very good build, but why put all that time and money into something that is fundamentally flawed?

I'd sure like to see someone prove me wrong.

Any plans for inverted flight? How will you reverse the yaw logic when you go inverted?
Jun 06, 2012, 06:25 AM
Design and fly
skycam4's Avatar
The front two motors 0 themselves out in CW- CCW motion. This complicated the build but you end up with a machine that requires a small amount of pitch to retain the main body direction. This is why the motor is mounted parallel to the main tube. To ď0Ē the torque effect as much as possible. (0 pitch is never used in actual flight). The unit requires +or -6 to stay aloft. For basic mild 3D itís like a heli just fly the sticks. For inverted hovering itís similar to 20 years ago when you flipped the inverted switch. (REVERSING THE TAIL GYRO/Rudder channel on this design) For guys just learning this will help keep the controls the same when inverted.

The unit is actually designed for (safe) stabile flight. Flips , rolls , the ability to run a nitro motor if wanted are bonuses. The T-Copter design was used to eliminate profiling when flying in FF. The single motor was reliability. Variable pitch was used for solid 100% control in any direction. Carbon blades with foam cores are used to eliminate injuryís if blade contact is made. The main idea is a machine you can fly distances like a R/C plane with the ability to take off and land at your feet. Uses the same packs, motorís (electric or nitro), Escís as most 600-700 heliís.

This unit isnít setup like most designs. The elevator is only the rear channel instead of 120ccpm adjusting the front at the same time. Each rotor has a dedicated function which doesnít rely on another reaction to achieve itís direction. 120ccpm theory will generally end up with a unit that is always to sensitive to actually fly once you accomplish a hover. 3D with this would be more like an airplane then a heli.

Jun 06, 2012, 06:28 AM
Registered User
AlexnderH's Avatar
What kind of flight times do you get with that set up?
Jun 06, 2012, 06:32 AM
Suspended Account
Is that a plastic main gear? Anyway, I wonder how much something like this would be . Looks like a lot of custom parts.
Jun 06, 2012, 06:56 AM
Design and fly
skycam4's Avatar
The main drive is Ĺ”belt for the front 2 rotor’s. (split shaft)on the front which transfers via delrin bevel drive gears 90 degree’s to the rear rotor. This is one of two projects I’ve had in R&D for years. Test change, test change and so on… Yeah I’m sure there is a small fortune to this point but that’s part of R&D. Both units I’ve been on are going to launch this summer. I can say we have finally ended up with designs that accomplish what I had set out to.

Run time as it sets with no payload is 14-15 minutes for one 5 cell 5000mah pack. It’s setup to carry 2 packs for extended flight times or motors that require higher cell counts run in series.

On the video question I will get a clip up this week. Right now it's tore down waiting for another motor that is due here Thursday to test.
Jun 06, 2012, 07:01 AM
Nice work and way to persevere with a cool multicopter project...
Quadrocopter and Tricopter Info Mega Link Index
Jun 06, 2012, 07:02 AM
Registered User
rimshotcopter's Avatar
What is the mission of this design? 3D or aerial Photography?
Jun 06, 2012, 07:17 AM
Design and fly
skycam4's Avatar
Aerial Photography is the base for everything we do but with this unit sport flying and 3D are part of the flight envelope. I'm hoping this is a setup that blends 3D guys flying multi's for sport. (Electric or nitro) By changing ratio's and blades this unit can go from a trainer to the limit of the pilot's capabilities.

Thanks Jim. It's outside the box thinking that happened over years as you know.


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