here we go. single vs multirotor

[R_Lefebvre]

Yeah, I saw that. The claim that CF is stiffer than aluminum has me highly suspicious that his prediction tool will be accurate. Sounds to me like they're making the common mistake of using the physical properties of bare CF strand to represent that of CF weave. They are NOT the same.

[xfc3dcd]

Yes. Young's modulus calculations are based off the linear portion of the stress/strain curve. Typically the test specimen is loaded in tension and compression in a tensile testing machine so the loading is parallel to the long axis. CF rod, for example, yields very high numbers in this orientation. We are more interested in deflection under strain of CF multidirectional weaves (tailboom) with the load applied perpendicular to the long axis for the purposes of resonance. When I do my bump tests for modal analysis I apply the impact perpendicular to the tailboom from the side and also the top as I get different values due to the location of the boom supports.

[R_Lefebvre]

It's even worse in flat CF plate. Especially thin CF plate under bending load, where there is only 1 or 2 layers of weave. In this case, none of the fibers are loaded in tension. Rather, you're bending an accordion, and really the stiffness is not much more than that of the epoxy.

I found 1/16" aluminum sheet is stiffer than the same thickness of CF.

[xfc3dcd]

Changing materials is a really good method to address resonance issues in some cases.

I think it's clear now that you can get really great footage from either a SR or MR copter. Also every second that passes, being an FAI caliber pilot is worth less and less as the technology improves. You can take an FAI World title and $8 to a Starbucks and buy a cup of coffee with it. Each day more and more people are getting great looking, stable footage and this trend will only continue. Being a good pilot will always be very important for safety reasons and this won't ever change. I don't fly with autopilot any more than I have to in order to keep my flying skills sharp and I recommend anyone else do the same. As this technology moves forward, being creative will be far more important than being a great pilot.

[R_Lefebvre]

Agreed. I also fly manually as much as possible. I only fly auto for mapping which really can't be done manually. I've also played with using our new Spline Nav function which allows you to set up a virtual 3D dolly track in the sky. You can run the exact same path over and over and over, tweaking it until it's just right. Then you can run it when the talent shows up, or the lighting is just right. Pretty useful function.

But, we also get a lot of people crashing because the autopilot screws up (usually compass problems), and they don't know how to fly manually. It's amazing to see data logs where the aircraft is out of control, but airborn, for a minute or more while the pilot does nothing but watch, or stir the sticks randomly. You see the same thing with other flight controllers too. The majority of DJI "flyaways" are when the autopilot stuff up, and they do nothing.

Autopilot functions are a tool, but flying manually, at least in a Stabilized self-level mode (I only fly Rate mode for fun), should be mandatory. I've flown a 450 heli manually at 1/4 mile distance after the autopilot went bad.

[buhojean]

I've always felt that I have more vibration when I put a tail boom CF than aluminum.

[R_Lefebvre]

Yes, exactly. I've had a 450 tear itself apart on first spool up due to vibrations from a CF boom.

[Bradley90]

Originally Posted by Ivamos

Indenpendent of flying characteristics, cost etc. - there are a lot of advantages by fly the camera with a multirotor.
For professional work with separate pilot and camera operator - will the freedom of camera movement be the most important.
In a typical single rotor setup is the gimbal with camera mounted on front of the heli.


In multirotor setup is the camera underneath the copter.

This solution give the camera operator a lot more of freedoom a dramatically enlarges the efficiency of the work. This means - you can do more complicaded shots easilly and faster. And the shots are what you get pay for.

Is this DLSR camera? it's quite big and heavy to be carried by rc heli.

[Mapoff]

You have got to be a troll. Serious?

[R_Lefebvre]

[ignaceous]

Multirotors are too easy to fly to meet my demands in terms of excitement, and since there is no such thing as a good RTF Single rotor package out there, I had to build my own.





In defense of multis - for every 10 minutes of flighttime I easily spend 5 hours adjusting/prepping/upgrading, but the final product is worth every second.