Just found this video of a dude giving a little coax turbine a workout it is rather awesome .... no problems at all hovering

That is cool, I like coax's but I guess they don't auto rotate very well if the engine poops out.

Yes, I am not sure if they can prerotate? It would be interesting to find out?

That is the highest I have ever seen a coax fly, normally the ones I have seen (Nolan) never get over a few feet off the ground.... the guy in this video is good tho.... I like how he tippy toes his feet on the ground whilst hovering he sure aint scurrrred of flying off backwards

I thought it was a kuuuul video.... looks like a lot of fun

What engine does he have on that one?

There was a video a while back, I think Gabor posted it... of a Russian twin Radial driven Coax... and yeah, it would auto.
Thing belched a bunch of smoke when it started.

Do not remember the name of the aircraft.

This seems to me to be as.close to the concept of a heli in every driveway as possible.
Why not more popular? How unsafe is a coax?

ASK Helicopters sold that 10 years ago it's a RON 1 by GyroDyne a DASH Drone prototype several built both porsch and solar powered from the 1960s once was Bendix Helicopters late 40s, then GyroDyne late 50s to 1990s ,now NELAND they didn't design it at all. . .

tip air brakes for yaw, could auto without any problems, this one was bought at an auction by Arvo of ASK helicopters Los Angeles Ca.

based out of El Monte Airport for a short time, Look up GyroDyne or Navy DASH program or Project Snoopy in Vietnam

Old man Poppadacus was a smart guy. remote piloted drones in the 60s,,,, Now northruop gruman /bell are doing it with bigger airframes carrying less costing lots more, , , QH 50 D was a better drone......Q8s?

I like that video too .... makes me want one

I do not think there is anything unsafe about a coax at all ... but neither is there anything safer about them either ....
except they do not have a "dangerous" tail rotor to snag on a hedge or somebody to walk into

Scratch out a drawing on a napkin Benry , eliminate the tail rotor , then you have to design an exotic transmission
and two rotors shafts turning inside each other in opposite directions with all the controls and all of a sudden
it does not look so easy .... not to mention you still need an appendage sticking out the back for a rudder
and an airfoil in the down-wash to control yaw .... all of a sudden the single main rotor with a tail rotor looks good ;

WHEW !!! never mind all that henry .... I still like that coaxial in the video , I wish it was mine.

Wish you had one too .


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Yes ... like Hillberg says .... he is right , as usual

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thanks hillberg

Rather than posting all of the videos, here is a youtube section showing various coaxial drive methods



https://www.youtube.com/results?search_ ... propellers

awesome, hillbilly.... you aren't just a pretty face.... (even)

http://en.wikipedia.org/wiki/Gyrodyne_RON_Rotorcycle

More

http://www.gyrodynehelicopters.com/the_rotorcycle.htm

Looks to me it wouldn't take much to launch a BRS chute out the front.

i always thought the apaches had brs on top till i found out what it was.
ugly asit is, i think it woukld be a great place for one.

Autorotations are fine you just get yaw reversal in some coaxal types , the QH 50s and RON 1 could auto well,,,,, but in the drone application the fuel shut off was the self destruct (just keep it at full pitch & squish)

The best place for a brs to be launched on a rotary wing thing is under the belly facing rearward (or straight down) if you still have rotors turning, you don't need the chute...... if you need the chute, you will prolly be upside down, so the bottom will be up if you know what I mean.... you will be like an Austr-Alien already ..... so, for example, in a gyro.... if one was to PIO or PPO, you will be bottoms up anyway and the rotors will be out of the way and slowing anyway..... you can still have the cable connected near the head, so when all of the thrashing and whatever stops, you are hanging under the chute (hopefully) right way up ready to land on whatever you are going to land on

That was way too cool !

I love the way he hovers a foot off and tippy toes the machine with his feet on the ground I laughed my head off when I saw that

He made it look way too easy .