1 bladed heli!!!

Sort of interesting in a way with the one bladed concept, looks like it's giving better efficiency, but I can't see the point of a helicopter that has to be kept in relatively high forward motion to maintain stable flight. The whole point of helicopters is there ability to hover and move in any direction

By the looks of it Brian, it is one of those helicopters that would need to be flown in forward flight anyway. It certainly doesn't have a full collective pitch head on board.

There is absolutely no reason why a single bladed helictoper would not fly anyway. I'm pretty sure that whipping a blade off a Trex 600 (for example) and replacing it with a balancing mass in just the right place, would result in a perfectly flyable heli. There would be a pretty sharp decrease in the roll/pitch rate available, and the collective authority would more than likely drop a little, but it would fly. However, getting the balancing mass in just the right place over the entire operating envelope would be a major PITA. It's far easier just to replace it with another identical blade and have it do something useful

Here's a prediction for the future too. Multi-bladed 3D helicopters. I reckon it is only a matter of time before one of the ninja 3D helictoper pilots, that have a fair bit of influence over a manufacturer (eg Align), realises that if they swap their 2 bladed Flybarless head, for a four bladed flybarless head, reduced the blade size a bit, and then went and flew it, they would find that their heli is a bit more responsive, agile and powerful. More complicated mechanically, but no more so than a flybarred heli....

Andy

Might be interesting if the video would play instead of just displaying a message about accepting the poster a a friend and the taking you to the Youtube sign in page wierd.

Looks like they have changed the vid to private

M

https://www.youtube.com/watch?v=T2srv2EZgbA

Well that seemed to fly OK, the first one said "removed by the user".

Been there ........
Andy, I used to make and balance my own blades in the days of Hickory LE and tapered Balsa TE.
As far as balancing goes, this is just balancing two arms in a single plane.

Each blade (or counterweight) MUST have identical weight/mass. Obviously there will be a difference at first. Find out what that difference X is.
Then
Both Blade/Arm MUST balance perfectly when balanced opposite each other on a pivoted rotor cross shaft.

The trick is to place the correction weight X on the light blade/arm at the only place where there is perfect balance. Fix it (without adding more weight).

Job Done

If you're not sure
Weigh each blade/arm again and confirm they are still identical mass.
Check they truly balance opposite each other on a balancing shaft
If still slightly out
Use two equal narrow 1/4" solartrim strips to correct the error of fixing the weight X .
Place one outboard on the light blade/arm and then the other inboard on the other blade/ arm. Maybe use wider strips if you used too much glue. Iron on to seal.

I found with wooden blades, a tight weight tolerance below 1/2 gram was a waste of time because wood blades change mass absorbing/losing atmospheric moisture all the time.

Andy your wish came true at the beginning of this year by a company called Sports moto.
They do scale and 3D multiblade heads for all the trex range and for the Curtis youngblood Rave 450.
Model helicopter world reviewed the Rave 450 4 head conversion using a variety of blades from wood to carbon and it looked quite nicely made.
There didn't appear to be any performance gain that they noted though,tracking was interesting and transport is a bit trickier as you can't just fold them all away as normal.
Also if you like to spank carbon blades you could easily kill 4 instead of 2.
Checkout their link,
http://www.sportsmoto.co.uk/acatalog/Multi_Blade_Heads.html
They do quad tails as well.
Some of their stuff looks gorgeous.
Does Andy want to try one?

Danny

Mmmmmmmm....

Along with big flaps, I do like multi-blade heads.....

Andy

Here we are, the video was pulled dwon by youtube becasue of a music issue so here it is re-uploaded
https://www.youtube.com/watch?v=AD9juUWL5iU&feature=sub

Glad you were able to re-post the video

His demo model flew very well, maybe there is only need for 1 main blade.

I know they use single blade propellors (with counter-ballance) in top line competition c/l speed models to gain better propellor efficiency at the high revs used.

There is another thread about single blade props Paul
https://rdmfc.forumotion.co.uk/general-discussion-f1/1-bladed-prop-t2002.htm