Flying Project

[Fishy Jim]

I'm curious how you ended up with 4' rotor blades and what calculations did you follow for determining the airfoil's form other than making it look like a wing? How much thrust will the rotors create for your given rpm sweet spot?

[monte55]

I'm curious how you ended up with 4' rotor blades and what calculations did you follow for determining the airfoil's form other than making it look like a wing? How much thrust will the rotors create for your given rpm sweet spot?

Four foot rotors was a guess compared to looking at similar type units and that's the longest my cnc can move in the X axis. The shape of the rotor is based on the 8-H-12 airfoil. Don't know how much thrust yet as that will depend on rotor pitch, speed, rpm, and whether the engine is up to the task.

[monte55]

I'm not following the scary part... just find a test pilot.

BTW... Do you plan to free fly, once the rotors are attached, or have you considered suspending it between ropes, until you get the feel for it? The problems encountered with learning to fly a device intuitively are not only in controlling the vehicle's attitude, but also in controlling your excitement. Overcorrecting a change in attitude often leads to crashes.

BTW2... You've done a remarkable job. I share your excitement. Continued success.

It will be teathered down while running with rotors untill drive train etc prove
to be ok. Then will try with a little slack.

[Goodhand]

It will be teathered down while running with rotors untill drive train etc prove
to be ok. Then will try with a little slack.

Not sure I can wait for the video of your first flying attempt... do you mind if I drive over to watch?

[monte55]

Not sure I can wait for the video of your first flying attempt... do you mind if I drive over to watch?

I'm sure you're joking but early testing will be without spectators for safety reasons.
Nick

[Goodhand]

I'm sure you're joking but early testing will be without spectators for safety reasons.
Nick

I've got binoculars.

[monte55]

I've got binoculars.

So.........you're are pulling the old bino ploy? I get it

[monte55]

I put the two lower rotor blades on the heli and did a short and limited
rpm runup. First I noticed some vibration which I need to figure out. The
centrifigual clutch has a spacer bearing that is like a sprague clutch for lack
of better description. I'm not quite sure exactly what purpose it served in its
4 wheeler application. Maybe for engine braking when the throttle was released.
Anyway I reversed it on installation on the heli so only the clutch shoes would
drive the rotors and not this bearing upon start up. The problem now is when I
throttle down the engine which will slow down quickly, the rotors slowing down
want to drive the engine if that makes any sense. They should free wheel but
they tend to drive the engine and jerk the rotors and drive train a bit at shut
down as can be seen in the video. This bearing has to go and I'll have to make a
spacer bearing to replace this one. So as long as the clutch shoes are not
expanded, the rotors are totally free of the drive system to rotate.
Next....with only the lower rotors spinning, the gyro effect(rigidity in space)
make changing the angle of the rotor head via the handle requiring more effort
because of this effect. When I shut the engine down, the rotors should free
wheel to a stop. Maybe the gyro effect will change when all four rotors are on
and turning. They may cancel out each a bit. We'll see.
Nick
http://www.youtube.com/watch?v=PA-VpL0vAIo

[Fishy Jim]

When you add more rotational mass, it will increase the gyroscopic effect - doesn't matter that they're opposing each other.

[monte55]

I realize the more weight and speed, the more gyro effect. I'm talking about a single rotating mass and the 90 degree effect when trying to move it from its plane of rotation. I wonder how the opposite 90 degree effect of the top rotor will effect this.