RunRyder RC
 4  Topic Subscribe
WATCH
 2 pages [ <<    <     1     ( 2 )    >    >> ] 1845 views POST REPLY
Scorpion Power Scorpion Power
HelicopterThunder TigerRAPTOR 90 › 3D vs. SE
07-10-2008 05:43 PM  9 years agoPost 21
CBell

rrApprentice

Nova Scotia, Canada

My Posts: All  Forum  Topic

Leadlag,

The helicopter does not roll/flip around the flybar, it does so around the man blades. The flybar is essentially power steering for the main blades. By having the flybar on top you move the blades closer to the engine and electronics, which gives you a higher CG. I'm not saying the R90 has the highest vertical CG out there, but it's not the lowest either.

I tried the kasama head (with the flybar underneath the blades), and didn't like it as much as the stock head. Having said that I don't think it was due to the flybar position.

Remember that the rotor head is the part of the heli that's flying... the rest of the model is just along for the ride. When the R90 is inverted the flybar is below the main rotor, when a machine such as the Stratus or Vibe is inverted, the flybar is above the main blades, relative to the ground and not the mechanics.

Colin

_____________
Align
Thunder Power
OS Engines
Castle Creations
Futaba

PM  EMAIL  GALLERY  Attn:RR
07-10-2008 10:16 PM  9 years agoPost 22
leadlag

rrVeteran

Worthing UK

My Posts: All  Forum  Topic

Hi Colin,

Interesting to hear about the Kasama.I wonder how it would go with a synergy or x-cell head?

Hmmmm.This is where I am coming from.

The heli moves around the CofG not the rotor head(point of lift) just like a fixed wing aircraft rotates around its CofG not the wing. When people talk about a high CoG I think it gets a little confusing.

If you could build the perfect heli that would roll very axially then you would have the rotor/flybar,mechanics and engine right in the same place as the CofG which is impossible.So what people should be saying is probably not a high CofG but the mass or rotor is closest to the CofG on heli-x than heli-Y

I understand how the flybar works. Flybar paddles are like power steering which overcomes the flybar, which when spinning acts as a gyroscope to stabalise the head. But if the flybar (gyroscope) is further away from the CofG which is the point at where the heli rotates around then the heli will not rotate so easily in a roll as the top mounted flybar(gyroscope) has to fly through a wider arc(further way from the CofG) than a underslung flybar(gyroscope) in the same roll.

Phew....hope I make sense.

This is all detract from why my rappy rolls are slower than flips so if you guys could sort it.

I am off holiday so Happy Landings and Il read the thread when I get home.

PM  EMAIL  GALLERY  Attn:RR
07-11-2008 01:23 AM  9 years agoPost 23
CBell

rrApprentice

Nova Scotia, Canada

My Posts: All  Forum  Topic

Discussion on what the heli rolls around aside, the "CG" or vertical center of mass really wont change much by having the flybar above or below the blades. If you set a Raptor 90 next to a Vibe 90 the flybar on the Raptor lines up with the main blades on the Vibe. There is a lot more to where the CG is than that, but I'm sure you can see where I'm going. If you measure the distance from the upper bearing block to the center of the flybar seesaw I think you'll find that it's identical to other helis with a flybar positioned below the main rotor (if you measure to the center of the main rotor hub).

If we start splitting hairs, by having the flybar above the blades we put the rotor hub closer to the center of mass, because there is more weight in the hub/grip assembly than there is in the flybar assembly.

What I'm getting at is that I highly doubt the CG is an issue. Like I've said, the distance from the motor to the rotor head is about average.

Colin

_____________
Align
Thunder Power
OS Engines
Castle Creations
Futaba

PM  EMAIL  GALLERY  Attn:RR
WATCH
 2 pages [ <<    <     1     ( 2 )    >    >> ] 1845 views POST REPLY
Scorpion Power Scorpion Power
HelicopterThunder TigerRAPTOR 90 › 3D vs. SE
 Print TOPIC  Make Suggestion 

 4  Topic Subscribe

Wednesday, September 20 - 4:39 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online