"Hawkdoc" wrote in message
...


Back to the pencil it now marks a spot on the side opposite
the heavy side so that corrective weights must be located by "Add Same".
This techniqu has gotten me balancer readings down below 0.1 ips.
(Military
says anything below 0.4 is ok)

I think you need to redo it until it's 0.0 ips. Job's not worth doin'
unless it's done right!

Stu, not sure where you got the .4 standard from. On US Army rotorcraft
the standard was for .2 IPS in all modes (ground, hover and flight Vne).
Some birds where impossible to get all three so we always went with hover
and flight. Some of the reasons could be structural, mechanical or even
the flight hours on the individual blades.

Kevin, 0.0 sounds nice but, is an impossible quest. To many outside
factors in play to ever achieve (wind, temp, age, even sunlight). I've had
birds down below .1 IPS and couldn't tell the differance with others at
.3. Besides 1 to 1's aren't bad in comparisson to 2 to 1's (tail rotor).
2V1 are the ones that make a lousy flight on a clear smooth day, the ones
that can make you feel sick and listless. 2V1 are the buzz in the controls
that put your body to sleep.

James
Rule #1 Always remember your aircraft was made by the lowest bidder

Oops. James. I was the builder and if problems show up I know exactly who
to blame.
The 0.4 ips was given to me so long ago I don't remember the source. But as
I recall I thought it had to be gospel.
I do all the main rotor balance jobs in hover and the lateral 1/rev stays
good thru forward flight. The vertical only increases slightly at 90 mph.
However, with fuel tank less than 1/2, I get a lateral 2/rev that is above 2
ips. This 2/rev is from the main rotor as the 2/rev with the tail rotor
would be 92hz and very hard to feel. With full tank the main rotor 2/rev
goes away. Haven't been able to get to the cause yet so just keep the fuel
above 1/2. Believe that there is a resonance in the airframe somewhere
that likes the 2/rev frequency of 17hz.
I agree I couldn't tell the difference in feel from 0.1 ips to around 0.3.

BTW you have brought up something that has been confusing to me. I got a
ride in the Hummingbird which is a S-52 derivative and found myself after a
short period in smooth air feeling nauseous. I thought at first that I had
some food poisoning and aborted further flying. Later I thought that it
might have come from the blade flicker coming thru the eybrow windows. I've
never felt nausea in any helicopter before. I thought the Hummingbird was
pretty smooth, but maybe you've hit the cause of my nausea.

Stu
Rule #1 with amateur built ships the source of your problem is very close.