×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Optimal coaxial spacing between rotors

Optimal coaxial spacing between rotors

Optimal coaxial spacing between rotors

(OP)
I need a simple method of determining the optimal vertical spacing between the upper and lower rotors of a fixed pitch coaxial system. What is the most efficient angle of pitch (incidence?) for fixed blades?

RE: Optimal coaxial spacing between rotors

Skytrek

The greater the vertical gap, within reason, the greater the efficiency.  The greater the pitch, within reason, the greater the efficiency.

A couple of homebuilt coaxials have fixed pitch, but IMHO, the rotor gap is going to be 'zero' a few seconds after a loss of power.

One small improvement over fixed pitch is to have a very simple 2-position pitch. Engine torque puts the setting at the upper limit [+/- 9-degrees] and lack of torque (autorotation) puts the pitch at its lower limit [+/- 1-degree].

For a slightly more sophisticated rotor RPM thrust control, you might consider. http://www.unicopter.com/0575.html

Dave Jackson

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources