View Single Post
Old 09-22-2008, 02:31 PM
  #79  
mred
Super Contributor
 
mred's Avatar
 
Join Date: Jan 2008
Location: Glenwood, GA
Posts: 1,025
Default

Originally Posted by BEC View Post
mred - your racer case is where we should see more unloading once the airplane is flying well. That it's glow powered magnifies the effect assuming you set the needle a bit rich before takeoff so that when the unloading happened the mixture leaned out to "just right". Electric motors ARE different - their RPM/torque curves are very different from an IC engine.

That may be true to some extent with the engine speeding up because of the mixture changing to some extent after take off, but most of the increase is due to the prop unloading. I have heard the difference in sound from a prop standing still and one that is increasing in rpm while taking off and flying. It's not just Racers that do it either. My pattern planes do the same thing and they are not running high pitch props.

Now voltage sag is nice to think about, but it would be just backwards would it not? After the prop unloads, the voltage would increase, not decrease. The load on the battery is less after the prop unloads, so should not the voltage go up and not down like under load? As soon as I get my Eagle Tree I'll run some tests and see just what is going on, but until then I have nothing to prove my point that you can look at. Later.
Ed
mred is offline  
 
Page generated in 0.04299 seconds with 8 queries