The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

Sunday, November 21, 2010

Fixed Pitch Blade Tracking

I noticed that my CB180Ds blades were not tracking properly. When looking at the rotor disk on edge I could see that the blades were taking two separate paths through the air. I read online that fixed pitch (FP) helis need their blades to track properly, just like CCPM helis. I also read that by putting a piece of white electrical tape on the end of one blade (small enough not to cause a gross imbalance) I could see which blade was tracking high, and which was tracking low. It really worked. I also read on this same link that placing a small piece of tape at the blade grip would change the blades pitch and bring the blades in line. I had to chose to either bring the high blade pitch down, or the low blade pitch up. I arbitrarily chose to bring the high blade down. I found I had to put a piece of tape in front of the bolt on top, and a piece behind the bolt on the bottom, tilting the blade forward reducing the pitch. This levered the blade so the leading edge pitched down. On spin up the tracking was spot on! (See this link on RC Airplane World:

http://www.rc-airplane-world.com/rotor-blade-tracking.html

Windy day, so I hovered the CB180D in the Man Cave for one pack. With the mixer set up for in flight as opposed to hover stabilty it was still easy to hover, but I couldn't take my eyes off it for second. Can't wait to see what happens when I can let her run. If it doesn't improve her handling in flight, I will bring them to the middle, balanced for hover and flight. (See this thread on the subject of bell mixer set up on HeliFreak:

http://www.helifreak.com/showthread.php?t=258027

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