RCU Forums - View Single Post - 1/2A THRUST-O-METER
View Single Post
Old 02-27-2004, 09:18 AM
  #25  
combatpigg
Senior Member
My Feedback: (3)
 
combatpigg's Avatar
 
Join Date: Nov 2003
Location: arlington, WA
Posts: 19,891
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 1/2A THRUST-O-METER

HI BRUCE,and MARSHALL! Bruce, your set up looks great! Placing the load spring next to the pivot point give you a nice, steady, jounce and bounce free indication, I'll bet.

Marshall, What I do is get a baseline measurement of the whole package, the engine mounted to the gondola, and enough weights tied on to bring the weight of the entire package up to 3/4 of what I figure it will do. My bob weights are 1/2" steel nuts, that have been weighed in advance. They weigh .6ozs each. I first tune each engine for max rpm, and needleability with head shims, the jump from 15% to 30% fuel usually takes one or two shims. The engine has to be able to hold it's position in a hover for 5 seconds before it gets credit for the effort. This test is of value to sport and 3D flyers, but isn't totally relevant to what the speed freaks need to know. They like the" in the air" testing because they unload those engines, and onboard speed recorders tell the whole story for them. whereas I am testing at max load the whole time. I have seen the thrust of electric motor/prop combos published before and thought it was high time to get some numbers on our powerplants. You can evaluate many different things this way quickly. I only burn an ounce of fuel or less to do these tests, and I spend more time searching for prop adapters than anything else[:@]!