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Engine basics => Engine set up tips => Topic started by: Jack Mulinix on July 23, 2011, 09:24:36 AM

Title: Hot spinner
Post by: Jack Mulinix on July 23, 2011, 09:24:36 AM
So was running my 46la last night and ran a tank full (4oz) and noticed that the spinner was HOT after. It is aluminium. I had never noticed this before on other engines. It seemed to run OK It has a R.S. needle valve and backplate and it was the first run with the new parts. Is this normal? or do I need to check for? Thanks  Jack
Title: Re: Hot spinner
Post by: Brett Buck on July 23, 2011, 10:42:36 AM
So was running my 46la last night and ran a tank full (4oz) and noticed that the spinner was HOT after. It is aluminium. I had never noticed this before on other engines. It seemed to run OK It has a R.S. needle valve and backplate and it was the first run with the new parts. Is this normal? or do I need to check for? Thanks  Jack

  It's not that unusual. It is usually hotter a few minutes after a run than it is while it's running or immediately after since the heat soaks back. But there is a lot of power being dissipated in the plain bearing and that heat has to go somewhere. It may be too tight or you may be using more or thicker oil than necessary, but as long as it runs OK I wouldn't worry about it.

    On my first ever 40VF flight, we flew the thing, and it was great. We marvelled over how loose the engine was after it quit and right after the flight, and how flippy it was (compared to crappy stone age ST46s). Spinner was cool to the touch. Fueled it up for the next flight, started to choke it, and touched the spinner and damn near burned the skin off my hand.

     Brett
Title: Re: Hot spinner
Post by: Jack Mulinix on July 23, 2011, 10:54:17 AM
Thanks Brett, was hoping all was normal.Just might have to take the pathfinder out for maiden flight. Again, thanks. Jack
Title: Re: Hot spinner
Post by: Steve Helmick on July 25, 2011, 09:04:48 PM
Is it possible that the spinner backplate is rubbing on the plane a little?  ??? Steve
Title: Re: Hot spinner
Post by: Jack Mulinix on July 26, 2011, 08:10:32 AM
Hi Steve, no rubbing, got a 1/16th all around. Ran again last night and all seemed good now. Spinner not as hot as initial run. also took away muff pressure and ran good  Jack
Title: Re: Hot spinner
Post by: Tim Wescott on July 26, 2011, 11:11:08 AM
As the plane nears Mach 3, the friction of air will make it hot too.
Don't neglect the motion of the spinner itself, Ty -- the plane doesn't have to go quite that fast if the spinner is making up the rest!
Title: Re: Hot spinner
Post by: Peter Nevai on July 26, 2011, 01:13:39 PM
Naw you got it all wrong. It's the centrifugal force as the spinner spins. Forcing all of the metal molecules outward like a centrifuge on steroids. Which is exaggerated by the continual 4 2 break of the engine speeding up and slowing down causing the dreaded umbrella effect as well. The effective rotational speed of the spinner is secondary and is of minor influence.
Title: Re: Hot spinner
Post by: Steve Helmick on July 26, 2011, 03:22:57 PM
Next, you guys are gonna blame Jack's spinner for Global Warming.  %^ Steve