YS 140L tuning questions

[David Harmon]

Iv'e always used the 814A with the 140L....dang, perhaps I have been
using the wrong one all along....duuuhh
I doubt that TT would make an adapter that required the prop to be
reamed so I think I would call them and see what they say.
Previously, I never knew the correct TT part number and the 814A is what
Central sent out....hmmm....
 
Remember, the prop hub thickness must be considered too.
The APC 16x12 hub is a little over 3/4 thick.
The APC 15.5x12 hub is about 11/16 thick...
 
If the adaptor nut tapped face contacts the inside of the spinner bolt
hole, the cone flange MAY not be inserted into the backplate slot even
though the spinner bolt is tight.
On the other hand, if the adapter nut tapped face does NOT contact the
inside of the spinner bolt hole, the cone will distort the backplate as
the bolt is tightened.
 
My problems have never been the length of the engine shaft, only the
prop hub thickness and adaptor nut length.
 
Dave

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On Behalf Of Ihncheol Park
Sent: Sunday, June 01, 2003 9:26 PM
To: discussion at nsrca.org
Subject: RE: YS 140L tuning questions



http://www.truturn.com/cgi-bin/store/agora.cgi?exact_match=on
<http://www.truturn.com/cgi-bin/store/agora.cgi?exact_match=on&p_id=tt08
14a&ppinc=adapt> &p_id=tt0814a&ppinc=adapt
 
http://www.truturn.com/cgi-bin/store/agora.cgi?exact_match=on
<http://www.truturn.com/cgi-bin/store/agora.cgi?exact_match=on&p_id=tt08
13a&ppinc=adapt> &p_id=tt0813a&ppinc=adapt
 
The 814A is for 63/91/120s because of the short end nut.
The 813A is for 140s with long shaft although it shows as short shaft.
The outside nut is pretty long and the inside one looks to be through
the prop.  So, it looks like I need to bore the prop with larger OD of
813A nut. (probably 11mm)
 
Am I right?
 
Ihncheol

-----Original Message-----
From: discussion-request at nsrca.org
[mailto:discussion-request at nsrca.org]On Behalf Of David Harmon
Sent: Sunday, June 01, 2003 8:28 PM
To: discussion at nsrca.org
Subject: RE: YS 140L tuning questions


Those numbers are TT adapter nuts. The APC props have different hub
thickness depending on what size prop you are using. Some TT spinners
will not fully engage the backplate if the prop hub is too
thick....other TT spinners when tightened will distort the spinner
backplate.
You can add washer shims in front of the adapter nut to prevent the
distorting and shorten the adaptor nut if the spinner will not go on all
the way. It's kinda goofy but that seems to be the way it is. I asked a
few other flyers about this problem a few years back but they didn't
seem to know what I was talking about.
TT may make a short and long adaptor nut....but I couldn't find it on
their website.
 
Dave

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On Behalf Of jim ivey
Sent: Sunday, June 01, 2003 8:00 PM
To: discussion
Subject: Re: YS 140L tuning questions


 lhncheol
You may have the wrong threaded adapter nut. Check that out. I'm not
familiar with 813A, or 814A. What are these numbers. Been a while since
I bought adapters.
 My 140l's run at full throttle about 1 1/4 to 1 1/3 needle opening.
That has a lot to do with nitro content. I run 30% heli fuel. I'm
guessing 2 turns out is a good starting place.
 
Jim Ivey

 

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