> > > > Jerry Hey wrote:

 > > > >
 > > > > Paul, I completed the deflection tests.   The MMP deflected .174"
 > > > > measured at  24 inches.   Tracy's adaptor plate deflected
.137 inches
 > > > > measured at 24 inches.  I'm dying to find out what this signifies.
 > > > >
 > > > > You need not worry about the test stand deflecting at all.  It was
 > > > > very rigid and heavily braced.   The steel plate is .375
thick with a
 > > > > piece of 3" channel  as stiffener from top to bottom.  This was tied
 > > > > into the stand frame and welded to the 3" plate.  During the test we
 > > > > kept bubble levels on the stand and saw no movement.   The two foot
 > > > > tube is 4.188 o.d.  Wall thickness is .188"
 > > > >
 > > > > Jerry

 > > > Excellent work Jerry. Thanks a bunch.
 > > > This is 600 ft pounds of torque applied to the motor plate
 > > > and 300 pounds of shear load applied to the 10 mm bolts and
 > > > 3.050 long 1/2 inch thick spacers. 600 ft pounds is the gyroscopic
 > > > torque you would get from a metal prop rotating at 2500 RPM and
 > > > pitching at 60 degrees per second. A worst case scenario
 > > > as we mostly run wood or carbon fiber props.
 > > >
 > > > That includes the deflection in the two foot long,   4" dia.
188 wall,
 > > > steel pipe, the steel flange and the 10 mm bolts and spacers. Not bad.
 > > > .174 in 24 inches is only an angle of .44 degrees. So Tracy's stock
 > > > plate deflected about .42 degrees or so. Hardly any
difference. I think
 > > > if we tested his super light weight plate version it would probably
 > > > deflect more than our pocketed plate.
 > > >
 > > > I here bye sign it off for production :-)
 > > >
 > > > You might unload the 300 pounds  and put the dial indicator under
 > > > the plate and reload the weight to see how much the 10 mm bolts and
 > > > spacer are deflecting due to the 300 pound shear load. We will need
 > > > to do that to prove to Tracy that our spool and our 360 degree 1/4"
 > > > plate spacer scheme is as stiff as his 1/2 plate spacers.
 > > >

 > > > > Paul Lamar

RE the 360 degree spacer plate:   I think I can do it with .125 thick
aluminum but I don't have anyway to roll .250.   Also, putting .250
over the .750 spools exceeds the outer edge of the bell housing.
Half of the wrap around plate would not be touching the bell housing.
If  the .250 plate was rolled and then cut into sections it could be
welded to the spools  and lined up with the bell housing.   But what
a pain!  Far better would be a cast spacer.   I think the pocketed
plate together with a cast spacer would prove to be the ideal
combination.   I like it better than casting the entire mmp.  because
it allows us to customize the Barry mount locations and it  is a
simple shape to cast.   It should  very reasonable.     Jerry

0.125 is fine if we go most of the way around.

Do you want to take a stab at making a casting pattern?
You will need a draft of 1/64th per inch. Shrinkage for
aluminum is 1/4 inch per foot.

A good heavy duty pattern could be welded up out of tapered
spools and tapered and curved 3/16 plate segments  as that is about
the thinnest that can be cast. Don't forget to make it
a bit over sizes for shrinkage. 

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site. Copyright 1998-2002 All world wide rights reserved.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org