Paul

  are you sure you want to use 7075??
  I have a great source for 7050 with certs cheap cheap cheap it's all
  boeing scrap.
  maore than you will ever use. My machine is not being used at the moment.
  I can machine the plates and squares
  if you send me the drawings.

  Tony

  I'll get back to you when I get back from check rides Tony.
  What dwg format can you use. We might try a built in planet
  carrier on the 4 inch aluminum shaft.

  Perhaps Ed needs something right at the moment?

  Paul Lamar


  This picture will give you a feel for the strength and robustness
  of this type of four inch diameter aluminum prop shaft  PSRU.


  Paul Lamar


  That looks like it otta handle it. The shafts on the 2.85 are 4.17", which
  leaves me with perhaps a .020 wall thickness; if I edm for 3/8 bolts. I
  could likely find 9mm bolts and end up with about .030". I don't know what
  the limit is for the lazer, or the minimum needed to provide a good
 surface
  for the pinion bearings to ride on.

  Ed Carver


 I have opened an order with Sunshine metals. Order pending receipt of in
 house credit app. and fund transfer. The base price for 28 inches of 4.25"
 7075 t73 round bar is $205, of which you want 14". Tax and shipping will be
 added to the end total.
 This company will not let me pick it up directly:(

 Ed Carver


 OK Ed I am in for half.

 Paul Lamar



 Paul,  As I understand it you are not incorperating provisions for a
hydraulic constant speed prop.  Just for those of us who would like this
feature, how might it be accomplished with a roller bearing supported
propshaft and a planetary gearset.

george grimes

It won't.
Check out Jeans gear box. IMHO CS is not needed for the majority of home
built's as they have such a high power to weight ratio take off is never
a problem. Unless of course you want to improve the MPG by slowing down.
Also those old Hyd CS are heavy at around 50 pounds not including the gov.

Paul Lamar

Ed, I am thinking we will need a 37 mm OD needle pilot bearing
on the inner end of the prop shaft for the sun gear.

I'll do a 3D shortly. That means we should drill the 2 inch holes
only six inches deep and not all the way through the 7 inch long
4 inch bar.

Since the sun gear and the prop shaft turn in the same direction
the pilot bearing will only see the difference in RPM
or about 4000 RPM max.

Something like this will work fine with an inner race.

Paul Lamar