Is there any reason why the particular gear ratio between the rotor and
the
 output shaft (not sure if this is the proper term) was chosen?  Would
there
 be a way to modify this so that the PSRU was essentially integrated into
 the
 motor?  So, for example, so that 4 turns of the rotor were necessary for
 one
 turn of the shaft instead of 2?

 Just a thought, but might save alot of weight and one of the major risk
 factors of auto conversions.

 Thanks,
 Brannon

 I am not sure what you mean by "integrated".
 Can you come up with a sketch?

 Paul Lamar


 Brannon,   The PSRU ratio ideally is the engine RPM at max power for take
 off devided by the RPM where the prop tips are going supersonic. The next
 factor is that in our case we don't particularly want the added weight of
 offsetting the thrust line above the E-shaft center. The planetary gear
 arrangement puts the output shaft directly in line with the e_shaft with
 the
 added benefit of driving through 6 planet gears for a minimum of 6 teeth
 transmitting the power rather than one tooth on a gear to gear drive.
There
 is also a lot  of cumulative line contact on the gears with the planetary,
 therefore a relatively small gearset can be used. The gearset of choice is
 from Real World Solutions designed by Tracy Crook. This PSRU uses
 a superduty ford diesel (E40D) low range planetary which happens to be
2.85
 ratio  when the ring gear is held and the planetary drives the prop
Holding
 the ring gear also turns the prop the same direction as the engine rather
 than reversing the rotation allowing a larger selection of props to use..
 Ideally  we could use more gearing in the range of 3.20 to 1   but to use
 mass produced gearsets we have to choose something commonly available.  In
 my case (6 Rotor) I need a larger gearbox for 700 HP and after looking at
 photographs of planetary gearsets for sale on E-bay I chose the 4 wheel
 drive transfer case planetary from the same superduty Ford F350
 transmission. The ratio is 2.64 to one. More gear would be better,
however,
 this gearset needs no machining off of extra parts  and is well supported
 with bearings. It is also 4 pounds heavier than the E40D but I  can't
 compare the weight of something not strong enough with something that is
 overkill. This planetary is only used when the 4-wheel drive is in low
lock
 so even used there are very few hours of operation on the parts. I bought
 my
 set for $45 and it looks like new. I entered all the Ford parts in Rhino4
 last weekend and am designing the housing next weekend. I still don't have
 the shaft mounted oil pump that fits around the input shaft in the truck
 which I will use for pressure lubrication after running the oil through a
 cooler. This will allow useing gear lube in the PSRU rather than engine
 oil.
 I well attempt to attach a JPEG image of the Rhino4 drawing showing the
 Ford
 parts and the thin wall prop shaft designed to use this gearset. All drive
 is thru splines including one that has to be cut near the end of the
 propshaft The rest of the splines are used as is..The JPEG named geartrane
 shows the Ford parts which are used as they come out of the truck. The
JPEG
 named PSRU componets includes the propshaft as well as the parts assembled
 for use. In both images there are two lineups of the parts showing the
view
 from both ends.


 george grimes


George,

I wonder what propeller you plan to use.  Avia?  In order to get 700hp
from a 6 rotor, it seems that you'll need to run the engine at upwards
of 6000 rpm (naturally aspirated).  That will make your prop RPM
around 2300+.  An engine of similar horsepower is the PW R1340.  Most
of those are direct drive - like mounted on the old T6 Texan (SNJ),
and are generally rated at 2200 RPM.  In that application, the two
bladed prop is terribly noisy at takeoff (full) RPM, certainly losing
some efficiency.  I understand that they are 108" diameter.  A 3
bladed prop of smaller diameter will help..  Being able to turn the
prop slower would be even better.


Regards,

Matt-

I would not put too much credence to a six rotor. The output shaft on
the last rotor is not getting any larger. My guess is 5 rotors is pushing
it.
Emon Hurley built one years ago.

Paul Lamar


Matt,     The  prop is a 4 blade constant speed 72" diameter as used on a
700 HP turbo prop. The Lanceair (now Cessna) evolution uses this prop.  I
don't need to turn the prop past 2200  in the simulator I fly the airframe
in.  As far as the output shaft goes it is a matter of torque. The
transmission input shaft on a 400 HP diesel truck is smaller than the Mazda
rear stationary gear bore and it runs at 1200 pound feet. I have designed a
coupling to connect the two e-shafts that allows whatever accelerations the
shafts produce  without being rigidly  connected. The coupling is 98%
efficient with most of the 2% remaining as heat loss. A similar coupling
connects the PSRU . The PSRU shafts and planetary carrier use splines at all
connections which may dampen prop resonance slightly.

    In  X-plane the airframe cruises at 134 knots on  140 HP and after 500
HP (352 knots) there is a rapidly diminishing return speedwise and fuel flow
is going up  past 47 GPH. I am still trying different airfoils and areas on
the control canard to improve landing flare at a lower speed. With 82
configurations it is still a work in progress. Pitch stability on a 3
surface airframe is definitely a challenge and I have asked an aero engineer
in Fla for help with it. Sometimes I think an aircraft configured like a
Piaggio 180 can't be forced to handle like an RV. Jean Prudomme is intending
something similar and hopefully he has a plan I can emulate.

          While I have designed around a 6 rotor configuration I may build
it with 5. There would be 3 on the flywheel end and two on the accesory end.
I need a 3 rotor type shaft extension to increase the accessory end diameter
on the front e-shaft so there is no good reason not to make it a 3 rotor in
the process

     I set up the CNC machine  around lunch time and it runs 16 or so hours
at night on the engine patterns. It takes two such days for each layer, one
per side, and each housing averages four layers. There is a wear plate
section and a back section for each housing for a total of 92  parts to cut.
On part 23    I smoked the power supply on the PC and lost two weeks. All
the electronics are now in air conditioning with 2 surge protectors power
conditioning  and a battery backup. In the morning it is clean and
lubricate  the machine and finish part 24.

george