Paul,
Any contra-rotating Mazda 13b 2 engine 4 total rotor (or 2 total
rotor) designs out their? I did like watching the
http://www.electro-flight.com/single-post/2016/07/20/Fully-Chargeds-Robert-LLewellyn-Documents-Electroflight
<http://www.electro-flight.com/single-post/2016/07/20/Fully-Chargeds-Robert-LLewellyn-Documents-Electroflight>
video demonstration of the output. Any truck transmission planetary gear
sets with contra-rotating outputs? Very likely would set the small
helicopter world on fire.
The Wankel Rotary would be a great application for contra-rotating
propellers, or small helicopter contra-rotating blades & flight control.
If a center line shaft from one engine could be made to pass through the
second e-shaft, connected to a gear hub for both propeller sets.
George F. Curtis Jr.
http://www.rotaryeng.net/VTOL.html
I don't really know if this is going to work. I have not built it yet.
Not only that some of my assumptions may be wrong so think about it.
-------------------------------------------------------------------------------------------------------------------
"This gear box is stunning in it's simplicity. Since we are
proposing using the A/C proved Ford eight pound A4OD six pinion
planetary in a differential mode the total gear reduction is 6.34:1. See
http://www.rotaryeng.net/psrus.html
<http://www.rotaryeng.net/psrus.html>. The ring gear is rotating in one
direction and the planet carrier is rotating in the other. As long as
both props have the same drag the RPM's of each prop will be equal. With
an engine RPM of 8000 the rotors will be turning 1262 RPM for take off.
I would use a 13 foot diameter rotor at this RPM."
"There is a possibility that the gear box could start up with both
blades rotating in the same direction. One blade would be going
backwards so that might be sufficient torque load difference to force
the unit into counter rotating mode."
"The over all diameter of this gear box is only about 6.5 to 7
inches. It should have it's own oil supply as it is on the very front of
the airplane and the engine is at the very rear for weight and balance
reasons. A simple mechanical pitch change design is used. The size of
the aft shaft is the same size as the ring gear. Namely five inches. A
simple butt weld is all we need. One of the results of this is the gear
case now becomes a simple piece of thick wall aluminum tubing about six
inches in diameter and eight or ten inches long. This will allow
increasing the diameter of the front shaft connected to the planet
carrier to four inches. A front shaft needs a lot of torsional and
bending stiffness as it is cantilevered a fair distance out of the gear
box."
"I would use plain bearings, oil filter and an oil cooler with a
dedicated high pressure stock Mazda 13B automatic transmission oil pump
driven off the input shaft. The remaining problem would be high speed
shaft seals."
--------------------------------------------------------------------------------------------
BTW this concept was conceived before we had a 200 pound turbo 2 rotor
putting out 650 HP making this project more than doable.
Paul Lamar
Paul,
If using a 13 foot diameter blade, could not the distance between front
and aft blades be shortened, "A front shaft needs a lot of torsional
and bending stiffness as it is cantilevered a fair distance out of the
gear box." as the 13 foot blades should not bend if a stiff material is
used? Attempt to reduce the cantilever some.
Next up question is if used as helicopter flight control, essentially
hanging / flying on a prop, where is my directional control coming from,
or perhaps I am not following your idea. Are you proposing this as just
a contra-rotating propeller unit? If so, perhaps reduction of the
diameter of the blades would be in order, 13 foot blades would almost
require design to follow the Vought V-173
https://www.youtube.com/watch?
v=LfpTDOAfj7Y
<https://www.youtube.com/watch?v=LfpTDOAfj7Y> flying
pancake,
https://www.youtube.com/watch?v=qeF1ppyFnfg .
The range of flight speed and take off speed by the Vought XF5U is
remarkable, even be more remarkable with flight control means of your
design to give it total VTOL flight control. almost match the Chinook
with twin rotors. Addition of the new TTC Mazda Rotary engine horsepower
offer some unheard of speed, range, reliability, and seating capacity
options.
https://en.wikipedia.org/wiki/Vought_XF5U Moving the engines
out to the ends of the wing, would open seating / cargo options on a
redesigned interior. Your VTOL concept crossed with the Vought Flying
Pancake would produce a stunning design.
George F. Curtis Jr.
I think one must allow room for blade flapping :-)
It is basically a weight shift situation. The thrust vector can be moved
around relative to the CG. Some of the pictures show a successful
helicopter that
uses that principle.
I think the main advantage of the high HP would be
the additional weight of fuel that could be lifted. The wing root would have
to be made thicker to accommodate the additional volume of fuel.
Of course the reduction in TTC engine weight will help greatly.
http://www.rotaryeng.net/VTOL.html
The modern solid state low cost gyros developed in the last few years
and widely used on low cost drones will help greatly in landing.
An auto landing system with ultrasonic height sensors will be essential.
Paul Lamar
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