I have an idea for you Scott.
There is a water jet company in 1500 Airway Circle, New Smyrna Beach
FL. 32168 | 386-424-7333
<tel:(386)%20424-7333>
I have some drawings of a steel coupling that can be made out of
water jet cut steel parts.
Then you will need to find a local tig welder to weld it up.
I have some of the parts. The inner plate that bolts to the counter
weight and the outer ring cut from six inch tubing.
$50 plus mailing.
Use part of Tracy's torque isolator to adapt this to Tracy's PSRU
input shaft. Drill out the rivets and bolt it to the steel output
front plate.
Paul Lamar
Very interesting! I can query the water jet shop, and will order
these parts if the shop can make the rest. No problem with the
welder.
How thick is the metal?
Do you intend for an outer ring to be cut into the small curved
shapes, or make these from scratch? I guess they can be flat
instead of curved?
I also assume the 1.78” is the height of each component, so the total
thickness would be about 2”? I will study my redrive to look for
areas of potential interference.
Please ignore the curved questions of my last post, sorry. Some of
the latter images didn’t display the first time. I see the
connecting elements are square.
Thanks!
Scott Gettings
.050 to .150. Some of the stuff is .083. You make it out of what you
can find :-) The six inch tubing is about .150 wall.
The total thickness is about 1.8 inches. Nothing about this is
critical. One inches would work if your not shooting for 500 HP.
Ignore those square pictures. The latest are triangular or wedge
shaped. The square ones bottom out corner to corner. We discovered
that when we built the TTC coupling.
If I get a little more interest in this I wall make a tool that bends
the wedges in a hydraulic press. Saves a bit of welding. I have built
tools like that in the past. That would pay off as the same design
can be used in new gear boxes. We already used one of these that was
similar in a 3 rotor.
I have not heard back from Kevin so if Kevin finds an NC shop that
can make them out of billet at reasonable cost that would be more
accurate.
In any event once this is welded up it would be wise to balance it
between parallel bars. If your gear box is off the engine please tell
me the diameter of the input spline adapter Tracy is using. The one
with all the rivets. That will control the diameter of the forward
plate.
Paul Lamar
Paul,
My welder can assemble these small steel parts, but is not highly
confident of the precise alignment and balance of the end product. It
looks like some other options are evolving, so I’ll keep this one
on hold.
My gearbox is on the engine, but if you need the exact shaft diameter
soon, I will be happy to pull the it and measure the shaft.
Other measurements that might be helpful:
distance from front edge of flex plate gear to rear of engine block: 1
5/16”
distance from front of Tracy’s adapter plate to engine block (the total
“open” area between the engine and adapter): 3 1/8”
distance from front of Tracy’s adapter plate to rear face of his
riveted
spline adapter: 1 1/4”
the front of the spline adapter appears very close to the rear edge of
the flex plate ring gear.
It appears that the total thickness of a new coupler (for Tracy’s RD)
would need to be the exact distance from the rear face of the bolted
area of the flex plate to the rear of its ring gear, which is the plane
of the front of the riveted part of the spline adapter. This would
maintain the dimensions for the thrust bearings. A coupler that is
more
thick than this would move the rest of the RD to the rear, requiring
alteration of the existing spacers (the 3 1/8” distance). A thinner
coupler could be managed with thrust bearing washers.
Scott Gettings
I just happened to have one.
The OD of the part in question is 6.188. The long part that sticks away
from
the engine 1.158 long.
The idea is to turn it around and put the long part inside the
coupling.
We worked this out years ago :-) 3D's 5 and six show this config.
That Ford part raw weighs 3 pounds. There is unnecessary meat on
both sides that I can be cut off if you send me yours. That will
give you
plenty of room and save a bit of weight. Some of the spline part can be
cut off as well. 1.25 inches of spline would be plenty.
Jean is down the road from you in Pompano Beach and he might do
it for you. He has a lathe and a mill. He will need one sooner or
later :-)
Here are a few pictures.
Paul Lamar
/
Paul
There is a sketch showing what i do have in mind as water cutting
parts ans joint it together by tig welds
/ JEAN PRUDHOMME
Good work Jean. Did you do that on Rhino?
I don't know if the water jet people can cut aluminum that thick.
If so it saves a lot of tig welding.
Could also be done carefully on a band saw with a narrow blade.
The silicon rubber blocks could be only one inch high and that
would cut the over all thickness. That height would easily fit
Tracy's gear
box and adapter plate set up.
This would be the fourth way of doing it.
Paul Lamar
Paul,
While I respect the idea of a strong DIY attitude I often wonder if we
aren't making more work for ourselves with these couplings. I mentioned
that most motorcycle rear wheels have an almost identical drive between
their sprocket, (rear), and wheel hub. They already come with dampening
rubbers and shaft bearings should we want to integrate them into our
designs. Lots easier than a roll-your-own. Many of the large
displacement bikes are in the same horsepower ranges these days too.
Then there is the idea of using a coupling initially designed for a
shaft to plate coupling like the Lovejoy or Centaflex. You can get
either one with a splined center or slide-on bushings now easing
assembly considerably. There are compact couplings of up to 3000 Nm
capacity. A 500-1000 Nm version should work for us, and they have models
a light as 1 Kg. I have attached a screen shot of one of the LJ catalogs.
Bill Jepson
Yes but that design caused the crash of the Rotamax powered airplane.
The bolts are in cantilever bending and they fail at the root of the threads
due to the torsional vibration.
That is EXACTLY what we are trying to avoid here.
Paul Lamar
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