ddunbar wrote:
Paul I agree with all your comments.
I find hard to believe that a manufacture of aircraft equipment can
produce a PSRU being so heavy! We are all looking for a PSRU that can
handle the torque of a 13b at say 6500 rpm with an output of around 250hp
. There seems to be many manufactures willing to sell their brand of PSRU
to the home builder and they all seem to be over price except the unit
offered by Tracy Cook.
In the marine industry I can buy a marine reduction gear with a higher
duty cycle than an airplane with oil lube pump, reverse gear and cooling
for $1200.00US and weighting 35lbs.
Tracy Cooks unit looks to handle all we rotarians need and we should
all work with a supplier of equipment to achieve a competitive product
that we all can use and benefit from the results.
Don Dunbar
marc wiese wrote:
I for one diagree with Don's comments. I am having a discussion with EPI at
this time. Since I have a 20B and plan to turbo it I expect to get higher
hp (350hp) and torque (350'lbs as well) out of it. I also think we all
could benefit from a unit capable of cs operation, (none that fit the
rotary currently can do that-you have to use an electric prop to get that),
and perhaps capable of beta range operation and feathering (seaplanes and
high perf types). It would have to be fully tested for resonances with
METAL props (has anyone except Powersport even intimated that they would do
that?). I think there is a lot of room for improvement in such a piece of
important equipment that our butts are depending on. After all, once the
heaviest duty unit is done, it is easy to downgrade it rather than upgrade
it, no?
Marc
The Enginair unit is shipped with a Hoffman or MT wood blade
constant speed prop. I don't think they have tested it with
a metal constant speed prop. Very BIG difference. If all you
want is the constant speed prop why don't you buy the
electric version of the Hoffman or MT?
You are going to be on the cutting Edge marc. At least Tracy is
testing the six pinion planetary on a 13B as we speak.
What kind of plane are you building that you don't care about
35 extra pounds in the engine psru and a six inch prop shaft offset
from the rotary e-shaft center line? Not to mention of course
the 57 to 65 pound weight of a metal constant speed prop.
BTW don't you believe me about the length of the line contact
being proportional to the torque capacity of a gear set? :-)
The Enginair is about 1.5 inches long while the Ford six pinion
is 4.8 inches long. That is a huge difference with the overwhelming
advantage to the Ford planetary set. Am I not clear about this??
Paul Lamar
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