Jesse Hilton wrote:
I just found this site today. I am building a Cozy IV
and plan on using a 600 hp 20b. I would like a
sustained 400 hp cruise at altitude. I am very
interested in your compound turbine ideas. How far
along is this?
What psru would you recomend? I have heard of
Geschwender, Ross and Barnett amoung others.
There is a company in New Zealand that produces 20b
aircraft engines rated up to 900hp. Do you know
anything about them? Their contact info on the web:
Rotary Engine Power, New Zealand
Contact: Grant S. Nicholls, 12 Aristoy Close, Conifer
Grove, Takanini, Auckland, New Zealand
Ph / Fax 64-9-2988848
E-Mail Address 105654.1753@compuserve.com or
gnicholls@compuserve.com
They also make aluminum housings that replace the cast
iron housings between rotors.
Any input would be appreciated.
Jesse
I don't know of any PSRU's that will accept 600 HP. Maybe they may
last a
short while for air racing purposes. You will probably have to
build
your own. Possibly out of Allison truck auto transmission planetary
gear
sets.
Also make sure you are using 3 mm wide steel apex seals. Check with
Dave
Lemon
at Mazdatrix for his experience with Mazda apex end seals. I think
he has
some
developed that will tolerate detonation.
We have a guy in Perth working on a 1500 HP three rotor turbo
compound
engine on here.
I am sure he will upload info as it becomes available. He is using a
turbine from
an R3350 TC engine. A bit overkill and probably too heavy for your
purposes.
You may have to find a large truck turbo and adapt it to turbo
compound.
You will also have to design and build a high input RPM gear box for
the
truck turbo turbine power take off. I recommend starting with a very
small
pinion gear and large planetary and ring gears. Similar to the gear
boxes
found
in airliner APU's.
A very ambitious and costly project all in all.
Paul Lamar
Hi Jesse,
to add to the above:
Mistral Engines from Switzerland is planning on 3-rotor engines
300 hp NA
360 hp turbo-intercooled
planned TBO is 3000 hrs
Cozy IV sounds like going places, not racing.
I suggest you go for 360hp cruise and 420hp 5min - take off maximum.
At that
power level, when things start to go apart it, it normally gets rather
violent.
IF your engine stays together over some 1600 hrs, THEN start to push
things
little by little.
With 600 hp on a Cozy IV you probably go Mach 1.0+ !!! :))
I don't know of anyone who ever installed 600hp in a Cozy IV, nor did
I ever
find anyone how was able to put a 600 hp 20b together and KEEP it
together
in an airplane! .....stand to be corrected!
If these guys claim that kind of power, what history to they have?
(This sounds like the Crossflow/Eggenfellner comparrison on the Subaru
engines. Eggenfellner would be stupid not to get the same power as
Crossflow, IF the engines stayed together! I think Eggenfellner is
just
about there where he can guarantee his claimed times. Crossflows never
made
it that far).
Thomas J.
If turbo compound Jesse is only talking 500 HP on the core engine. The
turbo compound
feature adds the additional 100 HP. The same situation applied to the
R3350. Without
the three blow down turbines it was rated at 2800 HP. With the turbines
it was rated
at 3800 HP.
I have no doubt the 3 rotor engine will live at 500 HP if properly
cooled. Jim Mederer
has well over 200 hours on a 900 HP turbo three rotor on the dyno with
ceramic apex seals.
Currently he is getting up to 1200 HP but not with a lot of hours so
far.
You can't compare a rotary with a piston engine. The piston engine has a
much much
steeper failure mode with increases in HP. Particularly an automotive
piston engine
like the Subaru. An air cooled aircraft piston engine is pretty much on
the limit from
the get go. Every part is closely designed to live at the rated power
and no more.
Something as small as a tiny nick in the crankshaft can cause
catastrophic hand grenade
type failure in just a few hours of use. The exhaust valves WILL fail
RIGHT NOW if
not properly leaned or richened at all times. The design is done this
way to minimize
the weight. For a heavy duty engine the current air cooled aircraft
engine is remarkable.
The same duty cycle in an over the road tractor trailer diesel truck
engine would
weigh close to 2000 pounds.
Paul Lamar
I read you Paul,
but, to aim at 500-600 hp at this stage for an engine that is supposed to go
into a cruiser is a little of the scale for me. If it is a racer, be my
guest, there are no limits.
I just believe it is unrealistic to think about that kind of power at this
level of experience with rotaries in aircraft. 900 hp for 200 hours on a
dyno is NOT the same as for 1000-3000 hrs in a plane. Dyno time always
implies changes, reconfigurations, etc.
I am not advocating the Subaru (though it is a really good engine ....for a
piston engine), actually since I got cought in the ACRE-web, I am convinced
the future of aircraft propulsion will be with rotaries and turbines -
"piston, thank you and good by!
BUT it is the same relation between Crossflow and Eggenfellner with claimed
power and TBO levels as I am afraid it is with this New Zealand company and
their engines. 300hp is a very unrealistic power level for a Subaru
based AC-engine. Just because Subaru runs some Rally cars at this level....
Aircraft power plants and race car power plants may have the same roots
and/or pricipals, but there it splits. Once in their respective frames they
are completely different animals.
Not that I would not like to see a powerplant with that performance, I just
never heard of or saw any in an aircraft. ONE engine related accident can
damage the whole movement immensly. So all I suggest is, to stay on the
ground when it comes to reality, and keep "flying" with dreams in race cars.
Obviously Jesse stumbled on this site today, so he was not following this
movement for long.
I believe it is important to point out, that one cannot take everything
straight over from car racing.
I don't know any race class, where you even COULD maintain such power levels
for such long times like in an aircraft - even a Reno Racer, what is it, up
to 15 min at max power ?!! What car race class can hold it that long before
running out of track and crashing into something. The Mulsanne straight in
LeMans was about 2 min BEFORE they put the curves in there. In Bonneville you
also will run of track way before that (if you don't, what are you doing
there? :)) )
Even in Offshore boat racing the engines get throttled constantly. It would
be interesting how long Rotaries last in that environment - Offshore. Any
one in that business with Rotary Engines?
Thomas J.
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