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
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