Hi all.
Is there anyone in the
group with a rotary
powered heli, or have an
ongoing helicopter
project using rotaries ?
Best regards.
BenSison
Lots. Unfortunately most of them probably failed because
the designer underestimated the rotary cooling
requirements.
A large fan mounted on the front of the e-shaft would be
called for and the engine derated for that power loss.
This was done well by Robinson.
The cooling air should be taken in at the very front and
exited
at the rear to take every possible advantage of the waste
heat.
Paul Lamar
I have a plan for putting a turbocharged two-rotor in a Rotorway. The
Rotorway is a good candidate because it's already liquid cooled and my
concept for the drive will simplify the transmission as well as get rid of
some weight. There are Rotorways available with blown engines for very
reasonable money. I just haven't had time to get to this project yet.
Steve Brazil
Steve,
Would you know what engine RotorWay is using. On their website is
essentially no information other than a number "RI
600N Engine". Do they use a Lyc or such?
Rolf
They build their own water cooled VW based horz opposed 4 cyl.
It was done about 30 years ago. Note where the exhaust pipes come
out of the heads.
I think they are a bit optimistic about the 137 HP.
They don't appear to be de-rating it from the cooling fan losses.
The cooling is nicely done however.
Paul Lamar
A slight word of caution about this if your goal is to mount the engine
vertically. A lot of my airport buddies worked for OMC (before it's
demise). OMC was actively perusing an outboard engine using a rotary.
Their results were quite exceptional in that it "smoked" the completion, and
my understanding was that it exceeded their hopes. However the project was
scrapped for two reasons. 1 oil slicks 2 Difficulty in lubrication of
bearings and seals due to the orientation of the engine-- probably the top
bearing and the tops of the seals.
#2 yielded, from my memory a very short lasting engine.
Rich
I think it is never a good idea to reorient the Mazda engine.
The rotor cooling depends on gravity to help the oil flow
in and out of the rotor. That is how the rotor is cooled.
The apex seal temperature depends on a cool rotor.
However this would not be a problem with silicon nitride apex
seals.
There were some Sachs charge cooled rotaries used in lawn mowers
where the rotor sat on the bottom housing apparently with out lube
problems. No side seals were used on that side of the rotor.
Not much HP per cubic inch however.
Paul Lamar
FWIW: I seemed to remember reading about rotary engines being used in
Russian helicopters but the details were fuzzy so I Googled it and found
these:
Russian firm builds 'helicopter for businessmen'
http://en.rian.ru/business/20110817/165852740.html
Kamov KA-56
http://www.aviastar.org/helicopters_eng/ka-56.php
Heli Air Design chooses Mistral G200 rotary engine for Helineo
http://helihub.com/2012/09/05/heli-air-design-choses-mistral-g200-rotary-engine-
for-helineo/
Regards,
Jack Hilditch
All,
The Rotorway engine is incapable of delivering the 150hp to the main rotor
that it was designed for and the Rotorway engine is doing good to last 250
hours. My design concept mounts the engine horizontally and eliminates the
primary drive; I only use secondary cog-belt drive to the rotor. I already
have a gear set picked out and a layout of the transmission. I think if I
used an all aluminum two-rotor, I would remove around 150 lbs. from the
aircraft.
The rotary is the only non-turbine engine I know of that is well suited to a
helicopter. Since the rotor must run at nearly constant speed, the engine
must be geared to run at probably 6000 rpm and the rotary is perfectly happy
doing that, provided it has cooling. I don't know what the recip is running
at but it must be close to the rpm where it makes rated horsepower, which is
very hard on it. The rotary can be operated just like a turbine where you
set rpm and hold with a governor and vary torque with the
governor-controlled throttle.
Steve Brazil
I like this final drive design. All of the rest of the drive shafts
are low torque and higher RPM so they come out much lighter.
It was very clever of the Mosquito designers to use this
design. IMHO it is the best designed small helio I have seen so far.
Are you going to use a tail rotor Steve?
Looks like the Notar is cheaper and lighter.
You need the big fan for cooling anyway.
Paul Lamar
I like the Mosquito too; actually, my drive concept ends up very similar to
the Mosquito. I'm going to use the stock tail rotor and drive because I
want to fly the thing, not prolong the project. The NOTAR would take a lot
of work to build and it isn't as efficient as a conventional tail rotor. I
want to focus on a solid, reliable drive train with no more variables than
necessary. If I were to do something with the tail rotor, I would probably
look at the fenestron but I think it would probably be more trouble than
it's worth. Rotorway came very close to building the perfect everyday,
affordable helo but they put an inadequate engine in it.
If it wasn't such a pain to do it, there are a plenty of type certificated
helos that need on the order of 200 horsepower and are designed for
horizontally mounted engines. The Hughes and the Enstrom, in particular.
You could build a short bobtail adapter for the Mazda that would incorporate
an approximately 2 to 1 reduction, centrifugal clutch and vibration
dampener. The unit could go right in place of the existing engine and use
the existing drive. The Enstrom would benefit hugely from this since they
are very hard on their engines.
Steve Brazil
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