You could use the RB aluminum end housings to get a 110 pound 2 rotor
long block. With 250 HP the thing will climb like a jet. Just watch
the Vne. Only problem is the RB end housings are about 15K. What is
the expense of building a one rotor that is still somewhat
experimental even compared to the 2 rotor, and you do not have the
vibration problem Richard described.

Dale Davies

Dale, the 750 is only rated for 140 hp by the designer. Also, a 250
hp engine would exclude the craft from the light sport category, a
major reason for the popularity of the design, no medical required
and easier to get the light sport ticket. The Zenith CH-801 would be
the choice if light sport isn't a criteria. C. Smith



There is no limit on engine power for an aircraft to be eligible as
light sport. If you can make a two-rotor engine with cooling and
propeller reduction unit under 200 pounds, I say go for it. The only
power limit for light sport is that the completed aircraft can't
exceed 120 kt at full power at sea level. You can assure this with
proper choice of carburetor or EFI.

David Josephson




There's also the option to set a maximum continuous RPM in the POH
at cruise as some LSAs have done.  If you choose to firewall them,
against the max RPM requirements in the POH, then you can bust the
120 kt limit in level flight but that is an unapproved operation.
There are some who feel that this is cheating but the practice is
approved by the authorities.

All aircraft have a Vne but you are free to bust that limit too if
you choose.  It's your butt that you're putting in the sling.  Ask
Jimmy Leeward about that, oh wait, you can't.  He found out about the
results of that violation the hard way.  It's sad that so many others
died to illustrate a lesson that was already learned by the death of
so many others before.

The LSA regulations do not set a maximum HP or climb performance. If
you have more power available than you can use continuously you are
free to apply said power in climb phase so long as you don't bust any
of the other velocity limits of the air frame you are flying.

Most common air cooled aircraft engine applications have a climb
power setting that is time limited to a few minutes lest one overheat
the poor little boing boing engine.  I've normally seen this referred
to as the climb power setting.  There's no reason why you can't use
all 250 HP that your rotary can make in the climb as long as you
throttle back to the maximum continuous RPM in cruise flight.

Weight and balance is more of a consideration than maximum
horsepower. Staying within the 1320 Lb max take off limit while still
having a usable payload will put a limit on how much engine you can
carry in an LSA.

Mark LaPierre

I can’t quote chapter and verse here but if you are a private pilot
you need an endorsement to fly high performance aircraft (200 hp or
more). Assuming the above is correct and you can have an LSA with
more than 200 hp as long as it meets the cruise restriction I still
find it difficult to believe that a Light Sport pilot could get a
high performance endorsement.  That’s something you might want to get
an official opinion on.  High performance and light sport seem
mutually exclusive to me and if I were to go by the spirit of the
Light Sport rule high performance is not included in it.  That
however is just my opinion and may be wrong.

Will Aldridge


Hey Will,

You are right about the sign off for high performance LSA.  A logbook
sign off is required for LSA that fly faster than 87 kt CAS.  No
horsepower restrictions are mentioned in the LSA rules, only CAS
limitations.

A log book sign off is also required for operation in airspace under
tower control, i.e. where a radio is required.

A rotary is the perfect engine for an LSA.  That's why my CH 650 is
going to have one.

 Mark LaPierre