Using a Rotax 912 on a single seat gyro, Pos...Cons?

Resasi

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There are a few single seat gyros that have used the bigger Rotax 912 engine. I have only seen two and heard of another.

Roy Davis’s single seat hot rod is a very small compact machine with a 912 that he does his amazing demo’s on. It’s rate and angle of climb quite amazing, but then Roy is an extremely experienced and capable pilot.

Over here in the UK I have seen Steve Hart’s 912 Merlin. I gather that the static thrust test on that was around 390lbs, and apparently, that was not the only one around.

Nicolas has put a 912 into a single seat Genesis but not much information on how that worked out, though I have no doubt is was done correctly and was safe to fly.

Why would one want to do that. In Roy’s case I would venture the increased performance that would give him, but there could possibly be other reasons though is is debatable whether these would be completely valid.

Operating from high altitude locations, or flying in areas where climbing over high terrain might be a regular thing. Also being a 4 stroke the decreased fuel consumption over the fairly thirsty two strokes could give greater range for single seat touring.

The problem being the trade off of the extra weight of the 912 and all it associated hardware against the useful load of pilot and fuel on the 582, the extra cost of the engine, and, the potential hazards the extra power might present to the pilot.

Not many have done, some have expressed an interest in doing it, was wondering if some of our more technically savvy Forum members might offer us some insights on the matter.
 

GyrOZprey

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The Butterfly Aurora is another single seat "high-performance" gyro that uses a 912 ULS (100hp) ...needed with the heavy G-force landing gear bringing the empty weight to 525# At high elevations / summer heat the 912 is a must for this gyro!
 

mark treidel

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My old single place Dominator had the 912ULS. It ran like a scalded rabbit here at runway level 5512'.
My hangar mate, Dr. Bill Clem built the 1st Dominator with a 914 on it and held the world altitude record of
over 24,000' for a few years until Ron Herons' little wing broke it at 27K. I would love to have that machine back.
The cruciform tail mitigated most of the 'P' factor but during take off at full power combined with a higher right crosswind, one had to
be mindful of strong 'torque roll' to the right. There were a few times I had to 'ease' off the throttle to compensate.
Otherwise I would feel like continued full throttle could possibly flip the gyro. Still though, very manageable. I would not
suggest this type of power for an inexperienced pilot. It was something you had to 'sneak up' on and develop a definite
feel for. Certainly glad for that power on high D/A days of summer. Most of the time it's well over 8K' here. A 582 on a gyro
at our altitude has to be 'stair-stepped' into the air. I fly a 914 turbo now and use every bit of it.
 

Hosko

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Gyroscopic Rotorcraft Broken Hill , Aus , uses 912uls on all his single seat mustering gyros . I also build single seat mustering gyros fitted with 912uls .....that's all the mustering pilots will use. Fuel burn is generally around 10lts/hr , one lightweight pilot averages 9ltrs/hr (his Rotor Ute machine has clocked up over 4000rhrs) , check Rotor Ute on FB....👍.
 

dinoa

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You could always use a 912UL rated at 80hp and no full power restriction.
 

GyroRon

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Reason you don't see many 912 engines on single place gyros is cost. The engines new are expensive. Not alot of people want to invest that much money into a single place gyro engine... Not when you can use a much cheaper 2 stroke engine or some kind of cheaper automotive conversion engine and still have respectful performance.

By the time you decide to budget in for a Rotax four stroke, you might as well just build a 2 seater.

I think that is why they are semi rare on single seaters.

You can find reasonably cheap deals now a days on used 80 to 100 HP rotax 912 engines. Especially the 80HP version. They would be a worthwhile powerplant to consider if building a new machine or repowering a older machine.
 

Vance

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I have not flown a gyroplane with too much power or too much reliability.

I fly around mountains and in strong, gusting winds.

I have found power helps in both those situations.

Every gyroplane I have flown had a throttle to manage the power.

I don’t recall a situation where I was required to use more power than I was comfortable with.
 

Resasi

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Thanks for the responses, two that I particularly liked.

You can find reasonably cheap deals now a days on used 80 to 100 HP rotax 912 engines. Especially the 80HP version. They would be a worthwhile powerplant to consider if building a new machine or repowering a older machine.
I have not flown a gyroplane with too much power or too much reliability.
I am looking at just such a scenario with the possibility of a friend upgrading his 912 to a 914. We haven’t discussed price however feel that this fulfils both of the above quotes from people I know, and feel qualified to give advice I would follow.

The principle objectives in my case, range, endurance, and power when needed. The 2 stroke single seaters do tend to suffer at high density alts and summer temps, and are often for a quick fun burn round the patch. It would be nice to have the range to go places and horses available for the occasional tight spot. Probably essential for mustering where all these apply.
 
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