Engine power for a ultralight

Aviator168

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Looks like the current engine is a Thor 250. 36hp. From the video, it looks flying very well. Don't know at what speed though.
 

Aviator168

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I checked out the Mosquito power plant. It seems the power requirement for a gyro is about the same as a helicopter in about the same weight. If you think of it, it kind of make sense. Both gyro and heli use the rotor to generate lift. While a heli uses the engine directly power the rotor whereas a gyro uses the air stream created by the forward motion push by the prop powered by the engine. Indirectly, a helicopter might be more efficient; however, it needs to deal with the torque created by the rotor and that energy is wasted. So, depending on how stream line and how efficient the pusher prop are, a gyro might just be a little more efficient than a helicopter. And in most cases, the helicopter comes out ahead. Another handicap for gyro is it can't takeoff vertically and hover.
 

PW_Plack

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I believe you can STATE the max airspeed in your aircraft operating manual. There is no requirement to demonstrate it. So, the entire issue may be moot.
Most builders of gyros this light in the US are hoping to operate them under FAR Part 103. There is no Pilot's Operating Handbook required in this case, but Part 103 requires documentation of a max speed of 55 knots in straight-&-level flight at max power, as well as compliance with other limitations, documentation which is supposed to be available on demand by an inspector.

§103.3 Inspection requirements.

(a) Any person operating an ultralight vehicle under this part shall, upon request, allow the Administrator, or his designee, to inspect the vehicle to determine the applicability of this part.

(b) The pilot or operator of an ultralight vehicle must, upon request of the Administrator, furnish satisfactory evidence that the vehicle is subject only to the provisions of this part.
 

Vance

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Video of original gyo. Crashed during takeoff. Don't what the engine is or the hp rating.
Here you have a good example of why training is so important even for an ultralight. Most of my clients could look at this and tell me what went wrong after their first hour of ground and all after their first takeoff.
In my opinion it has nothing to do with power or lack of it.
Gyroplanes don't kill pilots; pilots kill gyroplanes.
 
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WaspAir

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Indirectly, a helicopter might be more efficient; however, it needs to deal with the torque created by the rotor and that energy is wasted. So, depending on how stream line and how efficient the pusher prop are, a gyro might just be a little more efficient than a helicopter. And in most cases, the helicopter comes out ahead. Another handicap for gyro is it can't takeoff vertically and hover.
Many helicopters have a vertical tail fin of some sort, not just a tail rotor, and at a decent forward speed the airflow over that fin reduces the work that needs to be done by the tail rotor. In hover, of course, it can require lots of anti-torque pedal, but comparisons there aren't valid anyway because the gyro can't maintain a true hover as you observed. At speed, the tail rotor doesn't need to work as hard thanks to the fin, using less energy, and the relative efficiency of direct drive over fluid coupling for the main rotor wins the day.

Some gyros can manage a near-vertical jump take-off, but prop thrust means they actually are accelerating forward as they rise.
 

jany77

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The engine in the video looks like simonini mini 2 ,I have seen this ( first) gyroplane in another video or picture.
 

Aviator168

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In my opinion it has nothing to do with power or lack of it.
Yeah. The push prop torque is much more apparant in an ultralight, and even more so when the rotor is not loaded.


Gyroplanes don't kill pilots; pilots kill gyroplanes.
:LOL::ROFLMAO::love::LOL::ROFLMAO:🤣

The engine in the video looks like simonini mini 2 ,I have seen this ( first) gyroplane in another video or picture.
That engine only produce 28hp max. Might just be enough to power a fix wing UL. The new engine on that gyro is Thor 250 and it has 36hp. Guess 8hp makes a big difference. Then again, that's amost 29% more power.
 
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Jean Claude

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That engine only produce 28 hp max. Might just be enough to power a fix wing UL.
A FW can fly with much less power. My JCD03 of 175 lbs and span 23 feets was powered by a 12 hp SOLO engine and a propeller 28 inchs rotating at 5800 rpm.
But my calculations always gave more than 35 hp for a gyro.
img013.jpg
 
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XXavier

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A question: Is the additional power required by a gyro (in equivalent conditions of airspeed and weight) due to the higher parasitic drag of a rotor in comparison with that of a fixed wing?
Or are there other negative factors in the case of the gyro?
 

Jean Claude

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The rotor adds about 5 kW of profile drag, which requires a more powerful and heavier motor, which requires a more solid structure, and more fuel.
This additional weight now increases the induced drag which ... etc, etc. It's just a "snowball effect"

PS
Thank you for making me discover this Wikipedia' article that I did not know. Air Est Service mentioned never reproduced my JCD03.
They wanted to install a 20Hp engine without worrying about basic balances and the "snowball effect"
 

Doug Riley

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The lowest-powered Bensen-style gyros that I'm aware of use(d) 40 hp engines (Bensen started with the 40 hp Nelson; most of the rest of us in the U.S. have used ether an MZ or a Rotax 447).

Laminar flow appears not to be achievable in a rotor in the real world. An efficient non-laminar blade section is certainly better than an inefficient one, however. Flat-bottomed blades are easier to build than ones with curved bottoms, but the curved-bottom ones are slightly more efficient; maybe 5-8%. Excess trailing-edge reflex should be avoided, as it produces trim drag.

A Bensen-style airframe using bolted aluminum is not very weight-efficient. A set of bolts for a Bensen weighs about 10 lb. The metal components themselves must be thicker in the vicinity of the bolt holes to compensate for the weakening effect of the holes. Yet, we often use extrusions or drawn tubes which, by their nature, must have uniform wall thicknesses along their length -- so they are overweight in places where there are no holes.

A single-piece graphite-fiber fuselage for a Bensen-style gyro could weigh considerably less than the typical bolted product. It might well come in at only 200 lb -- but at great expense compared to our cheap bolted frames.
 

Aviator168

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A single-piece graphite-fiber fuselage for a Bensen-style gyro could weigh considerably less than the typical bolted product. It might well come in at only 200 lb -- but at great expense compared to our cheap bolted frames.
If you can save 50lb, the extra expenses is worth it. You can use a less powerful engine and get the same performance.
 

Doug Riley

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Maybe not 50. Ken Brock was able to pare his Bensen-style gyro down from the usual 260 or so to 225 while still using bolt-together extrusions. He used light go-kart wheels with aluminum axles and a light nosewheel fork, a lightened front boom, proprietary composite tail group, light rudder pedals, light blades, a wood prop, direct-drive fanless McCulloch engine, plastic seat tank, no prerotator and zero instruments.

How much lighter can one go using labor-intensive (and costly) graphite composite construction? Perhaps someone will do it and show us.
 

WaspAir

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A FW can fly with much less power. My JCD03 of 175 lbs and span 23 feets was powered by a 12 hp SOLO engine and a propeller 28 inchs rotating at 5800 rpm.
The Wright brothers claimed 12 hp for the 1903 Flyer.
 

Jean Claude

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The Wright brothers claimed 12 hp for the 1903 Flyer.
Certainly. And today, a 12 Hp engine weighs about 8 kg and it allows to takeoff in less than 300ft , rise at 600 ft/mn and flight 50 mph in cruise.
 

bryancobb

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Pertaining to the quest for building a very light yet strong gyro...

Helicopters have a minimum flight weight (minimum solo pilot weight) that's needed, not just for weight and balance, but also for the minimum potential energy needed to keep rotor RPM up during a forced, engine-out landing.

Doesn't a gyro have to obey that law of physics too? I'd hate to know I got a golden trophy for a 150# gyro with a 50 HP engine and then
when that 2-stroke dies one day at 2000 ft. I can't autorotate down because I don't weigh enough to keep the rotor going.
 
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