AUTOGYRO Ela jump takeoff

[rdou]

https://www.instagram.com/reel/C53aDORI ... FmNXRyOA==

 

[kolibri282]

Great! This should give that gryo access to many places denied to those aircraft needing a ground run for takeoff and thus considerably increase the number and places of possible gyro usage. I had always wondered why nobody offers a gyro with that very desirable capability, as jump takeoff was demonstrated almost 100 years ago. I wonder though if it is legal in all countries, any information on that?

 

[scottessex]

Game Changer for sure, as long as it is not helicopter pricing.
Now you can get off that sand bar you were able to land on.

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[Aerofoam]

Or that White house lawn!!!!!

Sorry, couldn't resist that one.....

 

[scottessex]

That too!

 

[WaspAir]

I wonder though if it is legal in all countries, any information on that?

Perfectly legal in the U.S., but it would require a Recreational (or higher) certificate level gyroplane rating (Sport Pilot privileges will not suffice).

 

[MikeBoyette]

Or that White house lawn!!!!!

Sorry, couldn't resist that one.....

Wasn’t the White House, Doug landed on the capitol building lawn. If he had landed on the White House lawn he would have never survived. Since there are miningun torrents embedded in the lawn and anti aircraft missiles on the roof. Doug said the lack of such security is why he chose the capital. The other reason was to deliver his letters to each member of congress.

 

[WaspAir]

In 1994, Frank Corder (while drunk) flew a stolen Cessna 150 into the White House but didn't survive the crash. Nobody was home at the time.

 

[kolibri282]

Interestingly ELA announced the aircraft one year ago. There is a video from 04/23

ELA promo video

A German Flight Magazine published a picture of the rotor head. Of course they have installed a fairing, so that you can not really see, how the jump mechanism works...;-)
ELA rotor head

I wonder why people have not become interested earlier.

 

[wolfy]

I think people have just been sitting and waiting to see what happens, not a lot of media about it so far.

wolfy

 

[PJB]

won't be coming to the UK anytime soon but I wonder why the launch can't gain more height? Its obviously good for areas that limit the take off because the surface is degraded but doesn't seem to be of use in confined areas.

 

[XXavier]

It might be a mechanism working along the same principle as Cierva’s ‘autodynamic’ rotor head of the 1930s, an automatic pitch-changing device. While the rotor is being driven in pre-rotation, the blades are at very low pitch, giving little or no lift at all, but the moment the drive is disengaged, the blades automatically increase their pitch to the usual autorotation value of 2º– 3º, that may not be the best for high thrust, but would anyway work for the jump, provided the RRPMs are high enough…

This is an enlarged still from the promo video...

 

[WaspAir]

won't be coming to the UK anytime soon but I wonder why the launch can't gain more height? Its obviously good for areas that limit the take off because the surface is degraded but doesn't seem to be of use in confined areas.

Storing enough energy in the rotor for a high jump requires more mass spinning much faster than is customary.

For the A&S18A, to lift 1800 pounds reliably about 15 feet, the rotor carried 3 blades at 55 pounds each, pre-spun them to 150% of flight rpm, and suddenly popped in about 8° of pitch (with the pitch cut roughly in half as the blades slowed and coned).

 

[Eric S]

Respectable jump height with zero forward roll.

 

[kolibri282]

The whole physics of jump takeoff is explained in some depth in naca report 528. I had implemented the formulae some time ago so everyone who is interested in the topic can download the report and the program using the link below and play around with the variables a bit.

Jump Takeoff Program

 

[Doug Riley]

In particular, increasing collective pitch to only an autorotative value (2-3 deg.) is not at all efficient. In a jump takeoff, the rotor is (temporarily) a helicopter rotor. This means that the airflow into the rotor originates above the disk. This orientation of the flow reduces the angle of attack that the blades actually experience.

A typical airfoil is most efficient at an angle of attack (AOA) of about four degrees. The energy available for a jump is quite limited (to what you're able to store using the rotor as a flywheel). Therefore, we need to give the blades the most efficient AOA possible. The 8 degrees used in the A&S 18A allows for the influence of downward flow in diluting the actual AOA that the blades "see." IOW, from the blades' point of view, 8 deg. of mechanical pitch is more like 4 deg. of AOA.

2-3 degrees of pitch during the jump will not provide the kind of spectacular takeoffs we've seen in Dick DeGraw's machines and in the Cartercopter jump mechanism. That skimpy amount of pitch wouldn't work very well on a true helicopter either -- for the same reason.

 

[Abid]

In particular, increasing collective pitch to only an autorotative value (2-3 deg.) is not at all efficient. In a jump takeoff, the rotor is (temporarily) a helicopter rotor. This means that the airflow into the rotor originates above the disk. This orientation of the flow reduces the angle of attack that the blades actually experience.

A typical airfoil is most efficient at an angle of attack (AOA) of about four degrees. The energy available for a jump is quite limited (to what you're able to store using the rotor as a flywheel). Therefore, we need to give the blades the most efficient AOA possible. The 8 degrees used in the A&S 18A allows for the influence of downward flow in diluting the actual AOA that the blades "see." IOW, from the blades' point of view, 8 deg. of mechanical pitch is more like 4 deg. of AOA.

2-3 degrees of pitch during the jump will not provide the kind of spectacular takeoffs we've seen in Dick DeGraw's machines and in the Cartercopter jump mechanism. That skimpy amount of pitch wouldn't work very well on a true helicopter either -- for the same reason.

Dick Degrow’s machines were not gyroplanes. They were continuously partially powered rotors. Closer to half a helicopter than a gyroplane.

But I agree 2-3 degrees of pitch won’t do decent jump TO gyroplane.

 

[MikeBoyette]

WTF is a Nachobe? Weird way of calling the Rhino series a Mexican Jumping Bean? If so that is funny and I had no idea you had a twisted sense of humor like me.

 

[Abid]

WTF is a Nachobe? Weird way of calling the Rhino series a Mexican Jumping Bean? If so that is funny and I had no idea you had a twisted sense of humor like me.

Chill it was supposed to say machines. IPhone has its own brain sometimes I actually have no idea what Nachobe even is.

 

[Doug Riley]

Isn't Nachobe a kind of cheese dip? Or I might be mistaken...

Abid, I guess a half a helicopter is like a half-full glass of water... or half-empty. Fact is, by the time you add collective pitch, probably a controllable-pitch prop, a swashplate cyclic and a robust drive mechanism that allow for jumps, you've built more than half a helicopter -- even if you don't include Dick's in-flight rotor drive.

I imagine this is the unfortunate truth that sank the gorgeous (but unmarketable) Groen Bros Hawk IV. Just add a tail rotor and you get a fully hover-capable helo for about the same money.