Min.speed issue

bowns

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Canton.PRC
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tend to build a bensen type.gyrobee probably.
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over 1000hr in dream
Me a green hand in gyro field and tend to build a Benson type on my own,probably gyrobee,for its sustained good repu and simplicity.But I want my bee more characterized,say,much more slower in level flight.I read somewhere --"Sportcopter gyro" as i recalled--that the Min.speed can be as low as 5-10mph .Since I sense it a mentally threat to be fast in the air and less fun,I wanna focus on my project its Min.speed level fly stability.I thought goal could only be achieved within the ultralight but the Sportcopter "VORTEX" proves me wrong.So there should be something out there but what is the point?
My sincere appreciation to any help.
 
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landman

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Jun 11, 2004
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Hilo, Hawaii
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Barnett J4B
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200
min speed

min speed

I have always had a problem with the minimum speed issue. Even with the bensen glider staked out on a windy hill it took tropical force winds to get it to actually lift off the ground. Powerd flight was just a fantasy at less than 45 mph with a vw engine. With Vanec in his two place sportscopter we did not want to see less than 60 mph cruising around and landing approach was 65 mph. It takes a lot of wind to keep these things up. Joe Souza's two place Bandit was the same. With the helmet he supplid for training and the open machine, it took a little getting used to just to stand the wind pressure on my neck.

My guess is for safe flying. Light machines 45 mph. Heavier machines 65 mph and fast machines like the Barnett 75 mph. :eek:

Martin Oliver
 

PW_Plack

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Bowns, I'm fairly new to gyros, but from what I've seen so far, operating at the minimum speeds quoted by the manufacturers may be possible, but not desireable. If a Vortex really will fly at 5 MPH, it will demand every bit of your attention to keep out of trouble.

Martin, I got to fly Jim Vanek's current tandem trainer for about 40 minutes last weekend, and 40 MPH seems to be about where it becomes a real handful with two aboard, total weight about 1100 pounds. The thing has so much power you could probably fly it slower but, again, you wouldn't have fun doing it. Best glide speed at that weight is 48 MPH.
 

Doug Riley

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Bowns, some manufacturers state as "minimum speed" the airspeed the gyro has at the moment it flares for landing. This, of course, is not a true flight speed, only a momentary speed.

Any gyro can be brought to zero airspeed in the air. It will sink straight down vertically at over 1000 feet per minute, however.

The Gyrobee flies at least as slowly as any other gyro. It will leave the ground (but fly very poorly) at about 17 mph.

Low speed does not add safety to a gyro. Higher speeds are not dangerous in a stable gyro. A small gyro like the Gyrobee is easiest to handle and most efficient at between 40 and 50 mph. It is MORE difficult to control at speeds slower than this! It also requires MORE power to fly slowly. This, in turn, leaves less reserve power for maneuvering.
 

Udi

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The way I read "min airspeed" in a gyro is the minimum airspeed in which the gyro can sustain level flight. In this airspeed, the gyro is way-way behind the power curve, flying with full power straight and level. Any change in pitch (or power) results in losing altitude. The only way to recover from min airspeed flight is to lower then nose and trade altitude for airspeed. Flying at the minimum airspeed is safe, as long as you have enough altitude to recover.

20 MPH seems reasonable min airspeed for adequately powered gyros. 10 MPH may be possible with the hot rods. 5 MPH... I don't think so.

Udi
 

bowns

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Aug 8, 2004
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77
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Canton.PRC
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tend to build a bensen type.gyrobee probably.
Total Flight Time
over 1000hr in dream
This is where i got the info from:
http://www.sportcopter.com/pages/vortex.htm

i think min.speed means a lot to ordinary people like me.People with little aviation experience do sense high altitude and fast speed threats to their security-- though
radically wrong in view of aviation control technic.What i really mean is,min. speed is not just a criterion judging light or heavy weigh of the machine, or good out of bad of its flight capacity,we do need a slower speed in practical gyro applications and this won't make the dubious so-call "low efficiency" any worse.Secondly,i noticed that more and more common people are charmed by this aircraft and make themselves potential newbies,and i wonder if you genius and vendors can give us a foolproof flying
machine.This might be a daydream new concept but i wish i didn't talk nonsense.
 

Udi

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What I think you need, Tinlum, is the most simple and light gyroplane that can be made. A Bee would be a good choice, but there are other good, light designs like the Ultra White Dominator.

To fly slowly you want to have a large rotor. A too-large rotor, however, would make your gyro bouncy in unstable air. If you are going to fly only in calm days with little thermal activity, you can size your rotor with a disc loading of 1 lb/sqft. A gyro with a low disc loading can fly more slowly with less power. Going for a disc loading of less than 1 is not recommended.

With regard to safety, gyros have the potential to be far safer than fixed wing aircraft if designed, built, and flown properly. Build one of the proven designs and get good training, don't fly out of your limits, and you will be very safe.

Udi
 

joeheli

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Mar 4, 2004
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Jacksonville
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Bensen B8M with Mac 90
Bowns,Like Udi just said. If you want to float on the air, the trick is bigger rotor blades. But is going to be harder for your engine too (More drag that the engine has to push).You will hear the engine screaming on high speed :eek: .

Other thing is that the blades that he is using on the video are 25' Mccutchen. Does blade has alote of enegy (inertia) that will help alote for does manuvers,in adittion to his 582 rotax,that will helps even more ;) .

Wind speed, if you can heard on the sportcopter video you will heard the strong wind. Strong wind in convination of 25' rotorblade and a 582 rotax, will make a any gyro to float. That is why he can hover, and back up the gyro like a heli. I heard that he use different configuration on blade for the video. I think was 23' for high speed manuvers and loop, and 25' for hovering and backing up manuvers :rolleyes: .

But,I take my hat and honor him.That guy is crazy doing a "LOOP :eek: ".
 
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Udi

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joeheli said:
Bowns,Like Udi just said. If you want to float on the air, the trick is bigger rotor blades. But is going to be harder for your engine too (More drag that the engine has to push).You will hear the engine screaming on high speed :eek: ...

Jose - at a low airspeed, a larger rotor has less drag than a smaller rotor. That's why the Bees use a large rotor and a small engine!

Rotor drag is actually a reverse function of airspeed, with the lowest drag happening at around 90 MPH. Conversely, the airframe drag is a direct (although non linear) function of airspeed. Airframe drag is lowest at.... zero airspeed, but the rotor drag is highest at zero airspeed. If you want less drag at low airspeeds, get a larger rotor.

Udi
 
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