Gyro Questions

[Guest Howard Hughes]

I must admit, I don't know much about gyros apart from the bare basics, but I am quite interested in Gyros and their capabilities. From my research I keep coming across the terms 'high thrust line', 'low thrust line' and 'centre thrust line'. Could somebody please explain these terms in detail, in particular which is most preferable in a gyro?

 

Also how do these terms relate to the following craft:

 

Xenon Gyros

 

Magni Gyros (in particular M-24)

 

MTO Sport

 

Sportcopter

 

Cheers, HH.:thumb_up:

 

PS: More questions to follow I'm sure!

 

 

[Guest Howard Hughes]

Already thought of another one...

 

When watching videos of gyros taking off, many seem to rotate until the tail strikes the ground, is this normal? If it is normal, wouldn't these continual tail strikes weaken the tail structure?

 

 

[winsor68]

I too am fascinated by Gyros... the only down side is everytime I have seen one being flown the hair on my head stands on end!!! So exciting but scary even thought the logical part of my brain tells me that they should be one of the safest flying machines.

 

I have wondered about the tail thing myself... if it doesn't hit the ground on takeoff it often certainly does on a slow landing... are there any Gyro flyers that can enlighten us?

 

 

[bruce01]

There is a wealth of information here. www.asra.org.au

 

Bruce.

 

 

[maulonir]

Hello Howard,

 

HTL,CTL,LTL all relate to the where the thrust line is in relation to the COG. This is a huge subject and as been debated over and over in the gyro world as to which is safest/best design. HTL gyro's have been a major contributor to fatalities around the world, and the last 3 fatals in OZ all invloved HLT designs. Visit www.asra.org.au and join the forum, there is a wealth of information in there. There are also contacts listed that would be more than happy to explain the theory behind the differences in design. As for the tail contacting the ground on TO and landing thats quite normal. On TO the idea is to balance on the main wheels ocasionally or if performing a short field TO the tail wheel will contact the ground. There is not allot of force being applied to it under normal conditions I guess not much different from the tail wheel contacting first when landing a tail dragger FW.

 

Hope this helps

 

Rob

 

 

[Guest Howard Hughes]

Thanks Bruce and Rob, have joined the ASRA forum. Thanks for the explanation regarding thrust lines, how does a newbie know which category each gyro falls into?

 

 

[bones]

Also how do these terms relate to the following craft:

Xenon Gyros

 

Magni Gyros (in particular M-24)

 

MTO Sport

 

Sportcopter

 

Cheers, HH.:thumb_up:

 

PS: More questions to follow I'm sure!

Howard,

 

Been away working, back home for a week of R&R and unload :)

 

The makes of machnies you listed above i will try to cover as fairly as i can.

 

Xenon's are as close to clt as possible really, The cog does change in flight as fuel ect burns off, this is the same for all aircraft i guess.

 

M-24 now IMHO is htl, BUT it has a huge hs to counter this, and from reports flys stable.

 

mto sport, close to clt from reports, but they have started having frame cracking issues, and offer problems of late with the rotor intersecting the prop, so if you make a bo bo, you shorten the prop.

 

sportcopter, would be close to clt also, though i dont know if there is a dealer in OZ as they are Yanky made.

 

On take off the rear wheel doesnt/shouldnt touch the ground, but in landing the best and shortest way to land is to land tail wheel first, and really load the rotors to stop short, the machines are designed for this so no probs there,

 

Be gone again on the week end, but Rob can help you out with most questions i would think.

 

 

[winsor68]

So.... High Thrust Line is bad....

 

Is there disadvantages to having a Low Thrust Line?

 

 

[maulonir]

G'day Bones was just about to reply when you chimed in.

 

Howard,

 

Visually you can generally tell if a gyro is HTL CTL or LTL. HTL would usually have the prop up high and the pilot fuel etc and engine below the thrust line. LTL is generally the opposite to this and CLT is somewhere in between. The only accurate way of telling is by doing a double hang test or weight and balance calcs to find the COG and see where the prop thrust intersects it.

 

Also HTL machine should nose down on application of power and nose up when power is reduced. LTL machine would nose up when power is applied and nose down when power is reduced. CTL machine should not have any major pitch change when power settings are changed but should decend when power is cut and climb when power is applied. This will of coarse vary between machines as air speed and drag will affect the machines reactions aswell.

 

Rob

 

 

[bones]

So.... High Thrust Line is bad....Is there disadvantages to having a Low Thrust Line?

A LTL machine can throw issues at you also, the ideal machine should be within about 50mm + or - from clt.

 

It is not that hard to design and build a machine close to CLT, why some manufacturers dont is beyond me, apart from the fact that to get it CLT usually the seating needs to be high so this makes it harder to get into, so they stick with the low seat, for costumer appeal, but they forget to say ohhh its easy to get into but it will kill you in a heart beat with the right conditions, this is very aplicable to a make of machine you didnt mention.

 

The HTL becomes an issue when if you can visualise the following.

 

The only thing stoping the machnie from rolling forward in the sky, is the drag of the rotors, then all you need is a thermal/wind shear to take that drag away for a split second, and over it will go, and it will get to an unrecoverable situation in less than 1 second, especially at high speed with a high power setting on the motor.

 

A CLT should hold a similar path even with the rotor drag removed as above, and the rotors will grab again before things go pear shaped.

 

A very LTL machine can cause other issues.

 

This is dependant on a lot of variables of course, but it has happened alot to a particular type of machine, even killing instructors, mostly in the US, but they have burning holes in the ground all over the world, cant remember one in OZ.

 

Hope that helps :thumb_up:

 

 

[maulonir]

It would have to be an extremly LTL to flip a machine over backwards but I guess theoretically possible, I don't know of any though.

 

Bones you confused me for a minute there (not hard to do) I thought you were refering to a LTL machine in the bottom paragraph when I first read it as it follows on from the "A LTL in theory will/can flip it over backwards."

 

But i guess you were refering to the RAF which is a HTL machine for those unfamiliar with this particular Gyro.

 

Rob

 

Rob

 

 

[bones]

Rob,

 

Yep not one of my brighter moments, so i changed it abit, cause im too lazy to type another big one:)

 

 

[dazza 38]

Thanks Guys and Howard for starting this thread, i have found it very interesting and educational.Cheers

 

 

[Guest Howard Hughes]

Thanks Bones and Rob,

 

That was the sort of info I was after and has made it quite a bit clearer for me. I see gyros as the ultimate freedom machine, but was getting quite confused on the fling wing forums with all the talk of thrust lines.

 

Thanks again, HH.:thumb_up:

 

PS: Also thanks to those who sent PM's.

 

 

[lantianzhiyu]

Theoretically at all aircraft rotorcraft is safe. In mainland China, there are no open low. All aircraft flight DIY is illegal. If the low-level open, I believe that China's small plane has a huge development, and the huge market.

 

 

[lantianzhiyu]

Theoretically, all aircraft rotorcraft is safe. In China, there is no open low. All manned DIY machine fly is illegal. If the realization, I believe that China's low open the small aircraft have a vast development space and huge market.

 

理论上,在所有飞机中旋翼机是最安全的。　　在中国大陆,那里还没有开放低空。所有载人DIY机飞行是违法的。　　如果实现低空开放,我相信中国的小型飞机有一个巨大的发展空间和巨大的市场。

 

 

[dazza 38]

Theoretically at all aircraft rotorcraft is safe. In mainland China, there are no open low. All aircraft flight DIY is illegal. If the low-level open, I believe that China's small plane has a huge development, and the huge market.

I think your right mate.China is going to be a massive market for aviation.Thanks for posting.

 

 

[jeff b]

The MTO's now have 1000 machines out there with one aircraft recorded with a frame crack and history not reported. The frames have compulsory dye penetrant testing at 1500hrs to check. An AD resolved the prop rotor clearance pretty quickly. Lots of fun in this aircraft.

 

Jeff.

 

MTO Sport 914.

 

 

[bones]

You had better not write about that again then Bones, lest you get into trouble:cops:.I understand you like gyrocopters, gyroplanes and autogyros. I came across a very interesting website about Xenon gyrocopters/gyroplanes/autogyros (I am clearly not the first because it tells me that I am the 13,553,221st visitor!). There are some really lovely looking gyrocopters, gyroplanes and autogyros on that site. I did not come across a good explanation why the second N in Xenon is not pronounced and the first one is, especially when it IS pronounced in the periodic table of the elements but that is a minor side issue.

 

I really love the look of the Xenons but, I have to admit that about five years ago, I actually considered acquiring one* but there appeared to be some uncertainty about the business' ongoing existence; I believe they are still operational. But more recently, I have become a bit sceptical about the safety claims of gyrocopters, gyroplanes and autogyros , especially with the Pilot Induced Oscillation problems, etc.

 

In any case, I have bookmarked the http://www.zenogyro.com.au/ webpage so that I can have a better look at it when I have a bit more time.

 

Gyrocopters/gyroplanes/autogyros DO seem to have an identity crisis.

 

* The UFO Helithruster. http://www.ufo-helithruster.com/

Hope you dont mind Howard

 

Righto then as Eightyknots asked in the other thread, here is my attemp to answer them for everyones info(if they were interested).

 

Xenon is a french name, and as so you pronounce it as Zeno.

 

First of all yes the factory that makes the xenon did have a big blow up 2 years ago, the so called designer and the man with the money had a falling out.

 

The owner of the factory and and molds and basically the rights to make the machines as of now, but had to change the name to Zen1, but basically the same but better machine.

 

Most modern day factory built machines should be safe in the face of the PIO(pilot inducted oscillations), which if not stopped would lead to PPO(power push over), also yaw stability ect, how ever the UFO you mention, well lets just say not in the same town let alone ball park, they look like they would put a horn on a jelly fish, but there has been a couple of fatal crashes involving them that can not be explained without the "possiblity" of some reall funny stuff going on, ie. no one really knows what happened, and no noe is game to try it. the last i heard the UFO have gone under ground again, they are very heavy and dont perform anyway. So i wouldnt touch 1 with a 40ft pole.

 

Yes unfortunately the Gyros still suffer from an image from many years ago when there was no 2 seat machines to instruct in, and as such every one taught themself to fly, and as such the result was and sadly still happens today(trying to teach themself to fly), alot of people killing themself.

 

All i can say to people on the safety front of the gyro is i done just over 2500hrs in gyros, most of the mustering, about 450hrs instructing, and i am still here giving cheek, as long as someone chooses a safe design and gets prior and propper training, they can enjoy many hrs of ear to ear smile flying.

 

I think i just read your post propperly, and you were mainly asking about the UFO? hmm well you got some other reading anyway :)

 

 

[Gentreau]

Excellent thread, anyone got any input on the Magni gyros ?

 

.

 

 

[Guest Howard Hughes]

Hope you dont mind Howard

The more talk about gyro's (especially Xenons) the better!

 

 

[eightyknots]

Hope you dont mind HowardRighto then as Eightyknots asked in the other thread, here is my attemp to answer them for everyones info(if they were interested).

 

Xenon is a french name, and as so you pronounce it as Zeno.

 

First of all yes the factory that makes the xenon did have a big blow up 2 years ago, the so called designer and the man with the money had a falling out.

 

The owner of the factory and and molds and basically the rights to make the machines as of now, but had to change the name to Zen1, but basically the same but better machine.

 

Most modern day factory built machines should be safe in the face of the PIO(pilot inducted oscillations), which if not stopped would lead to PPO(power push over), also yaw stability ect, how ever the UFO you mention, well lets just say not in the same town let alone ball park, they look like they would put a horn on a jelly fish, but there has been a couple of fatal crashes involving them that can not be explained without the "possiblity" of some reall funny stuff going on, ie. no one really knows what happened, and no noe is game to try it. the last i heard the UFO have gone under ground again, they are very heavy and dont perform anyway. So i wouldnt touch 1 with a 40ft pole.

 

Yes unfortunately the Gyros still suffer from an image from many years ago when there was no 2 seat machines to instruct in, and as such every one taught themself to fly, and as such the result was and sadly still happens today(trying to teach themself to fly), alot of people killing themself.

 

All i can say to people on the safety front of the gyro is i done just over 2500hrs in gyros, most of the mustering, about 450hrs instructing, and i am still here giving cheek, as long as someone chooses a safe design and gets prior and propper training, they can enjoy many hrs of ear to ear smile flying.

 

I think i just read your post propperly, and you were mainly asking about the UFO? hmm well you got some other reading anyway :)

Thanks for all that info.

 

I have a question about the Rotax RST. Are you the importer for this? Is this available to buy engine only (e.g., if this was required for a fixed wing aircraft?)

 

 

[LimaMike08]

http://www.gtgyroplanes.com.au/

 

Have you checked out the GT gyros HH? They look like a great machine as well and I have seen a few YouTube videos of them as well.

 

Gets me excited.

 

 

[bones]

Thanks for all that info.I have a question about the Rotax RST. Are you the importer for this? Is this available to buy engine only (e.g., if this was required for a fixed wing aircraft?)

yep i can get just the engine along with the after cooler for about 21k Euro plus freight ect of course. Mount straight up with the standard rotax ring mount and your done, 135hp, the machine in Darwin would have close to 900hrs on it by now.

 

 

[bones]

http://www.gtgyroplanes.com.au/Have you checked out the GT gyros HH? They look like a great machine as well and I have seen a few YouTube videos of them as well.

Gets me excited.

Yep they look good, and from all reports handle great, i have never been in one personally, now because the gyro is such a very draggy machine, you really need to look at power to weight ratio, so if you do that you will find a fairly sad equation, dont get me wrong i offered to sell them if they put a rotax motor in them but they wouldnt, so i dont :) i not gonna get nito pricing but if you do your sums, you can get a machine with a propper engine(rotax) for the same or less.

They used to have a subaru engine then about 2 years ago they went to the suziki engine with the turbo, and i sat down and done the sums and according to their website, they are actually worse off now as far as power to weight. they kept telling me you need hp, yes you do if you got to lift a sh*t load of weight, if you lower the weight of the machine you dont need that much hp, i have got xenons flying on 100hp rotax, and even with 2 up they fly good not great but the motor does it quiet well.

 

Hope this helps some what.