Wheel Spacings

[asra]

Can anyone tell me if there's a formula which indicates the correct wheel spacings, not just between the mains but the overall distance between all three for good ground handling?Obviously too short a distance forward of the mains creates a machine capable of wobbling in ground handling and too long means super human efforts required to turn to a new direction.So what's a good distance?TedHey Barry, if this is in the wrong area, feel free to shift, but don't whinge to me about it otherwise I'll sic Mad Dog Russell on to you. Just joking Barry[][][]

[asra]

A good distance is the one between you and Darwin, guaranteed to work[]Russ....A1014 NT....gods country

[asra]

Another good distance is you underneath the duals of a Mack truck, but thankfully I'm more tolerant of your missus's needs for a partner. []Ted

[asra]

The "Ground Handling" thread has got a bit away from the question Ted asked, and my comments probably apply to it as well as this one, in that it's being regarded as a piloting problem rather than a design problem. Don't forget that with this current obsession with CLT and a higher C of G we are tending to build this problem in. Pazmany, the landing gear guru has information on calculating the "Roll over angle", which I can't recall at the moment. Obviously it relates wheel base, track and Cof G position to give a configuration regarded as acceptable for most aircraft.Of course we have to recognise the stabilising effect of our energised rotor.Geg Gremminger's views on this subject may require some concentration, but I believe make the most sense.Another thing we must recognise is that a learner needs more ground stability than an experienced Gyronaut, and we are perhaps doing him a great disservice by steering him toward CLT too early in his career.Who's going to be first to bite my head off! John EvansThink logically and do things well, think laterally and do things better.

[Tim]

My turn. Ted's question is a good one and to answer it bluntly - no, as far as I am aware there is no formula indicating wheel spacings. As John said though, there are things to consider. The roll over angle refers to the angle that the gyro will roll over either sideways or "front corner". The only design considerations in a sideways roll over are wheel track and height of the C of G. The wider the track, the better, and the lower the C of G the more ground stable.In a "front corner" roll over, the design considerations are the C of G (the lower the better) and the wheelbase (the longer the better) To a lesser extent the steering lock and the front brake efficiency also can contribute to front corner roll over. (the less the steerng lock and the less sensitive the steering the better.This is all well and good for ground stability but the low C of G is not good for flight stability. It all becomes a balancing act between handling, stability, design and pilot proficiency.Tim McClure

[asra]

Image Insert: 30.81

[asra]

You don't tip chute frames over, they are hanging under the chute and can be treated very ordinary without problems.Image Insert: 11.7

[asra]

So, in thinking about Dominator gyros, would they need a wider main wheel track because of their height as compared to say a RAF?The other question that comes to mind is does a tandem type gyro turn or track better or worse than a single seater or side x side?Ted

[asra]

Phil raises the concept of trainer wheels for beginners.... I think it seriously deserves some more thought. Obviously newbies are not all that concerned with maximising the take off or cruise performances but rather the "well I'm off the ground... now can I make it back down without a red face"???I'm all for doing it the easy way until I become confident.Ted

[asra]

thanks Ted, I was just using the pic to show 2 wheels under a wide frame. I've talk to pilots that have given themselves a real scare doin strip runs , bunny hops, crow hops , watever you wan't call it. I remember when I bought my K100RS in 1984, BMW were trialin ABS brakes and they had an outrigger, castor setup on the bikes whick kept them upright will testing.

[asra]

One thing to remember is that a lot of gyro 'tip overs' are actually 'fly overs'. They happen right after touch down when the disc is still very active and the gyro is actually pulled over. I'm not sure than any kind of landing gear could help that much.

[asra]

G,day.Do Gyro's have to be of a tricycle under carrage type ?Could they not be more of a taildragger configeration with a steerable tailwheel ? The mains could be placed far enough backto enable it to raise the tail on the takeoff run.Maybe less likely to have a fly over, perhaps. A ground loop might be preferable if you have got it all stuffed up !Has it been tried ?Robert DunnMackay. Qld.Growing old is good while it lasts.

[Tim]

It has been tried many times. Generally speaking, tricycle is more ground stable than tail dragger, simply because the main wheels are behind the C of G instead of in front of it. A tail dragger is always trying to swap ends and it is only deft control by the pilot that keeps it straight.I think that in most cases of beginner roll over, it is not a case of only just rolling over, but doing so rather convincingly. I do not feel that most of the ground stability enhancements would help in 90% of the cases. Far better would be more training or experience.Tim McClure

[asra]

I know Jim Mayfield was working on a taildragger version of the Sparrowhawk and a tandem, 2-seat taildragger before he left AAI. I don't know whether or not they have continued development in his absence. The main reasons were for weight reduction and rough fields.

[asra]

Hmmm... needs more thinking here I believe.Ted