Danger - bicycle or scooter tyres as nose wheels

[NiqueNaque]

I'll use this forum as a form of incident report and a warning notice to those considering using a SPOKED bicycle or scooter wheel as a nose wheel or mains.Don't do it, point blankO NOT USE A BICYCLE OR SCOOTER WHEEL ON YOUR GYRO, THEY ARE NOT LOAD RATED FOR THIS APPLICATION.One of our members had one on his machine on an experimental basis, on pure coincidence and due to my only sometimes eagle eyes the member happened to turn his gyro into the apron from the strip from a final onto the runway, I was in the right spot at the right time [for once] and observed that his nose wheel twisted sideways when his machine bounced the nose while turning. We investigated when he came to a stop and had tied down, we found the spokes had all become significantly loose and that rim could move up to half an inch either side of centre. The brake pads [bicycle type] were buggered after about 3 hours of use and very limited use at that.Push bike and scooter wheels / hubs / spokes / rims are not load rated for what our gyros can dish out while under full power before they lift the nose wheel off the ground. Please do not use then for your gyro as you may suffer injury or death from so doing.The member concerned may file a report formally in writing at his earliest convenience and this notice will stand in its lieu. He has already sourced and procured a more solid arrangement to replace the scooter wheel and will fit it before any further flights are made.Regards,Nick.

[asra]

It would be nice to have seen a picture Nick.I don't think these wheels should be dismissed like that, obviously I am not challenging the facts as you present them as they are obviously correct for that particular wheel.When working on the replacement gyroglider [ now on ice ] I was planning to use such a wheel. However we did the appropriate load tests to demonstrate that it was up to the job.The requirements are spelled out in the Standards elsewhere on this site.I think the thing that disappoints me most about some of our Members is their unwillingnes to consult our documentation and do appropriate tests to determine the suitability of materials.Believe it or not we have the freedom to build the "custard and jelly aircraft" if it is appropriately engineered![:0]John EvansThink logically and do things well, think laterally and do things better.

[NiqueNaque]

Rob,Are you just stirring the jelly, or the custard?John,Sorry, I didn't have my camera at the time, I have to find it for repairs, it doesn't seem to be working so well these days so I've neglected to carry it with me lately.As to dismissal of these wheels generally, I suspect we would find that they are unsuitable, because if you think about it, a gyro in turning a corner can apply a good deal of sideways force on the wheel. If you were to have a look at how a bicycle wheel is designed to operate they typically have all their loads in the plane of rotation, even the front wheel, by virtue of the fact that you are leaning into a corner when turning, not so with a gyro because of the mains. I'd hazard that a wheelbarrowing incident could be completely unrecoverable with such a wheel due to the potential collapse of same. It may be a good idea to make a torture test rig with the wheel at 10 degrees off the vertical and a load of 100 kg imposed on it - drag it up the road and see how long it lasts.For my two cents worth I would not use one after seeing this, period.Regards,Nick.

[Ken Watson]

Spoked wheels are as strong as any other wheel laterally as long as it is the right one for the job.M.G used spoke wheels. Ken

[asra]

Yes Ken, I think Nick has missed the point, provided ther wheel is tested to the appropriate specs, and of course subjected to regular inspection for the problems Nick encountered it should be OK.If you consult the specs you will find that there is a figure given for the axial load it must bear.Bikes, particularly BMX and Mountain bikes are designed to tolerate the significant axial loads normal to their use. The wheel I was using stood up to a 100 kg axial load quite well.John EvansThink logically and do things well, think laterally and do things better.

[NiqueNaque]

Ken,I will observe that you are correct, if it is engineered for the job, as an M G wheel would be, I've worked on these wheels myself and am aware of their extremely solid construction, eg, spokes 1/4" diameter and better, with a substantial hub, etc.My point was in relation to "Scooter" and "Bicycle" wheels, not MG wheels.John,For how long did you test this wheel?I will note that the gyro that I have has racked up near 300 hours and has suffered a few nose wheel issues from what I am told of its history, including a caster bolt failure not long after I acquired same.As with prior postings we are now getting to the stage of over 1000's of hours being racked up on other machines.I will also note that a gyro weighs about 200 ~ 250 kg with pilot for a single seater, this is a stark contrast to about 100 kg for a bike and rider.The energy that can be rendered into the wheel by a gyro is phenominally greater, ie, for K.E = 0.5 x Mass x Velocity ^ 2, since it is unlikely a bike rider will usually achieve speeds of 40 kts on a regular basis, let alone 40 km/h, and I will observe across some rough ground - eg, grass strips. So, the mass is at least double, the speed is at least double, the shock factors are at least doubled and the end result is a 16 x greater risk of failure.Can I make the point any more bluntly?If you want a spoked wheel, put an M G wheel on it.Regards,Nick.

[birdy]

Ever seen them [very clever]clowns on the BMX thingys nik, the loads they put on them is more than you SHOULD be putn on your gyro wheel, and its not always streight down the spokes either.I'd suspect the spokes where loose to start with. I know you only need a few loose spokes on a scooter at 100mph to make you hang on with a death grip.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[NiqueNaque]

My apologies Birdy, I was editing my post while you did yours.I'll refer you to my prior post for your answer.Yes, I have seen BMX trick riders, but they don't weigh as much as a gyro, nor do they go as fast for as long. Consider a student pilot practicing balancing on the mains, especially a very green student, 10 hours of that would approximate a lifetime for a bicycle in terms of equivalent stresses, it might also approximate an injured student pilot in due course.Regards,Nick.

[asra]

Come off it Nick, what on earth are you doing with the nosewheel on the ground at 40 kts? If you keep this line of thinking up we'll all be wearing cast malleable iron nosewheels.John EvansThink logically and do things well, think laterally and do things better.

[Tim]

Nick your point is valid about the strength of the nose wheel, and we do have a standard that can be used for compliance testing if required. However your post does bring up another problem that you see at most flyinns - the practise of many gyronauts of hitting full power as soon as the rotors are "over the hump", in the mistaken belief that it will shorten the take off distance. Not only does it lengthen the take off distance but it also puts extreme stresses on critical components, including the nose wheel. Such "self learned" practices has been one reason for the introduction of bi-ennial flight reviews.The most weight put on the nose wheel should be while taxiing.Tim McClure

[asra]

We must aim for the lowest common denominator as they say!! The inexperienced pilot will on occaissions touch the nosewheel on the ground when they shouldn't. I have done it myself!!!and have seen some of the posters here do it when they were more inexperienced than they are now. Aussie Paul.[]www.firebirdgyros.com

[NiqueNaque]

John,If you care to ask Phil he might confirm that with a couple of hours of flight time in the two seater while training I had it on the ground doing 50 kts before lifting the nose wheel during a touch and go... it is possible. You may also remember a fellow named Jeff [M] and another named John [M] who wheel barrowed their machines into the dirt at Whittingham and ended their flying days on that note. 40 kts is more than possible, and hard contact under the wrong circumstance brings undone even the most sturdy of wheels and gyros, so I believe that engineering in a failure point is not an option.Regards,Nick.

[Brian]

Get a Rosco nosewheel and save yourself the worry and trouble of trying anything else !!! I have tried all possible ways to make it fail and it now has done 3800 hours and its still working just fine !!!!Brian

[asra]

Yeah Brian, a Rosco nosewheel in great. Got another one today in a box of goodies from Rosco. My Christmas day came early!!!!!Aussie Paul. []www.firebirdgyros.com

[Brian]

Yeh, I'm a bit conservative these days and I love stuff that has a lot of component testing built into it. I see particularly the USA guys sticking all sorts of untried and unproven stuff on a perfectly good gyro then post that the wizz bang part has failed in the first flight. I realize that advances have to be made and things have to be tried but not bits that are as vital as a nosewheel !!!Brian