I had this Idea the other day, which I havn’t yet tried, which is to make land yacht wheels that are sharp edged disks, instead of the conventional rubber wheels. The Landyachts I’ve seen have those ball-bearing rollerblade wheels which seemed to work quite well, but there was some tendancy to side slip, and what the heck, it never hurts to try something else. I was also thinking that larger diameter wheels with spokes, to cut wind drag, would have a larger area of contact with the ground, and also more leverage to overcome friction in the bearings. If they were sharp edged too maybe they’d work.
I had a land yacht that had old model airplane wheels that weren’t as good as the rollerblades
I’m thinking of ways to make my own good wheels cheaper. Not that the roller blade ones are all that expensive.If the wheel shaft is as thin as possible in a very small tube mounted in the wheel, maybe it would work well.
john
have you ever tried looking into wwI model airplane wheel. i dont know if they will work, but the will be light enough and should allow for you land yacht to roll.
cougar
long live the cup and cris dickson
Hi John,
I’ve read many of your posts & had no idea you were interested in land yachts. That’s great!
Your comment about the disc shaped wheels is interesting & I think it’s largely a matter of what sort of surface you’re running on. Full sized land yachts are mainly using dry lake beds or hard packed sand beaches (www.nalsa.org ). The Fed 5 class is a good example of what you are talking about: http://www.iceboat.org/RCBoats/ivanpah04/11s&r.jpg A sharp edged disc may tend to “dig in” to many surfaces. Many of the drylake sailors go for a more conventional wide based wheel http://www.iceboat.org/RCBoats/ivanpah04/3Dale.jpg My experience with models has been mainly on blacktop, ice & Dry Lake Ivanpah http://www.iceboat.org/RCBoats/ivanpah04/12k-1.jpg After playing around with inline skate wheels on blacktop (too much side slippage/crabbing), I’ve found that foam model airplane wheels are the best way to go (Dave Brown wheels at Tower Hobby). It’s best if these are retrofitted with bearings. Others have had good results from Dubro inflatable tires or some of the scooter wheels having a soft(low number) “Durometer” rating.
You offer two competing ideas in your post. One is greater contact area and the other is less contact area. I think the reason that Rollerblade wheels do not work so well is that they are designed to have a large fraction of a 120 - 200 lb person pressing down on them to give them grip. Their durometer is just too hard to be used with only a few pounds of down force going through the wheels.
Bill suggests that softer wheels work best. I have these on my model Nite iceboat/land yacht and they work really well (not much sideslip). I have not tried any other wheels as this is what Tony supplied with the boat and he indicated that they work the best of all the wheels he has tried.
So I am with Bill. The softer wheels will work best.
I would stay away from the larger diameter wheels because I think you will just have too much windage. Keep in mind that the full size land yachters are putting wheel fairings over their wheels to cut down on the windage of the wheels. This is probably a better idea than larger diameters. Other than that, make sure you have a good set of bearings.
I think there is more speed gains to be made with rig design, rig cant, plank flexure and hull fairing.
I think you are missing an huge advantage to a non rollerblade wheel…weight. Rollerblade wheels weight allot and rolling weight in much greater than static weight.
I made my own wheels for my land Yacht, they were plumbing pipe plugs. I used 2" plugs (hard white plastic) with 2" rubber O rings glued on the plug, I used brass tubing for bearings and some teflon grease to lube it up. They weigh almost nothing and work great!!
Only speaking humbly and theoretically, maybe something as light as a land yacht doesn’t need wheels with large ground contact but wheels that only need to catch to prevent side slip, if you know what I mean, on small cracks, bumps, defects etc, on the pavement. If you then lengthen this razor contact with the ground with a larger diameter wheel, you can catch more bumps. You then have to have spokes, which don’t need to be very supstantial because the thing is so light, to reduce windage. Guess you can’t make them too fragile though. Has anybody ever compared wheel pants to spoked wheels in terms of wind drag? Hmmmmm
John - to a point, larger diameter wheels make sense, especially if they aren’t solid. Rolling over hollows instead of dropping into them! That is why we use 21 inch front wheels and 18 inch rear wheels on our motocross bikes… easier to steer and less effected by holes, bumps, etc.
The are just starting to come out with r/c motorcycles, and if they have spoked wheels, it might be worth a try. I am also leaning toward Will’s/Bill’s ideas about a softer tread compound. And if the wheel is angled in at the top I would feel/guess it would help to resist sideslip. In the meantime, I have a set of old rollerblades from son that are about to be considered for disposal (ie - wheel removal) and those may find a new life as a landyacht.
Anybody for a regional/national event in Mall of America parking lot - top floor of the west ramp? Bring the wives and let them go shopping. Maybe we could get MOA to sponsor the whole thing.
the "aero “discs” are more for reducing drag than cross wind effect worries. Those using the carbon fiber disks generally are on a closed, circular track with little if any cross winds to worry about, while road racing tends to stay with spokes. In fact, a lot of the Tour bikes still use metal spokes, or - large (usually three spoked) carbon fiber wheels. The 3 spoke wheels provide light weight, yet still allow cross winds to go through without upsetting the bikes balance in out-door, cross country racing. Indoors with virtually no wind, riders are much more concerned with drag and probably streamline as much as possible to cut down on any wind resistance. And - yes, there are tour bikes using the fiber discs too - but usually they are a minority in road race competition at the pro level.
Interesting point though, as I went back and looked at my saved video tapes of the 2004 event, I saw Lance Armstrong used spoked and “disked” almost equally - but the disk-wheels were often used in time trials, and the spoked wheels in his mountain leg races. Now you’ve got me wondering.
As far as aerodynamic drag from wheels is concerned, my vote would go for a smooth solid wheel. I have trouble imagining why a spoked wheel would have less drag. Tom Speer notes that parasitic drag from wheels can be a significant factor on full sized land yachts
( http://groups.msn.com/LandsailerandIceboatdesignandconstruction/general.msnw?action=get_message&mview=0&ID_Message=9&LastModified=4675491721474606092 ) and advocates wheel fairings that take into account direction of the apparant wind. However, at the speeds these models will experience (15-30 mph), I’m not sure that it’s really as big of a factor as something going 70 mph. As Will has noted, rig design, wheel lateral traction, etc, will likely be a much larger factor in ultimate speed potential.
