Monday, December 8, 2014

A Good Run (on the Ice)


Ive been "skeletoning" several times since I got back from my travels... The winter is here and as of November 10th the Skeleton/Bobsled/Luge track at Whistler has been open. Im taking it more seriously this season and am intending to slide at least twice a week throughout the season. Its a lot of driving to and from Whistler but there are a couple of others who I ride share with and Im definitely enjoying it.
Me coming up the finishing ramp

Me in the bottom corner  (#16) at about 125Kmh
 
We have a new coach this year and one of the "tasks" he gave us was to write a detailed account of what a run feels like to us so that he can assess what our current skills are and where we have difficulty/what we are working on... Its really hard for coaches since they can only ever see one corner of the track at a time and we blast through in a second or two (at 120Kmh or so)... Not a lot of time to see whats happening!
Anyway, I thought Id share with you my description of "a Good run"
...
Im in the athlete’s waiting room at the mens luge start. Its between turns 2 and 3 of the 16 turn track…not quite the top of the track but Im sure Ill get there soon enough. Im fully dressed in my sliding gear with my track spikes on, a lycra speed suit, gloves, and my streamlined helmet hanging on the wall… waiting… It’s a few minutes before its my turn on the ice. There are a couple of other athletes in the room but I don’t really have anything to say to them and for the most part I just want to be in my own space… Lots of athletes use this time to “visualize” their coming run, but I don’t really go in for that much and I prefer to just walk quietly around the room. I do try to think through what Im going to do on this run with specifically what Im going to do that I try to always do and also what Im going to do that’s different this time to try to get a better run. I go over my intentions a few times but I don’t really visualize it per se.

Anyway, the tower calls the slider who is up before me to the ice and about a minute after that I collect my helmet and head outside to the track as well… There are less people there and I like the feel of the cold air for a couple of minutes before my run. The other slider is just starting down the track now so I go get my sled and walk it to the edge of the track. We (me and the track crew guy who will “release” me to slide) wait the minute or so till the previous slider has finished their run and the tower calls my name to come to the track. I walk out onto the track and lay the sled down. The track guy sticks his boot in front of one of the sled runners and I stand behind the sled and wait a few seconds more with one more mental run through of the main personal intention for this run… like maybe “hold up for a moment at the end of 6 so I can drive hard across into 7” or some such). The tower announces “one minute to start” and I pull my helmet down on my head, sinch up the strap, check the alignment of the sled and then lower myself down onto the sled in a face forward prone position… I feel the cold of the ice on my face through the visor just a couple of cm away. I feel for my correct position on the sled and inch forward or back just a bit to get it just right. Then I set my heels together and point my toes while tucking my shoulders slightly together and pull my elbows into my sides and firmly grip the hand holds… I stay looking down at the ice rather than forward down the track for the moment. I wait till the track guy asks if Im ready and I nod and start craning my neck so I can see along the track ahead… The track guy pulls his boot away and tells the tower over his radio that the “skeleton is in track”…

And we’re off… very slowly the sled starts to move forward toward the first turn… It’s a very gentle turn and with such low speed I can do little to steer other than drag one or other toe to try to direct my sled to one or other side a bit… I want a good line here because if it’s a bad line the sled will skid and skitter for a while till gravity gets it in the right line and that slows the run time down a lot. I drag my left toe just enough and the sled takes a good line into three and the white track walls slide past smoothly as I gain a little speed through three and then out into a short straight section before a sharper right into four and Im starting to move along now, into four there is still not much I can do to control things but there is little need to anyway… My only concern is to be not skidding. Im running good so I simply self check and make sure my heels are together and my arms are in and Im hanging on… firmly but not too tight… I want to stay flexible rather than rigid. Coming out of four Im now at a speed that I can start to do a little and I give my neck a twist to the left to get ready for the coming twists… The line is now starting to matter and I want to be on the right side (early) but my line is good and I wait till the sled starts climbing the ice at the start of five and then I sort of mentally pull myself through the corner, driving gently down with my right shoulder while I crane my neck a little to the left to try to see around the corner.

Five is short and gentle and as I come out of five I let off the shoulder pressure and Im moving pretty quick and the tendency is for me to want to raise my chest of the sled as I approach six. I mentally resist the urge and push my shoulders back down and again start mentally pulling myself through the corner and twisting my head to the left and craning to look up in the direction of the track as hard as I can. There is the rush of air and the sound of the runners is now significant as I feel the G forces push firmly on me for the first time… Six is longer and stronger than five and the exit is important to get over into seven. For the couple of seconds that Im in six Im again driving the sled with my right shoulder pushing more firmly on the sled than my left… Im feeling the gravity and seeing the white walls scudding buy and Im watching hard to see when Im getting toward the end of the corner and a bit before I see the exit I reverse my shoulder pressure to try to hold the sled up on the side wall just a bit longer than it wants to be there, and then as soon as I see the exit I swap the pressure again and drive my right shoulder down hard… Im out of position here with my left shoulder up off the sled by a couple of cm cos I really want to get as far to the left as I can going into 7. The short straight between six and seven flashes past and I see someone standing there on the right at the corner seven start ramp but I have no idea who it is and I don’t care because Im totally focused on seeing my line and how early I am going to get into 7… This run is good and Im over early and as soon as I start into seven and before I feel the Gs, Ive swapped shoulder pressure again as hard as I can to steer back  right into seven. Seven is long and firm and for me has two or even three “swoops”… I feel the Gs build somewhat and as they peak I ease up on the left shoulder and go neautral as the sled is up on the wall and I just want it to stay more or less there.. But the sled fades down a bit before climbing again and the Gs come on a bit more again and I drive with the left shoulder again... and I hold it all the way through now till Im out into the long and not quite straight eight. Ideally I would not touch the walls here but the risk is that I will come into nine late and that’s hard to fix so my intent is to have a gentle hit on the left wall to reflect me into a good line for an early entry to nine… I hit the wall and hear the grind of the ice and know that cost me speed and also upset the sled… Im instinctively tempted to drag a toe to straighten out the sled after the hit but this time the reflection is pretty smooth and the sled line is on target for an early nine so I just focus for the moment on getting my limbs all back into form with shoulders down and heels together.

Speed is good now and nine is a solid left that gives me a good push down into the track. I resist the push but try not to let my shoulders come up. Im not really driving in this one but as I come out of the turn Im craning to look ahead into ten which is another left that’s stronger because of my extra speed. The short straight flashes past and Im into ten and Im concentrating again just like in six … Im driving around ten with some right shoulder pressure and my mental “pull” but toward the end of the turn I ease up to try to let the sled hang on the wall a little and as soon as I see the exit Im driving as hard as I can with the opposite shoulder to again try to get over to the other side of the track to get into eleven early… I vaguely note the closed barriers of the corner eleven entry point as it flashes past but there is no one there watching this time. Again I seem to have a good line on this one and as soon as I start into eleven I start driving to the right with my left shoulder. The Gs are pretty strong now and I try to ease off on the drive as the Gs peak and I wait through the long dip in the middle before the Gs build up more again toward the end… I drive with the left shoulder again and I also drop my right toe and let it drag for the last pressure hump of eleven. Then its out of eleven and as the Gs abate I lift the toe and get back in form. I see twelve racing toward me at the end of the short straight and there is no time to do much of anything other than to remember that I want an early entry … if not then Ill get a strong hit on the left wall on the other side but again it’s a pretty good line and the short straight flashes past and Im into the sharp left of twelve. Again the Gs push me down and Im struggling to see ahead but I need to so I can time my left foot dab… I only manage to remember to do this about 50% of the time coss things are happening so quickly, but this time I get it right and I hold the left foot down for a few tenths of a second as I exit twelve and I enjoy a good clean exit with no wall hit to unsettle my position or the sled line and Im heading smoothly into the gentle right of thirteen on a great line… With a good line through seven, and eleven and no hit out of twelve Im really moving fast now and things now just come at me and Im largely along for the ride!... I see the entry of fourteen (strong left) rushing up and Im hoping for an early entry… It looks OK and I brace myself firmly, holding on with my arms and resist the surge of Gs in the corner.. I am no longer pulling myself through the corners and Im “driving” by instinct, letting the turn hold down the right shoulder while I resist with the left and Im looking straight down at the ice rather than ahead as the forces try to squish me into the wall… This is a fast run and I literally let out a short loud groan/grunt as I flash through the pressure point and out into the short straight. Im having to hang on quite firmly here as the sled rolls suddenly back to horizontal and then Ive got just a moment to look forward again and brace myself for fifteen which is a mirror image of fourteen… Again I am wrenched around as the sled rolls onto the wall and again Im crushed into the sled… another grunt and Im through the pressure and the sled wrenches my body around to flat again while gravity seems to disappear for a moment and I try to get my bearings… It’s the final corner now and moments later I feel the crushing Gs of the first swoop of sixteen. I know I need to drive here so while Im desperately trying not to get my face forced into the ice, Im pushing down hard with my left shoulder and trying not to let the Gs push in on my right while I am again shouting a long arrrrrgh through clenched teeth.. then the Gs reduce as the sled comes down off the wall a bit as the colours of the painted “Whistler” in the track ice flash past and I try to stop driving right but in truth Im always late letting the steering pressure off… But no time to worry about that now as I feel the second pressure build . I can barely see anything and the world is flashing past at ludicrous speed. Im shouting again and resisting the Gs with all my strength but I know I have to steer here so I drag the right foot till I feel the pressure reducing again and I struggle to get my head into a position where I can see the exit… I lift my foot again before the turn ends and Im flashing out of the corner and into the straight and up the exit ramp. I dabbed that foot just enough and my line is pretty central in the exit run. Im over the red finish line now with speed reducing fast and then out from under the roof and into the open. I can see the track crew and first aid people beside the track as I slide up the finish ramp toward the dock. I know I did a fast run because my speed is holding and Im going to go high …I let go of the sled and raise my shoulders and get ready to get off. As the sled comes to a stop a couple meters below the crest, I get up and push it over the crest and onto the flat. Then I stand it up and undo my chin strap and push my helmet up off my face, wearing it as a hat and I man-handle my 25Kg sled out of the track and rest it on a rack to wait for my next ride to the top.  I head into the warmth of the waiting room with a smile on my face… A good run.
 
... and all that took about 1 minute!, and I get to do that a maximum of three times in an evening for which I have driven about two hours up from Vancouver and will have to drive two more hours back down after the session!...
 
Yeah, I know, Im crazy :)

Gravity Bike

Ive started a winter project...

Im gonna build a "gravity bike" and see how fast I can roll down a hill.
Ive thought about all sorts of possible configurations for things with the ultimate aim of going as fast as possible on a road while being propelled by nothing but gravity.
Essentially that brings two different forces into play with gravity pulling you down hill, and friction resisting your motion... The two forces will balance out at some point and that's your maximum speed... Im aiming for something above 100Kmh.

In order to minimize friction I want to be as stream-lined as possible and with the smallest possible frontal area. To maximize the forces from gravity I want to be as heavy as possible.
... and (letting survivability have its say) I also want sufficient control to be able to avoid obstacles, stay on the road, and stop in a hurry if I have to.

And Ive decided that Ill take the project in steps too so that I can prove out different aspects of my design as I proceed and don't go spending large amounts of money on things that wont work.

Initially I was very attracted to the idea of starting with a recumbent trike that I could modify a bit and build a stream-lined fairing for... But a decent trike is a very expensive piece of hardware (minimum $2000) which was a bit much... So, then I considered building something from scratch but that would cost me a lot too and Ide end up with less functionality than the commercial trike route.
So then I decided Id consider two wheels rather than three, though the idea of getting a flat tire while traveling at these speeds on a bicycle does scare me quite a bit more on a bike than on a trike!

So I looked into recumbent bicycles but they still cost about $1000 minimum.
And so I finally settled on something much simpler as a start point... A BMX bike.

Im going to modify a kids BMX bike as a base platform.
It may sound a bit strange but it has a bunch of the features that I want: Its got a very low centre of gravity with the small 20" wheels. A kids bike is usually well made but uses thick walled heavy gauge steel tubes... which is fine for my application as it adds weight and strength. I can get one with disc brakes too and that makes it way cheaper than having my own set of custom 20" wheels built. And finally of course its much cheaper than the fancier options.

So, I looked at quite a few second-hand bikes on Craigslist and they are often very cheap or free but I couldn't find any disc-brake bikes around (new teck for BMXs). But I did find a relatively cheap new one and I went and bought that for a couple of hundred dollars.
 
The BMX bike in original configuration.
 
And now Im going to modify it significantly for my purposes. But for the moment Im going to try not do make any mods that are permanent so that if things don't work out as Im hoping then I can just put the bike back together and sell it for close to what I bought it for.

So, the mods so far include:
Remove seat, peddles crank-set and chain... I will not be peddling this anywhere :)
Invert the bike frame... It gives the head-set a steeper rake that makes the bike more stable at speed.
Invert the handle-bars... Lets my hands be much lower and further forward.
Add foot rests to the rear axle stubs and put spoke covers on the rear wheel.

And the bike currently looks like this:
 

And while that looks really odd for a bike, its not really a regular bike any more. All I have to add now is some foam padding to the top tube for my body to lay on, a strong rear wheel fender so my back-side does not rub on the rear wheel, and a couple of knee/shin rests that will attach to the seat-post. Then it will be ready for some test runs.

It is ridden something like this (and yes, absolutely, I will be wearing full motorbike riding protective equipment!:

Photo copyright J. Maus

If my road tests are successful then I expect Ill be building a full body streamlined fairing for the bike... I may continue to use the bike frame as is or I may decide to do some cutting and welding to lengthen out the wheel-base (more stable ) and maybe also try a fully prone riding position (probably good for straight runs but not so good for twisty roads).

Oh and just in casy you were wondering, a bike like this is in fact completely legal on the public roads (assuming it does not exceed the speed limits) because it has standard bicycle brakes and can stop and turn the same as a regular bike (unlike street luge or skate-boards etc).

Anyway, that's my gravity bike project that is "underway"... Ill post again when there is something to say, though that may not be till next spring!