Sunday, May 21, 2017

2WS With Split Hub Center Steering

"Split Hub Center Steering" is what I call the system used in the racer's steered rear suspension. A wing bearing universal joint connects the left side drive hub to the right side steering hub. Rear steering is 34% of the front, and in the same direction. 


Yes, steering geometry matters at the rear wheel as much as the front. A LOT of work was done to determine which geometry works and which doesn't. Instability from weaves, and speed wobbles with just the rear wheel, is no fun. That hasn't happened to this bike, but has happened with the electric one.

The drum brake rear wheel from the EX500 worked very well for this experiment. It is red because the donor bike came with a parts bike that had red wheels - no clever or creative aesthetics involved. The wheel was sent to Kosman Specialties to have the hub bored out back in 2009. That was the only machine work for this project that I didn't perform, since the wheel didn't fit in my lathe/mill.

The rest of the machined parts came out of my Grizzly G0516 lathe/mill. I got a lot of good parts out of that machine, but it has since been sold. The next racer will need more serious machinery located in a serious shop, rather than my kitchen (Seriously!).











Sunday, September 25, 2016

Race #7, 5, 1, and *

Ran the warm-up lap and gridded for the Formula Colorado class in MRA's Round 7, which was my 5th race ever, 1st race in 2 years, and pulled out at the end of lap 1: DNF. I thought I could quickly work my way back to previous lap times chasing the back of the grid, but it didn't work out that way. The hardware works great; the liveware, not so great. It is one thing to battle with someone else at the back of the grid (That is still racing), but when the entire field disappears in the first half lap and getting lapped within 3 laps is inevitable, then I don't feel like I belong out there. That said, I did get a lot more comfortable on it. Chicken strip reduction rate was ahead of expectation. Riding mistakes were getting easier to identify. Lines around the track were getting more obvious. The 2WS system was never a distraction: It steers far better, making it a lot less work to go faster. Trail braking is far more effective. We're going to have a lot more fun generating better results.


Yes, it is a lot of fun to show up at a racetrack with an exotic motorcycle, but motorcycle racing is ultimately about about the racing rather than the motorcycle. Other than some minor bodywork restoration and steering column modification, there's nothing left to do except race it. And work on a completely new design based on the same configuration and very little else.


Top photo: Tracy Helmhold

Monday, August 29, 2016

Track Time! Again!

This morning's track time at High Plains Raceway went very well. The track was initially opened to first time track riders to familiarize themselves with the track layout. That was a great opportunity to go out slowly and not worry about interfering with other people's idea of fun. And there were other things to worry about. Those first two laps were probably the most terrifying thing I've ever done, not that the racer did anything wrong, but rather, I didn't know what it might do wrong and without warning. There is no prior art available for the category of two wheel steering road racers or any experience to lean on. What I was riding was the culmination of earlier experiments based on a magazine article I read almost 30 years ago that stuck in my head. Will the front/rear coupled steering result in some sort of instability over bumps, or while cornering? Will the rear end wobble and structurally fail? Will the rear steering geometry that behaves while coasting misbehave while under power, braking, and/or hard up/down shifts? What about trail braking with linked brakes and linked steering? Will steering that works well at modest lean angles work under more severe cornering attitudes? Or worst worry of all: Is it merely another way to generate bad lap times with curious hardware, only to be pushed back into the shed and languish as a habitat for spiders?


After those first 2 laps and an hour or so of inspection (No loose or missing hardware! No adjustments needed at all!) and introspection (Do I really want to do this anymore? The turns are where I remember them 2 years ago, but where did my sense of timing go?), the doubt, confusion, and overwhelming sensory input that race tracks can provide somehow evolved into that powerful feeling that gets leathers, boots, helmet, and gloves back on with enthusiasm: Must! Go! Back! Out! That is a really good feeling!


The next 2 laps went a lot better. Even though I haven't ridden it (Or anything else) in 2 years, I still instinctively slid over on the seat to hang off into the corners. That isn't necessary anymore, since the 2WS system reduces lean angle a lot more than hanging off. The linked braking system is a huge improvement over the old system. Hard braking is drama free, as is trail braking into corners. Great brakes and steering systems might not sound too useful when they aren't being used properly, but they do wonders for improving confidence in the bike.


The last 3 laps were just a lot of fun trying to use what I learned earlier in the day. No lap times were recorded, but I'm looking forward to learning a lot more. The last MRA race of the season is at High Plains Raceway, 17-18 September, Formula Colorado class, car port #7.


Sunday, July 31, 2016

Done and Running. Again.

The racer was finally assembled enough to fire it up and ride it this afternoon. The test ride was only a 1st gear lap around a nearby parking lot, but it went very well - well enough to look forward to a test & tune day at the track. And if that goes well, we go racing. 


This has taken a lot longer than expected, but it has been worth the time and trouble.

11 August: Just signed up for the 29 August lapping day (Morning session) at High Plains Raceway. 

Wednesday, March 30, 2016

Plans, fun, and loose screws...

Most of the repair and modification work is done on the racer. All of the machine work is done. The new rear suspension is structurally finished. The current pile of parts, mostly unpainted, isn't photogenic, yet. The Dunlop GT501 tires I used to run were discontinued, so Pirellis have taken their place. If all goes well, the racer will get some track time for testing and raced this year! While better lap times are expected, it won't come close to breaking any lap records or getting on the podium.


I'm still confident that the next and better racer will get a lot closer to breaking lap records and getting on the podium. The next and better racer will share the same configuration and fundamental dimensions, but little else. A much lighter steel or aluminum ladder frame would be easy to make, but it still wouldn't be light enough. Exotic motorcycle frame design and construction methods really don't transfer to this configuration, but there sure seems to be a lot of potential with advanced aerospace methods. Exotic fabrications using aluminum honeycomb sound amazing, even if those are somewhat obsolete. What could be more intriguing than a motorcycle constructed with early supersonic jet era methods instead of barnstormer era biplane methods? 


Well, frame design can be described as a structural connect the dots puzzle. It is fun to imagine really exotic solutions, and even more fun to talk about. Concerns about material expense, tooling feasibility, repairability, maintenance access, skill requirements, and speed of fabrication all reduce the fun quite a bit. While the leap from bench vise to autoclave is a large one, if one can leap, there's no sense in taking baby steps. The solution that increases the probability of getting to the starting grid on time and finishing the race is the best one.


Having a screw loose has really interfered with getting any work done for a while now. That reduces the fun quite a bit as well. That screw, along with the rest of the hardware, is getting removed soon! Progress on the racer should happen a lot faster afterwards. Faster is always better. 


07 April update: Foot hardware has been removed. By the doctor, in case you were wondering.

See you at High Plains Raceway soon.... 

Sunday, July 19, 2015

My idea of fun...

While cornerworking in the 100 degree heat at a recent MRA race, a very radical two stroke concept crossed my mind, man. I can develop it from an existing engine while developing the next race bike. So I got another Kawasaki 500 engine.


More power with potential for a lot more power, a lot less weight (Goal: 265 lbs), a much narrower rider position (Much more aerodynamic and safer as well; the rider's squishy and crunchable bits go inboard the frame's perimeter this time), and a lot more traction with radial racing slicks instead of DOT bias ply tires all sound like my idea of fun. If all goes well, 2016 will see the current racer back on the track and construction started on the next racer. No idea what year it will be finished.  


The KX500 engine weighs 60 lbs, minus the radiator, carburetor, and exhaust. The EX500 engine, in the same configuration, weighs 126 lbs. The engines were weighed on the same calibrated scale. Both engine silhouettes above are the same scale and shown leveled with the output shafts in line. The length of the KX engine will increase when it gets a counterbalancer in front of the crankshaft. Only one pipe is required for the KX, but it sure is a lot larger and more complicated to make than the EX exhaust system! The power increase, as well as the improvement in sound quality, should be enjoyable.

By the way - ever compare a four stroke street bike wiring harness to two stroke race bike wiring harness? Wow! 

Motorcycle roadracing is dangerous. Making roadracing motorcycles from scratch introduces even more hazards! As much as I like titanium, I prefer to use as little as possible internally. Every precaution is being taken; no expense has been spared in the name of safety!


Wednesday, January 21, 2015

Looking back and running ahead...

There isn't much glory in finishing near the back and getting lapped, but I do learn a lot from the faster racers when that happens. And if you think watching racers from the stands or the return lane (Or better yet, while cornerworking!) is exciting, imagine the view from the track when they're just a few inches away! While I'm still optimistic about lowering my lap times and finishing better, I'll never get on the podium with this bike; that's for the next bike, and most likely, with a much better rider. Design work has started on the next racer.


Much of the design of the next racer depends on work that hasn't been done yet with the current racer. That new rear suspension system still needs finishing and installation. Crash damage still needs to be repaired. I'm still hoping to have it done before the end of the 2015. But my biggest source of enthusiasm and motivation is the next racer; the next racer has given me the confidence to make the current one worth the time, trouble, and expense. In the mean time, the door that leads from my desk to the shed has been upgraded to lower my house exit times by at least .2 seconds. No chatter problems, either.



I'm very happy to report that my foot is healing rapidly. The big goofy post-op boot has been off since early November. The crutches haven't been touched since the Christmas holidays. The cane only gets used on evenings of rougher days and to help make a point while yelling at kids to get off my lawn. I'm just left wondering if my right foot will still need a racing boot that's 3 sizes larger than my left foot. Either way, it would be a shame not to find out this year...

Top photo: Jim Browning, Rocky Mtn Photos

Tuesday, September 23, 2014

5 minutes of fame...

Discovery Canada's Daily Planet show ran their RoadWarriors segment on the racer project yesterday. It is a fun introduction to the project that was fun to make. Five minutes means that it isn't a PhD level vehicle dynamics video dissertation or season long bio-epic.

June 2015 update: If the above video links are off line, watch the Rohorn Racer segment here.

Sunday, August 31, 2014

Race #4


MRA Round 6 on Sunday 24 August at HPR, Colorado Class, started with a lot of enthusiasm. The first lap (From a dead stop) was my fastest lap, ever. And while I've finally been able to get my corner speeds up, (Mostly in Turn 1, where I've been able to slide it uneventfully a few times this month!), a much longer than anticipated slide on lap 3 told me I'm as close to the edge as I should get - time to get as smooth with that speed as I can make it!

My higher level of confidence got me going faster up Turn 7, where I knew I could make up some time. A little too much throttle and little too much lean angle/speed at the apex resulted in a lowside crash. My battle with gravity was a very easy one - it felt like I fell about 2 inches before I was completely on the ground. It was the battle with inertia that ended badly.

The footpeg broke when we hit the dirt, injuring my foot. NO injuries anywhere else. My helmet never hit the ground. The new isolated gas tank structure worked perfectly, even though the fairing is damaged.


This was going to be my last race of the season, but it didn't end the way I hoped. As bad as that feels sometimes, enough was learned to make the next racing season much safer and faster. Faster and safer is always good!

The day was made better by the HPR staff who got us back to the Rat Van, and fellow MRA racers, track marshals, and enthusiasts who helped us get the Rat Van loaded. And best of all, the support of my wife and family - without them, I wouldn't be sitting here feeling this good about it.

Top photo: Jim Browning, Rocky Mtn Photos

Race #3


The MRA Round 5 weekend was my my first time at HPR with the North Course configuration. I attended the 08 August HPR lapping day to get some North Course experience. After every lap, I thought I would have Turns 9A/B figured out, but the next time around would prove otherwise.

The Colorado Class race on 10 August went well enough. The final lap was my fastest and finished 13th out of 16. The bike behaved perfectly.


Sure, the racer was made for racing. But that doesn't keep it from being a very good conversation piece!

Last photo: Santiago Shirtz

Saturday, July 26, 2014

In the mean time...


A morning spent at HPR's open lapping day on 21 July was very encouraging. I don't have any numbers, but I feel even better about the direction my riding is going. Working on my riding has been frustratingly incremental, but it is far more satisfying than working on crash repairs. 

Round 5 plans at HPR: Afternoon lapping session, Friday, 08 August and Colorado Class, Sunday, 10 August. I will not be there at all that Saturday.


Progress on the new rear suspension continues! The rear hub in the above picture might look unusual, probably due to the larger than normal brake disc. If all goes well, it will be used for the 2015 racing season.

Monday, June 2, 2014

Race #2


The Colorado Class on Sunday, along with the rest of the day, went very well. Only placed 17th out of 18, but shaved 6 seconds off my best lap time, with my final lap being the fastest. The race start went a lot better. The race didn't feel like it was too long this time, which also meant that I remembered to use the headrest and had no neck strain trouble. Almost pulled out of the race when the left exhaust baffle started coming off, but I really didn't want to DNF, so I grabbed the baffle while at speed  between T3 and T4, twisted it tight, burnt my gloves pretty good, burnt my hand a little, but was able to finish. The baffle never moved before and technically shouldn't (Yes, it was safety wired), but it did, and it will get fixed so it can't happen again. I won't describe how and where that malfunction initially diverted my attention...


I'm still way too slow. But the long list of areas for improvement is getting easier to see and harder to resist. HPR is starting to feel like home - and that is a great feeling! I'm getting bored with my current pace and feel a lot better about: Getting my corner speeds up, not coasting up to my braking points ("It's like you're on final approach for landing in the corners!", one instructor said, and not in a complimentary way.), transitioning and driving through the chicane much more aggressively (Where the bike excels, but my nerve doesn't), working on my body positioning (I'm getting more comfortable moving around, but getting too comfortable about not moving enough), and better shifting technique (2 botched shifts can really rattle the concentration, but were probably caused by not concentrating enough in the first place). The tires picked up an awful lot of rubber at both ends, which means that they could be used a bit harder. Retreading one's own tires with the stickier bits of other racers' tires isn't a speed secret.


What I'm starting to refer to as Byers Syndrome (That coming down after the post-race high, where I get all resentful about my performance when driving home) was remedied by remembering that 6 second drop in lap times. Just think: If that can be repeated, I'll be competitive in ROR by the end of the 2015 season! Why, I might even be on the front of the official 2016 MRA T-shirt!! Isn't that great? No, that's delusional! Seriously though, getting into the 2:20s is now a goal I'm far more optimistic about for 2014 - something I was despairing about while approaching Byers the last time/first time. And 2014 is just prep for 2015. The EXperimental500 will make a lot more sense by then.


OK - this site is supposed to be about the development of the racer project, but until the new rear suspension is done, the most important project is developing the biodegradable guidance unit. But while this bike was getting built, there was never any doubt who was going to test ride and race it. Nobody has ever said: "Hey, I just built this roadracer that violates all design conventions, has an unproven front suspension with unproven steering geometry, and places the rider in an unfamiliar position, but while my mental test rider likes it, I don't know if it will work in the real world or will become unrideable at certain speeds and lean angles - would you like to have a go on it?" 92 laps later, I'm very happy with that hardware, enough to know that a vastly better rider should get vastly better results. So when an MRA multiple champion comes up and says that he'd like to have a go on it after the race, well, that made my day. Not sure when it will happen - or if he'll like it and offer to race it, or point and laugh afterwards - but that is a monumental step forward.


While this isn't a secret website about a secret project, I don't promote it much outside of forum signatures or Facebook, either. That made an unexpected call from Discovery Channel a very pleasant surprise. They expressed an interest in videographing the racer and other projects both at home and the track, which was a real honor! No details yet, but will post them when they become available. Round 2 photographs are easy to spot from the cluster of Go Pro video cameras they mounted on the racer!


I used to joke that the real work involved with this project was going to start after the racer was finished. It isn't a joke anymore! So many years of dreaming/making stuff/testing (Repeat) went into this that I can't believe this is actually happening! It also wouldn't happen without the support of my wife, children, family, friends, everyone in the MRA, and so many more. Thank You!!!

Photos 1-4: Margaret Oliver, Colorado Photosports
Photos 5-6: Jim Browning, Rocky Mtn Photos

Sunday, May 11, 2014

Race #1

My goals for the MRA Round 1 race weekend were to finish the race, learn as much as possible for the next race, and best of all, finish ahead of at least one racer. In the first of two races I entered (LW GP class), all three goals were reached: 24th out of 25. The second race I entered (Colorado class), where the racer fits in a lot better, was cancelled due to snow (No kidding!).


The bike is still better than I am. I'm still rolling off the throttle too early, braking too soon, and apexing the corners too slow. But I am trail braking less to the apex and rolling on the throttle both earlier and more than before, which is helping the bike track better and making the tires wear more evenly. Speaking of tires, my choice of rims (Hey, they were free) limits me to Dunlop GT501s. They sure aren't race tires, but they are sticking  better than I expected. Neither end slid the entire race by intent or mistake. The bike has the potential to go faster.


The bike launches like nothing I've ridden. Unfortunately, that doesn't do much good from the back of the grid when I'm not sure which line everyone else is taking into T1. Playing skittles with the other racers makes for amusing video but is generally frowned upon by both the racers and the starting line marshalls. Whenever I can work my way ahead in the start grid, hard launches should be a lot of fun!


After the (Dismal) start, I had a blast blowing past people on the back straight. After that, it was obvious that the better skilled riders (22 of them...) were faster into the corners, where the speed really matters. I was more interested in crossing the finish line safely than being a rolling roadblock, so I "Settled down" and somehow managed to drop my lap times for each lap...until the red flag came out. The cooldown lap was surreal after that, followed by cruising back to the pit with lots of waves, thumbs up, and enthusiasm! Nothing like the post-race high while loading everything back into the Rat Van and heading back to Denver while replaying the thrill of racing in your head! And then somewhere near Byers, thoughts about all the mistakes, hesitations, and misjudgements take over! Well, I've since found out that is typical Racing On The Brain syndrome and it all balances out before the race weekend. It's why we go back to the track. Round 2, May 31/June 01.


Oh yes - as far as anyone knows, this is the first recumbent (Or Feet Forward, as my British friends call them) roadracer ever entered in a sanctioned roadrace. Thank you for all the support and patience from family, friends, and fellow enthusiasts!


Photos 1-3: Margaret Oliver, Colorado Photosports. Photos 4-5: Jim Browning, Rocky Mtn Photos.

Monday, April 28, 2014

Forward Thinking Friends...

While the racer has a much lower frontal area than a stock EX500, it still has a Cd range in common with farm implements. Streamlining could seriously add to the acceleration on the faster sections of the track without making any changes to the engine. But that isn't news, especially to Craig Vetter, who recently PhotoShopped streamlined bodywork on the racer.


Read more about it on Craig Vetter's website.

So when will that happen? Not this year. Approaching the corners even faster than I am now would not help my lap times at all, but that'll change with experience. And I am very optimistic about what a combination of experience, superior aerodynamics, and the new rear suspension (Currently being machined and fabricated) will do for improving lap times in 2015! And after that comes the really exotic racer! 


But first, there's the 2014 racing season, with the bike as it is. It isn't slowing me down; I'm slowing it down. The solution? Track time! 

I've never had more fun in my life...

Monday, April 21, 2014

Racing Season Is Here!

 
The MRA's race school was held on 19 April. After running about 40 or so laps over the course of the day, I got my racing certificate.


The first event is at High Plains Raceway, 10-11 May. I'm registered to enter the Lightweight GrandPrix and Colorado Class.


During the racer school, someone asked me the bike's name. It never got one! Well, it's been given a few (Just ask the MRA's New Rider Director...), but it needed one for the race registration that I'd also want to say out loud: Kawasaki EXperimental500.


Photos: Jim Browning, Rocky Mtn Photos.

Monday, December 2, 2013

Is it summer yet?

See you at High Plains Raceway in 2014!


28 December: Got to ride it at HPR during their "Customer Appreciation Day" today - everything went very well! Only ran about 13 laps, but it was enough to get more experience and reveal what I need to work on next time out. Smoother corner entrances resulted in higher cornering speeds, less panic, and earlier drives out. I also discovered that this bike, like any other, responds well to body positioning (And poorly to bad positioning, such as leaning the shoulders the wrong way to keep my head level when cranked over), but this one doesn't need nearly as much gymnastics to make the handling more neutral while cornering. When your butt is just over a foot off the ground, the idea of getting it even closer (Especially to the curbing!) seems just wrong at first, but the way it improves the handling inspires loads more confidence. The speeds are up to the mid '90's between turns 3 and 4; when you're that close to the ground, the sensation of speed feels absolutely insane. But as exciting as that has been so far, that speed is still too slow and uncompetitive for a 500 twin. The good news is that we'll go a lot faster with higher turn 3 exit speeds and later braking before turn 4. So far, I've been braking way too early for, well, all the turns, but that'll change!


Sorry, no lap times and no video, yet.