1984 Craig Vetter High Mileage Contest
Laguna Seca GP, Monterrey, CA
Building, Testing, and Competing in a Motorcycle "Full-Streamliner" - Page 1
Page 2 - More on Streamlining and Lessons Learned
Background:
From 1980-1985, Craig Vetter, the inventor of the first useful and popular street motorcycle fairings, held a really cool high mileage contest for motorcycles at the Laguna Seca GP. I decided to enter the competition in 1984 and use it for a senior project for my BSME degree at CSU, Fresno.
The contest was really cool! It was also practical. This was not some silly demo where you roll around at 20mph in a parking lot and coast to a stop. Qualifying required that you ride your mileage bike on Highway 1 along the California coast near Big Sur, and you had to at least average 55mph, in traffic. Additionally, the bike had to be street legal, including working turn signals and legal mirrors. This was a scary ride. The road had non-stop tight turns, violent crosswinds, and the cost of a mistake could easily mean going off a steep cliff you could not even see the bottom of from the road.
This page is put together in honor of the return of Vetter's mileage contests! On July 22, 2011, the AMA Vintage Motorcycle Days will feature the "Vetter Fuel Economy Challenge." There is even a new class for electric bikes.
On this page, I want to pass on what I learned about building and competing on a full streamliner, tell some funny stories, and talk about what participating did to help me with human-powered vehicle design, which I was doing at the time. I'll do my best to pass on some useful tips to anyone who is into designing streamliners or partial streamliners.
The 1984 Fresno Yamaha Streamliner:
When I heard about Vetter's mileage rallies, I was busy at CSU, Fresno (Fresno State for sports fans) in the engineering school's ASME chapter. We were experimenting with different HPV (Human Powered Vehicle) designs for racing. We raced other colleges under ASME, and went to the IHPVA international championships as well. I was on the HPV project for a few years and ended up leading it for a while.
I saw some of the previous Vetter rally's top bikes, and I was impressed. People were getting well over 300 mpg. Fuel prices were high (sound familiar?) and magazines and OEMs started showing interest in radical ideas. Motorcyclist magazine ran a feature about Matt Guzzetta riding coast-to-coast in a Suzuki 125 streamliner on one tank of gas! (It was a big tank, but still!)
I wanted in. I talked to Fresno Yamaha about it and they agreed to loan me an SR185 for the summer break, long enough to build something and enter it in the 1984 rally. The constraint was that I had to return the bike in new condition, so it could be sold as a demo. That meant no chopping the frame or grinding on engine parts. I was going up against experts with years of experience and no constraints. I decided that it would be nice to find a strategy to win, but even qualifying for Sunday to ride it in front of 80,000+ people at the GP would be a success.
Strategy:
A Full Streamliner
Since I would not be able to do radical changes to the bike, I decided instead to go for "full" streamlining, to get aerodynamic drag to the absolute minimum and just make the best of it.
Here's our human-powered full streamliner we took to the IHPVA world championships. The photo was taken at the Indy 500 Speedway. The fairing is made from a plaster plug, which we used to make a fiberglass mold from, then we made a thin Kevlar fairing. Very trick! This makes really nice fairings, but it's labor intensive, and expensive.
Here's what I ended up with for the Fresno Yamaha Streamliner. It's model airplane Mylar stretched over cedar strips. My girlfriend was going to make a cedar strip canoe, but this is where it ended up. Notice the gull-wing door and flush turn signals. I took my chances and only made a door on the left side, and a tiny foot door for the right.
Before we get to the fairing in detail, a few other things-
Other Mods:
I could not chop the frame or convert the thing to a recumbant because I had to return it, but I still wanted to lower frontal area. This had to be worked out before drawing up the fairing shape so I could see how low I could tuck in. I took off the stock bars and had two custom clip-on handlebars made that clamped to the fork just below the bottom of the triple clamp. CSU Fresno's machine shop custom made the clip-ons.
I took the stock seat off and just taped on a piece of foam to sit on, about like that stuff that is used to wrap pipes.
I knew that re-gearing would help to take advantage of lower drag, but changing the gearing was a guess. Yamaha didn't have radically different sprockets, and messing around inside the motor would be impractical.
I went to a local industrial bearing store and found a chain that is about like a motorcycle 420 chain. They also had sprockets. I picked the smallest rear sprocket that I thought I could get on the rear wheel without it rubbing on anything. All it needed was some holes drilled and some machining. Easy stuff for CSU Fresno's machine shop.
The front sprocket was the largest one I could fit on the motor without the chain rubbing on the case. The problem was these sprockets don't have splines in the ID, just a hole. Also, front sprockets have a lot more hardness. Cutting splines takes a fancy broach tool (and money). I ended up taking a motorcycle sprocket and the one I wanted to make, clamping them together with two vise-grips, and I filed the splines by hand, using the motorcycle sprocket as a template. It worked!
I knew this was "hick engineering" but it's not like this thing was going on a 1,000 mile journey. It only had to make one Vetter Rally.
Making the Fairing:
One of the first fully-streamlined HPVs that our AMSE club experimented with was a prone recumbant with a full-length Mylar fairing, made from the same heat-shrink Mylar used for model airplanes. All you need to do is stick the Mylar on, and hit it with a heat gun and it shrinks tight. It weighs about nothing, but its fragile. For a one-off event, it gets the job done. You want to avoid peaks and valleys in the direction of travel to minimize air separation (more on this later).
I was under time pressure to get this thing built before the rally, so this was a quick way to get done.
Once I knew about how low I could tuck in after removing the seat and using the clip-on bars, I drew up a 2-D profile in the shape you see above.
I made a nose cone out of expanding foam and carved it to shape. Then I made three oval cutouts out of plywood to match the height and width in three places-one just in front of the front wheel, one about where the gas cap was, and the other about where the back of the seat was. I cut out the inside of the plywood ovals so they would fit over the bike, and bolted them on using aluminum strips.
Then I jabbed the cedar strips one-by-one into the foam nose cone and stretched them over the cutouts to the rear. The trailing edge was just a straight piece of cedar strip.
Then I took about a 1/2" wide piece of nylon rope, and tied it on the inside to space the strips. The rope sections were curved inward so they wouldn't cause peaks and valleys once the Mylar was stretched over. You can still see them in the various pics. The last steps were to soak the rope in polyester to make it hard, then take away the plywood cutouts, then apply the Mylar and heat shrink it to make it smooth. It worked!
Notice the cedar strips are held in place by curved nylon rope, hardened by soaking them in polyester resin after they were in place.
Testing Day:
I only had one day to test this thing before making the trip to Monterrey for the contest. I was anxious to see what kind of mileage it would get. Compared to the other vehicles in the contest, I was at a disadvantage due to the bike's large size. The frontal area was high, and drag is directly proportional to drag coefficient times frontal area (CdA). I was hoping that the full streamlining would make up for it, since the other vehicles I saw from previous events had openings in the fairings, which cause separation and raise Cd.
I was lucky to find a clear, flat road north of Fresno, on a calm day. I got an honest 200 mpg on it, and at 55mph, it was literally idling in high gear. The gearing changes I guessed at would be just fine.
The Trip From Hell:
A buddy of mine that saw this thing coming together really wanted to go along, and I talked my awesome girlfriend Grace into going too. We got the streamliner and his street bike stuffed into the back of my Toyota longbed the night before qualifying in Monterrey. We would have to drive all night to make it. Sheesh!
My truck had a slipping clutch, but it would have to do. We piled in and took off, even though Grace was not too happy about sitting between the seats in the tiny truck cab.
I couldn't stay awake, so my friend got us there. I told him to go easy on the clutch, but noooo. When I woke up we were nearly in Monterrey, but DNF'd on he side of the freeway. The truck would hardly go. I think we even had to get a tow to a junkyard, find a used clutch, and get towed to make the event on time! Hey, no big deal. Why does Grace still call this "the trip from hell!?"
In addition to a fried clutch, much of the Mylar had blown off the back section and the top. There was no time to fix it. I would have to qualify with some of it missing. The gull-wing door on the left side was too damaged, so I had to take it off, making the streamliner even that much more dangerous.
The deal was you had to drive at least 55mph on the average along the coast on highway 1 to Big Sur-about 30 min south, turn around, and 30 min back.
My friend rode alongside, and Grace was on the back of his bike and snapped this photo during the ride to Big Sur.
The Scariest Motorcycle Ride of My Life:
If you ever get a chance to try out a one-off, never-tested streamliner on a curvy-windy road-SAY NO!
It was all I could do to hang on to this thing and finish. The crosswinds were intense, and due to the terrain, they would alternate from side to side. It was made worse because much of the Mylar was missing, so the strong winds would grab the bike so much it felt like someone was on the outside trying to push me to the ground. Then it would ease up, then hit from the other side, sometimes rapidly. It was like being trapped inside while people on either side were pushing it back and forth as fast and as hard as they could, except I was trying to maintain the 55 mph minimum too. Gee, thanks Craig!
Sometimes I was literally leaning way off the bike with my shoulder against the fairing pushing back, like I was leaned into a corner...but this was just to keep it straight! To add to this, a mistake could have been fatal. The cliffs come right up to the edge of the road, and in some places they are steep and you can't even see how far down the bottom is.
I really should have quit. It was unsafe, no doubt about it. But, after a couple of months of work and driving all night, quitting was not an option. I was going to still try and qualify for the main event-the mileage rally in front of 80,000 people at the GP the next day.
I made it! Even with much of the Mylar missing, I still got 145 mpg, and qualified for Sunday.
Now we had to find some more Mylar and a shop to get my clutch replaced. I don't know how we pulled it off, but soon I was at gas station that agreed to put the used clutch in, and I was out back with my heat gun putting Mylar back on the Fresno Yamaha Streamliner for the next day. Grace become more convinced that this really was the trip from hell.
Sunday:
We made it to the pit entrance Sunday on time, and Vetter himself was making sure security was letting his contestants in. I remember him saying "Wow, you fixed it! Looks great." I get directed to where to park and line up with the others that qualified.
The star is Dan Hannebrink with about a Honda 80, which is a low-to-the ground recumbant. Another favorite is Charly Perethian of Rifle Fairings, a past winner, another entry with a clone of Perethian's Rifle, Honda R&D, and Suzuki's entry-the streamliner Matt Guzzetta had riden coast-to-coast on. Yikes! Tough competition.
Vetter also has a famous engineer on hand, Doug Malewicki, who I first met at an IHPVA conference on human power. Malewicki made a funny trophy with a big screw through a gas pump, and he made a point to talk to everyone about what they did and what decisions they made. I remember Malewicki really checking out the way the Fresno Yamaha Streamliner structure was just rope hardened with polyester resin. If you haven't heard of Malewicki, take a minute to read his amazing website.
The deal was that at halftime at the GP, we would drain our carburetors, keep some fuel in the tank, and everyone got a ketchup bottle with 3 cents worth of gas in it. Vetter would follow and make sure everyone went at least 55, so no one would try and win by crawling (and boring everyone).
Off we go. I wish we could have had some practice. I made it around a lap but was trying to conserve too much and ended up with Vetter beeping at my butt to hurry up and get up a long uphill. I had to gas it. With 3 cents worth of gas to work with, you don't want to do that. That's what I get for being a rookie. Hannebrink's luck was worse. He should have won, but his gas ended up on the ground at the start.
I think I made 2 laps, and we were to pull over and wait until everyone finished, then use our gas in the tank to get back.
Here I sit at trackside, with thousands of people, and I'm thinking "Hey these people probably think we are the coolest." Just then I hear a spectator go "Get the F*** off the track! Bring on the racing!"
This is getting a bit long, so continue on to Page 2 for a discussion of spinoffs, more about streamlining, and lessons learned.
This is the gold-medal winning "World's Fastest Mountain Bike," a direct spinoff of participating in the 1984 Craig Vetter High Mileage Contest. (See Page 2)
Here's a pic I never saw that Vetter emailed me today. This is after the trip to get there. Notice the Mylar is still missing on the top and the back. You can also see the little foot door I made instead of a second gullwing door. I patched it up for the main Sunday with Mylar from a hobby shop..
From Vetter's site-
I got 7th! All these years I thought I had 9th, because I think Cycle News got the results wrong.
Did I mention that there is a Page 2? |
