The Search for Fuel Economy

Pages from a Designers' Notebook

Freedom Machine
The goal: 100 mpg at 70 mph, into a 30 mph headwind, with four bags of groceries.
Chap. 36: The Truth
17 hp Honda Helix

Only the streamlining has been added

17 hp Honda CRF 230

Only the streamlining has been added

We met in Gilroy, CA and planned our route. We needed headwinds. Strong headwinds. The winds were pretty strong from the west and south. We decided to head south on Highway 101 with the speedo indicating 70-72 mph. Alan said that he could get 100 mpg. Yeah... lots of people say that. But in the "Vetter conditions"?

"70 mph, into a 30 mph headwind with 4 bags of groceries, sitting up, comfortable"

First, we needed to do a little equipment check:

Full lock turning on the Vetter machine... a little restricted on the Smith streamliner.

Full turning is difficult with streamlining. But full lock travel is important in maneuvering.

Storage for 4 bags in the Vetter machine... a little restricted in the Smith streamliner.

I had just made a new windshield with an air intake at the front. Alan had just bolted a piece of plywood on as his first windshield. Both machines are a work in process.

The new air intake is intended to let air in to fill the inside where I sit. This allows the wind to slip around me easier. It also gives me some fresh air on my face which I like.

This was going to be a very informative day

I want to start over with bigger wheels and better suspension. If Alan's CRF performs as he says, it could be my next machine. We topped off our tanks and headed south on Highway 101 to King City and good Mexican food. We could expect light tail winds at the beginning, becoming stronger as we approached our destination. The real "telling part" part would be returning into the wind.

I set the pace on my Helix, accelerating rapidly to 70-72 mph. To my amazement, Alan stayed right with me. My son, Zak, on his KLR, said my indicated 70 mph was 71. Alan said it was 69 on his CRF. Close enough.

50 miles into the trip, we stopped to review things and get an apple fritter. Zak went ahead to set up and film us as we passed by. Alan and I decided to do a little drag race after the ramp onto 101. I let him go first and - surprise! He motored away from me. Slowly... very slowly, I was catching him. My Helix tops out at 81-82 mph because of the streamlining and Jan Vos' gears. Alan's CRF is similarly re-sprocketed. But his top speed is a tad less than mine. With a good tail wind, I figure this means we have about the same gearing and horsepower.

This CRF is looking better and better!

At King City, the wind had become a very strong tailwind. We filled up with regular gas. After 80 miles:
Craig consumed:

.975 gallons = 82.05 mpg

Alan consumed:

.898 gallons = 89.08 mpg

I had expected better. After all...

"Anybody can burn less fuel down wind (or down hill)"

The real test would be into the wind. The trip back was shorter, 46 miles, terminating in Salinas. It was all into the notorious, afternoon headwinds of Salinas Valley. "Maddening and scary" is my best description. Local motorcyclists know to stay off Highway 101 heading north in the afternoon.

I was pretty sure my Helix would do better than Alan's CFR into the wind. The two machines seem to be equal. But the streamlining on my Helix is more developed. I sit lower and I have a smaller frontal area.

I was right. As Alan and I accelerated on 101, it became clear that he could not go 70 mph into the fierce headwind. I just left my throttle on and it kept accelerating to 78 mph where my Helix topped out.

Alan disappeared in my rear view mirror.

This was very satisfying.

I kept an eye on my temp gauge but it stayed normal. After a while, I felt sorry for Alan and slowed down to let him catch up. He had discovered that if he bent his plywood windshield down, he could run 70 mph, too.

Indicated 104 mph wind coming at us

I carry a little hand held wind meter. At 70 mph indicated, my wind meter thought the wind was blowing at 104 mph! That is a 34 mph headwind! Definitely a good day to test. Sticking my head out wanted to rip my helmet off my head. I almost lost my sun glasses!

46 miles of this was enough for us.

See what it was like. 1 minute 49 second .mov of Alan and me

46 miles later, into awful headwinds, we refilled in Salinas:

Craig consumed:

.661 gallons = 69.59 mpg

Alan consumed:

.765 gallons = 60.13 mpg

Compare this to a similar Ride Jan 1, 2009.

A stock Helix can only go 65 mph into a 30 mph headwind. It gets 53 mpg.

My geared up, streamlined Helix will go 78 mpg into the 30 mph headwind. It will easily cruise at 70 mph. It gets 69 mpg at 70 mph into the 30 mph headwind.

65 mph vs 78 mph top speed!

53 mpg vs 69 mpg!

Streamlining makes a huge difference! We are making progress.

So, who won the challenge? Neither one of us got 100 mpg at 70 mph into a 30 mph headwind. But we did pretty good... probably better than anybody in the world.

I am sold on the viability of the Honda CRF. It performs pretty much like Alan Smith said.

Here is Alan's take on the day:

"I had a great ride with you Saturday. I’m glad that I pursued my CRF230L streamliner project. My streamliner project showed me that it is not that simple to get 100 Miles-Per-Gallon, good performance, and still be easy to ride. It is too bad that more work in the motorcycle industry is not being done to clean up the aerodynamics of motorcycles.

Before we got together for our friendly competition I was a little concerned that my streamliner would not perform up to what I had talked about. Saturday’s ride with you pushed my streamliner much harder than I usually ride.

The cooling modifications that were made in the last few weeks worked perfectly. My air cooled engine actually ran cooler when I was riding into the strong afternoon head winds with a full throttle than with a tail wind and quarter throttle.

My new windshield finally gave me the protection that streamliners are supposed to do. Now I don’t have any perception of speed because I don’t feel the headwind. I have to be careful not to go over the speed limit. During Saturday’s ride I found that I need to do more work on my new windshield because it has to much drag and lowered my gas mileage. It needs to be trimmed and reshaped.

Saturday’s ride showed that both of our streamliners could cruise in comfort and still get great gas mileage. Crosswinds seem to be the nemesis for streamliners. During one section of the ride we both got bounced pretty hard with the 35 MPH headwind and crosswind gusts. I’ve got some ideas that I want to pursue to solve this problem.

I would say that our friendly head-to-head gas mileage competition was very informative. At the end of the day we both had big smiles. Your Honda Helix streamliner performed much better in the afternoon headwinds than mine."

Thank you, Alan Smith for helping to make motorcycle history.

My Motorcycle Design Dilemma
It is generally believed that a KLR is pretty good for all-round riding. It does everything. But my Streamlined Helix has become my first choice in machines to actually ride. Really, I would rather take it anywhere... to the grocery store.. to Big Sur... to Alaska. It has built-in storage way beyond any motorcycle. I just throw stuff into the enormous space its streamlining naturally provides. No saddlebags flapping in the wind.

The streamlined Helix "Freedom Machine" is more comfortable. It is much easier to get on and off. The seat pad is huge! My bottom never hurts. The ride at 70 mph is quiet. I do not need ear plugs. It has enough power. My son, Zak said the KLR topped out at 86 mph into the 34 mph headwinds. My streamlined Helix would go 78 mph into those winds. Isn't that fast enough?

I don't think we can really streamline a standard bike like a KLR - or a CRF for that matter. The seats are too high on standard motorcycles. For streamlining, lower is better because it reduces frontal area. Reduced frontal area means less drag. Reduced frontal area means less side area for the winds to push on. In the movie above, you can see that Alan blew around more than me. He is higher because his seat is higher.

The dilemma is: Do I finish the Alcan Fairing for motorcycles that are never likely to get 100 mpg? Or, do I finish the "Last" Vetter Fairing which has the possibility of helping to get 100 miles per gallon? A quantum improvement can go a long way to reducing our nation's thirst for imported oil.

Review the Second Gathering of Streamliners at 2010 Mid Ohio Vintage Days

Master Index to the Last Vetter Fairing Story

Page posted June 19, 2010

Updated August 17, 2010