<50 mph: 6040 RPM"content-type" content="text/html;charset=ISO-8859-1"> Freedom Machine - Fuel Economy -Chap 34
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. 34: 80 mph! 84 mpg! April 25, 2010
The formula for living better on less energy

Streamline it, slow the engine down so it produces less power.

The head winds
The results
I knew as soon as I saw 1 1/2 gallons was used to go 133 miles that we were finally getting the results I have been working so hard for. My goal is to get 100 mpg, at 70 mph, into a 30 mph headwind, carry 4 bags of groceries and be the first choice of vehicles in a garage full of great machines.

I call these "Vetter Conditions"

Lets review the history of this venture:
2008: I began with a stock, 17 hp Honda Helix. On a still day, it might get to 72 mph. It generally got 62 mpg. But, not in "Vetter Conditions" because it is not streamlined.
2009: Fully streamlined, it would now easily go 75 mph and get 64 mpg in the "Vetter Conditions" above. I love the storage capacity. But sidewinds moved it more than I wanted.
2010: The inflatable tail has been replaced with a plastic tail. The sides are open to let sidewinds pass thru. The windshield is now attached to the handlebars. Prius car headlights fit the streamline shape better and point in the right direction. Gears from Jan Vos of Belgium slow the engine down by 20%.
The engine has not been modified. All changes are due to streamlining and gearing. I notice that it is a little slower off the line... for the first 10 feet or so. The slow acceleration is especially noticeable if I am starting up hill. We have a steep hill on Highway 1. Previously, if I accelerated onto its on-ramp, I could get to 65 mph by a certain overpass. It still does it with the new gears.

It used to climb 12% Laureles Grade, at 50 mph. Now it does it at 45 mph. Fortunately, most cars cannot go any faster.

At the end of the day, the geared-up, streamlined Helix gave me 84 mpg!

Remember, this is my first time out with the new gearing... my first and only run. The machine is rough and unfinished. But I am very encouraged.

I am now riding normal, errand-running. We will see what happens in "Stop and Go" riding. I'd bet mileage is better than before. We will know soon. The machine feels so much better with the engine running slower.

Mileage posted June 8, 2010:

May 6, 2010 Quail Gathering road ride: 142 miles, 1/2 in mountains @50 mph, 1/2 into a 30 mph headwind @70 mph, 3 fast laps around Laguna Seca: 90.9 mpg

May 25, 2010 Running errands around town. Lotsa stop & go: 64.8 mpg

May 29, 2010: Running errands, a little more high speed: 69.9 mpg

I do not drive to save gas. I accelerate fast. I go the speed limit or a few mph faster, figuring my speedo lies. Only streamlining and the resulting engine gearing has changed.

The faster I go with the fewer stops, the better the mileage

I love headwinds. I simply do not feel them!

Basic Helix Review:

17.33 horsepower @ 7500 rpm or  12.92 kilowatts

At the 2010 Iron Butt Convention, I met a man who said his Helix on a dynomometer put out 13 1/2 hp at the rear wheel. This helps.

15.16 foot lbs torque @ 5,000 rpm or 20.56 Newton Meters

Below are the readings from my digital tach:

Stock Gearing:

50 mph: 6040 RPM

55 mph: 6640 RPM

60 mph: 7200 RPM

65 mph: 7800 RPM

70 mph: 8400 RPM

75 mph: 9200 RPM

New Jan Vos Gearing:

50 mph: 5200 RPM

55 mph: RPM

60 mph: 5800 RPM

65 mph: 6060 RPM

70 mph: 6640 RPM

75 mph: RPM

80 mph: 8000 RPM

It won't go faster than 81 mph. This is probably because max horsepower is at 7,500 rpm. It has less horsepower at 8,000 rpm... not enough to push it into a 30 mph headwind past 81 mph.
Page posted April 25, 2010

Updated Aug 17, 2010

Chap. 3: Road Testing the Long Tail Mar 28, 08
Chap. 1: Streamlining Saves Fuel Feb 20, 08
Chap.2: CAD Streamlined Body Mar 8, 08
Chap. 4: Planking with Foam Apl. 5, 09
Chap. 5: More Wind Testing Apl. 7, 08
Chap. 6: The Final Shape Apl. 17, 08
Chap. 7: Decisions about Details May 10, 08
Page 8: Making the Center Bulkhead June 1, 08
Chap. 9: Rear Bulkhead and Truck bed June 8, 08
Chap. 10: Finish Rear and go for ride June 17, 08

If you have not yet watched my DVD, How they Got 470 mpg it is time to get it for the basic foundation for what we are doing here

Chap. 11: Finish the Tail June 29, 08
Chap. 12: Heading for Ohio, July 13-23, 08
Introduction to Fuel Economy
Chap. 13: Riding in the Midwest July 24, 08
Chap. 14: Vintage Days Ohio, July 25-7, 08
Chap. 15: Summary to date Aug 12, 08
Chap. 16: Adding Weight to the Front Sep. 1, 08
Chap. 17: Truth and Motorcycle Design Sep 4, 08
Chap. 18: Where should the weight be? Sep 25, 08
Chapter 19: Finishing the Streamlining Oct 14, 08
Chapter 20: Streamlining the Handlebars Nov 4, 08
Chapter 21: Unexpected Problems Nov 11, 08
Chapter 23: Getting my feet in and out Dec 19, 08
Chapter 22: Streamlining is working Nov 25, 08
Chapter 24: Streamlining is beginning to work! Jan 1, 09
Chapter 25: Tuft Testing Mar 2, 2009
Chapter 26: Starting Over April 9, 09
Chapter 27: More Ideas for Starting over April 20, 09
Chapter 28: Show time! Aug 1, 2009
Chapter 29: Getting the big parts right Dec 10, 2009
Chapter 30: First evaluation from an outsider Dec 20, 2009
Chapter 31: Visit with Allert Jacobs Dec 24, 2009
Chapter 32: Prius Headlights Jan 18, 2010
Chapter 33: New Gears Feb 17, 2010
Chapter 34: New Mileage Records April 25, 2010
Chapter 35: The Quail Gathering of Motorcycles May 9, 2010
Chapter 36: End of the line with the Helix June 19, 2010
Chapter 37: Vetter Challenge Oct. 9, 2010
Chapter 38: John Keogh helps out Dec 8, 2010
Chapter 39: Working with Keogh Dec 17, 2010
Chapter 40 and up (Work continuing in 2011)
Designing the Last Vetter Fairing

Chapters 1 thru 39 (2007-2010)

Chapters: 40 thru 51 (2011)

Chapters: 52 thru 61 (2012)

Chapters 62 thru 68 (2013)

Chapters 69-up (2014)

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