TONY'S RECUMBENT HPV PAGE

 

  I built a long wheel base recumbent from old bike parts in 1983 after seeing an Infinity on the bike trail. The seat was 10 inches off the ground and a nearly vertical seat back. I also built a mwb from conuit and a rear steered unrideable bike. I had no idea that other people built these bikes until I saw the WISIL group one day at the Elgin Library parking lot in 1996. I went to the MnHPV club meetings for something to do when I was working in Minnesota for a year in 2001. The next bike I built was in spring 2001. It was a space frame design from 1/2 inch conduit. The frame was too stiff vertically and torsionally flimsy. I rode it around Minneapolis and raced it once. The bottom bracket was 35 inches off the ground and the seat 20 inches. It was hard to get one's foot up on the petals. When I get time to scan the photos in I will add the to the web page.

Home built recumbent HPV. 27 x 1.25 inch wheels, the HBS27

  I built the HBS27 bike in September 2001. I rode it allot on the trials around Minneapolis. The Luce Line was my favorite, riding to Water Town and back. This bike has some features, the front wheel is too big and there is heel interference. The long tiller makes the bike unstable at low speeds and unpredictable in soft gravel, the petals are too high and starting is difficult. Only one other person was able to ride it. Needless to say I have several uncontrolled landings in the 2000 miles I rode it. Once going the bike is fairly comfortable and has good aerodynamics. Watch out for horses on the trail! I've been kick at twice on the Prairie Path, landing on my butt in the ditch. They get spooked. Now I stop and let them go by. I raced this bike in Indianapolis, but did not do so well. I nearly crashed on the start of the drags, but amazingly pulled it out.

Click here for streaming mpeg video of a fast pass.
 

A long wheel base the LONG RIDER 220.

  Ed Gin called it a long rider during the sprints and 220 was my race number. The suspension shown in the picture made the frame wobbly, and was abandoned. I raced the bike with a tail fairing successfully at the Tucker 100 and in Kenosha. I was fourth and second place in my class. This bike has an 81 inch wheel base and is faster then my previous swb bike. The tail box and low profile makes a difference.  I have ridden it to work 3 times, 70 miles round trip. I rode it 100 miles one Sunday on the crushed limestone trails, the long wheel base is stable at speed. When I am going slow, usually uphill, people laugh. When I am going fast I get "cool or tight bike" comments. Riders say they can't get a good draft behind me. The frame is 2 3/8 diameter by .058 wall mild steel tubing (chain link fence tubing). The steel is soft and I have welded up fatigue cracks near some welds under the seat. 

width=345>Warren passes the pack on the outside in the Barracuda

The bike gets a front fairing, 550 mm short low Q cranks, clip less petals, chain steering, 7 speed cog, and aero wheels for the 2003 races. Speed improves. Horses seem to be OK with this faired bike. Maybe they don’t see feet pedaling up in the air. I can make it 40 miles to work in 2.5 hours. It flies on slight down hills on the crushed limestone trails, leaving the mountain bikers far behind.

     

VEHICAL DESIGN:

Laminar flow bodies:

Papers:

Effect of nose width on laminar flow - narrower is better up to a point
Theoretical optimal laminar bodies based on Reynolds Number.

More on laminar flow

Low Q crank:

The crank is a modified BMX cotterless 3 piece with American style bottom bracket. The American style has much larger bearings, and thus can be closer together with the cranking moment reacted across a larger diameter. I cut and welded the axel and bottom bracket.  The Q is 3.75 inches measured outside to outside of the arms. The bottom bracket is 1.5 inches wide. The 2 main limiting factors are tube diameter and chain and chainwheel clearance. The frame tube has been recessed in this area. The cheap steel crank arms have been cut about 1 inch shorter. Aluminum arms would be lighter. The crank allows a smaller and lower fairing.

New for 2004:

Manuverability is a key attribute that will be addressed on the new bike. Sometimes in The Carp I found myself having to get out and pick the bike up to turn around. The steering was limited to less than 45 degrees. The wheel base is shortened from 81 to 72 inches and a 20 (406) inch front wheel allows plus minus 90 degrees rotation. I am thinking of replacing the cable steering with a linkage to reduce Q interferance, but this may limit the angle unless the ball joints are placed above. The rear suspension feels good over bumps on Initial coasting tests. The suspensiion makes the height adjustable over a 10 inch range. Higher seating and more layed back position results in the furthest coasting distance. I used ball joint rod ends as the pivots of a trussed swingarm. This was a mistake because they have no torsinal stiffness, thus the moments are reacted by normal forces through the balls. The torsinal compliance of the ball joint to swingarm connection makes the bike wobblely. A large diameter close clearance concentric tubes would be better, like Warren's Street Cuda pivot. When adjusting the seat hight, the head tube angle changes. Small or no head tube angle makes the bike "hunt". Larger head tubes and caster are better at speed, but make low speed manuverability harder, due do wheel flop and increased steering effort.

Tony

The WISIL HPV link