IHPVA NEWSVolume 2 Number 2

Spring 1983Published occasionally by the IHPVA for itsmembers and others interested in promotingimprovement, innovation and creativity inthe design and development of human-powered vehicles as well as encouragingpublic interest in physical fitness and goodhealth through exercise.

Richard L. Hargrave, Editor andArt Director

Chuck Champlin, Managing Editor

Yiorgos Naoum, Photographer

Tom Milkie, Technical Editor

IHPVA OFFICERS

Dr. Paul MacCready, Int'l PresidentChuck Champlin, President

Richard L. Hargrave, Executive Vice PresidentRob Cotter, Vice President, LandPeter Boor, Vice President, WaterLynn Tobias, Vice President, Air

Stuart Huston, Executive SecretaryTheresa Doran, Treasurer

Lynn Tobias, Membership Chairman

BOARD OF DIRECTORSEddy Merckx, Honorary Chairman of

the Board, BelgiumAllan Abbott, M.D., USA

Jose Domingo Arregui, SpainFred DeLong, USA

Wolfgang Gronen, GermanyChester Kyle, Ph.D., USA

Jack Lambie, USARene Jacobs, BelgiumRobert Jones, USA

Charley Tantet, FranceSinichi Toriyama, M.D., Japan

Otto Weinmann, Jr., SwitzerlandFrank Whitt, England

David Gordon Wilson, PH.D., USAJorgen Beyerholm, Jr., Denmark

John Stegmann, Republic of So. AfricaPeter Selby, England

Copyright © 1982 by the Int'l HumanPowered Vehicle Assoc., Inc., a non-profitorganization, P.O. Box 2068, Seal Beach,California 90740 USA. U.S. subscription/membership $15.00 per year. Canada/Mexico$17.00 per year. All others $20.00 per year.Bulk rate postage paid at Huntington Beach,CA. The opinions expressed by authors donot necessarily reflect IHPVA policy.Until further notice, please address all cor-respondence relating to this publication c/oChuck Champlin, 2614 Halm Ave., Los An-geles, CA 90034 USA. Communications tospecific staff or officers will be forwarded.

A WORD FROMTHE PRESIDENT

It is with great pride (and relief) that wepresent another edition of Human Powermagazine. We hope you enjoy it.

The momentum of the IHPVA has neverbeen greater than it is now, and I'm truly proudand excited to be part of the HPV revolution.

This year is packed with important events.Already we've held a race in Carson, California:the Carson Human Powered Speed Challenge(article on Page 9) where the Easy Racer missedbreaking the 4000 meter individual pursuitrecord set by the Vector last October by barelya tenth of a second.

The American Society of MechanicalEngineers (ASME) entered the HPV world ina big way with a race held May 21 and 22 inDavis California. The June HPV News willcontain a full report.

Our Hydro Challenge is finally going tohappen this year. Allan Abbott is organizingthe second HPV Scientific Symposium forOctober 22 in Long Beach. And, the SpeedChampionships are moving to Indianapolisthis year, finding a good home at last withenthusiastic and highly qualified organizers.

Here at IHPVA headquarters, the officersand I have been working in close cooperationon a four-part campaign to strengthen andexpand the association.

1. Increasing awareness about the organiza-tion, and increasing membership.There is an ever growing interest in the HPV

movement and opportunities for expansion ofthe IHPVA are fantastic. Tell your friendsabout us. If you are interviewed on TV or inthe press, try to mention our name and thecity: Los Angeles or Seal Beach. We finallyhave a number in the phone book. It's 213-204- 2424.

Increasing membership is the best way for usto offer races and other activities for members.Any way you can spread the word will beappreciated.

2. Holding more races and other events.The reason we exist, after all, is to allow

vehicle builders to show and race their creationsin a controlled setting with timing and safetyassistance.

3. Moving boldly into water-vehiclechampionships.Vice President for water, Peter Boor, is

organizing the first Hydro Championships, tobe held at Marine Stadium in Long Beach,California Sept. 4. We feel this is a major stepfor the IHPVA, to broaden its appeal. So getto work on those vehicles (and see Peter Boor'smessage about the race in this issue).

4. Firming up production of IHPVApublications.

We have committed to sending you an HPVNews or Human Power every month, to keepyou up on events and design ideas. Of coursewe welcome any and all information andarticles.

Finally, I'd like to second the thoughtsexpressed by Lynn Tobias last spring. TheIHPVA is truly a human-powered organization,with annual energy expenditures running intothe thousands of Humes. (A hume is theenergy spent on a volunteer basis by oneperson in one hour.)

The volunteers at headquarters love theirwork with the association, but it often cuts intotheir real work time and time with their families,sparking problems in both areas.

May I urge you to make the headaches worthit. Stay in touch with letters or calls. Let us

3

know what you would like to see happeningand where the association should go. But mostof all, think of ways you might help.

Anything you do will be greatly appreciated.Personally, I would like to hear from any-

one who has a thought, a gripe or a due bill(just kidding on that one). Feel free to writeme at 2614 Halm Ave., Los Angeles CA 90034.I'd like to help make your organization more ofwhat you had in mind.

Chuck ChamplinPresident, IHPVA

GOODBYE, MR. PRES.,HELLO, VP-AIR

The past year has seen the beginnings ofmany new areas of growth for the IHPVA. Notonly has the membership doubled (about975 members now), but the number of mem-bers who are actively participating in thefunctions of the Association has increaseddramatically. This includes members forminglocal chapters in their areas, working to developnew race locations such as Indianapolis, andthose in Southern California who are involvedin the administration and publications of theIHPVA. With this help we can provide moreand better competitions and keep you betterinformed with more frequent issues of 'HUMANPOWER' and more up to date through the'IHPVA NEWSLETTER'. But there are someother 'mores' that the IHPVA needs; they aremore input, more feedback and more involve-ment from YOU, the members who ARE theIHPVA. Without the efforts of a great many ofits members, a volunteer organization such asours will never reach its full potential.

Here are some areas that need the mosthelp: more local chapters; more races and theestablishment of better sites for record attempts;more articles of all sorts for publication in'HUMAN POWER', especially technical articleson design and construction of vehicles; seekingand acquiring financial support and sponsorsfor the IHPVA and for races; and the develop-ment of better member services such as sourcesof information or materials, donation ordiscounts on components, or finding out whoin your area is doing what.

AND NOW A WORD FROMTHE NEW V.P. - AIR

You haven't seen much about humanpowered air vehicle activities in the past and Ican't guarantee that this situation will beradically altered. Nevertheless, I would like tohear from anyone and everyone who knows ofany human powered air vehicle activitiesanywhere!! I know Paul MacCready has spokenof a competition for aircraft powered byanimals (other than humanoids) in whichflying animals would be restricted from em-ploying their normal mode of flight. Thereare also awards offered for human poweredflight in England and for helicopter flight. Ifyou know of others or have details on thesecompetitions, drop me a line.

I would like to see more activity stimulatedby the IHPVA. Some practical possibilitiesinclude; a design competition (on paper whichwould hopefully lead to construction); scale-model competition; human propelled lighter-than-air vehicle competition; or perhaps aground-effects competition. Again, if you haveany comments, please write.

Lynn John Tobias,6372 Alexandria Dr.,Huntington Beach, CA92647

HUMAN POWER Spring 1983

-~I- -� -~14--^1���1-1��' _11_---(--·-·-···------ �--11_1__-�---- .-- --~ L- -

Figure 1. Human Powered Vehicle Speed Records

20t1I

60

50

40

30

Reord Vehiclsirlirs, Barczew skl 6992' 101 3 KPH

t Strtemo ined roSttndC~e cle3 O te eIVolghti9. Vector MPH2 t e o Peoce 0El- e3 Streaminel Hand and Foot Power d

uJdre cel e 7 deC C

4 Slr'eamlned Supmie cceeI 94 7i i KPH Vo4

5 StrpamlIned Stndard Trlllt Bivcr/l 58 89 ]GrylsJ (VoPghtl4

6 Seeamined Standard Tandem Bilctl MPH Vector

it Slreame lre SleinC Tandeem Teecyelt IGrr. AnO ed Ntzi 57 07 7 /

8 Streamhined Prone Tlplet Han and CtVoleght). vectoree 5666 IGtiiI tVolght4Foot Powered TrlcyCI

e vectorg StrtamC tned Sueicne Brck to Bac[ kI ttt] Sd43

TENUieCr T IRssel Stton]ee 54 .e.3 10 Streamtined Suptne Btcycir White Lqhrninq

·a~enP. :~ldAsl(D~lnsr) I ~ rh Halon: Ilyle96

4993~

PStepl.r% LVCesue, O rl 48 95 -4 9 38 Tetrrtol IVanVdle kenburCh-

ILeeVetiluel 47 80 lOAbbott IAbbo t 2

200 METER FLYING START ._MULTIPLE RIDER RECORDS

INorton -Deetoni 44 87(Norton)f _ 44 69 !Skailn; iKyre)

1

I 42 ? !Skaene tyre)'432 IS4.,Kel

1

/ tMasloe iStandard 1yel

2OOOMETER FLYING STARTSINGLE RIDER RECORDS

36 94t tEdtardsl (Vol§hti4

Vector

til '10) 131 06 31 40 HOUR REcoRDS

1rlhetl IFaure] /

.,. I I I I I I I l I I I I

1930 1940 1960 V 1970 71 72 3 74 75 76 77 78 79 1980 81 82

YEAR vP re e t

Records as of 11/8t

OLYMPIC BIKESFrom Page 1

bicycle racing speeds can be dramaticallyimproved by lowering the wind resistance of aracing bicycle, and the rider. About 2/3 of theair resistance is due to the rider and 1/3 due tothe bicycle. 1 The aerodynamics of the rider canbe improved by design of helmet, clothing, andshoes and by choice of rider position. Some ofthe common ways of improving the aero-dynamics of the bicycle itself are by streamlin-ing, smoothing components, decreasing surfaceroughness, lowering frontal area, and by properlocation of the components. Wind resistanceagainst the cyclist may also be lowered byexternal factors such as tail winds, cross winds,drafting, auto traffic or even by holding races athigher altitudes. A brief discussion of each ofthe above factors follows.

Equipment Modification

1. Streamlining

Figure 1 shows that the world humanpowered vehicle speed records increased rapidlywhen completely streamlined pedal cyclesbegan to be used for record attempts. Stream-lined vehicles are much faster than standardbicycles. The present 200 meter flying startrecord for a standard bicycle is 68.05 KPH(10.58 sec), and was set by Gordon Singletonof Canada in 1980. The record for a stream-lined vehicle is over 25 KPH faster; 94.77 KPH(7.597 sec), set by Dave Grylls of the USAusing a streamlined supine tricycle. The move-ment toward completely streamlined humanpowered vehicles accelerated rapidly after1975 when the International Human PoweredVehicle Association was organized. Table Ishows the comparative power required bysome of the human powered vehicles that havebeen developed since 1975. At 32 KPH, thenewer machines require less than 30% of thepower used by a standard bicycle at the samespeed. Obviously from the above, streamliningcan dramatically improve both the speed andthe efficiency of a bicycle.

However, such exotic streamlining is illegalin standard bicycle racing, although somestreamlined components and frames have beenpermitted. Since the elaborate streamliningused by the vehicles in the International HumanPowered Speed Championships cannot be usedin standard cycle racing, it will not be discussedfurther. Only modifications that are legalwithin the Union Cycliste Internationale ruleswill be covered.

HUMAN POWER Spring 1983

Table 3 - Aerodynamic Drag of Bicycle Equipment

Bicycle Components -Speed 32 KPH4,5

Drag IncreaseGrams

B cycle Bare 0

Blcycle lus Water Bottle +40

Bicycle plus Ferders +130

Bicycle plus Panl e and Pack +270Bicycle with covered FrBicycl with covered Fame -90and Wheels

Aero Drag of Helmets at 48 KPH

Bare Malkirl ,t!h wig har)

Mankn pius Clnell, Strap Helmet

Maikin plu BldOncie Hemlet

-60

-120

Best Czech Aro Helmet

Worst Head wth Hdlr

I2

I

a

Figure 3. Effect of Wnds5

K ILOMETERS PER HOUR

T

K

R0Ie0II

I

SPEED-MILES PER HOUR

Figure 4. Estimated Effect of Passing Traffic6

I0I

If the aerodynamics of the bicycle and riderare to be improved as much as possible, theneach equipment item should have an efficientgeometric form such as the typical wing shapedoval. As it is, even on the best racing bicycleshave components that could be improvedgreatly. The question is whether such equipmentis important in racing? Table 2 shows how muchthe times would improve in the 4000 meterpursuit race with aero drag reductions offrom 10 to 300 grams. Even 10 grams lessdrag would give a 0.2 second advantage; so

10

+1 +2 +3 +4 +5 +6

INCREASE IN BICYCLE SPEED KPH

Figure 5. The Effect of Altitude Upon Air Density and Bicycle Speed6

1.2THEORY

1. I 1 HOUR RECORD V/V oHAMILTON~>U~~~~~ i8 -1000M RECORD-51RCU

1 HOUR RECORD-MERCKX0 9 MEXICO CITY

0.8

c 0.6 I I

0 500 1000 1500 2000 2500 3000 3500

ALTITUDE-METERS ABOVE SEA LEVEL

MEXICO CITY = 2260M 1-20% DENSITY)BICYCLE SPEEDS ARE +3-5% GREATER

obviously aerodynamic equipment would beuseful if significant drag reductions could beachieved and if the equipment could be madeto function properly. Table 3 and Figure 2show the aero drag of typical items of bicycleequipment such as wheels and helmets. Themeasurements were made in a wind tunnel orby coast down tests. As can be seen, ratherlarge aero drag decreases are quite easy toachieve.

However, sometimes aero components weighslightly more than standard. Another questionis whether the added weight might cancel anyadvantages? Table 4 shows the effect of addingmass to a bicycle in the 4000 meter pursuit race.As much as 800 grams may be added if aslittle as a 10 gram reduction in aero drag can

Table 2 - Improvement in Bicycle Speed by AerodynamicDrag Reduction. 400 Meter Pursuit, 50 KPH

Drag Lecreae Tlrne Decrease

Grams Seconds

0 -0.0

10 -0.2

30 -0.8

50 -1.5100 -2.7

200 5.5

300 -8.5

D 3 11 + 0 176 V2where V m and newtonr

Table 4 - The Effect upon Acceleration Time of AddingMass to a Bicycle. 4000 Meter Pursuit, 50 KPH.

Added Mass Added TlneGrsanls Seconds

0 0.0

50 + 0.01

100 +0.02200 +0.04400 +0.08

600 +0.11800 +0.15

Assume 15 seconds to accelerate to 50 KPH

m2 m = 80 Kg (the mass of cyclet2 T1 plus rider)

t1-15 econd

Figure 2. Aero Drag of Bicycle Wheels

I

,.iT8a LC.H Kvle

5

I

4000

be achieved. At least in this comparison, thepositive benefits of aerodynamics far outweighthe negative effects of adding mass.

There has been some speculation that aeroequipment would be worse in cross windsbecause of higher drag and instability. Thiswould depend upon the wind velocity anddirection and the equipment. Aero tubing forexample can actually have a lower drag in across wind because of aerodynamic lift (itacts like a sail). Of course stability, componentstiffness and other factors must also be con-sidered before using aero equipment in a parti-cular race. Road races and sprints are obviouslyquite different than time trials, and thereforequite different equipment should evolve foreach.

2. Smoothing of Components, DecreasingSurface RoughnessPoor aerodynamic shapes such as bolts,

clamps, levers, cables, posts, etc. can all beimproved or eliminated by proper bicycle design.The object of smoothing components is toavoid sharp edges, corners, rapid changes incontour, or other shapes that might causeturbulence or unnecessary air resistance. Roughsurfaces can also cause excess air friction.

One interesting factor to consider in smooth-ing components is the speed that the bicyclewill travel. All types of bluff or streamlinedshapes such as wings, cylinders, ovals, cubesor spheres go through an aerodynamic transi-tion when the wake changes from laminar toturbulent flow and the drag forces decrease.Streamlined shapes go through a gradualtransition but objects such as cylinders abruptlychange as the critical speed is exceeded. Thistransition was noted frequently during windtunnel tests of both helmets and bicycle wheels.At racing speeds, bicycles have many compo-nents that operate around the critical transitionpoint. In this case it may be more advantageousto have rough surfaces than smooth (like thedimples on a golf ball), in order to prematurelytrip the flow and cause turbulence in the wake.Careful wind tunnel work is required to identifythose components that can be improved byutilizing supercritical flow.

3. Proper Location of Components.Given a choice, aerodynamically poor

components should be located in the windshadow or wake of other equipment so thatthe combined drag will be less. For minimumdrag it is more important to have a cleanstreamlined front face than to improve therear profile. Items such as brakes, cables, rods,etc. should be either hidden in the frame orplaced behind other more efficient shapes. Astreamlined water bottle cage can be designedfor example that presents a smooth profile tothe wind when combined with the bottle.

4. Decreasing Frontal AreaSince pressure drag normally predominates

over friction drag for bicycle components,minimum frontal area is important. Componentsthat can be redesigned or oriented differentlyto give less frontal area will have a lower airdrag. A good example is the bicycle rider usingthe uncomfortable egg shaped body position.This posture minimizes frontal area and also ismore streamlined, giving much less resistancethan a more upright position. When ridersare in crouched racing position, with elbowsbent and hands on the lower handle bars, theyhave at least 20% less wind resistance thanwhen in touring position with hands on theupper bars and elbows straight.

Other Methods of Decreasing Wind Resistance

1. DraftingIn a pace line, closely drafting riders are in

an artificial tail wind that decreases the air dragof those in the rear by over 40%. Power requiredis about 30% less for all except the leader whouses about the same amount of energy as a solorider at the same speed. Table 5 shows the

Machine Frontal Drag Percent rq a Required Speed Wilth MaxmumArea m

2Coeficient Reducion Power at No Power Compotitron

(Area in2) Cd at 32 KPH 32 KPH-Watts Inrease-KPH Sp ed-KPH

(IncreaaMP Spd-MPH SpedMPH')

Rare Bicycle .0 7 7 203 32.0 .78 O 2 03 32 --I '9(10.6) (19.0)

1 Bcylde ~I .50 .60 13% 177 33.5 54.72C Front Fairin 1 1196 (20.8) (33.9)

Bicye + .55 52 22% 159 34.7

o F airing 1II (21.6) I (21.5)

Palumho Supin Triyde .35 .77 26% 151 34.5 58.21ae I(13.7) 21.4 (36.1)

Van Valkenburgh Aeroshell 6 .05 .32 34% 125 36.8 54.2V.. V.1k,.b."t, A. h.11 (.65 .32 34% 126 36.8 54.22

(Coars Upper Body) (25.5) (22.80 (33.6)

A eroshell + Bonom Skin .68 21 48% 97 39.8 74.05I26.7 . (24.7) 464)

~~~~~I-Pdomo Tricycle 46 .28 55% 92 40.9 71.42wthFaiig (18,1) (25.3) (44.3)

Kyle F.ull Fair.9in 1 .10 67% 68 4 74.77

(27.9) ( 28.5) (46.4)

,Van Valkeburgh Prone .46 .14 68% 64 46.4 79.47

Q. udrecylewth Faiing (18.1) (24.1) (40.3)

Measured t the International Human Pared Speed Championships Fnom: "Predictn1Proceeding

Table 5 - The Effect of Drafting3

Decrease IWheel Gap Meters Wimd Dra

0.2 44%0.4 -42%

0.6 -38%

1.0 * 34%1.5 30%

2.0 -27%

decrease in wind resistance with the wheelspacing between bicycles. Naturally the closerthey draft, the greater the benefit.

2. Tail Winds and Head Winds

Figure 3 shows the effect of tail winds andhead winds upon bicycle speed. If it is assumedthat a rider can produce the same steady statepower no matter what the wind speed, then thecurve may be used to predict bicycle speedwith either leading or following winds. As arule, a bicycle is affected about half the windspeed. That is, a 10 KPH head wind will slowthe bicycle about 5 KPH while a 10 KPH tailwind will speed the bicycle up about 5 KPH.Cross winds can either increase or decreasespeed depending upon the design of the bicyclecomponents. Large front fairings have beentested in a wind tunnel and at yaw angles upto about 20° their drag was actually lower,showing that they extracted energy from thewind much like a sail.

3. Passing Automotive TrafficTime trial speeds are often influenced by

passing automotive traffic in open courses.Figure 4 shows the approximate effect ofpassing traffic upon time trial speed withvehicles from small autos to large trucks. Thecurve was made by observing a very consistenttime trialist on a level public highway, and byusing a very accurate speedometer. Speedincreases from 1-5 KPH were measured whenvehicles passed with about 1.5 meters sideclearance. If strong cross winds existed, thenalmost no effect was measured. When passingtraffic slowed, approaching the speed of thecyclist, then the duration of the effect increaseduntil sometimes it became permanent (thecyclist was drafting at the side of the motorvehicle). Naturally when motor vehicle trafficwas heavy then the speed increase was greater.If a steady stream of traffic was going by thenthe speed increased as much as 5 to 10 KPHcontinuously.

4. The Effect of Altitude upon Bicycle SpeedAs elevation increases, air density decreases,

as does the wind resistance. If bicycle speed11

s International Cnenre on Human Powered Trnsportation, Sn Deg.o, 1979. Chester R. Kyle.

depended only upon air resistance then veloci-ties would be much greater at higher elevations.However, less oxygen is available and thusaerobic endurance is less, so the effect is lowerthan might be predicted by theory. Figure 5shows the variation of air density with altitudeand the theoretical increase in bicycle speedwith altitude. Some actual race results areplotted, these are less than theory in all cases.The world 1000 meter record, and hour recordwere set in Mexico City, elevation 2260 meters,where the air density is 20% lower than atsea level. Surprisingly however, the records forthe 200 meter sprint and for the 4000 meterindividual and team pursuit were set at nearsea level. In general bicycle speeds at Mexicoseem to be from 3 to 5% greater than at sealevel. It would be interesting to hold a worldtrack championship at La Paz Bolivia, elevation3960 meters, where air density is 33% lowerthan at sea level. If Top athletes were present,world records would surely be inevitable.

References

1. Nonweiler T., "Power Output of RacingCyclists", Engineering, May 10, 1957,p. 586. Nonweiler T., "The Air Resistanceof Racing Cyclists" Report No. 106, TheCollege of Aeronautics, Cranfield, EnglandOct., 1956.

2. Kyle, C.R. et al, "Predicting Human PoweredVehicle Performance Using Ergometry andAerodynamic Drag Measurements", Pro-ceedings, International Conference onHuman Powered Transportation, San Diego,Ca. 1979.

3. Kyle, C.R., "Reduction of Wind Resistanceand Power Output of Racing Cyclists andRunners Traveling in Groups", Ergonomics1979 v. 22 No. 4 p. 387-397.

4. Kyle, C.R., "How Accessories AffectBicycle Speed, (Is Your Water BottleSlowing you Down). Bicycling MagazineMarch 1976.

5. Kyle, C.R., "Factors Affecting the Speedof a Bicycle". Engineering Report No. 73-1,Nov. 2, 1973, California State University,Long Beach.

6. Kyle, C.R., "The Aerodynamics of Bicycles",Bicycling Magazine, May 1982; The AIAAStudent Journal Spring 1981.

HUMAN POWER Spring 1983

Drag and Speed Characteristics of Streamlined Human Powered Vehicles

r .UPr .....i ...... werd Vehicle Perfo.....e Uslin re merM and ~fDoe namlc ura Meawrememls

----

FLOATFrom Page 13

We weighed the float two weeks before theparade, and found to our dissapointment thatthe weight was already 5000 lbs. There wasstill another 800 lbs of wood and steel to add,as well as at least 1200 lbs. of flowers, glue,paint, etc. There was nothing that could bedone about it at this point, so we just hopedthere wouldn't be a headwind down ColoradoBlvd. on New Year's day.

New Year's eve was spent inching throughthe streets of Pasadena in a convoy of overtwenty floats to the parade staging area onOrange Grove Blvd. The float felt more sluggishthan it had during tiral runs, and the flowersand glue were causing minor problems withthe mechanisms that actuated the five fans oneach side. Paul MacCready was driving,practicing the steering and braking he wouldbe doing during the parade, and I was practicingmy job of operating the clutch and gearshiftlevers. The steering position was on a platformten feet off the ground at the front of thefloat, and the gearshift was in the fifth row seat.To communicate, Paul and I had two-way voiceactuated headset radios, which seemed to workvery well.

The other float pedalers for the paradewere Chester and Joyce Kyle, Bryan Allen,Joan Lind (an olympic silver medalist rower),Ron and Sue Skarin, Allan and Colony Abbott,Izzy Lewis, and Jack and Karen Lambie.Everyone arrived at Steve Serrurier's house at5:30 a.m. on new year's day for breakfast andto try to fit into the shorts and t-shirt outfitsprovided for us. After packing the float's trunk(yes, it even had a trunk!) with everyone'sclothes, camera bags, sleeping bags, wheelchocks, etc., we were ready to go. As soon asthe parade started, I realized that the two-wayradio was going to be almost useless - the noisefrom the marching band behind us and thecrowds beside us was deafening! I couldn't hearanything over the radio. I could see Paul wavingto the riders to speed up as the gap between usand the band in front widened. Yelling as loud

as I could, I got the attention of Allen Abbottsitting in front of me. I told him to go to100 percent power and to pass it on. We finallycaught up as we neared the main reviewingstands and television cameras.

Everything went smoothly for the next mileuntil we got to the short steep hill. The planwas to go up at about 2 m.p.h. in second gear.As we started up, it immediately becameapparent that we weren't going to make it insecond, so we stopped and shifted into first,and got underway again at less than 1 m.p.h.The crowd really loved the challenge, andcheered us on. After cresting the hill, I shiftedthrough the gears, going up to fourth, and weall took it easy coasting down the 3 mile downgrade ahead of us.

The easy going didn't last long. While inchingalong slowly waiting for a delay in the parade,the left rear tire suddenly exploded violently,sending up a shower of dried yellow flowerpetals. We stopped dead in our tracks, andparade officials ran over to inspect the damage.They found that the wheel rim had broken, andthey immediately called for a tow truck to pullus off the parade route. Luckily the tow barthat we were carrying was stuck inside thecentral frame, so we were spared the embarrass-ment of being towed. Instead we started upagain under human power, rolling on what wasleft of the rim and tire. The ride was extremelyrough, and the balloons were wobbling pre-cariously over our head. After three blocks, wewere able to turn left onto a side street.

Minutes later Steve Serrurier and RalphHudson arrived with tools and a spare wheel.In another ten minutes, the new wheel wasmounted, and we backed down the side streetback onto Colorado Blvd., and took off againin the parade.

Things went well enough until we started upthe final hill near the end of the parade. Evenwith all of us putting out maximum power, westeadily fell behind the float in front of us.Then it happened. The left front tire exploded,

just as before. This time we knew what to do -we just kept on pedaling and again turned offon a side street. We were close to the end ofthe route, and there wasn't much time foranother wheel change, so we just walked therest of the way.

I haven't determined yet why the wheelsfailed, but I later found out that the tire pressurehad been increased from 40 psi to 60 psi theday before. Maybe this increase, along withheating from the sun, pushed the pressureabove what the wheels could safely handle.

Finally, it is interesting to compare theHonda float to the Arco hand-carried float.The Arco float weighed 1200 lbs. and wascarried by 40 people, so each person was ineffect propelling 30 lbs. of float. The Hondafloat weighed about 7000 lbs. and was propelledby only 12 people, or each person was propel-ling almost 600 lbs of float - 20 times morethan Arco!

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BICYCLES AND TRICYCLES, by Archibald Sharp. Definitive in 1896 and still right on.Dynamics, structures, gearing, etc.

Softbound, 536 pages, $8.95

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Hardbound, $17.95

SYMPOSIUM TRANSCRIPTS, proceedings of the first Scientific Symposium held Novem-ber, 1981 in Anaheim. A unique storehouse of information on air, land and watervehicles.

Nearly 200 pages, softbound, $20.00

T-SHIRTS, souvenirs from the 7th and 8th IHPSC. (Specify quantity, color-yellow or ecru-and size, S,M,L,XL.)

MEMBERSHIPSCircle: New member Renewal Address change (include label).Annual dues are $15 U.S.; $17 Canada/Mexico; $20 Elsewhere

All prices include postage and handling. Please allow6 to 8 weeks for delivery. Foreign orders add $1 perbook for surface mail; $7 per book for airmail, $3 perT-shirt air mall Please make checks payable to IHPVA.(U.S. checks or International money orders only, please.)

Send toIHPVA (Dept. HP)PO Box 2068Seal Beach, CA 90740

Total

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15 HUMAN POWER Spring 1983

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Increased (o.mt,,r. Set? dnd ttltlently

TOUR EASY Ready ,, ride sith ZZIPPI-R falrln

FRAME SET Wih irk. har,. tlnl wheel & -1dl

EASY RACER. (uhlm elt

EASY PLANS Bulid vlur ,own Irlo , ,ld hlke, 525

COMPLETE INFORMATION AND ORDER FORMS S1(Clhf-rla reldcnlx add h' Iai

*HPVA PRACTCAl ,LHI( I WINNF R Iq2*IHP\'A SrRAML[NFI) R()A) RA(C WINNt R I178 & 182 '"IHP\A SP I:D I(HAM HI('Y(P'I % 1979 & 108(I*WNN R SIX SIRAlLHI I} AM TRIATHAl ONS I9I

RECUMBENT 3 WHEELCYCLECARS

KITS$695.00* DOES NOT INCLUDE

BICYCLE PARTS

* Kit can be built as 3, 5. 10 or 15 speed* Assembled chrome moly spaceframe* Adjustable ventilated recumbent seat* Complete steering system* Front drum brake hubs* Fairing mounts* Fittings and instructions

aerocoupecyclecars

537 SOUTH RAYMOND AVE., PASADENA CA

(213) 681-1116 91105

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HUMAN POWER Spring 198315