Build the Economy Champ:3-WHEEL SUBURBANRUNABOUT

Fig. 1. The photo o! the Incomplete Run-about above shows Its Inner structure.It'll go 30 mph getting 90 miles/gallon.

• This small, easily-built runaboutlooked good when it was first intro-duced in SCIENCE & MECHANICS backin 1961, when gasoline sold for abouttwo bits a gallon. Today, with the costof the fuel about $1.30 a gallon and noend in sight to its spiralling price, thecar represents an idea whose time hascome.

Fuel economy? With its 3.5 - HPClinton engine, the runabout will reacha respectable 30 miles per hour, andat this speed use less than 1.5 quartsof gas for each hour run, which repre-sents about 90 miles to the gallon.This is a one-person vehicle you canuse for trips to the commuter trainstation, or your wife can use it for hershopping trips. You sit in a comfortablypadded seat that is suspended on 44shock-absorbing rubbers that isolateyou from road bumps and vibration.Steering is controlled by a lever, andstart and speed is controlled by amotorcycle handle bar throttle grip on

the steering lever. Brake is controlledby a motorcycle hand brake lever. Noneof the driving controls are operated bythe feet. If it takes you longer thanthree minutes to leam how to drive it,it's because you are so enthusiastic toget going you haven't had time to payattention to what's happening.

Even with all parts purchased new,this runabout should cost less than$700, including the weatherproof cab.Check the license requirements in yourarea before driving on public streets;some states require lights, hom, fen-ders and the like.

The basis of the car is the Clintonengine, a ball-bearing, horizontal shaftmodel that is an improvement on theone used in the 1961 car. It developsits 3.5 rated horsepower at 3,600 RPM.A centrifugal clutch connects the en-gine to the single drive wheel via ajack shaft, with chain drive. All theparts you need for the drive system,includ'ng the wheels, can be obtainedthrough major automotive supply

houses, small engine shops, motorcycleshops, and hardware stores that caterto industrial and fanning needs. Thebest bet is to show your supplier theseplans so that he can provide.you withthe correct components. Note that youmay have to change bolt hole locationsfor mounting some of the componentssuch as the pillow block assembly.

The steel material needed can bepurchased from a steel supplier likeRyerson, which has outlets locatedthroughout the country. Cost of thematerial itself, based on per-foot andper-pound prices, should be less than$60. See if the supplier has randompieces in stock that are somewhatlonger than what you need; this willbe cheaper than paying $20 for eachpiece that must be cut from standardstock. You could wind up paying asmuch as about $160 in cutting charges.

Frame Construction. Cut the frontaxle to length as in Fig. 4. Mark the10* end cuts with a protractor or bevelsquare and use a new blade in yourhacksaw so the cut will not run off toeither side. This is important becauseaccuracy of the 10* king-pin inclinationof the steering assembly depends uponthese cuts. After cutting, check with asquare and file ends, if needed, tomake them square with the axle sidesand at 10* with top or bottom sur-faces of the axle.

Cut the two frame rails (Fig. 4) to

size in the same manner. The 6* anglecuts on the ends control the casterangle of the steering assembly. Whendrilling the 5/8 -in. holes through framerails for the rear axle' align ends of therails and damp one on top of the otherso you can drill both holes at the sametime. You will then be certain that therear axle will parallel the front axlewhen assembled. If you use a home;workshop size drill press to bore theholes, start with a small drill (about1/4-in.) and gradually work up to the5/8-in. size. (5/8-in. drills with 1/2-in.shanks are available.)

Unless you have your own arc-weld-ing equipment, you are probably goingto have your runabout frame welded ata local weld shop. It would be a goodidea to cut and fit all frame partsneeded to have welding done at onetime. It will be cheaper this way.

Going back to the front axle, youwill next make the spindle yokes (Fig.4). Shape these from 1/4 x 1-1/4-in. steelbar stock by heating and bending it

around a forming block and then drill-ing the 3/4-in. spindle holes. A 3-in.length of scrap steel about 1 in. squarewith 1/4-in. radius round corners groundon each end could be used for a form-ing block. However, since this is quitea job in any home workshop, we havelocated a source of supply where theyokes may be purchased, bent anddrilled. In either case, weld the yokesto the ends of the axle as in Fig. 4A.

Now place the 6* cut ends of theframe rails against the back side of theaxle and square with it as in Figs. 2and 6. Weld the rails to the axle. Awooden block cut exacdy 8-in. long andclamped between the rails will holdthem in position. Be sure the rails are4 in. on each side of the axle centerand that the bottom of the axle tilts 6*forward as in Fig. 6. Locate and clampthe seat support to the frame rails andweld in place. This completes the basicframe.

Engine and Jack Assembly. Thisassembly is located directly above therear drive wheel and in back of theseat as m Fig. 2 and 6. First cut therequired number of each of the foursupport parts as detailed in Fig. 4.Then locate and mark position of thefour support uprights, on the framerails. Measure these from the center ofthe 5/8-in. rear axle holes in the rails asin Fig. 2C, Assemble the support partswith small clamps, position assemblyon the rails and tack-weld in place. Re-move clamps as you tack-weld. Afterchecking location and squareness, com-plete the welding.

Location of 11/32-in. drilled holes inthe engine and jack shaft assembly(Fig. 2B) is correct for the engine andpillow-block bearings called for in thematerials list If you should use anyother engine or bearings, relocate theseholes as necessary.,

Rear Wheel and Drive. The specified :rear wheel comes complete with 60-tooth sprocket and brake assembly.Only additional parts needed are the irear axle and two axle spacers to posi-tion and hold the center of the rearwheel tire midway between the rails(Fig. 3).

Make the axle from 5/8-in. steel shaft-

Fig. 3, left. Drive wheel. Note: 18-tooth sprocket between bearings.

ing and have 5/8-in.-18 threads cut oneach end as in Fig. 4. Make spacersham 5/8-in. I.D. x 3/4-in. O.D. steeltubing as in Fig. 4. Cut slightly over-size so you can file and fit them to pre-vent side-to-side wheel movementSince these spacers bear against innerrace of the wheel bearings, do not fittoo snugly. A small amount of take-upcan be achieved by tightening the axlenuts. When the wheel spins freely,without end play, drill rear axle endsfor cotter pins to lock the slotted nutsin place. Weld hub of brake shoe toframe rail.

Now, bolt pillow-block bearings inplace on the support. Install the 3/4-in.jack shaft and the 12- and 18-toothsprockets as in Fig. 3. Note that the18-tooth sprocket goes between thebearings. Bolt engine in place and in-

stall the centrifugal clutch on the en-gine shaft

With 12-in. metal scale, or otherstraightedge, held flat against the sideof the 60-tooth sprocket, align the 12-tooth sprocket on the jack shaft withit. Lock jack shaft in place with set-screws on the pillow-block bearings.Also lock 12-tooth sprocket to the shaft.Similarly, one up and lock engineclutch sprocket with 18-tooth sprocketon jack shaft. Now, with a scratch-awlor 3-comered file, mark sprocket andbearing locations on the jack shaft soparts can be reassembled exactly asthey now are. Then remove the pillow-block bolts and take the jack shaft as-sembly off the support

Of two ways to fasten sprockets tothe jack shaft, the best is to cut 3/32x 3/16-in. keyways in the shaft and key

Fig. 5. The Runabout makes a great week-end fun vehicle or an economical commutercar. Added cab protects from weather.

the sprockets in place. Since this re-quires you to have a local machine shopcut the keyways (unless you have alathe with milling attachment), youmay choose simply to weld the sprock-

3-WHEEL SUBURBAN RUNABOUT

ets to the jack shaft as we did. A dis-advantage in doing this is that you locka pillow-block bearing between thesprockets. If at some later date you wishto replace one of the sprockets orchange the speed ratio, it would bedifficult to remove unless you put theshaft in a lathe and turned off thewelds. Do not try to lock sprockets tothe shaft with set-screws alone—the loadon the sprocket is far too great.

When you have the sprockets se-curely fastened to the jack shaft, reas-semble it and again bolt the bearingsto the support. Install the #35 chainwith connector links as on a bicycle.First adjust chain tension from rearwheel to jack shaft by placing washersunder the engine. Chains will stretchslightly after you have used your run-about, and a few washers may have tobe added to take up the slack.

Front Wheel Spindles. Grind a 10*angle flat on the heads of two 5/8 x 4-in.hex-head bolts as in Fig. 4, and weldto the spindle tubes. Make the tie-rodarms, and also weld them to the spindletubes. Note that arms are placed 60*from the 5/8-in. spindles. Make sure the5/8-in. king pins will go through thetubes. You may have to run a 5/8-in.drill through to clean up the tubes ifdistorted by welding. Drill the 3/16-in.holes through one side of tubes only.

When assembling spindles to theyokes, first tap the bronze bushingsin the 3/4-in. yoke holes so that theflanges face each other inside the yokes.Saw off and file the projecting 3/4 -in.dia. parts of the bushings flush withtop and bottom of yokes. Then fitspindle tubes between flanges of thebushings and install king pins as in Fig.2A. Note that steering king pin goes on ,left side of the axle. (Left when sittingin the runabout).

Spindle tubes should fit snugly be-tween bushings. You can file tube endswith a fine-cut mill file and polish withabrasive paper for a smooth finish, par- ;ticularly where tubes contact the yokebushings.

With king pins in place, spot drillthem through the 3/16-in. tube holes.Remove king pins and spindles fromaxle yokes and drill the 3/16-in. holesthrough both pins and tube. You cannow permanently assemble spindlesand king pins to the axle yokes anddrive 3/16 x 1-in. Roll-pins through theholes.

Fasten front wheels on the spindleswith slotted nuts and cotter pins asyou did the rear wheel. Make the tierod as in Fig. 4. Install it with the

PLYWOOD SKIN

PROMT POSTSEC.B-B 1x1X46^*

LEFT SIDEROOF FRAMING

MEMBERS-'LOWER BOX

MEMBER"

FRONTCHOSSBWCES

Fig. 8, above, is the 3.5 h.p. Clinton en-gine, its suggested retail is $154.90.Fig. 10, right, shows how to assemblethe basic shell. Follow text carefully.

ball joints to tie-rod levers on thespindles as in Fig. 2A. Adjust the tierod so that the toe-in of the frontwheels is 1/16-in. Measure the toe-infrom the centers of the front wheeltires as in Fig. 2B.

Steering Lever. Cut two pieces of7/8-in. steel tubing as in Fig. 4 andweld together at right angles. Slide themotorcycle throttle and;brake controlson the steering lever as in Fig. 2. Weld

3-WHEEL SUBURBAN RUNABOUT

the lever to projecting end of the steer-ing king pin. Make a sleeve from a 3-in. length of 74-in. tubing as in Fig. 4to act as a spacer between the 5/8-in.steering king pin and the 34-in. I.D.of the 7/8-in. steering lever tube.

Connect cables from brake lever torear wheel brake and from throttlecontrol to carburetor throttle lever.

The Seat. The specially designed seatfor this runabout gives a comfortableride. Since the frame has no spring sus-pension system as in an automobile,suspension is built into the seat. Don't

attempt to install an ordinary paddedseat.

To make the seat, draw full-size pat-terns of the bent tube parts on card-board following the squared pattern inFig. 7. Use an electrician's conduitbender to bend the tubes. Place part

3-WHEEL SUBURBAN RUNABOUT

you are bending over the full-size draw-ing occasionally to check progress. Besure to use a longer length of tubingthan needed for each part as clampson the bender must grip die tube be-yond the bend.

After bends are made, flatten lowerends of the bottom rails and bolt themto the front axle. Braze a 3/8-in. hexnut to lower ends of the side rails. Boltthese to the seat support bar on theframe. Then mark, cut and file, bottomrail ends that join the side rails as inFig. 7. Tack-weld rails together andthen fit and tack-weld the top and bot-torn rails in place. With all seat mem-bers securely tack-welded, remove fromframe and braze the seat tubing joints.Carefully lay out and drill the forty-four 5/32-in. holes as to Fig. 7A.

The seat pad is a sewing machinejob. Unless you're familiar with its oper-ation, you had best let your wife handlethe work—or try yoiir local awningshop. Complete details for making itare shown in Fig. 7B. Although weused blue denim for the pad, you cansubstitute with a plasticized, water-proof material of the type used foroutdoor furniture..

In the meantime, make the 4 hemwires and the seat suspension hooks asin Fig. 7. Make suspension "springs"from 1-1/4-in. wide loops cut from abicycle inner tube. Coat outer side ofeach loop with rubber cement, fold ittwice on itself, then place the cementedloop on a bottle or mailing tube untildry. If you're a 200-pounder, makeloops at least 1-1/2-in. wide. You couldalso make loops from 1/4-in. dia. air-craft shock cord wired as in Fig. 7.

Slide the hem wires into the seatpad hems. Slit hems open at each kinkin the wire, then install hooks and rub-ber "springs" as in Fig. 7C.

Except for gas in the engine, yourrunabout is ready for that trial run.

Building, the Cab. The enclosure forthe bantam three-wheel runabout inFig. 9 has been redesigned and im-proved from the prototype shown in ;Fig. 2 to s'mplify construction by elimi-nating difficult compound bends.

Overall dimensions of this all-weathercab are but 62 in. long and 31 in. wide.Framework cut from 3/4-in. lumber isbuilt up from a 1/2-in. plywood floor,which is bolted to the chassis on sevenrubber mounts. |

Prepare floorboard first, by cuttingit out of a 3 x 5-ft. piece of 1/2-in. ply-wood to dimensions in Fig. 9A.

3-WHEEL SUBURBAN RUNABOUT

Slightly bevel the lower edge to pro-vide a better fit for the plywood skin.Drill the seven holes indicated for thetie-bolts; also the two larger holes forchair legs to pass through. Make therectangular cutouts for the engineblock and footrest. Then shape the twowheel-well inlets, beveling both frontand rear sides.

Cut the footrest panel and bevellongest edge as in Fig. 9B to fit on topof the floorboard. Join with screws andstrengthen joint with two 3-in. metalcorner brackets. Bend brackets open tothe angle as in Fig. 9C and fastenwith 5/8-in. screws.

To install the floorboard, remove en-gine from its chassis mounting bracketsand the seat from the frame. Slip boardover the chassis footrest to lay flat onthe frame. Mark and drill seven 11/32-in.mounting holes dirough the framemembers to correspond widi the 3/8-in.holes in the floorboard.

Now cut 28 washers out of 1/8-in.thick rubber sheet, each shaped 3/8-in.I.D. and about 1 in. O.D. Arrange ingroups of four at each hole betweenfloor and frame. Slip a 3/8 x 2-1/2-in.bolt through each hole to fasten floor tochassis, then tighten nuts until rubberwashers are compressed to 1/4-in. thick-ness. This should reduce the amount ofchassis vibration passed on to thie body.Replace engine.

Building the Basic Shell. Virtuallyframing members are 2 in. wide. Ripstraight pieces from 3/4 x 5-5/8-in. pine.Lay out and cut out the shaped pieceson a band or jigsaw.

Cut the front posts and three frontrails as in Fig. 10. Fasten crosspiecesat center and each end of the posts,using #8 x 2-1/4-in. fh screws andcountersinking heads. Complete frontframe by beveling front of top edge45 deg. as in Fig. 10.

Cut the front and back framingmembers and shaped sides of roof (Fig.10F). Toenail in position, then rein-force roof frame with 3-in. metal comerbrackets shaped to fit inside corners.Fasten brackets with #6 x 1-in. fhscrews. Cut the large diagonal spars asin Fig. 10, shaping ends to fit die angleat floor and roof—72 deg. from the hori-

zontal.Now you can begin framing up from

the floor. When joining parts, first nailtogether to permit adjustments; then asframe takes shape, fasten firmly with#8 x 1-3/4-in. fh screws. Countersinkall screws and use longer ones wherefastening into board ends.

Attach cleats to the floorboard ad-joining side notches as in Fig. 10, lo-cate the large diagonal spars in posi-tion and fasten to cleats. Attach bottomrail of the front frame to edge of footrest panel (B-B in Fig. 10A), thenfasten beveled edge of top rail to roofframe as in left side detail of Fig. 10.

Next make up and mount the wingsupports on each side of the rear wheelas in Fig. 10B. You can cut these toshape from the plywood floorboardcutouts. Glue small members togetherand fasten with screws. From this pointon, check all dimensions at assemblybefore cutting.

Cut a 3/4 x 1 x 17-in. pine cleat toreinforce joint between footrest paneland front frame (B-B in Fig. 10). Layout lower horizontal spars on 3/4 x 5-5/8-in. stock and cut to shape as in Fig.10C. Locate in place to mark notchesfor front crossbrace and large diagonalspar. Cut notches and fasten a hori-zontal spar to each end of the frontpanel-footboard joint and to a diagonalspar at the notch. Shape and installwheel well framing.

Upper horizontal members form thebottom of the side window frames andare notched. Lay out and shape as inFig. 10A, notching to fit over the longdiagonal spars. On right side only, cutthis spar off at front of the diagonalspar and save the front piece for doorconstruction. Fasten remaining portionin place, also the entire left side mem-ber.

Now you can fit and install the twopairs of vertical members for the rearbox as in Fig. 10D. Note that the frontpair "hang" from the upper horizontalmember right in back of the notchedarea for the long diagonal spar andjoin the floorboard. There should bejust enough room in front of these ver-ticals and behind the lower horizontalspars to slide a 14-in. plywood panelin position as in Fig. 10E. Line engineside of the panel with #16-gage sheetmetal as a safety precaution.

Drop verticals from each end of theback member in the roof frame to in-side edges of upper horizontal mem-bers as in Fig. 10. They form the rearwindow. Complete the basic shell byinstalling the two diagonal cross braceswhich support the left side front post.

Installing the Door. Make a simpleframe similar to the door frame as inFig. 11. Note the triangular block inplace of a cross brace below the open-ing. Flair off portions of block or frameas needed to fit the curving plywood.

Trim a 36-in. piano hinge to 34 in.Attach it with #8 x 1-in. fh screws torear edge of door and rear member ofctoor frame so door will swing out as indetail A-A, Fig. 11.

A common night latch will keep diedoor closed tight—and locked when de-sired. Get the small size with a rimlock case of about 2-1/4 x 3 in. andmount it on the triangular block, as inFig. 11C. Be sure the latch is equippedwith a cylinder which will fit a 7/8-in.thick door. Install latch and strike plateaccording to directions furnished, usinga piece of 1/8-in. scrap temporarily toserve in place of the plywood skin onthe outside.

Attaching the Skin. To cover thebody, we used Vi-in. fir plywood, whichwill bend to conform to framing curvesand bevels. If your sheet is smallenough to handle, place it over a sec-tion to be covered and trim on theframe. You can also prepare a corru-gated cardboard template for each sur-face, trace the pattern on a plywoodsheet and cut it on your work table.

Do one piece at a time, so that futurecuts will allow for side edges of theplywood. Start with side panels andstrips for window trim, then progressto front and back surfaces, and finallythe roof. To attach the plywood, useglue and 3/4-in. bolt nails, which areannular-threaded to hold like screws.If you prefer, use #5 x 3/4-in. fh or rhscrews. Trim off excess plywood aroundwheel wells, rounding off inside comersfor better appearance.

Window Treatment. We used 1/8-in.Plexiglas in front and Mylar transparentplastic film, thin but very tough, on thesides and rear.

Because the Plexiglas is tricky to cutwithout cracking, buy it cut to size,18-7/8 x 20-1/8 in. Center in front opening

by installing between 3/8-in. quarterround strips, as shown in B of Fig. 11.On front framing member adjoining thedoor, substitute 3/8-in. square strip forinside quarter round, as in B of Fig. 11,to facilitate doorstop installation.

You can obtain the semi-rigid Mylarin 48-in. width weather-proofed oneside. Install in side and rear openingsas in detail A-A of Fig. 11, followingthese steps: nail outside quarter roundon all sides of an opening, flush withdoor edge. From inside the cab, holdup a piece of the plastic large enoughto cover opening with something tospare. Attach an end of the plastic tothe top quarter round with 1/4-in. tacks,then curve plastic to shape of panel inwhich the opening is located. In thisposition, carefully trim material to fitopening. Fasten all around, spacingtacks every 2 in. Nail quarter roundagainst inside edges, hiding the tackheads.

Now you can weatherstrip the door.Close it and, with latch engaged, pencila line all around the door frame againstinside edge of the door. Cut lengths of1/2 x 1/2-in. strip to line inside edge ofthe door frame and install them 1/16-in.in back of the line. Use #7 x l-1/4-in.fh screws to fasten all pieces exceptstrip placed against the narrow frontpost and square window stop. Nail thatstrip in place as shown in B of Fig. 11.Space screws about 6-in. apart andcountersink all heads.

For a tight seal, glue 1/8 x 1/2-in. |sponge rubber weatherstrip on the out- 'side face of the 1/2-in. square strip.

Drill 1-1/8-in. holes through wheel• well frame d'rectly over the seat sup-

ports and replace seat For easy access :to the engine, leave rear box open. Youmay need to cut a hole in the rear deckto get at the gas tank. '.

The body can be finished with asealer and exterior paint, or stainedand varnished.

Caution: Before driving your run-about cab on public streets, be sure tocheck your area's requirements forlicensing and equipment, such as lights,horn, windshield wiper, etc. Single ortwin sealed beams can be centered onthe front panel and a taillight installedon rear framing. There's enough spacein the engine compartment for a small12-volt battery. •