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Document DEVICE REPORTWindmill In India 1974

Wind Power
Power transmission: The rear differential and drive shaft unit from a discarded Rambler is the body of the windmill. ft is U-bolted COa steel plate which in turn is bolted CO the pivot bearing. (The drive shaft stub should not point downward or it sill leak oil.)

Blades: The huh with attached blades is bolted to one end of the differential on the 5 original wheel-mounting bolts. Our first ret of blades was designed and built by Bill Smith of Hull Cove. Rhode Island. They were 10 feet dirmcrer. 2-bladed, fiberglass, high-speed airfuilr. designed For 12 mph winds. Their srnrting torque was rather low For our 9 mph average winds, but they worked well and gave very high rpms. We also tried a 3Maded medium-speed canvas sail prop which worked quire well until an ice-storm got if.
Electrical system: We put a belt-pulley on the drive shaft sruh of the differential. and "-heIred i: 12 i.01. auto alternator to if. The differential is geared up ?:I and rhe pulleys 3: I, giving "I P 12:l step-up in rpm From thc'blader to rhe .dtematur. With the turbine blade, this was enough; with the sail hla:!es, more gearing is neeeraary. A 12 volt battery and a regulator are nlounted on the differcutial to chnrge the Field coils; electricity is then tnnsfcrrcd to the ground YiRa cable.
Tail: A plywood fail is U-bolted on the differential opposite the blade end from which the axle hss been rcmoved.
Changes We are switching From high-speed Fihrrglhss air-foils to medium-speed sail wing blades, adapted From the Princeron sail wing studies.' We'll have three blzder instead of two. using aluminum shafts as the leading edge, taut cable as the wailing edge, and dacron wing surfaces. They will trail downwind
of the tower, probably at a slight dihedral angle For added subiiity. Highergearingwill be ncccssary(about LO:,,. but we feel thcr il larger blade diameter (15 Feet), simple construction, and less centrifugal stress will make the test worthwhile.
We are not ready to report on the electronics until the mechanics are completely worked out. From most reports in A/ten&w Sources of E,rer& B simple card running down from rhe generator is an acceptable alternative For slip-rings. needing only to be. unwound periodically. Wr are still debating between a 12 volt or P 120 volt generator; in either case, golfcart batteries will be used For storage because of their ability to take complete charge-dischargecycles and their relatively long life.

If you plan to use an auto differential. leave the brake drum on the hub end with which to stop the blades For inspection and maintenance. It is possible co let the emergency hrakr cable hang down within reach.
SMALL BICYCLE WHEEL. GENERATOR This windmil! is useful where rnvall nmourus of elec-
trieity am needed as in running radios, cartridge players. or in charging storage bnrterier. Ir is ntnde Front P Srurmcy-Archer Dyw-Hub bicycle wheel minus the tube and tire and has R small generator built dire+ into the hub. Eight blades are Formed on the spokeshy attaching sheer metal strips hctwccn adjaccntspokcsfrom the rim 10 the huh. The proper spokes are those which Form slight11 twirring blades nrarly parallel with rerpecr m rhe wheel at the rim and gradually mm to *bout 45" m the wheel at the hub. This shape is favorable aerodynamically IO produce the bigh rpmr For which the generator war designed.
The ;vheel is mounted by one of rhe origins, hub holrs to a simple mecal body nude up of 1 inch of water pipe with a sheet mcfal tail an the other end This is arremhled and wcldcd to a cut-off bicycle Fork and steering besring md atwched to B fwce posr.
Output of iiic geencraroris 6 voh AC. and is changed to 6 dt DC hy a dioilr and a resistor. A dctailcd circuit diqgram and vwknions of hike generator windnGilr arc in the U. N. ener~ conference. Volume 73.

SA"ONl"S ROTOR The Savonios rotor, although only &out half as cffi-
eicnt as it multi-hladcd windmill of the same wind-rwcep arcs, bar scvcra,advantages tbaf mdkc it appropri~tc for home construction nnd we. It spins on a stationary. vertical axis rcgurdlcss of wind direction and it is rhcrefore a simple ms~ficr to take power directly from the rotor shaft. If is very simple and cheap to conrfruc~ Adjusting the diameter of the rotor wings varies the rate of spin in identicil, arcas and wind?pccds.
Our present Savonh~sram is P variilfion of the Hraee Rcscarch :nsfifufc's design5. "ring 55.gallon steel drums cot lengthwise and welded into two off-w cup-shaped blades. Rcarings at top and bottom in B guyed wooden frame complete the rotor. (A few hints: Use 4x4 inch lumber for the frame; balnnce the rotor carefully; and wire the turnhucklcs when tight as they can vibrate l""SC.)
We coupled this system to a reciprocating wire power transmission, which was originally used by the Pcnnq4vania Amish to transfer power from a wwcerwheeld, in

In man) parts of India including Tim's farm rhere WC ndcqu~rc supplies of ground water which we enavailable to farmers during the dry sc~son because of inndcquate power sourcesfor pumping. Three to cigbt liorsepowcr diesel pumps arc frequently used bur arc expensive CO operate because of the high cwf of imported oil and ofren must hu taken out of rewire for costly and timeconsuming repairs. Efficient five horsepower electric pomps arc being used more and more as rural elec:rification proceeds, hut only well-to-do farmers can afford to buy and maintain them. This winter in South India there was P 75% power cuc fo the rural ~-CDSdue IO heavy consumption in the cities and to ovcrcxpsnsion of the power grid without a corresponding increw in sup-

ply. This powrr shortage meilns chat there are only four hours of electric pumping per day. `This situntion is expcctcd to worsen for the next iour 10 five years until the lndian Government beginsopcrrtion of atomic power plants in South India AT the prcscnt time hullock operated pumps remain the most commonsand rcliable source of irrigation wafer for subsistencefarming. V&WC <or domcrcic use is usually hand-lifred with B rope and bucket from open welfr.
During the early 1960`s rhe Wind Power Division of the National Aeronautical Laboratory in Bangalore, Mysore. dcvclopcd. rested and produced two hundred 12. bladed fan-cypc windmills which demonstrate the fcarihiliry of using wind power CO pump water to Swth India. Scvernl types of ibnportcd European and Americm ~multiblxled windndllr have also hem wed to harncs~ India's rbundanr wind energy resources. Howrver. due to lack of public nw;1rceessaed dw unavailability of simple and inexpensive devices. wind powrr is only occ*simally cxploitd
With these rboughtr in mind I returned to the States for one yew. While working ar the New Alchemy farm a,, Cape Cad, Earlc Bsrnhart and I built and rested a three-bladed cloth sail windmill which appeared to ix simple and efficient em@ for prarticnl use on Tim's ftwm.
Cloth sails with a wooden framework have been used for hundreds of years for rranrforming the useful cneqy of the wind into labor-raving mechanical work. especially for grinding grain and pumping wuarer. The USCof windmills spread from Iran in the seventh ten,,,`y A. D. ro cmsm, China whr:e rhc applicarion of the art of sailmaking significantly improved the sophistieation of windmill construction. Heavy rigid wood wind-

mill blades surfaced with cloth were used increasingly throughout northwestern Europe and hy the seventeenth century the t:ctherlmds had become one of the world's richest and most indusrrializcd nations largely as a ccsub of extensive exploitation of windpowcr with ships and windmills. Cloth wa a natural choice for windmill sails because of its acceptance and wide use in sailing ships. It is ligbtwclght, easy to handle, readily and chenply available, End most ibnportant, if forms a strong uniform surface for catching the wind when firmly supported at three or more points.
In the Mediterranean region flour-grinding and oilpressing mills were rigged with six m twelve triangular cloth sails sei on simple radial spars. A three ~limcnsional arta> c;f guy roper radiating from a ccntra, spar projccriug out along the axis of the main shaft, WIpcnded the sailsin position. rather tlum the heavy grid ef wood ured in the traditional Dutch-type windmills. `This sailboat jib type of rigging was a rignificmt improvcmcnt in windmill design which encouraged the spread of windmills througkout the deforested Mediterranean countries. The wind capturing area of these windmills was controlled by wrapping each cloth sail around its spar. Though requiring daily rigging odjustmcntr and occasi.mal replacement of tattered rails, the rfficicncy and simplicity of thesewindmills resulted in their widespread use in Rhodes, the Black Sea coa,st, the Acgezn lnlands and Greece. In Portugal their use was accompanird by
the sound of whistles attached to the rigging. an audible indicator of the wind at work. In the West Lndier large Failwing windmills were commonly used for crushing sugar cane. Many kandctaftcd windmills with eight triangular jib sails a'c presently Pumping irrigation wat,er in the Plain of Lassithi, Crete. In Japan four-bladcd jib rail windmills ate used to operate reciprocating pumps which supply water to vegetable gardens. A high-speed aerodynamic two-bladcd sail wing is being developed at Princeton University. Further construction rimplifications may make it applicable to use in less dcvelopcd countries.
A windmill with four self-adjusting cloth sailshasbeen developed by Mt. H. Stam for rural markets in less industrialized regions. Its relatively complex design is limited beeawe of the difficulty in connecting it to a deep well pump, Unfortunately, it cannot be manufactured by hand using local materials. Those people who arc in a situation to most benefit from a windmill are also those least able to pay for it. If the critical moving parts were scparntcly avaiiahle. a small farmer could purchase the remaining materialr needed and assemble the windmill in his own village using local skills and labor. This way e major portion of the money spent would remain in the vI!!q
Upon returning to India this wintct I discussedsome of the problems of building a small practical wiadpowwed pump with scientists at the Indian institute of Agricultural Research in New Delhi. It was suggestedthat I

seemup the windmill that I was planning for Tim's farm with a modified paternoster pump like those used to drain mines in England many yerrs ago. I ws given a working demonstruion of some chain pumps in the 1. A. R. 1. and was told that a chain pump is easily and cheaply built md has the advantage of being more efficient than most other types of pump. Unlike some other pumps it upcrater well with a low sped variable power source like .a windmill. Recently chain pumps have been replacing the traditional square paiiet Pump and cbc Noria water iifting wheel tbroughOUI China.
My friends in Delhi wished me good luck and I metrily proceeded on a delightful three day train ride by third class coach to the southern tip of the Indian subcontinent. I arrived at Tim's farm and WC soon began conatrwtion of the windmill.
Thin sail wing windmill is made of a onwnetcr dismeret bullock cart wheel to which three bamboo poles are loshed in a triangular pattern with overlapping ends. Exb bamboo pole farms the leading edge of a wing, and a nylon cord stretched from the outer tip of the Pole to the rim of the wheel forms the trailing edge. A ruble and lightweight airfoil r~wlts from stretching a long nmow rriangnlar cloth sail over that bamboo-nylon frame. This wing configuration. a hybrid of low-speed
eight-bladed Cretan sail wings and high-speed two-bladcd aerodynamic sail wings, producer high starting torque at low wind speeds. The bullock cart wheel is attached at the hub to the end of an automobile axle shaft which :ofafcs in two sets of ball bearings. The shaft and hcaring assembly is mounted horizontally on top of a turntable. The turntable consists of two circular see, plater separated with a raceway of hall bearings and held together with a ring of eight bolts which encircle the hottom plate. A one-foot diameter hole through the center

of the turnclhlc will lN"W Ibe chain and gaskets of the ,: chh pump to go up and around the "squirrel es&
which is mounted itt the ecntcr of the ato BYIC. If a j:I;:,I reciprocating deep well piston pump were d&cd. the
:, reciprocating rod, rather than a chain, would go through this hole and the crankshaft rather than ata uxle shaft
,' would he mounrcd on top of the turnmblc. Since the blades have n slight built-in eonhg cffcet and the axle or crankshaft is mounted rligbtly off center from the center line of the tumrahlc, the htadcn net as their own tail, trailing in the wind. Because the blades arc downwind from the tower. them is no danger of the bamboo poles bending in a monsoon wind and hitting the towct. The tower is made of fire 25.foot-long teak poles set in concrete at the base and bolted a? the top to five angle irons welded at a slieht flaring angle to the bottom of

the turntnblc. `The tower tapers in towards the turntable at the top from a sewn-foot diamctcr at the base. It has cross bracing and a ladder.
This cightmctcr dismctcr windmill lifts three hundred pounds to a height uf twenty feet in one minute in a ten mph wind. This is accomplished by a rope passing over J six-inch pulley on the main drive shaft. This lift is now being used to raise soil and rock from the 20.foot deep well which is being dug below the windmill. When the well is finished the pulley will be replaced by the "squid cage" of the chain pump.
t hop that other people will eontinuc to refine and adapt this windmill to their own needs and materials. If you have any inquiries or suggestionsfo: improw mcnt. I will be pleased to reply.
- "l^-.-.." u cl.-.."..

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