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MOTORGLIDING

Donald P . Monroe, Editor

Vol . 4, No . 5

Published by The Soaring Society of America, Inc .

May 197 4

Contents Page

FIRST INTERNATIONAL MOTORGLIDER COMPETITION-BURGFEUERSTEIN June 8-16 1974, by Peter Ross 2

FOREIGN SCENE, by S . O . Jenko 8

LEARNING TO SOAR WITH THE RF-4 Dby Landon Cullum, Jr . 1 1

POSTFLIGHT NOTES 1 4

CLASSIFIED ADS 14

Cover : Graham Thomson LTD's Scheibe SF-28A Tandem FaZke atEl Mirage, by Donald P . Monroe

Motorgliding is published monthly by The Soaring Society of America, Inc ., whos eoffices are at 3200 Airport Avenue, Room 25, Santa Monica, California 90405 . Themailing address is Box 66071, Los Angeles, California 90066 . Subscription to Motor-

gliding is $5 .00 ($6 .00 outside of U .S .) for one year {12 issues), beginning wit hthe current issue .

Back issues are available at 50¢ each .

Second-class postagepaid at Santa Monica, California . Reproduction of any of the material printed i nMotorgliding, unless specifically excluded, is encouraged . Readers ' may wish to cor-respond directly with Harry N . Perl, Chairman, Powered Sailplane Committee, 390 7California Way, Livermore, California 95440 ; or Richard Schreder, Chairman, Air-worthiness and Certification Committee, Box 488, Bryan, Ohio 43506 .

ADVERTISING RATES, CONDITIONS, AND SIZES

Display ads :

$15 for a page ; $25 for ½ page and $40 for full page . Prices are forfull-size, photo-ready copy . Extra charges for make-up, $3 .00 to $5 .00 ; reductions ,$2 .00 ; and photos, $2 .50 .

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Classified ads : 50$ per line (40 characters )or portion thereof .

Circulation of the April 1974 issue was 960 . This issue was mailed in October 1974 .

1

FIRST INTERNATIONAL MOTORGLIDER COMPETI-

class 18-meter Cirrus, and successfull yTION-Burg Feuerstein June 8 - 16 1974

competed in this for two years (this par -by Peter Ross

ticular prototype has recently come t oBritain and is being flown by Brenni g

This year the annual meeting for mo-

James) .

Collee and Obermeyer worke dtorgliders was again held at Burg Feuer-

closely with Holighaus in the design o fstein in the Frankischer Schweitz region

the same engine into the new powere dof Germany, between Nuremburg and Bay-

Nimbus .reuth . To mark the 50th anniversary of

Also of great interest was a Stan- .motorgliders it was this year given the

dard Cirrus {which together with th etitle of an international competition,

Libelie and the AS-W 15 represent th eand attracted entries and/or pilots from

most widely used and competitive standardthe USA, Denmark, Austria, Switzerland,

class competition sailplanes), fitte dand the United Kingdom as well as a large

with the same retractable engine instal -entry from West Germany .

lation as used on the Nimbus . Although

The increased interest in motorgli-

seen briefly a year ago, it had just bee nders was underlined by the presence of

completed, and literally made its firs tthe West Germany world record holder and

flight on the second day of the meeting .competition glider pilot Hans-Werner

Takeoff and climb were impressive .

TheGrosse, who flew a motorglider for the

significance of these two sailplanes isfirst time only a few days before the

that for the first time no sacrifice iscompetition started, and was competing

made to performance, and the current topin the advanced two-seater class flying

gliders in both standard and open classesa Schleicher AS-K 16 with designer Rudi

are now available with self-launching andKaiser as co-pilot .

In previous years

self-retrieving capability .

The weightwe have seen two world champions {Ernst

of the engine installation is in eac hGunther Haase and Heinz Huth) taking

case less than the weight of water bal -part, but this is the first time that a

last that may be carried . The only pen -current top competition glider pilot has

alty would be in weak lift condition sbeen involved .

when the pure sailplane would not carry

The most exciting development at

water ballast .Burg Feuerstein was the first appearance

On both these designs the raisin gof the new Schempp Hirth Nimbus II with

and lowering of the engine is carried oncompletely retractable 50-hp Hirth en-

electrically, using the motor and rack-gine, which has been developed under the

and-pinion from a Bosch car sunroof in-personal direction of designer/competi-

stallation .tion pilot Klaus Holighaus, himself a

The competition itself was againmember of the West German international

divided into three classes . Class 1 wasgliding team .

This development can be

for advanced single-seaters, and includedtraced back to the first German retrac-

the Nimbus, the SF-27M andthe Schleichertable-engined single-seater, the Scheibe

AS-K 14 . The AS-K 14 is normally fitte dSF-27M which started as a prototype when

with a four-cylinder 26-hp Hirth hori -Alois Obermeyer modified a Standard Class

zontally-opposed two-stroke engine, bu tSF-27 sailplane .

The design was taken

one was fitted with an experimental Wan -up and further refined by the Scheibe

kel engine made by the Sachs company .factory, and was put into production .

Class 2 wasfor advanced two-seaters, an dSeveral were flying in the competition

in addition to the previously mentionedin the advanced single-seater class . The

AS-K 16, included the Sportavia RF-5 Bdevelopment was continued in the hands

Sperber, the Scheibe SF-28A Tandem FaZkeof Willibald Collee who used an SF-27M

(which took the first four places lastas an engine test bed to develop a more

year), the new new Scheibe SF-25E Superpowerful two-cylinder two-stroke engine

FaZke which has 18-meter wings whic hwhich was being produced by the Hirth

fold like the RF-5, a more powerful 70-company as a power unit for snowmobile

hp 1 .9-liter Limbach engine and a claimedracing in Canada .

He next commissioned

gliding angle of 1 in 29/30 ; and two pro-the Scheibe factory to produce an SF-27M

totypes based on the Bergfaike IV tw* -

with the fibre-glass wings from the open

seater sailplane (which has a glidin g

2

i

angle of 1 in 34 in the pure sailplane

specified height .

His flight time wasconfiguration) .

three hours and ten minutes . The second

The first of these was fitted with

two-seater was the RF-5B Sperber flowntwo Lloyd two-stroke engines in the wing

by Manfred Schliewa who carried a light-roots, a development of the Schleicher

weight passenger and very little fuel ,Ka-8B seen in previous years which is

who used 13 .1 minutes of engine and tookfitted with a single Lloyd engine in the

4 hours and 13 min .

Third of the two -starboard wing .

This, like the Ka-8B,

seaters was Hans-Werner Grosse in th ewas beautifully engineered, and the en-

AS--K 16 who used 19 .2 minutes of enginegine installation appeared to give little

and took 3 hrs 6 min .additional drag . It took off and climbed

In Class III the leading competitorwell, but produced a very loud noise

used 22 .2 minutes of engine, and did no twhich might be unacceptable on environ-

score sufficient points to allow a corn-mental grounds at some airfields .

petition day to be declared .

This is a

The second BergfaZke IV was fitted

good example of the way in which the or-with the same Hirth two-cylinder engine

ganizers have developed the rules ove ras in the Nimbus, but mounted fixed on

the years, because when a lot of engineits side in the fuselage and driving a

is used it gives an unfair advantage tolarge propeller through a very long cog-

the motorgliders with powerful engine sged belt giving a 4 to 1 reduction . The

which can both climb and cruise furthe rdrive was through a Hookes joint, so ar=

for every minute of engine .ranged that the pivot of the retractabl epylon coincided with the center of th ejoint which allowed pylon and propelle rto retract into the fuselage even thoughthe engine was fixed .

Class III was for less advancedsingle- and two-seaters, which containedthe Ka-8B, Scheibe SF-25B Falkes with45-hp Stamo engines with both manual and

PHOTO CAPTION Selectric starting, SF-25C and C-S Falkes

(pages 4-7 )with 60-hp Limbach engines, the latte rhaving a feathering propeller, retrac-

1, 2 . Powered Standard Cirrus .table cooling flap, and improved rear

3 . Scheibe SF-25E Super FaZke .fuselage shape to get better airflow at

4, 5 . Powered Standard Cirrus .the wing root .

6 . BergfaZke IV, fixed eng, retr prop

The first competition day was one

7 . Twin-engine BergfaZke IV.on which no normal gliding competition

8-10 . BergfaZke IV, fixed engine .day would have been possible .

The sky

11 . AS-K 16 .was completely overcast, yet a 100-km

12 . AS-K 16, Rudy Kaiserout-and-return was set for Class III,

13 . Sachs-Wankel AS--K 14 .and a 130-km out-and-return for Classes

14 . Twin-engine BergfaZke IV.I and II .

15 . Underwing detail, BergfaZke IV twin

For the Class II competitors it was

16 . Overwing detail, BergfaZke IV twina case of pressing on, and using hill

17 . Twin-engine BergfaZke IV .lift wherever possible, and an occasional

18 . SF-25E Super Falke.thermal towards the end of the flight .

19 . SF-28A Tandem FaZke .Classes 1 and 2 did rather better an dKlaus Gshwindt, flying an AS-K 14, di dexceptionally well to complete the cours eusing only 2 .2 minutes of engine . I ttook him four hours and ten minutes . Hebeat the best of the two-seaters, th enew Super Falke, flown by Rudolf Wilschwho used ten minutes of engine but wa spenalized three minutes for arriving a tthe finishing line below the minimum

3

4

6

1 7

1 8

19

7

FOREIGN SCENE

landing gear was added to provide inde -pendence on the ground .

The wings wereby S . O . Jenko, Dipl . Ing . ETH

retained from the original design .AMTECH SERVICES

This new design (1970) was namedAustria Kraehe and an approval for fligh t

In the past issues of Motorgliding

testing was received from the Austria none can find articles by Tasso Proppe

aviation authorities .

During the sameabout his auxiliary-powered sailplane

year the son, H . Brditschka, Jr ., corn-Kraehe (Crow) and the many flying excur-

pleted his training in aircraft tech -sions . Months ago there was also an ad-

nology .

These two events resulted i nvertisement with an illustration of the

creation of a new aircraft products de -"new" Kraehe, now in production . An in-

partment within the company of H .W . Brd-quiry finally produced an interesting

itschka .description by the manufacturer about

By 1971 a second prototype was corn -the development of the latest models .

pleted and flight tested .

The engineThe story resembles somewhat that of the

was a two-cycle Rotax . Steps were under-Kora I (see Motorgliding, March 1974) .

taken to obtain the type certificate asA slightly abbreviated translation of

well as the necessary financial means t omaterial supplied by the manufacturer is

ease the burden on the main company .presented here .

The year 1972 saw considerabl e

The area southwest of the Austrian

activity : a third prototype with a Puc htown of Linz is the new home to many Ger-

engine was built, incorporating all theman refugees from Sudetenland .

They

features of the production model ; also abrought with them their craft--the manu-

second pre-production plane was corn -facture of ornaments . One of the better

pleted .

Furthermore, it was decided t oknown companies in this field is H . W .

use Austria Kraehe as a general nameBrditschka ; their products can be found

only, the type designation was HB-3 ,throughout the world .

consisting of :

HB-3AR, having wings o f

The owner-manager, Heinrich Wenzel

the Raab's Kraehe and a Rotax engine ;Brditschka is an enthusiastic sportflyer

HB-3BR, having new, stronger wings and ain his spare time . During 1960 he began

Rotax engine ; HB-3BP, having new,strong -to build the Kraehe, the first to be con-

er wings and a Puch engine .structed in Austria, using the plans

It was also decided to develop aprovided by the designer Fritz Raab .

two-place version, HB-21, and a high per -This design featured an opening in the

formance singleplace design . To carrytail truss where it was attached to the

out this project the wing panels of thefuselage pod, thus providing room for a

Swiss B-4 sailplane were acquired .propeller .

The flying group consisting of some

In 1964 H .W. Brditschka and F . Raab

employees of the company began to buil devaluated the experience gathered with

a HB-3 in their spare time .

Thus thethe Kraehe and began to design a new aux-

suitability as a homebuilder's projec tiliary-powered sailplane .

Based on an

was demonstrated . In early part of 197 3idea by F . Raab, H . W . Brditschka de-

the kit became available as HB-3BR .signed a bearing for the propeller shaft

The flight tests of HB-3 were als owhich at the same time serves as the up-

completed during the beginning of 197 3per tail truss member .

Thus a larger

and the work on the prototype of the two-diameter propeller (approximately S ft)

place version, HB-21, got under way .could be used . This new arrangement was

Another project, the application o fpatented .

electrical energy, was initiated by F .

In addition, the fuselage pod was

Militky in cooperation with known manu -completely redesigned and a tricycle

facturers Varta (batteries) and Bosc h

8

(electrical equipment) . During the autumnof 1973 the second prototype of the HB- 3was converted to electrical propulsio nconsisting of four batteries and an elec-tric motor of 8 kw, providing power fo rabout six to eight minutes .

On October 21, 1973 the first elec-trically powered airplane, an auxiliary-powered sailplane, was airborne and land -ed 10 minutes later . The flight testingcontinued and flights of up to 12 min-utes were achieved .

This project was designated as MB-El .The gross weight of the HB-3A was in-creased to 970 lb and the correspondin gwing loading was 6 .4 psf . The weight ofthe 8-kw, 2400-rpm motor was 73 lb : thedischarge potential was 120 volts at 22 0amps . The propeller static thrust wa s171 lb which decreased to 143 lb after 6minutes of operation .

Engine compartment of MB-E l

The possibility of electrical powerfor use in auxiliary-powered sailplaneswas demonstrated . However, the practi-cability will depend on further develop-ments in the storage technology of elec-trical power-smaller battery weight ,larger capacity and a more reasonabl ecost .

(A detailed account of this appli-cation is presented in an article b ynoted aeronautical engineer and soarin gpioneer, Dr . Ing . Alexander Lippisch ,published in the June 1974 issue of SportAviation.)

Technical Description of HB-21 (two-place) and HB-3 (singleplace) auxiliary-powered sailplanes .

The information presented here i staken from the manufacturer's pamphlet .

The HB- auxiliary-powered sailplaneshave STOL capabilities . The specialthrust-propeller system provides excel-lent performance on takeoff, duringclimbing and cruising, using less powe rthan other auxiliary-powered sailplanes .With engine off they also feature goo dsoaring performance . The cockpit isspacious and the canopy provides excel-lent visibility .

The engine and propeller are locate dbehind the cockpit, eliminating the in-convenience of a conventional exhaus tsystem and also diminishing the engin enoise . The propeller is protected by th efuselage ; the engine consumes only abou t3 .5 gallons of gasoline per hour .

Complete independence on the groun dis achieved by a tricycle landing gea rfeaturing fiberglass struts .

The wing consists of three panel sof wood construction with the usual "D"nose to take care of torsional loads .The fuel tank is located in the nose ofthe center wing panel .

The tail is made of wood, as is thetail truss which connects to the fuse-lage pod . Its position is held by teth-ers to the wing .

The fuselage is made of steel tub-ing with a fiberglass cover . The enginecompartment is behind the cockpit separ-ated by a fire wall . V-belts transmi tengine power to the propeller shaft lo-cated behind the wing . As mentioned pre-viously, the upper tail truss memberalso serves as the propeller shaft bear-ing .

4IMIb

*Silad..

1

HB- 3

L„_1

Technical Data

HB-21R

HB-3BR

Wing span

53 .3 ft

39 . 4Wing area

204 .3 ft 2

153 . 1Aspect ratio

13 .9

10 . 1Length

25 .9

2 3Height

8 .5 ft

7 . 3Empty weight

800 .3 lb

573 . 2Max . gross weight

1322 .8 lb

837 . 7Wing loading

6 .5 psf

5 . 5Best glide ratio

28

20at

62 .5 mph

49 . 5

-

- . ...*

**-_-

/

PR-2 1Min . sinking speed 146 ft/sec 226 Engine : Bombardier ROTAX 642, develop -Ground run 558 ft 328 ing 42 hp at 5000 rpm,

weight 92 .6 lb ,

Take-off distance 820 ft 755 2-cycle, electronic ignition,

electri cRate of climb 433 ft/min 590 starter .Cruising speed 99 .2 mph 93 . 2Max .

level speed 108

mph 9 9Max . diving speed 146

mph 108 HB-21L features a VW Limbach 1700 EF en

Stalling speed 41 .5 mph 36 .8 gine, developing 60 hp .

Range (full tank)

43 5Service ceiling

13,000miles

31 1ft

13,125 HB-21R and HB-21L have 69" diameter pro -

Fuel consumption

2 .8 gal/hr

2 .6 pellers .

i

1 0

LEARNING TO SOAR WITH THE RF-4 Dby Landon Cullum, Jr .

I became involved with the delight-ful little airplane known as the RD--4 Dby somewhat of the back door . A friendand I took a quickie vacation in Colo-rado Springs to get a taste of glidin gand glider licenses to put on our tick-ets . Predictably, we got somewhat hookedand on my return to Wichita Falls, Texas ,I started looking for an outlet for th erecurring urge to fly gliders . As nogliders reside here, I ran down the FortWorth and Dallas organizations, but foun dthe time and effort required practicall yoffset my desire to glide in spite o fthe good organizations available there .Access to a PA-18 and a couple of climb sfrom 3500 to 7000 in selected north Tex-as thermals started me thinking abou tindependence and soaring, and a quicklook at an RF-4D that passed throughstarted me looking . Back in 19721 caughtDick Hodgkins in a weak moment and paidwhat I thought at the time an exorbitantprice for his RD-4D . Why, I could havehad a first class 1-26 and trailer fo rwhat I put into that part airplane-par tsailplane mixture !

Then the education began . The lit-tle jewel began to teach me what rea lfreedom is in gliding . After a coupl eof months cleaning things up, doing need-ed repairs, and adding an oil cooler t oplacate my nervousness at seeing oi ltemperature go by the redline, it sud-denly became the most trouble-free air-plane I've ever owned and is a sheer de-light to fly . My Seabee and EAA biplanebegan to gather dust in the back of th ehanger . After losing much of the firs tsummer's soaring waiting on a new pro p(after a gear-up landing to which I con-tributed by launching a friend before Ilocated an intermittent gear warnin gproblem), I took a long cross-country to0skhosh and found it to be a joy fo rtravel if you are going alone and light .Over 100 mph in cruise at nearly 5 0miles/gallon is hard to beat for effic-iency, too .

Its real value to me is, however ,in another area . It has given me com-plete freedom to enjoy and learn abou tsoaring flight with no dependence on any-one else : no help needed to get it outor put it up, no effort or help gettingto the runway, no towplane, towpilot ,ground crew, trailer, retrieve crew and

especially no time lost in arranging fo ror gathering all that up . I can decidein the office at 11 :45 to fly instead ofeat, drive to the airport in 20 minute sand be airborne by 12 :20 . With luck (ora few air starts) one can soar an hour ,and be back on the job before 2 :00 . Orleave at 4 :30, fly and get home for a6 :30 dinner-reliably if need be . Sure ,many of the lunch-hour quickies turn int olong delightful afternoons, but the poin tis that I can get in the flying and getback reliably, if necessary, without ad-vance preparations .

This sort of testimony to power gli -ders may be unnecessary in Motorglidingto those who have them, but there mus tbe many readers who don't have access t othem if there are 920 subscribers . I nspite of the fact that I agree with Char-lie Webber that the RF-4D is a super blittle airplane but a lousy glider, Ithink it has much to offer sailplane en-thusiasts .

The other real value of the RF-4 Dto me has been in speeding up my learn-ing process about soaring . I really be-lieve that Iwould have learned about 1/ 5or so as much if I had purchased a 1-2 6and allotted the same time away from homeand business to it as I have the RF-4 ..Easy one-man operation gives you muchmore actual flying . Independent trave land return capability lets you check ou tdistant terrain, cloud formations o rwhatever, and allows you to-make mistakesin finding and working lift withou tspending most of the time getting towedback up . The little VW glide-flattenerup front can also do wonders in increas-ing your capability in experimenting withweak lift when that's all you've got .You can "check out" a thermal befor eshutting down in ways that are downrigh timpractical on the end of a tow rope .Of course, you give up some things fo rthis flexibility . I haven't learned much ,about thermaling below 1000 ft, and I' mnot nearly as current as an active 1-2 6pilot on "out"landings .

So much for the commercials . Basedon my experience in north Texas and wit honly 15 hours in regular non-power gli-ders, just what will the RF-4D do? M ymeasurements indicate it glides 17 to 1at 60 mph and has a sink rate of 270 ft /min at 52 mph . (Prop does not feather) .In gliding capability forme this resulte din the following performance in 1973 .

11

MonthNumber o fFlights

Engine-onTime-Hr

GlidingTime-Hr Remarks

Jan . '73 2 0 .7 0 .4 Little or no altitude gain .

Feb . 5 3 .8 1 .2 1000' on I flight, usually none .

Mar . I 1 .0 0 .2 No gain, rapid descent .

Apr . 4 2 .3 3 .4 500 - 1300 foot gains .

May 7 3 .1 2 .6 1000'

on 1 occasion .

Jun . 4 2 .7 3 .4 Min .

800', max .

4000'

climb .

Jul . 7 3 .0 9 .6 Gains to 4000' on 3 of 7 .

Aug . 9 2 .7 8 .5 2000 to 4000 foot gains on 7 of 9

Sep . 5 3 .2 3 .2 1000'

or less typical .

Oct . 7 4 .0 1 .7 Little gain-just reduced sink .

Nov . 1 1 .5 0 Cross-country travel .

Dec . 3 1 .3 0 No gliding--little or no lift .

(Note : Engine on time includes idle time as well as low power time on wea k

days-probably about ¼ of total engine time .) (Totals are 29 .3 hours power ,

34 .2 hours gliding or 63 .5 hours flying on 57 gallons of gas . )

As results show, most of the tim eyou are working to stay up in the RF- 4and restarts are pretty common on man yflights . Starts have been 100% for mebut on two instances friends have landedpower off (on the airport) after on estart try failed . I operate on the basi sof 1500-feet AGL minimum glide altitud eallowing 600 feet for a dive to restar t(110 IAS) and 900 feet for pattern an dfield selection if it ever fails . Aswith any glider my altitude determine sto a large degree what terrain I wil lfly over .

Obviously, gliding performance wasn' tspectacular in 1973 for me . I tried fouror five out-and-returns to the town o fArcher City-15 miles away, and neve rdid manage to make it back without a re-start . I think pilot performance was abig factor, however, and that the RF- 4was teaching me as best it could .

In1974 this began to show .

By June I hada few 5000-foot climbs and one of 700 0feet .

On July 14 I caught a great daywith 10,000-foot cloud bases and flew anout-and-return to Olney airport . Th eround trip was 72 miles with three climb sto 10,000 feet after my 3000-foot MS Lstart for a speed of 28 mph . Climb rate sat times exceeded 700 fpm so condition s

were quite strong .About this time the SFS-31 owned b y

the Berg estate was advertised for sal e

and I bought it . It is just like theRF-4 except for the 50-foot wing butflies quite differently . It isn't nearl y

as responsive or light on controls a sthe RF-4 but is a far better sailplan eand retains the complete one-man opera-tion capability that has made the RF-4

so valuable to me . So far I haven' tmeasured its performance for a technicalcomparison, but my impression is that itmay be as good as the factory says : 2 9to 1 and 170 fpm .

We are still getting acquainted ,but in 10 flights here since July 30th Ihave run the engine only for launch ,never had to restart because of altitude ,and landed each time at my option . Theflights have included climbs from 240 0feet MSL to 10,600 feet MSL in thermal sand an out-and-return of 70 miles at 3 2mph with a very strong headwind outbound .I have run the engine 1 .5 hours and gli -ded 16 .8 hours . Conditions have beengood, so I'm sure this won't last . How-

ever, on a number of flights, friends i nthe RF-4 were unable to stay up and a2-33 was unable also on one occasion .

My feeling is that motorgliders arehere to stay and should become a stron gand healthy factor in soaring in the U .S .Even though the initial cost is high ,the economics and use factor would, Ibelieve, make them very competitive nowif the regulations permitted their com-mercial use . I also feel that in condi-tions such as exist here in north Texassomething in performance between th eSFS-31 and the RF-4 would be quite ade-quate, just as the 1-26 seems to mee tthe needs of a large segment of the pur e

sailplane people . Reasonable cost and

self-sufficiency are more important i nmy viewpoint . Hopefully, sometime soon ,breakthroughs in the regulations and a

certifiable engine will make this de-lightful side of soaring available t omany more Americans than the lucky few

of us now so blessed .

12

Contest winning performance at a reasonabl eprice, plus docile handling characteristics an da worthwhile range under power (about 28 0miles) mark the Tandem Falke as today's bestvalue in self-launching sailplanes . The 60 hpLimbach engine with a Hoffman featherin gpropeller provides plenty of power to operatefrom regular airfields .

Engine-on Performanc e

Takeoff run 500/650 ft .Rate of climb (sea level) 430 ft ./min .Maximum speed (sea level) 106 mp hCruising speed 81-93 mp hEndurance (cruise) 3 hoursFuel capacity 7 1/2 gallons

Gliding Performance

Maximum glide ratio 26/27 to I at 53 mp hMinimum sinking speed

2.95 ft ./sec. at 43 mph

The Tandem Falke's outrigger wheels andsteerable tailwheel allow completely inde-pendent operation . With its outrigger wheel sremoved the Tandem Falke may be conven-iently hangared with other sailplanes .A side-by-side version is available for pilot swho prefer this arrangement. Similar perform-ance, but slightly lower rate of climb and glideratio . Order the SF-25CS "Falke ."

Prices include flight test, German certificateof airworthiness, flight and engine instruments,electric starter, feathering propeller, cabi nheater, upholstered cockpit, two-tone paint ,packing, sea crate, and shipping to the portof Hamburg :Scheibe SF-28A Tandem Falke DM 49,800

FOB HamburgScheibe SF-25CS Falke DM 49,000

FOB HamburgDelivery, approximately five months from order .

GRAHAM THDMSDN LTD3200 AIRPORT AVENUE

SANTA MONICA, CALIFORNIA 9040 51213) 398-4714

Sole distributors of Scheibe powered sailplane sin North America

MotorgZiding

Second Class Postage Pai dc/o The Soaring Society of America, Inc .

At Santa Monica, Calif .P .O . Box 66071Los Angeles, California 90066

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POSTFLIGHT NOTES

fornia .

Vern may offer plans in th efuture . We hope to have an article from

September 7, 1974 was an excellent

him in an early issue of MotorgZiding .soaring day in southern California's

The Chico (California) Soaring As -Mojave Desert .

While I was exercising

sociation has imported a two-place Frank-my Standard LibeZZe on a 200-mile out-- ., lin-powered Slingsby T61B (a one-of-a -and-return flight from El Mirage (an

kind FaZke, built under license,the onlyaborted, 500-km triangle attempt), I oc-

one so-powered) .

They thus become thecasionally heard 'Two Eight Alpha' on

first U .S . club that we know about. to123 .3 .

I didn't realize it until a few

give gliding training in a motorglider .days later, but Graham Thomson had taken

Read about their experiences in futur eoff from Santa Monica Airport, . where he

issues of MotorgZiding .bases his Tandem-FaZke, and, after 40

SSA Director ..Floyd Sweet and sevenminutes of engine time, which took him

others have purchased a SF-25B and hav eto the mountains south of Palmdale, pro-

been operating it at Frederick, Maryland .ceeded on a soaring flight to TwentyninePalms and then to Apple Valley-over 20 0miles .

Quite a flight .

From Santa

CLASSIFIED AD SMonica '

Graham reports, incidentally, abso-

DESIGNING & BUILDING your own aux -

lutely no problem in operating from busy

iliary-powered sailplane and in need o f

Santa Monica Airport .

sound engineering advice?

For free de-As noted in October Soaring, Vern

tailed information send a self-addressedOldershaw dropped by the office the other

stamped envelope to : Amtech Services-mg ,day and demonstrated his powerplant-re-

RD 8, Mansfield, Ohio 44904 .tracting prop . He had returned from theEAA Oshkosh fly-in where he had won the

SF-27 .

No motor, excellent condi -Stan Dzik Memorial Award for his Out-

tion, Bayside 990, fully instrumented ,standing Design Contribution, described

oxygen, trailer and cover . ATC . $7700 .as a retractable sailplane power head .

Gunnar Anderson . (707) 996-8027 .The powerplant is a 443-cc Yamaha snow-mobile engine .

The unit produces 32

Sport-Aviation Inc .

SEASON CLOS Ehorsepower and weighs 124 pounds, al-

OUT .

RF-5B Demonstrator, 490 hrs TT .though Oldershaw says he can reduce that

Radio $ audio-vario . Fully instrumented .by about 20 pounds .

The prop has a 42-

$22,000 . First used unit ever available .inch diameter and a 33-inch pitch and

Also RF-5B brand new . 1974 model at 197 4was made by Les Trigg, in the Los Angeles

prices, fully instrumented with radi oarea . The unit is to be installed first

and electric T&B, electric audio-varios .in an Oldershaw 0-3 under construction

Beautiful white with red trim . (216)by Carlton Kibler, in Porterville, Cali-

262-8301 .

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