MOTORGLIDING

MAY 1973

YEAR AROUND * I ECO OMYUTILIZATION

IF YOU WANT MORE ENJOYMENT FOR LESS COST

FLY A POWERED SAILPLAN E

Type

SFS 31

L/D Cost Seats HP

RF 5 B

Engine Rt . SinkSpan Delivery

RF-4D '37 ft 20 $11,360 6 month Single 36 VW 4 .0 ft/se c

SFS-31 49 ft 29 12,800 6 month Single 36 VW 2 .8 ft/sec

RF-5 46 ft 22 17,040 6 month Dual 68 VW 4 .6 ft/sec

RF-5B 57 ft 26 17,700 6 month Dual 68 VW/Frank 2 .8 ft/sec

Standard equipment includes : Airspeed indicator(s), Altimeter(s), Variometer(s )

Magnetic compass, Gear warning light and horn, Safety harness(s), Seat cushion(s) ,

Tail antenna, Cabin vent(s), Recording tachometer, Oil pressure gauge, Battery ,

Oil temp . gauge, Ammeter, Starter (elec .), Exhaust silencer(s) .

SPORT-AV/AT/ON /NC.401 HOLMES BL ✓O. W00STER. OH/0 44651 12167 262-830 1

MOTORGLIDING

Elena Klein, Editor

Vol . 3, No . 5

Published by The Soaring Society of America, Inc .

May 1973

Contents Page

BIRDWATCHER 2

HERE'S HENDERSON 2

MOTORGLIDERS, THE FAA, AND US ,By B . S . Smith 3

FLYING THE MOTORGLIDER 'MERE,By Tasso Proppe 7

PHOTO-ESSAY, by George Uveges 8

SOARING ASSOCIATION OF CANADATECHNICAL COMMITTEE 1 2

POWERED BLANIK 13

LETTERS TO THE EDITOR 15

Cover : Bennett Rogers, in his AS-K 14, by George Uvege s

Material for MOTORGLIDING should be mailed to Elena Klein, 326 Elwood Street, Red-wood City, Calif . 94062 . Subscription to MOTORGLIDING is $5 .00 ($6 .00 outside ofU .S .) for 12 issues, beginning with the current issue . Subscriptions and adver-tising material should be submitted to the Soaring Society of America, P .O . Box66071, Los Angeles, California 90066 . Make all checks payable to The Soarin gSociety of America, Inc .Back issues are available at $0 .50 each . All of 1971 are available except fo rJuly, September, and December ; only March and May of 1972 are available . (Noissues were published between May, 1972, and January, 1973 .) All of 1973 are .available .

ADVERTISING RATES, CONDITIONS, AND SIZES

Display ads : $10 for 4 page ; $15 for ½ page and $25 for full page . Prices arefor full-size, photo-ready copy . Extra charges for make-up, $3 .00 to $5 .00 ; re-ductions, $2 .00 ; and photos, $2 .50 . Sizes : 4-page, 3-3/8 x 4-5/8 ; ½-page, 7 x4-5/8, or 3-3/8 x 9-1/2 ; full page, 7 x 9-1/2 . Classified ads : 50¢ per lin e(30 characters) or portion thereof .

Circulation of the April 1973 issue was 1070 .

1

Five issues of MOTORGLIDING alreadyin 1973! You should be getting this Mayissue in June and who knows? Maybe th eJune issue will be in the mail before July !One of the frustrations of being so farbehind schedule is that our Letters columnis never quite current . I'm including, forinstance, a letter dated September 197 2from Dr . Tawse because I think there i sinformation in it that some of you may belooking for .. Dr. Tawse wrote very recentlyabout the symposium at Elmira in May butour Publications Director, B . S . Smith ,had already written a long report on th esame subject .

We are reprinting an article from th eCanadian FREE FLIGHT of November-December1972 because it shows how the Soaring Asso -ciation of Canada and their MINISTRY O FTRANSPORT solved the problems which wer ediscussed at Elmira .

We thought Tasso Proppe had pretty wel lexhausted the subject of crows in the MarchMOTORGLIDING but no-he has written thistime on flying the Crow and we think you'l lbe as interested as we were. George Uveges 'pictures cover aZZ the angles !

Now how do you like my picture? DickHenderson did it . It's a good likenes sexcept for the eyes . And it sort of goeswith my self-image . Dick's column ought t ogenerate some communication . I'm not goingto edit it (or censor it) . He'll have totake the responsibility for it himself . Ithink it will be more interesting that wayand more likely to evoke a response fromAngry Readers . How about a column heading ,Dick?

POWERED BLANIK (FREE FLIGHT, June-July 1972) is an example of the Germanmaterial we would like to provide for ourreaders . There are also Polish and Yugo-slavian publications with what look likevery interesting articles and pictures .Is there one of our readers who would liketo translate them for us?

HERE'S HENDERSON

How about flying wings as motorgliders ,SLS? The configuration lends itself well tothe economic use of materials - Can comeapart at the most strategic points to mak eassembly/disassembly, transportation an dstorage a one man operation . Read Jim Mar-ske's book on flying wing experiments - In -teresting and inspirational * When MOTORGLID-

ING was first published an SLS design contes twas proposed - Sort of fell by the waysideduring MG's 7 month forced vacation . Howabout doing all we can to renew interest ,that homebuilder plans will eventually b eavailable - At the moment the DUSTER isthe only homebuilt sailplane kit availabl ethat's stressed for engine installation -What about engine kits, Mr . Thor? - Theengine selected, says Mr . Thor, is theJLO 30 HP direct drive - See Aerosport' sRAIL * It would be interesting to see somedesign studies/ideas on all phases of pro-posed Motorgliders/Self Launched Sailplanes/Ultralight Airplanes to MOTORGLIDING forairing, discussion and comments . Thatought to open a Pandora's Box * For pos-sible consideration for SLS this interest-ing information from Banks-Maxwell, buildersof airdrives and propellers for airboats -A 15 HP 1 cylinder 2 cycle direct driv eJLO with a 30x12 propeller develops 7 0pounds thrust - A 23 HP 1 cylinder JLOwith a 48x24 prop develops 200 pound sthrust - Banks-Maxwell claims the 45 HPJLO is equivalent to the 40 HP VW * Acouple of related articles, "The Case ForHomebuilding" by Stan Hall in April SOARINGand "Let's Take a Fresh Look at Ultra Ligh tAirplanes" by Al Backstrom in April Sport

Aviation . Both are the kind of suppor tneeded to really get us airborne * Goodnews and bad news, good news first - Kiek-haefer has developed three Aero engines o f40, 50, and 60 HP, with a 2 :1 reductiongear box - Price is about $1 .00 per c .c .or $430, $520 and $570 in ready to go form -All three weigh 72 pounds without gear box -Box weighs 15 pounds - May be competitionfor VW engines when available - Now th ebad news, availability is estimated at 1 2to 18 months . . .See you next month ,

Dick Henderson

2

MOTORGLIDERS, THE FAA, AND U S(or Where do we Stand on Certification? )

by B . S . Smith

A Spring Soaring Weekend at Elmira,New York on May 11, 12 and 13, 1973 wassponsored by the Soaring Society of America ,Harris Hill Soaring Corporation and theNational Soaring Museum. The primary pro-gram related to National Soaring Museumdirection, plans and activities ; it washighly entertaining. Of particular inter-est to MOTORGLIDING readers was an adjunctmeeting with Federal Aviation Administra-tion representatives on self-launchin gsailplanes which was attended by about 3 5persons including this reporter . We areindebted to Paul and Ernie Schweizer (an dno doubt others to whom I can't give credi tby name) for arranging this opportunity t ohear directly from those in FAA who areinvolved in the rule-making process .

The purpose of this report is t ofurther promulgate the intent of the meet-ing ; i .e ., to let interested persons hea rfrom key FAA personnel on the status o fAirworthiness Requirements and OperatingRules for self-launching or powered sail-planes . And vice versa : Input to FAA fromattendees was vigorous during the cours eof the discussion periods and was furtherencouraged by FAA requesting to hear fromall concerned .

The meeting was chaired by Erni eSchweizer . Representing FAA were Net sShapter, Chief, Airframe Branch, Fligh tStandards Service ; Doug Benefield, Tes tPilot, Flight Test Branch Engineering an dMaintenance, Flight Standards Service ( aLt . Col . in the USAF on a 5-year assignmen tto FAA with about 15 hours pilot time onthe Concorde--how's that for a Motorglider) ;Bob Auburn, Chief, Propulsion Branch ,Flight Standards Service and Russ Maynard ,Operations Specialist, General AviationOperations Branch, Flight Standards Service .Mr . Shapter and Mr . Auburn have considerablebackground and experience as personal par -ticipants in soaring activities . We areindeed pleased that these four gentleme nparticipated .

As further background information tohelp explain what has been taking place, yo ushould know of an early 1972 working meetingjointly held by FAA personnel Shapter ,Auburn and others with Floyd Sweet, SSA

Washington D .C . representative ; Harry Perl ,SSA Powered Sailplane Committee Chairman ;Dick Schreder, SSA Airworthiness and Cer-tification Committee Chairman; SSA DirectorHarry Higgins, an Engineer with Boein gAircraft Co ., and SSA Member Ernie Schweizerof Schweizer Aircraft Co . SSA recommenda-tions were made to the FAA on the matter ofcriteria to be used in developing rule-making to establish a new category, namelypowered sailplanes . There is a lot morethat can be said better by others on thebackground for some of the thinking thathas gone into developing the SSA "position" .Maybe we can persuade them to write for afuture issue of MOTORGLIDING on the prag-matic considerations involved that wil lnecessarily keep powered sailplanes fro mbeing as wide-open a category as one migh tlike .

Well, to finally get into the meatof this Elmira meeting . It should be under-stood that these points to follow are not

settled but were merely being presented byFAA as a common ground from which a Noticeof Proposed Rule Making (NPRM) will b edeveloped . This represents the presen tthinking of FAA and is subject to possiblyconsiderable modification, both "good" and"bad", depending upon one's viewpoint .

The first obvious point to be made i nrelating the history of this matter on thepart of FAA was the need to develop areasonable and practical Self-Launchin gSailplane Category . (Already the meetin gwas treading on toes . Some of the audiencethought the terminology should be "auxiliarypowered") . A proposed standard was drafte din June of 1968 . Review of foreign govern -ment regulations was made in January 1969 .There was an industry review in May 1969 .A year later, May 1970, changes to th epowered criteria were made by FAA . Powerloading of 30 lb/hp, an L/D of 20/1 with aminimum sink of 3 ft/sec and a maximum o f45 minutes of fuel represented thei rthoughts at that time . More industrycoordination took place in December 197 0and then came the SSA industry meetin greview instigated and hosted by Floyd Swee tas referred to above in May 1972 . Includedin the recommendations then by SSA wer eminimum L/D of 20/1, minimum sink of 5 ft/sec, 300 ft/min minimum climb rate and drop -ping of power loading and climb angle a sunnecessary and redundant with the othe rcriteria. Single-ignition was recommended .

3

A proposal was then sent to the FAA regula-tory staff for review .

Further considerations were that tw obasic types of motorgliders were possible-self launching and non-self launching . Th elatter probably should meet all the require -ments deemed necessary for the former excep ttakeoff criteria, with useable fuel not t oexceed 30 min . flight at continuous powe rand the engine limited to operations othe rthan takeoff for flight 1500 ft or mor eabove ground .

Further explanation of the FAA positionwas that some additional requirements formotorgliders would be a need to qualify a sa sailplane (such as 4 ft/sec minimum sink) .Also, if an engine fails on takeoff, i tshould have the capability of a safe on -airport landing-this means field lengt hand altitude determination . Criteria forthis might be a takeoff speed greater tha nor equal to l .1Vs with a rate of climbgreater than or equal to 300 ft/min at th e1 .1Vs (or higher-as selected for the demon-stration) . A safe abort would be require dto be made by demonstrating a takeoff an dclimb to a critical abort height greate rthan or equal to 50 feet, failing the engineand either landing straight ahead or per-forming a 180° turn and landing . A few newflight items, for such as power-on stal land trim changes might be required and the nall the above incorporated into the fligh tmanual including the takeoff data and maxi -mum takeoff altitude certification .

At this point more audience discussionoccurred on nomenclature. What are we talk-ing about? Powered sailplanes? Auxiliar ypowered sailplanes? Or self-launching sail -planes with the additional desire expressedfrom the audience to closely adhere t oInternational/OSTIV requirements if pos -sible?

Basic FAA philosophy in their proposa lwas represented as considering that th eprimary usage to be considered was a soar-ing sport device with power for launch an dinitial climb . Safe recovery and landin gshould be possible if power fails at anytime . Simple low-cost engines with minimumrequirements are desired . Prevention o fhazard to aircraft and personnel resultingfrom engine failure must be provided. Con-sideration of engine failure as similar t orope/wire break was briefly touched upo nwith some favor .

At this time, they have no on-going

proposals for rule-making concerning ratingrequirements . It was pointed out that Wash -ington FAA presently considers airplanecertification necessary for both ship andpilot but that field FAA personnel hav egiven authorization in writing to fly motor -gliders using only glider pilot certifica -tion . FAA is open to more suggestions onthis and asked several of the audienc epresent whether they thought power instruc-tion should be required . (My personal viewis that it's more important to have a soar-ing-trained pilot than a power-trainedpilot if it's to be a soaring craft .) Otherspainted out that minimum check-out for en -gine operation was simpler than the forma-tion flying required in aero-towing. Pilotphysical requirements are also long fromresolution--but the possibility exists thatglider medical certification procedure scould be adopted for powered sailplanes .

Finally, the most encouraging state -ment was that it was hoped a Notice of Pro-posed Rule Making would be released beforethis year is out which would propose apowered sailplane category . Inasmuch asbureaucracy works in strange ways and thereare many pressures from voices numberin gmore than ours, one shouldn't expect to omuch . Mr. Shapter, when I told him I wouldwrite this up, wanted to be very sure every -one understood that none of these proposal sare rules (or even settled to be offered asrules) but still in the talking stage .

Some readers may remember the multi -year battle to get a glider cloud-flyin grating (was it seven years?) only to havethe NPRM on that little goody withdrawnwithout action after industry comment .There's a lot of other industry around t ocomment on this powered sailplane cate-gory with what might be a highly unfavor -able slant . But we've got to keep pluggingaway and SSA's official position is to d oall it can to back what is considered mos treasonable, desireable and necessary to thefuture to soaring activity . The FAA atthe meeting recognize that we need all th ehelp we can get, and so do they need help .Support of the need for powered sailplane sfrom higher-ups in FAA (Mr . Baker is thehead FAA General Aviation man) and in Wash -ington D.C. from such as your elected Legis -lators seems highly desireable .

The following is a summary of compar -ative proposals/requirements (underliningdenotes subject matter) :

4

Present FAAPowered Sailplan eproposal thinking

FAR 23 .Airworthines sStandards :Airplanes

FAA HANDBOOK GUIDE OSTI VRecommendation s

Engine installa-tion would notcrease any hazardwith failure atany time

Type Certificat eEngine per Part33 or new Partfor PoweredSailplanes

Type Certificat ePropeller per Part35 . Prop failureat any time wouldcreate no hazard

Ensure safeoperations

Type Certificat eper Part 33 (Air -worthiness Stan-dards : Engines )

Type Certificat eper Part 35 (Air-worthiness Stan-dards : Propellers)

Same

Same

No Type Certifi-

Type Certificat ecate ; Detonation

glider ; engine 4 5Test 50 hr . Endur- hr . Endurance tes tance Single-ignition

No T .C .

No T .C .2 hr . at T .O . rpm No hazard

Fuel Tank Max .

At least ½ hr . atuseable capabity

max . cont . thrus tfor T .O . and climbto 4000 '

Exhaust system per Sam eFAR 23

Power plant

SameFire Protection118 .3 lines $

fittings119 .1 firewal l119 .3 cowling(All from Part 23)

Design features

No similarnone that might

requirementcause hazard dueto failure ormalfunction

Fire Protection

Part 33 .1 7minimize possiblity Sameline protection

Turbine Engine

Part 33 .19 andblade containment

33 .2 7and rotor suita-

Samebility

5 gal . max .

No limit

Same

Same

None

None

Establish tha tengine and acces -sories are satis-factory

None

Non e

None

None None

5

Present FAAPowered Sailplan eproposal thinkin g

Vibration Operat ethroughout rang ewithout excessivestresses

Vibration sam eas Part 33 .4 3

* None

Calibration tes teither before o rafter enduranc etest

Detonation nonethroughout oper -ating range

Endurance tes t43 .75 hours

FAR 23 FAA HANDBOOK GUIDE OSTIVAirworthiness RecommendationsStandards :Airplanes

Part 33 .33 None None

Part 33 .43 None Non e

Part 33 .37 None Establish tha tdual ignition single ignition is

reliable

Part 33 .45 Same as Same as FAArequires prior Part 33 proposalto endurancetest

Part 33 .47 Same None

Part 33 .49 50 hours Same as FAA150 hours proposal

* It was stated that there was possibly an internal FAA problem in gaining accep -tance for a single-ignition proposal .

Any errors of omission or commissionin the above material are not the fault o fany but the lack of this reporter's exper -tise in getting all the data as presented .Pertinent and helpful suggestions and view-points on this subject from readers toHarry Perl and Dick Schreder will be appre-

ciated. Support of the proposal when an dif finally issued by FAA will of course b enecessary but it's not too early to letothers "higher-up" know of the need fora powered sailplane category as suggeste dearlier above .

NEWS NOTE : Richard Bach (JonathanLivingston Seagull) visited SSA offic eOctober 16, 1972 . Has a "Snow" (rebuilt )Fournier RF-4D . Thinks motorgliding has avery bright future in the U .S . as soon assomeone ATC's one .

A letter from Dieter Scheiba, o fBrussels, printed in July, 1972, Air Pro-gress, mentioned a German-built Doppelraabtraining glider fitted with four lawn -mower engines . This aircraft had been

observed at an airshow about seven yearsago in Belgium. Scheiba said it made aterrifying noise . -DPM

In the July 23, 1972, SkrzydZataPolska, there was a photograph of a mode lof the new Polish SZD-45 motorglider . Itwas described as a two-place side-by-sid emotorglider with a 45-HP VW-Stamo engine ,and a fixed-pitch pusher prop . The mode lwas displayed at the 1972 Internationa lAviation and Astronautical Show, at Hanover ,West Germany.-DPM

6

FLYING THE MOTORGLIDER KRA.EHE

By Tasso Proppe

Motorgliding in the U .S .A. is stil lin its infancy, and it will remain under -developed and somewhat crippled as lon gas the FAA refuses to recognize it as acategory of its own . It is well under wayin Europe, and it turns out that its oper -ating objectives range from practice soar -ing and training on homebuilt plywood-and -fabric ships to reaching the waves in hig hperformance fiberglass machines with asso -ciated price ranges from about $7000 t otwice that amount and more .

News media coverage generally dealswith the sensational and the extravagant ;therefore, little is known about the util -ity workhorses that accumulate flying hoursfor fun and practice rather than wait fo rrecord flights . They fly at weather condi-tions where the expensive ships stay hom ebecause it's not worth the trouble to pul lthem out .

The Kraehe is one of those lesserknown designs that emerged at the beginningof the European Motorgliding movement . Itsdesign objectives :

Low cost .To be built in home shops with

limited toolingUsing materials with simple tech -

nology .Sturdy, to be able to take begin-

ners' punishment .Easy to maintain and to repair .Easy to handle and to transport .To fly, perform, and feel like a

glider, slow, small turningradius to soar in narrow ther -mals ; and the seat up front- -not under or over the sing .

These objectives force a compromis etowards moderate performance, of course ;but here is where the motor comes in : in-stead of buying high performance with ex -pensive fiberglass wing spans, you augmentyour L/D by adding a little power if andwhen required to stretch your gliding angle .

Motorgliding is referred to as "sel flaunching",--take off on your own power . ,be independent of the tow airplane or th ewinch and their waiting lines . Not quit eas well-known: It searches out lift areasaway from the takeoff airfield, or at alti -tudes which would be too time-consuming to

reach by aerotow .And it can work lift areas without

worrying about drifting beyond the pointof no return ; when the thermals becomeweak, it flies home under power .

However, what I want to stress, i sit can work weak and marginal lifts forfun and practice by running the engin ejust at or under the minimum power require -ment level-I call that "adjustable glidin gangle" .

It is this latter feature that makessoaring a lot more independent from uniqu eweather conditions and allows the non-expert to enjoy trying his wings on week-ends when the record-oriented experts don' tthink it worth while to drag out the glass-and there are a lot of non-experts aroun dwho like to fly (the soaring kind of fly-ing) for the fun of it .

I have to admit that the supreme en-joyment is when you switch the engine off .Minimum power is close to idle, so th eengine runs at a comfortable hum, but that' sstill noise . On the other hand, you stayairborne, and the variometer referenc ebecomes zero rather than your normal rat eof sink . If you hit something, it reads"plus", and you work it for what it has t ooffer.

I have typical examples for this kin dof flying :

Elsinore, August 6 : Noon takeoff ;the thermals were too weak for anybody t ostay up . I had to switch the engine bac kon about seven times . The fellows thatjoined me up there on tow had to give upafter a 10-min . fight . This went on fo r1½ hours until one of the thermals provide dreal lift . From then on it was soarin guntil 15 :30 . The fellow who happened t obe with me at that time stayed up ; theothers on the ground had to wait for theirturn on the tow line . It took about an-other hour until we all congregated up-stairs . Some of the thermals that after-noon were pretty narrow . The Kraehe i s

slow enough to fly the core inside . Inspite of its rather high rate of sink withthe propeller dead, it sometimes outclimbsthe glass ships which have to fight aroundthe fringe of the lift .

Total flight time : 3 hr . 15 min .Total engine time 53 min . ; max . altitudegain from the last engine off : 6000 ft .

Hemet, December 27 : The weather wasn' tmuch of anything, a general overcast . I

7

was primarily interested in testing a dif-ferent carburetor anyway . It turned outthat there was some lift around, not enoughto gain altitude, but with the engine off ,or idling, I could hold my own for a whileuntil whatever was there dissipated .

Total flight time : 1 hr . 30 min .Total engine time 66 min . with about fivere-starts .

Torrey Pines Cliffs, February 4 : Beau-tiful weather--hardly a breeze ("a beauti -ful, Zousy day") . Only the Bowlus mana-ged later to hang on for 15 min . Everybodyelse got a little altitude from the winchand, after two passes, had to turn in .Three guys missed doing that in time an dwent into the nudist beach below . I tookoff in the Kraehe to familiarize mysel fwith the cliffs and simulated soaring b yusing just enough power to stay at th eedge . If there was any wind it was paralle lto the cliffs . So, after a while, I addedpower and climbed to a small cloud furtherinland, switched the engine off and workedthe cloud, gaining a few hundred feet .When I came back to the gliderport, th ewind had picked up a little and turne dwest . I still had to switch the engin eback on, all right, but I could slowl yreduce power to near idle (which on a two -cylinder engine without a flywheel amountsto 2000 rpm and probably 3 to 4 HP delivere dto the prop) . Result : Two flights atone hour each, and ridge soaring at it smost enjoyable : I do not have to maintaina safety margin to be able to turn in befor ethe wind dies down too much . If I getbelow the edge, I add power and pull mysel fup again .

Yes, I can hear the purists lament -ing about contaminating the Art. But Ihave heard the purists before, in the earlythirties, when we started using aero towas a means to find thermals in the flat -lands instead of bungie-launching from themountains ; "What a dirty way of cheating ,having yourself pulled to an easy altitud eby the very power planes that we despis eso much--no Silver "C" achievement shouldbe recognized on this dishonest launchin gmethod . . . "

Well, purists, too, are subject t ochange of mind . . .

Of course, I logged "normal" flights ,too : Running into a thermal at takeoff ,at the end of the runway, at an altitud eat which you certainly would not un-hook

during an aero tow . You just try the liftwith the engine still running, and when youhave it centered, you switch the engin eoff .

Ramona, November 4 : Engine off 5 min .after takeoff at 2600 ft . MSL (1200 ft .above ground) and soaring for 1 hr . 20 min .Cloud base was 5000 ft . MSL--not much ver-tical elbow room to go on . Without theengine available, you would stay clos eto your landing strip and pass up lif tbecause of the traffic .

The Kraehe I fly is an oldtimer . Itwas built by an Austrian father-and-so nteam to type-certificated plans designe dby Fritz Raab who is quite renowned fo rultra-light aircraft design . It has a

(text continued on page 11 )

PHOTO-ESSAY, by George Uvege s

A get-together to acquaint two glide rpilots with a motorglider at the Hemet -Ryan Airport, Hemet, California, on Sat -urday, March 10, 1973 .

Owner : Tasso Proppe ; pilots : Walt Mooneyand Ernie Shattuck .

The motorglider represented here is on eof the original designs in a series o fAustrian designs using this configuration .

1 . Motorglider : Kraehe, N11224, S/N 02 2Engine : Puch 650 TR II 2 cylinder ,

4 cycle, 27 HPSpan : 39 .4 ft .Length : 23 .0 ft .Wing Area : 154 sq . ft .Empty Weight : 525 lb .Payload : 205 lb .

2. One following this rig gets the feel-ing he's behind a three diamon dglider .

3. The Crow is towed behind a VW sedan .

4. Mr . Tasso Proppe, the proud owner .

5. The center section is attached to th efuselage with three spar pins .

6. Walt Mooney overseeing the assembly o fthe horizontal surfaces .

8

pusher prop aft of the fuselage pod thatswings between two broomstick type empen-nage carriers .

The empennage itself is stabilize dby 4 steel-cable guide-wires from the trail-ing edge of the wing . The Kraehe has nolanding gear, only one wheel under thefuselage, like any glider .

The engine is an aircooled two-cyl-inder 4-stroke Austrian Steyr-Puch power-plant from a minicar with about 27 HP at5500 rpm, geared down to 2750 by a 5 V-bel tdrive . It looks like half a slice of aVW . The cooling fan and drive have bee nremoved so that cooling is provided b yslipstream only. No taxiing . The ignitionis still the battery/coil/distributer systemwith a small alternator for battery re-charge . The alternator drive (a flat belt )is a problem child . With the alternato rfailed, ignition can run some 4 hours onbattery only, plus a few engine re-starts .

The engine starts like a well-main-tained automobile engine; you just pushthe starter button . In the air, it is eveneasier . The prop aids windmilling rotation .

The Kraehe handles with ease . Witha little wind, she hops off the groun damazingly fast . The rate of climb is moder -ate, but with its low forward speed, theclimb angle is no different from any otherairplane ; climbing into a wind gradient

7. Ernie Shattuck observed the refuelingoperation by Tasso .

8. Tasso and Ernie go over the checklis tafter assembly . A thorough pre-fligh tinspection is conducted .

9. The power plant is housed in the pod ,behind the pilot .

10. Ground handlers lend a hand to rol lthe motorglider to a favorable takeoffposition .

11. Walt Mooney is assisted in the cockpitand given a final checkout befor eflight by Tasso while Ernie Shattuc klooks on .

12. CLEAR?

13. Burrrrrrrrrrrrrrrrrrrrrrrrr

is sheer fun .To help keeping the wings level durin g

takeoff requires tail-dragger type footwork on the pedals . The propeller blaston the rudder makes it very effective . Anabort at that stage ends in a ground loop .

The propeller is pitched for climband over-revs at flight speed (44 mph) ;I throttle a little immediately after break -ing ground.

The engine tachometer indicates 550 0rpm at take off; minimum power to maintai naltitude is at 3800 rpm . The best airspeedis 70 km/h = 44 mph. Theoretically, minimumsink/best climb should be at 65 km/h, bu tI do not measure any difference . Climbingat 70, the engine gets better cooling andsoaring, the overall control is firmer i nbumpy thermals . Below 65 km/h she becomessoft and mushy, loses plenty altitude butremains controllable in roll and yaw through -out stall .

On climb-out, I use thermals as soonas I'm out of the traffic pattern . If thevario reads a suitable increase over thenormal power climb, I feel free to switchthe engine off entirely . It is difficul tto hang on to a thermal that close to theground ; they are narrow and frazzled--s owhat ; if you lose it on comes the engin eagain, together with a little embarrass-ment for a missed show-off .

There is a lot of concern about th epropeller position . Due to the V-beltdrive, there is no defined compressio nstop . To hide the propeller behind thefuselage vertical edge requires de-clutchingthe V-belts and letting the prop windmillinto that position which, in turn, requiresa mirror to watch what you are doing inthe back and a third hand to hold it . Bythe time you got the prop vertical, youhave lost the thermal . To fly a good circl einside yields a lot more lift than a verti -cal prop--so I only go through this ritualwhen I know somebody is taking pictures .

If you happen to have some decentweekend weather (which California did no thave to offer much of this year), she soar slike an angel . With the engine off, sh eoffers all the fun of real soaring pri -marily because of the small turning radiu syou can fly . You are up there with al lthat fiberglass, wallowing in U .S . Choicelift while they have to grind the hamburge raround it . This changes, when everybody

(continued on page 14 )

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SOARING ASSOCIATION OF CANADATECHNICAL COMMITTEE :

On 18th October, S .A .C . PresidentDave Marsden accompanied Terry Beasley o na visit to M .O .T . in Ottawa . Terry hadsubmitted draft proposals regarding th eaircraft and pilot licencing requirement sfor self launching sailplanes and we wishe dto discuss them in person with M .O .T . Otheritems were also discussed very briefly .

Self Launching Sailplanes :We were very pleased to find that

Ministry of Transport accepted our pro -posals, as presented, (with minor edi -torial changes) . For convenience, thes eare reproduced separately . (See below . )

It is believed that the ease withwhich these were accepted was a resul tof "making haste slowly" . Terry wishesto thank those clubs who replied to th equestionnaire on the subject ; particularlythose who prepared constructive comment swhich were used .

It will be noted that these require -ments are by no means "all-encompassing "For example, they do not mention the manwho wants to install an engine into anexisting glider . This type of thing wa sbriefly discussed with M .O .T . and we believethat such cases can be considered coveredby the existing ultra-light requirements .The modified glider, for example, woul dbe considered an SLS in the Ultra-Ligh tcategory, provided that it met the SL Sdefinition .

Power Licences for Glider Pilots :M .O .T . are receptive to suggestion s

regarding changes in the requirements forfor issue of a power licence to an exper -ienced glider pilot . That are your view son this? Any glider pilot who later too ka power course is invited to advise S .A.C .of his views . How many hours to go solo ?Did his instructor feel that he reallyneeded to fulfill the full requirements ?

Glider Pilot Privileges for Power Pilots :Under the present regulations a PP L

holder can, legally, fly a glider . Shouldhe have to obtain a glider licence by sub -mitting an application with supportingrecommendations from a Glider Instructor ?Are you aware of any accidents or incidents

attributable to a power pilot's gliderinexperience? Is the fact that he holdsa PPL sufficient to ensure that he know senough so as not to try and solo a glide rwithout proper instruction? (From Novem-ber-December 1972 Free Flight . )

S .A .C . PROPOSALS TO M .O .T . ON SELF-LAUNCHING SAILPLANES

1 .0 DEFINITION

To qualify as a SLS the aircraft must meetthe following requirements :(a) Max . takeoff run to clear 15-mete r

obstacle not to exceed 600 meters .(b) Min. rate of climb 300 meters in four

minutes .(c) Max. stall speed 45 knots .(d) Min. (L/D) max. 20 :1 .Note : M .O .T. may introduce a maximum seat -ing (2) or max. payload figure ; neither ofwhich we consider unacceptable .

2 .0 CERTIFICATION

Upon recommendation of S .A.C . an SLS hav -ing a foreign type approval may be recog -nized as an approved type and be eligibl efor an M .O .T . Permit to Fly (Private) .This will be renewable annually using th eCCI procedure .

3 .0 PILOT LICENCING

Approvals will be by endorsement of a glide rpilot licence .

3 .1 Student :Instruction in a dual-controlled SLS maybe taken under the supervision of an in-structor endorsed as required under 'In-structor', item 3 .3 following . No personshall solo an SLS unless he holds a studentglider permit or any higher category permitor licence .

3 .2 Private :An endorsement of a licence for SLS wil lbe issued according to the requirement sof either A, B, or C, following :

(A) Licenced Glider Pilot :A licenced glider pilot, having a minimumof 10 hours as pilot in charge of glider smay apply for an SLS endorsement upon pre -

1 2

sentation of :

(i) A letter of recommendation signe dby an Instructor on SLS (see 3 .3 follow-ing), and

(ii) Evidence of a minimum of five hour sflying time (as pilot in charge) on SLS ,to include a minimum of 10 takeoffs an dlandings and 10 engine air starts .

(B) Licenced Power Pilot :A licenced power pilot may apply for a nSLS endorsement (which will be by endorse -ment of a private glider licence) upon pre-sentation of items (i) and (ii) as in (A )above .

(C) Ab-Initio :A student who has trained ab-initio on anSLS may apply for an SLS endorsement (whichwill be by endorsement of a private glide rlicence) upon presentation of :

(i) A letter of recommendation signe dby an Instructor on SLS (see 3 .3 following) .

(ii) Evidence of a minimum total of 1 5hours flying time as pilot in charge o fgliders, SLS, or powered aircraft .

(iii) Evidence of a minimum of five hour sflying time on SLS, as pilot in charge, t oinclude a minimum of 10 takeoffs and land -ings and 10 air starts .

Note : Item (iii) may be included in item(ii) .Note : Where no two-seater SLS is available ,the required flights (for (A) and (B) only)

may be made in a single-seat SLS, providedthat they are under the direct supervisionof an instructor, endorsed as in 3 .3 fol -lowing, or, where no such instructor i savailable, are under the supervision of alicenced glider pilot holding both an in -structor endorsement and a power licence .

3 .3 Instructor :A licenced pilot holding a glider instructo rendorsement may be endorsed for instructin gan SLS on presentation of a letter of rec -ommendation and showing evidence of a mini -mum of 10 hours flying time on SLS, aspilot in charge, to include 20 takeoffsand landings and 20 air starts . If theapplicant holds a private pilots' licenc e(aeroplanes) these figures may be reduce dby one half .

3 .4 Written :Applicants for endorsements in either th eprivate or instructor category shall writ ethe M .O .T . examinations as required fo rprivate pilots' licence (aeroplanes) . Thisrequirement shall be waived in the cas eof aeroplane private pilot licence holders .

4 .0 AUXILIARY POWERED SAILPLANES

An auxiliary powered sailplane (APS) shal lbe defined as a glider fitted with an auxil -iary propulsion system incapable of meetin gthe takeoff and climb requirements for th eSLS . It shall not be permitted to attemptto take off under its own power and shal lbe considered as a glider for purposes o faircraft and pilot licencing . (From Novem-ber-December 1972 Free Flight. )

The following article has been trans -lated into English by Richard Robinson ofSOSA Gliding Club . It first appeared inHOBBY, a technical magazine published i nWest Germany . Unfortunately the photoswhich accompanied the article, could no tbe reproduced for Free Flight .--Ed . o fFree Flight .

POWERED BLANI K"The Sigmund-Flugtechnik in Mosbach /

Baden, West Germany, has developed thefirst motorglider with two engines . The

aircraft maintains the same excellen tflight characteristics as the "basic Blanik"according to the developer .

The "thing" really flies ; and notbad at that--the world's first motorglide rwith two engines! The designers at th eSigmund-Flugtechnik are excited : "themodified 'Blanik', a high performance sail -plane built at the Czechoslovakian air -craft works in Kunovice, is better thanany single-engine motorglider ; and atDM 40,000, not even that much more expen -sive than a single-engine motorglider" ,

1 3

praises the chief designer, Mr . AlfredVogt of his showpiece .

The maiden flight is completed, bu tthere are still two hurdles to overcome .One is the approval of the Air Ministry ;the other to establish contact with th eCzechoslovakian manufacturer . There i sa market potential of at least 30 modifie daircraft per annum, provided that th eCzechs can deliver .

"It is out of the question to manu -facture the Blanik in Germany ; the finalsale price of DM 100,000 would be prohib -itive . We intend to purchase the machine sin Czechoslovakia and modify them here" ,we are told in Mosbach . The modificationof these sailplanes should commence i n1972, but the chief designer, Mr . Vogtand the owner of the company, Theo Sigmund ,don't want to divulge too much more . Theydo mention, however, that "the marketin gpossibilities for this aircraft are reall ytremendous" .

Flight Test :At the maiden flight of the aircraft ,

everything is rather hectic . With IAS ofalmost 150 km/h or approximately 95 mph ,the motorglider circles over the Odenwaldmountain tops at about 800 m. AGL .

Mr . Vogt, the pilot, reports "tha tthe aircraft 'feels' fine and he will nowtest the gliding characteristics" . Abouta half-hour later, the test pilot land sthe machine smoothly and exclaims happily ,"We have done it ; the aircraft is okay" .

After that, some of the until-thencarefully-guarded secrets are revealed !The Sigmund-Flugtechnik will try their

hand at small-aircraft building and th emodified Blanik will be their first exampl eof ability and "know-how" .

Engine Mounts :They are not just anywhere on th e

wings, but exactly where they aerodynam -ically should be . They are formerly manu-factured by Lloyd, an automobile manufac-turer in Bremen . They are two-cycle engine sof 400 ccm displacement developing 22 hpat 5,500 rpm . They were built, however ,for motor boats and skidoos .

To use them on the Blanik, duo-carbur -etors for three-dimensional aircraft move -ments were added . The exhaust gases di dcause some problems which, according toMr . Vogt, are now solved, however . Th especial exhaust system permits maximumpower output at the best possible nois econtrol .

The range of the aircraft can be in -creased from 500 to 900 km . by removingone seat to make room for a reserve fue ltank .

Flight Characteristics :The modification did not alter the

excellent flight characteristics of th eBlanik . The gross weight is 620 kg o rapproximately 1,370 lb . The glide rati ois between 1 :20 and 22 . We are told tha tit will take a few more months before th eBlaniks are ready to go on the market .The aim is to provide a completely fool -proof aircraft, an aircraft for the enjoy -ment of many pilots . (From June-July 197 2Free Flight. )

. . .KRAEHE (continued from page 11 )

high-tails it to some other place . I haveno penetration. As seen from my cockpit ,they just stay up there and at the nex tthermal stop, I have to work my way fro mthe bottom on up .

That's no way to fly any record dis -tances, of course, but it develops skill -which is something to be proud of, too .

Preparing for landing, I start th eengine and run it a little before I jointhe pattern ; coming down from altitude ,the engine is too cold to be fully avail -

able should you need it to get out of some -body's way (I can afford to be polite) butfor the actual landing, I go in dead stick .With the engine still idling, the shi p

floats too much . For touch-and-go's, I

re-start the engine after touchdown, (mak esure the engine is warm enough to accept

full throttle) .No-wind or crosswind landings are a

little awkward. You lose aileron contro l

before you lose speed; the wing tip dropsand you are in for an out-of-control swing .

That's about it,--needless to say, I

like it .

14

LETTERS TO THE EDITOR

May 27, 197 3Dear Ed :

I attended with Dr . Tawse o fMansfield the Meeting on Self Launch -ing Sailplanes last May 11th on Har-ris Hill . . .I decided to write anappeal to all "interested persons "to write their opposition to the FA Aconcerning one proposed regulationwhich would severely limit the usag eof any auxiliary powered sailplane .

Thus, I would like to ask yo uto publish the attached appeal ; dueto fact that these rules are in pro -cess of being written as a "Notic eof Proposed Rule Making" my appealshould be published as soon as pos-sible. . .

According to MOTORGLIDING thereare some 1,000+ paid subscribers ;if 1/10 of them respond by writin gto FAA some positive action shoul dbe forthcoming .

To identify myself I would lik eto mention that I am a graduate en -gineer by profession, have my ownengineering office, AMTECH SERVICES ,and am for some time engaged in designof the best aux . powered sailplane ,see my articles in MOTORGLIDING, May1971 (p . 9), Jan ./Feb . 1972 (p . 15) .It appears I was the only enginee ractively engaged in the design pre -sent at the above mentioned meeting .

Yours truly ,S .O . JenkoDipl . Ing. ETHR .D . 8Mansfield, Oh .44904

URGENT -- ACT NOW !

As mentioned elsewhere in thi sissue (p . 3,,B .S . Smith) FAA is infinal stages of preparing a Notic eof Proposed Rule Making (NRPM) gov -erning the design, manufacture an duse of Auxiliary Powered Sailplanes

(APS) also known as Self LaunchingSailplanes (SLS) .

While the proposed regulation sas presented and discussed during th emeeting on Harris Hill on May 11 ,1973 appear to be reasonable one spe -cific rule which would limit the fue ltank capacity became the hottes tissue of the meeting .

It appeared, everyone presen topposed it .

The proposed regulation was partof the FAA "Philosophy of Proposals "

(1) Primary UsageSoaring SportPower for launch and ini -

tial climb to 4000 ft .(2) Safe Recovery and Landing

(3) Simple, .Low .Cost Engines

(4) Prevent Hazards.

Thus, in connection with (1) th efuel tank capacity would be severel ycurtailed from the present maxima lallowance of 5 gallons (FAA Basi cGlider Criteria Handbook) . OSTIV hasno limitation on fuel capacity .

The FAA concern to prevent apossible use of an APS as a poweredaircraft for transportation purpose shas its justifications . The situa-tion is similar to trying to preven ta VFR pilot to fly IFR through clouds .One does not need to remove the per-tinent instruments from the airplane ;the VFR and IFR_clearly define th esituation .

Thus, if the present FAA regu -lation, already sufficient, would b efurther implemented to read (additio nunderlined) :

"The requirements of this chap -ter are applicable to gliderswith power for self-launching ,based upon the premise tha tpower is intended to be used for

1 5

take-off, climb and incidental ,intermittent use thereafter inconnection with soaring flight . "

then the usage is clearly defined .Also, the present maximal fue l

tank capacity (5 gallons) should re -main or be replaced by a requiremen tthat

"The fuel tank capacity shal lnot exceed a one hour suppl yat cruising speed engine power . "

This would allow an APS with apiston engine three takeoffs an dclimbs to altitude with a littl ereserve left in the tank . In cas ethe first climb is not followed bya soaring flight another takeoff canbe made with some fuel remaining i nthe tank .

For decades the APS usage con -sisted of takeoff (self-launching )as well as an occasional use of powe rto overfly the sink areas instead o fbeing forced to land . This featureeliminates a retrieval by car o rpower plane . In view of the presentfuel shortage brought on by colossalmismanagement and misuse of natural

resources the inherent capability o fAPS should indeed be welcome and pro -moted .

It may be easier to include NOWthis fuel tank capacity requirementchange than after the issuance of th eNPRM . If you share the above viewwith other concerned APS enthusiast sthen sharpen your arguments, manner sand quill and write to your Friendl yAviation Administration . Addres syour comments to :

J . L . BakerAssociate Administrator for Gen-

eral AviationFederal Aviation Administration800 Independence Avenue S .W .Washington, D .C . 20590

It is important that you presentyour comments and views in a busines smanner . Derogatory, intimidating and"crank" letters have no place and arerightfully rejected .

So, act NOW in order to be abl eto fly your APS in the future !

P .S . Those who contemplate oralready have a rubber band-poweredAPS should have no worries--at leas tfor a while !

April 23, 197 3Dear Ed :

In the February 1973 issue of MOTOR-GLIDING there was a brief reference to aK-8B fitted with two stihl chainsaw enginesobserved at the Burg Feuerstein . Is theresomeone in the U .S . familiar with thi sretrofit or a similar one using chainsawengines . If so, would you please provid ean address in this country or Germany t owrite for details . This also should be o fmajor interest to other readers of MOTOR-GLIDING if the details are available forpublication . This is exactly the type o fretrofit which if practical could provid ea major boost to interest in motorglidin gin this country .

Thank youCarroll B . Butler107 Meigs Dr .Shalimar, Fla. 32579

April 9, 197 3Dear Ed :

I'm very glad to see MOTORGLIDING backin publication again . Thank you for sendingmy back issues . I am very interested intrying to locate information on any jet-powered sailplane . The only one I've beenable to locate so far is the Caproni A-21Jsold through AviA International . If youor any of your readers know of any otherjet-powered sailplane available I woul dappreciate hearing from you . If you haveno immediate information, perhaps you couldrefer me to someone who might?

Thank youM. G . Meacher16-66th Ave . # 5Playa Del Rey, Ca .9029 1

16

September 24, 1972Dear Ed :

It has come to my attention tha tImported Engines, Inc ., 2505 Main St . ,Buffalo, New York, will be stocking part sfor Hirth aircraft engines and those part sthat aren't can be ordered via Telex fromGermany and should be delivered within fiv edays by air freight . They would prefer t owork through their local distributors whe npossible but a call to Mr . Floyd Zaephel at(716) 837-0100 should get immediate results .

Hirth has also established a researchand development center in the Detroit are aand Mr. Fred Anderson at (313) 477-4068 i sin charge of the aircraft motors and seemsquite anxious to help with any problemsarising in their motors . Hirth has sold aconsiderable number of motors to Bede Air -craft and that probably accounts for thei rincreased facilities .

Robert W . Taws e341 Cline AvenueMansfield, Ohio 44907

May 7, 1973Dear Ed :

I have been soaring for approximatel ytwo years out of Chester, South Carolina ,Bermuda High Soaring Club, and on severaloccasions longed for a motorglider-no tonly waiting for a tow, but desiring t oexplore further afield safely .

The purist glider pilots hooted mydesires .

In March, while visiting briefly inEngland, I went down to Biggin Hill Airpor tand spent two afternoons motor gliding withBrian Stevenson, who is the representativ eof Sperber Sportavia in England .

After coming back to the states, Iordered an RF-5B with full-feathering pro pto be delivered in June .

It would be helpful for motorglide rowners if you would print a list of th eowners and their locations, which could b ea prelude to a self-launching sailplan emeet in this country .

Sincerely ,George C . Sell sP .O . Box 3547 C .R.S .Johnson City, Tn .37601

(See September 1971 MOTORGLIDING for anSLS census-DPM . )

April 23, 197 3Dear Ed :

During a business trip to West German yin the fall of 1971 I just happened t oarrive at the Sportavia Putzer Aircraft Co .in time to fly a RF-5B prototype . Need-less to say I was impressed and took de-livery on one in June of 1972 .

Prior to this occasion I had done asubstantial amount of sailplaning and en-joyed it thoroughly . Not being a puris tnor desiring to be one, what had been lef tto be desired has been fulfilled with th eRF-5B .

Two of the ships came over, one fo rCanada, and mine . They came in a containe rto Cleveland and were brought down to Woos -ter, Ohio, where they were assembled underthe critical eye of Bert Buytendyk, distrib -utor for Sportavia-Putzer in the U .S .A. ,Mr . Alphonse Putzer, President of Sportavia -Putzer and Herr Kruber, Chief Mechanic .Bob Bowman, Head Honcho of Wayne Count yAirport at Wooster, Ohio also demonstrate dthat he was quite capable of assembling an dcaring for these aircraft .

Flying was started immediately and aGenave 190 system was installed at Larr yLectronics in Akron, Ohio . This, plus anELT, was the only domestic equipment in -stalled as everything else including aWesterboer Audio/Visual variometer and atwo-stylus barograph was arranged for inGermany .

Since that time I have logged ove r200 hours under power plus 50 without powerand the machine has exceeded publishe dcriteria plus my own expectations . I havehad it to the E .A.A . in Oshkosh, Wisconsinlast year, many local air shows, and mos trecently at the Black Forest Gliderport atColorado Springs, Colorado . It certainlyattracts a lot of attention wherever i tgoes and the questions concerning it arevoluminous, ranging from the ridiculous t othe sublime .

Its greatest advantage for my appli -cation, is utility in flying . However, i thas provided very adequately the other pro -perties that are basically important to m eand those are safety and comfort .

Best of luck in the reincarnation o fMOTORGLIDING .

R . C . Graham1432 Sand Run Rd .Akron, Oh . 44313

17

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