"H-I" My GyrocopterBy James W. Higgins, EAA 7692

Yes, I have built and flown a gyro-copter, which I consider no great

accomplishment as many homebuild-ers have successfully built and flownthem long before and since I builtmine. From the beginning this projectpresented a challenge to me, so Iundertook to overcome it "fromscratch". I'll have to admit that thisis not the best way to begin aproject, especially on an aircraft ofthis type on which a lot of valuableinformation can be obtained and themany sets of complete prints thatcan be purchased at a nominal cost.Judging from my own experience andfrom that of others that I have talkedwith on this subject, the savings willmore than offset the purchase price,both financially and in the additionalinformation you'll get from them.

My copter is basically the same asa Bensen, but as you can see by thedrawings I made many changes in thedesign of the frame. I used a dif-ferent method for securing it, whichI call the "block and bolt" method.This simplifies removing and replac-ing any structural members of thecraft, allowing easy disassembly.There is no welding except for oneweld on the nose wheel spindle andtwo in the engine mount braces,which are also bolted to the mainstructure. There can be many varia-tions in the design and structure ofthe frame, as well as a choice ofmaterial used. Many things can bemodified to your own desires pro-vided you use good sound judgment

Jim Higgins and his copter

in accordance with airworthy prac-tices. However, if you do not haveA & E experience or have neverworked around aircraft, I stronglyrecommend that you build strictlyaccording to your set of prints.

I'd also like to stress a point, orrather points, which cannot be de-viated from to any great degree with-out running into serious trouble. Ofcourse there is a tolerance to thesepoints which will be called out inyour set of prints and if you keep wellwithin these you should have noproblems. These critical points areblade track, blade alignment and themost important of all, Center ofGravity of the complete craft. Takeit from me, don't experiment or playaround with this CG outside of thegiven tolerances. Nor would it bewise to press your luck outside ofthe blade track and blade alignmenttolerances as either is easy enoughto check and correct before you riskyour neck. It is possible for alignmentand track to change while in flight.One should be aware of how to detectit, and when this occurs, the properprocedure is to set your craft downimmediately and take corrective ac-tion while you are able.

As I said before, I began from"scratch" except for my few yearsof knowledge and experience gainedas an A & E mechanic. I progressedfine up to a point—and that pointwas one washed-out, clobbered-ingyrocopter! My big mistake was thatI had used the "trial and error"method in finding the CG and forrigging the controls. Let me makethis clear—it is not at all safe orsensible to use the "trial and error"method on anything as critical as theCG location in this craft, or anyother craft for that matter. I knewit to be critical and felt sure that Ihad found it correctly, or was withina degree or so of it. I made manytest runs and kept my power to aminimum. I'd jockey the craft offas sently as possible so as to get the"feel", which was very good experi-ence in that way but it didn't provea thing about the CG, as I was under-powered.

I learned later that as the powerand speed is increased it changes thewhole situation. As a matter of fact,in my case it washed out the completecraft and just very nearly washedme out with it. On this particulartrial I had about 20 mph ground

"H-l"

speed and turned into a 25 mphwind. I was literally snatched offthe ground and went upward andbackwards, and came down upsidedown. For a few split seconds I sup-pose I had the largest rotary lawnmower in the world, but it was shortlived. But the pain, the heartache andin; i red pride, and of course the workof rebuilding the craft remained withme for weeks and even months.

Another important lesson I learnedwas how very, very wise it is towear a crash helmet at all timeswhile flying. Just to own one is notenough, as my wife reminded me atthe time. When I washed out mycopter I had left my helmet in thecar until I made a "little run" andbrought the blades up to proper rpm.But things were going so well thatI thought I'd just chance it a littlefurther. In the first place I shouldnot even have thought of making

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Instrument detailSPORT AVIATION 17

Rotor blade

any kind of test run in a 25 mph wind.Even if I did, there would certainlynot be much need for a ground run.A 25 mph wind is ideal for bladetracking, but after my ordeal I de-cided that I would not go out forany test run at any time the windexceeded 18 mph. Also in buildingmy second copter I made certain ofthe correct CG location before I madethe first test night.

During the testing of the first craftI knew that I must have manyproblems, and after I clobbered itin I was definitely sure of it. So be-fore starting on my second one I be-gan corresponding with other build-ers. It was through their help that Iarrived at a safe CG and also cor-rected some of my other minor prob-lems.

The rotor controls on my secondcraft are of the conventional aircrafttype. I feel that this is a "must"

because of the natural reaction ofanyone who has ever flown before.Even if one has never flown an air-craft but builds a gyrocopter, I thinkhe should by all means rig his craftwith conventional type controls. Thisis not at all difficult to accomplishnor do they add much weight to thecraft, but they do add much to thestability and flexibility.

The nose wheel steering on mymachine is of the conventional type.The rudder controls are tied into thenose wheel steering which gives con-ventional control on the ground aswell as in the air. Also the nose wheelis equipped with a conventional typemechanical brake. By moving moreweight forward of the main gear Iobtained more ground braking action.At the same time this keeps the craftfrom falling back on its tail whenyou get out of the seat after aflight. Elongation of the mountingbolt holes can result from the jarthis causes.

The gyrocopter is not exactly aplaything, nor is it a week-end proj-ect. It is a true aircraft all its ownand should be treated as such inall respects. I mean by this that itis not to be just "thrown together"in a matter of a short time. Evenwith a complete set of blueprintsthere is much careful planning todo and many precautions to take.Throughout the construction theproper safety factors must be bornconstantly in mind, as it is after allan aircraft.

As I see it, one need not be anA & E mechanic to build a gyro-copter, but it helps. During the build-ing of the craft it is advisable tocontact A & E mechanics to giveyou a hand as well as provide in-formation and inspection of it. Def-initely contact the FAA at the verybeginning of the project, for they

Control detail

can fill you in on the details ofregistration limitations and restric-tions. I found the FAA a very helpfulorganization for the homebuilder andthey were very cooperative. Theyhave a tremendous job to do andhave performed it well. We shouldcooperate with them to the limit—let's not be labeled as "RotaryRalphs" or "Wing Wobbling Willies"!

I sincerely hope that my storyhas enlightened a few homebuilderswho are about to accept the challengeand undertake the building of a gyro-copter. It can be fun. Very important—I suggest that you get your wifeinterested in the project too, foryou'll need a good helper (sometimeseven four hands aren't enough!). Mywife Rosa played a very importantpart in my project—right now we'reworking on a helicopter.

I also wish to express thanks tothe Fort Worth, Texas Region of FAAfor their kind attention and coopera-tion. And to Capt. Clem Tromblaymy appreciation for the fine "Pic-To-View" illustration of my copterwhich appears with this article.

(Jim Higgins lives at 117 MeadowDrive, Burkburnett, Tex.)

METAL WINGED MINIPLANE

"Contact!" yells Matt Matthews £s an unidentified helperflips the prop on Matt's Miniplane. Moments later thelittle biplane was winging its way over California's costalmountain range to its home base in the below sea levelImperial Valley.

This example of the popular Miniplane design origi-nated by the late Frank Smith is unusual in thatit sports all-metal wings and a modified Cub landinggear. Powered by a 65 hp Continental instead of theusual 100 hp mill, it performs well, cruising at 88 mphand topping 100. The landing gear has no shock ab-sorbers but it has been found that when the 8:00 x 4tires are given a pressure of 15 lbs/in., the landingand taxiing shocks are absorbed satisfactorily. Pre-sently owned by W. G. Matthews of El Centro, Calif.,the ship will fly hands-off . . . a testimony to thebuilder's accurate workmanship and rigging. Matt hasput some shims under the upper engine mount pads togive the propeller a little downthrust, and has installeda chain and sprocket stabilizer adjusting screw froma PT-19 to cure slight tail heaviness. Structure is allmetal except for the turtleback fairing strips which areof wood. Weight empty is 603 Ibs. — Tom Henebry

20 MAY 1960