What Our Members Are Building
Sonny Furmanís Spacewalker II
By Sonny Furman, EAA 1037168, for Experimenter
Working just from plans, Sonny Furman has been building his Spacewalker II for less than 1.5 years as of this issue. He’s not certain if there are any other Spacewalkers powered with the Corvair engine, but since most have utilized the 65-hp Continental, on up to the O-200, it would seem logical that the Corvair should power his aircraft nicely with an expected cruise of 95 to 110 mph.
Upon my retirement from the U.S. Air Force and a long flying career, it certainly appeared reasonable that I would have much more time for recreational flying, but with newfound work and family responsibilities, that all but fell by the wayside.
Nearly 15 years later, the flying bug bit again, despite my trepidation about passing a flight physical. Enter the “new” sport pilot rule, and an entirely new playing field opened up for guys like me, especially as my needs were now really more about building a plane with which to get up and bust a few clouds on the way to a pancake breakfast or two.
The Decision Was Made
I began in earnest in selecting a project that was well within my budget, in addition to using materials which lent themselves easily to the shop equipment already on hand. The idea of either folding or removable wings was also quite desirable, as I might just need to trailer or store the plane at home when not in use, not to mention the limited building space in a two-car garage.
Since I was already very familiar with automotive and diesel engines, the concept and affordability of using an automobile conversion piqued my interest, especially having grown up as a motor-head turning wrenches with Keenan Rolls Royce in Philadelphia while in undergrad school.
Most of all, I wanted to build something that embodied the term “airplane,” or at least captured a certain nostalgia, as opposed to the ubiquitous spam cans that proliferated the flightline. My research led me to my final selections; the Spacewalker II and the Corvair engine to power it.
With looks reminiscent of a Golden Age sport plane, the Spacewalker fit the bill with its two-place open cockpits, removable low wings, straightforward tube, rag, and wood construction, and very pleasing lines to boot. And it’s sport pilot eligible.
While most have been powered with a Continental O-200, the Corvair seemed like a logical alternative, producing an equal 100 hp with just about the same weight. Martin Hone has built a truly beautiful example of a Spacewalker powered by a Rotec radial.
Once I secured a set of plans to build the aircraft, I then set about finding a suitable core engine to rebuild and convert for aviation. I eventually located a recently wrecked 1965 Corvair and bought the entire car. Towing it home on a trailer, I noticed my neighbors looking at me as if I were totally nuts.
Of course my wife was equally mortified once she found me up to my elbows in grease, carefully disassembling a near ancient vehicle that to most would seem like a refugee from the scrap heap. Three months later, the junk Corvair engine had morphed into a sweet six-cylinder aircraft powerplant that runs like a sewing machine.
I built the 2700-cc Corvair from a bare block and did all of my own machine and fabrication work, save for sending the heads and crank out for rebuild and purchasing a prop hub. My rear starter setup and alternator drive are of my own design and so far has worked flawlessly after about 1.5 hours runtime.
After careful study of the Spacewalker plans, I found there were a few small areas that could be improved upon without making any changes to the flight characteristics. So I set about welding the all-steel tube fuselage, increasing the cockpit width by two inches while also strengthening the spar carry-through since
I was concerned that the original design had a few weak points that could stand an upgrade. Of course the engine mount needed to be redesigned in order to accommodate the Corvair, but the rest of the plane was fairly straightforward.
The Spacewalker II is essentially a stick-and-rudder airplane, and I really wanted to retain the look and feel of a sport plane as it should be. This was nothing like the C-130s I was used to flying, and I welcomed the opportunity to get back to something much more basic, fun to fly, and easy on the pocketbook that might turn a few heads.
The cockpit was fitted with basic VFR steam gauges, while I installed some nifty lightweight auto racing seats that with their nicely padded covers felt much more comfy and secure for my creaking spine.
The empennage is the usual welded-steel tube construction. The wings are wood, with a spruce box-type I-beam spar with plywood ribs. The arrangement includes a welded-steel internal truss system, all of which is covered with fabric—robust by any standard and stressed to 6g.
The landing gear was also beefed up at critical points while I modified a nice set of used Cessna wheelpants to cover the 8 x 4 Azuza wheels and brakes.
Forming the front cowl proved a bit daunting, and after several foam mockups I was able to fabricate an attractive fiberglass form that flows well with the classic lines while providing seemingly adequate cooling for the Corvair—but we’ll know for sure once she’s flying!
To date, the engine has been test-run and meets all of my expectations. It turns a 64-inch diameter by 38-inch pitch (64x38) wood propeller from Props Inc.
The airplane carries 16 gallons of useable fuel in a racecar fuel cell modified for aircraft use. Carburetion is supplied by way of an AeroConversions AeroCarb mounted (updraft) to a manifold of my own design, as is the dual ignition system.
The Corvair engine offers to the homebuilder much in the way of flexibility and can be fitted to a wide array of experimental aircraft which otherwise might use certified engines in the 100-hp range at twice the price. I’m optimistic that the venerable Corvair will prove up to the task, providing adequate, reliable power and ease of maintenance.
The outer wings are now in their final stage of construction, and I eagerly anticipate taking to the skies in my Corvair-powered retro sky rod.
Having just turned 65, I’m now content to do mostly Sunday flying, with the occasional fly-in to gorge on pancakes, so the Spacewalker seems the ideal aircraft for that venue, And with an open cockpits, the aircraft truly replicates the Golden Age of Aviation; it’s simply a fun bird to own and fly. This hasn’t come without some dedication to the project, and I normally devote a six-hour day to being sequestered in my hovel.
Much thanks to my wife, Kendall, who has willingly supported my insanity, claiming it keeps me out of trouble. The entire project is now approaching 20 months in production. Lucy, our Greyhound, much enjoys keeping me company in the shop and serves as my quality control inspector.
With the Florida weather now a bit cooler and pleasant to work outside, I sometimes push my Spacewalker out of my garage and onto the driveway, which affords me a bit more elbow room to work on the plane. The lawn and pool guys love to stop and chat as well as the occasional neighbor, most very friendly and inquisitive.
Two weeks ago I was visited by a young attorney who introduced himself as the new homeowners association president. He said, “Colonel Furman, I am here to inform you that you are in violation of the local homeowners association, which expressly prohibits boats, pickup trucks, and bicycles from remaining in private driveways.”
“Humm, can you show me anything in the covenants which says anything about airplanes?” I asked.
The man stood there and stammered for a bit, then shook his head. He sheepishly walked away.
Such is the life of old aviators living in cloistered communities.
I’m still having a ball!
Sonny and Kendall are lifelong sailors and have cruised extensively aboard their 48-foot Tayana sailboat. They recently completed a 31-month cruise before moving to Punta Gorda, Florida, where they now live with their greyhound, Lucy.
AAS Spring Garden Technical Institute
Bachelor of Arts from Temple University
U.S. Air Force 1968 to 1993
C-130E pilot, served in Vietnam 1970 to 1971
Former chief of maintenance 374th TAW
Instructor, U.S. Naval Academy 2002 to 2006
Past president, Vietnam Veterans of America Chapter 712
Home of the 'Spacewalker: www.SerenityAviation.com
William Wynne’s Corvair engine website: www.FlyCorvair.com
Clarks Corvair Parts: www.Corvair.com
Aircraft Spruce www.AircraftSpruce.com
Spacewalker Yahoo! Group: http://groups.yahoo.com/group/spacewalker/