Improving the Breed
Randy Hebron's EJ-22 Subaru-powered Volmer amphibian
By Anthony J. Liberatore, EAA 99484
Many a pilot has been attracted by the allure of the amphibious aircraft. With the amphibian’s ability to make your favorite lake not only a runway but also an adventure, who could resist? But owning and operating an amphib is not all that easy. With the added complexity and maintenance just for starters, ownership is certainly a challenge with a production bird let alone an experimental. However, there is one individual who not only has succeeded within the experimental amateur-built rules (while incorporating a host of other enhancements that have truly improved the breed), but has done so with an automobile conversion. That individual is Randy Hebron.
Randy (EAA 149183) purchased his VJ-22 Sportsman amphibian in damaged condition, after an accident in 1982 destroyed its fuselage forward of the wings (see the 1987 Water Flying Annual). After his completion of the rebuild process, Randy continued to fly N6857 with its Lycoming O-235-C1 mounted in the tractor configuration. This continued for 12 years until one day while airborne, the Lycoming stuck a valve. Fortunately, Randy was flying over a Michigan lake where he proceeded to execute a safe emergency water landing. It was in the initial stages of the engine rebuild that Randy started to give serious consideration to an auto engine conversion, primarily in response to sticker shock while pricing out a set of rings for the aged Lycoming.
A New Engine
Although the Volmer flew fine with the Lycoming in the tractor configuration, Randy wanted to return it back to the original pusher configuration and move the propeller farther away from the cabin. Contemplating and executing such change were not a stretch for him, given his homebuilding background. In fact his name may ring a bell with many KR enthusiasts. In the late ‘70s, Randy and his brother Scott built a highly modified KR-1 that was featured in the August 1980 issue of EAA’s Sport Aviation Magazine.
A vintage photo of Randy’s VW powered KR-1, as featured in the August 1980 issue of Sport Aviation. The article was written and the above photo was shot by then Editor, Jack Cox. Jack is now publishing his own aviation magazine, Sportsman Pilot.
With its updraft cooling, full span flaps, spoilers, and GAPC-1 airfoil, the highly-modified KR-1 was capable of a top speed of 179 MPH on a 1600cc VW engine and a stall speed in the 45 MPH range. While competing in the Lowers-Baker-Falck 500 efficiency and speed competition in 1981, Randy’s highly modified KR-1 was a strong contender. In fact, during the Baker portion of the competition, Randy and his KR-1 took 2nd place.
With that “can do” attitude and experience, Randy chose to replace the Lycoming with a Subaru EJ-22. With its water-cooling, electronic fuel injection, and many other features, it is truly a modern engine. To get the propeller tip speed subsonic for this amphibian’s installation, Randy used one of Don Parham’s RFI Power Systems belted redrives for a pusher-mounted prop.
Randy’s overall execution of the Subaru installation in the Volmer is quite conservative and was an exercise in common sense. His installation predates Steve Lantz’s Robinson V-8 Corvette conversion powered Lake Tahoe Special ( “Tahoe Special,” EAA Sport Aviation, January 2007.) by a number of years and follows the common theme of keeping the engine as stock as possible and the installation as simple as can be.
Simple Is Usually Better
As examples of simplicity, Randy used the stock ignition and electronic fuel injection. A stock Hyundai radiator is used as well, although mounted at an angle for a lower cowling profile. After building some time on the Subaru installation, Randy noticed that his engine oil temperature would occasionally go higher than 220°F, a temperature he was not comfortable with. His solution (mirrored by the Lake Tahoe Special) was to route the engine oil though the automatic transmission cooler that is integral to the radiator, which helped to keep the engine’s oil temperature within the green arc. What I find particularly noteworthy is that two homebuilders independently developed nearly identical solutions to overcome some of the technical and design concerns associated with their auto engine conversions geared towards amphibious use.
Once the Subaru engine installation was completed and test flown, Randy proceeded with a host of modifications to enhance the Volmer’s performance. For starters, different propellers were tried - a Warp Drive and a borrowed Prince - but ultimately Randy, in true homebuilder fashion, carved his own. The current hand-carved propeller is based on tried and proven NACA planform and twist distribution and appears to be robust. Along the way, the propeller was dimpled to complement the Hoerner style prop tips, which were an original feature when it was carved. The results of the dimpling were profound, netting an increase of 100 rpm static and a 1-inch drop in manifold pressure on climb-out.
Attention was further directed toward the Volmer’s aerodynamics by fabricating and installing vortex generators (VG). These were not only added to the traditional VG locations such as the wings and underside of the horizontal stabilizer, but also to the cowling and on the fuselage between the engine’s pylons struts. Another aerodynamic modification that may go unnoticed by folks not familiar with the Volmer is an extended rudder. Randy made this modification for greater rudder authority.
This is not the best shot to illustrate the installation of VGs along the upper surface of the wing, but it still works.
Even those not intimately familiar with the VJ-22 might comment that the rudder is a bit large. Note the line drawing in the accompanying PDF for an example of a “stock” rudder.
The net effect of all these changes is to make this Volmer a winner, and Randy has a number of “first places” to prove it. At the annual Oswego Seaplane Fly-In in Michigan held every June, Randy has been the guy to beat the last few years in the takeoff contest for his horsepower class, which includes Super Cubs on floats! At this competition (lightly loaded) Randy has been timed off the water in eight seconds.
I have been fortunate to be an observer of N6857 and have had the pleasure to be a passenger as well. Although they are not scientific, here are some of my observations. From the shoreline, the engine/propeller installation’s noise is no more obtrusive than a current generation personal watercraft or family boat. After taking off from water or land, the Volmer just seems to levitate and reaches pattern altitude rather quickly. On the water, with two onboard—and using the one-thousand-one, one-thousand-two counting system—once power is fully applied, the aircraft is off the water consistently in the 10-13 second range, as was observed during a recent EAA Chapter “Splash-In,” in which many different passengers occupied the right seat. One might say Randy’s Volmer is “dialed-in” and really gets out of its own way!
Randy and his Volmer are shining examples of EAA and the American can-do spirit, and once again they prove that with hard work and ingenuity you can improve the breed. On top of his volunteering as a technical counselor for his EAA chapter, The Backyard Eagles (Chapter 113, www.EAA113.org), in Canton, Michigan, Randy has graciously shared his Volmer with many others by giving rides in the right seat. The passengers have all shared one thing in common post their flight—a grin from ear to ear, myself included. Especially when their ride originated on the water.
Getting a Set of Plans
The Volmer Club Inc. is a nonprofit, 501(c)3 corporation that is run by a few volunteers. There are no paid employees or officers, and it derives its operating expenses from the sale of information packs and VJ-22 plans sets. (See PDF.) The club is simply trying to preserve this great old amphibian design and see that Volmer Jensen receives his due recognition for the 24 or so experimental aircraft he designed during his career, the VJ-22 being by far the most popular.