Evolution trainer power system
Byline
Joe Wagner | [email protected]
SINCE HORIZON HOBBY released its exceptionally innovative Evolution Trainer Power System .46 RC engines, I’ve been curious—and a little skeptical—about its unusual features. Recently I was able to obtain one of those units to test, and I’m no longer skeptical!
The Evolution .46 is supplied with a special 10-inch, three-blade propeller and a sturdy 2¼-inch plastic spinner. Also, the propeller driver that comes on the engine features an attached 1½-ounce steel flywheel.
That, plus the masses of the propeller and spinner (3¼ ounces total), provides plenty of rotational inertia to ensure smooth and reliable idling. The Evolution .46 has the lowest dependable idle rpm of any glow engine I’ve handled.
The Evolution’s user-guide booklet reads, “Every Evolution engine has been test run and adjusted at the factory, and is ready to fly with no adjustments or break-in required.” I found that hard to believe. Yet it turned out to be true.
Idle performance and break-in
One criterion for establishing whether or not a model engine is properly broken in and fully ready for powering a model is its idling performance. In general, after an engine has been run for an hour or so, its reliable idling speed will decrease noticeably. That didn’t happen with the Evolution.
From its first tank of fuel to the sixth, the Evolution’s idling speed remained the same. I could hardly believe it; all the way down to 1,650 rpm—with an immediate no-hesitation increase as soon as I opened the throttle. Every time, too!
The Evolution’s needle-valve adjustment is restricted to just under a single turn. The “factory setting” worked out perfectly for me.
Altitude and carburetor adjustment
My home’s altitude is 470 feet above MSL. For fliers who live at higher elevations such as Denver, Colorado, and Albuquerque, New Mexico, the Evolution’s manual describes how to adjust the carburetor needles to compensate for the density-altitude difference.
Fuel recommendations
Of course, the fuel used can make a difference too. The recommended fuel for the Evolution engine is 10%–15% nitro-content commercial glow fuel as supplied by Cool Power, Omega, Hangar 9 Aero Blend, or Powermaster.
I used 15% Maxy’s Fuel, which has 15% nitro and 22% oil content. The oil is a 50/50 mixture of castor and synthetic. That worked fine for my Evolution.
Propeller characteristics and flying preference
The Evolution’s three-blade molded-plastic propeller has a rather low pitch. The manual claims that it’s not only quieter than the usual two-blade propeller that this size engine customarily spins, but it also provides more consistent flight performance in maneuvers. I’ll go along with that.
Since the 1950s, I’ve preferred to fly my CL Precision Aerobatics models with low-pitch propellers. That way the flight speed doesn’t vary much in climbs and dives and makes for more consistent control effect.
Starting the engine
Now for startup! As I’ve mentioned several times in previous columns, I much prefer starting by hand when I test a new engine. I can learn a lot from the “feel” of hand-flipping. And with a leather glove to protect my fingers, that’s proved to be quite safe. However, I was leery of that three-blade propeller!
Back in the good old days, I suffered many a sharp rap on the knuckles while trying to hand-start spark-ignition engines equipped with three-blade X-Cell propellers, but the Evolution’s three-blade gave me no trouble.
Maybe it was the spinner’s presence, but I had no knuckle-rap problems in any of the two-dozen-plus hand starts I performed on the Evolution .46. It truly is an easy-starting engine!
Minor assembly issues and tightening the prop nut
I admit that I did encounter a few minor difficulties with my Evolution .46. One was a bit of molding flash on the propeller and spinner parts.
As I routinely do with all of my plastic propellers, I scraped and draw-filed the sharp leading edges to smoothly rounded contours and barely removed the sharp burr from the trailing edges. Don’t round model propellers’ trailing edges. That can make them noticeably less efficient—and noisier.
The Evolution’s spinner fits tightly into its backplate, and the slight molding flash on those parts kept them from fitting together. I used a sharp jeweler’s file and stroked sideways (that’s what draw-filing is) to eliminate the problem.
The Evolution instructions call for employing an open-end wrench for tightening the prop nut. I used a die-cast “plus sign” propeller wrench, as I’ve usually done on my model engines. I found out why that’s not a good idea on the Evolution. Although I have a strong grip, I found it impossible to tighten the Evolution’s prop nut hard enough to stop it from loosening.
Following the instructions eliminated that problem. I’d say that at least an 8-inch Crescent wrench is needed to get the Evolution’s prop nut tight. Adding a bit of blue Loctite before installing the nut on the crankshaft might be good insurance too.
Enya engines availability
I received an e-mail from John Ashcraft (Collinsville, Illinois), asking about the availability of Enya model engines in the US. I used to like Enyas a lot and bought several in the 20th century. But the old importer—Model Rectifier Corporation—no longer carries these engines.
I tried an online search without success. Then I replied to John with that dismal information.
However, Bob Hunt, MA’s former editor, found us a US source for Enyas! Randy Smith of Aero Products imports them. The smaller Enyas aren’t on Randy’s list; there are no .049s, .061s, .09s, or diesels. But he does carry .15–.60 two-strokes and a .53 four-stroke.
Solvents for stuck parts
In the February column, I recommended two commercial fluids that I’ve found to be exceptionally helpful in model engine repair and maintenance: Dawn Power Dissolver and Marvel Mystery Oil. However, there’s one tough engine problem that neither of those is much help with: snug-fitting parts that are rusted together or glued with congealed castor oil, such as wrist pins.
The problem is that the solvents I recommended cannot penetrate into the microscopic clearances between stuck parts. The only solvent I know of that could help loosen a stuck-in-place wrist pin from a model engine piston was Hoppe’s No. 9 Solvent. That’s been a gun owner’s standard cleaning fluid for decades.
Hoppe’s does help in model engine work, but it still takes a fair amount of force to separate the pin from the piston. And that risks damage to the parts.
But two readers recently referred me to a series of tests reported in the April 2007 Machinist’s Workshop magazine. In those, the testers measured the “rusted joint releasing ability” of several solvents and lubricants, including WD-40 and Liquid Wrench. Then they compared their performance with a home-brew of half acetone and half automatic transmission fluid.
Liquid Wrench worked twice as well as WD-40—but the ATF-acetone mix was four times as effective as Liquid Wrench! I’ve got to try that stuff now. I hate taking the chance of spoiling a long-out-of-production model engine by hammering on a drift punch to drive a steel wrist pin out of a cast-iron piston.
Dummy radial and inline engines (ParkFlyer Plastics)
On a recent visit to a fellow magazine columnist, Pat Tritle, in Albuquerque, New Mexico, I saw a lovely dummy Kinner five-cylinder engine in the nose of his scale Fleet Trailer biplane. Then I was pleased to learn from Pat that it was made from an inexpensive vacuum-formed set of “halves” that is available from Keith “Sparky” Sparks—doing business as ParkFlyer Plastics—in Fort Worth, Texas.
Sparky’s website has an amazing list of dummy radial and inline aircraft engines. They include Wright Whirlwind-like seven- and nine-cylinder radials in 12-inch diameters that are suitable for 1/4-scale projects; 3½-inch-diameter seven- and nine-cylinder P&W Wasps for 1/2A power; and a 6-inch-diameter, five-cylinder Kinner that caught my eye.
Sparky’s products follow a short-kit form. They include just front and back vacuum-formed engine halves that the builder needs to glue together, paint, and dress up with wood, wires, and aluminum tubing to simulate pushrods, exhaust pipes, and spark-ignition components.
Instructions are available on the ParkFlyer Plastics website. The result is lightweight, reasonably sturdy, and extraordinarily realistic.
MA
Sources
- Aero Products
(678) 407-9376 www.aeroproduct.net
- ParkFlyer Plastics
(817) 233-1215 www.parkflyerplastics.com
- Maxy’s Pro Racing Fuel (Stanley Jackson)
(305) 299-3578 www.maxysfuel.com
Transcribed from original scans by AI. Minor OCR errors may remain.
