Subaru Boxer Engines Keep Showing Up In Small Airplanes: Here's Why

William's photo/Shutterstock

Automotive engines successful small, single-prop craft aren't thing new. Aviation enthusiast and mini craft owners person been swapping LS V8s into planes for years. Some of them are DIY projects, while others are done pinch professionally made kits. Automotive engines aren't typically arsenic durable aliases arsenic long-lasting arsenic aviation engines correct retired of nan box, arsenic they're conscionable not designed for nan aforesaid benignant of usage, but they tin beryllium awesome fund options pinch nan correct modifications.

There are respective celebrated car engines for planes, including nan aforementioned Chevy LS, air-cooled Volkswagen engines, and 1 benignant of motor that's gaining rather a spot of popularity: nan Subaru flat-four. Over nan years, respective companies person built mini craft pinch modified Subaru engines already successful them, for illustration Foxcon Aviation and nan Zenith Aircraft Company, and location are much that person created Subaru aero motor packages for retrofitting, for illustration Maxwell Propulsion systems. 

These packages usually travel pinch modifications meant for flight-duty, specified arsenic stronger internals to grip longer high-rpm tally times, arsenic good arsenic simplification cogwheel boxes fitted betwixt nan engine's crank and nan propeller. The second is necessary, since propellers shouldn't rotation astatine nan 7,000 rpm redline of an EJ25. Props don't really rotation past 2,800 rpm, arsenic leaf extremity velocity inches person to nan velocity of sound astatine that point, which drops efficiency.

Bjoern Wylezich/Shutterstock

The bigger mobility is, tough, why do Subaru engines specifically support popping up successful airplanes? Subaru is celebrated for its level aliases "boxer" engines, successful which nan cylinders are horizontally opposed, creating 2 banks of cylinders connected other sides of nan crankshaft. Boxer engines person their advantages and disadvantages, but they're much communal than you mightiness think. Porsche's 718 and 911 models some person horizontally opposed engines, and nan layout is particularly celebrated among craft motor manufacturers. Lycoming and Rotax, for example, build horizontally opposed piston engines for planes.

Boxer engines are celebrated for mini craft partially because their style allows for a much streamlined and aerodynamic nose, minimizing resistance and expanding performance. Additionally, having some cylinder heads are truthful exposed makes for very effective aerial cooling. And if you're going to usage automotive engines, Subaru's boxer engines make a batch of sense.

Another use of boxer engines is smoothness. Since nan pistons are other 1 another, erstwhile they occurrence nan motor people balances itself out, which is 1 of nan reasons Subaru still makes horizontally opposed engines. Smoothness is important successful craft engines, too, and not conscionable for comfort. Obviously, passengers don't want their teeth rattling while leisurely cruising nan skies, and level engines thief support vibrations to a minimum. But smoothness is besides important for longevity, arsenic excess vibration tin accent various parts of nan craft complete clip and origin things to break. So keeping things bully and soft is important, making boxer engines much attractive. 

Allora Empire Art/Shutterstock

So why usage a Subaru motor alternatively of a level 1 from Porsche aliases a much accepted craft motor manufacturer? Cost is simply a large one. Subaru engines are importantly cheaper than Porsche engines, and Porsche engines look for illustration bargains of nan period compared to craft engines. You tin get a rebuilt Subaru EJ25 flat-four for astir $3,500, by a rebuilt Lycoming flat-four tin group you backmost complete $70,000. Admittedly, Rotax engines are cheaper, and tin beryllium recovered successful nan $20,000 range, but that's still acold much costly than a Subaru engine.

Additionally, a Subaru motor tin tally connected premium pump gasoline. The piston engines usually utilized successful ray craft thin to tally connected aviation gasoline (avgas), which tin costs betwixt $6-8 per gallon correct now. While substance ratio varies based connected nan engine, aircraft, propeller, and cogwheel simplification box, craft engines tin beryllium beautiful thirsty. For example, a Cessna 172 Skyhawk, pinch a Lycoming four-cylinder engine, burns 9.5 gallons per hour. Other planes are much efficient, for illustration nan Tecnam P2008, which uses a Rotax motor that drinks 4.5 gallons per hour. It's difficult to find information connected really businesslike Subaru engines are successful aircraft, but since results look to alteration truthful greatly, nan substance costs is what's much important. Premium pump state is considerably cheaper than avgas. 

Subaru engines are besides plentiful, and easy to find parts for, truthful keeping 1 up successful nan aerial will beryllium a spot easier for nan hobbyist aviator aliases experimental craft owner. So if you're looking into either buying aliases building a mini aircraft, nan correct motor for you mightiness conscionable beryllium related to nan 1 that powers your neighbor's Outback.