Plane & Pilot
Tuesday, July 3, 2012

Soloy Cessna 206 Mark II

Transplant a 450 SHP Rolls-Royce turbine onto a stock 206 and, voilá, you have a super Cessna

The Cessna 206 flies behind a nosewheel, and that limits the airplane's operation to relatively smooth, semi-improved strips. They're nevertheless popular machines in the world's outback destinations.

Though the most common applications of turbine upgrades are for enhanced climb and cruise performance, Soloy's goals are slightly different, especially on the 206 and 207 (the latter now long out of production), where utility operation is more the rule than the exception. For the Stationair, the mission is often where you can go and how much you can carry, rather than how quickly you can get there.

Soloy built some 85 of the initial Mark I conversions that utilized the Rolls-Royce 250-C20S turboshaft engine, pumping out 418 shaft hp. That represents nearly a 40% power increase, with the obvious implications.

In October 2008, Soloy received approval for the follow-on Mark II conversion, specifically designed for the 1999, and later, Cessna 206H/T206H. This upgrade uses a Rolls-Royce 250-B17F fitted with Soloy's Turbine-Pac gearbox-drive system. The engine is rated for 450 shaft hp, roughly a 150 hp increase over the original Lycoming IO-540/TIO-540. Dual vacuum pumps, digital engine instruments and a Shadin fuel computer are standard, as is a bleed air heater in place of the standard muff-type system. Electrically deiced propeller and air inlet heater also are standard features of the Mark II conversion.

Soloy has redefined the applications of the 206 to make turbine Stationairs even more attractive for applications such as skydiving, law enforcement, fish and game, pipeline and powerline patrol. To help facilitate those tasks, the Soloy conversion realizes a payload increase of roughly 170 pounds, a function of the lightweight turbine engine (since gross weight remains unchanged at 3,600 pounds). Balancing the CG with a lighter engine demands extending the nose forward, improving the airplane's lines and lengthening the fuselage by at least a foot.

The airplane I flew for this evaluation was what Soloy calls the Sentinel, a dedicated law- enforcement version. The test airplane was fitted with a remotely mounted FLIR (Forward Looking Infra Red) system beneath the left wing, a specially adapted third seat aft of the pilot stations and a large vertical floor-to-ceiling observation window on the left side. The large aft left window can be purchased separately, and has proven extremely popular. Soloy has sold 150 conversions of the tall observation window.

All the modifications have little effect on aircraft control, though the heavy FLIR system halfway out on the wing does demand slight roll trim compensation.

I had flown the Mark I conversion many years ago in Washington, so I was eager to sample the new airplane's talents. Soloy demo pilot Paul Haagland manned the right seat, and we taxied out for a short demo flight in the Los Angeles area.

Predictably, a third more power makes a remarkable difference in performance. If you're leaping out of a short strip, you'll appreciate the strong push when the power goes forward; then, you can watch the VSI do things you've probably never seen on a 206. At light weights, the Soloy Mark II will drive the needle up to 1,500 fpm or more. Better still, if the mission demands high-altitude operation, the Soloy Mark II can vault higher in a similar hurry.

Having extra power is especially welcome on waterbirds, and the new mod will undoubtedly find happiness on Stationair floatplanes and amphibians. Nearly a quarter of the original Soloy Mark I conversions were made to float-equipped Stationairs. Climbing up onto the step with a heavy load can be a struggle with the standard piston engine under even the best of conditions, but it's far safer and more enjoyable with the Rolls-Royce 250 out front.


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