The New Aircraft Kolb Company gets the new name for a good reason: it has new owners, Bruce Chesnut and Brian Blackwood. These successful businessmen from Kentucky bought the company that produced the ultralights they’ve flown for years. Under its third owner, Kolb appears well poised to remain the prolific supplier it has long been. Following Homer Kolb and Dennis Sounder, Chesnut and Blackwood have a hard act to follow, but they seem well suited to the task. After acquiring the prestigious name, the new owners didn’t alter the aircraft or their characteristics. Why mess with success? However, to maintain the Kolb tradition they’ll have to keep innovating. Dennis Souder did very well at this after he took over from Homer and he remains a consultant so the new owners benefit from his long insight to the ultralight community. However, Brian Blackwood created his own personal Mark III. He installed the Rotax 912 (80 horsepower engine), and didn’t skimp on the good stuff.
Kolb Aircraft Mk III + 912
Phone: 606-309-6281London, KY 40741 - USA
|Seating||2-seat, side by side|
|Empty weight||500 pounds|
|Gross weight||1,000 pounds|
|Wing area||160 square feet|
|Wing loading||6.3 pounds per sq ft|
|Length||22 feet 6 inches|
|Height||6 feet 4 inches|
|Fuel Capacity||10 gallons|
|Build time||450-550 hours|
|Standard engine||Rotax 912 4-stroke|
|Power loading||12.3 pounds per hp|
|Cruise speed||75 mph|
|Never exceed speed||100 mph|
|Rate of climb at gross||1,000 fpm|
|Takeoff distance at gross||200 feet|
|Standard Features||Dual controls (shared center throttle, shared center joystick), factory-welded chromoly steel fuselage, in-flight elevator trim (left seat only), folding wing and tail, 3-position flaps, half-span ailerons, steerable tailwheel, adjustable rudder pedals.|
|Options||Rotax 503, 582 or 618 2-cycle engine, dual joysticks, hydraulic disc brakes with heel pedals or drum brake with hand lever, full enclosure, skylight, upholstery, 2- or 3-blade composite prop, ballistic emergency parachute, strobe light, instruments, finished wing ribs, quick-build kit (225-275 hours), partial kits.|
|Construction||Welded 4130 chromoly steel, aluminum, spring steel landing gear, fabric covering.|
Cosmetic appearance, structural integrity, achievement of design goals, effectiveness of aerodynamics, ergonomics.
Pros - Kolb's Mark III design hasn't changed materially since our last report in '91, but that's because the design works well. Successful new business owners appear highly likely to assure the Kolb name lasts a long time. Former Kolb Aircraft (in Pennsylvania) employee John Yates will transfer to Kentucky, assuring continuity for all former customers.
Cons - The Rotax 912 adds considerably to the price tag of the otherwise fairly reasonable Mark III. Traditional Kolb handling suffers noticeably with the addition of the larger powerplant. Lack of changes - except to add more and more system complexity - means the Mark III is becoming somewhat dated.
Subsystems available to pilot such as: Flaps; Fuel sources; Electric start; In-air restart; Brakes; Engine controls; Navigations; Radio; (items covered may be optional).
Pros - Flaps are quite effective, go down deeply in two deployment settings. Flaps are easily deflected even at some speed. Loaded Mark III with 912 power can have additional systems like hydraulic brakes and electric start (though added weight robs some control responsiveness). Trim is handy for left-seat pilot only.
Cons - Flaps control above and behind you means you need to turn and look at setting until you're familiar. Trim cannot be reached at all from right seat (where I flew). Throttle between seats rubs against left-seat occupant's leg making fluid movements tougher (though this is not a problem while cross-country flying).
Instrumentation; Ergonomics of controls; Creature comforts; (items covered may be optional).
Pros - Deluxe seats offered more padding than the standard Mark III sling-style seats. Full enclosures and doors are possible; they were removed for my warm Florida flying. Shoulder belts were installed. Side-by-side seating is optimal for instruction. Entry was very straightforward, especially with doors removed. Dual joysticks were an improvement over standard shared center stick of a standard Mark III.
Cons - Windscreen was only marginally effective with doors removed; very windy cockpit (especially considering strong push of the 912). Tapering nose placed rudder pedals inward, requiring an angled leg posture that was not comfortable. Panel is quite a reach from the steeply raked seats, especially with tight seat belts.
Taxi visibility; Steering; Turn radius; Shock absorption; Stance/Stability; Braking.
Pros - Good ground clearance allows rougher field operations. Excellent visibility for ground operations, especially with doors removed. Full swiveling tailwheel makes for easy ground handling, either taxiing or manually pushing; taxiing further aided by powerful hydraulic brakes. Light rudder pedal forces.
Cons - Typical Kolb cable "slap" (tail control cables routed inside the boom tube) while taxiing is distracting at first. No other negatives.
Qualities; Efficiency; Ease; Comparative values.
Pros - Robust takeoff performance with 81-hp Rotax 912, even while heavily loaded. All Kolb models climb very fast, but the big Rotax really adds energy. Takeoff run is short. Approach visibility is huge. Crosswind capabilities are as excellent as they always are on Kolb designs.
Cons - The Mark III is not a particularly speedy design. Heavily loaded with the big Rotax, a well-equipped aircraft and big occupants, I felt the Mark III lost energy quickly during round-out, though I must confess my experience was limited to a single unworthy landing. I'd advise landing with some power at first, or building and flying lighter. (See article for more on landings.)
Quality and quantity for: Coordination; Authority; Pressures; Response; and Coupling.
Pros - Handling has been legendary on Kolbs since the company started; light responsive controls are one of the plane's main attractions. Well-coordinated system with good harmony. At near gross weight, we were still able to maintain a fairly tight formation with the photo plane. Crosswind operations are limited only by pilot skill; controls are responsive at all speeds. Adverse yaw is less than the full-span aileron SlingShot.
Cons - If you prefer handling with "feedback," a Kolb may not be for you, as it handles quickly and with a very light touch. I believe you can easily get used to it, but the point is you must. Taildraggers present challenges to many pilots; handling during touchdown and round-out may be too "sensitive" for some.
Climb; Glide; Sink; Cruise/stall/max speeds; Endurance; Range; Maneuverability.
Pros - The Rotax 912 guarantees lots of power to lift you and a loaded Mark III aloft, yet with a smoothness 2-strokes cannot deliver. Climb in most Kolbs is awesome, and the Mark III 912 is no different, despite its added weight. Fuel economy is reportedly better than a Rotax 582. Sink rate is very reasonable. Slow-flight qualities are very good.
Cons - Even with 81 horsepower, a Kolb won't be a speed demon. However, the big 4-stroke engine practically assures no one will be outclimbing you. Added power by larger engines means weight increases with some resultant loss of responsiveness. Design can rapidly lose energy in ground effect; try carrying some power at first.
Stall recovery and characteristics; Dampening; Spiral stability; Adverse yaw qualities.
Pros - Stalls were benign and slow thanks to Kolb's hard-working wing design (picture how steeply they can climb). Power-on stall simply turns to mushy burbling flight that is easily recognized. Controls remain quite effective down to stall; very reassuring when doing low-speed approaches. Emergency parachute is always appreciated, as are 3-point (my minimum requirement) seat belts.
Cons - High thrust line pushes the nose over on power addition, the reverse of most certified airplanes (though rather common among ultralights). Stalls in the Mark III 912 got very steep with a nose wallowing at break.
Addresses the questions: "Will a buyer get what he/she expects to buy, and did the designer/builder achieve the chosen goal?"
Pros - The story is the new company ownership; however, they appear to bring adequate funding and capable business skills to the task. Some Kolb employees will make the move to Kentucky, adding continuity. The brand is one of the most successful in the ultralight industry, and the safety record is good. According to founder Homer Kolb and former president Dennis Souder, the new owners are dedicated to maintaining Kolb's excellent reputation. The Mark III is part of a broad family of similar designs.
Cons - Most Kolb designs, including the Mark III, are said to be "build intensive," though a quick-build option can cut the task by close to 50% depending on your level of customization. You'll invest some real money to have a plane like the one test-flown; a Mark III can cost considerably less with a smaller engine. Taildragger designs aren't for everybody; Kolb has no tri-gear options. Side-by-side seating too cozy for some (though usually valued for instruction).
Sometimes I’m amazed that we’ve now got ultralight pilots buying engines that cost more than $10,000. Twenty years ago, Eipper Formance (Quicksilver) sold complete ultralights that cost $3,499. Even in the ’90s, many complete ultralights – engine and all – cost less than the price of a Rotax 912 4-stroke engine on its own. One that meets that description is Kolb Aircraft’s Mark III with a 50-hp Rotax 503 dual carb 2-cycle engine. Nonetheless, the 81-hp Rotax 912 has invaded the realm of what is loosely called “ultralight” flying. Of course, a Rotax 912-powered aircraft simply cannot be used on a single-place Part 103 ultralight. And any 2-place plane with a 912 is less likely to qualify as an ultralight trainer under the training exemption to FAR Part 103; the big engine may push the plane too fast and could make it heavier than 496 pounds (the ultralight trainer empty weight limit).