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Quest Kodiak turbo-prop utility aircraft. (John Absolon)
Quest's Big Bear
By John Absolon | 16 April 2013
The turbo-prop Quest KODIAK comes out of Idaho, but John Absolon finds out that with ruggedness and durability, it has more in common with its Alaskan namesake.
Bear sighted on the Darling Downs!
Well not quite, but with a name like a creature native to the Alaskan Kodiak Archipelago, the Kodiak bear (Ursus arctos middendorffi) is an appropriate name to be given to a no-holds barred, workhorse aircraft from Sandpoint, Idaho in the USA. The Quest KODIAK has migrated to Australia and can currently be found near Toowoomba, west of Brisbane.
The Quest KODIAK was designed for the sort of back country flying that the Kodiak bear would feel at home in. It even has bear footprints on the decent-sized rudder pedals to match.
When Australian Flying evaluated the GippsAERO GA8 Airvan, we described it as being like a Toyota Hilux, a flexible and trustworthy workhorse. The KODIAK is all that and more, being more like a big F250 Pick-up with all the carrying capacity to match.
Some may think that this is typical of an American manufacturer– just add more horsepower– but the KODIAK has been well thought out and still exhibits many refinements.
The concept was developed by Tom Hamilton of Glasair fame and Dave Voetmann, a veteran back-country flier: an aircraft that could satisfy the requirements of various mission and humanitarian organisations, an aircraft that could carry a significant load of cargo or passengers into back-country strips.
This type of operation is frequently served by an ever-ageing fleet of piston-powered aircraft like Beavers, single-engined Otters, C185/205/206/207 Stationairs and Helio Couriers. Now, with the ever increasing cost of maintenance and short supply of avgas 100LL, these types are nearing the end of their useful lives.
Using the proven utility aircraft layout of single-engine, strutted high wing and tricycle undercarriage, the KODIAK looks not unlike a Cessna Caravan ... but that's where the similarity ends.
The KODIAK was designed to operate out of short fields with STOL performance coming close to some of the best STOL aircraft in the world and was first certified to full FAR Part 23 in May 2007. It demonstrates this by being able to take-off in less than 1000 feet and then climb out over obstacles at 1300 feet per minute whilst carrying around a tonne of payload.
A walk around
Powered by the ubiquitous Pratt Whitney PT6A-34 turbo-prop engine developing a maximum of 750 shp (700 shp continuous), the KODIAK has a powerplant that is supported readily around the world.
Couple this amount of power with a solidly-designed structure and the KODIAK is a whole lot of aircraft.
One thing that impresses immediately is the high quality of the finish, and that doesn't just mean the paint job. Although the paint scheme is quite eye catching with it's swept up black stripes and solid colour on top of the white undersides, it's the quality of the airframe structure that stands out.
With most internal parts of the structure incorporating double rows of riveting, there is no apparent dimpling or flex on the external surfaces. The finish, apart from rivet heads seen on the outer surface, is smooth and appears quite solid.
The structure might be strong, but there is no extra weight in the design. Aerodynamically the KODIAK has a unique wing design with a gloved, drooped leading edge on the outer wing panels with a pronounced leading edge droop. Couple this with large span fowler flaps that extend aft on substantial tracks to not only increase camber, but also increase wing area for those slow approaches.
The benefits of this gloved leading edge is that the airflow remains attached on the outer panels for longer when approaching the stall, thereby keeping the ailerons effective. This is a significant advantage in aircraft designed for STOL operations.
Another notable feature of the wing is the fences between control surfaces and the wing tips. This is a feature that is used by a number of sailplanes to improve the effectiveness of the surface by covering the gap caused when the surface is deflected. By effectively sealing the gap, it means that all the airflow must pass over the surface thereby improving its effectiveness.
Combined with the gloved and drooped leading edge, the fences make the KODIAK's slow speed aileron effectiveness superior to most other types.
Quest reports that the full flaps stall speed is 60 KIAS. Unfortunately Australian Flying was unable to investigate this during the test flight due to the prevailing cloud base.
Along with STOL, humanitarian and missionary operations usually comes the requirement to operate from rough fields. The KODIAK is suitably equipped for this with large main wheels and brakes, and the ability to option the aircraft with two different sized tyres depending on the type of operation.
The main struts are of steel construction inside a streamlined fairing. The whole assembly is then cushioned by bushes where the struts mount to the underside of the fuselage.
The steerable nose wheel strut is not forgotten either in its ruggedness. The whole assembly has a long stroke and is braced to the fuselage at the rear of the strut. A streamlined fairing covers over the top of the strut to fuselage intersection.
Walking around the rest of the outside of the KODIAK, numerous other design features become obvious.
The rear fuselage underside is angled up sharply to the high-mounted horizontal tailplane and vertical stabiliser. This gives good ground clearance during rotation and in the flare during high sink-rate approaches. Not ideal, but at least you know you won't ding the tail if you over rotate!
This area is also used in the surveillance version of the KODIAK for mounting various sensors or cameras. With slightly extended exhaust stacks, it is out of the direct slipstream of the hot exhaust from the PT6, unlike the Caravan where the hot efflux goes along the underside of the fuselage.
The fin is quite tall standing nearly five metres high. The rudder is large and very powerful. The rudder, elevator and ailerons all have electrically-activated trim tabs.
Most of the surfaces and especially any slots between control surfaces are equipped with small shark-tooth vortex generators to keep the boundary layer attached. These are very obvious along the inboard leading edges of the wing, the top of the flaps and just forward of the elevator hinge on the top surfaces of the tailplane.
All flying surfaces are equipped with static discharge wicks.
Looking around the business end of the KODIAK, the Pratt and Whitney PT6 is housed in a streamlined cowling with the customary exhaust stacks out each side. The low-mounted engine air intake is also fitted with an Inertial Separator System that helps the engine to avoid inhaling any major foreign objects that could damage the compressor, particularly when operating from unsealed surfaces. This system can be turned on or off, and was turned on for the circuit operations on the test flight.
Going inside
The cabin windows seem a little smaller than those of the Caravan or Airvan but seem to be quite adequate from the inside.
The 1.25-metre square main entry door is a horizontal two thirds/one third split-fold design with integral folding steps in the lower section. To open the door from the outside, the upper half is opened upward allowing access to the locking handle to lower the bottom half.
The cables that support the lower stair section can be disconnected if necessary, enabling the door to hang vertically below the floor to allow easy loading of bulky cargo items or a pallet.
Both forward side entry doors have a decent sized external locking handle that wouldn't be out of place on a small jet or even a small airliner. The handle is a very neatly- machined item that lies flush when closed. Nothing light and flimsy here; just solid, rugged handles.
The forward doors also incorporate an pneumatic seal that is inflated by an electric pump when the internal locking handle is moved into the locked position. This would help keep any exhaust fumes out of the cockpit or deter water or ice incursion. The left-side forward entry door window also incorporates a folding direct view window.
Moving inside, the 1.37-metre wide cabin is spacious and can easily accommodate one pilot and nine passengers. It is 1.44 metres in available height and just over 4.8 metres long. All seats are easily removable and come with their own integral seat belt system; there is no requirement to separately disconnect seat harnesses from either upper or lower fuselage walls or floors.
Currently there are two standards of seats that can be selected. The test aircraft was fitted with the optional Timberline interior that features two-tone upholstery and carpeted flooring whereas the basic Tundra finish would stand up to more punishment with a rubber anti-skid floor covering and single-colour lightweight seats.
The test aircraft also featured individual headset outlets at all seats. Overhead each seat were also air outlets and lights. These are located above each seat on the outboard sides at the top of the sidewalls.
Four rails run the full length of the cabin to support the cockpit and cabin seats, as well allowing full adjustment forward and aft. These same rails are used for attaching the removable tie-down points used for securing cargo. There are no fixed positions in the floor unlike some other utility types.
In the driver's seat
When seated in the front of the KODIAK, you can't help but notice that this is one hulk of an aircraft. The seating position is commanding, with good all round visibility even though somewhat obstructed by the long engine cowl of the Pratt up front.
With lowish window sills, the view down the sides is unobstructed. The side windscreen supports are just a little wide and may pose a need to move your head a bit to ensure you are clear of traffic or obstacles.
The main instrument panel is deep and easily accommodates a full three-screen G1000 EFIS system. With two full Primary Flight Displays (PFD) with standard Synthetic Terrain Display in front of each pilot and a single Multi-Function Display (MFD) in the centre of the panel, the KODIAK is more than adequately setup for IFR operations, including synthetic vision and terrain.
In fact, the KODIAK has recently been approved for single-engine turbo prop IFR operations.
Along the lower panel are located the various electrical switches. These are mainly divided up into master-type switches (MASTER SW, AVIONICS MASTER, AUX BUS, Aux Fuel Pump, Ignition and Starter) to the far left and the various systems switches like interior and external lights to the right of the pilot's yoke.
Below the MFD in the centre of the lower panel is an S-Tec 55X Autopilot.
The main throttle quadrant is a beefy-sized set-up with a manual elevator trim wheel on the left side and then the usual power lever, pitch and condition levers on the top. On the rear face of the throttle stand quadrant is the electric flap switch with marked positions of 10o, 20o and 35o. Colour-coded segments alongside show the limit speed for each position, 138 kts, 120 kts and 108 kts respectively.
The quadrant also contains the rocker switches for the rudder and aileron trims.
Located on the roof above each pilot's head are the twin fuel selectors. Once rotated to the ON position they are held there by a small mechanical latch to avoid inadvertent selection off.
The moulded black leather yokes include the customary PTT switch and autopilot disconnect button and are mounted into the panel like most GA aircraft. Pilot comfort is not forgotten either with four good-sized eyeball air outlets at the top and outboard sides of the main panel. Back-up airspeed, attitude indicator and altimeter dial instruments are mounted down the far left side of the main panel.
After looking at all these features, it was now time to explore how well they worked together.
Let's fly this thing
The test flight was done with Grant Smith, Director of Sales and Marketing from Quest Aircraft Australia located at Toowoomba Airport. Grant has an extensive background not only with single-and multi engine turbo prop aircraft, but also with numerous corporate jets.
After selecting the relevant MASTER and AVIONICS MASTER Switches ON and checking that the various engine controls were appropriately positioned, it was time to start.
First I selected the AUX PUMP to ON, and after making sure there were no fault messages on the Garmin PFD, I selected the starter to LO. Grant instructed me that when the engine rpm (Ng) reached 14%, I could open the fuel condition lever to LOW IDLE. The PT6 immediately lit at this time and began to accelerate. When it had reached 52% Ng, I switched the starter back to OFF.
After the Garmin had fully aligned itself and we had checked the surface conditions on the AWIS, we were ready to taxy to Toowoomba's runway 11.
The weather was looking a little overcast and so there was doubt as to whether we would be able to explore the full spectrum of items that I usually look for on these flights. This didn't deter me from flying this great aircraft though.
Taxying the KODIAK was relatively easy with such good visibility, small advances in power was all that was necessary to get the aircraft moving up the slight incline to the runway.
The nosewheel is steered directly from the rudder pedals and the toe brakes had good feel but any progressive speed control was more easily attained by reducing the power lever back to the beta detent where the prop just discs and produces more drag than thrust.
Lining up on the runway, and after having already selected the propeller lever into MAX RPM and the Condition Lever to HIGH IDLE, all I needed to do was advance the power lever for take-off.
Acceleration was swift. For this flight the aircraft had an empty weight of close to 1800 kg and with three of us on board and fuel, it totalled close to 2700 kg. As Toowoomba's runway is not that limiting– although it is 2100 feet above sea level– Grant considered that 10o of flap was all that was necessary for this take-off.
A good amount of rudder is required to keep the big KODIAK straight, thanks to the PT6's 750 horsepower. Before I knew it I was accelerating through 60 knots indicated, and with minimal back pressure I rotated to achieve an initial climb out at 73 until of clear of obstacles and then accelerated to 85 to retract the flap and climbed at 95.
I was initially caught out by the action of the manual trim wheel turning by itself as we retracted the flaps. Grant then explained that the KODIAK is fitted with an automatic trim compensating system that repositions the elevator trim datum to compensate for the particular flap configuration to help lower pilot workload.
This system is disabled on the ground by a speed switch to avoid inadvertently placing the elevator trim position in an unsafe position when the flap position is changed. Should a trim runaway occur, a cut-out switch is located on the left-hand control yoke. Manual operation using the trim wheel is still available. The trim position of all the surfaces is displayed on the Garmin MFD.
With the RPM now reduced to 2000 RPM we climbed towards the cloud base.
Unfortunately the overcast was around 1500 feet AGL, so we were unable to get up high enough to explore the stall characteristics of the aircraft. I did, however, get a chance to explore the slow speed performance and with the flaps set progressively down to 35o, we slowed back to 75-80 KIAS.
Roll reversals from 30o to 30o of bank were normal at 3-4 seconds. Balancing the turn with the powerful rudder was not a problem. Roll reversals to the right were ever so slightly slower and I put this down to the considerable torque effect of the PT6 up front.
Autopilot operation was also looked at and proved to very straight forward. The future inclusion of the GFC700 will make this a very nice piece of kit and I expect it to be as well integrated as other Garmin G1000 GFC700 set-ups that I have seen.
Returning to Toowoomba, we joined the circuit on crosswind at 120 knots and reduced the torque to around 600-800 lbft; the speed started to decay.
Flaps 10o were selected as the downwind leg was commenced, with flaps 20o taken just prior to turning base with a speed of 90 KIAS, and with HIGH RPM selected and flaps 35o on base, speed was reduced to 85 for the final approach.
The power was now more around the 400 lbft torque area, and you could feel the prop discing occasionally and with the occasional slight adjustments into and out of this band, speed control was very easy to maintain. Nothing like a big circular disc brake on the nose to kill any excess speed!
Flaring from this speed produced a little bit of a float and I just felt that with this flap setting and weight, a little slower speed might have made the flare and touchdown a little easier.
The Pilot's Operating Handbook does mention the fact that a short field landing in this configuration should be approached at 76 KIAS and touchdown accomplished with the power lever in IDLE.
After a few touch and go landings using both 20o and 35o flap configurations, I felt I was well and truly comfortable with the KODIAK.
The final full stop landing enabled me to use the beta and even the reverse mode of the prop to slow the landing roll. By retarding the power lever and raising the detent, I was able to select reverse. You can't reverse the aircraft up, but you can use it for slowing the landing roll. We easily made the first taxiway without having to use excessive braking.
During our flight, the KODIAK displayed its capability to cruise comfortably at 178 to 185 KTAS while using around 320 lb/hr fuel flow. This equates very well with its nearest competitor which is slight slower in the cruise at 165 KTAS.
In their advertising Quest quotes the direct cost of operating the Kodiak as $1.39/nm, or $300/hr. These figures are obviously in USD, but with current exchange rate being roughly parity, they are quite good for an aircraft with this much capability.
However, Grant pointed out that CASA has recently approved the Garmin G1000 fit to be a suitable Trend Monitoring System for engine monitoring and as a result the quoted 4000-hour engine TBO has been extended to 5000 hours.
This reduces the figure in my calculations to $0.98/nm or $294/hr. Not bad for an aircraft capable of carrying over a tonne of payload for around three hours endurance, which would equate to roughly 500 nm range using its modern avionics and sophisticated aerodynamics efficiently.
In all I found the KODIAK to be an extremely high-quality finished aircraft with modern system that bring the latest in reliable EFIS systems to utility operations at affordable costs. Grant tells me that the KODIAK pricing starts at around AUD$1.75 million which is very competitive compared to the competition Pilatus, Cessna
and Airvan products.
John Absolon would like to thank Grant Smith and the team at Quest Australia in Toowoomba for their help in preparing this review.
Span 13.7m (45 ft)
Length 10.42m (34.2 ft)
Height 4.66m (15.3 ft)
Wing Area 22.3 sq m (240 sq ft)
Cargo Volume 7.02 cu m (248 cu ft)
Max Ramp Weight 3313 kgs (7,305 lbs)
Max Takeoff Weight 3290 kgs (7,255 lbs)
Empty Weight 1710 kgs (3,770 lbs)
Useful Load 1603 kgs (3,535 lbs)
Fuel Capacity 1211 litres (320 US Gal)
Prop 2.4 m (96 in)
Prop Clearance 0.48 m (19 in)
Stall Speed (clean) 77 KCAS
Stall Speed (Flaps down) 60 KCAS
Rate of Climb (max cont @ SL) 1,371 ft/min
Rate of Climb (10,000 ft) 867 ft/min
Takeoff Ground Roll 934 ft
Braked Roll (w/o reverse) 705 ft
Certified Ceiling 25,000 ft
Max Cruise @ 172 KTAS, @ 12,000 ft is 50 US gph yielding 979 nm.
Max Range Cruise @ 137 KTAS, @ 12,000 ft is 34 US gph yielding 1,113 nm.
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