Silhouette traced from a photo of the closest sister model, the Beechcraft Duke, by Pedro Aragão · CC BY-SA 3.0
Rocket Engineering · Turboprop
Royal Turbine Duke
An aftermarket turboprop version of the final Beechcraft Duke, the B60, offered since 2006.
One of the quickest, shortest-runway piston-to-turbine twins you can buy, with a 4,000 fpm best climb and jet-fuel simplicity. The trade-offs are a small cabin, limited payload with full tanks, a 12,000 ft cabin up high and a tiny, hard-to-price fleet.
Buy it if
You fly yourself with one to three passengers on 200 to 600 nm trips, want twin turbine power with short-field ability, and love the Duke's looks enough to accept a rare, specialist-supported airplane.
Skip it if
You routinely carry four or more adults with bags, need a toilet, plan nonstop trips beyond about 500 nm with a full cabin, or want an airplane that is easy to insure and resell.
Biggest compromise
Payload and range. With the 260 gallons of jet fuel aboard, only about 740 lb is left for the pilot, passengers and bags, so a full cabin means short legs.
The numbers that matter
What it costs per year
$540K
at 300 hrs · one professional pilot
How far it flies
1,100 nm
350–500 nm with passengers
How fast
290 kt
high-speed cruise
Seats
4
Pilot plus five; four in club seating
Pilots needed
1
Flown by one pilot; no type rating needed because it weighs under 12,500 lb.
Price
What one costs to buy
Typical asking price
$0
Other sites
Priced vs call
with a price / call for price
None were advertised for sale in early October 2026. AVweb reports converted examples bringing as much as $1.3M; piston B60 Dukes ask about $150,000–$290,000.
Price vs its family and alternatives
Scroll to explore · select a jet for details
Cheyenne I / IA (PA-31T1)
$467K–$495K guide
Guide value, not a listed asking price.
See the Cheyenne I / IA (PA-31T1)For sale now
None listed right now
Cost to own
What it costs per year to run
300hours / year
Per year
Per flight hour
Estimate — your operator will quote actual numbers.
Fuel, airframe and propeller maintenance, engine overhaul set-aside and trip fees rise as you fly more. One professional pilot, recurrent training, hangar, insurance and databases and tracking stay the same however much you fly.
Where the money goes
- One professional pilot$145,00027%
- Recurrent training$12,5002%
- Hangar$30,0006%
- Insurance$27,5005%
- Databases and tracking$6,7501%
- Fuel$149,37028%
- Airframe and propeller maintenance$65,00112%
- Engine overhaul set-aside$85,50016%
- Trip fees$18,7503%
Fuel is the biggest single cost at 28% of the total.
The JetGrade
62 out of 100 — Below its class average
Peer group: Piper Cheyenne I / IA, Cessna Conquest I (425), Beechcraft King Air C90A, Mitsubishi MU-2 short body
Seven categories at a glance
- - - 70 = typical— This aircraft
Strongest on airport access, weakest on range & payload.
Grades are editorial opinions about the model, not any specific aircraft. Sponsors and affiliates have no input. Reviewed 2026-10-04.
Where it flies
Sample trips and reach
Typical trips on a map
Nonstop
Depends on weight or weather
Fuel stop likely
Out of reach
1 of 6 sample trips are comfortable nonstops.
Sample flight times
- 1.2 hr
Carlsbad → Las Vegas
205 nm · Short hop; plenty of payload with full seats
- 2.8 hr
Carlsbad → Aspen
625 nm · Payload-limited; nonstop with about three passengers
- 3.6 hr
Santa Ana → San José del Cabo
765 nm · Nonstop possible with two passengers and full fuel
- 4.1 hr
Teterboro → West Palm Beach
900 nm · One stop with four passengers, typically the Carolinas
- 5.6 hr
Dallas → Teterboro
1,190 nm · Two stops with four passengers; one with two
Carlsbad → Teterboro
2,100 nm · Three or more stops with four passengers
Lineage
What came before and after
What changed from the Beechcraft B60 Duke
- Two Pratt & Whitney PT6A turboprops replace the turbocharged Lycoming piston engines.
- Maximum takeoff weight rises from 6,775 lb to 7,050 lb; empty weight drops about 400 lb.
- Fuel capacity grows 28 gallons to about 260 gallons of jet fuel.
- Winglets, vortex generators and tail strakes are required parts of the conversion.
- The instrument panel is replaced, typically with Garmin navigators and displays.
- Four-blade reversing propellers cut takeoff and landing rolls to about 1,000 ft.
Size and cabin
How big it is, inside and out
Outside
Silhouette · scaled to length
Length
Wingspan
Height
Compare
How it stacks up
This aircraft
Royal Turbine Duke
- JetGrade
- 62
- Cost per year
- $540K
- Range
- 1,100 nm
- Speed
- 290 kt
- Seats
- 4
- Pilots
- 1
- Years built
- 2006–now
← Before
Beechcraft B60 Duke
Not yet graded
Alternative
- JetGrade
- 66
- Price
- $467K–$495K guide
- Cost per year
- $510K
- Range
- 1,330 nm
- Speed
- 249 kt
- Seats
- 5
- Cabin length
- 8′ 5″
- Pilots
- 1
- Years built
- 1978–1984
Alternative
- JetGrade
- 67
- Price
- $1.23M
- Cost per year
- $531K
- Range
- 1,240 nm
- Speed
- 262 kt
- Seats
- 5
- Cabin length
- 10′ 7″
- Pilots
- 1
- Years built
- 1980–1986
Alternative
- JetGrade
- 71
- Price
- $1.42M
- Cost per year
- $550K
- Range
- 1,120 nm
- Speed
- 247 kt
- Seats
- 6
- Cabin length
- 12′ 4″
- Pilots
- 1
- Years built
- 1984–1992
- Piper Cheyenne I / IA instead: A factory-built PT6 twin with a roomier cabin and a much larger fleet, so parts, training and resale are easier; slower than the Turbine Duke.
- Cessna Conquest I (425) instead: A factory turboprop twin with more cabin and baggage room and a bigger owner community, at the cost of the Duke's short-field punch.
- Beechcraft King Air C90A instead: Slower, but the default light turboprop twin: bigger cabin, toilet options, deep service network and the most liquid resale market in the class.
Gold marks the best figure in each row.
Owning one
What to know before you buy
Engines & inspections
2 × Pratt & Whitney Canada PT6A-35 (PT6A-21 optional) · 550 shp each
No APUEngine hours until overhaul
- 100-hour inspection · 100 hr
- Engine hot section inspection · 1,800 hr
- Engine overhaul · 3,600 hr
- Annual inspection every 12 months
Factory engine warranties from the conversions have expired; plan an owner set-aside for overhaul and hot section work unless an hourly plan is confirmed.
Known issues
Tiny fleet, specialist support
About 21 conversions exist; conversion parts and know-how come mainly from one small company in Spokane, Washington.
Aging Duke airframes
Airframes date from 1974 to 1983; landing gear, wheels and pressurization valves need close attention.
Wing bolt and tail inspections
A 2001 directive covers lower wing bolts, and a 1989 Beech bulletin requires tail hinge inspections.
Pre-buy checklist
0 of 9 checked
Northwest Turbine and Rocket Engineering in Spokane support the conversion, independent Duke specialists and the Duke Flyers Association help with the airframe, and the PT6A engines have worldwide support.
Review
The full review
Strengths
- Cruises at about 290 knots near 28,000 ft on 64-70 gallons an hour, with up to 4,000 fpm climb.
- Takes off in about 1,000 ft and stops in about 1,000 ft using reversing propellers.
- Two PT6A-35 turboprops with 3,600-hour overhaul intervals replace the Duke's troublesome turbocharged piston engines.
Limitations
- About 740 lb of payload with full fuel; four passengers cut practical range to roughly 500 nm.
- Cabin altitude reaches about 12,000 ft at 28,000 ft, and most have no toilet.
- Only about 21 conversions exist, built on 43-to-52-year-old airframes, so support and resale are specialist territory.
The Royal Turbine Duke is a Beechcraft B60 Duke, the pressurized six-seat piston twin Beech built from 1974 to 1983, with its turbocharged Lycoming engines replaced by two Pratt & Whitney Canada PT6A turboprops. Rocket Engineering of Spokane, Washington, developed the conversion and received FAA approval in May 2006; its sister company Northwest Turbine markets it. Most conversions use the PT6A-35, flat-rated at about 525 to 550 shp per side, with four-blade Hartzell reversing propellers. A cheaper PT6A-21 option was offered. About 21 Dukes have been converted.
Pilot's take
The appeal is obvious from the left seat: two PT6s on a Duke airframe give a climb rate and short-field ability few pressurized twins match, and cruise near 290 knots on about 66 gallons an hour. Minimum control speed rises to 91 knots, 10 knots above the piston Duke, so engine-out training matters. Fuel planning drives every trip; a full cabin means shorter legs. Expect to fly at or below the high 20s with a cabin near 12,000 ft, and to keep the oxygen handy.
Who this is for
An experienced owner-pilot who usually flies alone or with two or three passengers, values speed, climb and short runways over cabin size, and is comfortable owning a rare conversion with a specialist maintenance network.
Ask about this aircraft
Answers come only from our research file on the Royal Turbine Duke (conversion).
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