This month- we continue our discussions with the VLJ manufactures to uncover their philosophies behind their cabin and interior designs. With the majority of the OEMs offering twin-engine aircraft it was interesting to see the emergence of a handful of single-engine turbofan aircraft being offered in today’s modern general aviation environment. After discussion with Diamond Aircraft (D-Jet) and Piper Aircraft (PiperJet)- it became apparent ...
VLJ Interiors (Part Three)
“The Power of One”
This month- we continue our discussions with the VLJ manufactures to uncover their philosophies behind their cabin and interior designs. With the majority of the OEMs offering twin-engine aircraft it was interesting to see the emergence of a handful of single-engine turbofan aircraft being offered in today’s modern general aviation environment.
After discussion with Diamond Aircraft (D-Jet) and Piper Aircraft (PiperJet)- it became apparent that both manufacturers we spoke to are very confident in the Williams engine which is why they selected only one engine for their aircraft. Piper states that its PiperJet “has an astonishing 17:1 glide ratio which results in a no-wind range of more than 100nm and approximately 45 minutes of glide time-” offering plenty of distance and time to select a suitable airport at which to land. With over 3.3 million hours of operation- the Williams FJ44 engine series has a recorded 1.54 In-Flight Shut Downs for each 100-000 hours of operation. Most of these shut downs were in multi-engine aircraft and were precautionary in nature. Engine technology has dramatically changed in the last few years. Many advances including FADEC (Full Authority Digital Engine Control) are now considered standard offerings which greatly reduces the workload for the pilot whilst optimizing the performance of the engine.
Coupled with an auto-throttle system- FADEC allows pilots to concentrate on safely flying the aircraft first and foremost.
Diamond Aircraft: D-JET
We will begin with a look at the D-Jet being offered by Diamond Aircraft. In a nutshell the D-Jet is a $1.38 million (July 2006 dollars) aircraft- with up to five seats. It is designed to move at 315kts- flying at FL250- and offering a range of 1-350nm with full fuel and a 500-pound passenger payload.
The cockpit will incorporate the latest offerings from Garmin’s all-glass 12-inch PFDs (two Primary Flight Displays) and a 15-inch MFD (Multi-Function Display)- utilizing the G1000 system. An available option will be the Garmin Synthetic Vision System. It’ll be powered by one Williams FJ33-4A-19 turbofan engine producing 1-900 pounds of thrust and utilizing FADEC. The aircraft is scheduled to enter into service on schedule for mid 2009.
World Aircraft Sales Magazine caught up with Mark Lee- director for marketing and sales- D-Jet- to discuss the concept of the D-Jet.
“By utilizing our background in building composite aircraft- the D-Jet was designed from the beginning to be an affordable personal jet.” Indeed- explains Lee- Diamond believes that it is developing a jet it felt was “an unmet need in the marketplace.” By building a fully composite aircraft- weight is drastically reduced compared to an aluminum aircraft. Diamond’s resulting design offers a cabin width of 4’9” and a cabin height of 4’6”. “The aircraft is very comfortable- and provides ample baggage space for almost any mission with three baggage areas - one behind the rear seat that is accessible during flight; one in the nose section capable of hauling four sets of golf clubs; and a long- narrow section in the rear behind the bulkhead for skis and other items-” explains Lee.
All design- engineering- manufacturing- completions and deliveries will be from the London- Ontario- Canada facility- and Diamond will provide a type rating course with each D-Jet aircraft to fully train pilots for single-pilot operation of the D-Jet. Diamond has a network of sales and service partners worldwide.
Meantime- Diamond has not yet announced details about its D-Jet service network- though it says that it plans to ensure a support and service network will be in place to support D-Jet customer deliveries.
Piper Aircraft: PiperJet
Piper Aircraft - needing no introduction - has been in the aircraft manufacturing business for over 70 years- and needless to say- has a lot of history. So if Piper Aircraft is serious about bringing a single-engine jet to market- the chances are the company really did its homework on this one. By thinking outside of the box- Piper went with a single engine based on the “Mini-DC10” concept of installing the engine in the vertical tail. This configuration naturally opens up the cabin- since it is not utilizing cabin area for engine usage.
The result is a $2.2 million (2006 dollars) aircraft- with up to seven seats. The aircraft is designed to move at 360 kts- flying at FL350 and with a range of 1-300nm with a full fuel payload of 800 pounds for passengers. The cockpit will include the latest offerings from Garmin’s all-glass PFDs (two Primary Flight Displays) and an MFD (Multi-Function Display). The powerplant is a Williams FJ44-3AP turbofan producing 3-000 pounds of thrust- but de-rated to approximately 2-400 pounds of thrust and also utilizing FADEC.
With a rear mounted engine the aircraft would be sensitive to pitch changes during throttle changes- and here again Piper developed the PATS (Piper Automatic Trim System) to automatically counter throttle changes and keep the aircraft on a level pitch. All of this ensures a smooth flight and greatly reduces the single pilot workload. Entry into service is scheduled for 2011.
Mark Miller- corporate spokesperson for Piper Aircraft Company told World Aircraft Sales Magazine- “We listened to the marketplace which greatly influenced the PiperJet. Piper conducted an extensive survey within the industry and spoke to thousands of customers- FBOs- dealers and pilots- which determined that the single-engine jet was a very feasible option.”
Piper went on to design a complete new airframe- new laminar flow wing and incorporate the newest and latest technologies. Make no mistake - this is not a rehashed Malibu or Meridian but a complete new aircraft designed for single-engine turbofan operations with all the bells and whistles. Of interest is that this aircraft is also one of the few which will offer as an option a complete enclosed lavatory- a welcomed additional for many potential customers. Miller went on to state that “the focus was not on getting to market first- but on getting it right”.
It would appear Piper has succeeded in its aim- with over 200 firm orders plus the fact that first flight occurred on July 30- 2008 flawlessly. With its already established training- dealer and service network- PiperJet customers should be well taken care of.
A Single-Engine Note…
Of note is that personal single-engine turboprop aircraft accounted for 0.5 percent of aircraft manufactured in 1995- rising to almost 50 percent of all turboprops manufactured today. Needless to say the single-engine turbine concept has picked up some momentum in a relatively short amount of time and could well be here to stay. Diamond already has orders for over 400 units of its D-Jet- and Piper- as mentioned above- has orders for a solid 200 aircraft.
Without taking out a calculator it is very easy to justify a single engine when factoring in the costs for fuel- maintenance and - on a one versus two engines basis - weight savings- which all translate to a potentially much more efficient aircraft and a bigger bang for the proverbial buck.
John Brodeur specializes in Completion Management and Interior Design of business aircraft. Mr. Brodeur can be contacted at Tel: +1 647 448 4748 (Cell) or by email at email@example.com