Airframe Comes in 200 Pounds Under Forecast Weight

One of the more intriguing VLJ projects in the offing, is a quiet effort from the fellow who designed the Maverick Twin-Jet... a project that got some pretty solid buzz before it was taken over and mismanaged into the ground by erstwhile "jetpreneur" Jim McCotter.

The current plans call for the single-engine Sport-Jet to have a maximum speed of 375 kts, a normal cruise of 340 kts and an economy cruise of 310 kts. The SJ's rate of climb is expected to be 2500 fpm, an operational ceiling of 25000', a stall speed of 68 kts and a landing speed of 80 kts. Sport Jet's range w/IFR reserves are 1000 sm, with a T/O distance of 2300' and a landing distance of 1800'.

While the Bob Bornhofen designed Excel-Jet Sport Jet has been (somewhat) out of earshot, there has been no lack of activity in this program.

Conversations with the team putting together the single-engine Sport Jet have told ANN that the project seems to be missing something... like an entire 200 pounds of anticipated airframe weight. After final paint was added on July 15th, the Sport-Jet was precisely weighed, and while, "the target empty weight had been 2,800 pounds, creative design changes were implemented to lower that number to 2,700 and then to 2,600. Judicious use of materials, constant weight watching, and keeping systems simple resulted in the weight savings."

When the completed and painted Sport-Jet went up on the scales, the bird came in at 2,275 pounds (not including an anticipated 100 pounds for the future interior installation) -- some 225 pounds UNDER the reduced target weight. No one at Sport Jet can recall any equivalent development project that came in so underweight.

For the moment, this weight "savings" will be slightly off-set since the first test engine is a T-58, an installation that will add some 40-50 pounds over the future and final Williams FJ33-4A (which can't be delivered for a number of months). Sport Jet says that final pressurization installations will add about 15 pounds more, as well as some 20-50 pounds for de-icing gear.

Bornhofen claims that, "Even after these necessary weights are added, Sport-Jet STILL HAS 140 pounds of margin before reaching the lower empty weight target. This weight can be used for additions caused by FAA certification... which always occurs."

At this time, Bob chooses not to alter the specifications seen on the website, though more useful load has apparently been gained. A decision will be made about final specifications after initial testing and progress made toward certification.

Sport-Jet has a huge cabin, 59 inches wide, and the occupants in the aft seats can reportedly stretch their legs to full length without touching the front seats (unless they're pro basketball players, notes Bornhofen). Actual seat pitch is 28 inches. Entry is through a split door.

The T-58 makes about 950 pounds of thrust while the Williams FJ33 produces 1500. Test flying with a reduced fuel load (80 gallons instead of the standard 200) will assure the plane performs adequately for the initial tests, which they consider adequate to evaluate the necessary flight handling characteristics at slow and cruise speeds.

The 4,800 pounds GW, less the new 2,600 pound empty weight (still allowing for future weight increases for certification), leaves a useful load of 2,200 pounds. With 200 gallons of Jet-A, some 860 pounds of payload remains. That leaves a load of four 200-pound occupants WITH 60 pounds of luggage. With four 'FAA-standard'  175-pound occupants; luggage loads can be increased to 160 pounds or 40 pounds per person. Since Europe has over-flight taxes on aircraft with GW's over 4400lbs, Bornhofen promises that he can set the GW for Europe at 4400' and STILL have 1800' payload.

The current Sport-Jet test article is said to be a 92% conforming vehicle -- mostly due to the absence of the much-anticipated Williams. The test airframe conforms to 98% of the certified version, missing only pressurization and de-icing. In preparation for its taxi and initial flight tests, Excel-Jet's team of "skunk works" developers, lead by designer Bornhofen, is carefully preparing Sport-Jet for the first flight... which could come within days. The following details have now been accomplished:

• Elevator and rudder flight controls operational.
• Landing gear operational -- gear retracts and lowers quickly and all the pressure switches working.
• Avionics operational.
• Flaps installed. Flap sync controller box all checked out.
• Brakes installed and bled.
• Engine has been test run.
• Ailerons are mounted along with control bellcrank.
• Radios operational, transponder and encoder tested and operational.
• Everything that has been installed and tested, has been properly safety wired and inspected.

Bornhofen claims that this small "skunk works" style of development differs from all other VLJ projects. Sport-Jet has been 95%+ developed using his onw funds and outside investment will only come in after first flights have been completed. Bob is particuarly proud that this program has been done "quietly" and without great fanfare -- and also without lots of hype and the obligatory 9and risky) pre-selling of delivery positions. Bornhofen adds that, "No customer has money tied up in the development of Sport-Jet. Our policy has been not to sell any aircraft before the plane was completely assembled and ready for tests. We are looking forward to the aircrafts performance and flight handling characteristics."

FMI: www.sport-jet.com