Just returned from DiamondFest

("john smith" wrote)
Any word on D-Jet's (Williams FJ33-4) single engine fuel burn at
25,000-ft?

Thinking about changing the design specs on the Mont-jet, again, Paul?


I'm not sure? I NEED fuel burn numbers for the D-Jet!!!!

We're using the same (Dry weight - 300 lbs) Williams engine:

Spectrum 33 (2) ...and 415 kts @ FL450
D-Jet (1) ................and 315 kts @ FL250
MontJet (1) ............and 435 kts @ FL450 (FL510?)

Empty weight:
SP-33 ......3,620 lbs ...and 7,300 lbs MTOW
D-Jet ........2,590 lbs ...and 5,071 lbs MTOW

MontJet ....800 lbs ......and 1,800 lbs MTOW
RV-3 .........750 lbs ......and 1,100 lbs MTOW

MontJet fuel: 100 gallons (approx.) 700 lbs.
3 hrs @ 40 gal + 20 gal + 20 gal (+ 20 gal reserve)

"Again" ...these (flying SP-33 and design-phase MontJet) numbers are a
result of FiberX and some other manufacturing technique, employed by
Spectrum.

SP-33 ("single piece") Wing .........305 lbs. Tip to tip.
SP-33 Fuselage .............................309 lbs.

MontJet ("single piece") Wing .........90 lbs. Tip to tip.
MonJet (single seat) Fuselage ........60 lbs.
Williams Engine ..............................300 lbs.
Everything else ................................350 lbs.
Total Empty Weight .........................800 lbs.

http://www.ainonline.com/Issues/12_05/12_05_spectrum_1.htm
Some manufacturing info found here.

But first, I need to "un-help" the Spectrum 33 folks. (You know, those good
people in Utah with an actual flying prototype!)

My numbers were ALL #%^&'d UP!
Let's get this right! (Fixes inserted below)

Jet-A = 6.84 lbs/gal (That's the number I'm using, now). I was using 7.0
lbs/gal.

http://www.spectrum.aero/downloads/competitive_analysis.pdf
Competitive analysis Spectrum 33 vs. other Jets.

2 engines and... "4 passengers, NBAA IFR Reserves"

[300 nm]
617 lbs ...is 90.2 gal ....0+53 (53 min) = 102 gph
(51 gph per side)

[600 nm]
688 lbs. is 100.6 gal ...1+41 (101 min) = 60 gph
(30 gph per side)

[1000 nm]
1,096 lbs. is 160.2 gal ....2+50 (170 min) = 56.4 gph
(28 gph per side)

[1,600 nm]
1,647 lbs. is 240.8 gal ....4+35 (275 min) = 52.8 gph
(26 gph per side)

I wonder if Diamond is hoping to get the D-Jet certified for (35K - 45K
feet) at a later date?

http://www.diamond-air.at/download/productfacts/d_jet_factshhets.pdf
(US Version) D-Jet:

Normal Cruise Speed .............315 kts TAS (583 km/h)
Long Range Cruise Speed ....240 kts TAS (444 km/h)

Max. Take-off Weight .............5,071 lb (2,300 kg)
Empty Weight ..........................2,590 lb (1,175 kg)
Payload at max. Fuel .................505 lb (229 kg)

Fuel Capacity .............................291 US gal (1,100 lt)

Max. Range ...............................1,351 nm (2,502 km)


Team MontJet