Montblack wrote:

("Richard Lamb" wrote)
There are some MONSTER engines in there!

Agreed.
http://www.togo84.com/spec05_gas_turbines.pdf

http://www.spectrum.aero/downloads/competitive_analysis.pdf
If the Spectrum 33 will burn half the fuel (starting at 500 miles) vs. the
Cessna Citation CJ1, and fly (slightly) higher, and fly (slightly) faster
...mostly because of weight.

Then the MontJet, [now] weighing 1/6th the Spectrum 33's Empty Wt., and
1/5th the Spectrum 33's MTOW, and having 1/2 the number of engines, should
be able to keep up with the Spectrum 33 while burning less than 1/2 the fuel
of the Spectrum 33.

1/2 the fuel burn is in the neighborhood of 25-29 gph - for flights over one
hour.

So, I'm looking at, hopefully, a number in the low 20 gph range for a 2-4 hr
MontJet flight. Am I not? This flight would be side by side with the
Spectrum 33. (45,000 ft and 415 kts).

If I increase the Empty Weight of the MontJet to 600 lbs, I'm still only
1/6th the Empty Wt. of the Spectrum 33, and still hovering around (1/5th)
20% of the S-33's MTOW.

Not to mention (so I mention it) my significantly smaller profile skimming
through the air. Not sure on the phraseology there.

MontJet: (415 kts/FL450)
(Range: 1,500+ miles)
Empty Weight ............600 lbs (x6 = S-33)
Fuel (4 hrs)..................600 lbs @ 21.5 gph (7 lbs/gal)
Pilot + stuff .................260 lbs
MTOW .....................1,460 lbs (x5 = S33)

Spectrum 33: (415 kts/FL450)
(Range: 2,000 miles)
Empty Wt. ...............3,620 lbs
MTOW .....................7,300 lbs

BTW, I'm using the same engine as the Spectrum 33:
Engine ................................290 lbs
Williams FJ33-4A [1,568 pound-thrust]

Unless a smaller (less fuel burn) FJ22 becomes available! g

http://www.williams-int.com/high/pro...FJ33Planes.htm
Planes using the FJ33 Engine

Team MontJet
Goals:
1. Get that MTOW under 1,200 lbs.
2. Get that fuel burn under 20 gph for flights over 1.5 hours. FJ22???
3. Partner with Spectrum so they'll let me use their cool new plane-making
system.
4. Don't get dead and don't go dead broke.

First, break numba 4 into two pieces...
4. Don't get dead
5. Don't go dead broke.

That's so we know which one got us in the end.




1000 pounds thrust!


Ok, your empty weight estimate, like everybody elses, is way to low.

At 300 pounds dry weight the FJ33 is certainly the smallest offering
from Williams international. Like they say, "For a new class of jet".

But that only leaves 300 pounds for airframe, cockpit, landing gear,
etc.

And this is not going to be a BD-5 sized plane - not with that engine.
Not with two hours of fuel aboard!

If we are talking about a "Sport Jet" (1200 lbs MTOW) we still need to
find a smaller engine. Something about half that size, or so?

Smaller *Lighter* engine, with a lower fuel burn.

And it's going to need a pretty cool wing to make speed restrictions.

Something like a miniature U2?

Well, at least there are no climb rate restrictions, nor did I notice
any altitude limits (BG)