Cirrus says 69 GPH, 300 KTAS, at FL280, in their latest "performance profile". If you believe what they say, then the fuel flow is known.

FJ44-1A (525 CitationJet engine) is 1900 lbf (same rating as the FJ33-5A) and burns about 80 GPH at FL280 at MCT. So if anything, the 69 GPH figure might be optimistic.

Mike C.

Someday maybe Cirrus will give us the data on the SF50 to compare it to this:

Someday maybe Cirrus will give us the data on the SF50 to compare it to this:

No that was CJ1, CJ1+ is a bit faster on less FF, M2 even better with 1965lbs thrust FADEC engines and aerodynamic improvements that get it to over 400kts TAS.

It's thread creep, but the Tamarack C525 winglets just got EASA approved and are claiming 900lbs per hour for the first hour and 600lbs per hour thereafter....

That 600pph is at FL410. Compare that to stock numbers. A bit of a savings but not monumental for the cost of the winglets.

http://www.aero-news.net/index.cfm?do=m ... 12b3d78f78

Mike C.

I'm in the beverage business. It's takes 2 seconds and costs ZERO $$ to make a flavor change and have someone taste it. Not the same thing as spending billions on an airplane you know from day 1 won't work.

That is an interesting case study for this thread.

Beech Engineers were adamant that Rutan did not design enough strength into the airframe (even though they had zero experience with composites) and they convinced Beech to add unneccesary reinforcements and weight in the full scale planes after a reduced scale Starship was already flying and performing as forecast. As a result, they destroyed the performance and caused the program to miss its marks. But....those engineers were SURE they were right.

I'm guessing Cirrus learned a lot from that experience considering their success with composites.

That's a good analogy. The big difference would be the Starship was designed to be expensive as hell where as the SF50 is designed to be the opposite.

So Apple's great innovation was buying a slightly smaller disk drive from another company?

Wow, impressive.

Sorry, but the iPod was an exceptionally mundane product from a technology innovation point of view. It plays a sound file.

Cirrus doesn't need to invent anything, either. Building a technically mundane twin jet would have been fabulous. If only Eclipse had not tried to innovate so much they would have been successful, too.

Mike C.

It isn't a flawed basic concept. A light weight twin jet with traditional planform is right. That serves as an example of what Cirrus COULD have built and how it COULD have performed.

Eclipse execution stunk. Everything Eclipse tried to innovate on was a disaster. The Williams tiny jet was a disaster. Friction stir welding makes it to expensive to build in small quantities. The so called "future proof" avionics are "future doomed". The "intelligent actuators" are flaky and a major pain to service. And so on.


The engineers don't get to change the concept dictated by marketing.

It is not clear to me that Cirrus has any engineers that have led a jet design project before.

Mike C.

They have been reluctant to do that despite repeated requests on the microsite for it.

They must have the data by now.

Some numbers from your chart at 9000 lbs:

FL270, 379 KTAS, 1033 lbs/hr, is 0.367 nm/lbs specific range.

FL390, 359 KTAS, 677 lbs/hr, is 0.530 nm/lbs specific range.

Flying 12,000 ft higher results in 44.4% MORE range. WOW!

Al FL270, the fuel flow is 77 GPH for each engine that is supposedly the SAME thrust rating as the SF50 engine. So can Cirrus actually get to 69 GPH? That's a major increase in SFC that has yet to be proven.

Mike C.

Eclipse $6B lost.

Mike C.

If the SF50 were so basically flawed they wouldn't bother building it.

There's no way I would ever ever do what you're proposing Cirrus is doing. I don't know anyone who would either.

We shall see what end product does. Til then it's silly to keep speculating. That video posted already shows the SF50 having much better performance than what has been suggested in this thread. We shall see.