I have no reason to doubt your MU2 experience, but the numbers don't pass a sanity check. Lets say the SF50 has a 250 cubic feet cabin at 8000 feet. At that altitude, there's only 15 pounds of air in it. So you're saying you dump the entire cabin volume overboard once a minute. Hold on to your hat.

I did some more googling, and found a rule of thumb of 500-1000 fpm leakage rate for jets on a forum post by someone who would know. Go back to a 250 cubic foot cabin, and I'm getting around 0.5 lbs/min for 1000 fpm. (And I bet the SF50 would be on the lower end with a once piece composite cabin).

So lets call it 1000 fpm, I get 7 minutes for free (8000 can drift up to 15000, and is this is very likely how Cirrus planning to get it to FL280), and then I just need a supplement to keep it at 15000.

That's besides the point and not applicable to this situation.

Everything you guys poo poo the SF50 over is widely known knowledge. It's not some secret. It's extremely basic stuff.

Yeah..... Or you guys are totally wrong.

What you are suggesting is the equivalent of Apple releasing an Iphone that runs on coal. Everyone knows from the get go it's not gonna work out.

Many, many engineers in the industry would already know that it wouldn't work if what you say is true and it wouldn't get past the drawing stage.

I don't think Cirrus has 1 engineer running this whole thing. They have a bunch. They've been flying the SF50. They could have pulled the plug at any time or switched it to a 2 engine design at any time. They're far enough along to know by now if they're wasting their time.

What you suggest doesn't make sense. But I'm willing to hold an opinion til it's released or abandoned.

Or Coke trying to develop a new Coke?

Still a bad analogy. Coke was getting their asses kicked in the Pepsi challenge.

The SF50 isn't a Pet Rock. It's takes years of development. Too many opportunities to back out.

Right Coke is a small company with no research department.

Point is they got it wrong!

50 lbs/min is a huge amount of air and would represent the absolute worst case.

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.

I'm not qualified to judge the technical performance specs of the SF50 relative to other jet options. I trust guys like Steve and Mike that clearly have this knowledge when they say that, on paper, the SF50 doesn't makes sense. Or make as much sense as existing alternatives.

But when Cirrus made the (brilliant IMHO) decision to design the SF50 as a beautiful v tail, they completely changed the game to being about emotion and marketing, and less about pure technical parameters. With a focus on their current SR base as their target market.

With that as a core business strategy, I doubt the initial SF50 buyers will do any comparison shopping or care that their jet isn't as technically efficient as others they could have purchased. They have that upgrade path today. I doubt the majority of new SR22 buyers considered buying off the used market. For many, I presume, it was straight to the Cirrus dealer.

When SR drivers head back to the dealership to upgrade to the SF, what they will be in possession of is the coolest personal jet on the market by a country mile and everyone on every ramp at every airport will watch in envy as they arrive and depart. For many years to come. Arrival of any other jet? Boring non event. Hey look at that great Phenom? Who cares.

So my money's on tech specs taking a back seat to ego and emotion, and Cirrus selling a boat load. With one caveat...as long as it meets a min mission profile. And I have to believe, as Jason does, that Cirrus wouldn't have gotten it this far if they thought it would not.

For me, emotion will drive the purchase decision, with a little benign ignorance thrown in to avoid getting hung up on technicalities.

Carry on.

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.

http://www.coca-colacompany.com/stories ... -new-coke/

Kinda interesting. The taste tested the new coke like crazy, but missed the brand identity.

Tim

Almost agree. The operating cost must be within some acceptable margin. Even if more then the Meridian or the TBM900 (closest planes I can think of in terms of capability/price); it needs to be acceptable. For most of the target market, I would expect that to be with 10-20%.

Tim

PiperJet

The PiperJet was announced in October 2006, as a competitor to the twin-engined Eclipse 500 and Cessna Citation Mustang. The aircraft's fuselage was the same cross section as the propeller-driven Piper PA-46 series, with a four-foot increase in length.[2] It was to be capable of carrying up to 7 passengers and cruise at 360 knots (666.7 km/h), at a maximum altitude of 35,000 feet (10,668.0 m). Maximum range was expected to be 1,300 nautical miles (2,407.6 km), with a full-fuel payload of 800 pounds. Piper selected Williams International to supply its FJ44-3AP turbofan engine for the PiperJet.[3]

Due to the engine being mounted above the center of gravity, power was highly stabilizing (addition of power would push the nose down), which could have been disconcerting to pilots. Initially, Piper designers incorporated an automatic pitch trim system to coordinate horizontal stabilizer angle of incidence with power setting.[4] This system was later replaced by a vectored thrust nozzle, developed by Williams International, which resulted in reduced weight and simplified manufacturing processes.[5]

A design feature of the aircraft was the use of a straight duct air intake design for the vertical stabilizer (tail) mounted engine, similar in engineering design concept to a McDonnell Douglas DC-10, rather than the s-duct arrangement of most trijet aircraft designs such as the Dassault Falcon 900.[6]

A selling price of US$2.199 million in 2006 dollars was initially set and as of February 19, 2007, Piper announced that it had received 180 pre-orders. An entry-into-service date of early 2010 was initially anticipated, later changed to 2011-12. In October 2009 the company indicated that it had delayed the delivery of the first customer aircraft to mid-2013 and had informed depositors.[7][8]

The PiperJet did not enter production and in October 2010 Piper announced it would instead develop an aircraft with a larger circular-section fuselage known as the Piper PiperJet Altaire.[2][9] The 160 customers who had placed orders for the PiperJet retained their delivery positions with the new aircraft and at the same $2.2 million price.[9]
Altaire

Based on the PA-47 PiperJet prototype, the Altaire featured a slightly larger fuselage with a rounded cross-section, and included a conventional control yoke for flight control, as opposed to the original PiperJet's side-stick controller.[9]

Piper had been tooling up its facilities in Vero Beach, Florida (USA) to build four Altaire prototypes to be used for FAA (safety & performance) certification of the aircraft through 2013. First delivery of aircraft to customers was scheduled for 2014.[10] The first flight was expected in 2012.[11]

The fuselage of the original Piperjet was designed using the Piper Meridian single-engine turboprop as a template. The new owners of Piper, Imprimis, found fault with this design prompting a revision without direct reference to the Meridian. According to Piper CEO Geoffrey Berger, "We wanted to give our jet customers an even roomier light jet that incorporates a scalable design, paving the way for a future family of competitive business jets,".[10] The new fuselage design provided an additional 4 inches of headroom and nine more inches of elbow room and does away with a hump in the cabin floor that accommodated the wing spar in the old design.

The Altaire had been designed for single-pilot operation allowing one passenger to occupy the co-pilot's seat. Combined with 4 passenger seats in the cabin behind the flight deck, the jet would typically have seated 5 passengers. The cabin would have been specially configured to add an additional seat such that a total of 6 passengers can be accommodated in addition to the pilot. There was 20 cubic feet (570 L) of baggage space behind the passenger seats and another 20 cu ft (570 L). of heated but unpressurized space in the nose of the aircraft.

The Altaire would have been powered by the Williams International FJ44-3AP. This model of engine employs a "passive vectored thrust" design that helps compensate for nose-down pitch of the aircraft when power is increased as a result of mounting the engine relatively high up in the tail. Piper estimated that this engine would get the Altaire up to a 35,000 feet (11,000 m) maximum cruise altitude and a 320 knot cruise speed. Maximum cruise speed was projected to be 360 knots. The aircraft was expected to have a 1,200-to-1,300-nautical-mile (2,200 to 2,400 km) non-stop range.

The aircraft was expected to retail for around US$2.6 million, 'standard' equipped. Piper estimates variable operating cost at about US$730 per hour. This compares with about US$870 for the comparable model Cessna Mustang.
Cancellation

On 17 October 2011 the company announced that the PiperJet Altaire program was "under review". Piper's new interim CEO, appointed that same day, Simon Caldecott said, "This is being undertaken to ensure the company is properly aligning business goals and light-jet market forecasts with investment strategies and economic forecasts." The next day, on 18 October 2011, AVweb editor-in-chief Russ Niles called for the project to be ended, calling it "unrealistic" to pursue the design in the face of Federal Aviation Administration opposition to certifying a single engined jet to 35,000 ft (10,668 m) and the lack of economic reasoning as the aircraft would cost the same as most twin-engined jets. Niles called on Piper saying, "the sooner it ends its "review" of the project and puts a bullet in it the better."[12][13] On 24 October 2011, despite the Altaire's development being "on schedule and on budget", the program was indefinitely suspended by Piper due to economic issues, with the company laying off a number of workers who had been assigned to the project.[14] It was stated the company would entertain offers for the PiperJet/Altaire project.[15]

From wikipedia FWIW

http://www.coca-colacompany.com/stories ... -new-coke/

Kinda interesting. The taste tested the new coke like crazy, but missed the brand identity.

Marketing designed the airplane, at least in concept, to appeal to piston pilots.

Piston pilots mistakenly want a single engine jet because they think a single engine jet has the same benefits as being a single engine piston. That is, cheaper to operate, simpler, lighter. An SEJ fails to achieve those benefits in any meaningful way.

They didn't ask anyone in engineering what to build, at least no one with actual jet design experience. By the time engineering is told to build it, the concept is not up for discussion.

Customers are actually quite bad at defining what a future product should look like. Customers only have half the equation, what they want, and not the other half, what is feasible/elegant to build. If a company is fully "customer driven", it will be in bad shape at some point.

All the twin jet makers have smart people, too. None of those smart people are designing SEJs.

All the SEJs contenders have also quit. Guess they got smarter as they looked into it more.

There is only one left.

Mike C.