It is certainly annoying when they attack the person, making the poster the issue, instead of addressing the argument being put forth.

Mike C.

That can be said about any customer who put a deposit up on any plane that hasn't been released yet. Hardly an argument against SF50.

I agree with MikeC. But I think a big part of the argument, which is correct, has to do with the current certification rules. If a single engine jet could fly into the high 30's, the operation economics would shift in favor of the single engine jet (safety maybe another story). Maybe Cirrus's plan includes making that happen somehow? Without that I agree the Cirrus jet is a waste of money, jets need to fly high to make any sense at all.

That would change the range/payload/weather/speed/efficiency equation. In a jet, altitude is everything.


Many of the other SEJ contenders started with aspirations of seeking a high ceiling. Some as high as FL410 (like EA400), others FL350 (like Djet, PiperJet).

To Cirrus's credit, they never started with a totally unrealistic ceiling, accepting they would never get it certified into the 30s. As it is, they seek FL280, which is already higher than the certification limit of FL250, but perhaps within reach by some sort of technical argument or ELOS. It could very well be that the SF50 is limited to FL250.

It is possible to build an SEJ that can go to FL410, you just need redundant pressurization. That turns out to be complicated and heavy enough that adding a second engine is by far the easiest way to do it.


Exactly.

I suspect one of the major reasons the Djet, PiperJet, projects were canceled is someone ran the numbers on the fuel flow if they get limited to FL250 and realized that would doom their projects. The risk the FAA would not waive the rules was just too great.

If the FAA somehow does relax the rules, the SF50 won't be able to use it more than likely since the cabin differential was set based on FL280, so around 6 PSI. Given the size of the cabins and windows, and the weight sensitivity of this design, I consider highly unlikely the cabin was designed to allow 8 PSI, which is what would be required for, say, FL410.

Mike C.

You may be underestimating Cirrus, by a lot. The G5 with the 200lb Gross Weight Increase was planned and executed over years. For example, Cirrus made the gear changes two years before they announced the G5. The Wing spar was done over three years. (This is all from a few different Cirrus sales guys, so likely true).
The point is, Cirrus plans upgrades to the planes and slips in equipment changes in preparation for the final parts to all come together for the upgrade to be announced. This minimizes production changes, and certification hassles.

Tim

Look at the engineering effort to increase gross weight by 5.9%.

To increase cabin pressurization 33% from 6 to 8 PSI would be far more effort, likely requiring new windows and new cabin structure. That is a not a trivial change.

There are also aerodynamic considerations when flying higher, such as stability. So it isn't just a matter of making the cabin hold higher pressurization.

Mike C.

The same can be said about turboprops yet the most common SETP on the market is the Caravan.

A ceiling in the 20s is fine for a turboprop. That is usually higher then their max speed altitude (which for jets is typically in the mid 30s). Efficiency is good in the 20s for turboprops, not so for jets.


208s are used on short haul freight, or bush flying. Not too many 208s doing owner flown personal transportation, the market for the SF50 jet.

Mike C.

Podcast: Cirrus Talks About Jet Parachute Testing
http://www.avweb.com/podcast/Podcast-Ci ... 135-1.html
or
http://cdn.avweb.com/media/podcast/2016 ... Wadick.mp3

Look at the engineering effort to increase gross weight by 5.9%.

To increase cabin pressurization 33% from 6 to 8 PSI would be far more effort, likely requiring new windows and new cabin structure. That is a not a trivial change.

There are also aerodynamic considerations when flying higher, such as stability. So it isn't just a matter of making the cabin hold higher pressurization.

Mike C.

Expecting type certificate submittal by end of Q2, THEN the FAA does its thing. Only after the TC is awarded will deliveries start.

When first delivery? "I don't know". By end of year seems optimistic now.

As to CAPS, a number of excuses provided for why it won't be as effective or needed as in SR series.

One of the excuses was the pilots will be better trained.

"It won't be pull early, pull often".

Paul didn't ask the hard question of "chute by wire" and what happens if that fails.

The reality of putting a chute on a 300 knot 6000 lbs airplane are now made manifest. Cirrus doesn't even want to test it for real. The envelope in which the chute saves you seems far more narrow than in the SR series, so narrow, the autopilot is asked to put you in that region before you can use it.

If I was an SF50 depositor, that interview would cause me concern. The delivery time and the chute capability are less than I was promised.

Is CAPS really all it should be on the SF50?

Mike C.

MIke, why does the FAA does not consider drop down emergency oxygen masks an aternative for certification to say FL 350? Even in an airliner that has a sudden (lets consider a strange incident of cabin blow out of some sort) then back up pressurization would not even cover the emergency; but "drop down" oxygen works for airliners..

Thinkers and feelers... (to quote JC)

Feelers generally don't like it when thinkers rain on their parade with logic.

They will probably sell quite a few to people that want to tell their friends they own/fly a jet. If nothing else, this will bring new people to aviation. How is that a bad thing?

We all waste our money how we see fit, some people are just better at it than others.

It is certainly annoying when they attack the person, making the poster the issue, instead of addressing the argument being put forth.

Mike sure has a lot of well-documented eggs in one basket...

I listened to the pod cast. What I heard is its April, they are flying the first production aircraft (P1), they expect these owners to fly and train at a higher level, they are embracing additional technology with an advanced AP to further reduce the need for CAPS deployments, and they are unwilling to commit to a timeline due to the ball being in the FAA's court.

I do hope they succeed, but I have no vested interest. I don't care if I'm right or wrong. With that in mind, its like we listened to a different podcast based on our perspectives.