Only problem is, the engine thrust rating is static and sea level. You won't get 1,800 lbs of thrust from the engine when going 300 knots in cruise.

In a cruise configuration for a jet engine, it is usually 2 to 3 lbs thrust per HP, 2.5 lbs thrust per HP is a rough rule of thumb.

This makes sense as your method means I'd have to put on a 1,660 HP (0.92 times 1,800 lbs) turboprop to fly the SF50 with the same performance. That makes no sense, right? My MU2 has 1,400 HP and flies faster at heavier weight. If we use the 2.5 lbs thrust figure, then the equivalent shaft engine is 720 HP (1800 lbs / 2.5), like a TBM 700, and that makes eminent sense.

Mike C.

You forgot about derating.

At FL250 in cruise, the SF50 is burning 65 GPH (Cirrus published number). That's because the FJ33 is derated in the SF50 such that it can maintain sea level power to some altitude, and only then does it track air density. So you get roughly 50% of sea level thrust at FL250, not 37%.

Mike C.

Ah, the old stats versus stats game. What to leave in, what to leave out, over what time period to measure, you can make them say anything you want with various manipulations.

Paul Bertorelli in Avweb wrote an article where he said the SR was 1.6 fatals/100K, and the Corvalis was 1.0. A few years prior, it was worse ratio than that.

http://www.avweb.com/blogs/insider/AVWe ... 016-1.html

Give Paul a call and tell him to write another article to fix his "mistake", he's generally supportive of Cirrus.


It has been better lately, no doubt. The question is if this is a blip or a trend. Time will tell.


An MU2 pilot can relate. :-)

In both cases, the answer is the same, training and education.

Mike C.

Mike, easy on the posts, let other's get a word in edgewise......

paging Jeff 1 or 2

Good chance it won't.

Their sales guy just email me TODAY with this:

"The Vision SF50 program is currently on track to deliver the first customer aircraft by the end of 2015 – and, if all goes well, we anticipate building about 75 units in 2016"

So by 1/1/2017, Cirrus says 76 deliveries.

I say zero.

Anybody else want to guess the number?

Let's see who is closest.

Mike C.

Yes.


Because being shot at is a wildly different problem space than personal aviation.

Mike C.

True for piston twins like the Baron versus a single Bonanza which was the example given for KJAC.

Not true for jets, thrust is thrust as you say.


All engines, twins climb better than 3 and 4 engine airplanes. Think about it.

Mike C.

You've assigned emotion to a logical argument. Is that how you cope with not agreeing with it?

I'd love Cirrus to succeed, and one way to do that is stop doing stupid things like an SEJ.

Mike C.

Are we getting close?

37 pages of banter on this topic. Who the heck has the time in their day to devote to arguing and bickering over the projections of a product which isn't even to market yet? Perhaps I'm doing something wrong but at the moment I need to spend the majority of my day running a business and developing new clients.

However I can provide a couple cents worth of feedback here...

I'm probably one of the few that worked on a single engine business jet. It was the first iteration of an aircraft called the Century Jet which later became a twin. I can tell you first hand that a single engine commercial jet offers many, many technical challenges that you simply do not have in a twin. There have been several attempts at a private SEJ in recent years, including the CenturyJet, Visionaire Vantage, Diamond DJet, PiperJet and now the Cirrus SF50. Engine positioning, inlet flow, high thrust line (and accompanying large pitch changes with thrust) are only the beginning of the challenges. The bigger challenges are the systems engineering which have very limited bleed air to work with in order to run them.

I think Cirrus has done as good a job as any of those mentioned mitigating many of the flow and pitch issues. It remains to be seen how well they will mitigate the systems issues. I can tell you this that I wouldn't want to be the engineer in charge of that development as the number of technical challenges they have will be great. Yes, it will be a big compromise. Yes it will be somewhat range and efficiency limited. Yes, other aircraft near the category may offer better overall utility. Is there a market for it? I certainly believe so and it's indicative of their book of pre-orders. Will it be a raging market success? Who the heck knows. It's all speculation at this point.

I for one applaud their efforts to continue to innovate and bring new, unique offerings to the market. I wish them the very best of luck and can't wait to fly in one.

Yup, you are.

When potential customers hear you own a Beechcraft, they trust your judgement and come to you.

A 01:37 post is telling

You've assigned emotion to a logical argument. Is that how you cope with not agreeing with it?

I'd love Cirrus to succeed, and one way to do that is stop doing stupid things like an SEJ.

Mike C.

Tells what? Some of us do not need a lot of sleep.

Tim

Tells what? Some of us do not need a lot of sleep.

Tim