So what's your point then. Cirrus shouldn't have built the plane because pilots will come in too fast and go off the end of the runway?

So what's your point then. Cirrus shouldn't have built the plane because pilots will come in too fast and go off the end of the runway?

Allen,

I should have more specific. There is a big difference in energy due to smaller mass and much slower speeds.

From a practical perspective, you are correct. The SF50, like the Eclipse.... will go off the end of the runway and create brown streaks on the seats.

The only real difference between SF50 and other light jets and SETP (excluding the Eclipse), is that the plane really is sized about the same as many piston planes, it is not "intimidating", and is priced much closer to "piston prices".

The Eclipse Canada could potentially match Cirrus in many ways, and even exceed range and speed. But does lose on seats.

Tim

It is not intimidating but still is a turbojet. We will see if it should be more intimidating. Since the time of Thurman Munson pilots have underestimated how intimidating flying a turbojet really is or should be. Even a light jet.

Turbofan...

I just read Tom's article (which I thought was very good). I've been following this thread periodically and have around 800hrs in an SR22 from 2001-2006 so it's somewhat of interest. Note that I haven't ever flown a turbine anything. I do very much enjoy reading what the more experienced of you write, and think this forum has a great atmosphere (this coming from an outsider who doesn't participate much at all).

So to jump in...
The plane doesn't approach at jet speeds, it approaches at heavy piston SINGLE speeds. And it's under 6000lbs when landing. So it has a bit less energy to dissipate than a 58 baron (500lbs lighter, but 10kias faster). Yes, there's no prop disc to slow you down, and there's some thrust, but people like to run Mooney's off the end of the runway too. Name a plane, and someone will land it too fast and run off the end of the runway.

Allen (great name, by the way) - do you think the issue you describe is due to the powerplant or the airframe designed around the powerplant? This thing doesn't seem to have the performance envelop of a jet, even though it has a jet strapped to it's back.

SR22's are rather tough to slow down, no gear and no speed brakes and a low flap speed. So transitioning SR22 pilots may have a head start. The jet's Vfe is 190 and Vle is 210, so mixing it up with "real" jets on a 160kias approach at a bigger airport should be easier than in an SR22 as far as slowing down goes. Doing that in an SR22 is possible, but it's definitely a fun exercise in energy management and the old STEC55x wasn't up to the task. My airline pilot friends say slowing a real jet down for the arrival has a learning curve too.

Vmo is 250kias. So the 10k speed limit is irrelevant, though the 200kias one could be in the decent.

Anyway, not in my budget anyway. But it's interesting because it's so... different. And folks don't know how to categorize it.

The SF50 has the aerodynamics of a jet. It will have a learning curve. And with the SF50 you have few tools to rescue a pilot from sloppy flying. It is the nature of the beast.

Slowing down in the air is easy in a jet. Slowing down on a contaminated runway in a jet can be more difficult. That prop is a big air brake on the ground helping you.

The Vmo came up with the assumption of a 300 kt block speed. A good portion of the flight in climb and descent and approach is going to be spent below 250 kts.

I find nothing that says the SF50 has anti-skid brakes. The EA500 does not.

Depends how long the runway is and how slick. Slow speed doesn't matter when you have no drag alternatives other than brakes to rely on.

And you assume the landing is at ref speed. For many reasons too many turbojets are flown too fast on landings.

Eclipse has antilock brakes, SF50 has a single use drag chute....

They're going to sell lot hot cakes.

Peace,
Don

Just trying to learn - how are the SF50's aerodynamics that of a jet rather than, say, a 58 baron? The SF50 stalls dirty at 67kias, the 58 at around 75 (the newer SR22's list 61). I haven't flown the SF50, but assuming (big assumption) that they tried to get the wing to fly as similarly to an SR22 as possible, the plane will be a bit nicer flying at the bottom of the envelop than a baron.

This plane will touch down around 70kts and you'll be under 5550lbs. There's not much energy from there relative to any jet ever built. If I recall, at Delta they start stowing thrust reverse at 80kts on the 738.

I get that my lack of experience with higher performance airplanes makes me typical of the person you're trying to educate on jets vs pistons (and this is how I learn), but to me, the SF50 looks like a piston plane or STEP with a jet strapped to it. It's max operating mach speed is 0.53 and ceiling is FL280. It's slower than a lightly built Evolution, Epic LT, and TBM. A blackhawk kingair 350 is faster and flight 7k ft higher.

Do you understand the difference in the aerodynamics of a Cirrus vs. a Baron vs. a Turbojet?

Having props or not having props make a big difference in both the thrust and drag at various times in the flight profile. A Barons props on the wings and the immediate prop wash over the wings give the prop twin responsiveness to power changes that a turbojet does not have. Both in adding power and reducing power.

As I said earlier you have more tools to manage landing and stopping a prop plane then a light turbojet.

How is prop wash significant in the landing phase (other than a missed)?

What "tools" does the SR22 have to land and stop that the SF50 doesn't? Prop drag?...c'mon

The tire size of the SF50 is surely increased enough to accommodate the gw increase...which should also allow for greater brake disc diameter. This isn't complicated.

How is prop wash significant in the landing phase (other than a missed)?

What "tools" does the SR22 have to land and stop that the SF50 doesn't? Prop drag?...c'mon

The tire size of the SF50 is surely increased enough to accommodate the gw increase...which should also allow for greater brake disc diameter. This isn't complicated.

Nope, it isn't.

But many more pilots run light turbojets off the end of runways then prop planes. Tell me why?

Prop drag is HUGE.

Blown Lift is a thing.. If you are low and slow, and pour the coal to it in a multi engine prop of conventional layout, the increased propwash will increase lift while increasing thrust. Plus turboprops and pistons tend to be more respoonsive to power changes. Some jets I've flown, you add power and then 2-3 seconds later it's there.

Brake energy. I don't have the data, but it's there. You land in a jet, you are not only taking the bulk of the kinetic energy and turning it into heat, you are also having to deal with residual thrust.