For you guys flying above FL250.

[Adam Frisch]

The Jetprop crowd - how often are you in the soup up there? And do you find that there's a huge difference in getting on top more readily at RSVM altitudes, or is it kind of no real difference between FL250 and FL300+?

[swelch]

Sunday I went up to MBS and was in and out of the tops at 230 but was on top at 250. That was right over the front that was moving to the east. Mostly low to mid 20's put you on top 95% of the time.

[Adam Frisch]

Thanks Swelch.

This means I have a fighting chance in my old 680V to see some sun! 

[donv]

I think you'll be fine most of the time, especially in California. I almost always fly at FL270-280 unless it's a short flight, or once in a while when the winds are really bad up high. I'm usually on top, but it's not unusual to be in the clouds.

When I used to fly jets, there were days when we would be in the clouds all the way up to FL410.

But, as a general rule, the higher you go, the more likely you'll be in the clear.

A big question for you, with the 680V, is how much performance the anti-ice takes. in the -5 690s, it used to consistently cost me 10-12 knots of true airspeed. In the 980, I don't know that it costs me much of anything.

[Adam Frisch]

Don, I'm assuming it will take similar performance reduction on the -1 Century engines. Although much better than the -43 engines they came with originally, they run out of steam at around FL220, I've been told. You can get to FL250, but it ill be slow above 20000ft. Add de-icing to this and I'm sure it will get even slower. Also, they only have a 4.2psi cabin at best, so at FL250 you're looking at a 13000ft cabin - not so comfortable for long trips. I think FL250 will be an option to get around wx or above it once in awhile, but the bulk of the flying will be done between FL170-FL220.

I hope to own a Jetprop one day. I like the range, speed and altitude capabilities of them. They seem like the perfect plane for my missions: Long travels, sometimes into tight fields.

[ghancock]

For those of us not so knowledgeable.  When you say it's slower with deice, do you mean just the boots being on the plane or actually using them?  Do the Turbines use bleed air for the deice and that is why it slows it down?

Sorry for the dumb question, just never heard anyone say that before so want to better understand the process.

Thanks,

Glenn

[donv]

Glenn--

They use bleed air for the engine inlets, and electric heat for the props, generator inlets, pitot/stall warning, and the rudder horn.

The boots are just a momentary use thing, and so don't make much of a difference.

[donv]

Adam--

A good thing to know are the time limits on your ignition system. I've become a bit paranoid about ignition over the past few years, and use it a lot. A friend of mine (and highly competent Commander pilot) flamed BOTH engines out on short final due to ice that he didn't realize he had... so now, I run the ignition during every takeoff and landing.

The AFM should have an insert about running the ignition any time there is ice adhering to the spinner, and I've become pretty religious about that as well. Merlins and MU-2s are notorious for flaming out due to ice coming off the spinner, Commanders less so... but still.

[Adam Frisch]

Good tip. On one of the engines I have the continuous ignition system, on the other it's still a bit unclear. We're checking the serial number now. If it's not, I'll swap that asap. I want to be able to run the ignition in heavy rain and ice and will take your lead on keeping them on for takeoff as well.

[Willis]

Good tip. On one of the engines I have the continuous ignition system, on the other it's still a bit unclear. We're checking the serial number now. If it's not, I'll swap that asap. I want to be able to run the ignition in heavy rain and ice and will take your lead on keeping them on for takeoff as well.

Adam, on the 'continuous' ignition system, is it a 2-speed Exciter?  Which maker; Champion or Unison?  [I liked Unisons hardware, but Champion has better customer support].

I know it would be hard to tell with the engine running but a dry start would work to tell what kind of system you have.

Also, do you have a separate Ignition switchs?  You may need to install two new switches. 

As usual; nothing worthwhile is affordable. 

[Adam Frisch]

Right engine had the older limited ignition system, so we're trying to source a used box now to swap it.