The P180 is not quite that efficient at 90% of V speed, but pretty close. Also consider the higher weight (and payload) of the V. Here are some charts from the older P180.

Hmm, my interest has waned a bit seeing these charts.

My trip yesterday was 408 KTAS, FL430, 1000 pph. That is 2.45 lbs/nm.

Max speed for P.180 is 389 KTAS, FL280, 780 pph. That is 2.01 lbs/nm.

Throw in a 50 knot headwind like I had (and was similar at FL280, winds die off in the 40s), the numbers get closer together.

At economy cruise, P.180 says 308 KTAS, FL390, 390 pph, 1.27 lbs/nm.

But that's 308 knots! If you are in the 30s, where 100 knots winds are quite common, you will be hurting bad.

Somehow I had the idea the P.180 was a 370+ KTAS at FL410. It isn't really, it can't get that high until it is very light, and it is a 300 to 350 knots airplane in the 30s depending on how much fuel you want to burn.

Mike C.

You get at least two or three advantages over the P180 by paying for the extra fuel in the V. Fly over more bad weather and headwinds, more speed, and more payload. But you miss out on that Italian styling. And grass strips (the whole reason I brought up the P180).

The P180 operator I know here in Kuwait is planning to buy a Premier 1A. Not as a replacement, but as an additional aircraft. I personally believe if he's getting a jet he should think bigger.

Like most things in life, you get what you pay for. You can save money, but it will end up costing you in other ways.

P180 Avanti I really likes FL370, 370kts on around 600lbs/hr total. Lower faster and more fuel. Higher opposite. I can reliably do 390kts at FL280 but I am burning 800lbs an hour. So you are a jet down low and a t prop up high.

Mike - you must have cheap fuel at home drome. I do not. That really penalizes the jet.

It's just terrible how much Jet-A prices have gone up. A 33% increase here in Kuwait, from $2.25 a gallon to $3.00 a gallon.

Charts above suggest max cruise at FL370 is 357 KTAS (mid weight) and 520 pph, so you are a little faster and more power than the charts. This would happen on colder days.

370 KTAS at 600 pph is 1.62 lbs/nm.

If I fly FL370 and 370 KTAS, at mid cruise weight, I'm 940 pph (per book, have no actual data), or 2.54 lbs/nm. But that's a stupid thing to do.

At FL430, 370 KTAS would be 840 pph, or 2.27 lbs/nm (per book). These operating points are well below max cruise.

My actual observed performance recently was 408 KTAS 1000 pph, 2.45 lbs/nm, at FL430, about ISA. I could slow down and improve that somewhat, probably to at least book efficiency of 2.27 lbs/nm. That makes me use 40% more fuel per mile than the P.180.

My plane seems to be faster than book. I attribute this to being near the rear CG limit and to Cessna book numbers being conservative. Most Citation owners report doing better than book.

If you fly into a 100 knot winter headwind, as often occurs on my west coast trips, the faster airplane penalties decrease.

The P.180 would save me fuel and has other advantages, but it isn't clear to me my cost per mile is actually that much less than my V when considering all costs and mission factors. I'd say the cost advantage per mile is no more than about 30% I'd say.

Having higher altitude capability helps. My recent flight at FL430 allowed me to top a nasty weather line (since the weather snapshot is mid cruise, imagine it stronger and slightly further east when we crossed it):

At FL400, we would have been in the tops that were full of precip and lightning. You would need to divert a pretty long way to get around such a solid line. We stayed high to cross it and then dropped down at 4000 fpm after passing it (which was just at flight idle, no speedbrakes, BTW).

This sort of narrow advantage does not occur very frequently, but when it does, it sure is nice.

Mike C.

No doubt jet has advantages.

My plane is faster than book on more fuel. Seems common for older ones.

Annually about 80k difference between Ultra and p180 or about 36% more at current fuel prices I pay. If you had your own farm or super cheap gas that delta would erode.

I have been surprised how many days I wished I could climb to FL430 or FL450. Definitely a first world problem.

Your plane sounds faster than other V and Uktra owners I have spoken to. They don’t all seem to be getting 400kts up high.

I'm sure there will be days where I wish to go higher than FL450.


The book agrees with them.

In my case, I am lighter than average and I run mostly up against the rear CG limit. These two things are outcomes of the Garmin avionics upgrade that dropped 380 lbs. Aft CG and light weight increase speed.

I also have minimum antennas. No TCAS arrays, no HF wire, no ADF, etc.

I was a little surprised at how good it was at FL430. I expected more fall off than I got from reading the book numbers.

Maybe my setup is lying to me? I have two ADCs, and my pilot's side is about 3 knots faster than the copilot's side, so they mostly agree.

When I check groundspeed against winds aloft forecast, it seems like I am getting the true airspeed displayed.

I think it is mostly the aft CG. V and Ultra tend to be nose heavy with heavy avionics up front and heavy interiors.

Mike C.

How many grass strips in the US are a good match for the P180?

How many grass strips in the US are a good match for the P180?