Is the Jetprop the right plane for my mission? (and other high performance types)

It’s not trivial, but carrying some 14″×14″ piece of Plywood for each wheel would take care of that.

A Seneca is parked on grass infront of me at base, without any Slabs at all, all year around and never appears to struggle.

Possibly by self sheltering the ground below the wing, he has better results where arriving at already sodden grass would cause him to get stuck like the rest of us?
To be realistic, anything much more than a PA28, DR400 or similar light single is going to need to be very careful about the condition of non-home base grass other than in summer.

GA_Pete wrote:

A Seneca is parked on grass infront of me at base,

A Seneca has half the empty weight and less than half the MTOW of a PC-12. Not sure if Plywood does the trick if you have 1.5t on each wheel.

But in the end it comes down to what has been said before (also on the PA-46): On some grass fields it is no problem at all, others are a No-Go. You need to be quite sure about the actual condition of the ground when you go into such a field with a 2t+ airplane…

Antonio wrote:

I happen to be in charge of a friend’s pressurized 337 that I have been flying the last six months,so I can comment with mostly first-hand knowledge on all three CESSNA’s in this discussion.

I’d love to know what sort of real-world figures the P337 turns in. Is it a modified version with intercoolers etc?

it also can’t deny physics when it come to soft field. in many cases my main concern would not so much be the landing (or takeoff) itself but how get it out of the holes it has dug itself by standing on a soft ground over night…

GA_Pete wrote:

It’s not trivial, but carrying some 14″×14″ piece of Plywood for each wheel would take care of that.

I suggested that, a couple of years ago,to my co-pilot (wife) as to what a good idea it would be, she could crawl under the aircraft with the engine running, place the plywood and I could taxi into position …. she was not amused

quatrelle wrote:

she was not amused

She should have replied that she would be happy to handle the taxi in position part while you, honey, crawl in the mud to put the plywood :-)

A PC12 stuck in the soft grass is not a trivial problem. I hope it has never happened, but somewhere a bright spark might want to use beta/reverse to try and jimmy it out, and wonder why his/her PC12 turned into a tail dragger.

One complication of the PC12 is the wingspan and the wheel-span. Some airports, even quite a good infrastructure airport like Milano Bresso, you need to send a fax (and follow up with several phone calls) to Rome to get a one off permission to use the airport. The easiest way to get the PC12 with a main landing gear stuck in the mud, is using typical narrow GA airport taxi ways, which are not centre line marked, and have sharp turns.

It may be the ultimate Swiss army knife airplane, but there are some/quite a few GA airports where it is not suitable. A 206 might have to fly the last mile.

@HBadger, I think this comes down to the classic ‘you can have two out of three, but not all three’ conundrum. Grass, speed, pressurization. Two out of these, no problem, all three – well, we’re back at the Eierlegende Wollmilchsau. The one that comes closest is a P210, SE or classic.

Btw, I had a look at the airfields you mentioned and with the exception of Wangen-Lachen all have a ‘real’ airport close by. Memmingen, Hahn, Hamburg – all three obviously more hassle but also better ground infrastructure than the little ones in your list.

@WilliamF I will try to answer on my CHAPTER TWO: PERFORMANCE on Cessna P210/SE/337 Prez’d,

A) CRUISE
Our P210 is as light and clean as it gets: no air conditioning, fully enclosed landing gear (later models did away with gear doors), no deice boots, no radar pod.It “only” has an induction air intercooler.
SE’s are typically also heavily loaded, but the above-reported example was deice boot-less
There are also some TKS 210’s in the market.
Our 337 is a 1973 T337G pressurized model, almost as dirty and heavy as it gets with intercoolers, gas heater, air conditioning, speed brakes, full deice, full leather interior, super-soundproofing, STOL LE and VG’s, but no radar pod.

Cruise performance we see is:

• P210: ours is clearly a 200+KTAS plane at FL200 when ROP, 180KTAS at FL100, using about 20GPH. LOP, our usual mode, we see around 5KTAS less at around 16GPH. Most heavier/dirtier P210’s report 5-10 KTAS less. In all cases +-5KTAS depending on weight.
• SE: I have not personally flown it but all reports indicate that it is a 200-220KTAS airplane at FL180-200 depending on OAT. Lower down it is limited by 167KTAS redline.
• T337G: we have only taken it up to FL200 once on an ISA day at Max weight and we saw 190KTAS ROP at about 28GPH. About 5 KTAS less LOP at 22GPH. I assume at medium weights with a cleaner airframe (no STOL/VG’s/AIR COND) it would easily achieve 200KTAS. Lower down at FL140 it does around 175KTAS ROP.

B) SHORT FIELD
Perhaps more pertinent to this thread.

• P210
  Our unmodified aircraft (other than intercooler) sees POH figures. It is not stellar, but very reasonable for such a heavy aircraft. For ref, no-wind take-off distances:
  @4000lbs @SL20C 415m/690m (GND/to 50ft)
  @3700lbs @SL20C 343m/569m
  So in general, a 600-700m runway is easy if there are no close obstacles.
  Flaps20 take-off is allowed (normal is flaps10), which will decrease take-off roll , but it will not affect distance to 50ft.
  Obstacles, rather than the runway length itself is the problem for the P210: lift-off speed is low at 67-70KIAS but acceleration to initial climb speed of 80 KTS is slow unless in ground effect.
  We have flown it several times at an 800m grass slightly soft strip at 3000ft density altitude with 50-ft trees at both ends. Our heaviest take-off was with three male adults, two kids, light luggage and 54 USG (2.3+1hrs or about 350NM range) @ 3650lbs and we did not sweat it. We had however done some progressively heavier take-offs that day to verify performance.
  There are STOL mods available including the Robertson which will use the ailerons as flaps too.
  Landing is shorter, as usual, and with a 72KIAS short field landing speed stopping in 700m is not a problem at 3800lbs, maximum landing weight. I have used also a 500m runway once but that was lighter at around 3400lbs.
  Incidentally, we have also used the aircraft at 6000ft dens altitude on a 400m runway but that one had 14% slope which surely helped.The very experienced mountain instructor and test pilot that we had onboard that day was gladly surprised by the performance for the heavy aircraft: the heaviest one he had flown into those kind of fields.
  As always: use the above figures with care, at your own peril, and verify your own aircraft progressively before pushing it.
• SE: again the same airframe with 50% additional power means the OP’s take-off requirements can be met with ease. No formal data but you can assume obstacles are no longer a problem and so a 600m runway should be easy with proper technique. Reverse will also help on landing, but that depends on how much dirt/grass you care ingesting into your expensive engine.
• 337: ours has the STOL mods and VG’s so it will stall at under 50KIAS in landing config. For take-off the unmodified POH figures for SL ISA are:
  4700lbs 288m/460m
  4300lbs 235m/390m
  We experience approximately POH figures without using short field technique, but that is because our speeds are at least 5KIAS below an unmodified aircraft.
  I cannot confirm on the latter, but on our STOL version take-off distances are better than P210, and landing is way better since approach can be safely flown under 70 KIAS at high weights. Our first few approaches were at 80KIAS and that proved to be too fast with the airplane bouncing as soon as it touched down. 70KIAS does it way better and then light braking will stop it in 500m no sweat. POH figure at MLW (4465lbs) is 243m/510m.
  The easier handling of the 337 also makes it a breeze to stick the landing technique vs the P210.

C) CLIMB

• P210 is typically limited by CHT. On warmish wx at higher weights we typically see 700fpm average to FL140, then waning down to 400fpm at FL200. Lighter weights will simply make it easier to continue the 600-700fpm higher up. Other P210 flyers report slightly worse performance. On two occasions I took-off heavy at 40C and had to limit initial climb to 400fpm to maintain CHT’s below 390F.
• SE this is where it excels at over 2000fpm initial climb.
• 337 sees on average about the same climb performance as our P210 but then I have always flown it at close the max weight, unlike the P210. Limitation is rear-engine CHT and OilT.

Mooney_Driver wrote:

I wonder whether these pressurisation issues are generally a problem with the Silver Eagle, if so, then something is really wrong with that design. I remember having such ear troubles on a jet for a while until we really worked on the outflow valves (e.g. cleaned them massively) thereafter things went a lot better. @lionel, do you have comparison to another Silver Eagle and is it the same?

<shrug> The pressurisation was much improved after I had the maintenance shop test it with a pressure machine, they found leaks and repaired them. I describe the state now, after improvement.

There is a type-specific forum at http://www.p210silvereagle.com/; one can get other opinions there.

Silver Eagle cabin: If one is tall, the cockpit is more comfortable than a PA46. One of the reasons for my choice, along with cheaper turbine, and that although the PA46 is faster, it has less range so on long travels an extra stop makes longer travel overall.