Optimum Altitude for a PC12 Pilatus
Hi,
Can you please help me out on this, it seems like I can't find an optimum altitude for a PC12 anywhere... Thanks in advance. |
How far are you flying? If you are flying the shortest scheduled route in the world from Westray to Papa Westray, a distance of around 2nm, then 1,000ft would possibly be the optimum altitude.
As a rule of thumb when I used to fly a Turbo-Commander we assumed that the optimum level was numerically the same as the flight distance. Therefore for a flight of 140nm the optimum level was FL140. |
As with any airplane, optimum altitude is a function of GW.
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There is a difference between "Optimum" altitude and "Recommended" altitude. As previous posters mentioned, on short flights climbing to optimum could actually result in wasted fuel.
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Most of our routes are around 275nms and the Service Ceiling is 30,000' and we are always climbing that high for that distance, but I heard it from a couple of ATRs and Dash 8's Captains saying that even though their Service Ceiling is 25,000' but their optimum altitude is about 18,000'. So I thought that maybe we are misusing the PC12 for climbing very high.
Thanks for the input so far.. |
Ok so here's a tip, 2 actually!!
1/ look at your PC 12 perf charts 2/ next time try FL 180 and see what the time and fuel burn was for the sector, then compare to FL 250. :ok: |
Exactly!
Surely you have charts that give you TAS and F/B at various altitudes and conditions? But, maximum altitude is rarely optimum altitude if it's performance limited. |
Thanks! Will try to do so but it seems like nobody has never tried to do this with this particular plane. Then I will be happy to be the first one to probably find out the solution of this issue.
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Can't leave wind or ISA deviation out of the equation either.
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Will try to do so but it seems like nobody has never tried to do this with this particular plane. |
it seems like I can't find an optimum altitude for a PC12 anywhere... Edit; As the top item in my Google search for "PC12 performance" included cruise and long range cruise tables (admittedly for sim players, but the tables looked genuine) anyone can find this info at the touch of a button. What's going on? |
The rough rule of thumb that I used on the PC-12 was was (distance/10) + 2000'. So a trip of 190nm I would go to FL210. This, of course, does not take winds/weight into account. The PC-12 is an excellent climber with a very good wing, so you may as well go high and get your fuel burn down, plus have a few more minutes of glide time in your back pocket!
It's been 5 years since I've flown the PC-12, I miss it! |
Thanks El Comat, that's exactly the rule we are using in our Company, in fact + 2000 varies according to the Elevation of point of Departure or Destination or both. After going through Performance Charts and your comments, I have decided to stick on this particular rule of Climbing high and play around with Tail winds as much as possible.
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Given the PC12 speed, winds aloft are a major factor when deciding at what FL to cruise.
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ant1
I totally agree with you:ok:.
Thanks! |
our sectors average around that, flying the 1900 but a good rule of thumb was if less than 1.5 block a 40kt difference in wind we would stay lower ie 12-14k. But then again I don't worry about gliding range
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I got some mates who fly the PC 12 they reckon they cruise at around 20/22,000ft - thats for about 800 NM.
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First of all you have to tell us what kind of PC12 you are flying.
The old PC12 and the NG have a different max. ITT, so different Power and Speed at different altitudes. The PT6 in the NG has a max ITT of 820°, but Pilatus recommends 780° max. The older B engines have 760° max. Useing 780 in icing condition, a heavy weight and flying minimum icing speed takes the aircraft very long to climb to cruising altitude. The older PC12 have different max. Take Off weight. There are 4700 kg for the -47 there are 4500 kg for the -45 and there are still a vew very old aircraft flying with 4200 kg max weight. So tell us the Type and I will be able to help. |
Inbalance
We have old and middle class PC12s 45 series, and we are always restricting our climbing ITT to 720 for longer engine life. I don't have any experience on NG and our Max takeoff weight is 4500 kgs.
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To Natstrackalpha & Agaricus
Google? Ha ha. Well I'm a humble Man who always want to learn and never argues...
I had to ask this Question here because I tried to go through all the Performance Charts without any direct success, TAS for every altitude decreases with altitude but fuel flow also decreases during Climb for PC12. Long range Charts didn't work as well because for Optimum altitude you need good Speed not only low fuel flow. Well I'm a little bit new on type about 400 hours but I'm not an inexperienced Pilot. I managed to get the Optimum Cruise Altitudes for B737s and Dash 8 series through compensations like this and experience on types. Will appreciate your comment more than criticism:ok: |
This may help you to find the optimum altitude:
PILATUS PC12 -45 Maximum Cruise Power Max Take Off Weight No Wind No Alternate 100 NM Alt time fuel 22000 00:33 255 20000 00:33 258 18000 00:33 259 16000 00:33 263 14000 00:32 267 12000 00:32 273 10000 00:32 282 8000 00:32 286 6000 00:32 295 200 NM Alt time fuel 28000 01:00 403 26000 00:59 409 24000 00:58 416 22000 00:57 424 20000 00:57 436 18000 00:57 447 16000 00:56 458 14000 00:56 472 12000 00:56 484 300NM Alt time fuel 28000 01:25 547 26000 01:23 561 24000 01:22 577 22000 01:21 593 20000 01:20 614 18000 01:20 634 16000 01:20 654 14000 01:20 676 12000 01:20 696 400NM Alt time fuel 28000 01:50 692 26000 01:48 713 24000 01:46 737 22000 01:45 763 20000 01:44 792 18000 01:44 821 16000 01:44 850 14000 01:44 881 12000 01:45 908 500NM Alt time fuel 28000 02:15 836 26000 02:12 866 24000 02:10 897 22000 02:09 932 20000 02:08 970 18000 02:08 1008 16000 02:07 1046 14000 02:08 1085 12000 02:09 1120 600 NM Alt time fuel 28000 02:40 981 26000 02:37 1018 24000 02:34 1058 22000 02:33 1101 20000 02:32 1148 18000 02:32 1196 16000 02:31 1242 14000 02:32 1290 12000 02:33 1332 700 NM Alt time fuel 28000 03:05 1125 26000 03:01 1170 24000 02:59 1218 22000 02:57 1270 20000 02:55 1325 18000 02:55 1383 16000 02:55 1437 14000 02:56 1494 12000 02:57 1544 800 NM Alt time fuel 28000 03:29 1270 26000 03:26 1322 24000 03:23 1379 22000 03:21 1439 20000 03:19 1503 18000 03:19 1570 16000 03:18 1633 14000 03:20 1966 12000 03:21 1756 900 NM Alt time fuel 28000 03:54 1415 26000 03:50 1447 24000 03:47 1539 22000 03:45 1609 20000 03:43 1681 18000 03:43 1757 16000 03:42 1829 14000 03:43 1903 12000 03:45 1968 1000 NM Alt time fuel 28000 04:19 1559 26000 04:14 1626 24000 04:11 1699 22000 04:09 1778 20000 04:07 1859 18000 04:07 1944 16000 04:06 2025 14000 04:07 2108 12000 04:09 2179 1100 NM Alt time fuel 28000 04:44 1704 26000 04:39 1779 24000 04:35 1860 22000 04:33 1947 20000 04:30 2037 18000 04:30 2132 16000 04:29 2221 14000 04:31 2312 12000 04:34 2391 1200 NM Alt time fuel 28000 05:09 1848 26000 05:03 1931 24000 04:59 2020 22000 04:57 2116 20000 04:54 2215 18000 04:54 2319 16000 04:53 2417 14000 04:55 2517 12000 04:58 2603 1300 NM Alt time fuel 28000 05:33 1993 26000 05:28 2083 24000 05:23 2180 22000 05:21 2285 20000 05:18 2393 18000 05:18 2506 16000 05:17 2612 1400 NM Alt time fuel 28000 05:58 2137 26000 05:52 2235 24000 05:48 2341 22000 05:45 2455 20000 05:42 2571 18000 05:42 2693 1500 NM Alt time fuel 28000 06:23 2282 26000 06:17 2387 24000 06:12 2501 22000 06:09 2624 There is no performance data for 720° available. Our -45 aircraft is not RVSM aproved, so my performance calculator doesnt show any data above FL280. |
This sounds like a fairly strange question coming from someone who supposedly flies the actual airplane for an actual company. Then his handle is 737lover. Anyone else suspect we're dealing with a simmer?
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Anyone else suspect we're dealing with a simmer? This sounds like a fairly strange question coming from someone who supposedly flies the actual airplane for an actual company. The data above takes a week to be calculated by hand. |
To inbalance
You are a Star that I don't know but maybe one day I will. This information is exactly what I was looking for and now I have it and as far as I'm concerned! This chapter is closed. Will ask you more Qs if necessary through PM. You have just added 100 years more for me to Fly probably by help of God. Let me know when you come to Tanzania one day.
Cheers! |
now adjust these numbers for a 30kt at 14k or 85kt at fl220
300NM Alt time fuel 28000 01:25 547 26000 01:23 561 24000 01:22 577 22000 01:21 593 20000 01:20 614 18000 01:20 634 16000 01:20 654 14000 01:20 676 12000 01:20 696 |
now adjust these numbers for a 30kt at 14k or 85kt at fl220 |
CYXE0300 270/049 +10 -046270/048 +10 -045269/047 +11 -043268/045 +11 -042 CYXE0250 268/050 +09 -046268/048 +10 -044268/047 +10 -043268/045 +10 -042 CYXE0200 263/045 +08 -040264/044 +09 -039266/043 +10 -040267/042 +11 -039 CYXE0150 264/040 +08 -037265/039 +09 -036266/039 +10 -036268/038 +11 -035 CYXE0100 261/038 +08 -034263/037 +09 -034265/037 +10 -034267/036 +11 -033 CYXE0050 256/033 +08 -029259/033 +09 -029261/033 +09 -029263/032 +10 -029 Avg. Trip Winds=> - 38 Headwind - 37 Headwind - 37 Headwind - 36 Headwind FLT TIME==> 1:57(+01) 246TAS 1:56(+00) 250TAS 1:55(-01) 251TAS 1:54(-02) 253TAS Fuel Burn==> 840 Lbs 852 Lbs 873 Lbs 891 Lbs
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last from fltplan.com, ywg-yxe. as you can see you would gain no real benefit from going higher except better gliding range. within 50# burn but faster block speed, engines running cooler, and less time in the climb
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Thanks a lot rigpiggy. All copied:ok:
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