Below an image from my last maximum range flight. It was only 609 NM but still it was still max range.
I hate when I see GS lower than IAS.
Emir wrote:
I hate when I see GS lower than IAS.
At FL300 that’s a thing…
greg_mp wrote:
Emir wrote: I hate when I see GS lower than IAS.At FL300 that’s a thing…
But what could you do in a turbine aircraft, if you have a headwind? You fly low – you burn a s%$tload of fuel, with (somewhat) lower headwind and lower TAS at the same time. You fly high – lots of headwind.
In this extreme case, would really not have yielded a higher GS if you had flowen at say 5000 feet, even if you had reduced the power to achieve the same fuel flow as at FL300?
Sebastian_G wrote:
going a little slower at altitude she/he should better get a JetProp. This project is combining some of the weak points of the JetProp (limited altitude performance)
Who told you that ?
A Jetprop will do 265kt TAS all day at F270 and the engine is a -35 wheras on the project described above the engine is a -135, where is the ‘limited altitude performance’ ?
quatrelle wrote:
A Jetprop will do 265kt TAS all day at F270 and the engine is a -35 wheras on the project described above the engine is a -135, where is the ‘limited altitude performance’ ?
The JetProp is an amazing performer but the Meridian will do FL300 while the JetProp is limited to FL270. Also if you really want to the Meridian will do about 275kt TAS and all this at nearly all typical temperature conditions. But to do so the Meridian has got the -42A engine with an additional power turbine wheel compared to the -34/-35/-135 engines. It is more expensive to buy, it is heavier, costs more to overhaul and uses more fuel.
The -34 / -35/ -135 seem to be very similar and there is good reason to use them on the PA46 airframe but then better do so on a JetProp with a lighter airframe, ram air recovery and a limitation to FL270. If you go for a Meridian then the -42A engine is really a good fit and its designers did choose it for a reason. Climbing from FL270/FL280 to FL300 the engine will actually get temperature limited while it is torque limited all the time below. But the key is to get RVSM paperwork as the Meridian was really designed for FL300 and this is where it likes to fly. Modifying it with a -135 to fly it lower seems like a bad idea, if that is the plan better buy a nice JetProp instead as it will perform this task much better on even less fuel.
boscomantico wrote:
if you had flowen at say 5000 feet, even if you had reduced the power to achieve the same fuel flow as at FL300?
The issue is that the cruise fuel flow at FL300 (225 pounds per hour for around 255kt TAS) will not even keep the aircraft airborne at ground level. It will need about 250pph to even maintain altitude and do maybe 125kt down low.
In such extreme cases sometimes descending can help but it needs carefull planning and usually you would only descent towards FL200.
arj1 wrote:
But what could you do in a turbine aircraft, if you have a headwind?
This is really a downside of many turboprop aircraft. As nice as they are a jet can actually outclimb a headwind which is not possible with most prop planes. The worst wind is often around FL300 and then towards FL400 and up it reduces to half its speed.
