Is this a good charter offer (Mooney)

what_next wrote:

So much, really? One of my flight instructor colleagues owns a Mooney (don’t know which one though, I was never able to tell the difference) and claims that his uses only 35l/h. But as usual: Never believe what owners tell you about their cars/houses/horses and aeroplanes

There are huge differences in consumptions depending on the engine used. 35 lph sounds like anything between a C and an J model, which have 180-200 hp engines. My C will do between 31 lph (long range cruise @ 130 kts) and 40 lph (high speed cruise @ 150 kts).

The Bravo is a very different animal altogether, it has a 270 hp Turboengine and is also massively faster.
It will fly up to 200 kts @ 17000 ft burning around 17.5 GPH (65 lph)
It will fly at a more sedate 190 kts @ 15 GPH (57 lph) and a quite respectable 170 kts @ 13.3 gph (50 lph)

So 60 lph as a quick calc value is probably not too far off. However, with this kind of speed you get quite a lot more distance covered as well.

To cover 500 NM with a Bravo will mean it will burn some 160 liters at high speed cruise or 150 liters at 170 kts, which is not a very big difference but takes longer.
To cover 500 NM with a J model will mean it will burn around 120 Liters, the same with a C model at eco cruise (the C will burn around 135 liters to do 500NM at max cruise).

Mooney effectively said good bye to the efficiency at all cost doctrine when they introduced the big bore models. But it is always worth to do a calculation over distance than by hour only, as the results (increased amount of fuel over the legacy models) is often not as brutal as it may seem when the speed is going into the calculation as well and not only fuel flow.

Mooney_Driver wrote:

The Bravo is a very different animal altogether, it has a 270 hp Turboengine and is also massively faster.
It will fly up to 200 kts @ 17000 ft burning around 17.5 GPH (65 lph)
It will fly at a more sedate 190 kts @ 15 GPH (57 lph) and a quite respectable 170 kts @ 13.3 gph (50 lph).

Mooney effectively said good bye to the efficiency at all cost doctrine when they introduced the big bore models. But it is always worth to do a calculation over distance than by hour only,

This very true. So many people compare lph or gph without considering cruise speed. Your numbers go from 200 kts at 3.07nm/l to 3.4nm/l at 170kts.

But this much more efficient than a Piper Mirage at closer to 2.2nm/l. Although it will haul 6 persons at that efficiency.

I know Jason. They are still quite efficient, but interestingly, re NM/L it is hard to beat the vintage models.

The C to J models have NM/liter figures of up to 4.2…. The J model was probably the most efficient of them all, with the C laging slightly behind.

Also consider altitude.

Any turbo plane can do good MPG at an oxygen-mask altitude, but that isn’t a great selling point to passengers.

Leaving out the altitude is a standard disingenuous plane-salesman approach

This is a Mooney thread but it is worth pointing out that the above numbers are not unique among IFR tourer types. I get 150kt TAS / FL100 / 10.5 USG/hr which I calculate at 3.8 nm/litre and that is a fair size cockpit. There really is no free lunch.

What is also often found is that turbo types don’t deliver the best apparently possible efficiency, due to the TIT limitation, so many people run them ROP, not peak EGT or LOP.

Peter wrote:

What is also often found is that turbo types don’t deliver the best apparently possible efficiency, due to the TIT limitation, so many people run them ROP, not peak EGT or LOP.

???

Although running at peak EGT can definitely be a problem, I do not see how running 100°F LOP would give a problem with TIT limit.

I have mapped a number of 4 seater POH numbers into an excel file, data most easilty available is TAS over FF giving a sort of specific consumption.

• Big bore are all 11 to 13 NM / US gal even at altitude.
• The bulk of the population is 12 -14 NM/usg, and that covers anything from a good old PA28 to a TB20.
• The most efficient birds climb to 15 or 16 NM to the gallon in eco cruise (M20J book figure are solid throughout)

The total spread is not very vast.
One’s choice is then more a combination of typical leg lengths vs time (=speed) vs fuel capacity (=stops along the way), and then soft things like panel, cabin size and various praticalities like doors and gear. And availability.

Back to the topic.
JasonC wrote:

The price for this aircraft anywhere other than within 100km of where you live is irrelevant.