what is the most economical piston (single/twin) aircraft

[azeman]

I heard that the DA42 one of the most fuel efficient so wondering if there's any others?

[AdamFrisch]

Tecnam P2006T with the Rotaxes. And in pure fuel burn, the Aerostar is one of the most efficient due to its sleek low frontal area with its thin, short wings. As for singles, I don' really know, but the Mooneys have always been good on fuel.

[Silvaire1]

The Cri-Cri is an fuel efficient twin. So is a Boeing 757. High miles per gallon is no use if it doesn't accomplish some desired task like carrying X number of people from A to B. Or alternately amusing a single pilot for one hour while going nowhere. Its harder than it seems to calculate and compare efficiency.

The Vari-Eze is a notably efficient single (195 mph/two pax/6.5 gph) and if miles per gallon at useful speed was my primary goal, that's what I'd be flying.

[silverknapper]

With the greatest of respect this question shows a bit of ignorance of aircraft in general.

Define economical. Yes a diamond twin star sips fuel. But it's unreliable and maintenance intensive. Plus depreciates like a brand new Vauxhall.

Tecnam sips fuel also, if you like rotax engines. Very slow and it has no legs and poor range payload. It's a training/ survey machine pure and simple.

By the same argument an old Aztec is economical. Burns more gas, doesn't depreciate.

What do you want your aircraft to actually do?

[Rod1]

MCR01 Sportstar 155kn on 18.5lph Mogas

MCR4S 120kn 4 seats on 18.5lph Mogas

MCR TwinR 4 seats 175kn on 37lph Mogas

http://www.dynaero.com/wp-content/uploads/2011/10/4s.jpg

http://www.dynaero.com/wp-content/uploads/2011/10/TWIN2-bg3.jpg

Rod1
V=MCR

[Mark 1]

You need to define the mission more closely to get a meaningful answer.
Are you factoring speed and payload.

Helium filled balloons will give you infinite MPG but rather limited utility.

Motor gliders and electric motors are very energy efficient
(see the winner of the CAFE Green Flight Challenge) (http://cafefoundation.org/v2/gfc_main.php). That gave the equivalent of 400 passenger miles per USG at over 100mph, but still has some way to go before it's a practical solution.

A Boeing 747 gives over 100 passenger miles per gallon on a long haul flight.

Fuel costs are typically only 30-40% of the operating cost of a light aircraft, so getting the last ounce of efficiency may compromise other aspects and not give you a nett benefit.

[abgd]

I didn't know there was a twin MCR, but I was going to suggest the related Colomban Luciole which drinks 4.5 litres/hour at 80 knots. Single place. If I had time, I'd build one.

Motorgliders probably score better.

[Pace]

Mark

Point taken but how many really know what their per hour cost really is ? Owners are notorious stick head in the sand creatures!
There are fixed costs which are there regardless of the hours flown and direct operating costs.
Whack in the depreciation/ finance costs and most would be horrified at the actual hourly rate they are paying especially if their annual usage is low!
The saying that if it flies floats or flucks rent dont buy holds true unless your usage is 200-300 hrs per year.
Direct operating costs are important not so much in the whole picture of things but whether a decision is taken to use the aircraft for work that does not warrant that level of expense.
If you are looking at a certain trip there is competition! Is the aircraft cost effective against the competition?
Cost effective is not just a financial consideration but a time one too and reliability of actually getting to your destination.
Its no good having a gas sipping twin which is not approved for flight into known icing etc etc etc.
So its really a matter of choosing the right aircraft for the mission profile you have! If your mission profile is pulling back the curtains on a Sunday morning and its go to sleep unless you see a clear blue sky thats one thing if its to use your aircraft as a reliable business tool that is another!
Pure point to point speed plus fuel used is not the true picture

Pace

[Silvaire1]

Point taken but how many really know what their per hour cost really is ?Does anybody here calculate the hourly occupancy rate for their house over a year's utilization and compare it to living at the YMCA or cheap hotel?

I actually knew a guy until recently who flew his pre-war Cub zero hours per year. Other people flew it free of charge but he couldn't any more. He died in his 90s, enjoying life to the end :ok:

[Pace]

Silvaire

Totally agree but how many of those pilots say that their aircraft only costs them £90 per hour when in reality its £300 per hour.

Yes many might choose a more expensive option because it has benefits in other ways than living in a cheap hotel but do not con themselves into thinking the cheap hotel is more expensive :ok:

Pace

[Silvaire1]

My two cost the equivalent of about £7500/year combined. The affordability of that number is the only aircraft economy I care about. Most of expense is storage and if times get really tough and I couldn't afford fuel I'd rent the house and sleep in the hangar with the planes. :) ;)

[phiggsbroadband]

Hi, for economy you would need to choose a Low Drag aircraft, so that the Thrust is most efficiently used... Hence a low fuel consumption.

This seems to point to a High L/D ratio, which is only available to Motor Gliders or powered Sailplanes, which achieve 30:1 and 45:1 respectively.
A typical Cessna has about 15:1 in comparison.

If you factor in the cost of hangerage, the detachable wings make for easy storage in a trailer. Also the cost of an annual service can be considerably less for Gliders, as there are so many less bits to go wrong.

[Doodlebug]

Now, how to go about converting that MCR TwinR - thingies' trike undercarriage to a taildragger setup, thus ending up with something that almost looks like a real aircraft?

[Pace]

If we are talking twins the bottom fell out of the market due to the massive fuel cost now of Avgas.
Pilots do not want gas guzzling twins which are relatively slow.
On the flip side of the coin MOST pilots choose a twin for most weather flying day and night and that also includes the threat of Ice.
Hence some of the new generation Rotax powered twins which do not really have weather capability do not hack it!
The latest engined twin star running Jet A1 does.
Cirrus have their single engined jet on the horizon albeit negating the single engine drawback with a BRS system
and the Eclipse appears to be coming up to the mark with the total.
Avgas driven twins? Very limited although you can pick them up for next to nothing! Twin Comm?

Pace

[sharpend]

Well I was looking at a Tecnam, but the price grew to circa £125K as the pound is weak, So I bought a Bulldog for heaps & heaps less! True the Tecnam is far more economical, but I think that the money I saved will buy my Avgas for the rest of my life :ok:.

Plus the Bulldog is much more fun.... aerobatic, IFR, night etc.

[abgd]

Just wondering aloud... the most efficient aircraft tend to be relatively slow with a lot of whetted surface area. Gliders need a low min-sink rate in order to catch lift, and they need to be able to fly slowly enough to make safe forced landings as a matter of course.

If you set out to design a small efficient aircraft with class A rather than motorglider stall speeds, sink speeds etc... would it still look like a motorglider?

[EddieHeli]

Cirrus have their single engined jet on the horizon albeit negating the single engine drawback with a BRS system
Yeah, good luck with that BRS in the middle of the ocean, give me the second engine any day.

[AdamFrisch]

I think longer wings, more wetted area, gliders etc will add drag at low altitudes, but will increase in efficiency the higher you go. And the opposite for aircraft wit less front surface. So down low the smaller and the higher you can make the wing loading, the better. Up high it's the opposite.

[Maoraigh1]

If the OP wants overall cheapest for hours in the air, would a VP1 be best?

[Ebbie 2003]

Cheapest per hour in the air?

Cheapest per mile over the ground?

Cheapest per passenger mile?

Flying need not be expensive - I bought my Archer last year expecting a cost in the B$300-400/hr range for 50-75/hrs per year - one thing was a fear that I wouldn't fly it enough and it would have maintenance issues as a result, so decided to let others rent it, expecting an hour or two a month.

Turns out I can rent it for closer to 150hrs per year at B$400 - it generates a profit that offsets my cost - even with my five figure insurance premium engine fund, hefty remote location annual costs (shipping parts, duties, customs broker fees etc) and $15/USG fuel it costs very little - I'll not say how much per hour (you'll not belive it), but it's less per hour than I paid for a frothy coffee last time I was in London.

According to my sensitivty analysis when I cut the hourly rate in the summer, my flying will become cheaper with greater utilisation - would like to get to 350/hrs per year.

The cheapest airplane is the one that is commercially utilised (in my case I am in the relatively unique position of being a virtually monopoly position (one of only three four place singles available for rent in the country - there are only six GA single airplanes, one's a microlight and two haven't flown for a couple fo years) came as a surprise to me - so I too can say that the difference between what I expected it to cost and what it actually cost are hundreds of dollars apart.

[peterh337]

It's a silly question, with no answer.

[soay]

It's a silly question, with no answer.
I disagree. It's a naive question which has elicited all the preceding answers. The net effect has been to make people think about total running costs and fitness for purpose, which is definitely not silly!

[Pace]

You have to work out what your mission profile is and select the correct aircraft to achieve what you want.
That mission profile maybe a grass field at the back of your house with 400 meters available to you. You may only fly on blue sky days around the local area.
There again you may use your aircraft for business summer and winter day and night flying UK across the Irish Sea to Cork (I did that 50 times in a Seneca Twin one year)
The question was about light twins as well many which you can pick up for next to nothing because people cannot afford the £200 per hour in fuel alone never mind all the other running costs.
Depreciation residual values are all considerations. Do you buy a trusted and established name or go for some unknown aircraft which will crash in value.
It always amused me that owners buy something like a PC12 at $5 mill to save themselves a bit of fuel and another engine when the depreciation would make that look like a drop in the Ocean and remove the twin engine safety.
This is my point a lot are blind to the actual real costs or do not really want to know.
I have a jet owner whos usage is small his hourly costs are probably £4000 per hour. He could rent a lot of metal for that.
So best advice is to work out first what you want from an aircraft and then look at what fits the profile! Then with your short list work out which gives best value.

Pace

[atpcliff]

When it is available, the electrically powered Cessna-172 will be VERY economical! They are working on an overhaul model....so when your ICE powered -172 times out, you replace the ICE and fuel system with an electric motor and electric power sources.

[Big Pistons Forever]

When it is available, the electrically powered Cessna-172 will be VERY economical! They are working on an overhaul model....so when your ICE powered -172 times out, you replace the ICE and fuel system with an electric motor and electric power sources.

The electric C 172 is aimed at the training market as it only has a practical endurance of 1 hour with reserves. I predict it will be a failure as there is no way to simulate getting carb ice while you fiddling with the mixture control while carrying out a NDB approach on partial panel, and therefore will be deemed unsuitable for training :rolleyes:

[abgd]

Presumably people will still need a longer endurance aircraft to fly cross-country, so they will need to train for carb-heat settings.

I see no reason you couldn't leave the lever in place. Ditto for the mixture lever. If you wanted you could even give the instructor a control box to simulate carb icing and engine failures. Probably a lot safer for pfl training as there's little risk of rich cuts or icing.

My question would be how long it takes to recharge/swap the batteries. That really could be a show-stopper.

[Pace]

All electric will never work especially with aircraft, They may do with city cars but come on ; ) what are you going to do? Pull up to the electricity pump at your destination 10 mins later line back up on the runway fully charged?

More likely part Avgas part electric, Takeoff with conventional power go to electric for cruise and all the time under Avgas power battery is recharging!

Pace

[abgd]

I've spoken to a chap with a motorglider who likes electric just fine. For him, it's just a free launch and possibly an extra option if he can't find the thermal he's looking for. For a glider you also potentially have the option of using your propeller as a wind turbine if you find strong lift, though I don't think anybody's implemented this yet. His battery pack doesn't have the endurance to let him cruise to spain, but that's not what he was doing before anyway.

10 minute recharge times are possible for some of the newer batteries, though whether you want to do that to them is another matter as it reduces their lifetimes considerably.

Personally what I think would be most likely for the immediate future is to use the extra electric power for the take-off, then cruise using a smaller petrol/diesel engine operating flat out at peak efficiency. A 60 hp electric assist could weigh 15kg, but only provide power for a few minutes.

There are electrical aircraft out there that a person might want to fly, that currently have endurances of an hour. A 3-fold improvement in battery capacity, which is feasible within the next decade, would make these aircraft attractive for many purposes.

[RTN11]

Surely the best way would be to have a system where you pull in, take out your battery and replace it with a fully charged one. Thereby paying for the electricity, and never truly "owning" the battery itself.

Same process by which you buy a gas canister and then return the empty when you get a new one. Who wants to own a dead battery anyway?

[abgd]

Personally I think the appeal of swapping batteries is limited. They'd have to be different sizes for every aircraft. They'd be heavy (often 100kg plus). You'd probably have to have some kind of frame to move them about. You'd have to have an access panel on the side of the aircraft which could be structurally challenging depending on where the batteries are stowed. Current technology lets you recharge many batteries in 10-20 minutes so why go to all the trouble of taking them out of the aircraft?

[Pace]

ABDG

I do not know a lot about battery powered aircraft but it would need a minimum range of 500 nm or more to be realistic and not a local area toy!
When you get to destination it would have to have splash and dash capability ie very short recharge time comparable with fuel refill times!
The cars which are available and automatically change from petrol or diesel power to electric as required seems the only practical way ahead for aircraft but as stated I am no expert on this

Pace

[abgd]

It depends what your mission is. The Chipmunk only has less than half that range, and it was very popular. Other than my qualifying cross-country and skills test, I don't think any of my training flights were no more than an hour and a half (though I recall one instructor getting caught out by weather and needing to fly for 3 hours before he could land).

Personally I would jump at an aircraft that cost £20 an hour. It would enable me to keep my handling skills a lot more current than they are. You could also make much cheaper twins for training purposes, because the purchase and maintenance costs of two small electric motors are much the same as the costs of a single larger motor.

If electrical aircraft became popular, you could find that charge times became less than fuelling times - no waiting for the refuelers whilst waiting in a queue. 12 minutes is quite common now for r/c aircraft.

[Pace]

Abdg

With only 1 hour flying time how on earth would you manage with carrying legal reserves usually 45 minutes or more with diversion etc

Pace

[abgd]

Umm... I said that there are current electric aircraft that can fly well for an hour, but that if battery technology improves by a factor of 3 then things will start to get interesting.

What I meant by aircraft a pilot might want to fly was something like a Silence Twister rather than an electrified Daedalus or similar human powered vehicle, which could probably stay aloft all day if someone chose to electrify it.

[atpcliff]

The electric -172 is planned for about 1.5 hours endurance. A normal training flight is about 0.8-1.3 hours in duration. As batter tech improves, then the range will increase.

The cost of the motor, and the reduced maintenance costs, along with no fuel costs will DRASTICALLY reduce the cost of flight training.

[abgd]

Is that an hour's cruise, or an hour's circuit training?

I did my PPL in Scotland and I would have worried had I ever found myself with half an hour's reserves, and at least one local training flight would have ended up in the drink. But that said, anything that reduces costs is welcome and I hope it works out.

[Desert185]

Economy is purchasing the correct tool for the job the first time. Buying the wrong tool that won't get the job done is a waste of money.

Economy for me is having the capability to carry 1,000 lbs on a 5+30 leg from a short, sea level runway (700') and land on a short runway (500-700'). If the plane averages 10-12 GPH at 150 MPH, that's also a good thing. A plane with that capability also yields versatility. Anything else for me is false economy, and the wrong tool.

[Pace]

The electric -172 is planned for about 1.5 hours endurance. A normal training flight is about 0.8-1.3 hours in duration. As batter tech improves, then the range will increase.
The cost of the motor, and the reduced maintenance costs, along with no fuel costs will DRASTICALLY reduce the cost of flight training.

But you cannot send a student off on qualifying cross countries with such low duration?
If they get lost have to divert what then?
Ok it might be useful for circuit bashing or exercises within short range of the field but that is about it.

As stated not a serious aircraft but a an impractical novelty toy.

I would also question the legality of an aircraft setting off without legal diversion and holding fuel reserves even in the local area? The airfield could be shut due to an accident requiring such a diversion.

Will it really be a good training aircraft for Avgas driven pistons which will be the inevitable direction at the end of training or will the students then have to fork out for a 5-10 hr avgas piston conversion negating the cost saving.

Pace