Most fuel efficient twin?
 

Hi all,

I currently fly a cherokee 6-300 and plan on around 60LPH fuel burn. Actual average is 54-56 but it gives a good safety margin and is easy to calculate.
My question is, what is the most fuel efficient twin, per mile flown? I am thinking of trading the cherokee in for a twin as I will be doing a fair bit of IFR in the next couple of years so am looking for something that has a decent trade-off for speed and fuel consumption.

Cheers for the help.

Surely the Tecnam P2006 must beat all the others hands down, in matters of fuel burn?

The DA-42 running on Diesel/Jet-A1 burns 42LPH. What does the Tecnam burn

Efficient twin
 

Perhaps not, I think the Twin Comanche would still come out on top or very close as it is a true 160 kt aircraft. The Tecnam is a 140kt aircraft. Add on the cost of the extra fuel to do 20 miles and the difference would be small.

The range of a Twin Com far exceeds the Tecnam so fewer stops for fuel, also the TBO on the Tecnam is only 1500 hours.

The diamond cruises at 154kts @70% power, however I don't know what a used one goes for today

The DA42 should be up there - it burns about 11 USG/hr at 140kt at low level.

I've been told the p2006 burns about 38 lts an hour


This can of course be MOGAS with 10% ethanol.

Tecnam P2006T burns 10gph full throttle and 8.8gph at economy cruise. Mogas as well. Hard to beat. If you want a cheaper to run twin you'll have to start looking at a Cri-Cri..:)

In terms of fuel cost or fuel volume?

A diesel DA42 is pretty comparable with the Tecnam in terms of nm/gal (and slightly faster), but depending on location Jet A may be cheaper pr gal than avgas.

I seem to recall that you can throttle the diesel DA42 back to some ridiculously low power setting like 40% and get 7.5gph at 120 kts, or something like that.

I really like the Tecnam btw. If only the specs weren't so much on the low side...(620 nm range, cruise 135 kts, ceiling FL150, t/o distance 450m - and a new one is still USD450k...)

Full IFR Twin Commanche with logbooks in perfect order that has been hangered with decent avionics. Watch out for cavitation in the fuel tanks but find one with tip tanks and you can fly a very long way between fuel stops. It's a lovely and very under rated machine. Try the US perhaps where some of them are respected, loved and pampered.

International Comanche Society

If you define "fuel efficiency" as "lowest fuel burn per passenger mile", then you'd probably be looking at the Boeing Dreamliner.

However, since this was posted in PF, your mission is probably not to haul 200+ persons across the oceans. So what is your mission? 4 persons? 6 persons? 8?What is your target speed, range? Budget?

Those specs are poor for a going-places supposedly IFR aircraft, costing that much money.

620nm range is not much good for European touring (for $450k) unless you live in southern Germany and want to pop over to Croatia for lunch, FL150 ceiling is no good for IFR anyway because it won't get you into VMC on top in a lot of non-frontal conditions (it's similar to an Archer), the 450m t/o distance is good though.

I absolutely don't want to start another SE v. ME thread :) but take my TB20: 1300nm range, FL200 ceiling, 450m takeoff roll, and the new cost (2002) was c. US$300k. A potential Tecnam owner doesn't need a PhD to be aware of this stuff.

Ever since Mr Thielert and Messrs Diamond have comprehensively p1ssed all over the twin engine options, I can see the Tecnam being popular with ATPL schools whose prime objective is to fly as slowly as possible (because they charge by the hour, and the punters have to pack X hours in their logbooks) consistently with going just fast enough to fly NDB holds in 30kt crosswinds without getting blown away sideways ;) , who don't care about going places, and who do everything at low levels.

But the options for a serious private pilot are rather poor, which is why I have not done anything "ME" myself. You have a choice of 1950s airframes, most of which were built in the 1960s or 70s, or the DA42 with its engines which are either dodgy or as yet unproven, and that's about it. It's a real shame because the DA42 could have been a revolution.

If you are interested in efficiency have a look at this;

Twin-R

Only of academic interest in the short term. Dyn Aero went bust a few months ago with the twin ¾ of the way through its certification. The company has been bought as a going concern and spares etc are back up and running but no word yet on the plans for the twin. The efficiency comparison charts make interesting reading though.

Tecnam are reported to be working on a Rotax 914 turbo version which should make a big difference to the aircraft.

Rod1

thanks for the feedback guys. Backpacker, I am hoping to use the plane to primarily fly between a cattle property and city roughly 400nm away. Speed wise, anything faster than 150kts would be desirable. Budget wise I am undecided, but have noticed that here (Australia), there seem to be a lot of cheaper twins coming onto the market.

What's the runway like at that cattle property? And is 100LL available there? (I assume yes, since you're doing this in a Cherokee six already, but at what cost? If you could have an aircraft that would run on regular car diesel and Jet-A, or regular car unleaded, it might make operations a lot simpler.)

And do you need basic IFR for the occasional cloud, or a serious IFR tourer, de-iced and everything?

And what's the terrain in-between? If you were to keep on flying a single and had an engine failure, what would be the chances of survival? Because to be honest, this sounds like a typical job for a C182 with an SMA diesel or something similar to that.

One of the problems with twins is the horrendous maintennce costs. You might find yourself better off sticking with what you currently fly... :suspect:

In a slightly backward country such as Australia http://images.ibsrv.net/ibsrv/res/sr...lies/wink2.gif you are also going to need to consider the ability to service the engine - there may not be that many approved diesel service agents.

As an example the DA42 has its advantages but even in Europe there are places you would not want to develop an engine fault.

"Tecnam are reported to be working on a Rotax 914 turbo version"

This aircraft could already be a bit of game changer in the IR instrcutional market place and if turbo charged and/or FIKI it might be suitabel for twin piston AOC ops.

As Peter says, the Tecnam is fairly useless for touring. A useful load of 400 kg means you'll never be able to carry 4 adults anywhere, indeed 3 with fuel will be a challenge.
140 knots is too slow for a twin IFR tourer. You may not be burning much gas but you are travelling at single engine speeds. And the range is dreadful.
Also the limiting speed for the gear is 90kts. Try flying an approach into any reasonably busy airfield at under 90 knots and I'd take a book to read while your being held.
I'm sure it's a good training aircraft for schools but for hard IFR it's just not suitable.

There are 3 sets of numbers that matter to an aircraft owner:

1) Useful load, so that you have enough capacity to carry your typical load

2) Overall performance, so that the aircraft has the range and speed appropriate for your typical trip and the runway performance necessary to operate from your typical airfield.

3) Total ownership costs. Fuel use is only one part of the equation. A rough but nevertheless surprisingly accurate predictor of costs is when comparing like performance singles and twins double the cost of the single. So for example a Seminole will be twice the total costs of an Arrow and and an Seneca 2/3 will be twice the cost of a Lance/Saratoga for the same miles flown. I would suggest that for a Cherokee six the same equation would roughly apply. Double the money for approximately the same load, range and runway performance.

The Twin Comanche is a very impressive aircraft with very good fuel efficiency and simple and economical 4 cylinder engines. However the cabin is smaller and the payload much less then a Cherokee six and parts are getting harder and more expensive to find. To equal the capability of the Cherokee Six I would say you would have to get an Aztec.

Yikes, missed that one - that's an amazingly low number.

(in comparison the DA42 gear can be extended right up to Vne (= 194 KIAS) and retracted at 156 KIAS - pretty good)

Perhaps a little thirstier but a really lovely machine if you're in Cessna country was the Cessna 310R - not the Q. You'd need to check the log books for undercarriage maintenance on those. It's a weak spot but then it's a six seater and unlikely to have been on a training licence.

I would second the choice for a twin comanche.
You can find them really cheap nowadays. Expect to pay around 80.000 US for a really nice one with low hour engines.
They're great to fly and really give you a lot of speed and joy for 16 GPH @ 160 kts.

I would agree with the BPF and CC. A look at an older "old school" twin such as 310 or Baron could well be a good idea. A nice low hour Baron would be attainable for a surprisingly reasonable sum. If you buy well then any difference in fuel costs can be put aside
Someone once said something to me regarding fuel costs for light aircraft which made a lot of sense. It went along the lines of sorting out all your fixed costs first. Best deal on insurance, within reason keep it where hangarage is reasonable etc etc. Then if you want a twin it shouldn't cost a lot extra per year. I know these should be obvious but I have seen a few people who haven't been on top of all their fixed costs and have been handing over a lot more than necessary.

“Best deal on insurance, within reason keep it where hangarage is reasonable etc etc.”

That might work outside the EU, but most privately owned aircraft which do 100h a year, the fuel cost will be more than the rest of the costs put together (in the EU). Even my Rotax powered machine burning 18.5lph of mogas - fuel costs are 52% of the yearly costs (based on 100hours a year).

Rod1

Most Efficent Twin?
 

It might be this!









Charlie

Most fuel-efficient twin?
 

Probably, though my compatriots won't thank me for saying this, the 787.

I only mention this because the OP hasn't specified his mission in sufficient detail to answer more clearly.

What load?

How far?

Is speed important?

Field performance?

OEI ceiling?

Overwater speed?

...and so on.

(the 787 is quite nice to fly too, as it should be, though I'm sorry they've handled pitch-power couple the way they have and I'm not sure that Boeing have done all they should with some systems; the performance calculation looks like something from the 1980s).

OK, more seriously:

Some Senecas are pretty good all-rounders; avoid those which have been thrashed by flying schools and the V with it's shocking DOW/MTOW. The handling is never better than OK, and at low speed is, in my view, only just reasonably certifiable (hence all the landing accidents).

The Baron is a delight. Do not buy one if you open and read your bank statements because you have to.

If you have a load to carry and want to feel proud, bite the bullet and buy a Navajo.

To join one of the happiest bands of owners I've met, go for the Twin Commanche, but accept that it is a machine which focuses on range, not payload. The owners club is a must.

A GA7 is very nice, albeit slow, but good ones are VERY hard to find.

Avoid all the modern stuff; it's down to a price and a weight, not up to a standard.

If one wants range and efficiency in an "old" design, then look no further than to the Piper Aerostar. Yes, it's known for being a fast rocket (the fastest, in fact), but that also means it's the most efficient. The 700 will do 260kts on 45-50gph. At 205kts, it'll sip 25-30gph. Go down to fast single engine speeds, around 140-150kts, and the Aerostar will probably not drink much more than 15-20 gph (a guess). That's rather impressive. With a standard 165gal, or optional 210gal tank, it's easy to see just how far one could go.

To get efficiency there is only one thing you can do - reduce drag. Aerostars have one of the narrowest cross sections and a very high wing loading, so that's why the have minimal drag.

http://www.adamfrisch.com/images/aerostar.jpg

Although that's the Aerostar's stall speed innit'? ;)

Well, I've seen a Rutan Defiant for sale recently in the UK.

I am surprised that the Cessna 337 has not been mentioned. Though not equal to a Twin Comanche is some regards, it will exceed in a few others...

Lean more. 13 GPH (OK, that might give you 155 kt).

Like the din... ;)

Another devoted Twin Com fan.

Yes, I'm a Twin Comanche fan too, as long as you're not trying to taxi in between high snow banks, or help someone's grandmother get aboard!

MT props make it a real preformer too!

http://i381.photobucket.com/albums/o...g/IMG_4394.jpg

http://i381.photobucket.com/albums/o...g/IMG_4399.jpg

The Tecnam P2006 is a pure training aircraft, not suitable for anything else IMO. Range, speed, operating ceiling and surprisingly poor finish quality wouldn't justify the $450k as a personal aircraft.

A Rotax 914 (i.e. turbo) version of the P2006 wouldn't be that great either because first of all, the 914 got a shorter TBO than the 912S and most importantly, the 914 does not like AVGAS 100LL.

The TwinCo is a great aircraft but that is no secret so used market prices are quite high for such an old bird.

The problem with the C337 is the pilots peripheral vision. When you put the paper bag over your head so nobody can recognize you in such a god-awfully ugly airplane :E, everyone just cuts two eye holes in the front. The problem is you can't see out the side without turning your head, thereby creating a danger of hitting something :ouch:

I completely disagree about the Tecnam. If you want to go from A to B with twin safety at single engine prices, this is the only thing that can do it. Yeah, the DA42, but it's more than twice as expensive to buy and doesn't go any faster. Also, even in places where they don't have Jet A1, you can bet they'll have Mogas at a local gas station. Mogas is available everywhere.

If you're going to GA airfields only, you might get Mogas or they might let you be creative with jerry cans and a taxi but if you fly to a real airport, I don't know of any airport that offers Mogas or would let you bring in your own Mogas (a lot of jerry cans btw). Given that the P2006's endurance isn't great at all and personal aircraft are used for trips to remote places, I still don't think a Rotax 914 equipped P2006 would provide much value.

A twin engine ceiling of 15000ft and a single engine service ceiling of 7000ft isn't even enough to cross the Alps safely. In my view, the P2006's mission capability is that of a low end single.

I would always prefer a used D42 (if you like modern and fuel efficient planes) or one of the old AVGAS guzzlers when it comes to a personal twin.

Mogas may be "available" everywhere but usually only in jerrycans, and the business of transporting jerrycans makes it impractical for serious use. For example my usable tank capacity is 86 USG (325 litres) which would be about 17 jerrycans, each of which is so heavy I can barely lift it and would need a sizeable vehicle to transport them. Also no normal garage would allow that many to be filled - AFAICS.

Very much so; its ceiling is too low. If the ceiling is really 15k, and that (depending on the cert regime) is usually defined as +100fpm climb rate, then you are looking at ~FL130 as the highest practical altitude at say ISA+10 (typical southern European / Alpine summer conditions) and that is below the Eurocontrol MEAs in that region. For example this route has an MEA of FL140 and that is one of the lower ones. (Also that route is too long for it). It would be flyable VFR but only on very calm days when there is no chance of a downdraught.

But I think they know their market. It is FTO training and surveillance.

Re cost of capital, I really think this needs to be disregarded on a private purchase because if you took that into account you would die very rich not having done anything remotely interesting :) What cannot be disregarded is depreciation.