As I sit here on the eve of another long haul international business trip to the mother continent, I can’t help but daydream about ways to do it in my own plane. If you’ve spent a lifetime at godforsaken airline hubs, smelled the stained and stale old wall-to-wall-carpets they always come with, suffered through colonic irrigations by blue gloved TSA agents, had your luggage sent to Katmandu, had a customs officer interrogate you every time you come back to what’s been your home country for years, constantly been downgraded to middle seats between obese people that snore or very small children – you know what I mean. Or faced yet another one of the US carriers old 757’s with ash trays still in the arm rest (how long has there been a smoking ban on airlines? 25+ years? That’s how long those seats have been in there). I wish I could just jump into my own ride and be done with it. And for about the same money and about the same time door to door. Inevitably, my mind drifts off into theoretical ways of solving this problem for humankind.
What this world needs is a super light, small 1 or 2 place aircraft, pressurised, de-iced, with great range that can fly high and get good TAS for not much fuel burn.
I remember Mike Arnolds old AR-5 he built over 30 years ago. 213mph on 2-stroke Rotax 65hp. And I think – why haven’t we come a bit further?
Or Kevin Eldrege’s Relentless – a Nemesis NXT – that does 380kts full speed. Or 325kts on 16gal/hr according to his website. That’s great economy for that speed.
Such a looker that Nemesis NXT.
It is obvious that high speed and good fuel economy are related. I know this from my Aerostar (which was the main reason I bought it). Now, a twin will never be as economical as a single, but at full economy cruise according to the POH mine will do 184kts @25000ft for 20.4gal/hr. That’s about as good as it will get in a twin. But it is obvious that real fuel economy, the one that will rival any commercially bought airline ticket can not be achieved at high speeds. It’s one or the other. Good thing is it’s in the same plane, so you can either chose to go fast and expensive, or slow and cheap.
I was blown away by this article in AOPA. This guy has a highly modified Vari-EZ that gets 100mpg. It does 190 KTAS on 3,5gal/hr! He flew from LA to Oshkosh (1500nm) on 30 gals of fuel. Now, that’s real economy. You couldn’t find an airline ticket for even twice that amount. Even with European prices for fuel, this would beat the airlines every day.
We have much work to do, but at least these articles show that it is possible.
Think about the reliability you want. To get reliability equivalent to one turbine engine, you want at least two but much better three piston engines. These will then bring so much drag that a reasonable airspeed costs an unreasonable volume of fuel.
Yes, for extreme fuel economy a twin is not the way forward. There might be a spot where you can get a twin to be a good balance between reliability and economy, and the Tecnam P2006T and the TwinStars seem to be inhabiting this area at the time. But they’re still nowhere near being an economic alternative to commercial air travel. To achieve that we need to reduce drag at all costs and not carry any excessive weight. We need a small front area, so thin wings and a small cross section is key. This is not always conducive to benign slow speed handling, but that’s the price you pay. Like in the example of the Vari-EZ in previous link.
I just like the idea of an aircraft that can provide transportation for me and maybe one more person for half the price of an airline ticket. Or for less than driving.
Physics and economics can’t be beaten by dreams, I’m afraid. (Spent too much time earning degrees in aerospace engineering to believe in miracle stories told on the internet…)
You can get that sort of economy – although not to airline passenger cost – with a turbine. But the entry prices are very high. Pressurisation and FIKI would add a lot to the cost with weight and complexity.
Turbines are great, but if you want to maximise fuel economy, then they’re probably not the right choice. How much does your Jetprop burn up high at economy cruise?
Turns out that the numbers in the previous article on the Vari-EZ was a little off. He gets 45mpg at 207mph, which is still stellar performance (like a Prius). The 100mpg must have been at a much slower speed. Here’s a link to the economy race he won:
You can get that sort of economy…
With “economy” I mainly referred to monetary issues which are mainly dominated by purchase cost. A small single- or two seater can have a fuel consumption as low as it wants – if the engine alone costs a million Euros/Dollars/Pounds the thing can never be an economical aeroplane.
I agree with what next. As some of that analysis we did earlier in the year showed, nm/l or nm/gallon don’d change as much as you think. question is usually how fast do you want to get there. That is exponentially proportional to purchase cost.
Adam, a Vari-Eze has benign low speed handling – Rutan chose the canard configuration for that very reason. A friend who flies competitive aerobatics had one as a kid when they were being built in volume, tried everything to find its issues but while he was able to make it ‘depart’, that took some serious wacko stuff. At the time this guy was working his way through an undergraduate AE program as an aerobatic display pilot, so I imagine he tried pretty hard 
Another friend and I once flew a 300 mile leg in a Comanche 180, in loose formation with an O-200 powered Vari-Eze. He was literally flying circles around us to stay in the same general area, and when we got there he took 6 or 8 gallons or something, and the Comanche 18 gallons. There’s not much that will go 200 mph in comfort on 100 HP, especially that you can buy for $25-30K
The limitations of the Vari-Eze (other than baggage capacity) come into play on short runways. On take-off they have limited pitch control until reaching a speed well over minimum flying speed, so one technique used is to bounce the nose up and down by pumping the canard-mounted elevator. At the top of the bounce, the canard reaches a higher AoA and if the plane has accelerated enough the nose will stay up, once its up, and the plane will fly off.
I’m heading off on a 10 hr commercial flight myself tonight, so I empathize. For me its several times a year, and the airline travel is the worst part. Its a lot cheaper than it used to be, but unpleasant and prices are rising.
Yep, the Vari-EZ seems to have great economy. That new little Pipistrel Panthera is rumoured to be able to cruise on 10gal/hr at 200kts carrying four people. That’s 23mpg, which ain’t bad. The best I could see in the Aerostar is around 10mpg. But still some ways to go to get to this Vari-EZ guys 45mpg.
Jason – I wasn’t being glib at all and I hope I didn’t come across that way. I’m genuinely interested: what fuel burn do you get at best economy up high?
