Click on the photo to see the video.
After weight, speed and range are two important aspects of specification to consider.
First, a short story to illustrate. Many years ago, a group of us were flying from an airfield near the Gold Coast to the annual ‘Natfly’ event – then held at Narromine in New South Wales. It’s about a 4-5 hour flight, depending on your speed. My aircraft would cruise at around 95-100 knots; there were others in new 120-knot hot ships. So it was lots of ‘see you when you get there Pete, we’ll be in the bar’. All that sort of thing. So they were a bit surprised to find me parked and tied down when they arrived, just over 4 hours later… And it all came down to range. My little plane carried almost 120 litres of fuel and still left weight for a passenger and baggage. And there was plenty of reserve fuel for the flight. The speedy aircraft carried much less fuel and for safety had landed about halfway to refuel. So overall, although a slower cruiser, I got there first – a bit hare & tortoise-ish.
However, it isn’t a simple matter of more fuel or more speed…
To go faster you need a sleek aircraft with less drag. How’s that achieved? A slimmer fuselage profile – less space for people, baggage and fuel. A thinner sleeker (and probably smaller) wing – potentially trickier handling and less room for fuel. Possibly a composite airframe, with no exposed rivet heads to slow you down. Lots of aerodynamic work in the engine bay to reduce drag – more expensive, more chance of overheating on a long climb to smooth air or when you’re not cruising flat out?
And it’s no good being able to go fast in still air if you have to back off the speed by 30% (sometimes more) when the air gets rough. Which means the airframe has to be stronger, which means more weight, which means less for people and fuel. It can be a vicious circle of diminishing gains.
To go further, it’s relatively simple: you need more fuel. But more fuel means bigger and/or more tanks, leaving less space for people and bags. It also means the wings can’t be too slim or small as they are potentially needed for fuel. And in light sport aircraft with their maximum 600 kilos take-off weight limit, more fuel invariably means less weight available for people and bags.
As we used to say in marketing: ‘You can either have it fast, or cheap or high quality. But not all three’. So it is with aeroplanes – every manufacturer is trying for that elusive combination of high speed cruise, slow speed safety & handling, high weight carrying capacity and, last but not least, lowest possible cost. Unless you have an almost unlimited wad of cash (then, surely, you wouldn’t be in the light sport market?) you have to choose your own priority requirements and be prepared to compromise on the others.
Next – something you should never compromise: Safety
Written by Dan Johnson (see his aviation blog at ByDanJohnson.com) it concludes that Rotax is by far the world’s biggest aviation engine manufacturer, with well over 50,000 four-stroke and over 120,000 two-stroke aircraft engines delivered to date. As a result, their annual engine sales can be used as a barometer for the recreational/LSA market as a whole, as other manufacturers like Lycoming and Continental are not really players in this market.
Dan makes some interesting remarks around the different proportions of LSA versus GA registrations in the USA in comparison with the rest of the world. In the USA, the GA-LSA ratio is 80-20, while in the rest of the world the ratio is reversed: 20-80 in favour of LSAs. He comments that this is probably because GA is relatively cheap in the USA and perceived to be very expensive elsewhere. (Tell me about it!). Although USA is the biggest single LSA market, nearly twice as many LSAs are actually sold outside the USA.
Other influencing factors in the USA may be that many aircraft service centres are unfamiliar with Rotax engines and some don’t even have access to the metric tools needed on the engine. Contrast that with Europe – and even Australia – where the Rotax is now a familiar engine.
I’m aiming for this to be the first in a series about simple aircraft. The series will be about easy flying in light aircraft, sometimes with nothing but an airspeed indicator, a slip ball, a tachometer, and an oil pressure gauge. These aircraft are all about a love of flying, pure and simple, without the need to get somewhere by a certain time and without the need for all the latest digital gadgets beloved by so many of us pilots.
I’m hoping it will re-kindle that wonder of getting off the ground, maybe just after dawn on a clear winter morning, or taking off into one of those warm, still summer evenings, when the long shadows give such an amazing sense of depth and contrast.
And where else to start but with the Piper J-3 Cub…
The J-3 Cub is thought by many to be the aircraft which personifies the essence of flying: near perfect control harmonisation, the third wheel at the back (where many old-timers say is the only place it should be) and complete simplicity of operation – no flaps and an ‘armstrong’ engine starter (there’s no electrical system). Although flown solo from the rear seat due to centre of gravity requirements, nevertheless, the J-3 Cub is an easy plane to fly…everything happens very slowly. If there is such a thing, the ‘typical’ J-3 is powered by an engine of only 65hp – but remember, this is a very light aircraft, even by today’s standards, and 65hp is plenty enough for all but the heaviest of crew on the hottest of days.
The very first Piper Cub, the J-2, had its origins in 1930 in the Taylor E-2 Cub, manufactured by Taylor Aircraft in Bradford, Pennsylvania. This aircraft, sponsored by William T. Piper, a local industrialist, was intended to be an inexpensive introduction to aviation but the Taylor company went bankrupt within a year and Piper bought the assets, although retaining C. Gilbert Taylor as president and also the company name. From a slow start, Taylor/Piper eventually built about 1,200 J-2 aircraft in the 1930s before a fire at the Bradford factory halted production.
In 1938, the company was re-established as Piper Aircraft, the factory was relocated to Lock Haven, Pennsylvania and the J-3 was born. The J-3 featured, among other changes, a more integrated design of tail fin and a steerable tailwheel. It was originally powered by a 40hp engine and cost about $1,000 – for relevance, the average cost of a new car in USA was around $675 at that time. When the second world war broke out, the J-3 became the military trainer of choice and by the end of 1940, when the USA joined the war, over 3,000 J-3s had been built, powered by a number of different engines, designated by a suffix letter: J-3C (Continental), J-3L (Lycoming), J-3F (Franklin) and so on. At one point during the war, it is estimated that a J-3 was coming off the production line every 20 minutes!
During the late 1930s and 1940s around 20,000 J-3 Cubs were built, many designated as the military ‘L-4’ version. Since then, tens of thousands of Cub variants have been designed and built by Piper, most famously the Super Cub, with powerful 150+hp engines, which give exhilarating performance, albeit at the expense of some of the endearing flight characteristics of the original J-3.
Sadly, in 1994, Piper went into liquidation and they stopped building the Cub. However, the aircraft lives on and various versions of it are now built in the USA both as certified GA aircraft and as Light Sport Aircraft (LSA) by Cubcrafters (in Yakima, Washington state), and American Legend Aircraft (in Sulphur Springs, Texas).
Here are some links to a few of my very favourite Cub videos (click on the names to connect):
The Classic Piper Cub – a short introduction to, and history of, the Piper Cub
Lainey’s first plane ride – a magical short video about a little girl’s first flight – in a J-3 Cub, of course. Reminds me of taking my own grandson, Ollie, for his first flight in my Foxbat about a year ago
The Yellow Piper – by Kristina Olsen, about learning to fly in a boyfriend’s Cub
Golden Wings – just the J-3 taking off, flying and landing
Dreams of Flying – an excerpt from the well-known video ‘One-Six Right’ featuring a J-3 Cub
And finally, if you are thinking of acquiring a J-3 Cub, there are hundreds in the USA. Have a look at Barnstormers.com aircraft for sale – hit the search button near the top of the home page, scroll down the menu on the left and click ‘Piper’ then scroll down and hit ‘J-3 Cub’. There’s usually a reasonable range, from basket cases to newly restored.
Today I went to the e-Go Centre in Cambridgeshire, UK – home of an ultra-modern single seat aircraft – the e-Go Aeroplane. Click here for information in a previous post: e-Go Aeroplanes.
I met CEO, Adrian Hillcoat and Sales & Marketing Manager, David Boughey, seen L-R in the photo here, with the currently dis-assembled e-Go prototype.
We spent 2-3 hours looking around their facility and discussing the technical aspects of their aircraft, testing schedules and production plans, as well as potential interest in Australia.
For testing purposes, the prototype has been fitted with a wonderful array of strain gauges and computerised data logging equipment. There’s nothing that’s not recorded – flight speeds, engine parameters, flight envelope, heights, airframe stresses under different flight conditions, even a complete GPS track of each and every flight. Every time an aspect of the design is changed, it’s checked and tested to ensure the desired improvement is delivered.
Although technically the aircraft fits into the UK ‘deregulated’ class – i.e. single seat with maximum weight, wing loading and stall speed limitations – the aircraft is being finalised to be capable of LSA compliance and maybe even full certification at a later date.
e-Go is aiming for production to be started during the first quarter of 2015 – much of the first year’s production has already been sold.
The aircraft will appeal primarily to the buyer looking to put some extra fun into their flying. Owners will include GA and LSA pilots who already own a more staid bigger aircraft; or perhaps owners of a fast car, motorcycle or boat, who want to add a third dimension to their fun; and even maybe glider pilots, who will find they can ‘thermal’ the aircraft and who will feel instantly at home in the glider-like cockpit.
Although the aircraft is not primarily intended for long cross-country flights, there will be space for an overnight bag behind the seat, as well as other stowage for water, maps and other items in the cockpit. Duration of the aircraft is projected to be around 3½ hours plus reserve, at 90-100 knots, so you could go places if you really want to. However, the primary purpose of the aircraft is to give the weekend flyer a big grin – the test pilot’s partner says his smile after each flight is enough to light up a sizeable town!
Towards the end of the meeting, Adrian, David and I considered for some time a variety of different purchasing options, to make ownership or part ownership a relatively easy and affordable process. There are some interesting possibilities to think about.
Personally, I believe this is one of the more exciting developments in very light aviation in a long while – the e-Go company is well funded, has a wealth of design and technological excellence, and the aircraft itself looks very good – and by all accounts, flies even better.
I think they will have no problem selling every one they can make…….watch this space!
Click here for the e-Go Aeroplane website
Unfortunately, there is no simple answer. However, here are some thoughts to consider when weighing up the pro’s and con’s. Please remember – these comments apply to the Foxbat. Other aircraft can and will have different considerations.
1. The maximum permitted continuous rpm for the Rotax 912 series engine is 5,500, whatever propeller is fitted. We therefore pitch the standard, on-ground adjustable propellers on the Foxbat so they will just reach 5,500 rpm at full power, straight and level at about 1,000 feet amsl. This gives a maximum true airspeed between 95 and 105 knots, depending on the propeller type, the size of the wheels and whether spats are fitted. At this pitch, the prop typically gives around 5,250 rpm at full power on take off and best climb speed of around 60 knots.
2. The maximum power & torque of the standard Rotax 912 carburettor engine is achieved around 5,800 rpm, which you can use for a maximum of 5 minutes at a time. Ideally, you’d use this full power rpm for take-off, and for the first couple of thousand feet of climb if you really need it. Rotax specify a full power take-off rpm of no less than 5,200.
3. Therefore, with the standard prop pitch setting on the Foxbat, although you are within Rotax limits, you are not getting full power from the engine at take-off. Even so, take-offs at maximum weight can still be achieved in 50-100 metres (at sea level), and this setting gives you the best cruise speed.
4. To give a higher cruise speed on the Foxbat, a CS/IFA propeller cannot be set to run any faster than the on-ground adjustable prop. But it could be set to run up to 5,800 rpm on take-off. This will shorten the take-off run in the Foxbat and increase the climb rate. A bit.
So, in summary, a CS/IFA prop on the Foxbat will improve the already impressive take-off performance but will not increase the cruise speed.
BUT…there’s more: there are couple of uses for a CS/IFA prop – other than better climb and/or cruise – which are not often considered.
The first is to use the prop as an air-brake, when you need to descend quickly, by setting it fully fine pitch and engine at idle. The Foxbat is already fairly draggy, so doesn’t pick up speed quickly in a dive. With a fully fine pitched prop, it’s like having a great big parachute holding back the aircraft.
The second use is to allow you to keep the engine warm by using higher rpm at slower airspeeds. For example, a fully fine pitched prop on the Foxbat could allow you to run at 5,500 with an airspeed of only about 65 knots. This may be useful in poor weather when you’re looking for a landing site, or for mustering pilots who need to fly slowly most of the time.
A third use relates more to an emergency. If the worst happens and the engine loses power or stops, by setting the prop fully coarse, you can substantially extend your glide range, as there is less wind resistance on the windmilling or stationary prop.
AND…yet more: there are a couple of major disadvantages to CS/IFA props.
First is the cost. A good CS/IFA prop for a Light Sport Aircraft (LSA) like the Foxbat is going to cost at least A$5,000 more than the standard on-ground adjustable prop and probably more. You won’t get this back in fuel savings for a very long time, if at all.
Additionally, most if not all CS/IFA props weigh considerably more – as much as 10 kgs more, in some cases – than the standard props. All this weight goes right on the nose (affecting weight and balance) and comes straight out of your usable load. This isn’t so much of a problem with the Foxbat’s excellent load carrying capacity but could be on some of the heavier aircraft in the LSA category.
And don’t forget, you need a CS/IFA endorsement on your RA-Aus Pilot Certificate or PPL to legally operate an aircraft with such a prop fitted.
My conclusion – while a CS/IFA prop may have big advantages on a more slippery, faster cruising aircraft, the benefits for the Foxbat are more debatable. If you want to be able to run on the limit for the complete flight envelope (and your pocket can handle it), maybe a CS/IFA prop is worth it. Me? I like the simplicity of the Foxbat and the take-off performance is more than enough for all but the most extreme conditions. So I’m happy with one of the standard props.
What about you?
1. LSAs were originally devised in the early 2000’s in the USA where they were intended to bridge the gap between unlicensed ultralights and fully certified GA aircraft. The objective was to make non-ultralight flying less expensive, through cheaper aircraft and reduced pilot license requirements. Instead of FAA certifying aircraft, the responsibility was shifted to the the manufacturer to confirm their aircraft were compliant with a number of quite rigorous ASTM standards (formerly known as the American Society for Testing and Materials). These standards cover everything from original design through to manufacture and flying characteristics. FAA continues to police the manufacturers through full-blown inspections of their factories and processes to ensure ASTM standards are being met.
2. As of 15 April 2014 there are 134 different approved LSA aircraft available in USA. The number approved in Australia is unknown as neither CASA nor RA-Aus publishes this information.
3. The very first officially approved LSA aircraft in both USA and Australia was the Evektor SportStar Plus. Thus with some pride, Evektor claims to be the ‘Number One LSA’ company. In USA sales terms, they rate at No. 5.
4. The ASTM LSA standards were over-ridden by CASA in Australia in a number of areas. The reasons for this are unclear but rumour has it that some local manufacturers felt some of the standards could not be easily met by their products at the time. The main differences are:
– the USA straight & level, full power, maximum speed limit is 120 knots. There is no maximum speed in Australia
– the USA stall speed at maximum take-off weight (MTOW) must be under 45 knots ‘clean’ – ie no flaps. In Australia it is 45 knots in landing configuration – ie with as much flap as you need.
– the USA allows both glider and banner towing by LSAs. Australia only allows glider towing.
5. LSAs may be factory manufactured – in which case they are known as ‘Special’ or S-LSAs – or built from approved kits – in which case they are known as ‘Experimental’ or E-LSAs. In Australia, E-LSA aircraft registration numbers on RA-Aus aircraft (but not CASA VH- aircraft) are preceded with the letter ‘E’ – for example: E24-8460. Under E-LSA regulations, there is no ‘51%’ rule, so an aircraft can be almost complete, with only a few items for the builder/owner to finish.
6. An LSA aircraft may only be modified from its delivered configuration with the manufacturer’s written approval. This includes adding to or changing instrument types on the panel (including changing the radio type), changing any of the installed equipment, even installing bigger (or smaller) tyres. Contrary to popular belief, a CASR Part 21 engineer (previously known as a CAR 35 engineer) cannot legally approve modifications to an LSA.
7. In Australia, LSAs can be either be VH-registered with CASA or 24-registered with RA-Aus – the aircraft are identical, only the paperwork and pilot license requirements are different.
8. CASA-registered LSAs (but not RA-Aus registered LSAs) can be flown in Night VFR conditions, provided they are fitted with the required Night VFR equipment and the pilot has a night rating or higher.
9. Retractable (‘re-positionable’) landing gear is only permitted for amphibious LSAs . Landplanes must have fixed landing gear.
10. The Aeroprakt A22LS Foxbat is an approved LSA aircraft both in USA and Australia. Customer aircraft are registered both with CASA and RA-Aus. Among them in Australia, there are both amphibious and Night VFR rated aircraft.