Flight Test

Panther on the prowl

Ian Seager loves this gorgeous new single-seater, in fact he is so impressed that he’s decided to order his own

We love pretty much all aircraft at FLYER. Whether they’re intended to provide a magic carpet ride for family or friends, haul loads out of short rough strips or to earn their living teaching people to fly, we’re big fans of (almost) the lot. But there’s one category of aircraft that brings even bigger smiles to our faces, and that’s the aircraft where the compromises that every designer has to make are made with the sole aim of providing fun for the pilot, and surely the ultimate expression of such a machine has to be the single-seater.

Somehow, news of the Panther’s arrival in the marketplace had passed me by, but happily our features editor, Ed Hicks, as sharp as ever, not only knew about it, but when he found out that it would be exhibiting at the Sebring LSA show in January this year, he emailed Dan and Rachel Weseman – the husband and wife team behind Sport Performance Aviation and the Panther – to try to arrange for me to fly it.

During the show the little red-and-silver Panther was parked on a stand close to the runway to make participation in the daily ‘showcase flyby’ easier, and despite not being in the core of the show, I’d be willing to bet that the SPA stand saw more visitor traffic than any other. It was the best looking aircraft at the show – by far – and every time Dan took off to fly in the showcase, heads were turned skyward thanks to its Corvair engine, its melodic crackle sounding just about perfect amongst the Rotax 912s that dominate the LSA market.

It turned out that arranging a flight at Sebring was going to be a bit of a challenge. Apart from being seriously busy with customers visiting the stand, as Dan put it, “Letting someone with a funny accent who you’ve only just met fly your one and only single-seat prototype aeroplane makes you think a bit.” And who can blame him? We were all being very conservative, Dan and Rachel because they would need their nice shiny aeroplane in one piece for all sorts of reasons, not the least of which was the upcoming Sun ’n Fun show, and me not wanting to be the person who rolled it into a ball. Besides which, I didn’t have the time to remain in Florida to rivet together a replacement, which is what I would have felt compelled to do had it all gone wrong.

We settled on a flight from Haller Airpark rather than Sebring. It’s Dan and Rachel’s home and the Panther’s birthplace. Even that took a couple of attempts, thanks to some less than ideal Florida weather, but late in the afternoon on the last day of a recent US visit we took a rental C182 into Haller’s 2,700ft grass runway.

The Panther’s construction is fairly straightforward. A welded steel structure runs from the seat back to the firewall, has a roll-over bar, points for the engine mount and wing attach fittings, and undercarriage. This is delivered fully-welded and with all of the critical attach points, including fittings for an optional ballistic parachute, in exactly the right place with the aim of making construction both easy and accurate. The aluminium monocoque rear fuselage, which obviously includes the empennage, is attached to the steel structure. The wings are of traditional aluminium spar/rib construction and contain the fuel tanks (a total of 27 usg/102 litres) – and while it is not mandatory, every kit has the provision to include a folding mechanism for the wings. Both at the Sebring show and at Haller, Dan demonstrated a simple one-person fold that took little more than a couple of minutes and ends with the leading-edge of the wing resting on a cushioned tailplane. Obviously this makes for easy storage and cheaper hangarage, and given the Panther is all about good, economic fun, the wing-fold is a big bonus.

Up front, SPA’s prototype is fitted with a Corvair engine, basically an aero conversion of the six-cylinder, horizontally-opposed, air-cooled car engine, which develops about 105hp in this installation. It was a natural choice for the first airframe as SPA has long been involved with Corvair conversions, making parts for an optional fifth crankshaft bearing, amongst other things. However, for now at least it is a bit of an unknown in the UK, and even in the US there are Panther beta builders who are planning to fit alternative engines, so while SPA won’t be able to support every single option known to builderkind, it is planning support for many common options including Lycomings, Continentals and possibly Jabirus, ULPower and even the ubiquitous Rotax.

Comfortable & simple office

Haller Airpark is very much a small aviation community and you get the impression that many of them feel part of the Panther story. On the afternoon of my flight there were quite a few people hanging around; they were looking at the Panther, socialising and generally doing what aviation people do when they get together. Dan decided to take the Panther for a flight, partly to check for any squawks, partly to show me through his overhead aeros routine that he had every confidence in the aeroplane and partly, I imagine, to have one last flight, just in case I messed it up.

I’d spent a fair bit of time reading the pilot notes and talking through various phases of flight with Dan. Of particular note was that the engine turns the prop the other way (just like an Auster or Chipmunk); the Corvair might rich cut with the combination of full carb heat and a sudden application of power; and it doesn’t like negative g, but a re-start in the air is easy. Like any other aeroplane, it’ll float if you are too fast and stall if you are too slow (put down that keyboard, we know about AoA and 1g stall speeds).

The first thing that strikes you when you climb into the Panther is the feeling of space. This is a cockpit that’s been designed for real people, and for the hard of reading – yes, that’s a euphemism for those of us who’d benefit from spending less time at our desks and more at the gym. Both the seat rake and the rudder pedals are adjustable, so it’s easy to get comfortable.

On the left-hand side of the cockpit you’ll find three levers, one for trim, one for the throttle and one for the mixture, plus a plunger-type control that operates the carb heat. Just ahead of the stick is a fuel tank selector (left, off, right) and there are toe-brakes on the rudder pedals. Beside my left leg is a bar for operating the flaps, which are either up, 10 degrees down or fully down.

The panel is beautifully simple and dominated by a Grand Rapids EFIS screen. Other than that there’s a small radio and just four switches, six contact breakers and one start button. Bliss. The only thing I’d do differently would be to replace the fuel valve with one from Andair; it’s not that the current one doesn’t work, more that Andair’s a Brit success story and that it makes very beautiful fuel valves. 

With the five-point harness tightened, it’s time to close and lock the canopy; a lever locks pins into position when pulled backward, which is a bit different to most things I’ve flown. With the canopy closed and locked, I find myself both glad of a little solitude and wishing for some air-conditioning. Right, better get on with it before I melt.

Great handling & visibility

The Corvair engine is very simple to start: master on; both fuel pumps and ignitions on; throttle cracked and starter pushed; and that’s it – all that’s left to do is to wait for up to two minutes for the Grand Rapids AHRS to align.

There’s a short taxi through the soft Florida grass to the runway, power checks are Corvair simple and really only mean checking each ignition system, the carb heat and full and free controls. Lined up and with one stage of flap, the throttle is opened, some left rudder’s needed, the acceleration is brisk and the view over the nose good. After a bit of weaving I’m airborne and climbing away, best rate of climb is 85mph, but Dan had already mentioned that the CHTs might climb a bit, so cleaned up I stuck with a better view and higher airspeed. I guess I was being kind to the cylinders, but selfishly I was also interested in the cockpit cooling airflow through the two eyeball vents and faster meant better meant cooler!

I had a few minutes to myself in the overhead before the camera ship launched, so I took the chance to play around a bit. Compared to the Cessna we’d arrived in, in fact compared to most other aeroplanes, the visibility is superb with great views left, right, forward and up. Handling is also impressive and it doesn’t take long to realise that the Panther is a great-handling aircraft. It’s stable yet responsive and the control in both pitch and roll is really well balanced with just the right light-but-building stick force. The rudder was responsive and powerful, but if I’m honest it was perhaps a bit too light for me, either that or my feet aren’t as delicate as they should be.

The LSA rules call for a max cruise speed of 120kt, so max continuous power is set to deliver that. More rpm means more power and more speed, and the Corvair delivers maximum horsepower at 3,100rpm. Using that setting you’ll get an IAS of around 160mph. As you’d expect for an aeroplane designed for the LSA market, low-speed handling is good and behaviour at the stall in the configurations I tried is impeccable.

Although Dan had flown a bunch of aeros in the overhead, before I took off I’d decided that I’d limit myself to a simple aileron roll if I was feeling happy with the aeroplane – I was only the fifth person to fly the Panther, it was my first flight on type, my aeros are a bit rusty and when it comes to stuff like this I’m a coward rather than a steely-jawed bloke who snacks on broken glass every time he gets peckish. Being happy with the aircraft, I’m glad to report that the aileron roll was fine – the roll rate isn’t spectacularly fast, it’s better than a T67 but probably not quite as fast as something like an RV-8. This one flying example has wings for the LSA market, which have a 23.5ft span, although there’s also a sport version with wings that are two-foot shorter, and while some are being built, none have yet flown, and Dan’s best guess is that the roll rate will improve by about 20%.

All too soon it was time to head back to Haller – being a residential airpark Haller has properties with gardens, hangars and garages that lead to the runway, and there are two tarmac paths running across it at either end. This means that it’s a requirement to make a low approach in order to inspect the runway for people or animals, and to let people know that something’s about to land, so when in Rome… Pulling up from my fast pass, err runway inspection, I realise that although the most hazardous part of the flight is still to come, I’m feeling very comfortable and very at home; the Panther really is a very nice, very simple aeroplane to fly.

I was probably a bit faster than I needed to be on the approach, and even with full flap there was, as predicted, a bit of float, but the Panther’s pretty easy to land, at least on grass and with no wind – think Jodel rather than Extra or an Auster. I taxi back, park in front of Rachel and Dan’s house, and shut down. I know I’m lucky, I get to fly lots of different aircraft. Almost all of them are pretty good, a very small number are average and an even smaller number are exceptional. The Panther, for its handling, good looks, folding wings and $11,500 kit price, is one of the exceptional aeroplanes. As I climb out I ask Dan how nervous he was. “On a scale of 0-10, err about 12.” Me too.

The single-seat market is a funny place, it’s not really dominated by any one type. For the serious aeros fans there’s the Pitts S1 or the Laser, then for real ale-drinking Morris dancers there’s the Tipsy Nipper. The Silence Twister is gorgeous but expensive and the RV-3 is undoubtedly ‘Van’s great’ but it’s probably not an ideal first build. So right now we have a choice between specialist, folksy, expensive or a challenge to build – the Panther’s none of those and that’s why I’m sure it’s going to do very well. It combines delightful handling, good basic aerobatic capability, great looks, spacious comfort, folding wings and what looks like a fairly quick and simple build, with outstanding value.

As I write this, it’s not yet available in the UK, but I’ve got a feeling that will be changing, and I liked it so much that as soon as it’s got the LAA’s approval I’m writing out a cheque for my Panther kit. Right, I’d better start making room in the garage for a workshop, and figure out how I’m going to explain the addition of another aeroplane to the family.

Cougar - fun for two?

Funnily enough, before Dan started work on the Panther he’d already sketched plans for a two-seat tandem taildragger for the LSA market. The Cougar (they do really plan to call it that) will look very similar to the Panther and as well as sharing construction techniques and methods, may also share some of the parts. If SPA can bring a two-seater to market that offers the same handling qualities, fun factor and value for money as the Panther, they’ll doubtless be onto a winner.

As Rachel is keen to point out, the Panther is their priority right now, but once the kit has been optimised and kits are in full production, the Cougar is next up.

Tech Spec

Performance

Maximum cruise 120kt for LSA rules
Stall speed 50kt (58mph)
Take-off distance 1,000ft (304m)
Landing distance 1,200ft (365m)
Load factor +6/-4.5g

Weights & loadings

Max take-off 1,115lb (507kg)
Empty 650 -750lb (295-340kg)
Payload 365-465lb (167-212kg)
Fuel capacity 27usg (102lt)

Dimensions

Wingspan 23ft 6in (7.16m)
Length 19ft (5.8m)
Cabin width 28in (71cm)

Spec

Airframe Aluminium
Engine Corvair 3.0lt (others available)
Propeller Sensenich fixed-pitch wood/composite

Manufacturer

Sport Performance Aviation www.flywithspa.com

Price

Basic kit from tail to firewall $11,500 Basic kit from tail to firewall $11,500 (2014)
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