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Flight test: Piper PA-30 Twin Comanche

PUBLISHED: 13:16 29 June 2018 | UPDATED: 13:16 29 June 2018

Flight test: Piper Twin Comm

Flight test: Piper Twin Comm

Keith Wilson

Still sprightly at fifty-years-old, the Twin Comanche can give younger pretenders a run for their money | Words Bob Davy | Photos Keith Wilson

The name of this great light twin rather gives the game away. The Piper PA-30 Twin Comanche design started with the single-engined PA-24 Comanche, a laminar-winged rocket which itself was a breakaway from the sturdy but slow aircraft that Piper was famous for at the time−such as the Cub, the Cherokee and the Apache.

Beech had taken the GA world by storm with the Bonanza and Piper genuinely had to raise its game. To keep up, along came the PA-24 in 1958. When the Bonanza begat the twin-engined Travel Air and subsequently the Baron, Piper was inspired to give the PA-24 to Ed Swearingen to re-engineer it as a twin.

The result was an aircraft which could fly faster than the much later Piper Seminole on less horsepower and yet lift more. And despite losing some effective wingspan due to its twin engine installation, the ‘Twin Com’ has only 9.5 inches more span than the single.

Piper’s Twin Com prototype first flew in 1962. It was and is a fantastic little aircraft, able to fly at 160kt below 10,000ft, burning just nine US gallons a side on a combined total of 320hp. Turbo Twin Comanches are particularly fast at altitude, typically cruising at 195 knots at 20,000ft. With speed mods to the wings, fillets and engine nacelles, this figure climbs and 200 knot-plus speeds are readily achievable.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

Despite its success, Piper was out of its comfort zone with the Comanche line, and when a flood destroyed its Lock Haven factory in 1972 the company appears to have used that as an excuse to stop Twin Com production after only just over 2,000 had been built, and its counter-rotating PA-39 development was just getting started, not even a couple of hundred having left the production line.

Certainly when after the big recession in the 1980s and ’90s Piper looked at its existing stable of twin designs with an eye to restarting production it was reckoned that the labour-intensive construction of the Twin Com would result in a price of at least one million dollars per aircraft, dictated by build cost alone. For this reason the much cheaper but less capable Seminole was brought back into production instead.

Today, PA-30s−and especially the small handful of PA-39s remaining−are cherished aircraft with a keen following and strong owner groups, who make a point of using the type’s long legs to arrange fly-ins all over the world.

Laminar wing

Flight test: Piper Twin CommFlight test: Piper Twin Comm

My first experience of the Twin Com was when I did my twin rating on the type in 1985. At the time both the aircraft (G-AVVI and G-AXRO) that I hired were in commercial use as charter aircraft at Southend airport. I remember finding the performance a big leap from the Pipers singles that I had flown.

I listened intently to the stories I was told of the infamous laminar wing: how the aircraft could “fall from the sky” if you flew it too slowly by the seat of your pants without paying attention to the ASI. In aerodynamic terms, up until then Piper had been very much a one-trick pony, using the old Cub aerofoil across its model range.

This kind of wing converts airspeed to lift much more readily than does a laminar aerofoil. (If you wondered why a laminar-winged aircraft cuts through the gusts while the average Piper will have your head impacting the roof, now you know.)

The one big disadvantage with a laminar wing is that its stall is usually much more dramatic than with a traditional aerofoil, such as the Clark Y. I found this out flying into Le Touquet not long after getting my twin rating. I was coming in to land on the now disused south-west runway and had reduced my speed to minimum approach of around eighty−i.e. well below the single engine safety speed of 105mph−because I had already committed to land and the runway was short.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

As I flared I encountered wind shear and the Twin Com really did fall out of the sky. I managed to firewall the throttles to cushion the impact but the landing was hard enough that once I had taxied clear I stopped and got out of the aircraft to examine the main undercarriage to make sure there wasn’t any obvious damage before continuing. I got away with it but the incident left me shaken.

With this experience still lodged in my data bank after all these years I was intrigued to reacquaint myself with the Twin Com. I’m in my fifties now so not as sharp as I was, but I’m experienced on swept-wing jets and various laminar-winged high performance aircraft−so I wasn’t expecting any surprises. Then again you never know, do you?

Owner Mark Hadley is showing me around his immaculate 1967 Twin Com ‘Turbo B’ at North Weald, complete with its beautiful and original blue-and-white paint scheme. (You can tell this one is a ‘B’ because of the extra side windows and the facility for an extra row of seats.)

The first thing that strikes me is its size: so much smaller than the beefy Apache and Aztec, and smaller still than the Seminole trainer, which came later. A Twin Com has forty fewer horsepower and 200lb less MTOW than a Seminole but can propel a similar load considerably faster. No surprise then that it is at least twenty per cent better in every way than the old Apache that it replaced.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

Bigger on the inside

Climbing inside a Twin Com is the aviation equivalent of entering Doctor Who’s Tardis. This toy-like aeroplane reveals itself to have a quite large cabin. It’s a serious machine in every way. Controls, levers and dials are in abundance, sprouting from a deep instrument panel.

The windscreen almost seems like an afterthought and the effect is akin to looking out of a letter box, until you get the seat position just right so that your eye height is half way between bottom and top of the screen.

The next thing I notice are the engines projecting out much farther forward than with many other light twins so that you sit well behind the props. I’d imagine a de Havilland Mosquito must feel a tiny bit like this.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

Once strapped in, the area around the front seats is actually quite roomy. At 44 inches, the cabin is two inches wider than a Baron’s and even the rear seats can be occupied by two adults. Between the seats−a space wide enough for a traditional flight case−there are panels which lift or detach to expose emergency landing gear lowering apparatus, the fuel tank selectors and an archaic fuel sample draining set-up which I remember from my past didn’t work very well.

What you have to do is raise the panel and then pull each drain knob in turn and observe fuel flowing through a clear plastic pipe to see if any water appears. In reality the pipes are usually covered in dust and grime and they also have an annoying habit of working their way loose inside the bottom of the fuselage, which means the drained fuel exits inside the aircraft before finding its way through some or other gap to the outside. Probably not a good idea to avail yourself of the cigarette ashtrays in the cabin.

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The most obviously unusual feature of this cabin, though is at the bottom of the throttle quadrant. Here project two overly-large turbocharger controllers−verniers like the throttle/prop controls of a Cessna−which are used to bring the turbos on line at altitude. And, more importantly, are used to wind them offline during a descent (if you don’t you will overboost the engines).

Out there on the wing tips are the optional 15 US gal tip tanks, which increase the total fuel capacity to 120 US gal and−because of the cantilever effect of weight distribution−also increase MTOW by 125 lb to 3,725 lb. Dividing 120 gallons by 18 (cruise fuel consumption) equals 6.6 hours, providing a 1,100nm range. And for the turbo version it’s 1,300nm-plus! As I said, a serious machine in every way.

The starters, mags, fuel pumps and generators are a line of toggle switches at the base of the instrument panel. Engine starting is classic ‘fuel-injected Lycoming’: crack the throttles open, hit the fuel pumps until you see an indication of fuel pressure, pull the mixtures to lean, make sure the generators are switched off, crank each engine in turn after switching on the mags and, as it fires into life, bring the mixture levers up to full rich.

After start check oil pressure is rising and bring the generators on line. Very straightforward it may be, but there is always a sense of occasion starting up a twin. As a twenty-something, I remember thinking that I had finally ‘arrived’ when I soloed one of these aircraft and that same rush is still with me more than thirty years later.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

I release the brakes with the locking chrome T handle in the panel under the control column and allow the Twin Com to roll forward under idle power before checking the toe brakes. There is quite a bit of weight on the nosewheel due to those projecting engines but the steering is actually light and progressive.

A little care has to be taken about the geometry of the toe brakes−they are too upright for my taste. Due to a running injury, my right foot can’t flex less than about seventy degrees to my lower leg, and its all too easy taxi with the brakes deployed inadvertently. I slide my feet down a little to stop myself. We are a long way under our MTOW so the aircraft feels sprightly.

The engine run up and pre-takeoff checks are quite involved and I opt to use my old commercial pilot checklist from the ’80s which has been typed-out and photocopied to death. But if it was good enough for the commercial pilots of the time then it’s good enough for me.

I advance the throttles fully and the aircraft accelerates well. The previously heavy stabilator comes alive in the prop wash and I hold the column neutral as we gather speed. At seventy knots I raise the nose and the aircraft unsticks abruptly.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

I apply the toe brakes and then raise the undercarriage with the tiny selector to the left of the panel. The ASI is pegged at 1,500fpm before I bring the throttles and props back to 25/25 then sync the props by pulling and pushing one prop lever back and forth to locate which way slows down the ‘wah wah wah’ noise−then keep going until the noise stops completely.

From the ground the Twin Com sounds quite noisy because of its unusual exhaust pipes but in the cockpit there isn’t as much noise as in a comparable single.

As we break out of the circuit and head for the Essex coast I start to get a feel for the aircraft again after my thirty-plus years’ gap. It feels like a larger aircraft than it is. The stabilator is firm but correct for this type of aeroplane, roll control is lively and with high hysteresis−or roll inertia−due to the wing-mounted engines.

If you come from high-wing singles this will take some getting used to and you will find yourself seesawing in roll until you settle down. The Twin Com is actually lovely to hand-fly and I don’t use the autopilot at all during our hour long flight. Formation flying with the camera ship is pretty straightforward although it is easy to become unsighted during the break away manoeuvres due to all the hardware obscuring the view.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

The turbo controllers are used as follows: when the desired manifold pressure can no longer be obtained by advancing the throttles in a climb, you turn to the verniers and start winding them in until manifold pressure is restored. By 20,000 feet they will be all the way in and you will be flying at 195 knots or better.

In the descent the opposite is the best way to proceed; rather than abruptly disengaging the turbos, just leave the throttles fully forward and progressively wind the turbo verniers out until they are all the way back, then slowly retard the throttles. Yes it requires a bit of work but then this is a fifty-year-old aeroplane.

Engine-out performance

Next we try flying on a single engine. I get owner Mark to feather our left engine as I keep control of the aircraft and allow the camera ship to fly alongside. The rudder is powerful and I can easily hold the out of trim forces with one engine shut down, although the use of rudder trim and a little bit of aileron trim means I can actually fly hands off. (Why aileron trim? Because a wing without the benefit of prop wash creates less lift, even a laminar one.)

Flight test: Piper Twin CommFlight test: Piper Twin Comm

Slow speed flying is also predictable, as is the abrupt g break you get, clean or dirty. Add power and the g break is accompanied by a wing drop of as much as 45 degrees. To stop it, just unload the wing with a shove of forward column and that’s that. All laminar-winged aircraft that I have flown are the same as this.

On the approach the Twin Com behaves itself just so long as you remember to adhere to the correct speeds. I am having no problems descending, slowing down, and fitting into slower circuit traffic at North Weald.

The aircraft is not particularly trim sensitive and the old fashioned, roof-mounted trim wheel feels instinctive as I progressively wind it backwards for nose-up trim as we slow down and then introduce progressive flap, then undercarriage down (no trim change). I fly final at 105mph, remembering the old ‘blue line’ safety speed from my training many years before, then back to ninety, and eighty as I cross the fence.

Throttles closed at the same time as, but not before (laminar wing, remember) a small flare and we land on the main wheels in a flat attitude, quickly followed by the nosewheel. Some owners pump the main wheel oleos to the full extension to avoid this but then the ride on the ground suffers. Running down along the hard runway at North Weald feels the same as the ride you get in a ’50s British sports car.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

I looked at the US market for used aircraft and PA-30s were all in the US$45,000-120,000 price bracket. That’s pretty wide but it reflects the cost of replacing two engines and two propellers, in addition to the usual variations in condition and equipment.

I couldn’t find a single PA-39 for sale and that’s situation normal: no one seems to know what they sell for, so I suppose the answer is “a lot”. A large (6ft 4in and 18st) friend of mine has been looking for a twin for some time to commute 600nm at a go and was looking at Barons and Cessna 310s which have twice the burning/running costs of a Twin Com.

He thought the PA-30 too small but I think he might well change his mind when I arrange for a flight in one in the next few weeks.

Flight test: Piper Twin CommFlight test: Piper Twin Comm

Piper PA-30 Twin Comanche ‘Turbo B’ specs

Dimensions

Length: 7.67m

Height: 2.49m

Wing Span: 11.20m

Wing area: 16.54sq m

Weights and loadings

Empty weight: 1,092kg

Max AUW: 1,690kg

Useful load: 598kg

Wing loading: 102.18kg/sq m

Power loading: 6.78 kg/kw

Fuel capacity: 455 lit

Performance

Vne: 208kt

Cruise: 194kt @ 75%

Stall (gear & flaps down): 60kt

Climb rate: 1,400 fpm

Service ceiling: 30,000ft

Engines

Two 160hp Lycoming TIO-320-C1A engines

Propellers

Hartzell two-blade metal variable-pitch propellers

Manufacturer

Piper Aircraft Corporation, Lock Haven

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