Fixed-pitch props are fine, but learning to fly with a constant-speed propeller opens avenues to lots of new aircraft.
Peter Steele set himself the challenge…
17 March 2022
I have been flying for 15 years and have spent that time blatting about the skies in the usual 172s and PA28s. So when the chance to fly something larger and faster arose I realised it could change my flying forever. Instead of being content with the throttle and mixture controls, I would learn to use the ‘big blue one’ – the control for a constant-speed prop.
I guess the next step would usually be to fly a 200hp Piper Arrow, but at Fowlmere, we have a 1989 Piper Saratoga with a 300hp engine, six seats, and a three-blade prop. I’d admired it from a distance while flying the Archer IIIs. It’s fixed gear, so one less difference to worry about, but would it be a step too far?
It’s an impressive aircraft, with a wingspan of 37ft, a nine-litre flat-six fuel-injected engine, containing 300 horses driving a three-blade Hartzell constant-speed prop. Cruising at 130kt, 102 US gallon tanks, air conditioning, stormscope, GTN 750, six seats and two baggage compartments make it a capable tourer. Other features include the large front windscreen (unlike the letter box of the Archer III), plus it’s wide enough so that your co-pilot doesn’t have to breathe in as you breathe out – all making it very comfortable over longer distances.
My instructor for this enterprise is Derick Gunning, who has amassed 10,000 hours in 30 years of flying, and is a very experienced tutor on Saratogas.
My lessons follow the same format: a briefing explaining the key learning points for the flight, the flight itself and a debrief at the end.
The first thing Derick explains is the difference between a variable-pitch prop and constant-speed prop. The blade angle on a variable-pitch prop is manually controlled by a gear connected to the control lever and they tend to be found on older aircraft. The constant-speed prop on the Saratoga is hydraulically operated using engine oil, which keeps the engine at the selected rpm.
The advantages of a constant-speed unit over the fixed-pitch prop, found on many GA aircraft, include optimised performance in each stage of flight – a fixed-pitch prop is only at its optimum blade angle on take-off. Like the gears in a car, fine pitch (low gear/high rpm) is used for take-off and a coarser pitch (high gear/lower rpm) is used for cruising.
Another difference with the Saratoga would be having to measure power using the manifold pressure gauge instead of the rpm gauge, as on the Archer. This one would catch me out more than once – more on that later.
Sitting in the cockpit for the first time is a nice experience. The Saratoga’s four-foot wide cockpit makes the Archer feel cramped. The switches for master/alternator, fuel pump, anti-collision lights/strobes, recognition lights, and pitot heat are to my left on a box on the side wall. Changing tanks is easier too, the lever is on the central pedestal near the floor, instead of next to my left ankle as per the Archer. The view over the long nose is surprisingly good, as is the view out generally. The combined manifold pressure/fuel flow gauge and rpm gauge are low down below and to the right of the main panel, not the best location really, and in later versions of the Saratoga they are high up in the centre panel.
Derick then explains the starting procedure: throttle one inch open, mixture fully lean, master and fuel pump on, mixture to fully rich, watch the fuel flow needle increase and stabilise, mixture to lean again, throttle reduce to half an inch, call ‘clear prop’, and operate the starter. She fires up instantly, needing no adjustment on the throttle, to settle down at 1,200rpm. I check the starter warning light and oil pressure. All OK. It sounds complicated but I get used to it quite quickly.
Taxying is easy, just like an Archer, and we roll up to the Bravo hold at Fowlmere’s 700-metre grass runway.
Power checks are straightforward, the only differences to the Archer are cycling the prop three times (not less than 1,500rpm), changing to alternate air (which we don’t do on grass) and checking the fuel flow. Pre take-off checks are done here as well and they’re straightforward. I’ve lowered two stages of flap and I feel the small electric flap switch is a bit awkward.
However, I like the PA28 ‘handbrake lever’ as it’s difficult to get it wrong.
Derick tells me to expect to use right rudder on the ground roll and in the climb. I advance the power to 2,000rpm, check Ts and Ps and then release the brakes, adding full power over four seconds. The surge forward surprises me and I really do need right rudder. Weight off the nose at 60kt, hauling back on the yoke at 75kt, and climbing away, aiming for 85kt.
“The prop is already at 2,500rpm so just leave it there. Keep an eye on the manifold pressure, you’ll need an extra inch for every 1,000ft of altitude”
Then I hit the brakes to stop the wheels spinning, reduce flap by one stage at 200ft – don’t forget the right rudder – and, WOW, this thing climbs! Flaps up at 300ft, climb at 100kt – with 1,000fpm climb rate showing on the vertical speed indicator.
Derick says: “More right rudder. More, more, you have to counteract yaw.”
I’ll need to get used to that.
“Now you can reduce to climb power.”
Reduce? Not used to that either.
“A reduction in power is from the left, so reduce the power to 25 inches.”
I move the throttle until 25 inches shows on the gauge.
“Watch out for lag, the needle is still dropping.”
I compensate, now I’m flying too slowly and the balance ball is showing me I need yet more right rudder.
“The prop is already at 2,500rpm so just leave it there. Watch the manifold pressure, you’ll need an extra inch for every 1,000ft of altitude. Climb to 2,000ft.”
The manifold pressure has dropped again, I need to add more, oops I’m at 1,700ft already, lower the nose, don’t let her climb past 2,000ft.
“It’s very easy to overshoot your assigned altitude in this aircraft, you have to be ready for it. Get back on heading.”
I’m 20° off course! So much to think about.
“OK, now we need to set cruise power, which will be 23 inches and 2,300rpm. Remember a reduction is from the left so reduce the throttle first.”
Throttle to 23, then prop lever to 2,300… prop very sensitive… I’d forgotten about the lag on the throttle, it’s dropped to 18, I move it back to 23.
“Now reduce the mixture, watch the fuel flow gauge. We are burning 25 gallons an hour. We usually fill this aeroplane no more than 70 gallons for weight and balance. Reduce to 15 gallons an hour.”
We practise turns, starting with medium-level ones before moving onto steep turns. She’s not very demanding in turns, very little rudder input required, but she is very pitch sensitive, reminding me of a Grumman Tiger I used to fly 10 years ago.
“Now we’ll climb to 3,500ft. An increase in power is from the right. Think of a car’s accelerator pedal being on the right. Mixture rich, 2,500rpm, set 25 inches manifold pressure.”
Mixture to rich, prop to 2500, power to 25 inches. That throttle lag catches me out again. We climb, and this time I’ve added the MP gauge to my scan. Sure enough I have to add that extra inch of manifold pressure as we climb.
“Let’s practise cruising. Set 23 inches, 2,300rpm. We should see 120kt.”
OK, which way is that. Think of the car’s accelerator pedal. Increase from right, decrease from left. 23/2300 set – 120kt. I’ve forgotten the mixture, still burning 25 gallons per hour, so I reduce to 15.
“This is a great cruising machine, so set 25/2300 and mixture 17USG.”
I have to re-trim but we are now skimming along at 130kt, very pitch sensitive now.
“Let’s try the autopilot, it’s a KFC150. Press and hold the black CWS button until the yellow flight director appears on the AI. Now set your heading bug, press ALT, HDG, autopilot engage.”
She’s flying herself now, a lot better than I can.
“OK, we’ll turn back towards Royston, reduce back to 23/2300 15 gallons.”
I’d set ROYST waypoint in the GTN 750 earlier and call it up now and turn towards it, using the heading bug.
“Disconnect the autopilot using the red button. There are two ways of descending. First, put the nose down, minimum of 500fpm. You can increase your speed into the yellow arc in smooth air.”
I do, and the faster we go the more lift we generate so I add more trim – 150kt now, just below the start of the yellow arc.
“If the air isn’t smooth, just reduce power to 20 inches.”
Done, not so quick now.
“You need to be at Fowlmere’s circuit height of 800ft at Royston. Don’t forget you’ll have to turn earlier as you cover more ground than in an Archer.”
I’ve just made it. I call Fowlmere for rejoin, change to QFE, follow the road and railway that run north-east from Royston. I’ve missed them, not turning early enough. Circuit speed is around 90kt in the Archer, 110kt in the heavier and larger Saratoga. I circle round and try again. Follow the landmarks, road bears to the right, call downwind when abeam the runway, not before.
“Now downwind checks: brakes pressure, undercarriage down… the gear is fixed but we always add it for when you fly a retractable… mixture rich, fuel pump on, flaps 10° – knocks 10kt off, instruments check, hatches and harnesses secure.”
There’s nobody else in the circuit but I’m careful turning base leg as Duxford’s traffic heads over the village of Thriplow to my left. I’ve left it a bit late again – still think I’m flying an Archer – but clear of the village.
“Reduce power to 15 inches and second stage of flap. You should get 85kt.”
I pull the throttle back to 15 inches.
“You’re using the rpm gauge, not the manifold pressure gauge.”
Oops! I’ve set 1,500rpm instead of 15 inches. Sort it out.
Descending now, 400fpm. Turn finals, allow for the wind from the left, Derek has called finals for me.
“Now PUFA checks, prop full forward, undercarriage down, flaps full. Altimeter cross-check.”
Full flaps giving me 75kt.
“Yes, it’s a numbers machine. If you set it up right it’ll do all the work for you. You will need a trickle of power all the way down, you can’t glide down like an Archer.”
The sink rate with full flaps is much greater than an Archer, I’m controlling the descent using power. Over the hedge at 75kt, power to idle, flaring and landing quite smoothly with no hint of drama.
After taxying and parking it’s time for the debrief… I need to anticipate earlier with this aircraft. It’s faster and heavier than an Archer. I’ll have to add the manifold pressure to my scan and get used to changing it quickly, anticipating the lag and remembering to add an inch of pressure for every 1,000ft of altitude and subtract a corresponding amount when descending. Remember: descending under power will increase the air over the wings and therefore the lift, which will reduce the descent rate. I need to descend at a minimum of 500fpm and monitor it.
My lessons that followed continued the same pattern. Derick likes to keep the interval between training sessions as short as possible – I think I benefitted from the intensity – well, that is, when the weather didn’t interfere.
My circuits gradually improved but it didn’t take much to overload me and I missed the crucial PUFA check on finals during one circuit. Attempting Practice Forced Landings proved interesting. I had problems reaching the selected field, which improved once I’d worked out the Saratoga glides without flap at roughly the same rate as an Archer with full flap. Adding full flap to the Saratoga is like descending in a turbo lift.
Derick also drummed into me the emergency drills routine, which I now rehearse as soon as I sit in any aircraft. I thought I knew them, but clearly I didn’t. We dealt with alternator failure (reduce load, check circuit breakers, cycle alternator off and on, then consider options), smoke in cockpit (master off, heater off, floor vents open), prop overspeed (prop and throttle reduce, oil pressure check, if low pressure engine failure could be imminent), plus a host of others I’ve now committed to memory.
We also spent a lesson on circuits. Derick briefed me before the flight that the book figure for the approach is 95kt, but in his view that was much too high, so normal approaches are flown over the hedge at 75kt, with short field at 70kt, especially when Fowlmere’s 700m runway has had recent rain.
We flew normal 75kt approaches, flapless (85kt), glide approaches and short field landings at 70kt – I enjoyed the last one so much we backtracked to the runway, took off and did another one.
In total I had five lessons over two weeks. The total flying time was 4 hours 20 minutes, plus taxying time, briefings and debriefs.
I was a little apprehensive about flying something with so much more power, weight and size than I’m used to, but I needn’t have been. Derick introduced extra learning points once I had mastered the previous ones, so I never felt out of my depth.
The human brain’s learning retention is poor. After one hour people retain less than half the information presented, after one day we forget more than 70% of what was taught and after six days we forget 75% of training. How do we ever learn anything? Never having been blessed with the best of memories, I use my own system to help retention.
I have a small camera (a Drift Ghost X) stuck on the left window, looking into the cockpit. The Drift also takes an external microphone which I simply wedge into the ear cup of my headset. The video and audio are good enough to see the instruments and view out. After reviewing the footage I write notes which I send to Derick. He adds his bits and I read them before the next lesson. I also practise ‘visualisation’ techniques, normally on my morning walk, rehearsing all the stages of flight from departure to landing. This way I can combat my ageing brain’s faulty uptake. It works for me… maybe it’ll work for you!
As pilots we are always learning, whenever and whatever we fly. If you feel you are getting stale, why not try a new challenge? I’ll consider myself on a green ‘P ’plate for the next 10 hours. I’m lucky to have two friends both with considerable experience on complex types (one has owned two Saratogas). I can learn from their wealth of experience on every flight, whether as P1, P2 or a rear seat passenger enjoying the air-con and cup holders. Believe me, whichever seat you find yourself in, the ‘Toga’ truly is a lovely, lovely aeroplane to fly!