By Rod Douglas 

How much fun can one man have trying to sort out the pick of thoroughbreds that grace the sky? In my case I can only describe it as an obscene amount of fun. But before I tell you about it, the aircraft that created it and why it’s a little obscene, I should tell you why I’m writing this article.

Ok, so for those regular readers that are smart enough to pick up Aviator every month because it is the most beautiful, freshest and most unashamedly passionate magazine about Australian flying that graces the newsagent shelves, the aircraft you’ll read about today aren’t new. With the exception of the Cirrus SR22 Turbo, I’ve covered all in detailed articles over the past few months. The SR22  G3 has been worked over fully as well and the turbo is just a simply a standard SR22 with an STC’d dual Tornado Alley turbo strapped on the standard engine to create a turbo normalized TNIO-550 N. No. This article is about what happens to pilots who are willing to well and truly slip the surly bonds by slaying one of the great sacred cows of Australia aviation.

The fact of the matter is that Australia is the only major GA aircraft market in the world where normally aspirated aircraft outsell their turbo brethren. It doesn’t matter whether we are talking the venerable 206 Stationair or the sleek Cessna 400, whenever airframe manufactures get around to slapping a turbo into their airframes they begin to sell more heavy breathers and in volume. In a lot of ways it’s no different to what happens when an avionics upgrade becomes available. When Columbia was responsible for the 350 and 400, they decided one day to offer the G1000 in a very smart installation with a ‘readypad’. From that day forth not a single additional aircraft was built with the perfectly adequate Avidyne Flightmax installation.

Cirrus has just announced a USD$48,000 option for the Cirrus Perspective by Garmin. The installation of a manufacturer specific , fully integrated avionics suite offers 35% bigger screens than the G1000 and promises to be a big hit with owners with the majority of new Cirrus’ being ordered with the option. First delivery was due June 6th, the day I was due to fly the SR22 Turbo. It’s the often unexpected, but always fast, response that we’ve come to expect from Cirrus, who has made an art form of being fast followers who seek to sit safely behind the bleeding edge of innovation.

And it’s obvious but true. Turbo charging, or turbo normalizing, as two of our three competitors choose to apply the technology in their installations, is all about adding technology to the power plant to create greater speed, altitude and efficiency to already well proven airframes, pushing the envelope to give pilots greater utility and choice.

So, let me introduce our contestants in this battle for the hearts, minds and pocketbooks of the most pragmatic and best trained of Australia’s piston business pilots.

Firstly we have the crowned speed king. The inimitable Mooney Acclaim ‘S’. With a claimed top speed of 242 knots, a speed previously reserved for large pressurised turbines, this speed demon is a build out of a 62 year old airframe that proves the adage that if you get it right to start with why change it, just evolve it. With a 280 bhp twin turbo normalized TSIO550N installation it  has been derated for a long and successful life and proves the adage that if you want to go really fast you’d better tuck your wheels, (and anything else than can be), in.

Our next contender is the newly renamed Cessna 400. With a deep lineage back to a family of absolute kit built speedsters, this composite built, slick and smart aircraft is an application of Lance Neibauer’s belief that great aerodynamics make for beautiful planes. Until the release of the Acclaim, the C400 had held the world’s fastest production single title from the day of its release at 235 knots with the wheels hanging out. To be fair, I’ve never seen better than 230 kts while I’ve been at the controls but either way that is really trucking along. The big 310 hp installation of the Continental TSIO 550 delivers a superb installation that runs cool and is proving resilient in a fleet that now numbers  700.

Finally, the SR22 Turbo. This aircraft is the only machine in this contest that is actually simply a technology upgrade on the normally aspirated sister ship that started it all. Typically manufacturers have simply taken a certified and proven turbo charged version of the appropriate power plant, then worked hard to recertify an appropriately modified airframe to deal with subtle but important changes that are required for high altitude flight.

Cirrus took a different path choosing to simply add a STC (supplementary type certification) to the current certification and bolt on a Turbo Alley twin turbo and dual intercooler package to turbo-normalise the Continental  IO550. As we will see there are negatives plus a few potentially strong positives to this simple but effective approach to dealing with a competitive problem. One of the really strong outcomes is an aircraft that consistently outperforms book figures at almost every level. With a book promised top speed of 219 knots it was a delight to see 220 knots appearing on the PFD at FL250.

So, here are the statistics. In the USA the turbo charged powered aircraft within the airframe families typically outsell their normally aspirated brethren by a factor of two to one. Since the SR22 Turbo has been released, 70% of the build has been turbos.

They simply don’t make it down under. Interestingly this trend is showing at least some sign of abating with Cirrus currently holding orders for four turbo charged SR22’s against three normally aspirated aircraft and both Mooney and Cessna sending turbo charged demonstrators down under to show their wares.

There has, in the past, been good reason why pragmatic Australian pilots have avoided turbo charged aircraft. The principal behind turbo charging is pretty simple. Introducing an exhaust gas powered turbine that spins at very high rpm to pressurise the intake air through a forced induction compressor makes a lot of sense if you simply want to get more performance out of an engine because it allows the engine to continue to produce the same horse power at high altitude as is possible at sea level.  In the thinner air at altitude it allows aircraft to dramatically improve their performance and in the case of the Cirrus the same airframe with the same engine burning slightly more fuel will give a 35 knot increase in the true airspeed between a normally aspirated aircraft at 10,000 and the turbo charged aircraft at 25,000 ft.

Not too long ago this magical speed increase came at a cost. Turbo charged aircraft of years gone by used engines that effectively over-boosted the engine to provide high levels of performance.  In these aircraft it was not unusual to see manifold pressures of 36 – 42 inches which is well above the ambient pressures encountered at sea level of around 30 inches. This over-boost introduced new stresses to the engine and required careful management by pilots. The turbo chargers also introduced complexity, weight and, in particular, very high rotational speeds (between 20,000 and 100,000 rpm) which require sophisticated lubrication systems and very clean oil to ensure longevity.  Naturally, pressurising intake air increased the temperature which then needs to be managed and, if not properly managed, shortens engine life. Early turbo charged engines were unreliable and complex and in a country as big as Australia and lacking in the maintence infrastructure to support the engines, many Australian LAME’s and pilots decided that they simply weren’t worth the effort.

The world has changed when it comes to turbos. The new breed of turbo normalised engines have been designed from the ground up to answer most of these concerns. Sure, the engines still weigh more but their performance more than makes up for it and, in the Cessna 400, the certification max takeoff weight is up 200 lbs over the normally aspirated sibling giving a helpful increase in load carrying capacity. This isn’t true for either the Cirrus, who are using the normally aspirated type certificate or Mooney who need to reduce the horsepower available from 310 hp to 280 hp, (with some added advantages it must be said), in the turbo because of the size of the tail which limits the power available at altitude due to rudder authority.

Effectively they perform exactly as a normally aspirated engine would on the ground, with the benefits of the turbos only kicking in as they maintain ambient pressures (and therefore the capacity to climb at 100% power), all the way up through the lower flight levels.  Granted, all three of these engines start to run out of puff once you’re through 20,000 feet but, when you’re still climbing at better than 800 ft per minute all the way to the certified ceiling of FL250, you’d hardly call it panting.

In addition, the provision of dual intercoolers on all three engines means that the previous issues with high temperatures are gone. All three installations run cool and there are simply no engine management complications in any phase of flight. In fact, in the Cirrus once you’ve reached cruise it’s as simple as setting 2500 rpm and 17.5 gals of fuel flow at every level and watch the miles vanish behind you. With stable fuel flows all the way down there are no shock cooling issues and the only thing you need to be mindful of is the rapidly approach yellow arc when you push the nose down.

These innovations have meant that the Mooney and the Cirrus have 2000 hour TBO’s just like the normally aspirated versions and, while the fleet is young, there is no reason to think the reliability of these big six bangers won’t match the amazing reliability that is being seen in the Continental IO-550’s that has become the standard for the high performance four place rockets that have revolutionised personally flown business flight.

Of course the amazing speeds available to these aircraft come at a cost. They are simply significantly more expensive to buy. That said, anyone who has decided that they wanted a bit more performance out of their Mercedes or BMW get the pleasure of paying the significantly higher freight associated with choosing from the AMG or ‘M’ series product. In our case the difference is that you can’t buy a higher speed limit with those speedsters.

 When you normalise the equipment list of these three speedsters the narrow price band tells you just how competitive the aircraft market actually is. To demonstrate this I’ve ‘normalised’ all three aircraft into top of the line comparatively equipped aircraft, with the only missing link being the exclusion of speed brakes for the Cirrus, an option that is not available and probably not needed.

The low price solution is the also the slowest of the aircraft, with the Cirrus costing USD$619,015 and delivering 219 Knots at FL250. To be fair you can get into a basic (but definitely adequate) SR22 Turbo for around USD$450,000. It won’t have any bells or whistles, excludes air-conditioning and oxygen (and seriously why would you buy a turbo and not put oxygen in it), and you won’t have TAWS or TCAS.

Contrast that with the Cessna approach which is to have one price (USD$620,000) which includes everything including a couple of Bose headsets but excluding TKS.  The ‘normalised’ product has a price of USD$620,000 once you add the TKS anti ice, which is not certified for known icing conditions, and is a USD$20,000 option. Apples for apples, the Cirrus has a USD$20,000 price advantage for similar equipment levels.

The most expensive yet fleet of foot is the fastest of these speedsters with the Mooney Acclaim ‘S’ at USD$649,700. Price point is obviously critical in this market, with the Mooney priced fairly fully equipped at $599,500, but that excludes air-conditioning and anti ice however, the Mooney is the only offering with a certified known ice TKS option available.

To this you need to add delivery, which is a significant impost. Cirrus actually uses Australia as its Asian reassembly base and you can get a factory new, zero time aircraft in Australia with a delivery package that costs USD$21,995 on the Australian register. For the Mooney or the Cessna your brand new aircraft will arrive with delivery hours on it. Some buyers will see this as an advantage as most of the squawks should have been shaken out on the delivery flight across the Pacific.

A word on anti-ice. When I lived in the US in the early 90’s I spent a lot of time flying aircraft with anti-ice. When I returned to Australia I started to realise how few piston powered aircraft were equipped with anti-ice. Now in a country with the amazing weather we have that’s quite understandable. So when I got into the Mooney TLS that I flew a few years ago I was ambivalent about the TKS system that it was equipped with. It’s a funny thing when it comes to technology. Once you have the technology, you often find yourself using it. Turbo charged aircraft are made to go high, the higher you go the colder it is and if there is moisture around suddenly ice becomes an issue.

While I had the TLS I was fortunate that I never had to cancel a sector no matter what the weather. That can be contrasted with the eight flights that I’ve had to cancel this year alone while flying a normally aspirated Cirrus.

To be fair it was a few years ago and we were still in the midst of drought. Australian weather has a particular pattern to it. Typically wet weather, the set-in kind, tops out around 10,000 feet. On those days a turbo will burst out of the clag into a truly beautiful day of flying under the bright blue skies and in the uncluttered flight levels of the mid teens. A canula provides oxygen and the ride is smooth and fast. In the Acclaim you will see 220 knots, the Cessna will give you 210 knots and the Cirrus a smidge over 200. I don’t care who you are, flying above the clouds is more relaxed and more pleasurable than the unknown of being buried in them.

If you plough through 10,000 and the clag is still solid there is a fair chance that you’re going to have to climb into the oxygen mask territory above FL180 to break out. Except in the far south, it’s unusual to see much in the way of icing below 10,000. It’s those days when you don’t break out that it’s nice to have the back up of the TKS system. Temperatures are starting to become extreme cold and any moisture can quickly become an icing adventure. I can only remember one flight in the TLS when I climbed all the way to FL250 and didn’t break out. PIREP’s from the airliners around confirmed that the tops on that particular day were at FL300. While I didn’t get into the blue I had a pleasant flight at FL250 well above the turbulence layer which topped out about FL180.

While I only used the TKS system four times that I can remember, it delivered the confidence that in air where there was any visible moisture I could deal with any icing that was encountered, while still being able to take the precautions that are required in any icing situation to change levels. Of course the rule when it comes to ice is, ‘if in doubt put some solid ground beneath the airplane’. I became a convert of the TKS which doesn’t suffer from the degradation that plagues de-ice boots.

It’s a simple weeping wing systems that covers the wing in a glycol mixture. While glycol can be a corrosion factor for metal aircraft, the risk is minimised with the quality of anti corrosion treatment that modern aircraft receive, and it is simply not a concern for the composite airframes of the Cessna and Cirrus. The system is a simple two pump installation that pumps the anti-ice solution through a titanium leading edge that is perforated with thousands of microscopic holes. The controls are simple with a low flow and high flow position switch and the only real maintence is to service the pumps. TKS gives pilots a solid and safe margin when the weather looks a little marginal.

Which brings me to the issue of supplemental oxygen. Because turbo charged aircraft are rare in Australia, there are many pilots how have never dealt with the issue associated with oxygen. This contrasts with the US where the terrain and severe weather are far more demanding. With 70% of aircraft coming off the line in the States as turbo’s, oxygen is just part of the curriculum.

So why do we need supplemental oxygen? It’s a simple fact that the atmosphere becomes less dense at altitude and the human body is simply less efficient at extracting and transporting oxygen. The partial pressure of oxygen at sea level is 159 mmHG but drops by half at FL180. The proportion of oxygen remains stable at 21% but the capacity of our lungs to extract it and use it effectively drops dramatically.

Without enough oxygen we experience hypoxia, with symptoms like confusion, vertigo, hot flushes, tingling in the extremities and headaches. Allowed to run too far it can result in unconsciousness and even death.

 The symptoms and susceptibility to hypoxia varies from person to person and the only way to really know how you’ll respond is to explore it safely in a hyperbaric chamber which can safely simulate the effects of altitude and therefore hypoxia. I was fortunate enough to do a high altitude course at the Marine Corps Base Camp Pendelton, near San Diego when I lived there many years ago. I’m not aware of a facility that allows pilots to explore this effect in Australia but there are many medical facilities that use hyperbaric chambers for the treatment of illness in Australia.

To give an example of the effects I’ve included a chart of the time it takes for an average adult to succumb to the effects of hypoxia.

Altitude (ft.) TUC
18,000	20 minutes
22,000	10 minutes
25,000	3–5 minutes
30,000	1–2 minutes
35,000	30–60 seconds
40,000	15–20 seconds

The rules relating to supplemental oxygen use are clear. CASA takes a much more conservative view than the FAA and requires oxygen use for all flight over 10,000 feet. The FAA advises that supplemental oxygen use is required for all flight between 12,500 and 14,000 feet for periods of over 30 minutes and requires crew members to use oxygen for all flights over 14,000 feet and for passengers to use it for all flight over 15,000 feet.

There are two basic delivery methods for oxygen – a cannula or a mask. All of our high flying thoroughbreds have installed oxygen as a matter of course. For altitudes below FL180 the most efficient way of using oxygen is a cannula which injects oxygen directly into the user’s nostrils. The direct injection is very efficient and significantly reduces the oxygen use per minute. As with all things aviation in this land, getting oxygen refills in Australia can be very time consuming and expensive so the efficient use of oxygen is always a positive.

Above FL180 a full face mask is required. Wearing a full face mask is not the most comfortable way to fly but it is bearable. Many masks come with a built in microphone which can make you sound like Darth Vader during radio transmissions so for Star Wars buff that might be a plus! The reality is that most pilots are willing to give up the last 10 knots of speed for the comfort and ease of only having to wear a cannula and turbos often operate in the completely uncluttered airways between about FL150 and FL180: well above the weather and far faster and more efficient than their normally aspirated sisters.

One of the other considerations of flying turbos and one of the arguments against them by stuck in the mud Australian pilots without experience in them, is that the climb to altitude time, and stronger winds of the higher levels offset the benefits. My experience is that this is simply not true. Flying a turbo well simply requires better planning. It doesn’t matter what you’re flying, there is a best altitude to fly at. On short hops it’s never very high and a turbo flown the same way you would fly a normally aspirated will give you roughly the same outcome. Maybe a little faster; maybe a little more fuel.

On long hops the equation changes. What the turbos really deliver is choices. At altitude the winds are stronger. If they are going your way climb up into them and use them to dramatically cut your time and fuel cost. I remember a particularly memorable flight from Melbourne to Brisbane in the TLS when everything went my way.  Being willing to wear a mask saw me climb to FL220 above a 15,000 overcast and then see ground speeds of up to 315 knots. It wasn’t consistent the whole way but it was my fastest leg and saw me on the ground in 2 hours 20 minutes.

 On the other hand if the winds are going the wrong way, choose the same altitude that you would in a normally aspirated aircraft and get to altitude faster and then get on with slugging it out into the headwinds. If the weather is bleak, climb above it. You might be going a little slower above it than if you stayed out of the winds down low but it’s always a better flight when the sky above you is blue and the sea of white that is a solid overcast is below you.

When it comes to turbo’s one thing is absolutely true. They’re a great, expensive, go fast option for someone who flies because it makes sense to do so. This is the world of the business man pilot, not the recreational aviator. They need to strap themselves into a machine that can compete on block times against the airlines. All these turbo’s can do that. From my house in the mountains behind the Gold Coast to the RACV Club in Melbourne where I stay was always quicker in the TLS than having to deal with the airlines. I got to leave when I wanted to and come home when I wanted. I enjoyed the absolute freedom of it.

The ultimate truth is it makes absolutely no difference which of these amazing turbos was sitting on the ramp waiting for me, I’d be delighted. If you haven’t taken the time to get out and fly one of these machines then declare yourself to one of these manufacturers and then go experience how the modern turbo can make a difference. The only thing that would put a bigger smile on my face was to change the whole game and find a TBM 850 or Pilatus PC12 with my name on it on the tarmac.