Showing posts with label flight-test. Show all posts
Showing posts with label flight-test. Show all posts

Wednesday, September 9, 2009

The Love of my life - Storm Century 5XL


Well not actually the love of my life...that's reserved for a beautiful woman. But if there's an aircraft above all others then this is it. This aircraft is why you need a hangar with room for two: one spot for the Zlin Savage Classic and one for the Century 5XL. That way you can happily fool around on little tiny strips and riverbeds in the Classic and then travel long distances at 125 knots in comfort with the 5XL. What could make a pilot happier?
Stormaircraft srl is based in Sabaudia, Italy. They've been building aircraft for 20 years or more. They have two main lines of aircraft - the Century (used to be called the Storm) which is low wing, all metal and the Rally high wing, composite.
The Century 5XL is the big daddy of them all. In Italy it is flown in 2+2 configuration - 2 small seats behind the front seats to hold the children. In Australia it flies as an LSA with a MTOW of 600kg and a large baggage area behind the seats. Baggage capacity is 75kg. For an LSA the 5XL is a big aircraft. It's 40cm longer than the standard Century and the wings are longer as well. The outcome is an aircraft that has the capacity to do a genuine 120 knots indicated at sea level and true out in the high 120s at 5,000'. Combine that with a fairly benign stall around 35 knots and you have an aircraft that's fast but easily manageable.
Getting in is easy - climb onto the wing root - avoiding the flaps and standing on the designated area, put your inboard leg straight across and onto the place it lives on the cockpit floor. Then rest on the cockpit side whilst you move your inboard hand down onto the structural bar visible between the seats, bring your outboard leg onto the cockpit floor and slide in.
This is a big persons' aircraft. The seats only adjust in rake - if you are taller you can rake the seat back, if shorter then make it more upright. However at their standard setting they accommodate from around 5' 2" to 6' 5" with a cushion if you are at the lower end of that range. The rudder pedals have extensions so that you can shorten the distance to your feet. Shoulder room is great. The throttle and choke are on the centre console between the seats, as are the brakes, the fuel taps, the Hobbs and the headset jacks. Behind the seats is a massive cargo space, you could fit just about anything imaginable - including golf sticks. Just make sure you obey the 75kg limit.
The instrument panel is divided into 3 with the primary flight instruments to the left, comms in the centre - along with the prop controller if fitted, and the engine instruments to the right. Visibility is excellent, you are sitting right over the spar and you can see through an arc of over 270 degrees horizontally.
Unlike some LSA aircraft the 5XL seems like a "big" aircraft, however it's very agile on the ground and has a very tight turning circle - even without the optional toe brakes. The main gear is a set of solid aluminium legs and the nose gear is on an arm with bungees.
The standard engine is a Rotax 912ULS and this aircraft has the performance to warrant a variable pitch prop. The engine installation is very clean with lots of room between the engine and firewall. Access is through a pair of hinge up doors down either side of the cowling.
Sitting at the end of the strip the view is great and as you open the throttle the all-flying stabilator comes to life in your hand (fixed horizontal stabiliser is also available). The aircraft accelerates very quickly and is not at all busy. You need a little right rudder, but not much. First stage flaps are used for takeoff. As you approach 40 knots you gently lift the nosewheel off. This is where you'll likely get your first surprise: the 5XL has extremely light control feel in all axes and the controls are very sensitive. This is a very responsive aircraft and it will punish over-controlling. Climb out is at 60 knots with a climb rate around 1000fpm. The deck angle isn't as steep as many LSAs and visibility is good. Cruise climb is in the 70-90 knot range.
Turns require very little rudder and the roll rate is very impressive. If you want to do your fighter emulation then this is the aircraft. Va is 90 knots and needs to be respected given the roll rates that can be achieved. The aircraft is easily manageable in the turn with very little back pressure required. Stalls are pretty benign, a single finger on the stick is all that is necessary. As the aircraft slows it remains very stable, at the approach of the stall you get a very slight buffet and the break is very benign with wing drop basically absent. Stall speed is as low as 35 knots depending on configuration.
The 5XL comes into its own in the cruise. Set up and going somewhere TAS of high 120s knots is achievable at 5,000'. The aircraft really eats up the miles and is incredibly stable compared to some other LSAs. It's a great aircraft for going somewhere. Just remember to wear your sunhat and sunnies - it can get bright under the big bubble canopy. There's 100 litres of usable fuel and the burn averages around 18 lph. So that gives an endurance of around 4.75 hours plus ample reserves. At 120 knots that's a still air distance of 570nm plus reserves. Nice going.
Returning to the circuit the biggest issue is getting the 5XL slowed down. Vfe for first stage is 85 knots and for full flaps it's 75 knots. Downwind is flown at around 90-100 knots, approaching base leg you go full fine on the prop and this really helps to slow the aircraft; then as you turn base you slow the aircraft further and take first stage flaps. The flaps are electric and on presets so it's one flick of the button for first stage. The aircraft feels very controllable and manageable once the prop is in fine pitch and the flaps are out.
Many LSA aircraft don't present a stable platform for the pilot. They seem to be in constant motion - they are light and have little inertia. The 5XL is a much more stable platform than most. This makes the landing phase easier than many expect. Ideally you select full flaps as you turn final and then it's just a matter of holding the aim point and maintaining an approach speed of 60 knots. Over the fence at 55-60 knots and then into the flair. The speed will fall to around 40 knots (if you're watching!!) as you settle. Everything is very stable and manageable.
The POH lists takeoff roll on an ISA day at SL, nil wind and a sealed strip as 110 metres at MTOW. For the same conditions and 32 degrees flap you get a landing distance of 160 metres. Both of those are about right. Neither of those distances are super short but they are real distances and in line with the type of aircraft. The aircraft is very much at home on everything from sealed strips, to grass, dirt and gravel.
Just as a side note the POH for the 5XL is a comprehensive document, particularly in the area of performance data. Many POHs for LSA aircraft are nothing like so comprehensive.
If you want an aircraft that allows you to travel long distances at good speeds with big loads of gear then this is an aircraft you should seriously look at. It's also a real pilots' aircraft - it will bring a smile to the face of anyone who really loves flying.

Tuesday, September 1, 2009

Tecnam P92 Echo Super - Brief Review


The first thing you need to know is that I've got a real soft spot in my heart for the Tecnam P92 Echo Super. It's a great little aircraft, fun to fly, predictable, simple and robust.
But first the movie: A couple of disclaimers - no Tecnams were hurt in the making of that movie, and the "mate" of mine who created the little sound effect and the flash had it wrong! Despite appearances there was no sideloading on that wheel - the aircraft just pivoted sweetly on the right main and settled like it always does. That movie was taken during a spot landing competition and no I didn't win!! Thanks Ben for a great video.
So let's talk about the basics: made in Italy by Costruzione Aeronautiche Tecnam. Many of you will know the people behind Tecnam - at least by their history. These are the same people who built the Partenavia. The P92 Echo dates from 1992, the Super is the version with the Rotax 912ULS, not to be confused with the Echo S which is another thing entirely.
The first thing that you notice when handling the P92 is that there's nowhere to hang on to it - the only place you can pull and push on is the base of the prop. Everything else - the struts, the leading edges - are all too lightweight to cope with any handling. Construction is aluminium. The all-flying tail surfaces are fabric covered. Access to the engine is simple with two catches on either side allowing you to hinge up the sides of the cowling - like an old car bonnet. The usual Rotax stuff - check the oil and make sure you burp it first, check the coolant, check the exhaust-retaining springs, look for oil and coolant leaks and make sure all the plug leads are in place and you're good to go.
To get in you back up to the open door, bend backwards as if to do the limbo and slide your head inside, then lift your backside onto the seat and swing your inboard leg under the stick and you're in. Make sure you've put the seat right back first. Now I'm here to tell you that you can get two burly blokes into this aircraft - 6' and 6'5" totalling about 220kg. But you have to be good friends. The luggage compartment is behind the seat and is limited to 20kg - at or about 20kg you notice the aircraft becoming very light in pitch control so I think that's a real limit.
Adjust your seat, ignition switches on and turn the key with the throttle fully closed. She should start immediately. It it's cold you'll need some choke but she should still start immediately.
This aircraft gets off the ground pretty smartly. If you work on it you can be in ground effect in under 100 metres and she will be genuinely flying and ready to climb in 200 metres on a good day. The deck angle is steep in the climb - Vy is 60 knots and Vx about 50-55 knots. You should see climb rates around 1000fpm at Vy. Flaps are on a little switch like a paddle - just like its big brothers. There are no preselects so you have to watch the indicator. First stage for take off is 15 degrees. Full flap is 40 degrees or thereabouts.
Prolonged climbs at Vy on an Australian summer day are not recommended. You will overheat the engine. So I usually opt for a cruise climb of 70-80 knots maybe even 85 knots on a hot day. This will give you 5-700 fpm and keep things out of the danger zone.
The P92 is not a fighter and has none of the features of a fighter - and that includes control loads and displacements. The controls have a reasonably light force required and a reasonably long throw. This gets lighter and longer at very slow speeds. Control forces are reasonably well harmonised and there are no suprises.
These aircraft fly with a MTOW of 544kg in Australia. At MTOW the stall comes at about 40-42 knots clean, power off. No surprises, some buffet and very little wing drop. In approach config - say 3,000rpm and full flaps - you get quite a steep deck angle at the stall and you get quite some wing drop - really all pretty tame but it's there. Stall in that config is lower at around 35 knots.
Like many of these sort of aircraft the cruise attitude results in great forward visibility with a markedly nose-low appearance. Genuine cruise is around 105 knots - if you flight plan for that you won't be far wrong. Comfort for longer trips is not bad, but if you're big it's not great either. Setting up the seat is really important - you need it as far back as you can get it and still be able to get decent control deflection - otherwise your legs will be up close to the underside of the panel and it's all a bit tight.
The tanks hold 90 litres (optionally) and with a burn of around 18 litres per hour that gives more endurance than most pilots would have in an aircraft this size.
In the circuit, downwind is flown at around 80-90 knots. The aircraft is slowed below 67 knots (Vfe first stage) during base turn and then more flap is added progressively. Full flaps are limited to 55 knots. Normal approach speed is 60 knots so you have a very small margin at flaps 1 between your approach speed and Vfe. The aircraft is nice and stable though and the view of your target is brilliant. Many times in a crosswind I've run down final looking out of the passenger door window at my aiming point. The aircraft is lightweight and has a low wing loading so it moves around a lot. You have to control it very actively during the landing phase especially in gusty conditions or substantial crosswinds. From memory demonstrated crosswind is of the order of 18 knots.
As you saw in the movie it handles side slips really well. With full flaps and a decent side slip you can come in very steeply with descent rates of around 2,000fpm if you are game. Gravel and dirt strips are equally no trouble. The main gear is pretty robust but you need to treat the nose gear with some respect.
If you want a recreational aircraft that's simple and robust then you should look at the P92. Only her designer, Professore Pascale, could love her looks but she certainly gets the job done. In addition the cockpit seems reasonably protected. I've seen one that spun in from around 100 feet. The pilot survived and the cockpit didn't look as though it had lost much of its capacity!

Monday, July 13, 2009

Zlin Savage Classic - First Impressions



I flew the Classic a week or two ago - it's a copy of the old Piper Cub.

The one pictured was a photo I took in Italy, the one I flew was in Australia. They were initially designed in Italy I believe and are now manufactured by Zlin in the Czech Republic. In Australia this has been called the Savage Cub but it is officially the Savage Classic.

They are sold as a Light Sport Aircraft in Australia. MTOW in LSA config is 560kg which gave about 263kg of useful load.

The aircraft is powered by the Rotax 912ULS and has a Woodcomp wood grain style prop.

The first impression is of a very, very well constructed and finished aircraft that's great fun to fly. It's very simple - a small, well laid out panel, with an XCom radio slung under the edge of the panel.

Stick is central, throttle is to the left, just where your arm/hand fall. Below that towards floor level is the flap lever it's the old "handbrake" style. It requires a little effort to pull flaps on, but the biggest issue for me was being able to reach it. To quote the man at the clothes shop (Henry Bucks for the Melbournians) I have "a long back, short arms and a fat neck". So I found that when the seat was all the way back - which I needed - I had to loosen my left shoulder strap in order to be able to (just) reach the flap lever.

At middle height on the left and back beside the seat is the trim - a toothed quadrant with a lever on it. Pull the lever towards you, pull or push to set and then let it go and it engages with the teeth and stays where you put it. Trim was quite aggressive - one notch at normal cruise made a big difference.

I'm a novice tail wheel pilot so ground handling was an initial challenge. However visibility is very good and after a while it all began to fall into place. The toe brakes are very effective.

Once at the end of the runway it was simply a case of feeding in power, gently picking up the tail and we were flying. I have no idea at what speed - my eyes were fixed on the end of the runway - but I would guess at something between thirty and forty knots. Acceleration was very quick at close to MTOW. First stage flaps were used for take off and Vfe is 60 knots for first stage and 50 knots for full flaps.

Climb after flap retraction was 60 knots and about 850fpm. The nose was sitting just below the horizon and the fun was really starting. This aircraft translates every action to the seat of your pants. Great fun to fly.

Levelling off the first thing that takes some getting used to is the very low nose attitude for S&L. The horizon is well up the screen by the time you are settled into your 85 knot cruise at 4900rpm or so.

Slow flight simply required increasing back pressure until finally the Classic stopped flying with the needle hovering somewhere between 20 and 25 knots. This aircraft was equipped with VGs and they are tremendously effective. I think that the speed was pretty accurate and not the result of positional error at the high AOA.

Wing drop was virtually non-existent and buffet was similarly all but absent. The aircraft is very well behaved at the stall but not telling you too much either.

Turns require a little rudder and very little back pressure for even moderately steep turns. Again the tendency is to climb until you get used to the low nose attitude. Visibility is great with the centre section of the wing having a perspex panel.

Returning to the field the aircraft was remarkably loathe to lose height and we used a couple of moderate descending turns to soak up some height. The Cub showed no sign of wanting to drop its nose or tighten the turn - all very placid.

It was in the circuit that the aircraft showed its true colours. It is docile, highly predictable and well behaved. Approaching base turn we cut the throttle and as the needle dropped past 60 knots we put out first stage flaps. Trim fairly far back - and now the trim is much less sensitive - and the aircraft sat solid as a rock at 60 knots. Easy to manage and not at all busy.

Indeed the one thing that I found unusual was that there was no sense that this was a draggy aircraft - this despite the various struts and bracing wires. It didn't require heaps of height or power to keep it flying.

Turning final we slowed to 50 knots and got full flaps out. Trim almost right back and again the aircraft is highly stable. However there was no sense of high sink rate - unlike a Tecnam in this configuration.

Over the threshold round out, throttle closed and just keep coming back on the stick. My first landing - with some encouragement from the back seat - was an absolute greaser of a three pointer. And that's the only landing I'm telling about!!

Again I have no idea about the speed I landed but the aircraft was easily managed on roll out with little dabs of rudder to keep it tracking. The one thing that got me on a couple of my landings was the fact that you are actually sitting quite high up. I kept thinking the ground was further away than it actually was.

I had the very strong impression that this is an aircraft that would really respond when you wanted to squeeze it into a little, rough strip somewhere. Even on a first flight I felt like I was really communicating with and being communicated to by the aircraft. Just the kind of thing that would inspire confidence if you are near the limits.

Overall first flight impressions: A simple aircraft that's really nicely built and finished. You could have a very great deal of fun in this aircraft. It reminded me so much of the very simple aircraft of the past. No fancy instrument panels, everything simple and manual. An absolute joy to fly.

I'll have one to sit in the hangar alongside the long distance cruiser that flies 40 knots faster. That really is the only downside - unless you count not being able to see your significant other whilst you are flying along.

This is the manufacturer's site: Zlin Savage Classic