Flight test YAK 52 from approx 1993
Picture this: one and one third tons of Russian hardware is diving down to a picturesque airfield and levelling off at 10 feet AGL, the ASI nudging 260mph. At the end of the runway the aeroplane pulls up into the vertical, zoom-climbing through 1,500 feet. As it climbs an effortless 360 degree vertical roll is initiated, followed by a pull off the top into inverted flight. It is the sort of flying that most private pilots can only dream of. Well, I’ve been there, seen it, done it, bought the T-shirt. But before you get jealous take note. You do not have to be rich to go there, see it and do it too. Yak 52’s are now available for hire and purchase at extremely low prices.
In the UK £35,000 buys a nearly new Porsche 911, a good de Havilland Chipmunk, a fair Pitts S2, and a grotty Christen Eagle. It also buys a mint condition, factory overhauled, 360hp military trainer with similar running costs.
US$100 buys an hour’s experience in a Formula Ford racing car, a flight in a reasonable Cessna 150 or a slightly tarnished Cherokee. It also buys a one hour aerobatic less in a Yak 52 with a Dosaff-trained Russian aerobatic instructor.
FLYER was privileged to cast an eagle eye over two YAK 52’s. The green one is owned by Arthur Tyler and Arenair, the English connection of the Skytrace Aerobatic School based in Smolensk. After taking tuition at Skytrace, UK PPL’s will soon be able to hire this aeroplane at Halfpenny Green near Birmingham, The grey one is owned by Mark Jefferies of YAK UK, England’s premier YAK 52 imported. The two aircraft are virtually identical and immaculate, and this flight test report can be transposed onto either example.
The YAK 52 is a BIG aeroplane when compared to the typical Cessna and Piper singles parked on a UK ramp, demure when compared to the beefier Harvard. Mark Jefferies’ battleship grey colour scheme is relevant to the marque because that’s the way it is – a great flying battleship of an aeroplane. Arenair’s green paint scheme is equally impressive because it reminds you of the YAK 52’s lineage: it is a Russian military trainer still in production.
The YAK 52’s main structure is of metal tube with a thick metal skin. The control surfaces are fabric-covered to reduce deflection inertia. The aircraft is covered with mushroom rivets – no high tech flush-riveting on this aeroplane. With 100-200hp up front kiss goodbye to the cruise speed. With 360hp up front the YAK 52 would have an effective cruise speed with a fuel bowser still attached to it. The Ivchenko M-14 P powerplant is a 9 cylinder, single row radial also seen on the front of the YAK 55, Sukhoi 26 and Sukhoi 29. The “paddle” at the front is an agricultural, two-blade, variable pitch affair though a much more efficient, three-blade propeller is an option. These items sell for $3,000 and $12,000 respectively. The radial gills that keep the engine at its best temperature are manually operated from the front cockpit. The oil cooler house underneath the fuselage is also manually controlled. In Yak tradition the ’52 uses pneumatics for engine starting, flap, gear and brake operation. The air reservoir is good for 12 start attempts before it needs re-charging. The aircraft is fitted with a compressor to re-charge the bottle after the engine starts.
The undercarriage looks ungainly and hideous. The Russians build their undercarriages immensely strong and don’t give a damn for appearance. I have it on good authority that the gear will support a plane with three times the YAK 52’s weight. Snow skis are a serious option. With the undercarriage left in the ‘up’ position it still remains partially exposed. The idea is to minimise damage in the event of a wheels-up landing. For a dead stick landing in a ’52 the standard drill is to leave the gear retracted. The book says that this is to flatten the descent profile. Incredibly the brakes remain useable with the gear up.
Climbing up to the cockpit needs a knee on the wing followed by the other leg whilst hanging onto a canopy rail. An anti-skid walking strip lies along the wing adjacent to the fuselage. In Russia it is not unusual to seen an engineer walking beyond the strip and out to the YAK 52’s wingtip along the line of the wing spar. The spar itself is visible inside the cockpit, lying across the floor to the rear of the front seat. Removed from the aeroplane the spar would not look out of place with a few railway sleepers under it and a locomotive on top. The cockpit itself is large, spacious and tres militaire. Low-time PPL’s will inevitably be intimidated by their first sight of the large quantity of instrumentation and engine controls, but the layout is well-designed and logical. The Russians use metric units for aviation and it will take most pilots a while to get fully used to an ASI calibrated in KMH, an altimeter in Metres, VSI in Metres/second etc. A few more foibles for the unwary:
- The RPM gauge is calibrated in per cent of maximum rather than RPM to mimic the jets that military students would be flying after the YAK.
- The artificial horizon works upside down. The top half of the ball is brown, the bottom half is blue. A climbing attitude is shown by the aeroplane figure moving beneath the horizon reference line, as if in a dive. Vice versa for a dive attitude. What a nightmare. The good news is that the horizon will not topple during aerobatics. Mark Jefferies uses it for the 45 degree pitch attitude used during a Cuban Eight, both inverted and upright that it.
- The rear cockpit has a bank of controls to deliberately fail certain systems in the front cockpit. An absolutely brilliant idea if you want to teach failures ‘hands on’. Needless to say, I am told that the CAA is not at all happy with this and that the switches will have to go for UK-certified YAK 52’s.
- The undercarriage gear lever is a pneumatic control: it returns to a central, neutral position when not required. To move the gear up select the gear lever up until you get a ‘three reds’ indication then return to neutral. For gear down select the lever down until ‘three greens’ and then to neutral once more. In the air the system operates so smoothly, without the usual clanks bangs and air noise associated with less sturdy types, that Mark Jefferies is installing a bell to alert him in case he attempts to land ‘gear up’.
- The sound of the pneumatics at work are quite a surprise if you are not used to them. The brakes are operated by a lever mounted on the joy stick and when it is squeezed the noise is like a bus or a lorry coming to a halt.
When climbing into either of the YAK’s cockpits one is immediately impressed by their size and spaciousness. This is in every way a military, aerobatic flying machine and the controls are placed to maximise the muscle that you can exert upon them. If you are a pilot of average height the stick top will be at roughly the same height as you sternum (front centre of rib cage) and with the rudders in their foremost adjustment your knees will be bent approximately 30 degrees from the vertical. Full rudder deflection will give a straight leg on that side. The rudder pedals themselves are twice as far apart as those of a Cessna 150. For trouser, skirt and kilt wearers alike, it is time to trade up to a flying suit and boots.
The throttle and associated RPM control fall easily to hand on the left cockpit wall. The big throttle has separate switches for intercom and outside TX. A friction lever is positioned to the inside of the throttle lever. The front cockpit has an additional quadrant to the right, housing levers to control the engine cooling gills and oil cooler plus an associated lock lever.
Inexplicably these controls, plus the engine manifold gauge, are not duplicated in the rear cockpit. I can only assume that during early training flights Russian instructors must sit in the front, unless or until they are happy that the student will be able to operate the extra controls unsupervised. For my flights with Mark Jefferies I took the back sear, although the YAK 52 is obviously soloed from the front. From both seats the visibility outside is excellent in every direction except forwards. Tailwheel pilots will automatically adjust to this problem; others should soon learn to compensate without too much trouble.
So what we have here is a complex military trainer with plenty of unusual controls, a 360hp engine that turns the ‘wrong’ way for western pilots, and limited forward visibility from both seats. It would be so easy to be intimidated, to climb back out of the cockpit and go and find a Cessna to fly instead. What a monumental mistake that would be.
Starting the engine is where the fun begins. To start and control a large, 9 cylinder radial with your own hands is a pleasure that is difficult to quantify. The actual starting procedure varies with the outside air temperature and the time since the engine was last run. A little chart on the right hand wall of the front cockpit tells you how long to prime the engine for. In Russia there is only one type of oil for piston engines and it is thinned out for winter use with varying amounts of petrol: the amount of oil dilution also enters the starting equation. Once again, do not be intimidated. The procedures are laid down and you simply follow them like running through any other aircraft checklist. When you get it right the belch of blue smoke and deeply satisfying rumble emanating from the front will reward you like no other pat on the back ever could. When warm the Ivchenko will start with the simplicity of your average Continental or Lycoming.
During taxiing the YAK seems a bit woolly at first but like everything else it is just a matter of practice. The rudder bars can be used for gently turns, helped when needed by a burst of power to energise the rudder. For tighter turns full rudder is used in the required direction combined with a squeeze on the stick-mounted brake lever to deploy differential braking. With the rudders in neutral, braking will be assigned equally to both main wheels. The power available up front means that a little care needs to be taken not to let the YAK get up to silly taxi speeds. Besides, the engine needs a while to stabilise its internal temperature so there should be no rush to the holding point in any case.
The engine run-up involves a simple mag check and an exercise of the RPM control to make sure that the propeller governor is working correctly. Pre-take off vital actions are more involved than normal and strict adherence to the checklist is the only way to proceed. Along with checklist discipline there are a few more items that will have been ingrained into the fledgling pilot before he/she gets to the runway. Going through the pilot notes before flying a new type should be a serious business, although some of the YAK 52’s book translation is amusingly suspect. For your edification: ceaseless engine function duration (max power duration) is 5 minutes; racing capacity (throttle-engine lag) is 3 seconds max; engine overspeeding when operating the throttle fastly (max overspeed) is 109 per cent; maximum allowed airspeed in level flight is conditioned by the avoidance of the sudden spin – 130kmh in normal flight and 170kmh inverted (I think that they might have got their max and min mixed up here). Also, when there are less than 4.5 gallons of fuel left, aerobatics are forbidden. Talk about flying to the edge of the envelope.
On the runway the YAK 52 comes into its own. With the throttle wide open the air blasting across the rudder gave excellent control authority. I only had about five seconds to remember to push on the wrong foot before 1335 kg of Russian hardware was ready to fly. A slight back pressure at 120kmh (65 knots) and ‘big bird’ was reaching skywards at nearly 2000 feet per minute. Take-off roll in ISA conditions is 590 feet at maximum weight. My first impressions at this stage were of the YAK’s awesome power and of its beautiful control response. The gear was cycled up with the airspeed below 200kmh (108 knots); once again I was time-warped from a veritable fighter cockpit to the front row of seats in a No.13 to East Acton. Despite being inexperienced with radial-engined military trainers I found that the Yak’s excellent manners quickly encouraged a feeling of confidence. The YAK 52 flies like a 360hp de Havilland Chipmunk. The aeroplane has a general feel that belies its size and weight. Control harmony is near-perfect, the control ratios for aileron, elevator and rudder approximate to 2, 3, 5, pretty close to the ideal 1, 2, 3. All control inputs give instant response. For primary training, stabilising springs can be attached to the stick to stiffen the YAK’s handling. In fact the aeroplane is so neutrally stable that this must be like putting outriggers on a pram. Without the springs, though not dynamically stable, the YAK makes a good instrument platform. Hands off, the aircraft’s inertia means that for some considerable time it will continue to go where one last pointed it. Full aileron deflection gives a roll rate of around 120 degrees per second. Pitch authority is awesome right down to the stall.
The YAK’s excellent climb rate meant that only 98 seconds after brake release we were levelling off at 3000 feet, a cruise setting of 75 per cent power causing the ASI needle to creep towards the metric equivalent of 140 knots, Mark Jefferies’ GPS suggested 145 knots after allowing for wind, although some of these systems are not as accurate as many pilots think. The whizz of a CRP 5 computer trued the indicated speed out to 142 knots, 164mph. The book figure gives 138 knots. A pessimistic performance manual (I never thought that I would see the day). Opening up to full power the ASI was past the advertised 158 kts point before we had to throttle back, lest we lose the Cessna 172 camera ship forever. Throttle response, or should I say racing capacity, is rather slow when compared to that of the usual Lycoming or Continental.
With a decent pair of headsets the noise level in the cockpit is low and the YAK’s intercom/radio system works perfectly – just don’t take your headset off. The noise without them is thunderous. The canopy can be opened in flight – a small knob on the left canopy frame controls a locking pin which locates holes in the rail beneath. It is important to make sure that the knob is in the hole. At one stage mine wasn’t and during the subsequent inverted flying my canopy opened fully, blowing my headset and glasses off in the process.
Between bouts of interaction with the camera ship there was time to explore the performance envelope. Despite the YAK 52’s weight and wing loading, stalls are predictable, the recovery simple. The clean stall with power off comes in at 57 kts. With gear and flaps this drops to 52 kts. A small dose of power drops the clean stall to 54 kts, the dirty stall to 49 kts. All stalls are heralded by at least 2.5 kts of buffet. The YAK has a tendency to drop a wing through a few degrees, although the wing that it chooses in any particular situation seems completely arbitrary. The wing can be held with rudder, not aileron, until stall recovery is established. Height loss in the stall is slightly greater than average for a light single-engined aeroplane, the worst of these manoeuvres losing around 200 fee. Spins can be initiated in both directions. The right hand spin is more stable and flatter owing to the direction of engine/propeller rotation. Loops and rolls are effortless, the aircraft equally happy to perform tight, violent manoeuvres at +7/-5G or large lazy figures at +2G. My personal preference is for large, low G, high speed manoeuvres using up a lot of sky. Mark Jefferies’ expertise lies in the advanced aerobatics world. In my vocabulary the pronunciation of the word YAK has three definitions – aircraft manufacturer, talk gibberish, and vomit profusely. With no desire to do the last two of these, I was allowed by Mark to do the sort of aerobatics that I preferred. The YAK’s airframe is so stiff that the general feeling it gives is one of great confidence regardless of the type of aerobatics one happens to be flying. Inverted flight in the ’52 is a non-event (providing you keep the canopy locked). The YAK’s airfoil section is not symmetrical although the aeroplane will happily fly inverted with only a small increase in power to counter the increased drag that his induces. To call the YAK 52 a 360hp Chipmunk does not do the aeroplane full justice; the YAK can fly advanced aerobatic/inverted manoeuvres considerably better than any Chippie. In 1984 a YAK 50, the single seat tailwheel cousin of the ’52 won the world aerobatics championship, with a very good pilot at the controls of course. The ’52 is not in the league of modern aerobatic superplanes a la Sukhoi 26, but it is not that far behind.
If you are not particularly interested in aerobatics do not preclude yourself from flying a YAK 52. There is so much more to this aeroplane than its aerobatic capabilities. The aircraft makes a good tourer. At 140 knots cruise speed we were burning just over 13 gallons of fuel per hour, giving an endurance in excess of 2 hours with 45 minutes reserve, a maximum range of 275 nautical miles with a slight reduction in cruise speed. The range could have been much greater but for the fact that the USSR wanted to discourage its pilots from using YAK 52’’ to defect. Baggage space is limited to what you can put on the shelf behind the rear seat. Mark Jefferies is currently addressing both these shortcomings with modifications to increase fuel and baggage capacity. Incidentally the aircraft is currently certified to perform its unlimited aerobatics at the max take-off weight of 1305 kg. An increase in baggage and fuel capacity will doubtless introduce a utility category of operation with lower G limits.
In the circuit the aeroplane is a delight to fly, the draggy fuselage combining with an excess of power to make large speed and height changes very easy to accomplish. The gear can be lowered at 200 kmh (108 kts) followed by the flaps at 170 kmh (92 kts). Without flaps the view ahead from the rear seat is virtually nil, ideally requiring a curved approach to the runway. With flaps extended it is only slightly better. The approach is flown at 170 kmh (92 kts) slowing to 120 km/h (65 kts) at the threshold. The YAK 52 is relatively easy to land and the high wing-loading means that there is no tendency to float. The aeroplane stays firmly on the ground once the nose is lowered. With practice the ’52 can be brought to a halt in 300 metres (985 feet). This is not exactly STOL performance but it does mean that the aeroplane can operate from 95 per cent of UK/Eire airfields.
In the past, the flying of warbird-like aircraft such as the YAK 52 was limited to a small number of rich and/or privileged pilots. With the collapse of the USSR and the associated devaluation of its currencies, incredible bargains are to be had both in the purchase and hire of its military aircraft. Although the market has stabilised somewhat, refurbished YAK 52’s can still be picked up for around US$30,000. Unfortunately there is a fair degree of risk associated with purchasing abroad. One recent story involves an individual handing over his money in an east European country, only to find the aircraft impounded by a local General who objected to one of ‘his’ aeroplanes being handed over to a westerner. At the time of writing the situation has not been resolved and the purchaser concerned continues to be separated from his money. The safe but still very cheap alternative is to buy direct from an importer like YAK UK. Prices start at around £30,000 ex-VAT for a factory-refurbished aeroplane, rising to £50,000 ex-VAT for a brand new example. This is exceptional value for money. At first glance the running costs for a complex aeroplane like a ’52 might seem to be prohibitive. In reality the inherent reliability of these aeroplanes coupled with the unbelievably low cost of spares means that a YAK could be cheaper to operate than a Pitts S2, Christen Eagle or a Chipmunk. A new Ivchenko M-14 radial retails at around US$12,000 bought through YAK UK and is good for 1000 hours of hard aerobatics. This is a lot cheaper than the powerplants in the western aeroplanes. Before you cry “2000 hours TBO on a Lycoming or Continental” observe that neither of these genera will survive for more than half their published TBO in an aerobatic environment. Propeller price for the YAK 52 is under US$3,000, not comparable to the US$10,000-plus cost of an equivalent western VP unit. UK-based Yaks are currently operated on the Russian and Lithuanian registers which further reduces operating costs, although forthcoming UK certification will allow Yaks to be operated under the British flag if desired. Aerobuild and Vintage Engine Technology share Little Gransden Airfield in Bedfordshire as a base with YAK UK. These companies can maintain and rebuild any part of a YAK 52. As a testament to their skills, Vintage Engine Technology have recently gained J
AR 145 approval for all aspects of radial engine construction and maintenance. Aerobuild are currently in the final stages of the complete refurbishment of a YAK 11, as wells as a ground-up restoration of a YAK 1 that has spent its last 40 years at the bottom of a Norwegian lake.
If you cannot reach to the outright purchase of a YAK 52, why not travel to Russia and hire one instead? The Skytrace Aerobatic School is based at Smolensk, midway between Moscow and the Polish border. In association with Arenair at Halfpenny Green West Midlands Skytrace offer varying packages of travel, aircraft training, hire, accommodation and food at unbeatable prices. Their instructors are Dosaff-trained, the school which looked after the induction of all civilian and military pilots in the days of the USSR. Prices for the YAK 52 start at US$69 per hour for pattern/instrument/formation/cross-country flying, rising to US$147 per hour for advanced/unlimited aerobatics. While you are there a fistful of dollars will buy some time in a single-seat YAK 55 or Antonov AN2 ‘flying bus’ biplane. A few dollars more will get you into a Russian M12 helicopter. Arenair hope to offer UK-based training/hire in the YAK 52 once CAA certification is achieved.
The YAK 52 offers warbird-like flying experience, for one quarter of the purchase price and one third of the operating cost of a Harvard. A YAK 52 is also a serious alternative to used western aeroplanes on the market, whether you are acrobatically inclined or otherwise. Inexperienced PPL and advanced aerobatic pilot alike, do not miss the opportunity of buying or hiring one of these aeroplanes with the rates as good as they are now: as Arthur Tyler of Arenair said, there is only one way that prices can go, and that is up…
Arenair/Skytrace Aerobatic School:
P.O. Box 31,
West Midlands, DY6 3YT
Tel. 01384 483118 Fax. 01384 483120
YAK UK/Aerobuild Limited:
Little Gransden Airfield,
Sandy, Beds. SG19 3BP
Tel. 01767 651156 Fax. 01767 651157
Vintage Engine Technology Limited:
Little Gransden Airfield,
Sandy, Beds. SG19 3BP
Tel. 01767 651794 Fax. 01767 651794