Russian Radials - Aeroplane Magazine 2014

s v o s t e v Sh in Shakespeare country Richard Paver reports from a strip near Stratford upon Avon, where former Soviet-Bloc trainers are getting a new lease of life

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n March 2014 I visited Russian Radials Ltd at Atherstone near Stratford on Avon to meet and interview the founder of this specialist Shvetsov and Vedeneyev aero-engine rebuild business, Andrew Holman-West. The Shvetsov ASh-82 engine and the Vedeneyev M14 engine are the types fitted specifically to the Yak-11 and Yak-50/52 respectively and Russian Radials Ltd provide a full overhaul, specialist maintenance and rebuild service for both of these types of engine, as well as the larger twin row ASh-82.

Andrew is an experienced pilot and owns a Yak-50 (G-YKSO) and a lovely Yak-11 (G-BZMY “White 1”) which he keeps and regularly flies

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from a private strip at Atherstone close to the workshop. Atherstone (which was also known as RAF Stratford) is a former RAF airfield approximately three miles south of Stratford upon Avon opened in 1941 to act as a satellite airfield for RAF Wellesbourne Mountford and was used by the 22nd Operational Training Unit flying Wellingtons during the Second World War. The airfield closed in October 1945, however much of the original layout can still be made out and a small number of industrial and warehouse businesses are now located on the site around the periphery and connected by the original peri track. Andrew has a small hangar on the site and maintains a grass strip parallel to one of the former runways.

I met Andrew at his office in nearby

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ABOVE: Andrew Holman West, the owner of Russian Radials, flying Yak-11 G-BZMY “White 1” from his home strip at Atherstone near Stratford on Avon, on June 10. RichARd PAvER

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Visit RussianRadials.com for further information Atherstone and asked him about the origins of Russian Radials and his future plans for the business. He said: “I’ve been flying my own Yak-11 and Yak-50 for some time now and a few years ago it became apparent to me that in the future there would be an increasing demand from Yak-11 and Yak-50/52 owners all over Europe for a specialist engine maintenance and rebuild service provider in t

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view of the large number of these types that are currently been flown in Europe. In previous years it was easy for Yak-50/52 owners to partexchange damaged engines for either brand new or newly overhauled M14 engines but as they are no longer manufactured they are now becoming increasingly difficult to obtain and expensive. With respect to the ASh-21 engine in the Yak 11 there has never been a specialist maintenance outfit for these engines in Western Europe and owners have been relying heavily on either acquiring and holding complete spare engines (often of dubious provenance) or of cannibalising other engines in order to keep the type operational. The issue came to a head a few years ago when I needed to overhaul my own ASh-21 in my Yak-11 as I had lost confidence in the engine – having experienced the compressor shearing off and then subsequently finding metal in the filters.

At that time I was approached by Rob Davies to discuss rebuilding his ASh-21 for his Yak-11 (G-YCII) which had suffered a shock load in an accident at North Weald.

In addition I wanted a further spare for my aircraft which I wanted to have restored to zero hours to keep in reserve.

“I therefore had at least three ASh-21s requiring overhaul and, because safety was my primary concern, I decided to establish a new specialist aero engine maintenance organisation of my own where I could be sure of the quality of work turned out (I had yet to find anyone in the West who had a set of manuals). I managed to source the various technical manuals and have them translated and recruited John Bailey to be our chief engineer. We have workshops on the Atherstone Industrial estate adjoining the strip from where I fly and since establishing the business we have now added CAA A8-20(M5) approvals which permit us to carry out and certify both engine and airframe work. The first customer engine that we completed was the ASh-21 for Rob Davies Yak-11 (G-YCII) which is now being regularly flown and the second was the ASh-21 in my own Yak-11 (G-BZMY).

To demonstrate the confidence I had in our work, last year I flew G-BZMY behind this engine some 3,500 miles to the Ukraine and back to attend an airshow at Belbeck in the Crimea, without any problems, which I believe is testament to the quality and reliability of the engine we have achieved. We now have two further ASh-21 engines under rebuild –

one is from Mark Rijkse’s Yak-11 (G-BTZE) which is currently with us for a shock loading inspection, plus we have the spare ASh-21 for my own Yak which we are working on so that I can have a spare zero time engine available for my own aircraft. We only reckon to be able to rebuild about two engines per year - it is approximately a six-month process and a complete strip down, clean, NDT, repair as necessary, rebuild and test rig runs will cost approximately 60,000 dollars depending on what additional new components may be required once the engine has been inspected. Our business philosophy is very much not to compromise on quality and we are very pleased to have become a niche low volume operator in the specialist aero

ABOVE: Andrew Holman-West goes through the cockpit drill before a flight in his Yak-50, G-YKSO. RichARd PAvER

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engine business.”

I asked Andrew about the challenges for owners of keeping these types of rare vintage engines operational: “These big radials are very unstressed when they are set up correctly and will generally continue to operate even if they have been abused in the past. The two biggest risks for keeping them serviceable is not component material failure on any of the key wearing parts but it is the risk of engine failure due to corrosion or hydraulic lock which can break a con rod. Internal corrosion can quickly occur

ABOVE: A cylinder from Mark Rijkse’s Yak-11. RichARd PAvER

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ABOVE: Yak-11 G-BZMY “White 1”, seen at 6,000ft in the vicinity of Stratford upon Avon during a photo shoot on June 10. The Piper Aztec camera ship was flown by Lydd based-pilot Bill Giles. RichARd PAvER

if an engine is out of use for extended periods without being regularly maintained or properly inhibited. Moisture will build up in the engine internals and corrosion will set in which can cause engine failure if not quickly addressed and so the worst thing to do with these engines is to leave them inactive with little or no attention being paid to them, even if they are stored under cover. Hydraulic locks also easily occur which can very badly damage the engine – when the engine is not run or turned over regularly oil can drain past the bottom pistons and collect in their combustion chambers. On start-up, since this oil can’t be burnt or ejected through the valves and, as it won’t compress either, if it isn’t drained before the engine is started it will lock the piston of the affected cylinder and potentially severely damage or in some cases completely break a con rod. On discovering a hydraulic lock (by turning over the engine by hand prior to any start) the proper procedure is to take a plug out and drain the collected oil before any start attempt is made.

“Hydraulic lock damage can take time to manifest itself but the result is usually catastrophic to the engine when a con rod shears. That said, these

are beautifully built engines designed to be operated under very low stresses and so if properly maintained they should have a very long life. A properly maintained ASh-21 is good for at least 850 hours and an M14 which was designed to have an even longer life will do a couple of thousand hours. For the average owner who might fly 50-60 hours per year in a type such as a Yak-11 a new engine will last for a considerable part of their entire flying career!”

Andrew then took me to the workshops of Russian Radials Ltd and introduced me to Chief Engineer John Bailey with whom I discussed the work of the company in further detail. At the time of my visit the ASh-21 from Mark Rijkse’s lovely Yak-11 was in the workshop having been completely dismantled by John for a shock load inspection. This engine was in the stand and was in the process of being re-assembled during my visit and in addition there was Andrew’s ASh-21 spare being overhauled plus an M14 engine which was close to completion for a Yak-50 owner.

John showed me the fuel injection pump for Andrew Holman’s spare engine which had recently been overhauled by Mike Nixon’s Vintage V12s in the USA and was now ready for re-fitting to the engine. John explained: “The fuel injection pump for the Ash 21 is an absolutely beautiful piece of engineering and

“These big radials are very unstressed when they are set up correctly and will generally continue to operate even if they have been abused in the past.”

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is extremely similar to the fuel pump that was designed by BMW during the a Second World War and fitted to the Fw190. Reputedly Shvetsov copied the BMW design during the war and used this on the ASh 82 engines that were fitted to all of the Soviet Union’s radial powered aircraft from 1942 onwards, including the Lavochkin La-7 and Tupolev Tu-2. It is a truly ingenious system so to learn that it has a BMW design heritage comes as no surprise.

The internal fuel injection system is based on seven plungers injecting the fuel, controlled by a hydraulic regulator which varies the injection rate and also a pressure cell which can sense both altitude and throttle setting to vary the amount of fuel passing into the cylinders.”

I then asked John Bailey about how they went about acquiring all the necessary manuals and written information on how to overhaul these engines when setting up their business.

John told me: “We’ve been acquiring the manuals for many years now and they have taken considerable time, a lot of money and a lot of searching to assemble. They do exist but they are likely to be tucked away in libraries and military records archive stores and as such are very difficult to locate. The ASh-21 engine for the Yak-11 requires five manuals: the technical description manual, the field service manual, the overhaul manual, the parts manual and finally the installation manual. Bearing in mind that each of these individually is likely to be at least 200 pages long and written and illustrated in either Russian or another Soviet bloc language then you will get a good idea of the challenge and enormous work involved in assembling the basic paper work in English before an overhaul can be contemplated. At the very minimum you must have the overhaul manual and parts manuals available and translated and preferably the others too. The field service manual in particular is very useful as it specifies what maintenance can be done to the engine in the field without the need to t

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ABOVE: Fuel injection pump from an ASh-21.

RichARd PAvER

ABOVE: The engine-bay at the Russian Radials Workshop, with an M14 and ASh-21 awaiting attention. RichARd PAvER

take the engine out and into the workshop.”

I then discussed with John how easily internal components and parts can either be newly manufactured or obtained from other

“The ASh-21 engine for the Yak-11 requires five manuals: The Technical description manual, the field service manual, the overhaul manual, the parts manual and the installation manual.”

ABOVE: Rob Davies in his Yak-11, G-YCII, with Mark Rijske formatting in his Yak-11, G-BTZE. RichARd PAvER

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sources to keep these engines operational today. It became clear that due to the complexity of the engine itself it is impossible to give a generalised answer to this question and basically some parts such as con rods and cylinders cannot be remanufactured and have to be obtained by cannibalising another similar engine, some parts such as rockers arms, bearing bushes and cylinder liners can be repaired while other parts such as shock absorbers and engine bearer and engine mounting bolts can be newly manufactured to the original manufacturer’s specification. A detailed analytical process has to be followed before a newly manufactured part can be commissioned. For example on the Yak-11 there are four engine bearer bolts which attach the bearer to the fuselage and then a further seven bolts that attach the engine to the bearer itself. These require replacement after a certain number of hours due to vibration and constant use but if new originals cannot be sourced then they have to be remanufactured. Before this can happen an original bolt has to be submitted for a detailed assessment of both its tensile strength and also the specification of the original material. To test tensile strength a

sample of the bolt’s material is cut off and then shaped into a dog bone shape and attached to a test rig to stretch it until it breaks. The point when it breaks under stretch determines the bolt’s tensile strength and in addition further material is shaved off the bolt for analysis as to the material make up eg the proportions of high grade steel, chrome or manganese that are contained in the material. When the material specification and tensile strength have both been determined this data is then presented to the CAA’s structural engineer for agreement on what specification the new bolts will be manufactured to. When this has been agreed the challenge is then to find a specialist bolt manufacturer who is willing to make a limited batch of bolts, ie a small number at a reasonable cost. This whole process is both time-consuming and expensive and has to be completed for any parts that are going to be remanufactured, so it is easy to understand how overhaul costs for such specialist vintage engines are so expensive.

The ASh-21 engine has seven cylinders and with 14 valves in total - seven inlet and seven exhaust. The inlet valves are made of solid

material as they are cooled when in operation by the incoming cold air into the cylinder but the exhaust valves are completely different and are sodium filled to aid cooling. When the engine is running the sodium in the valve heats up and then splashes end to end as the valve moves up and down in its guides and as a consequence of this movement of sodium, heat is transferred from the valve into the oil.

In restoring these valves, metal material had to be shaved off a sample valve stem for analysis but no one knew how deep the metal material was and whether the shaving process might puncture through to the sodium, as the metal shaving process uses water for cooling and as water is explosive when mixed with sodium great care had to be taken. The analysis showed that the ASh-21 valves were made up mainly of iron with nickel and chromium and other trace elements. This was deemed compatible with modern hard chroming plating methods so these valves could be refurbished to an agreed spec and approved by the CAA in this way. During a full overhaul it is also standard procedure for John Bailey to clean off the hardened carbon deposits which build up on t

ABOVE: A newly-overhauled propeller hub for a Yak-11.

RichARd PAvER

RIGHT: Chief Engineer at Russian Radials, John Bailey. RichARd PAvER

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ABOVE: Russian instructional charts on the workshop wall. RichARd PAvER

all the engine internal components during the lifetime of an engine. Over time the heat bakes the carbon on to the internal components and when these deposits accumulate this can then detrimentally affect the internal cooling efficiency of the engine so all components are subjected to a deep clean in an alkaline solution when the engine is dismantled.

The ASh-21, in common with all Russian aero engines, was designed to be as repairable as possible. Some wear items, like piston rings for example, were relatively inexpensive and would be better replaced, and other components were deemed too highly stressed to consider repairing so they would be replaced also but other high-value components were too valuable to discard if they just showed signs of wear.

Provided the component passed NDT and microscopic inspection the overhaul manual details all the various processes that could be safely performed on that component in minute

ABOVE: Newly overhauled exhaust valves for a Yak-11. RichARd PAvER ABOVE: Rocker bearings after cleaning.

concerning the Crimea it is perhaps remarkable to report that in 2013 Andrew was invited to detail. The cylinder heads all have replaceable fly his Yak-11 to an international airshow at threaded inserts to avoid scrapping an the Ukraine airbase of Belbeck which has since otherwise serviceable cylinder in cases of thread been taken over by Russian forces. Andrew wear. All bearing surfaces are replaceable and flew from the UK to the Crimea accompanied there is a list of all engine components whose

by Rob Lamplough in his P-51D Miss Helen worn surfaces can be restored by hard chrome in July 2013 and flew for over 25 hours in the plating or other plating process.

Yak including the transit flights and airshow When Rob Davies recently overhauled his appearance. He said that during this Yak-11 he commissioned Avia Propellers in mammoth transcontinental flight the Yak Prague to manufacture a batch of brand new engine performed perfectly and the only prop blades for Yak-11s as these had been serviceability issue that he suffered was a impossible to find. He has recently fitted his Yak- binding brake on one of the main wheels 11 prop with a set of these brand new blades which he managed to get fixed before arrival at and the new prop had just been delivered for Belbeck. Andrew said that the flight planning fitting to the aircraft at the time of my visit. Avia logistics and obtaining all the necessary still had the full design details plus the ability approvals to transit across many international to manufacture new blades which has proved to boundaries was the biggest challenge for this be invaluable in keeping these types in the air. trip and a number of other Continental In view of the current international crisis warbird operators were invited too.

RichARd PAvER

BELOW: The compact but purposeful Yak-11 must be counted among the most svelte of all radial-engined aircraft. RichARd PAvER

“When Rob Davies recently overhauled his Yak-11 he commissioned Avia Propellers in Prague to manufacture a batch of brand new prop blades for Yak-11s as these had been impossible to find.�

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