RCV engines

[Solly]

Why don't we see more RCV engines in general use? I have six examples, three of the CD type, and three of the SP type. They are all excellent, easy to start and just don't quit in the air. Fellow club members come up to me and express surprise that I have such success with them - they apparently have heard negative reports from another source. It's true that early examples from about eight years ago had problems, and also true that the SP series needs specific cooling ducts, but I find the present range really is very good. My recent purchase is the 130CD which I use to power a Seagull giant PT-19. Let me hasten to add that I also operate Laser and Saito engines both of which are superb. It's just that the RCV engines don't seem to be as popular, and from my experience they should be.

[Stephen Jones]

Hi Solly,

I Have a RCV 60Sp not sure just how old it is , i will see if i can find my receipt .

But i can tell you that i bought it due to having problems with my other 4 Strokes cutting mid flight , i admit they are well use but i would not of said they where too old or over used .

So i decided to give the RCV 60 sp ago and have had no end of trouble i even made a special cowl to deflect air in and around the engine then out through the back .

I found mine too noise , too much vibration and so had to keep beefing up the firewall .

It too would cut out mid flight , and the tiny muffler came off it. in the end i give up on it as a replacement would of cost to much from Weston uk at over £70 .

It remains stuck to the front of a Acro Wot to this day .

Steve ( Not too Happy with em )

[Jon H]

My only direct experience was of a 120 sp and it was perfect...on one propeller. any other prop it didn't want to know at all and behaved very much as Stephen said.

Also the behind prop starting is bloody lethal. trying to lean over the model and start it is not a clever idea. I just started it the normal way and all was well.

Its a shame as the design is quite clever to say the least

[Solly]

Hi Steve. Yes, I have a fellow club member who had a very similar experience. His engine was one of the first produced and sounded like a bag of hammers. I have one of the re-engineered engines and it's a completely different experience. It runs much quieter (and cooler) and feels silky smooth when turned over by hand. I use 10% Prosynth 2000 fuel, although I find 10% Duraglow is good too.

[Stephen Jones]

Hi Solly,

Yes a bag of hammers describes it very well , i also use 10% Duraglow .

A waste of £200

Steve

[Jon H]

Stephen, the exhaust on it is (I think) the same thread etc as an OS, which means an exhaust for an ASP off hobbyking will do the job. It wont address the bag of hammers issue however.

Regarding your fuel choice, if memory serves RCV don't like castor in the fuel and duraglow is really heavy on the castor. It might be a contributory factor?

[Bob Cotsford]

I've got a 90CD in a Hangar 9 SNJ (Harvard). It was second hand so I don't know how old it is but I'm pretty sure it's old. From cold it sounds like a tin box of bolts being shaken but once it warms up it's fine. It is certainly a reliable runner but I don't think it can match other brands in terms of power output. Not my ASP 91s at any rate.

Then there is the offset engine mounts, something else to take account of when mounting it in ARTFs. Add in OS/Saito class pricing and limited distribution and you can see why they are not more popular.

Of course they do have one big advantage in that they are a very low profile for a four stroke. They also seem pretty insensitive to needle settings and fuel types. I've changed from Southern Modelcraft 5% to Model Technics Dynaglo to Laser 5% and not touched the needle.

[Cuban8]

Very clever designs, but could never understand the logic of producing a product that given the conservative nature of many aeromodellers, would always be an expensive niche item? Early production problems certainly didn't help either - get a bad reputation at the start and it's difficult to shake it off. In the two clubs I'm a member of, I've only ever seen one RCV engine used and was mightily unimpressed by it's performance. A great shame as I'd really like to support a British firm, but with a reliable ASP 91 or 120 as opposition (Lasers and OS are a bit out of my pay scale) the choice is obvious.

Edited By Cuban8 on 17/10/2014 12:03:55

[Jon H]

I could be wrong here so feel free to correct me if you know better....but I believe the engines are made in china even though the design is british. My understanding was that the prototypes were made here and everything was fine and dandy, So it was shipped off for production but as the Chinese are less hot on their QC quality suffered but was more noticeable on this particular engine due to the tight tolerances required for the sleeve valve to work correctly.

The other thing could be that an unconventional engine needs a different operating method than what modellers are used to so this again could be causing problems. This was certainly true back in WWII when sqn's swapped the well known merlin for the new Napier Sabre. Sure the Sabre had its problems, but apparently about half of the reported failures came down to mishandling leading to overheating or some other issue that eventually broke the engine.

I have been meaning to pick up an RCV to play with, but didn't want to pay full whack just to indulge my curiosity

[Cuban8]

If they're made in China now, then I really wouldn't bother with one.

[Former Member]

[This posting has been removed]

[Jon H]

Posted by Cuban8 on 17/10/2014 12:54:16:

If they're made in China now, then I really wouldn't bother with one.

I think they always have been, only the prototypes were made in the UK as far as I am aware. If anyone has a box for the engine it will doubtless reveal all about where it was made. But, if they have sorted out the QC issues then the engines should work well irrespective of where it is made. That said, the price is steep for a Chinese engine, if it was made here then the price is good.

[Martin Harris - Moderator]

I've read that OS are building their 2 strokes in China these days.

I acquired an RCV 91 CD in a very vintage Sterling Stearman which it powers very adequately. It's a model which I flew many times for the owner and when he was downsizing his fleet due to moving into sheltered housing he more or less insisted on selling it to me for a stupidly low price - I managed to pay a bit more than the asking price in the end...

Part of the deal (on pain of unending nagging) was that I would use the specified Model Technics Duraglo (9% E.D.L. (synthetic oil) and 6% castor) fuel recommended (and coincidentally supplied) by the original importer supplier and he supplied me with several gallons as part of the deal. He was absolutely convinced that this fuel was the key to a long life and it has certainly always run reliably. The new supplier has changed their recommendation to a different fuel which by a happy co-incidence he just happens to supply...

Last spring, the engine started making some decidedly odd "catching" noises in the air and I changed the bearings - the engine was in good condition inside when stripped and it seemed that the cylinder bearing was the cause of the noise although my investigation wasn't particularly conclusive - it seemed to catch when first stripped but then felt smooth after a short time while I was looking into the cause - an undetected foreign object perhaps?

After reassembling with new bearings it runs perfectly again. I've always found it to start easily and perform well on the 14 x 7 Graupner Super prop that it came with.

Checking the engine's box shows no indication of the engine's origin - and in any written matter that I've come across I have never seen any reference to its origin other than that it was British designed. I think that most suppliers would make a point of trumpeting British manufacture so I have drawn my own conclusion...

Edited By Martin Harris on 17/10/2014 21:09:17

[Stephen Jones]

This is my 60 sp.

I believe that the CD range have always been the better of the two and only introduced due to modelers having problems finding a prop to fit the engine/plane.

I would gladly swap this for a RCV 58 CD ,

I wonder just how many offers i will get , hay i will even throw in the props i bought for it.

Steve

[Jon H]

Stephen, bin the wooden prop. my experience shows that these motors need a big heavy prop to get the flywheel effect. You also seem a little skinny on pitch as that 8'' pitch is only half due to the low prop rpm. Weston suggest a 15x12 2 blader or 13.4x13.5 (god knows if this even exists) 3 blade.

Martin, not sure about OS making engines in china but I did hear a suggestion that the Sanye manufactured engines (asp sc magnum) are basically made under licence, which might explain why they look like the old FX range. Lets be fair, its good business to sell your obsolete engine design to someone and make a small profit from each one than to only make a profit from your current range. OS knew people wanted cheap, and that ASP would take some of their market, so.... as the adage says, keeps your friends close...

Edited By Jon Harper on 17/10/2014 21:58:28

[J D 8]

.

Also the behind prop starting is bloody lethal. trying to lean over the model and start it is not a clever idea. I just started it the normal way and all was well.

You do not start an RCV SP by leaning over the prop, you do it from behind the motor. Have one in my seagull SNJ just love the sound very radial like.

[Jon H]

I didn't lean over the prop, I had to lean over the whole model which was way worse!

[Tony Richardson]

Quick question, anybody on here running a RCV58 CD, I have one and have had it for quite a few years, we moved a couple of years ago and this engine has not been run since then.

I removed it from my Sig Rascal and planned to install it in another model - a low wing sport model - my dilemma is it runs but not very well and yes I did use after run oil and store it correctly, it does not want to idle except at a very high RPM and transition is sluggish.I did partly disassemble and flush/clean  the carb and started back with the factory default starting settings and thought I was back to my original settings but something is certainly off somewhere, also compression does not seem as high as I remember it, could I have a stuck or broken ring? thoughts anyone..

Edited By Tony Richardson on 16/05/2020 22:26:34

Edited By Tony Richardson on 16/05/2020 22:28:08

[J D 8]

Could be O ring on needle valve gone hard. As you say may be stuck ring, run it some more.

Old post. revival here.

[Tony Richardson]

JD8 I was thinking hard O ring as well, I have two sets of instruction/owners manual with this engine and in one it says the starting setting for the low speed should be set with the throttle fully closed then back out 4 turns the other manual says just the opposite, ie open throttle fully back the low needle all the way out then screw in 3 1/2 to 4 turns, anyone have any idea which one is correct as I found the low speed setting to be really sensitive when it was in the Rascal, totally confused now LOL.

[Richard Clark 2]

I've got two of the 58CDs, both purchased at the same time, some years ago, from the local model shop. One was for a Graunper 63 inch Bolkow ARTF, purchased as being no taller than a two-stroke it would not protrude from the cowl as a conventional four stroke would. I was also building a Flair SE5 at the same time so as I was in the shop I bought one for that too.

They both seemed ok at first but after a while one lost compression and thus power, and the other would never hold the idle needle setting, as it gradually richened up as the throttle turned. I fixed that by adjusting the idle needle carefully and putting a blob of silicone sealant on top of the needle in its threaded hole and have never needed to adjust it since.

As for the poor compression of the other one I got a new piston ring from Weston (see below) and it's been ok since. Though neither plane gets much use. They are a bit rattly at tickover but you don't notice in the air.

I suspect the vibration of which some people complain is no worse than any other engine and only noticeable on the SP as it is 'backwads and forwards' and the former to which it is attached acts like a diaphragm.

THE STORY

They were designed and made by a small, fairly long-established, engineering company near me. Simply because one of the owners appeared to a model plane enthusiast (I used to see various planes, with both RCV and other assorted engines in his car). They sold quite well initially and the CD versions sold even better.

As they were nearby I went to them for the piston ring but was told rather curtly that they had sold the whole thing to Weston including all the spare parts. I think Weston, not the original RCV company. arranged for them to be made in China.

I think the company had 'delusions of grandeur' and weren't interested in 'toys' any more. They made prototype bigger ones supposedly suitable for small motorbikes and tried to get Honda and Vespa interested. With no success. The problem was high oil consumption. Ok in model planes where we mix oil with the fuel but useless in motorbikes, even small ones, nobody wants to keep putting oil in and they won't pass the vehicle pollution regulations. All rotary valve engines have suffered with this. The earlier Cross and Aspin engines failed for that reason.

As for 'today' I see Weston only list the 58CD. All the others seem to have vanished.

[Martin Harris - Moderator]

Interesting. I was always under the impression that they were made in China long before Weston took over. It seemed odd that there was never any mention of where they were made on the packaging or published literature although there were references to being designed in the UK. Were these perhaps prototypes or being assembled from batches of components produced elsewhere? Did you see the parts actually being made?

[Paul Marsh]

I have a SP60 and 58 CD. Both are pretty gutless and horrible. Had the 58 in a YT Taylorcraft, and used to fly it in YT trade slots, but needed full power all the time to fly. Eventually I had to lean the needle right out on a hot day at the club and blew the con rod. No damage, and got a new one off Weston ok, and put in box. Swapped it for a OS52FS and way more power.

[Solly]

I have a selection of RCV engines, I had a couple of the 90SP types which I used but came to the conclusion they weren't really a practical power unit for the hobby. However the CD types have proved to be good reliable engines. I particularly like the 130CD which I am currently using in a Seagull giant scale PT19, plenty thrust and has never quit in the air. I suspect the 58CD will be the only one available in the future, although I hear that production is moving from China to India.

[Richard Clark 2]

Posted by Martin Harris on 17/05/2020 14:58:54:

Interesting. I was always under the impression that they were made in China long before Weston took over. It seemed odd that there was never any mention of where they were made on the packaging or published literature although there were references to being designed in the UK. Were these perhaps prototypes or being assembled from batches of components produced elsewhere? Did you see the parts actually being made?

I never went into the factory itself, and I very much doubt it had a pressure diecasting facility, so the crankcases of the CD58 would have been 'farrned out'. The two engines I have appear much better made than the typical Chinese ones of the period.

Paul,

I never found the 58CD "gutless" and the couple of magazine tests I read found the CD58 as powerful as anything else. Not 'horrible" either. But I thought the SP ones had more disadvantages than advantages which is why I was never tempted to buy one.