Hi guys, one of my fellow club members is considering purchasing a RCV 91CD engine because he wishes a 4 cycle but would prefer not to have to deal with valves and adjustments. He is asking about the long term reliability of this model.

Please give your comments, either bad or good.

Please note this is the CD version.

Sackie

Here's the company web page. http://www.rcvengines.com/rcv91cd.htm

These engines never seem to have caught on. I'm not sure why.

I would suggest that he purchase a Saito or an OS four stroke. I prefer Saitos, but my OS .91 Surpass is over 20 years old, and still in service.

In my opinion, valves are like our needle valves. They don't require frequent adjustment. Depending on how much he uses the engine, it shouldn't require valve adjustment more than once a year.

Originally Posted by TomCrump

Here's the company web page. http://www.rcvengines.com/rcv91cd.htm

These engines never seem to have caught on. I'm not sure why.

I would suggest that he purchase a Saito or an OS four stroke. I prefer Saitos, but my OS .91 Surpass is over 20 years old, and still in service.

In my opinion, valves are like our needle valves. They don't require frequent adjustment. Depending on how much he uses the engine, it shouldn't require valve adjustment more than once a year.

I do remember meeting the fellow that did start up the company at the annual engine swap meet at Watford, did buy on of his very early engines, not sure if you could call these prototypes. Friend collector Danny Claes was there with me, I seem to remember he also did buy one of the very early engines. He may recall the name of this guy. We were asked to promote these engines. I remember that we told him that the market was not really waiting anciously for the design. I think I do have one of the older design engines and two of the totally different follow-up designs. These first models were designed to be started into a provision atop the engine with an hexagonal bit fitted in an electric drill. Not sure if I have pics on this laptop but I will check when back home on monday. But I am sure Danny will know all about it.

I have a RCV 60 SP and a 58CD. I have run the CD with no problems, the SP is for a future project.
The designers name is Keith Lawes. The RCV company is based in Dorset, England but the engines are manufactured in China by Sanye (manufacturers of SC, ASP and Magnum).
They have a good reputation for customer service, there is an extensive thread on RC Universe which includes many replies from the RCV Service department. They are now sold and serviced by Weston UK.
The SP series engines need a careful cooling arrangement but the CD series does not seem to have any apparent problems.
Graham

I have two of the .58 CD RCV engines, that I plan on putting in a twin engine plane one of these days. I just haven't gotten around to it yet. But the engines ran fine for me, no problems were encountered when I was running them.

I don't see any problems with long term reliability using the engines. They are going to have the same issues any other engine design will have with things like crankshaft bearings or piston rings and so on. They do have support for getting parts and repairs done if you don't want to repair it yourself.

I can see some benefits with the design that should yield good long life out of the engines. The conventional poppet valve model engines all have problems lubricating the camshaft area, lifters and rocker arm valve assembies on them. Some of the poppet valve engines do lubricate these areas quite poorly too. But the rotary sleeve valve engine doesn't have that same lubrication problem with it's design though. The sleeve valve design also has fewer moving parts in that relation too.

Years ago I flew a Webra T4-80 rotary valve engine for a long time and it didn't have any problems at all. It was very reliable. It just ran and ran. So I don't see any issues with the RCV engines either.

Here is some paperwork I was sent at the time. Drawing is of the first model they made.

I own an RCV 91CD, and a few RCV 58 CDs, and never had a problem. They're reliable, compact for their displacement, you don't see them too often, and their performance improves markedly after a careful break-in. The only irritation I've experienced is a tendency for the exhaust pipe and muffler connections to leak. That's not a big deal and I wouldn't hesitate in buying another RCV product or recommending them to you. RTC

One thing I've noticed about the RCV engines is a lot of guys buy them, and try to turn them as fast as similar poppet valve engines. With the smaller, low pitch props, they appear not to perform too well. One has to remember that the RCV drive hub is actually the cylinder and it is driven by gears at half the crankshaft speed. The correct sized prop can make all of the difference in the world.

Saltmine, RCV makes two types of engines, a SP and a CD version. One uses direct drive and the other is a inline gear reduced drive version. The direct drive CD version has the prop directly off the crankshaft whereas the SP inline version has the prop driven off the top of the rotating cylinder sleeve. Both types of engines come in three different displacement sizes.

But yes with the inline SP version you use larger props. The SP type of engine was intended more for scale applications where folks want to use a scale size prop on their plane. The CD version of the engines is used like a conventional four stroke engine is used. But the CD version has a much lower profile to it, or height and is quite suitable for putting inside of a cowl in a airplane too.