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Rotating Cylinder Valve SP eng., did any use it yet???

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Rotating Cylinder Valve SP eng., did any use it yet???

Old 01-17-2012, 02:47 PM
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larrysogla
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Default Rotating Cylinder Valve SP eng., did any use it yet???

I just came across the Rotating Cylinder Valve SP series engines here on RCUniverse on the airplane forum and I became curious because the post in the forum mentioned that it is a streamlined design and is very adaptable to being concealed inside the engine cowlings. So I went to the RCV manufacturer website and took a look at the RCV engine design operations and descriptions. It is a very interesting design especially the RSV-SP engine series. The engine piston and cylinder and crankshaft and propeller shaft are all pointing forward with the piston inside the cylinder and the cylinder inside the one piece propeller shaft/crankshaft. That is one very streamlined piston in a cylinder in a prop shaft/crankshaft combo design. INGENIOUS. Now the reason I asked if anybody has used it yet on a model airplane is because I noticed that the cooling fins around the "jacket" are NOT inline with the airflow on the airplane. My concern is...... "is overheating a concern with this RCV-SP engine series"??????? So has anybody used this RCV-SP engine series yet??????????? And if so.....how was it?????? Also looking at the factory specs....the power output of the .60 size RCV60-SP is .9 horsepower. That seems on the low end....even compared to other modern conventional design four strokes like the OS or Magnum etc. Your input is highly appreciated. Thanks.
Old 01-17-2012, 04:14 PM
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cutaway
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

I'd ask about its longevity. That has been an issue with many unconventional designs in the past like the OS Wankel and Aero .35. The power does seem on the low end. At the low RPM its turning, cooling probably isn't anything that can't be handled by some ordinary baffles
Old 01-17-2012, 04:43 PM
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larrysogla
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

Cutaway,
Thanks for your timely reply..........however, I made a mistake in describing the parts operation and description. The propeller shaft is not attached to the crankshaft but rather is attached to the cylinder. The cylinder is rotating at one half crankshaft speed because of the 2:1 reduction gear ratio. The crankshaft makes 2 turns for every 1 turn of the cylinder/propeller shaft assembly. The valve material that is rotating with the cylinder is continuously rubbing against the jacket walls. This is probably the part that will have the most wear. However, this is probably not as bad as the piston rings scrubbing continuously against the cylinder walls in a conventional design piston engine. I am sure, the designers have used the most wear resistant material available, as in this age of online search and e-mails, they can access good quality materials by e-mailing the source. Larry.
Old 01-17-2012, 04:57 PM
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

If you go into the Glow engine forum there is a factory support section for them. I built a plane some years ago for a customer and he required a hidden engine so I showed him the .91 RCV. He bought one and it fit in the 60 size hell cat just fine. To this day I haven't heard of this plane ever leaving the ground!
What I learned in my search of the RCV was they are to be broken in on a bench, not the plane, there is heavy vibration until they are broken in. From what I learned it took about two gallons of fuel to break them in! In my case the owner gave the engine to what he thought was a club engine guru to break in. The fellow put through a tank or two of fuel and dubbed it broken in!!
These are a gear driven engine and require the starter shaft or you can damage the engine using a normal starter.
They use a big, BIG prop and have gobs of torque.
In this case the plane was a Sky Shark scale kit and those were not only high dollar but really scale. This one came out looking like the real thing and turned into a hanger queen so I never got to see it run or flown but they are a true work of art.
Go check out the site, it makes for some fun reading. Not to mention a lot of knowledge for those of us that don't get to see this engine in use very often.
Old 01-17-2012, 08:35 PM
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

I have one in a Top Flite Spitfire. It too has turned into a hanger queen, but I hope to change that status in the spring. As for the engine, it does run hotter than a typical 4 stroke, but with adequate planning, that can be handled. In my case, being inside such a slim cowl as the Spitfire, and not wanting to cut big holes in the cowl, I came up with a novel solution. In addition to a close baffle, and in order to not have the traditional air inlet hole cut into the front of the cowl, I use the gap between the spinner and the front of the cowl as the inlet. In order to get the required airflow, I use a ducted fan to blow the hot air out, which creates a low pressure in the cowl to draw in cool air. This has worked out on all the ground tests, and the one aborted flight I had. The ducted fan was originally controlled by a proportional knob on my radio which controlled an ESC with it's own battery. I purchased and plan on using a thermocouple controller made by Oregon Scale Aviation, so the cooling will be automatically controlled by temp.

Gray Beard is correct about the break in proceedure, The engine vibrates like it's possesed when new. Two gallons is no exaggeration. After my first run, which was quite short, I found that every nut and bolt on the engine stand I made had come loose. Tripple check the prop nut before every run while breaking in. Also, it's easy to throw the starting bolt. Use the supplied starter adapter and don't try using a setup for helicopters, that's a sure way of throwing the starter bolt. After a while, the engine smooths out and runs nicely with a very unique sound. After the engine is broke in, it can be started with a high torque starter, like the DynaTron with 24 volts, off the spinner.

Because of the design of the engine, the body can be rotated to give a second setup for the carb and exhaust. This can be helpful for some subjects, but the standard setup was still best for my application. The glow plug is very uncomfortably close to the prop (which is huge), so I woud consider a remote glow a requirement. I would never try to start it with just a glow igniter. And since you are going to go with a remote glow, you might as well go with an on board glow system. On the Spitfire, I made my own with a NiMh C cell and a microswitch which is activated by a wheel collar attached to the throttle linkage. My glow comes on with the throttle all the way down and the trim at about 1/2. As the plane throttles up, the collar clears the switch and shuts the glow off at about 1/3 throttle.

If you fly at a field with any traffic, be prepared for a crowd to gather around.

Hope this answers some of your questions.

Video link for a ground run
http://youtu.be/ZpwJ0XYTeIU


Scott
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Old 01-17-2012, 09:59 PM
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larrysogla
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

Saramos,
Thanks for the video of the ground run. That was some cool sound. Very unique. Hope you have many good flights with the Spitfire/RCV engine combo.
That is definitely a very uinnique engine design, like no other......piston, cylinder, propeller shaft all three pointing in the same direction.....towards the front of the airplane.
Larry
Old 01-17-2012, 11:14 PM
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saramos
 
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

What part of LA are you in? I am a San Fernando Valley RC Flyers member out of the Sepulveda Basin.

Scott
Old 01-18-2012, 12:55 AM
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larrysogla
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

Scott,
I live in West L.A. I come to the Sepulveda Basin Apollo Field once in a while just to watch. I haven't flown in about 2 years. Just too many things on the plate. My boss at work is a San Fernando Valley Flyers member. His name is John. I believe he is about to maiden or already maidened a Troy Built Model AT-6 with a 90 Four Stroke O.S. Say hello to him for me if you see him.
Larry
Old 01-18-2012, 01:06 AM
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

The RCV SP is reasonably common in the UK. I haven't used one, myself, 'cos I'm a bit leery of "new stuff". (Actually, it's been around for more than a decade, now, so it's not really "new")


I hear that cooling is a bit of an issue ... but that's probably because we modellers don't often give cooling a second thought. A bit of sensible ducting will ensure a proper cooling airflow over the fins.


Here's one in a JU 87 http://www.youtube.com/watch?v=W1ONYgv_Jxo


This is the YT JU 87, which is identical to the KMP JU 87. So, a substantial model.

I would imagine that the engine is reliable, owing to the large rotating mass (big prop) and the gearing. This should make it reluctant to quit, so long as there is fuel. Well, that's been my experience of geared drives. Lots of prop drag, too, at idle... lovely.
Old 01-18-2012, 06:11 AM
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Default RE: Rotating Cylinder Valve SP eng., did any use it yet???

Here is a neat cutaway video of that engine [youtube]http://www.youtube.com/watch?v=rCChLocCp_g[/youtube]

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