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Showing results for 'RCV engines'.
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Forum members' new models: Let's see them.
PeterF replied to Paul Marsh's topic in All Things Model Flying
Are newish or half new models allowed in the thread. I have an 81" Brian Taylor Mosquito that flew with RCV 60SP engines for a number of years. I had an engine out incident a couple of years back and could not get back to the runway and the model landed in a hollow in the rough pasture outside our field. The fuselage did not actually hit the ground as the wings landed on the lips of the hollow. The fuselage was hardly damaged because it did not tough the ground, but the wings were badly broken. I have now built a new wing rather than trying to make major structural repairs. As I have converted entirely to electric flight in the meantime, I have rebuilt it as electric power. Interestingly, the electric version weighs 17lb 12oz ready to fly, the IC version weighed exactly the same dry (without fuel). Hyperion ZS 4025-16 320kV motors with 16x12 APC E props driven by 6S 4000mAh batteries through HobbyWing Platinum 80A V4 ESCs. Measurements gave 6,450rpm at 22.3V with 47.5A, so about 1050W each = 2100W. The pull on the ground was tremendous and much more than the RCV 60SP engines which never reached much above 5,500rpm on 16x12 props. The RCV engines flew the model sedately, the motors will give a potential 20% boost to top speed, but more importantly 40% more thrust, which is why it felt so powerful on the ground. Fuselage after the engine out landing in perfect condition Wing in 3 parts RCV 60SP engines during original build Motors and ESCs Battery hatch cut into cowl and box Ready to fly again -
I have operated RCV SP engines for many years and as long as the instructions are followed with regards to using baffles to direct the air across the fins they are fine. You are repeating ancient problems ED. Second generation engines had redesigned [ larger] fins. It was a shame that the fins were not directed along the engine body as this would have been better for cooling but at the time this was not possible due to production restraints. The aircraft in my avatar a Seagull SNJ with similar cowl has an SP60 and just one baffle on the [ cool carb side ] [ a bit of ice cream tub plastic ] to direct air through the fins to exhaust side in the same way as Jon [ LASER] recommends for his new inline twin. I have no link to RCV engine other than user.
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I think when RCV were making the engine they initially recommended castor. I have the 2004 dated instructions here and the section on fuels is shown below. Once RCV were passed to weston uk weston naturally recommended their own fuel for the job and said no castor. Its a bit of a contradiction. In fairness, i wouldnt like to use castor in any engine either, and the recommended duraglo fuel is just awful. Also we used to recommend castor for Laser engines but time moves on. i will be using the laser 5 fuel i use in everything else once i get the engine back together.
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Can anyone share any info on these engines, I've seen them advertised in magazines but never read a review or heard anything on them, they seem an ingenious invention with the rotating cylinder and from what little i have read on them, because of the 2:1 crank to prop shaft gearing they are able to swing a 4 blade prop without any issues ? Is there anyone out there running one of these that can give a quick review ?
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Found the instructions for my RCV SP60, It is generic for 60, 90 and 120. Covers the usual running instructions and extras like the cooling baffle, heavy duty mounting method, dismantling and re assembly, timing the engine and recommended prop size's. Prop Idle Max RPM 60 16 X 12 1200-1500 5000-5300 90 18 X 12 1200-1500 5100-5500 120 18 X 12 1200-1500 5300-5600 Given the last set of figures covers an engine twice the size of my SP60 I find them rather odd. Bigger engines running at higher RPM's on same or similar size props seems wrong. I think it was a shame that RCV brought out the unusual innovative SP series first, and had the more conventional CD models been marketed first they would have had more success. P.S. sort you a copy if you want. John.
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Hi Andy, I have just come across this thread. From description on the opening thread you say it sounded like a sewing machine. Is this sound from cold or after the engine has warmed up. The reason I ask is I once had an RCV CD58 with the same problem a few years ago. I contacted RCV engines and spoke to someone, sorry I cannot remember his name, but he asked me what the serial number was and I recall it was in the low thousands and he asked what fuel I was using and I replied pro-synth 2000 which is the recommended fuel. He went into a lot of detail but basically with the earlier engine the cylinder liner was moving slightly hence the sewing machine sound. He said it could be repaired or offered me 25% discount on a replacement engine on receipt of my old one, I took up the offer and it has run faultlessly since although hardly used recently. Hope this is of some help Regards Robert
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Hi, Looking for a RCV 90 SP engine pref unused or little use. Series2/MK2 helical gears) I also have two BNIB RCV91CD engines available but would need the 90SP first. Thanks
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I used it over Humbrol enamel once, it went on well over the Humbrol without any issue. However, in service it was less than stellar, the paint / Poly-C was affected, softening and wrinkling and then rubbing off. This was with 10% fully synthetic fuel on RCV-60SP engines, the RCV SP engines were very wet engines in my experience, not sure if this had anything to do with the softening.
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I have a foot in both IC and electric camps with my 81" BT Mossie. It originally flew with RCV 60SP engines for a number of years although these were at the lower end of the acceptable power spectrum. I had an engine out incident a couple of years back and could not get quite back to the runway and the model landed in the rough pasture about 30ft from the edge of the runway. There was bad damage to the wings so I had to rebuild the wings and after the engine out I rebuilt it as electric power. Interestingly, the electric version weighs 17lb 12oz ready to fly, the IC version weighed exactly the same dry (without fuel). The RCV SP engines being the geared ones used 16x12 props running at peak 5,500rpm, so I have kept the same large props and chosen the motor KV appropriately. Hyperion ZS 4025-16 320kV motors with 16x12 APC E props driven by 6S 4000mAh batteries through HobbyWing Platinum 80A V4 ESCs. Measurements gave 6,450rpm at 22.3V with 47.5A, so about 1050W each = 2100W = 118W/lb. I am waiting for a gap in the wind and rain to remaiden it. RCV 60SP engines during original build Motors and ESCs during rebuild Battery hatch cut into cowl and box Ready to fly again
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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.
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Yes do have plenty of synthetic oil based fuels purchased for my RCV engines but was recommended by my LMS to use the caster oil fuel when I first started playing around with the Merco 61. Perhaps he had a lot of old stock in his shop which nobody else would purchase! Did not know any better at the time as I was flying electric models then. Did not give the fuel any thought as should have known better after spending weeks last summer cleaning up another old Merco of its burnt on residue.
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OK, now I’m wondering. I have wanted a Falcon for 60 years. I have a plan, a pair of wheels, but no time. But it’s on the list. I thought to do electric, as I no longer have IC engines small enough for this. I have worked out that a HobbyKing 4250 350kv motor will do the job, and I have batteries, speed controller, so no big outlay. And the nice low KV motor will allow me to swing an efficient big diameter prop. But, I do own an RCV SP60, (that’s the one with a 2 to 1 reduction gearbox) and wonder if there is any reason why I can’t use this, but use a large fine pitch prop to provide the urge. I don’t know which path I will follow, but would like to be well informed.
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Yes I guess 80FS is outside the 50-70FS recommended by the Black 5 designer - the engine outlines on the plan are described as 'Laser 50/70'. As for the RCV 58s; you are correct, they're not especially powerful. I know this because I did a 'real world' tachometer comparison between one of my RCV58s and an OS 46AX on the test bench. Using the same 12x6 APC prop in both engines (within minutes of each other, so the atmospheric conditions were identical), the OS gave 500RPM more at full throttle than the RCV. So the RCV probably only produces about as much power as a good 40-size 2-stroke. Edited By EvilC57 on 15/10/2019 10:53:53 -
Can anyone say that they have managed to get a 130cd or 120sp to pass an 82db noise test? If so how? Several have been tested at our club and they come nowhere near. I spoke to Weston who say that "any engine of this size will have a problem" This is simply not true in my experience. For engines made in the UK, to be sold with inadequate silencers, when it must be known they will face such testing just seems silly. Is it therefore expected that you must but an after market silencer to stand a chance?
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I am no expert on engines but could the squealing noise be a bearing slipping in the engine casting. Certainly on the RCV engine I recently did some work on the manufactures recommended using a bearing adhesive when fitting new bearings. Did not do this myself nor on a couple of other engines I have worked on this month, so don't know if this is a recommended procedure or even if this could be the issue you have. Sure the experts on this forum will be a better source of fault diagnosis but thought my suggestion could be worth considering (or not!).
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Forum members' new models: Let's see them.
EvilC57 replied to Paul Marsh's topic in All Things Model Flying
What do you get if you mix one of these (sorry about the image quality), a Black 5 designed by Dale Tattam around 2001: With one of these, a Dick Sarpolus 50 Caliber from around 1980?: You get one of these, a model with no name: Which had its maiden flight today ?: The story is that I had a couple of RCV 58CDs going spare: And was looking for something to put them in. The Black 5 was designed to take a pair of Laser 50-70s, so the RCVs seemed an ideal fit. However I considered the Black 5's fuselage to be rather ugly, with its angular 'stealth-like' appearance. A club mate suggested a website (can't remember which one now), which included a number of designs for twin engined models, including the 50 Caliber; although this was smaller and designed to take a pair of 25 2-strokes. So there begun a process which kept me busy for several months through the 1st & 2nd Covid lockdowns, of scaling the 50 Caliber fuselage plan up by 12%, and modifying it to fit the Black 5 wing, then building from scratch, and adding onboard glow starts, Tx switchable landing lights, strobes and nav lights. It also uses a complicated twin throttle mix, which allows independent throttling of the engines for starting and ground running, and is described here (my post September 7th 2019). By this morning, a number of technical issues had been fixed, including how far forward to cant the undercarriage legs to stop it from nosing over when power was applied, the weather was fine with favourable winds, and I'd finally run out of excuses (we've all been there!). So it had to fly... -
I see that these British designed engines are now being made in China. Do any forum members think that this exporting of technology is desirable? As there are fewer moving parts in these units, perhaps prices will soon drop below the level of the prices of ASP and Super Custom etc. 4 strokes
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You are right it is not possible to press it from above. Could be old fuel residue gluing it in some, a soak in glow fuel could help. Then back to the above, oven will warm evenly [ just do it when other potential users not around ] whack the whole casing square onto the block and bearing should drop out. Have used the heat method of bearing removal on many items like farm machines, Land Rover gear box's as well as model engines but as noted above not RCV CD engines. Others who have may have more info.
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I see in Alex Whittaker's weekenders column that we only have one domestic commercial model engine manufacturer now, PAW. I do hope it isn't true.
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Have an RCV58CD which occasionally sounds like a sewing machine when turned over with a regular clicking noise. Introducing oil to the intake seems to clear the issue but the noise quickly returns. Decided to investigate the noise as the engine has never been right after having its bearings replaced. Managed to get the crank case open after a bit of heating to the screws and resorting to the use of a dremel cutter on only two of them. Luckily no damage was done to the crank cover. As far as I can see without any real knowledge of RCV engines is that there appears to be a lot of play between the cylinder gear and the crank gear is this normal? Certainly rotating the prop back and forth produces a clicking noise from the gears but unclear if this is the noise I heard initially. Open to suggestions as to what to do next.
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Not great pics but these are the prototype RCV engines developed by Keith Lawes. Top is number 4 the engine this was built to a better standard by John Oliver and Ray Ivey. Second is 1st prototype made by Keith as were no's 2 and 3. Third is the 2nd prototype and first to have prop on the cylinder. Forth is 3rd prototype testing a set up more like the production engine.
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Thanks for the comments. They seem to echo what i have heard over the years in that some have an awful experience, and others a good one. Can the engines vary that much? JD8, i agree that something looks odd about the props and rpm's. Take the idle for example, 1500rpm is something i can achieve with a conventional engine and yet in this case it means the engine is idling at 3000rpm. Seems fast to me and i would not expect more than 1000rpm at the prop on a geared engine like this. Your 60 is also interesting as you are only running 5 inches of pitch in normal terms. Have you tried 12 inch pitch over the years? Using a laser 62 as a representative 60fs, i saw 10000rpm on 12x6 when i tested one a few weeks back. In RCV terms that is a 12 inch pitch at 5000rpm on the prop. Using a thrust calculator i get a hp match using 17x12 at 4950rpm. No idea if the power will scale like that, but its what i am using to guide my investigation.
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Well you could well be correct Martin as metric was not common in the UK in the 60's. Still measure my wood in imperial, but old habits will eventually die out just hope I have a few years left of using imperial. Just to be certain on getting the correct size have ordered the rear bearing from MF and all the others including the OS FS-52 bearings from Simply Bearings. Yes I have ordered a sealed bearing for the front Andy but suspect it could well spit out fuel due to wear on the casting. Not even sure the Merco will ever go in a model or be used. It was more along the lines of an experiment on taking engines apart given my recent experience with the RCV 58CD. Still interested in any thoughts on cutting gaskets using a laser cutter and cleaning burnt on residue. Do have some oven cleaner or is that way too harsh.
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Hi Manish, Yes, the entire cylinder does rotate, but it seems that in the early engines it moved up and down slightly when the engine warmed up as there was some play in the circlip holding the cylinder in place according to the chap at RCV, when this first happened with my engine I shut it down and checked it over as well as a lot of club mates did too and I started it up again and when it got warm the same thing happened again and again. I did not attempt to strip down the engine. Just contacted them for advice. Regards Robert
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