Pit-Viper 1

My Feedback: (12)

mine has about 5-6 thru it now and it gets quieter each tank so I would say not good. The only thing i can think is that it may have gotten warm.

Shane

thekosz

I just rcvd my rcv 91-cd, and have run a couple of tanks through it, all I have to say is what a great engine, started first spin, ran great, seemed like it had more than enough power, followed RCV's Running in instructions, Ran for 15 min, and 15min cool down time, fired it up, set the high end, then set idle, very quite compared to OS & Saito, very distinct sound(average joe may not be able to distinguish) but our flying club has many 4 strokes so I noticeed the minute differences. I will continue to post when engine has had more run time, first in the CG super chipmunk, and then moving it into the new great planes Super Skybolt ARF when it arrives.

RCV Engines

Hi

No, this is not normal. Has the engine had an impact on the prop at all? If so, you could tighten up the prop and try pulling it. This can sometimes work.

Alternatively it could be a loose bearing, in which case it would be better sending it to our US service centre.
If you could email me with your serial number, name etc and I will issue you with a warranty authorisation number.

Best regards
Laurenne

thekosz

I recently got my 91-cd and runtime was a big issue for me, I am getting roughly .5 ouncez/minute, 16oz tank at 6000rpm lasted roughly 45 min, unbelievable runtime, compared to most 4 strokes that are getting 1 oz, 1.5 oz/ min, hope this helps.

Pit-Viper 1

My Feedback: (12)

Well finaly got some time in the air after a ton of CG changes. This motor does not produce the rpm that it states it should. I am using Omega 15% caster blend w/ APC 14x7 and only getting 7900-8000 rpm's. This motor would barely fly my spit at just over 11lbs. I will continue to run it as it has just a gallon through it now and needs more time on the motor. Just wanted to note this for future references if needed.


Shane

RCV Engines

Hi pit-viper

Either there is a problem with your engine or I would go with a smaller prop. A 14 x 6 should give you around 9200, a 14x 8 on the other hand only gives around 7800. I don't have the figure for a 14x7. Firstly I would try a 14x6 and see what rpm you achieve.

If you don't achieve around 9000 - 9200 then I would say there may be a problem with your engine.

If however you are achieving this, then it may be that it is not suitable for your model. What engine does your kit recommend? Our engine is equivalent to a .91 4-stroke or a .60 2-stroke. Although many modellers do use the engine in 11lb models, this is slightly on the heavy size for a 90 4-stroke so performance may be marginal.

Let me know what rpm you get on a 14x6 and we'll work out the best course of action from there.

Best regards
Laurenne

Pit-Viper 1

My Feedback: (12)

OK will do. Thanks Laurene

Shane

p61widowrc

My Feedback: (1)

Hey thekosz,
I just ran my 91-sp for the second or so time. The first two times was just to start it and test out my starting procedure. This time I ran it for a little over 15 minutes and I am amazed at the amount of fuel it ran on. I totally agree with you on how little fuel it runs on. I don't get alot of slobber or oily mess on the engine. I was doing a double take the whole time trying to see the fuel go down on my test tank. I sure hope this engine proves out. I'm putting together a VQ P 61 using two of these babies and right now I am impressed. I used an electric drill with the hex driver just to turn it over a few rpm just to loosen the engine up. After that I put the glow to her and started it by hand flipping the prop. I really am looking foward to getting this engine in the air, but I've got a long way to go.
Take care everyone,
Bob

thekosz

That is strange, another member of our club just purchased a 91-cd and it runs great on a 14x6 and on a 12x9, personally I am getting about 9400 - 9600 RPM on a 14x6 APC, idle is reliable at 2100-2200, with glow it idles nicley at 1700-1800 RPM, How much run time do you have on that engine. Oh by the way the fuel I was using was Powermaster 15% nitro with 18% synthetic oil mix 6% of which is castor blended

thekosz

Heey p61widowrc, thats great. keep letting me know how your sp series is as it could be my next purchase for a future me-109 project.

Pit-Viper 1

My Feedback: (12)

I got about 2hrs. total on it with 30min of that in the air. I got a question, the very first time I touched the low end needle on the .91cd, I was turning it in to see where it was set at. After about 2 or 3 turns in it just wasn't there anymore, the needle literally fell into the barrel of the carb. Now i've tuned ALOT of motors in my time, but this was new to me. Now the needle had never been touched until this point, factory setting. Ran so good I just never messed with it, was slightly rich. I actually havn't run it since, I took it off the plane until I figure this out.

Shane

p61widowrc

My Feedback: (1)

Hey Kosz,
Ran the SP-91 again last night for about another 20 minutes. Checked with my tach this time and could get it to 5700 to 5800 top end and the best I could see was about 1300 to 1400 on the low end. I don't know how long it would go on idle, but I hit the throttle a couple of times and the engine responded to full RPM each time. Now I'm running this engine on a test stand out in the open air. I don't know if the performance will be different once it is cowled. One of the things that I noticed is the lack of oil slobber that I normally associate with a 4 cycle. It seems to be a cleaner engine. By the way, I'm running this on Sig's 4 strole fuel which is 15% nitro with 16% oil, half castor and half syn. My needle valve has been the only slight problem. It wanted to rotate. I unscrewed it and pushe the tension spring in a little and put it back in and for now that seemed to work. I'll keep everyone posted as I run the engine.
Take care,
Bob

Edge3644

Forget about this british piece of junk. The '"best" they can create is "fish & chips", which also kills they admirers.

thekosz

June 25, 2006, today was the maiden voyage for the chipmunk and 91-cd (it is a used plane new motor but maiden voyage for me), after practicing some taxiing and some speed burst runs I was finally ready, the plane ways approx 8lbs on a bathroom scale and the motor had more than enough power, she took off at just over a 1/3 throttle and climbed out nicely, at just under half throttle she had lots of jam, I only flew for about 5 min or so due to the aircraft wanting to bank to the right hard, but during that time at just under half throttle she was able to climb perfectly, I am assuming under full throttle she will have unlimited vertical, engine noise was a minimum extremely quite, at an 1/8 throttle she came in beautifully. Will post more when trims have been readjusted.

RCV Engines

Hi Pit-Viper

To get back to the factory settings for the idle needle, screw the needle in fully with the throttle open and then unscrew 3 1/2 - 4 turns

I hope this helps
Best regards
Laurenne

Pit-Viper 1

My Feedback: (12)

The point of my last post was that I cannot screw the needle in all the way as it will fall into the carb. So I tried to take it out by unscrewing it and it does not want to come out this way. Is this carb a new design? Normally you turn it clockwise to lean (close) and vice-versa to open and remove needle. This is completely backwards, lol


Shane

w8ye

My Feedback: (16)

You have to remove the barrel from the carb and get the needle started back in from the inside.

Don't screw the needle all the way in with the throttle all the way open.

kinverflyer

My son has a RCV 91CD in his YT International (ESM) Spitfire, take off weight is 14lb using a 14x8 Master Airscrew, slightly extended take off due to higher pitch but flying, I have a Laser 120 in my 13.5lb BF109 turning a 15x8 Master and I struggle to keep up with him. My experience with these engines 100% reliability, I dont think I have had to touch the needle valve after the running in period on any of them, well impressed.

RCV Engines

Hi PitViper

Sorry, there have been two carburettors used on the 91CD. You have the original carburettor which you unscrew fully and then screw in 3 1/2 - 4 turns to get back to the original factory settings. This is only a starting point.
If you are having problems removing the idle jet you can use a small implement to feed it back & unscrew at the same time (counterclockwise), or use w8ye suggestion.

Kinverflyer is correct though, once the idle is set, there should be no reason to change it unless you change the size of prop or fuel used.

If you have any more problems PitViper please let me know and we will sort out a carb for you.

Best regards
Laurenne

Pit-Viper 1

My Feedback: (12)

Actually I think thats all I needed to know. I got it fixed right away, just was'nt sure about the settings. It runs fine other than not get the RPM desired. I'm not discouraged by this motor at all, It runs great. I will put it in one of our trainers and get a couple gallons or so on it. Then try it in my Spit again. Right now though, at just under 14lbs. It barely flies it, need that extra rpm. I wish there were some studies using higher nitro content, I usally use 25% in all the other 2-4 strokes with excellent results, but with this cylinder design I don't want to void the warranty. More testing I guess, not like that is a bad thing though.


Shane

RCV Engines

Hi Shane

I'm glad it's sorted.
The engine technology does mean that power on the RCV91CDs does vary from engine to engine. Although additional running should increase the rpm further, a 14lb model is really too heavy for 'normal' RCV91CD engines.
Perhaps you should consider getting an RCV130CD when they come out at the end of the year...that would be perfect for your Spitfire.

Happy Flying
Laurenne

Pit-Viper 1

My Feedback: (12)

Wow, a 1.30CD? That should do the job. Any info on them available yet?

Thanks Shane

sedrick

I would be intersted in a list of warbird ARF's suitable for the RCV 90SP. I have one on the shelf but have been flying giant scale for the last few years. I am losing my pick up truck to my son so I have to scale down.

RCV Engines

Unfortunately we have no specifications available yet. As soon as these are published I will put a note on the RCV technical support area on this forum, as well as highlight this on our website.
What I can say is that it is similar in height to a .70 4-stroke rather than a 1.20 4-stroke.

With regard to ARFs suitable for the RCV90SP, really you could opt for any which suggest a .60 2-stroke or .90 4-stroke. Check out the gallery section of our website to see some examples from RCV users - [link=http://www.rcvengines.com/gallery/rcv_gallery_90sp.htm]http://www.rcvengines.com/gallery/rcv_gallery_90sp.htm [/link] . In the future I will look at adding a list of warbirds to the website. If you have any queries regarding a specific model, we are always happy to give advise.

Best regards
Laurenne

p61widowrc

My Feedback: (1)

Laurenne,
How do you read the serial number of the engine? There is a 2 digit number and then a 4 digit number on the SP 90's I have. What does the numbers mean. I've seen some engines on ebay and I asked for the serial numbers. If I see one on ebay, I want to make sure it is new and can be registered for warranty. Thanks.
Take care,
Bob