av8rdavid

Hello everyone,

I finally decided to leave the $20.00 a gallon glow engines and go GAS....
I have been looking into something small and economical to power a Great planes .60 Cub and the ryobi was suggested by a friend of mine.
The plane calls for 2-stroke .60-.90 cu in (10-15 cc) or 4-stroke .70-.91 cu in (11.5-15 cc) in GLOW power, but i'm wondering if the Ryobi 31cc would even cut it?
Any info on these Ryobi engines would be great!

Dave

Jake Ruddy

My Feedback: (40)

I dont know the wing size on that plane but considering the size of engines it calls for I think it's too small for a gas engine.

Gas engines don't put out as much power as glow engines do and they weigh more. If you try putting a gas engine on too small of plane you end up with a heavy underpowered plane. Really a 25% (quarter scale) is about as small a plane that you want to put gas on. There are even some 1/4 scale planes that do not work well with gas.

soarrich

My Feedback: (98)

I agree, you right at the bottom edge of what works with gas. I looked at the Tower ad for you Cub, if it's the 90incher I'd say go for it. The Ryobi would have the power, mine turns a 16x8MAS 7000rpm and flies a 16 pound plane, though most people put them in about 11 pound planes.

Charley

My Feedback: (2)

You might want to look into the BME SuperTigre gas conversion. It's a Chinese glow ST converted to gas with a needle bearing rod, gasser pump carb and electronic ignition. Ought to be a good fit for your Cub.

Another thing you might consider is to put an electronic ignition on a .90 and run it on straighr alky fuel. That gets your cost down to ~$5 a gallon at current prices.

CR

av8rdavid

Its a 90 inch wingspan and weighs about 14lb (give or take)....The previous owner had a zenoah g26 (I BELIEVE) installed and said it had great power.
The Zenoah engines look GREAT, but the price is wayyyyyy too steep for what i can afford. Thats why i was exploring the option of the ryobi 31cc....I did notice the trimmer the ryobi 31cc comes from is DISCONTINUED!!!! Is there any other replacement to the RYOBI that conversions have been done with things like double piston rings and lightened flywheels?

soarrich

My Feedback: (98)

There's one on ebay `````````` now. I really like them because they are rear induction and rear exhaust, makes for a neat installation.

I've got three so I bought some aluminum to make motor mounts out of, I have extra so if you need a motor mount I could make you one for $10. I'm not in the business, you just have to buy more stock than you need, they don't sell 3 inch pieces. I have 2 and 3 inch stand off, I made a mount for my plane using the three inch which gives you plenty of clearance for the muffler. I'm now putting my second Ryobi into a BalsaNova, for this one I'm using a 2 inch stand off which clears the muffler, but not the muffler's mounting bolt's heads, so I'm either going to just relieve the firewall where the boltheads are or make an adapter to use a $3 lawn mowwer muffler.

Moderator removed reference number to item on Ebay . . .


sorry, my bad.[&:]

Charley

My Feedback: (2)

Have a look at this:

http://cgi.ebay.com/31cc-Ryobi-Gas-E...QQcmdZViewItem

CR

tkg

My Feedback: (1)

The Homelite 25/30 is lighter than the Ryobi and the 25 will turn a 16x8 in the 8000= range. The Ryobi is easier to convert, but the Homie can be done with basic tools and a grinder.l

Charley

My Feedback: (2)

I posted a link to an ebay auction wherin the vendor was selling refurbed & converted 31cc Ryobi engines for ~$85. The moderator deleted it because it referred to a specific ebay sale.

Anyhoo, they are on there, as well as some others, new for ~$200. There's also a used one on RCU buy and sell for $100.

I hope this is oblique enuff that it won't be moderated in some fashion.

Cheers,

CR

w8ye

My Feedback: (16)

Charlie,

You did good

captinjohn

That e--y place had some 25cc engines that appeared to be Mac brand for $26 dollars. Hope this is not to oblique. My other posts did not last long! Capt,n

m_keeven

I have that plane with a Zenoah G23 on it. The plane builds as we used to say "like a brick outhouse". It builds really heavy. I have a couple of Ryobi 31cc two cycles that I converted but haven't mounted yet. One is on CH ignition, the other uses the flywheel. I plan on putting one of them on a Dynaflite PT19 that I hear they fly really well. The Ryobi is too big and heavy for the Cub. But I doubt that it would fly on anything less than the G23.

aero nut

as far as your question is concerned!!!! do the Ryobi it will fly that cub perfectly without lack of power just make sure you get a 2 ring version with a two needle carb, remove stock muffler or gut out the insides of it, and if you wish to save weight convert it to GAS/GLOW!!!!

captinjohn

If you are in the building stage....try to get some weight off the tail section. Try to get some sort of balance before you cover it. Capt,n

av8rdavid

Hey,
The plane was already built and feels as if it already has a weight in the tail section...Previous owner had a G26 on it and said it pulled great.
Still looking for a descent ryobi 31cc double ring, etc for this bird.

flyjoe540

try harbor freight tools . or big lots sometimes has them or homelite blowers . good luck

KI8FR

I have that plane and I have a quadra 35 on mine and it works good for me.. the 35 is a little big for it.. I was going to put a 25 or a 31 on it. but the plane works good with the 35 and I just did not want to put work in a plane that is working... lol

sscherin

My Feedback: (1)

Hey guys.. isn't this still the ryobi motor?

http://www.harborfreight.com/cpi/cta...emnumber=55008

flyjoe540

yep , thats what we call a ryobi .I bought 3 last summer . all were 2 ring engines.

av8rdavid

So basically to make this the "Ultimate Ryobi" we would have to replace bushings for ball bearings, lighten and balance flywheel, add pitts muffler ,add a prop hub and aluminum engine mount?
Am i missing anything else?
All that would make a ryobi 31cc cost almost as much as a Zenoah!!!!hahaha!

Rcpilot

My Feedback: (78)

No.

You need a mount and a prop hub to turn it into an airplane engine. Thats all.

Now if you want to get fancy, you can put an aluminum muffler on it. You can change out the magneto for an electronic ignition unit. You can even machine the fins off the flywheel if you so desire.

But the only thing you NEED is a mount and a prop hub.

You can get that stuff for about $15.

You can buy a brand new weed eater from Harbor Freight and have it shipped to your fornt door for less than $70.

Let's see:
$60 engine + $15 prop hub and mount = $75 engine that will outlast any glow engine on the planet and run on 1/10th the fuel.

The 700R engine is a short shaft--the one listed in the link sscherin provided
The 725R is a long shaft

Both work fine for airplane engines. They just require different prop hubs.

aero nut

you don't have to change the bearings

moparcolt

My Feedback: (2)

Mine has roller bearings on the crank (stock) and turns a 18x6 zinger prop at about 7500 RPM and I am working on getting some more RPM out of it!
It is a single ring engine, modified a bit but a stocker will turn a 16X8 prop just as fast I have tried it.
I took one of mine out of an old worn out trimmer, and the other was new but both run fine.

Have fun with the project and drop me a line if you have any questions.

Rcpilot

My Feedback: (78)

Just keep your Ryobi under 8000RPM on the ground and you should be fine for many many years of service. I don't know if anyone is running them at 8000RPM+ over the long haul, but I know they will run forever at 7500RPM.

Bump the compression, add a better set of rings to it, increase the exhaust duration, replace the stock muffler, bend the reed stop out and add a bigger carb-- and you'll need more prop. These engines respond very well to "tuning".

Just be aware, they don't hold up long when you push them past 8800RPM. Did that last summer. It was spectacular. Ran like a scalded cat for about 2hrs run time. Then it pretty much exploded. [sm=lol.gif] It was hilarious. Most fun I've ever had in the hobby. I don't know why, but myself and a friend have a sick enough sense of humor that we blew one up last summer and it was good for at least 15 minutes worth of gut laughing. They are cheap engines. They run good in stock configuration. They start running GREAT when you get one of them around some carbide bits, polishing wheels and a lathe. Modifying and runnning one of them to the point of failure was quite an education, as well as hours of enjoyment. I'm no engine guru, but I do love tinkering with engines. I actually had no idea one of these would run as good as it did when we finished cutting and grinding on it. It was quite a surprise.