AnthonyH

My Feedback: (16)

I am starting a Ryobi 2 ring short shaft conversion. It acutally came from a Bolens trimmer. I wanted to know what weight you guys were ending up with after conversion. Also, what prop and rpm are you getting from it? I have seen guys posting 7000 with 16x8 props and that does not sound like much.

What conversion are you guys using most? This will probably end up on a Robinhood 80".

Edwin

My Feedback: (2)

Dont recall the weight on mine. But I get 6700 rpm with an 18x8. Like it a lot. Gives good lively sport flying and has great pull. I fly it in a 82" Bandito Grande. The rpm isnt important to me, I go by how it flys. Not always a direct correlation. Just my opinion.
Edwin

AnthonyH

My Feedback: (16)

That sounds respectable. Is yours a two ring version? Does the two ring version produce much more? I have a Stihl that is turning 8000 with an 18x6 and did not want to waste time and money on the Ryobi if it did not come close to the Stihl. I can get more Stihls just as easy as Ryobi. My Stihl comes in at 60oz ready to fly.

Edwin

My Feedback: (2)

Mine is an 8 year old 1 ring worn out old engine with 2 flying seasons on it. Its one of my regular flyers. I have 5 ryobi's, just 1 running right now and 1 more not finished converting. The others are waiting. Got all of them free from neighbors and friends. When they dont run any more, they just buy a new one. They are easy to fix once you've done the first one. Should be true for any brand. A mechanic/machinist friend of mine (drives a 600hp hotrod to work every day) did some work on a ryobi and CLAIMS to have hit 9000rpm with an 18x8. I told him I dont want that engine in any of my planes. Scared it might come apart. So far its got quite a bit of bench time and seems to be holding up. Told him I need to witness this. It was a refurbished engine from harbor freight.
Edwin

CrazyHerb

My Feedback: (1)

I'm flying a twin-ring version (www.wackerengines.com parts), it's 4.4 lbs, swings a Bambula 18x8 around 6,700 and gives me about 15-16 pounds thrust.

Here's a pic of mine on a cheap bathroom scale (no carb, no prop)

http://www.crazyherb.com/PLANK/IMG_1253.jpg

Best upgrade is the wackerengines muffler....free-breathing....if you don't mind a little more noise...

I have 25 meg video of it on my 17 lb Big Pink on my web site.

Good Luck!
CrazyHerb

buck1856

My Feedback: (49)

heres a pic of my engine thats for sale here on RCU in the gas engine listing.it weighs 70ounces as pictured with stock exhaust.i had a18x6 MAS 4 stroke black classic prop with stock carb and was getting 6400 rpms.i live at 3000 feet above sea level.this was regular gas at 40:1 mix.about the same thrust as earlier mentioned in this post,its been a while since i tested it.

AnthonyH

My Feedback: (16)

I think if you could cut out every other fin on the engine it would lose a lot of weight. I don't think it needs that much fin area, plus it would allow air to get in there easier. Looking at the DAs and 3Ws, etc. they all have large gaps between very thin fins.

Buck, who made the standoff mount for you, or did you do it?

netsurfer

IMHO the thin fins allow for a bigger gap without reducing the surface area for cooling purposes. Dont forget if you break out every other fin, you are effectively reducing the surface area by half.
All i'm saying, is be careful.. even with the forced air from the prop it may not be enough if you half the area. Maybe pick up a cheap IR thermometer and let us all know how the temp is affected if you do.

Just my $0.02

Pete