RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Yep. All the long shafts I've seen are 3/8"-24. I might feel better just having a bigger prop nut on there anyway. 5/16" always seemed a bit small when bolting up an 18" or 20" prop. After some checking of the plans and some careful measuring and figuring I think the long shafts will be fine "as is" for my twin project as long as I choose the spinners carefully and make the appropriate length spacers for the prop nuts. The blank "stub" on the end of the shaft will have to come off but the threaded portion should be fine right where it is...

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Here's a question for all you hardcore Ryobi vets. Once you get your engines set up and tuned and running well the way you like them (idle, top end, transition, etc.) do you find that you can leave them alone and not have to be turning needles every time you go to fly and the weather's a bit different or do you have to tune a bit every time you fly? I've been flying Ryobis for a few years now and it seems that more times than not I have to give the high speed needle a little nudge one way or the other to be goodon any particular day. Once done I'm good for the day. The reason Iask is up until now the needles have been very accessibleon any installation I've done. The next plane I'll be assembling and using Ryobi powerwill be a Gee Bee R2 and with the massive round cowl that's not easy to remove and thecarb right in the center of it behind the engine I'm kinda scratching my head as to how I'll do any quicktuning on a day to day sort of basis.Are all of these enginesa bit sensitive to weather or is it just mine?My string trimmers alwaysseem to run just fine without ever tuning them atall but I definitely don't ask as much from them asI do my airplane hot rods. If regular retuning is the norm does anyone have any good ideas how I can make that happen on my Gee Bee project? If it's not the norm them does anyone have any good ideas why I seem tobe doing it all the time?...

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Here's a little video of my latest Ryobi conversion on my 1/4 scale Affordaplane ultralight. On this day she was spinning an 18x8 Master Airscrew Classic at just over 7900rpm on the ground. Really pulls the goofy little plane around nicely compared to the earlier Ryobi I was using. Love these little engines...

www.youtube.com/watch

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Cool, and different type of airplane. (I'm an ultralight flight instructor.) Nice video too.

But man, I NEVER stay in front of an engine I am revving. I can't wait to get behind that prop once the engine starts.... Please be careful.

No offense intended, but I have seen props fly off, break, etc. and I don't want to see someone get hurt by one. Sometimes an engine "blows" and the sudden stoppage will spin that prop off so fast you can't believe it..... And sometimes Ryobis will "throw a rod".

AV8TOR

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Thanks for your concern but I was never in any kind of danger. Iwas wearingmy lucky hat... :-)

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

We tried to get the "powers-that-be" down in Aus here to see the same dangers. They insisted on the "prop to the crowd" approach because of the smoke and fumes and extra noise from the reving engines. ...mmmmm...
Thankfully it was changed later so one had to go to a safety section where neither such problems faced the crowd.

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Here's a little better video of my latest conversion project. Think I may actually be getting the hang of some of this 20th century technology (now that we're in the 21st)...

[youtube]http://www.youtube.com/watch?v=_ZS4PqiLanA[/youtube]

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

You need to find a different video editor program that doesn't force you to have music on the video?

I couldn't tell anything about your engine or plane for the music. I think it may be a good plane but couldn't really tell?

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Music is there by choice. Video is very bland without. Didn't make it strictly for engine noise...

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Just thought I'd throw this out there 'cause I think it's gonna help me in the future. I discovered something by accident last week that helped my tune-up a lot. The carburetors I've been using (Walbro WT-324 and it's replacement WT-891) have a regular choke butterfly in them. While at the field last week the choke butterfly screw came loose somehow and the butterfly blade fell out and it almost sucked the screw into the engine. I discovered that there's actually enough room to sneak a finger in between the carb and mount and choke it by hand so I finished flying that day choking it with a finger to get it started if it was cold. The neat thing is that removing the choke blade and rod entirely had the side effect of changing the tune-up a little. I had to open up the high speed needle almost 1/4 turn to smooth out and maximize the top end. I flew it the rest of the day with that setting and it ran very smoothly and seemed to transition from low to high speed better than it ever has. The next time out the weather was a little different and for the first time ever I didn't have to touch the needles and she ran smooth for four flights. I was very happy with it. I decided to leave the choke shaft/butterfly out of it so I removed the carb and filled the choke shaft holes with JB Weld to smooth out the air path a little and make it so I can get a more positive choke with my finger. I believe that on this engine with this carb when the choke was in place and open it was causing undue turbulence inside the carburetor and possibly even causing a bit of choking effect at wide open throttle. That would explain why I had to richen it up some after I removed the choke and might explain why it's been too sensative to changing atmospheric conditions. I'm guessing that it was choking it a little and I had it set a bit lean for that atwide open throttle then at slower speeds it was leaning out a bit and causingthe sensitivity and transition problems I had sometimes.I'm convinced enough that when I put together the engine for the Gee Bee I'm gonna eliminate the choke from the beginning and probably go with a primer bulb setup 'cause I won't be able to get a finger anywhere near the carb on that one. We're nearing the end of flying season here so I don't know how much more I'll be able to fly with this setup to expeiment but it definitely seems to be the way to go for me at this point...

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Some people use half of a small rubber ball glued to a long popsicle stick to choke their Ryobis.

AV8TOR

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Hi all,

I'm getting out of wet power and going all electric. I'm selling my Ryobis. Both the ones that are presented earlier in this forum are for sale. Check out the ad over at RCGroups. http://www.rcgroups.com/forums/showthread.php?t=1764328

Thanks, diceco

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Bummer. Sorry, but to me electric is not the way to go. I am on the verge of discontinuing all my magazine subscriptions because that's all they have any more; electric airplane coverage, even though a lot of them have "sister" magazines devoted to electric flight. For me, they are fine for park flyers and flying in the evening when you are done flying the "big iron", but that's about it. It is hard for me to believe how people invest all the money to go all electric, and then buy "noisemakers" to simulate real flight. Just my opinion....

Good luck on your sales though...

AV8TOR

RE: another darn ryobi post (ryobi performance modification, analysis and comparison)
 

Same here...soon as the music ,I lost interest. Need more close up video too...just want too help you make things more interesting!

Just found this thread. I am converting 2 Ryobi 31 myself. Recently 5 + years ago converted a Ryobi 31 and received parts from Peter Wacker from Wacker engines. He since has gone out of business. I liked the motor mount, prop adapter I received from him and wish I could find these replacement parts. Also got a Zama carb. from him that had done really well.

Now that Peter is out of business, what is my alternative ? Am looking at Dave Carr engineering. Possibly good alternative ?

Are you guys still flying the Ryobi 31 ? I love my original one and look forward to putting 2 more back in the sky ?

Yes. Carr Engineering or www.lambertsrc.com Those are the only ones doing conversion parts supply that I know about now, but they are both good sources.

AV8TOR

Jag engines www.jagengines.com has parts for Ryobi conversion.

Thanks Av8tor and Tidnab for the recommendations. I'll try these 2 sources. Can't wait to get t these 2 engines flight ready.

OK !!! Ordered 2 long shaft engine conversion kits from Jag engines along with the "Fancy Prop Nuts". Will need the prop nuts for my starter to work. Getting stoked up on this next build. Here's what I have in mind.........

Been flying the USS with my present Ryobi 31. What it consists of is a 45" long 3 1/2" square PVC fuselage (Fence Post Cover from Lowes) , swiss cheesed to save weight, has a 72" wing with 15" chord (ailerons included). Weight is around 13.5 lb. Flys very respectable.

http://www.rcuniverse.com/gallery/ga...6memid%3D16901

What I'm wanting to build on the next project is similar Using a 38" long 4" PVC fuse (swiss cheesed) , 60" wing and 15" chord. Trying to make one more agile, 3-D. With the smaller fuse and wing, hoping to save some weight. Do you think this plane is flyable ? or do you think it will be a waste of my time and money ???

I like the Fence Post Cover PVC fuse as it is; 1. Straight 2. can take a beating if needed 3. No construction time. I have made coroplast fuses, but I've found with the bigger-heavier planes, they can bend-warp a lot easier. A lot of my smaller planes are coroplast construction.

One further question before I close. What props are you using with your Ryobi's ? I've been using Dynathrust 18 X 6, 8, 10 with good results. Can't find Dynathrust new in that size anymore--though I did find and buy 3 off ebay yesterday. See that Master Airscrew has size in their "Classic" series. Is this a good alternative ?

Thanks

Cary

You might add a few square inches to the wing of your proposed plane or the wing loading may be too high. I generally consider 1000 square inches to be a good minimum size for conversion engined planes.

As far as props, prop it so that it turns no more than 7500 rpms on the ground. A good Ryobi will usually turn an 18 x 6 prop too fast. You want low pitch for 3D; you might even try a 20 x 6 in the brands you are speaking of... A Zoar 20 x 6 would be a bit too much load unless it is an exceptional Ryobi.

AV8TOR

Here's the USS I put together. 4" square fence post cover, 39" long. Wing is 62" by 16.75 chord. (including ailerons). Weight is 13 lb. 3 oz. Wing loading is 29 oz.

http://www.rcuniverse.com/gallery/ga...6memid%3D16901

Flys great !!! With the shorter fuse, makes more aerobatic. Have 15 flights on it.

Congrats! Looks great.

A comment and a question. Have you thought about going to electronic ignition to save weight and gain performance? Also, for 3D it would seem that your ailerons are a bit small. But congrats again on a successful project.

Note: Here's a good place to get ignitions. They are down to 45 bucks nowadays, and well worth it. www.extremepower.net

AV8TOR

Thanks AV8TOR for the comments.

Have not really thought about the electronic ignition for the Ryobi, but at only $45. , seems like a good way to cut down on weight. How does it increase performance ? I'm turning 7500 rpm on a MS 18 x 8 prop. Can I expect more ?

Not really looking at a USS to be a 3-D plane. Want it to fly realistically, with some aerobatics. Do have several 3-D planes to bash around.


http://www.rcuniverse.com/gallery/ga...6memid%3D16901

http://www.rcuniverse.com/gallery/ga...6memid%3D16901

Did I say that about the music ! :o

I really like electronic ignition, and in fact, out of a rather large fleet of planes, I don't have a single magneto equipped plane.

The benefits are lighter weight, easier starting, better idle, more power, and nicer looking as well. I can't give you an exact figure on how much more power, but you would gain some. You don't have the drag of the magneto aerodynamically, nor the drag of the magneto magnets as they make electrical power for the spark. Also, you can optimize the timing, which can result in net power gains too.

I have a Ryobi 31 in my Giant Tiger Moth Biplane. As usual for me, I have hopped it up by raising the compression, increasing the exhaust port timing, using a free flowing muffler, and a larger than stock carburetor along with electronic ignition. But it works, as it turns an 18 x 6 Top Flite wide prop at 8500 rpms! No, you should never turn a Ryobi over 7500 static or you risk blowing it up. In my case, I can't make a larger prop fit the spinner size for this particular plane, so I either don't use full throttle, or limit it to a few seconds at a time in this case.

AV8TORhttp://www.rcuniverse.com/forum/atta...mentid=2017412http://www.rcuniverse.com/forum/atta...mentid=2017411