Ryobi 31, what prop
07-24-2002, 07:17 AM
#3
Senior Member
Join Date: May 2002
Location: Northern,
OH
Posts: 387
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31, what prop
What the engine does on the bench when the prop is effectively stalled can be misleading. What I've found with my Ryobi is that when there is little or no load on it, it 4strokes.
Smaller , lower pitched props sound great on the ground, but once the plane is flying straight and level and the motor unloads, it may 4 stroke..alot . I started with an 18x6 at around 7100 rpms. Again...great on the ground, but full throttle in the air and it 4 stroked...until I climbed or did a loop or something to put a load on the motor. Soooo...went to an 18x8, this seems to be what alot of guys are running on their ryobis. It did better, but I finally settled on an 18x10 prop turning about 6400 on the ground. It runs great and 2 strokes thru 98% of the throttle range. It normally only 4 strokes now when I'm coming out of a loop..and that sounds kind of cool ;-)
My head temp with this prop is around 210 degrees F. A little warm..but so far it 's doing great. Heck, I'd say it probably gets alot warmer than that inside the plastic cowl as a weed whacker. Also, I tried every trick in the book to get rid of the 4 stroking; pressure line from the diaphragm hole to the carb, then to the inside of the fuse....tweaking the needles every which way. My understanding is that this is just the nature of this type of motor...no load..it 4 strokes. So give it a good sized prop to fly on. I didn't really bench run my motor..only enough to be sure the carb was set and it ran reliably...then into the air she went. Remember, it's a weed whacker..not a DA150 ;-) So bolt her on..and go fly !
Smaller , lower pitched props sound great on the ground, but once the plane is flying straight and level and the motor unloads, it may 4 stroke..alot . I started with an 18x6 at around 7100 rpms. Again...great on the ground, but full throttle in the air and it 4 stroked...until I climbed or did a loop or something to put a load on the motor. Soooo...went to an 18x8, this seems to be what alot of guys are running on their ryobis. It did better, but I finally settled on an 18x10 prop turning about 6400 on the ground. It runs great and 2 strokes thru 98% of the throttle range. It normally only 4 strokes now when I'm coming out of a loop..and that sounds kind of cool ;-)
My head temp with this prop is around 210 degrees F. A little warm..but so far it 's doing great. Heck, I'd say it probably gets alot warmer than that inside the plastic cowl as a weed whacker. Also, I tried every trick in the book to get rid of the 4 stroking; pressure line from the diaphragm hole to the carb, then to the inside of the fuse....tweaking the needles every which way. My understanding is that this is just the nature of this type of motor...no load..it 4 strokes. So give it a good sized prop to fly on. I didn't really bench run my motor..only enough to be sure the carb was set and it ran reliably...then into the air she went. Remember, it's a weed whacker..not a DA150 ;-) So bolt her on..and go fly !
07-24-2002, 11:26 AM
#5
Senior Member
My Feedback: (1)
Join Date: Jan 2002
Location: Sault Ste Marie,
ON, CANADA
Posts: 758
Likes: 0
Received 1 Like
on
1 Post
Ryobi 31, what prop
Think Atom is correct......a 16x8 or 18x6 is min,and keeping the revs down with an 18x8 is about perfect after break-in.I beleive in breaking in the Ryobi like any other two stroke and use 32/1 petro based oil for the first gallon or two,then go to synthetic at 40/1 and fly the snot out of it!
I use the CH ignition on mine for weight considerations,and cause the stock flywheel often gets in the way in fully cowled installations......Im also planning a twin project using two of them and right now looks like its going to be a twin Otter of around 130" span......
I use the CH ignition on mine for weight considerations,and cause the stock flywheel often gets in the way in fully cowled installations......Im also planning a twin project using two of them and right now looks like its going to be a twin Otter of around 130" span......
07-24-2002, 02:34 PM
#6
Member
Ryobi 31, what prop
I to have done the conversion.It's never been in the air yet but the motor seems to be more at home with bigger wood.On the bench I'm using an 18x 6-10 zinger.......6200 rpm.
It's just a stock conversion with a F. Bowman ring.
Now if that picnic table that it"s bolted to had an elevator...................HUMMMMMMMMMMM
It's just a stock conversion with a F. Bowman ring.
Now if that picnic table that it"s bolted to had an elevator...................HUMMMMMMMMMMM
07-25-2002, 06:10 PM
#7
My Feedback: (4)
Join Date: Feb 2002
Location: Silver Lake, KS
Posts: 388
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31, what prop
I converted a pair of them last summer for use on my Ziroli B-25. I ran them a number of times with a 16-8 two blade prop and then changed to a 16-8 three blade Graupner which is turning 6700 - 6800. I'm not looking for all out speed, just a way to fly the 25 which is about finished and ready for a test hop soon. The engines and B-25 project can be viewed on my homepage.
I like the conversion of the 31cc and will build me a large Ugly Stick to fly one on as well.
I like the conversion of the 31cc and will build me a large Ugly Stick to fly one on as well.
07-25-2002, 06:21 PM
#8
Ugly Stick?
Now theres an idea! That would make a great beater or work the bugs out plane. I got some plans from the net a while back that I scaled down to a 30" ws. Just got to scale it up to 31cc (~1.8 ci ??) size. How big a wing span you figger?
Edwin
Edwin
07-25-2002, 10:28 PM
#9
My Feedback: (4)
Join Date: Feb 2002
Location: Silver Lake, KS
Posts: 388
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31, what prop
Edwin, I was thinking in the 90 inch area. I have an old Midwest .60 that still flys and I enlarged it ( and changed the looks a bit ) up to approx 81 inch and made a twin out of it. I'll use the same plans and go on up in the 90 inch area for the Ryobi version. Single Ryobi on this one.
07-29-2002, 01:24 AM
#10
Member
My Feedback: (1)
Join Date: Jun 2002
Location: Western North Carolina
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Ryobi 31, what prop
You guys can see what the Ultra Stick does with a Homelite or Ryobi at
http://webpages.charter.net/rsengineconversions/
These guys really know their stuff and they can provide complete motors or conversion/upgrade parts. Look em up.
I have one of their homelites on my Ultra Stick and it runs like a scaleded dog.
Big al
http://webpages.charter.net/rsengineconversions/
These guys really know their stuff and they can provide complete motors or conversion/upgrade parts. Look em up.
I have one of their homelites on my Ultra Stick and it runs like a scaleded dog.
Big al
07-29-2002, 10:27 PM
#12
Member
Ryobi 31, what prop
Just ran my ryobi With a 18-8 APC............RPM was 7100 .But it developed a strange little "BUZZING" type vibration.Going back to a 18-6-10 zinger only 6200 RPM but the engine seems smoother.Can't expect to much . I mean 49 bucks you can't expect much more than wood shed developement.Soooooo it's great for what it is!
Riley
Riley
