Bipe recommendation for a Ryobi 31cc

Bipe recommendation for a Ryobi 31cc
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Bipe recommendation for a Ryobi 31cc - 5/5/2004 6:11:10 PM

Purple Pilot

Posts: 78
Joined: 1/13/2003
From: Nth Yorks, UNITED KINGDOM
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Hi,

I was wondering what bipes you guys are flying with Ryobi 31cc's, or similair gas engine, up front? I'm looking for something mildly aerobatic - loops and rolls sorta thing. It has to be under about 10lbs in weight without the motor tho' as we have a 7kg (15lb 6oz) limit here in England.

And/or can anyone recommend what sort of wing area would suit the 4lb Ryobi - is it still about 1200 sq. in. split between the wings? Or should it be more like 1500 sq. in. due to a bipes inherent inefficiency compared to a monoplane?

As always, many thanks for your advice!

Steve

Post #: 1

RE: Bipe recommendation for a Ryobi 31cc - 10/15/2005 1:40:49 AM

sscherin

Posts: 944
Joined: 8/17/2005
From: Castle Rock, CO, USA
Status: offline

I just got my Ryobi.
I"m thinking of getting the Lanier Ultimatte Pitts
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXX412&P=7

They clain 1112sq inches and 10-14lbs.

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Post #: 2

RE: Bipe recommendation for a Ryobi 31cc - 10/15/2005 7:00:53 AM

davewallace

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Joined: 1/15/2005
From: San Antonio, TX, USA
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Hi,
Get a Balas USA Phaeton 90 bipe. 70" span and should be just right. http://www.balsausa.com/kits/kit.htp?id=34&shopperid

Dave

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Post #: 3

RE: Bipe recommendation for a Ryobi 31cc - 10/15/2005 7:05:47 AM

Flak

Posts: 1476
Joined: 11/24/2002
From: Olathe, KS, USA
Status: offline

Purple Pilot,
I would think a bipe with a 70" WS would fly great with that engine. I have two Ryobi 31CC's on my 101" Ziroli B-25J Mitchell. Good luck.

"Keep 'Em Flying!"
Flak

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Post #: 4

RE: Bipe recommendation for a Ryobi 31cc - 10/15/2005 2:31:25 PM

Daryl Martel

Posts: 595
Joined: 2/10/2002
From: WinnipegManitoba, CANADA
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I don't want to rain on anybodies parade but know what you're getting into. I ran a Ryobi 31 conversion for a while. The power to weight ratio is very poor. Because of this, whatever airframe you hang this engine in should be light and have generous wing area. I had mine in a Lanier Stinger 120. The lesson I learnt from this is to stick with bigger name brand gassers with better porting. A friend of mine buys up old chainsaws and the like. I've seen the differences in design and quality between various brands. In my opinion, you get what you pay for.

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Post #: 5

RE: Bipe recommendation for a Ryobi 31cc - 10/16/2005 6:16:05 PM

carlosponti

Posts: 1083
Joined: 5/14/2003
From: Moore, OK, USA
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daryl: you didnt really answer his question. he didnt ask if you thought it was a good idea to use a ryobi. yes the comercial engine are a bit more powerful and lighter i think that is well known. for me its not about the cost but the fun of taking an engine that someone gives me and using it for something they would have never thought of. and believe me i have alot of motors now because everyone wants to get rid of a 2 stroke gas weed trimmer they think of me and my hobby. maybe its not about going cheaper but just a bit of sick joy of trying to get a weedeater to fly. the comercial engines rob me of this joy its mount fuel and fly. kinda robs me of the joy of tinkering.

purple pilot: i have wanted to put a weed trimmer engine in a biplane for a while and i saw a homelite 25cc go in a goldberg ultimate but he had to do alot of lighting to the frame. biplanes are always too heavy however i think that balsa usa phaeton would be about the best choice and look for ways to lighten without sacrificing strength in the air frame. make sure to place the fuel tank over the cg and leave soem room to help balance the plane with maybe putting servos in the tail. good luck and post what you can get done in the engine conversion section. might post questions there incase you have any there are alot of guys that have experience with that engine. i am by no means an expert but like i said earlier i like to tinker.

(in reply to Daryl Martel)

Post #: 6

RE: Bipe recommendation for a Ryobi 31cc - 10/16/2005 6:36:58 PM

davewallace

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Joined: 1/15/2005
From: San Antonio, TX, USA
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Hi Daryl,
For best results with your Ryobi, Use a 10 or 11mm carb. You don't want to use one of the cylinders that have compression dumping slots above the transfer ports. These exchange power for easier starting. Also the two ring pistons are a little better. Use a free flowing exhust with low restriction. All Ryobi's weight about four pounds, but they don't all produce the same power. For good performance you should get into the 7 thousand rpm range.

Dave

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Post #: 7

RE: Bipe recommendation for a Ryobi 31cc - 10/16/2005 8:05:41 PM

Daryl Martel

Posts: 595
Joined: 2/10/2002
From: WinnipegManitoba, CANADA
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Carlos - I think I answered the question. I'm saying consider how much weight you can afford to carry and the power you need for your style of flying. For me personally, the smaller gas engines don't cut it. Your results may vary. My feeling is that you have to get into bigger engines before the cost/benefit and power to weight ratios get better. The tinkering thing - I fully agree. It is very satisfying to convert something to RC use. I happen to have a pair of Kioritz (Echo) 61cc twins sitting here in the basement with me. I've got a Zenoah G-62 as well. I think you get what you pay for. A Ryobi is fairly gutless compared to some other (albeit much more expensive) choices out there. Dave - I'm done with the Ryobi. I gave it to my brother. I wouldn't even consider running one now. I'd rather go with a Zenoah G-38 or 45.

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RE: Bipe recommendation for a Ryobi 31cc - 10/16/2005 10:21:22 PM

tkg

Posts: 2202
Joined: 1/6/2002
From: Riverton, WY, USA
Status: offline

Biplanes and ryobi is a touch match. Flybaby's, PT-19 and Cubs do better. If its gotta have two wings look at the Lazy Ace series of plans.
Good luck

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To much power is just about right.

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Post #: 9

RE: Bipe recommendation for a Ryobi 31cc - 10/16/2005 11:25:30 PM

Ed Cregger

Posts: 7999
Joined: 1/31/2002
From: Ringgold, GA, USA
Status: online

This model was going to be my suggestion.

This model has lots of wing area to carry the weight. The Ryobi is not a power making demon, so
the model will have to fly "on the wing" instead of "on the prop". This would make a nice combo.

Ed Cregger

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Post #: 10

RE: Bipe recommendation for a Ryobi 31cc - 10/17/2005 2:18:17 PM

Jim Dines

Posts: 1409
Joined: 2/27/2002
From: Keller, TX, USA
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I have been flying a Balsa USA Phaeton 90 with a 25cc Homelite for over 6years. It is a very satisfying basic biplane that flies the basic manuevers. I moved the firewall back 1 1/2 inches for balance purposes, and I would guess the Ryobi would require another couple of inces back, due to its layout.

(in reply to tkg)

Post #: 11

RE: Bipe recommendation for a Ryobi 31cc - 10/17/2005 2:26:21 PM

carlosponti

Posts: 1083
Joined: 5/14/2003
From: Moore, OK, USA
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quote:

ORIGINAL: Daryl Martel

Carlos - I think I answered the question. I'm saying consider how much weight you can afford to carry and the power you need for your style of flying. For me personally, the smaller gas engines don't cut it. Your results may vary. My feeling is that you have to get into bigger engines before the cost/benefit and power to weight ratios get better. The tinkering thing - I fully agree. It is very satisfying to convert something to RC use. I happen to have a pair of Kioritz (Echo) 61cc twins sitting here in the basement with me. I've got a Zenoah G-62 as well. I think you get what you pay for. A Ryobi is fairly gutless compared to some other (albeit much more expensive) choices out there. Dave - I'm done with the Ryobi. I gave it to my brother. I wouldn't even consider running one now. I'd rather go with a Zenoah G-38 or 45.

i get all my engines for free. after telling them what i do with them people give them to me. i have now three homelite 25cc weedwackers, one homelite 26cc chainsaw, craftsman 32cc the ryobi and a 21cc featherlite.

i have a ryobi that i think is unusable after i got it apart.the ryobi i found has a wallowed out muffler bolt holes. it ran just fine but there is no way to mount a muffler.

the engine i look forward to working the conversion after i get freed form a plane i am building for someone is that homelite chainsaw. i plan on if i can putting it on my hanger 9 cap 232 1.20. i will put all the servos in the tail and the fuel tank over the CG and i think i should get it balanced. though the chainsaw is probably going to come in around a g26's weight.

(in reply to Daryl Martel)

Post #: 12

RE: Bipe recommendation for a Ryobi 31cc - 10/17/2005 2:54:35 PM

davewallace

Posts: 1402
Joined: 1/15/2005
From: San Antonio, TX, USA
Status: offline

Hi Daryl,
The Zenoah 38 and 45 are as close to a converted chain as you can get. They both are magnito engines and heavy. The Ryobi can be made to produce good power, it just takes more care in setting the engine,airframe and prop selection. I like the idea of setting up the plane so that it will take different engines. This allows me to experiment.

Dave

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Post #: 13

RE: Bipe recommendation for a Ryobi 31cc - 10/17/2005 5:27:54 PM

sscherin

Posts: 944
Joined: 8/17/2005
From: Castle Rock, CO, USA
Status: offline

Would the Balsa USA Phaeton 90 be a better match for a Ryobi 31 than a Lanier Ultimate Pitts?

The Pitts is 10-14lbs with a 60" wing and the Phaeton is 10-12 with a 70" wing..

Wing loading based on a 12lb plane would be 24oz/sqft for the pitts and 179 for the Phaeton.

Hmm I guess I answered my own question.. I guess the Phaeton would be a little more lively but would the Pitts still fly ok?

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Post #: 14

RE: Bipe recommendation for a Ryobi 31cc - 10/18/2005 12:08:35 AM

Jim Dines

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From: Keller, TX, USA
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The Pitts is a "muscle Plane", the Phaeton 90 is not. You would want more power in the Pitts, despite it being smaller, to fly the Pitts to it's design style. The Phaeton is more like a version of some golden age bipe. I recommend it.

(in reply to sscherin)