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Need advise choosing a motor.
Page 1 of 1
Need advise choosing a motor.
A friend gave me a serious stunt plane originally fitted with a .61. I'd like to use a 4 stroke. It has a 56" span. What size? .70?


Cajun66- Silver Member
- Posts : 75
Join date : 2014-01-03
Age : 48
Location : Baton Rouge, Louisiana
Re: Need advise choosing a motor.
The usual conversion was if it used a 60 2 stroke you would want a 90 to 120 size 4 stroke for the same power. OS and Saito both make 80 size 4 stroke engines. IIRC the 80 uses the same case as the 70 just bored out.
Jason_WI- Top Poster
Posts : 3123
Join date : 2011-10-09
Age : 47
Location : Neenah, WI
Re: Need advise choosing a motor.
4 strokes can be used for CL stunt, but out of the box they won't work right. It will take some fiddling to make it reliable.
I don't want to steer you away from this forum, but if you are really serious about going 4 stroke then you might want to visit Stunthangar as they have a board solely dedicated to 4S applications.
Those guys can be a little proud over there so go in with thick skin.
Another thing to keep in mind is the weight. The 4 stroke is much heavier. Seeing that the plane is built it may be best to put a .60 back in it as there will be less mods.
With a Span of 56" it sounds more like a .45 sized plane.
Ron
I don't want to steer you away from this forum, but if you are really serious about going 4 stroke then you might want to visit Stunthangar as they have a board solely dedicated to 4S applications.
Those guys can be a little proud over there so go in with thick skin.
Another thing to keep in mind is the weight. The 4 stroke is much heavier. Seeing that the plane is built it may be best to put a .60 back in it as there will be less mods.
With a Span of 56" it sounds more like a .45 sized plane.
Ron
Cribbs74- Moderator
Posts : 11880
Join date : 2011-10-24
Age : 49
Location : Tuttle, OK
Re: Need advise choosing a motor.
That's a beauty, Matt. What's it called?
Rusty
Rusty
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RknRusty- Rest In Peace
- Posts : 10869
Join date : 2011-08-10
Age : 67
Location : South Carolina, USA
Re: Need advise choosing a motor.
AMA# 6964 is Gil Causey
He goes by "bootlegger" on Stunt Hangar, shoot him a message and tell him you have his old plane. He can tell you what it is and what engine used to be in it.
Ron
He goes by "bootlegger" on Stunt Hangar, shoot him a message and tell him you have his old plane. He can tell you what it is and what engine used to be in it.
Ron
Cribbs74- Moderator
Posts : 11880
Join date : 2011-10-24
Age : 49
Location : Tuttle, OK
Re: Need advise choosing a motor.
RknRusty wrote:That's a beauty, Matt. What's it called?
Rusty
I'm confused about that, been looking for a while online to see if I can ID it. The wing looks like a Nobler, but that stab/elevator is throwing me for a spin.
Ron
Cribbs74- Moderator
Posts : 11880
Join date : 2011-10-24
Age : 49
Location : Tuttle, OK
Re: Need advise choosing a motor.
4 strokes are cool but add complexity, weight, and in my experience are more thirsty (some will debate this assertion)

on left is Magnum 1.2, then a Super Tiger .90 then a ASP .061
Note that the ST .90 is nearly same weight and dimensions as the .061 thus a direct replacment
I use the .90 on a fairly large Tower RC trainer in place of the recommended .60 size (same dimensions and weight) and had to modify landing gear to accommodate the larger prop swing
2 strokes have better weights and muffler configurations for stunt planes... I am NOT saying to can the 4 stroke desire...just giving some perspective
new properly sized 4 strokes are fairly expensive compared to the proper sized 2 stroke engine
Remember, any CL stunt plane will need the engine sized to meet a particular Max propeller diameter
The plane in your photo begs for a modern ball bearing 2 stroke or an old skool iron piston .46 to .51 engine
MY RC trainer=Wingspan: 71" Wing area: 888 sq. in. Length: 53.25" Wing loading: 18-21 oz/sq ft Weight: 7-8lbs. Airfoil: flat-bottom, high-wing REQUIRES: Engine: .45-.60 (2-stroke) or .48-.70 (4-stroke)
Hope some of this info helps

on left is Magnum 1.2, then a Super Tiger .90 then a ASP .061
Note that the ST .90 is nearly same weight and dimensions as the .061 thus a direct replacment
I use the .90 on a fairly large Tower RC trainer in place of the recommended .60 size (same dimensions and weight) and had to modify landing gear to accommodate the larger prop swing
2 strokes have better weights and muffler configurations for stunt planes... I am NOT saying to can the 4 stroke desire...just giving some perspective
new properly sized 4 strokes are fairly expensive compared to the proper sized 2 stroke engine
Remember, any CL stunt plane will need the engine sized to meet a particular Max propeller diameter
The plane in your photo begs for a modern ball bearing 2 stroke or an old skool iron piston .46 to .51 engine
MY RC trainer=Wingspan: 71" Wing area: 888 sq. in. Length: 53.25" Wing loading: 18-21 oz/sq ft Weight: 7-8lbs. Airfoil: flat-bottom, high-wing REQUIRES: Engine: .45-.60 (2-stroke) or .48-.70 (4-stroke)
Hope some of this info helps
fredvon4- Top Poster
Posts : 3963
Join date : 2011-08-26
Age : 67
Location : Lampasas Texas
Re: Need advise choosing a motor.
Mr. Gil is an acquaintance of mine.
I'm not dead set on the 4 stroke. I just like the way they sound. I'll put another 2 stroke engine on it. I've never flown stunt in my life. My Acromaster is the first non 1/2A I've ever flown. No pun intended, but I'll just wing it.
I'm not dead set on the 4 stroke. I just like the way they sound. I'll put another 2 stroke engine on it. I've never flown stunt in my life. My Acromaster is the first non 1/2A I've ever flown. No pun intended, but I'll just wing it.
Cajun66- Silver Member
- Posts : 75
Join date : 2014-01-03
Age : 48
Location : Baton Rouge, Louisiana
Re: Need advise choosing a motor.
Cajun66 wrote:Mr. Gil is an acquaintance of mine.
I'm not dead set on the 4 stroke. I just like the way they sound. I'll put another 2 stroke engine on it. I've never flown stunt in my life. My Acromaster is the first non 1/2A I've ever flown. No pun intended, but I'll just wing it.
Sounds like you are in good company then. If I were you I would latch on to Gil and soak him for knowledge. My guess is he would be more than happy to mentor you.
So what kind of plane is it? Put me out of my misery...
4 strokes do sound very cool. I have one for a future CL project.
Cribbs74- Moderator
Posts : 11880
Join date : 2011-10-24
Age : 49
Location : Tuttle, OK
Re: Need advise choosing a motor.
You are going to really like the way the bigger plane flies....seriously....right engine, right prop, 60 foot lines makes for much more relaxed flying....I love my fast 1/2 stuff and medium .15s on 52, but I truly enjoy big planes that fly straight on 60 lines......
fredvon4- Top Poster
Posts : 3963
Join date : 2011-08-26
Age : 67
Location : Lampasas Texas
Re: Need advise choosing a motor.
Cribbs74 wrote:Cajun66 wrote:Mr. Gil is an acquaintance of mine.
I'm not dead set on the 4 stroke. I just like the way they sound. I'll put another 2 stroke engine on it. I've never flown stunt in my life. My Acromaster is the first non 1/2A I've ever flown. No pun intended, but I'll just wing it.
Sounds like you are in good company then. If I were you I would latch on to Gil and soak him for knowledge. My guess is he would be more than happy to mentor you.
So what kind of plane is it? Put me out of my misery...
4 strokes do sound very cool. I have one for a future CL project.
I've known Gil for a few years. We actually met when he joined our aircooled VW club.
Cajun66- Silver Member
- Posts : 75
Join date : 2014-01-03
Age : 48
Location : Baton Rouge, Louisiana
Re: Need advise choosing a motor.
Actually, a four stroke uses less fuel than a 2 stroke. That will pull your arm quite hard and the need for longer lines would be suggested such as something around 66' eyelet to eyelet and I would also consider .021's. The engine that you would need to fly that plane would be a Saito .72 or possibly larger if weight is an issue. THe UHP venturi setup http://www.ultrahobbyproducts.com/4_Stroke_Conversions.php available through UHP Ultra Hobby Products/ the Moon brothers. The .72 was the staple four stroke for planes that were traditionally using Randy Smith PA .61-.65 engines. However, they're problematic at times. When Randy introduced the PA .75 four strokes were no longer popular and electrics have superceded. Four stroke run far better with a bit more nitro like Powermaster YS 20/20 fuel. The problem is that it's very expensive and having the higher nitro will destroy a top notch stunter that has dope on it. Weight would be the determining factor. Ken
Ken Cook- Top Poster
- Posts : 5105
Join date : 2012-03-27
Location : pennsylvania
Re: Need advise choosing a motor.
The plane was originally a Nobler.
Cajun66- Silver Member
- Posts : 75
Join date : 2014-01-03
Age : 48
Location : Baton Rouge, Louisiana
Re: Need advise choosing a motor.
Thanks! Like I had mentioned the wing looked like a Nobler wing, but the tail confused me. It looks great though.
Let us know what engine you decide to use. The only .60 powered plane I have seen had 1000 sq in. And it was still almost overpowered. Very cool to see though
Ron
Let us know what engine you decide to use. The only .60 powered plane I have seen had 1000 sq in. And it was still almost overpowered. Very cool to see though

Ron
Cribbs74- Moderator
Posts : 11880
Join date : 2011-10-24
Age : 49
Location : Tuttle, OK
Re: Need advise choosing a motor.
Cajun66 wrote:Mr. Gil is an acquaintance of mine.
I'm not dead set on the 4 stroke. I just like the way they sound. I'll put another 2 stroke engine on it. I've never flown stunt in my life. My Acromaster is the first non 1/2A I've ever flown. No pun intended, but I'll just wing it.
That's a very nice plane, congrats!
For what it's worth, my two cents would be to get a engine like it had as the mounts are already drilled, the CG is correct, fuel tank height is set, etc., etc. ....but, only after you have flown stunt for a couple years. I think it would be a shame to wreck such a nice plane as a trainer and you will...first, second or third planes have a fairly short life span.
Re: Need advise choosing a motor.
I get a kick out of how bad they can get their undies in a bunch over there. Phenomenal site though.Cribbs74 wrote:
I don't want to steer you away from this forum, but if you are really serious about going 4 stroke then you might want to visit Stunthangar as they have a board solely dedicated to 4S applications.
Those guys can be a little proud over there so go in with thick skin.
Ron
Jim
JPvelo- Diamond Member
- Posts : 1963
Join date : 2011-12-02
Age : 55
Location : Phoenix
Re: Need advise choosing a motor.
When I was flying competitively
I lived on Stuka Stunt (kinda like I do here) at the time and probably still do, consider it the best forum for control line aerobatics.

Re: Need advise choosing a motor.
Yeah, recently I saw that the moderator had a few warned on time outs with a words-of-advice read only thread post for them to behave themselves.JPvelo wrote:I get a kick out of how bad they can get their undies in a bunch over there. Phenomenal site though. JimCribbs74 wrote:I don't want to steer you away from this forum, but if you are really serious about going 4 stroke then you might want to visit Stunthangar as they have a board solely dedicated to 4S applications. Those guys can be a little proud over there so go in with thick skin. Ron

Other than that, there are also some good posters with a wealth of info. Another forum that is more tempered is the Brotherhood of the Ring, hold out for Ringmaster CL fans, but they are a great group with a wealth of knowledge too. Brotherhood of the Ring

The 049 Collectors Yahoo Group is also another good place to post questions. They are a mature bunch of posters that although in love with 049 technology and history


GallopingGhostler- Top Poster
- Posts : 4071
Join date : 2013-07-13
Age : 69
Location : Clovis, NM, USA
Re: Need advise choosing a motor.
Just dipping my toe in here..
The Saito 82 is one of my fav engines, it's very easy to live with.
Easy starting, powerful, very light weight and very economical like all
well set up normally aspirated 4 strokes should be/don't forget only
one explosion every 2 rotations of the crank. It will also swing a larger
prop than the comparable 2 stroke.Don't forget most 4 strokes have almost
infinitely adjustable mufflers and are MUCH less noisy than 2 strokes.
Not sure if they do a stunt carb though.

The Saito 82 is one of my fav engines, it's very easy to live with.
Easy starting, powerful, very light weight and very economical like all
well set up normally aspirated 4 strokes should be/don't forget only
one explosion every 2 rotations of the crank. It will also swing a larger
prop than the comparable 2 stroke.Don't forget most 4 strokes have almost
infinitely adjustable mufflers and are MUCH less noisy than 2 strokes.
Not sure if they do a stunt carb though.

John Goddard- Diamond Member
- Posts : 2447
Join date : 2011-11-24
Age : 58
Location : Leyton North East London

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