sundowner 50 with OS 1.20
03-15-2012, 03:17 AM
#1
sundowner 50 with OS 1.20
does anyone think it would be inappropriate to build a sundowner 50 with an OS 1.20 CI. they recommend a .40 to .52
if i did this, i would double up the thicknes of firewall and strengthen it with screws/plates.
and thicken the side panels.
if i did this, i would double up the thicknes of firewall and strengthen it with screws/plates.
and thicken the side panels.
[img]webkit-fake-url://9F35BC85-81E8-42C4-8F09-AE8591EB5F28/HAN4725-2.jpg[/img]
03-15-2012, 07:17 AM
#2
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RE: sundowner 50 with OS 1.20
Ground clearance would be an issue, the prop would be too big. That would be a huge powerplant for that model. Weight maybe an issue also, a fellow flyer at our field has one with an OS 46ax with the battery up front and it seems to be a little nose heavy. All that being said....I'd love to see it!!! Make sure you post a video!
03-15-2012, 02:44 PM
#3
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RE: sundowner 50 with OS 1.20
Too much beefing up mods to make it work, which means more weight not to mention the heavier engine on top of that and the little extra gain in horsepower is not worth it because its not going to be faster than just keeping it light with a 50 sized engine. Just my opinion.
03-15-2012, 03:27 PM
#4
RE: sundowner 50 with OS 1.20
i may do it, if i get enough encouragement.
what i would do is use a 4 blade prop, that would decrease the overall prop size down by 2 inches. 2 blade would be 15 x 10, a 4 blade prop would be a 13 by 8 or so. a os .60 can use a 13 x 6 prop, so a 4 blade prop on the 1.20 should work with the clearance.
the OS 1.20 weighs 11 ounces more than the OS .60 engine, with muffler.
the OS .60 puts out 1.7 hp at 16,000 rpm, if you can ever get it to that RPM
the OS 1.20 puts out 3.1 hp at 9000 rpm
that is almost double the amount of HP with 1.20 and weight difference would be 11 ounces on the motor
i would reinforce firewall and fuselage side aft to wing
that should not add more than 2 pounds with engine increase and plywood
instead of 7 pounds
it will be 9 pounds
does it still sound unreasonable?
what i would do is use a 4 blade prop, that would decrease the overall prop size down by 2 inches. 2 blade would be 15 x 10, a 4 blade prop would be a 13 by 8 or so. a os .60 can use a 13 x 6 prop, so a 4 blade prop on the 1.20 should work with the clearance.
the OS 1.20 weighs 11 ounces more than the OS .60 engine, with muffler.
the OS .60 puts out 1.7 hp at 16,000 rpm, if you can ever get it to that RPM
the OS 1.20 puts out 3.1 hp at 9000 rpm
that is almost double the amount of HP with 1.20 and weight difference would be 11 ounces on the motor
i would reinforce firewall and fuselage side aft to wing
that should not add more than 2 pounds with engine increase and plywood
instead of 7 pounds
it will be 9 pounds
does it still sound unreasonable?
03-15-2012, 03:45 PM
#5
RE: sundowner 50 with OS 1.20
one problem
the os 1.20 distance from crankcase back plate to front end of crankshaft is 140 mm
and from firewall to prop hub (114 mm) , with consideration of the cowl, the engine would protrude by 22 mm
thay may not look good
Hmm
i will reconsider
if anyone encourages me,
i may still do it
03-15-2012, 03:46 PM
#6
RE: sundowner 50 with OS 1.20
ORIGINAL: cshahrdar
i may do it, if i get enough encouragement.
what i would do is use a 4 blade prop, that would decrease the overall prop size down by 2 inches. 2 blade would be 15 x 10, a 4 blade prop would be a 13 by 8 or so. a os .60 can use a 13 x 6 prop, so a 4 blade prop on the 1.20 should work with the clearance.
the OS 1.20 weighs 11 ounces more than the OS .60 engine, with muffler.
the OS .60 puts out 1.7 hp at 16,000 rpm, if you can ever get it to that RPM
the OS 1.20 puts out 3.1 hp at 9000 rpm
that is almost double the amount of HP with 1.20 and weight difference would be 11 ounces on the motor
i would reinforce firewall and fuselage side aft to wing
that should not add more than 2 pounds with engine increase and plywood
instead of 7 pounds
it will be 9 pounds
does it still sound unreasonable?
i may do it, if i get enough encouragement.
what i would do is use a 4 blade prop, that would decrease the overall prop size down by 2 inches. 2 blade would be 15 x 10, a 4 blade prop would be a 13 by 8 or so. a os .60 can use a 13 x 6 prop, so a 4 blade prop on the 1.20 should work with the clearance.
the OS 1.20 weighs 11 ounces more than the OS .60 engine, with muffler.
the OS .60 puts out 1.7 hp at 16,000 rpm, if you can ever get it to that RPM
the OS 1.20 puts out 3.1 hp at 9000 rpm
that is almost double the amount of HP with 1.20 and weight difference would be 11 ounces on the motor
i would reinforce firewall and fuselage side aft to wing
that should not add more than 2 pounds with engine increase and plywood
instead of 7 pounds
it will be 9 pounds
does it still sound unreasonable?
03-15-2012, 07:51 PM
#7
RE: sundowner 50 with OS 1.20
i wont do it, but it sure sounded like it could be very fast
any suggestion on a combo i could use to get a very very fast plane using glow?
what do you think can be the fastest:
2 cycle glow engine
4 cycle glow
4 cycle gas
2 cycle gas?
i have a zenoah G38 on a giant red stick, and it is a beauty
i have a evolution 50 cc on an extra 26%, it is solid
and an FG 36 saito gas 4 cycle on a super decathlon
but by far, the fastest i have is the sundowner 36 with the evolution .40 nx nitro engine
any suggestion on a combo i could use to get a very very fast plane using glow?
what do you think can be the fastest:
2 cycle glow engine
4 cycle glow
4 cycle gas
2 cycle gas?
i have a zenoah G38 on a giant red stick, and it is a beauty
i have a evolution 50 cc on an extra 26%, it is solid
and an FG 36 saito gas 4 cycle on a super decathlon
but by far, the fastest i have is the sundowner 36 with the evolution .40 nx nitro engine
03-15-2012, 09:09 PM
#8
RE: sundowner 50 with OS 1.20
If the 1.20 fits the confines of the cowl, that is the first consideration.
Beyond that, you would need the skills, knowledge and machine equipment to lighten that engine and set it up for higher rpm operation.
Otherwise, all you'll have with the stock engine is a plane that is good at vertical drag racing.
I'd ditch the carb and muffler. Run it with a venturi and crankcase pressure tap. That ought to save quite a bit of weight right there.
Open up the crankshaft as far as you dare and do the usual high rpm timing / porting mods.
Pay attention to lightening the piston as much as possible.
I'm just "thinking out loud" with these comments, none of them are "The Gospel" based on actual experience with this combo. I'm speaking from the perspective if I found this plane and engine under the Xmas tree and how I would approach the project.
Beyond that, you would need the skills, knowledge and machine equipment to lighten that engine and set it up for higher rpm operation.
Otherwise, all you'll have with the stock engine is a plane that is good at vertical drag racing.
I'd ditch the carb and muffler. Run it with a venturi and crankcase pressure tap. That ought to save quite a bit of weight right there.
Open up the crankshaft as far as you dare and do the usual high rpm timing / porting mods.
Pay attention to lightening the piston as much as possible.
I'm just "thinking out loud" with these comments, none of them are "The Gospel" based on actual experience with this combo. I'm speaking from the perspective if I found this plane and engine under the Xmas tree and how I would approach the project.
03-22-2012, 12:12 PM
#9
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RE: sundowner 50 with OS 1.20
I have been flying a 4000watts electric version of this plane for a few years the firewall flew out of mine on the first amp draw i did on it 
all that was holding it was a few drops of CA i did fix it and put many flights on that airframe, till the day the wing ripped out in mid air in mid air,I must say it is a fantastic flyer I have another one now a little faster 
here is the vid of the last flight R.I.P. My old friend
http://www.youtube.com/watch?v=TwKz53OtODU
all that was holding it was a few drops of CA i did fix it and put many flights on that airframe, till the day the wing ripped out in mid air in mid air,I must say it is a fantastic flyer I have another one now a little faster here is the vid of the last flight R.I.P. My old friend
http://www.youtube.com/watch?v=TwKz53OtODU
