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.51 eng. in a .40 size plane

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.51 eng. in a .40 size plane

Old 07-27-2011, 09:18 AM
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Default .51 eng. in a .40 size plane

I am looking at a second/third plane. I'm considering a sig 4 star 40 or a tiger 2 40. I love building kits I get a kick out of it, butI am concerned about my engine choice. I have a old school super tigre .51 that i bought off of my grandpa. I do mean old school. One of the old ones that was made in Italy. He said it's a real screamer. I was just wondering though if this engine is to much for a 40 size plane? Advice and or suggestions?
Old 07-27-2011, 09:28 AM
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Default RE: .51 eng. in a .40 size plane

I don't think it will be an issue. Just don't try any WOT dives.
Old 07-27-2011, 12:20 PM
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Default RE: .51 eng. in a .40 size plane

ORIGINAL: dbarnes6
I have a old school super tigre .51 that i bought off of my grandpa.
sounds to me like you aren't his favorite grandson if you had to pay him for the engine

i'd tell him i want my money back and get yourself an os 46ax

big dan
Old 07-27-2011, 12:42 PM
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Default RE: .51 eng. in a .40 size plane

It'll work just fine, especially if you are building from a kit. Then you can make certain that your glue joints are secure, either one will move right out with that engine, if it's still in good shape.
Old 07-27-2011, 06:16 PM
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Default RE: .51 eng. in a .40 size plane

There's nothing wrong with a G51. Grandpa is right, they are powerhouses and were designed to give .40 size planes a little extra oomph. Super Tigres have a reputation for being a pain when they are new because the break in takes a long time and ST isn't so great about little details like tightening bolts. But if the engine has been flown with you'll likely have no issues.
Old 07-27-2011, 06:18 PM
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Default RE: .51 eng. in a .40 size plane

I'm not sure what you call an "old school" ST but if it's got a round head then it's from the 80's and was a fantastic engine. If it's got the squarish head then it's the later (current) ST. If it's the square head (latest) then it makes no difference whether it was made in Italy or China because the Italians still own the company and oversee production.

It'll be fine in a 40 trainer though so long as the model still balances where it's supposed to. My son fitted a 1.08 into his 40 trainer and it flew beautifully but he shortened the nose by 3" to get the balance correct without adding tail weight. Flying speeds (even in a dive) were kept much the same as with a smaller engine simply by using a finer pitch prop but with a much larger diameter of course.
Old 07-28-2011, 06:45 AM
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Default RE: .51 eng. in a .40 size plane

We've got guys that bolt a Saito 115 to the front end of a SIG Somethin' Extra (a 40 size plane). And, it was (and still is) his 2nd plane. The .51 should pose absolutely NO problems.

SIG makes for a great build. I've done a couple of the 4Star60 flavors (Saito 91s & YS 110). My only suggestion is to use tri-stock to reinforce the firewall to the fuse sides & fuse bottom.

Have fun ...

Oh yea, have you run the ST yet? How long has it been since it was last used? Just thinking about bearings & whether it was stored with after run oil to keep things clean on the inside.
Old 08-01-2011, 05:00 PM
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Default RE: .51 eng. in a .40 size plane

Generally I run ASP 52s in my 40/46 size planes with no problem. For that size engine however the Tiger would be better suited for it. The 4 star is on the smallish size and really doesn't need to have an engine with that much oomph!! Have fun with whatever you pick though![8D]
Old 08-01-2011, 08:42 PM
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Default RE: .51 eng. in a .40 size plane

I put a .72 4-stroke in a .40 size war bird. I think you can easily manage that. In fact I just bought a OS .61 off the classifieds for the H9 piper cub .40. I have to, since I'm at 5600 ft. elevation.

p.s. I'm sure your grandpa loves you very much.

edit: totally forgot we were talking about the Sig 4star. This was my first plane and my second one because I loved it so much after my amateur building mistake. The Sig 4Star is a great plane, does very smooth aerobatics and has cub like slow flying characteristics. It's got a long wing chord and allows for landings about as slow as you want. :P I doubt you'll be able to hurt that plane by going too fast, but it will definitely be good to teach you some throttle control.

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