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SIG Somethin Xtra Engine

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SIG Somethin Xtra Engine

Old 07-30-2015, 06:00 PM
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acdii
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I was going to put an OS 70 on one, until I went to mount it and found the mounts it comes with are too tight, and the mounts that fit the 70 correctly would require redoing all the T-nuts, but puts them where the tank floor is. More work that its worth, so looking to find the right size Saito that will fit without modifying the mounts. All I have right now are 100 and 125 Saitos.
Old 08-01-2015, 08:59 AM
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JollyPopper
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Without knowing what mount you refer to, it is difficult to say what engine would fit it. I have a Magnum .46 two stroke in mine and it will go vertical. Not unlimited vertical, but vertical with limits. The SSE is not a big airplane. I had a Tower Hobbies muffler on it that came on a Tower .46 and the engine screamed, sounded like it was going to blow up. This was that big, ugly tuned pipe kind of muffler. It must have been turning a fantastic amount of RPMs, so I put the original muffler back on it. It still goes vertical although it dropped a bunch of RPM..

I have an OS .56 four strike in a Four Star,Forty which, if I remember correctly, replaced an OS ,46 FX, which leads me to believe that the OS .56 four strike may have the same mounting pattern as the OS .46 two stroke FX.
Old 08-01-2015, 03:35 PM
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Gray Beard
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Acdii, try using the GP adjustable mount.
Old 08-01-2015, 04:14 PM
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DGrant
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You might try using a Dremel or rotary tool to bevel the beams enough for the mounting lugs to seat.... provided theres enough meat left on the beams. It usually only takes grinding a bit off the top inside edge of the beams, enough so the engine sits flat on the beam. Then simply drill and tap the mount for a 4/40 screw... and mount accordingly. That's pretty much how I'd do it...

There's nothing wrong with modifying the mounts within reason. If we have the talent/skills to fly the plane.. a bit of adjusting to get the engine in a good position is a piece of cake.

Good luck with it.
Old 08-02-2015, 05:41 AM
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acdii
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I considered doing just that, DGrant. The book says to have the back plate 4 1/4" from the FW, and the OS sticks out at least an inch further, so dont know how that will affect the plane. I will have to make some notches in the side cheeks for the needle which is why I am hesitating putting this engine on. I should be able to stand it on its tail with the 70 and have it just hang there, but not sure if I want to hack up the nose just yet to do it. That and I dont have any green dope to fuel proof it.

Does extending the nose out affect CG in any way? So far I have not had a plane where I couldnt get the engine to line up with the plans, but this one appears that there is no way for the 70 to sit at 4 1/14 without modifying the firewall.
Old 08-03-2015, 08:49 AM
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acdii
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Well after fiddling with it, I got it mounted, and its only 1/2" further out than called for. Carb sits above the tank, just like in my LT-40, which runs fine, so not concerned about fuel flow. I got it to fit by beveling the mounts to accommodate the crankcase, and it dropped right in. What I thought would be an issue, turned out to be a non-issue, the cable for the throttle turned out to be in a perfect position, right above the tank. I mixed up my own green dope, though I only have Cub Yellow, it isnt as light green as I would like, looks more like Zinc Chromate, but its fuel proofed now where I had to notch out for the needle.
Old 08-03-2015, 02:20 PM
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daveopam
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.45 - .55 two stroke is the easiest on this plane. I have had a Saito .82 on one so I know your 1.00 will fit. It's just a pain hooking up the throttle there is not a lot of room. I ended up having the carb turned so the throttle arm was toward the left side of the plane. I was able to carve out enough of the cheek to clear the arm. Still really tight so I used a solid 2/56 rod and attached it to the carb before I installed it in the plane. then fed the rod through the firewall as I moved the mount back to the fire wall.
The other thing with the big four beater is prop clearance. I did have to pull the gear and bend it taller and bend the axle tabs so it would clear a 14" prop.

David
Old 09-05-2015, 03:31 PM
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acdii
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The 70 is perfect for this plane. Flies great. Have a slight throttle issue, but I may have it resolved with a new needle assembly. Took a few flights to get the hang of landing without it bouncing back in the air, but man can it fly slow.

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