I know this may be the wrong form to ask this question but me and a friend are still beginners. My friend just got a new SIG Four Star 40 plane. The plane is going together well so far, but he has had to buy lots of extra parts that should have come with the plane and did not. But his major issue is the engine. He is using the old engine of his Avistar which is an OS.(not sure of the size but we know the engine will fit and work in this plane) The engine is fitting the plane great but we are both having some problems mounting the engine. The mount which seems to be plastic is not letting us mount the engine very securely. The mount makes the engine sit sidways or the mount bends, thus giving an unsecure mount. Does anyone have this plane and if so what are your thoughts on this matter? We thought of changing the mount and putting in a metal mount but even the reviews give this plane and the mount a four or five star ratting. My friend is getting very frustrated. This makes a second plane that he has bought and this one seems to be harder than the first one he got. It also makes him a little jellous of me, and the ease of which I seem to be able to build my planes that I have. (I guees building models growing up helped!) But if anyone could help us out please help. Thanks

Aloha,

Cliff
Pearl Harbor HI[8D]

Most kits use a black nylon mount. I am not sure I follow the problem your having. Can you post a pic of the mount and engine together? I just don't understang what you saying.

David

Many mounts that come with planes are of the two peice adjustable type. If not, the mount must fit the engine without having to spread it apart or squeez it together. Which problem do you have?
In some cases you can trim the inside top edges down untill the engine fits.

I don't get what the problem is either. Dozens of people on this site have built the 4* 40, and I've never heard of a problem with the mount.

I'm assuming it's a standard black "plastic" mount, which should be a "40" size mount. You drill holes to match the mounting lugs on the engine; the holes should either be large enough to push a long bolt all the way through, then add a locking nut, or drilled undersized and tapped to fit the bolts you're using.

When you say the engine, "sits sideways", are you talking about a little right thrust? Because most planes have a little right thrust built in at the firewall.

Are you sure you have the mount right side up?

We need more info, pictures would be best.

By the way, not many plane kits, or ARF's, come with 'all the parts needed to finish it'. You usually have to buy stuff. Sometimes just a tank and fuel lines, sometimes wheels too, sometimes you have to buy ALL the hardware.
Dennis-

It also makes him a little jellous of me, and the ease of which I seem to be able to build my planes that I have. (I guees building models growing up helped!)

Aren't you helping him?

The Four Star 40 comes with a 2 piece glass-filled nylon mount. One of the better made ones you can get... If the engine refuses to sit level on THAT mount... you did not put the mount on straight (one beem one height the other a different height... if its crooked... its in how YOU put it on.)
The engine mount off of the Avistar is useable on the Four-Star if you can't figure out how to get the Sig mount on straight.

The 4*40 has a nearly straight thrust line... just a bit of right and a bit of down built into the firewall.

"extra parts that should have come with..." What parts? was it the "kit" or the ARF? The kit doesn't include a fuel tank or wheels or a few other things that would be in the ARF package. The ARF still needs a few items, but not much other than your radio and engine.

Thanks for all of your help so far. No pics available yet but once I get one I will post it. I am helping him build it but it still is not sitting right. The mount is the standard plastic mount. I was not aroung when he drilled the holes for the mount, but things are lining up, just when we go to tighten the motor to the mount it ends up sitting sideways. Give me a chance to post a pic and mybe it will help out some. But thanks for all of your info so far.

Aloha,

Cliff

Here are couple of pictures of the engine mount. Can you describe what your problem is.

The engine in picture is 46FX.

Note that the fuse is shaped for the exhaust.

Hi Cobra,

Ok the problem is the engin is sitting to the left. He has the same mount that you have in pic two. The engine is sitting in correctly when the braces are put over the motor and tightend the engine sits to the left (look at your pic #1) and the mount on the right side is bending to the right. I was able to get the engine remounted and it still looks like it is not sitting correctly, we were able to get the engine started but it quickly started to go off to the left. We have not tried running it since the remounting I did, but it does not look very promising. Not sure if the mounts are supposed to bend that easily, but they are bending very easily. I know this sounds weird and it is very hard for a "newbie" to describe what is happing, just wish I have pics avaiable for you and every one else. I also think part of the problem is the fact that the screws he is using for mounting the motor to the mount are stripped. I think he could use new screws but I find it hard to believe that all of is issue is stripped screws.

Braces?

Do you use braces like most trainers use? The screws go and hold the brace which basicly clamps the engine?

When you said it moved when you start the engine I am assuming thats how you mount the engine.

Put 6-32 bolts through the holes on engine to the engine mount.

I had the same problem with mine, 3 sheets of wing ribs were missing from the kit and all I had to do was contact SIG and they mailed the missing parts ASAP
I'm not sure which parts you are talking about but if it should have been there you should contact SIG and they will mail you the parts free of charge!
unless you are reffering to wheels, fule tank and such which are not included as mentioned before.

Is there a screw going thru each engine mounting hole? It sounds like hes using the same setup that came with my avistar, its a metal slab that sits on top of the mounting holes on the engine and gets tightened(sp?) down. If this is what hes using it can be tricky to get the engine perfectly straght, you have to tighten each side equally.

Sounds to mee like they both need to find someone more familiar with hot the engines should be mounted to look at it in person.

My bet at this point... the holes are not drilled properly in the mount and the engine isn't even firmly bolted to the beams. Maybe they didn't cut out the fuselage's cheek cowl to clear the muffler (and/or the needle valve) and when they thing sttarted to bottom on that...t hey quit tightening the screws?

The last description he gave says to me that the engine shifted when he started it... that means the screws are loose.

I'd like to say thanks to all of you that have helped me and my friend so far. We think that if we mount the engine with out the clamps (like they are mounted on trainers) we can get the engine mounted correctly. So wish us luck and if that does not work we will take it to the local hobby shop and let them take a look at it and get it fixed threw them. Also thanks for the info on contacting SIG about missing parts. That was an idea that neither of us thought off. Once again thanks.


Aloha,

Cliff

Pearl Harbor HI[8D]

Well I guess I should add some since it is my plane. LOL. First Dusty, I was not really jealous of his skill, but how easy the kits that he
had purchased went together. Also, he is helping me. Especially with keeping the thing from being punted. What frustrated me was
everything before the engine. Parts that said to be there (Rods and such) were not and parts that came with it just seemed a little
weak. After talking with other experienced guys at the field and hobby shop, I ended up buying replacement parts in three different
trips. What was frustrating was this kit is almost supernatural in the forums for being a second ARF and although it seems great I
don't think the "KIT" lives up to it.

As for the engine problem, Let me see if I can put it in better words. I had a .40LA and replaced it with a O.S. 46AX in my Avistar.
Too much power plus not fiberglassing the wing = total crash which also = New plane. When it came to mounting the engine I was
not going to be able to mount the old avistar mount without a headache due to there being threads already in the Sig 4 Star Firewall
made for the black (plastic or nylon) separated mounts. First I was going to mount it with the holes only in the engine. After drilling
the holes in the mount I noted that the bolts that I had to use would not fit in the engine holes (they were the ones used to bracket
the engine into the avistar mount). I then drilled two more holes for the bracket and planned to mount it the way it was mounted
in the avistar. Now what happens is as I tighten the bracket, the force exerts out on the bracket and the bracket just bends and the
engine slips from the mount. I plan on now going BACK to the store and getting bolts that fit in the engine and mount it direct.

Hope that gives a better picture. The mount really is not the main thing that frustrates me. Its the poor manual, the ease of build,
and the quality of the kit compared to VMAR and Habbico. VMAR gets torn apart on the fourms but the two kits I have had a chance
to be apart of both were beautiful kits that went together painlessly with everything that it said that would be there WAS!

TNX for all your help up and down this thread!

Tom
Pearl Harbor, HI

I've built many SIG kits and had enjoyed ever minute of both building and flying them. If it's a SIG, it will fly!

My avistar had a dave brown mount built for a .40,but my engine was a .46 so I bought a dave brown mount for a .46 and the holes for the firewall matched right up.As for the holes in the mount,I took the muffler off and turned the engine upside down on the mount.I drilled one hole then I put a screw in it.Before I drilled the second hole I double checked the alignment,then drilled the second,put a screw in,and so on.The mount fit so good there wasn't much room for it to veer off anyway.The best thing was that the mount only costs three bucks.The reason why I flipped the engine over was so the drill wouldn't get in the way or scratch the engine.