I am building a 66" Vector Flight Extra and am having a problem with the muffler on my Siato 100. I did some searches here but did not really find many solutions as to how others have made this work. The problem is that the exhaust port is right on the edge of the fuse, meaning any way I attach the stock muffler will take a lot of cowl trimming. I found a post here that a Slimline Pitts did not work (I do not think it would fit anyway). I also saw some posts on flexible pipe, but at $90 on Horizon's website, that seems excessive. Do I just cut the cowl, change the engine mount to either upright or upside-down, use flex pipe? Thanks in advance for any assistance.

I would sugest the inverted engine and cut the cowl on the bottem of the plane. you always want lots of exit air area and it seems that inverted you can easly direct the air over the engine. the looks do not suffer that much as it is not as easy to see large cut-outs in the bottem.

I have on of these planes but it is the Edge. Inverted os 120 4s.

I put a Saito 91 four stroke on my Vector Flight and used a slimline muffler.

I did have to cut the cowl for the slimline muffler, but not nearly what I would have for the stock muffler. It looks OK.

I called the local hobby shop and they have the flexible pipe from Saito. I am going to take a look at that. I read in a couple other posts that the Slimline Pitts and Saito 100 do not get along all that well.

Let us know what works for you. My 66" Extra from Vectorflight just arrived today and I am considering the Saito 100 for it. I would hate to mess up that beautiful cowl to make room for the exhaust. Did you try the inverted mount for the engine?

ROSS

I have the 66 inch extra and have a TT 91 on it and the stock muffler fits nicely inside the cowl. I have it angled down and to the left side of the plane and it exits out the bottom of the cowl. I am not sure how the saito exhaust pipe angles out of the head. You can turn the engine mount and mount it inverted. The cowl will look much better with the engine mounted this way. This plane is awsome it is the best flying plane I have ever flown and the TT 91 hauls it around nicely.

Rick

I ended up getting the flexible pipe. I cut the cowl to clear the engine, and the hole is not to bad. It is a little longer than I would have liked, but the cowl is long and that extra opening is needed to get it over the head. I thought about the whole inverted thing, but in my time here on RCU, I have seen a lot of posts about people having problems running engines inverted, so I decided against it. Plus I did not want to drill new holes. A Pitts would probably work also, but would most likely require more cutting. I have included pics of how it is so far. You can see in the one from below that the exhaust port is right there and I will most likely have to cut a little more for it to clear the cowl. Thanks for everyone's input and I hope these pics help others building the same combo.

Have you considered the older style curved header pipe? It may give you another option. I'm assuming you have a straight one.

I have attached a pic of my cowl cut-out.

I have an OS 1.2 pumped engine in it with a slimline pitts muffler.

You also might notice that my landing gear is not aluminum.

This is because I found the stock landing gear a little flimsy, a friend of mine crashed his VMAR cap 232 last summer and offered the landing gear to me to use on the Vector Flight 66" extra. Works great!!!

MR G

Here's a couple of pics of what I did with my Edge 540 and a Magnum 1.20

Dean320,

I am running 5 different Saitos inverted and have had only one problem with siphoning which was corrected by rerouting fuel lines. As far as muffler problems. There is not a lot of choices for the saito when space is an issue. The flex pipe doesn't hold up if you need to route it around. I primarily fly warbirds and found a solution that holds up well and sounds awesome. Macspro.com has a 90 degree adapter that I modify by welding an aluminum fitting at the outlet (maintain ID) to fit a 1/2 inch neoprene exhaust header tube. I would suggest using the stock steel nut instead of the aluminum lock nut supplied. You only need 1 inch of clearance and it stays tight. I use the stock muffler on my 180 and it comes loose about every other flight. I have the VF Edge coming and considering the OS 91FX for the extra power.

Jim

I also have the VF Edge 540 in route. Power is planned to be a Saito 120. After looking at the pictures of the side mounted 100 above, I am leaning toward an inverted mount as well. I have a couple of 2 strokes inverted but this will be my first inverted 4 stroke. According to VF, the 120 works well on the 540 in both the advanced IMAC and 3D modes. I plan on doing a complete review as well from the opening of the box, through maiden flight.