World Models Ultimate 40...........
 

is getting close to completion. I've finally got the servos in and tank installed. Engine (OS 46FX) is mounted and need bolts for the Pitts style muffler. The firewall to prop measurement came out a little closer than I wanted but it'll just give me more gap. I have the wing and ailerons ready to hook up but need the rx battery and transmitter charged so I quit for the day. I'm going to use the aileron setup as shown in the instructions even though I've read some complaints about it. So dadburned windy here no one could fly now anyway. Just waiting for some warm quiet weather. BTW,,,,, I retired the first of the month and now have more time to work on this stuff.:D

RE: World Models Ultimate 40...........
 

MAKE SURE you get the right bolts on the muffler!

It's easy to get the wrong ones, which will SEEM to work fine until the engine warms up then they come loose.

So naturally you attempt to tighten them down and end up stripping the whole thing.

I went through this with two of the Pitts mufflers until I realized that the bolts were the wrong size but were almost identical.

The difference is something like .5 on the sizing.

If I recall correctly I went with the Tower Recommended bolts, which turned out to be the wrong ones!

RE: World Models Ultimate 40...........
 

Congrats on the retirement! I had this plane and flew it with an OS .50sx and used the bolts from the stock muffler for the Pitts muffler and had no problems. My blane was balistic using an APC 13x4 Sport prop and I would expect it to fly very well with your .46fx... What prop are you going to use? I too used the single aileron servo set up. If I do it again I would go with twin mini servos, one in each lower wing.

RE: World Models Ultimate 40...........
 

Were the bolts from the .50SX a bit longer?

If I recall correctly ( it's been a while since I put it together ) the stock bolts on the .46 were about 1/4" too short for the Pitts Muffler.

RE: World Models Ultimate 40...........
 

The bolts on the OS .46 FX/AX, .50 SX and .55 AX all go through the back side of the engine block and screw into the muffler (not through the muffler into the engine block) so you have just as much thread into a Pitts muffler as the stock sport muffler.

RE: World Models Ultimate 40...........
 

Thanks.

It's been almost 2 years since I put the plane together and it's well into it's second century of flights... I don't recall the specifics.

RE: World Models Ultimate 40...........
 

Hi,

I bought one of these today and quickly had it put together. Mounted the engine at given distance from firewall to engine propeller front plate. Set at 4.5 inches its about an inch short of the cowel front. Installed an OS 46.

Is the manual wrong or did you cut the cowl down.

Thanks

RE: World Models Ultimate 40...........
 

I don't recall the manual being wrong. Looking at the plane it came out spot on from what I can see... ( it's been a couple of years since I've built one of these as mine are still flying. )

You can just redrill the engine mounting holes on the engine mount and/or get a replacement longer mount.

RE: World Models Ultimate 40...........
 

i think you'll be fine with the ailerons unless you really are into super fine aerobatics. and if you are, then this is way too small a model anyway. i flew with the recommended aileron setup many many times without any issue on my WM Ultimate 30 (pretty much the same size as this one). one thing, the 46 is way too much engine so be gentle. i had a 32sx with a slimline pitts muffler and it was already a rocket. i can't imagine how much more power the 46 will bring to that airframe.

also, get the CG right. i'd recommend that you be a bit more conservative the first flight. my first flight i put the CG too far back and at half throttle my plane was climbing in all orientations, i mean it was climbing inverted AND knife-edge. made for a very interesting first flight. once back on the tarmac i put more weight up front and balanced her at the very front of the recommended CG and she flew wonderfully. would come in nice and flat and slow with the lightest of flares into beautiful landings. you can see my WM Ultimate in my hanger. good luck!