I posted this earlier in the ARF or RTF forum and decide it might be more suitable for this forum. I'm in the process of assembling a Tiger Stick 40 to fly as my 2nd plane. I'm installing an OS 46 FXi on it an I'm wondering what I should use for the optimum right and down thrust angles. The manual suggests up to 2 degrees right angle but makes no mention of down angle thrust. Opinions of the guys at the club are all over the map on this one so some good advise would be appreciated.

Typical setup would be 0,0,0 to each other and plus 2 to the datum line. 2 degrees is a good place to start on right thrust, but depending on what you prefer anything from 0 to 3 would be acceptable. Motor thrust angles, both down and right depend alot on what your going to use the plane for and personal flying style, thats why your getting so many different answers.

The info you gave leads me to question my own build in progress. I'm building a Sr Telemaster,w/Fuji BT50SB engine its for towing.Well the down/right angles change from the stock position given on the plans?The engine is bigger & weights more than required. Thank You Phil

Yes, the engine certainly weighs more than the design assumes. 4.9 lbs vesus what for a 60 two-cycle? about 1.5 lbs?

What you're really going to need is a shorter nose. 78oz vs 24oz.............

And the structure is less than robust. Adding weight to balance is going to create a "dumbell with a balsa bar."

is this a serious post - "a Fuji in a Telemaster?"
me thinks it is in jest.
I once did a review with one of these boatanchors
at 2800rpm -my heavy all steel test stand would walk across the concrete -driven by the vibration at that speed.

Not sure you should have any down thrust on an aerobatic airplane with a symetrical airfoil. Remember it will be up thrust when you are upside down. Same with right thrust. Now if you are using it as a trainer, then 1 to 2 degrees down thrust and two degrees right thrust might be helpful but not required on that model.

all of this angling of the engine is just to compensate flight which has a significant angle of attack
many of the old designs struggled around and wer a handfull on landing and take off and in a vertical line (well- a steep climb) were slipping and skidding and the props added a fair bit of unwanted forces.
really light aerobatic stuff which accelerates very easily don'tneed any of this angle business actually inmost cases you don't want any of it Now if you are building a Islander with the engine mounted on a pylon (the vertical fin) - you are going to want some angles.
some pattern guys believed (incorrectly) that one could design a plane which flew hands off thry any maneuver and held any line -
fat chance
the closer the model got to THIS condition -the more unstable it became

The Thunder Tiger Stik 40 is an aerobatic model. As such I'm expecting that you'll be putting the CG at a suitably aerobatic location. That means the CG will be located fairly far back and close to the neutral point. With that in mind you should need little to no downthrust and at most only a degree or two of right thrust to sort of compensate for the power up front. At most I would suggest 1 degree of downthrust but really it should be zero.

Set the CG via a series of dive tests such that it has little or no tendency to pull up and not a hint of tendency to tuck to a steeper angle. Then if you find that the model is nosing up strongly when it speeds up due to diving or adding power only then shift it to one or two degrees of downthrust. But it's likely you won't need to add any at all.

Downthrust is a bandaid added to compensate for a strong positive pitch stability. Trainers run with a high degree of positive pitch stability so they need lots of downthrust. Pattern models with their razor edge design and trim need no down or right thrust. The rest are somewhere in between depending on how close they are to one extreme or the other. Your Tiger is closer to the pattern model.

I have found that that leads to a bit of left rudder to correct for the right thrust. Which still leaves you a model that will turn to the left when you apply throttle. Most pattern people will tell you to put both at 0-0. You need to learn to correct for P-Factor. It does nothing for a model flying level at a constant speed.

me thinks?......cant even talk right!!!!