I have a Thunder Tiger Pro 46 that I currently run on 10% nitro.Engine has about 10 litres of 5% and 4 litres of !0% through it.how do u know when its properly broken in?some signs or behavior?

G'day Mate,
After that much fuel through it, it should be run in! does it hold a steady 2 stroke when running? but not too lean, if yes, then it is run in.
What size prop are you using & on what plane?

I'm currently using a 10*7,on my Thunder Tiger Trainer MKII, although i used a 10*6 with the 5%nitro.i also plan to use this same engine on my Ultra Stick as soon as I get my new radio, any suggestions what prop to use to get good vertical power?
ps thanx for the advice

We get pretty good all around performance from our 46 size engines, both Tower Pro & OS with an 11X6 APC prop. My friend uses the same prop on his TT.46Pro with the same good performance results.

I've used a 10.5x4.5 APC on my Something Extra with an OS 46 FX. I was looking for that extra pulling power too, and I'm really happy with the way that prop pulls the plane around.

Ken

Basically with the 40/46 size engines, once the engine runs consistantly and reliably its considered to be broken in. If its done correctly it should only take three to four 10 oz. tanks of fuel. If its still running inconsistantly after that time then either the needle valves aren't adjusted properly or you are running the engine too rich. If the setting is too rich during the break in period, the engine won't develop enough heat to seat it self properly. [8D]

Even after it is broken in I suggest you always run it slightly rich. That TT Pro .46 will last you many years.
I have been running an 11-7 MAS prop on mine with great results. It pulled my 7-1/2 pound Kadet all over with good vertical.(of course it is a trainer)
I just moved mine to an H9 P-51 with a 10-6, 3 blade prop. We will see how that works out soon.

3 blade props in most cases give poor performance compared to 2 blade props. For your H9 P51 I would try a APC 10-7. [8D]