Hi,

I know the ideal case is that your engine/bypass is perfectly centered up with your pipe, and that if you ran a laser through it, the engine's shaft would be perfectly lined up with the center and longitudenal (sp?) axis of the pipe. My question is, how "off" is too off? If, for reasons I care not explain, the installation is off-center a tad, how much effect have you guys seen? TIA

Harley?

Shaun, here is what I do to check if the turbine is too much off center: I run the engine for about 3 minutes at full RPM on the first test run at the field. I then get the pipe out. If there is a zone that changes colour towards blue ( inner pipe ) , then the turbine is too much off centre. There is nothing scientific in there but I've sticked to this method for a long time and never got any issue, even with the very flimsy early FEJ pipes ( that I upgraded quickly BTW ).

eyeball it and go fly


my 2c

Sean,
From my experience, if you're off center a bit, it's not a big deal as LONG AS the engine is still running parallel to the pipe. In other words, as long as the engine is blowing straight down the pipe and not towards one side you'll be ok. Depending of course on how far off center your engine is. An engine that is perfectly centered by crooked will damage a pipe quickly. If you're within probably 3/16" of center but running straight down the pipe you'll probably be ok.
Your mileage may vary...

I agree !!!! Go fly that sucker.... Twice !!!!

Danno[sm=tongue_smile.gif]

Shaun,
Here's one way of making sure the alignment is correct. Stick a plug in each end of the bypass tube and another in the pipe exit. Connect them with a threaded rod on center. This will make sure the bypass and pipe are aligned. Then, drill the bypass tube for the straps, and attach the pipe to the bypass tube without disturbing the alignment.
Remove the threaded rod, and install the bypass and pipe into the airframe. Recheck the alignment optically. Install the engine. Eyeball it again from the rear.
This doesn't take very long to accomplish, and will ensure alignment.

Use a hat section between the mount straps to center the engine in the tube (on the bottom). This will also prevent the engine from sagging downward in the event of a hard landing.

I just installed my engine in my Tams F-16 and noticed that it's not quite as centered as I would like it to be. It looks to be alligned a little to the left of center and maybe even a tad low. Based on the pictures is this acceptable or should I tear it out and redrill holes to align it perfectly centered. I'm really worried about trying to redrill these holes close to the original ones. If I do, should I apoxy in the old holes and then redrill? Any help would be greatly appreciated!!!

Thanks,
Chris

It definitely needs to be re-centered. Judging by the first pic looking from the rear, it looks to be off center to the right and low. Plug the old holes with an appropriate size hardwood dowel using medium CA and re-drill to suit once you have cut & sanded the dowels flush.

hey amigo,
keep tabs on the plastic control arms for your stabs. check them periodically as they appear to be pretty close to the engine

Yep....fill, redrill and if neccessary I use washers/shims to get get it where I want it. I dont tweek on it too much.....good ol kentucky windage and go fly man!

True that, listen to Buck on this one. I used plastic control arms on my Tams F-16 when I first started getting into turbines and they melted causing a crash. Even though the control arms themselves were blocked by a balsa sheild the metal rod connected to the metal clevis transferred the heat and melted the control arm. = loss of elevator.

Andy

Thanks everyone for the tips! I re-installed the engine yesterday and got as close to centering it as I possibly could. It seemed even after I centerpunched for holes, drilled starting with the smallest bit and rechecking the cntering it still moved a hair when i tightened it down with the screws.

Buck and Andy,

Thanks for the info on those control arms!!! I guess it never even crossed my mind that they might be too close to the engine and melt. I'll pull them out today and go on the hunt for some quality aluminum arms.

Thanks again!
Chris