ORIGINAL: Flying freak
Hi
im about to order my first JETT cant wait to get it but im wondering if i should keep an eye on the runnign tempature im scared to damage it (im 15 and thats almsot 1/2 a summers worth of working for one engine) so would it be worth to instal somthign like [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHUH2&P=7]this[/link]??
if so what temp am i looking to stay under
Thank you
Steven
Don't worry too much about it Steven. Don't over complicate things
The engine is very user friendly, you will enjoy it. Sounds like you have good fuel, and are well motivated and willing to take care of the investment... so you will likely have no issues.
Most important thing you can do is install the engine on a test stand for the first 5-6 runs. Follow the run-in instructions. Break in prop for the SJ-50 is an APC 9x6.
Flying prop - stick with a standard APC 9x7 for the first dozen flights or so. Get use to the engine. Then move up to a 9x8. If you have to order just one size, get the 9x8 and just use those.
Make sure the fuel tank in the viper is well padded - foam all around it.
Temp measurement - put that totally out of your head. Not required.
Temp measurement does not really mean much with the majority of fixed wing model aircraft engines. Yes, I know some people seem to think it is important. I do not believe temperature measurement is a useful tool for the average flyer..... and Dub will tell you the same. Unless you have a thermocouple embeded in a fixed location as a reference, a good instrument to read it, and an hour or two of baseline temperature data at every possible mixture and throttle setting as history to compair it to ... you would never get a repeatable reading or any useful information.... and even with that..... it would not likely tell you much about how the engine was running anyway. The temperature of the outter fins, head, etc really mean little to what is going on inside of the engine. If the head or crankcase is obviously hot, the engine would have long since given you another visual/audio indication that it was not running properly... and ignoring that is just plain dumb.
Best engine tools are your ears, your eyes (safety glass and ear protection are highly recommended), your brain, and a decent tachometer - not $800 tach, a good ole $30 one works fine - it is just for reference anyway.
Ed's post on fuel is pretty accurate, as always.
Use the same fuel for break-in as you intend to fly with. Absoulutely no reason to complicate the easiest item in the model aircraft equation.
The castor blend (light blend, usually that 15/3 or 14/4 split) has shown a history of providing some safeguard protection should the ABC engine experience a sudden lean condition (you run out of fuel or suck an air bubble) and there is a temperature spike. It is just a safeguard, and the bearings don't seem to mind it either. So that is what I run..... have for years.... and it is what I recommend to others.
Adding a ton more castor is not of much benfit with this particular engine... might not do much harm, but it will make a hell of a mess.
Bob