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

Ed Smith

Run the engine according to Jetts instruction with the appropriate propellor and fuel, it will not overheat. You really should have a tachometer to set the RPM.

Ed S

Flying freak

I have a tach i will run be running my standered fuel through this engine (15% nitro 18% oil)

Flyboy Dave

My Feedback: (21)

....make sure the fuel has plenty of castor in it.

Flying freak

50% castor 50% syth.

total of 9% castor, is that enough??

Flyboy Dave

My Feedback: (21)

....yes, that's great. Jett recommends PowerMaster fuel which is 1/3 castor, 2/3 synthetic.

50-50 is even better. The more castor, the cooler the engine will run.

FBD.

wylieruneyjr

With a big investment like a Jett engine it might not hurt to add a little pure castor oil , like two or three ozs. per gallon. If your engine is not smoking at full throttle, you should see aleast a faint smoke trail. Its important to understand that once the plane starts flying the propeller will spin alot faster in the air at speed than it does on the ground. Some say the prop unloads in the air, and jett engines unload alot, needing more fuel than it does on the ground. Sometimes running richer on the ground , plane not turning as fast on ground, is faster in the air, cause when the engine, prop unload they need more fuel, the more you got the faster it will go. So try your fuel, run rich, and look for a slight smoke trail. And once you do a full speed dive LOOKOUT for flutter, rapid back and forth movements of control surfaces, sounds like a buzzing noise, very bad, will rip your plane apart in a mil-a-second. And Jett engines can and do provide enough speed to cause this on some planes. What size Jett you gonna buy? I really like the sport 40, don,t over look this beast, its so fast, and bigger is not always needed. As far as temp, can,t tell you, never did a temp reading, however if the glow plug gets loose its to hot richen it up, if the engine head loosens up its to hot richen it up. and check this often til you learn this engine. Check muffler bolts, carb bolts as well, if anything is getting loose its too hot. Also glow plugs should last, if you are replacing plus after one to five flights you are too hot! Hope this helps.

Cyclic_ Hardover

Jett's are very durable engines. "You get what you pay for." I have three of these engines. They are the best and so is customer service.

combatpigg

My Feedback: (3)

I don't know what a IR temp probe costs, but some flyers use them. I think most engines should read about 300-350 degrees measured at the head. According to an old FOX ad, castor breaks down at 400.

Ed Smith

The Castor oil syndrome is a myth. If you want to gum up the insides of your engine and subsequently clog the bearings then use Castor oil. As recommended Powermaster 15% is suitable without the addition of any extra oil. Break in the engine with the fuel you intend to use for flying. Apply some logic. why would anybody break in an engine with one fuel then use a different fuel for flying. Doing that starts the whole break-in process over again. Different fuel, different rpm, different heat range.

Read some of the European engine sites. They laugh at the use of Castor.

Ed S

Flying freak

The engine is going to be a jett 50 on a viper 500 (a have a club member i need to beat on low fast passes)

When i check if things are comign loose do you do this right after landing when the engine is still warm? im probably only going to be getting 4 minute flight times

can someone please recomend some props for a jett 50 fire tuned for high end speed, i ahve to order all my props in packs of 6 and it takes a week to get to me so id like to pre order them

evan-RCU

Engine temp should be 220degF. Colder than 200 is too rich, hotter than 240 is too lean. Use a IR gun on the head or the back of the cylinder for the hottest spot. OR you can use the old fashion spit test. A drop on the head, if it sits there and bubbles it's good, if it just sits and does nothing you're rich, if it sizzles or jumps off you're lean.

bob27s

My Feedback: (19)

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