RO-JETT ENGINES

51/61/65 BSE SE/RE

RO-Jett Engines is proud of the bar stock engine that is sure to reset the standard for size and power. With all new design inside and out this is truly a STUNT MOTOR. These motors were designed for stunt and only stunt. Some of my customers relate to these motors as Jewelry.

Break In:

Please take the time and care to break in your RO-Jett engine properly to increase the life span and power available to you. Give you engine a good 1 ½ to 2 hours running on a test stand. Use a prop that is smaller than you will be flying with so the engine will run cool and easy while breaking in. Do not confuse cool with very rich. If the engine does not come up to operating temperature then it is doing damage, not breaking in. You want the engine to get to operating temperature with a light load (small prop) and lean enough to reach this temperature. If the needle is set very rich it will not reach this temperature and the rod and piston will be trying to force a piston into a tight sleeve that has not expanded to its appropriate size. I use an 10-6 APC or Master Airscrew plastic prop for this. Start with the needle 3 full turns out to start the engine and needle in from there after you get your RO-Jett started. I set the needle for a setting that is just short of a 2 cycle. When you reach this point the engine will not be sure it wants to run in the 4 or2 cycle mode. It will oscillate between the 2 cycles but mostly stay in the 4 cycle. This is going to be a higher RPM than you are used to, so be prepared. It may even be several thousand more. Do not be alarmed. Higher RPM is not going to damage your motor if the needle is set rich. I run the engine here for a few tanks (8 oz.); I try to run it at least 8 to 10 tanks. Let the engine cool between runs.

This is the least we suggest to break in your motor. Do more to assure the motor is broken in by making the run time 1½to 2 hours total. Either way give your motor slightly rich first runs in the air in your plane. Always start from the rich side and needle in each flight to make sure you do not damage the engine. I see way to many engines burned up early in their life from wanting to have a NATS winning run on the first flight. Resist this tendency and start from the rich side and slowly find the right setting for your prop, fuel and speed. Do not put your biggest prop that you have for your first flights either.

Flying:

I liked the Bolly and Eather 3 blade props. Off the shelf there are several APC props that work. Each airplane has its likes and dislikes. The Range of RPM that your RO-Jett 51/61/65 seems to be happy is 9800 to 10,800, on a pipe. This will be different for each prop and weather

conditions you fly in. For the muffled engines I found the engine is happy flying any where from 9500 to 10,500. Chose your flying prop for your flying style. Even if you run in a 2 cycle the engine will still break, it will just be a soft break. If a 4-2-4 is what you want you will want to prop for it and set your needle for a slightly rich setting and the engine will break into a 2 cycle, again it will be soft.

Plug:

I have found most hot plugs run fine. Try different brands and types to get the run you want. I like the Thunderbolt brand from Global (Hobby People, mail order), Standard or R/C version. The 4 stroke plugs seem to work well. Fox is OK, it is just not the best. Hanger 9 plugs work fine, and of course the old reliable K&B is good. The name of the game is experiment and find the right one for you.

Head and Clearances:

Your RO-Jett engine is supplied with a 2 piece button head design. This system consists of a clamp and button. We set the head at the lowest possible clearance you will ever want. I run these engines at sea level and in hot weather. You should never need to lower the head. In some cases you may want to raise the head for your conditions. I put a couple of shims with you engine and you can put them in to help if you have the need. These are .002 and .004 shims and 1 or 2 are enough. If you think you need more I like to change the button in the head to one with more squish band height. This keeps the combustion camber and the plug in the same place. When you put lots of shims, 010-.030, it moves everything up. The button head system means all you need is another button to do the job. A button sells for 12.50, as opposed to buying a complete head for 30.00. We stock buttons for all our engines with .005 intervals. RO-Jett engines are designed to not need the head way up to get a good stunt run. In other engines this is used to keep the engine from running away. This causes several other problems of which number one is power is less and the engine is not combusting cleanly causing you to waist fuel. This same tactic is one reason why the engine needs tuning every other day to get it right (tuned pipe). With the head way up people are opening up the venturi to get the power back thus causing the engine to need tuning from day to day. If it sounds like I have been through it I HAVE! This is not as much of a problem with muffler equipped engines, but it is a part of the equation.

Needle and Needle Valve Assy:

Your RO-Jett is supplied with a needle that will almost never break from normal use. Screw the needle in the spay bar first then slide the jam not onto the spray bar and tighten. Do not over tighten the nut to get your needle to not turn on its own while flying. This is a compression nut and only needs for the needle valve to have some drag to keep it from turning while engine is running.

Venturi:

Your venturi comes with a #12 drill size hole (189). If you want to try a larger size just drill out. Venturi’s are 15.00, so if you make a mistake call us and get another one. Remember a little goes a long way. Try drilling no more than .005 to .010 at a time. If you like, call and buy 2 or 3 extras from us and we will have them the right size for you.

Maintenance and Repair:

Try to keep your engine clean. Use an air filter at all times. The Bruline filter is very good. It has a coarse and fine to match your needs. If you can not find one we can sell you one. If you want a free one then get your wife or girl friend to not throw away her used panty hose. Cut a 1" square piece and use an O-ring to keep on your venturi. If you can not find an O-ring (Home Depot, rubber plumbing o-rings) then use wire or string. Point is USE one. As the old saying goes pay me now or pay me later!

If your engines needs repair, IE, bearings and such send it in and we will get it right back to you!

Crank and crank stud:

We have made the crank so it will fit a TRU Turn spinner back plate without needing an adapter. The ¼-28 threaded stud servers 2 purposes. If you crash the stud gets bent and it is 2.00 and not the cost of a new crank. If you need to use a prop shaft extension to get the spinner further out all you need is a longer threaded rod to get it to match. This means you do not have to have a special spinner adapter and drill a huge hole in your props. This is the lightest way to extend you shaft! We also make an integral shaft extension. Simply remove your old prop drive from the engine and put on the extended one. That simple!

Fuel:

I use and have Power Master mix the RO-JETT blend. It is 10% nitro, 22% oil with 5% being castor. I use this year round and have never found that I need to change. If you are a big castor fan then use the Power Master GMA blend of fuel which has 22% oil with ½ syn. and ½ castor. I do not recommend changing Nitro content in different weather. When you break in your engine it is best to stay with the nitro percentage you break it in on. This is not to say you can not change, but, it is not good to flip flop back and forth.

Email us if you need help or have a question. Check the web site for the videos, coming soon from RO-Jett Videos, how to run, break in, and fly your engine, also the RO-Jett and Jett Story.

RO-Jett Engines

Richard Oliver

12530 Millscott Dr.

Houston, TX 77070

www.rojett.com

Richard@rojett.com