ceramic_bearings

CONTENTE - GOULÃO

New bearings Specification now available Build by Bocaberings under the F2C Portuguese Team Support

SPECIAL F2C HYBRID CERAMIC BEARINGS

Product

Characteristics

Spec.to order the bearing

Rear Ceramic bearing MR6900(10x22x6)

Ceramic Hybrid bearings using ceramic balls (Si3N4) meet and exceed today’s high tech requirements, offering a long list of characteristics far superior to that of conventional all-steel bearings

Bearing Material

Stainless Steel 440C

Rolling Element Mat.

Ceramic SI3N4

Radial Play

Between C3 and C4

Retainer Material

Polymite Plastic

Hybrid ceramic bearing
MR6900(10x22x6)

Used by the F2C team Control Line Team Contente-Goulão

Front Ceramic bearing MR696-ZZ(6x15x5)

Ceramic Hybrid bearings using ceramic balls (Si3N4) meet and exceed today’s high tech requirements, offering a long list of characteristics far superior to that of conventional all-steel bearings.(Metal shields should be removed)

Rolling Element Mat.	Ceramic SI3N4
Bearing Material	Stainless Steel 440C

Retainer Material	Polymite Plastic
Radial Play	Between C3 and C4

Hybrid ceramic bearing
MR696-ZZ(6x15x5)

Used by the F2C team Control Line Team Contente-Goulão

Answer : Hybrid Ceramic bearings have the normal steel balls replaced by ceramic balls (Si3N4). The ceramic balls are made of a very Hard material - Si3N4-1500-2000 Vick. They are called ceramic because it's easier calling them ceramic then silicon nitride. The ceramic silicon nitride ball is by far, smoother, harder, lighter and stronger than one made off steel.

Why Ceramic Bearings in the actual F2C engines :

- All this theories will not be visible by the chronometer, or during one F2C Team Race if, the precision, and selection of the materials used in the construction of the bearing, will not be considered. This was the reason why the Team " Contente-Goulão " together with Bocabearings developed this high precision bearing. Build with high precision ceramic balls. Also with a different selection process of balls, to guarantee balls of the same size inside each bearing. A very good polished surface in the rings track.

This are some examples of the new characteristics of these new bearings,and the result of 4 year's of tests made by the Team Contente-Goulao building and testing prototypes. And also one year more of developments with Bocabearings.The result are special bearings build by people from Team Racing available to everybody because we have one goal, since the beginning of this project that is,"to allow technology available to all competitors".

After this year European Championship more information will be prepared and presented to you,(Because, at this moment we don’t have the time to prepare that information) to explain how good these bearings really are, as well as the correct assembly process in the engine. Because this bearing have a special precision for Aluminum F2C engines ( with a radial play between C3 and C4 ).

- Stay alert for the next report, about this new bearings, the assembly process in the engine, as well as the maintenance to be considered to increase the bearing life time and performance.

The first law - " Is not only the Ceramic bearings that will make the difference " They will help, and they give us big improvements, but they are not the magical solution .

Until now a lot of people already make some tests with this new technology, but with no good results the first reason is : the balls break. We start to use normal standard ceramic balls at the beginning of 2003, and never break a ball since then ! However, ceramic balls can break but only, if we have different dimension of balls in the same bearing. So in this case we recommend " 0 microns " zero microns of amplitude between balls.

Since the beginning we start hearing other teams tell , "yes we try but they break, and after a few runs they get damage inside the rings", so the answer for us was obviously ,why ??

We discover that is impossible to completely solve this problem, and even in some standard bearings they get similar problem, however we prefer a ceramic with marks inside the ring, then a normal steel bearing.

In the beginning and when we start to use ceramic bearings in the yugov engine, the most important problem was not all the crankcases accept ceramic bearings, the problem is related with the measure of the shaft and the pressing that the crankcase make when is cold !

Get the ceramic bearings, or buy balls for both front and rear bearing, and start to work on the measures of the balls. Or you buy the balls and make the measurements or you request that to the manufacture to do that for you. At the beginning we discover that the first bearings from boca bearings, where very bad in terms of tolerance between the balls, some times more than 7 microns difference. At the moment Boca bearings have solve this problem as long as you order the same bearings or balls that are being supplied to us (Contente-Goulão).

We are using a different material. We have chose Teflon retainer, for many reasons, but the principals are: they don't heat up, they polish the balls when the bearing is running and very important don't glue dirt, that always appear after the engine run's. The retainer is only to keep the balls separated at the same distance nothing else.

The Celeron retainer or plastic are also good (they give the same airspeed) but get dirty after a short run, the Celeron retainer, is very porous and gets very dirty, the same for the plastic, because the surface of contact is much higher and dirt apears on the back of the retainer. Also gets deformed, after the engine gets too hot in a race, increasing the attrition and decrease performance.

Regarding the Teflon retainer we have made our on Teflon retainer, but there is to much work involved. Its necessary to work about 2 or 3 hours after the construction, with a very potent lens to remove wall the small parts, because Teflon is a soft material and very difficult to achieved a good surface finish. But at the end we will get a retainer that will last forever. At the moment Boca Bearing is already with a similar retainer material and can produce that for you... it’s a question of money.

We know that, at the beginning the quality of Boca bearing rings was not good, however boca bearings as improve a lot, and at the moment they have an acceptable Quality.

They need some times to be polish (in both ring tracks), the surface most be analyse, because serial production same times does not allow extreme quality, and we need that.

The problems that appears more often is damage tracks cause by the accumulated dirt, and by the bad quality or different size of the balls. So from time to time or when we watch variations in the regime of the engine, or luck of power, maintenance is necessary ( new polishment or a new ring(s).

We start to do this with “ WIB bearings “ rear bearing and “ yugov “ front bearing.

We get balls and some complete bearings from boca bearings, WIB (the same as lerner engine), and front standard bearing from yugov engine.(c3 from boca ,c4 from WIB).

we chose the balls , make the rings in Teflon, chose the rings, and assemble.

The ideal is no tolerance,” 0 microns “ no more then 1 micron is acceptable, to allow good assembly process in the shaft. This bearings don't like to be tight !!

So if your shaft is tight in the inside ring you must chose another ring, work the ring inside, or you drill the shaft (it's better to beguine with the inside ring). Use diamond paste with a toll specifically manufacture to do that.

We can not give measures, you need to go by attempts some times this process can go for hours and hours of work, because we to achieve a proper tight/adjustment, the bearing must enter in the shaft by hand but with no big effort, its the only thing we cant say. It is not measurable there is no standard measures. Each part is one part, and the measures need to be adapted, to each case. Even the front bearing we have the same situation.

An interesting fact to know, is that only +/- 40% of the rings of standard yugov engine was possible to put in the crankcase without doing nothing, all the rest need to be adjusted.

You need to go by attempts, and to get the normal and standard bearing tolerance, (as the normal bearings), don’t forget that this balls don't increase diameter in a hot condition like the steel balls do. So proper adjustment is necessary.

An important symptom is when the engine is cold has a regular and similar tolerance as the standard steel bearing engine, but when is hot, get more then the standard.

The best, we achieve, in terms of good adjustment is 17 times balance of the crankshaft “pendulum movement “, when we reach the best bearings adjustment. Compared with the normal ( around 6) it’s a big difference. The improvement of this in the airspeed, is around 0.2/0.3 seg faster, and some times its necessary to put more pitch in the prop, because with a normal bearing the engine was not capable to support this adjustement, but with ceramic there is no problem.

Some times its not the air speed, the more visible, the most visible improvement is that the engine runs in the race much better as we say ( goes more happy ).

In the front bearing we have 8 balls, in the rear also 8, we remove 1 comparing with the normal WIB bearing.

Thermal Ceramic bearings have better thermal properties then the steel ball, also The slip of the rolling element during operation is reduced, resulting in less heat being generated. Below you can see temperature performance between Steel and Ceramic Balls.

Ceramic is the future we think that in 2 or 3 years all the F2C engines will use this technology. The Team Contente-Goulão after the support gived to Boca bearings developing this new bearings now, we are sarting to support F2C engine manufactures to produce F2C engines with this technology.