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Old 08-19-2002, 10:21 AM   #91
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that's nice how how much and is that roar legal.
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Old 08-19-2002, 10:47 AM   #92
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Quote:
Originally posted by SmeltzRacing
Here are a few pictures of the Rossi Pixie Black .12.
You have done your work to this, right? If so what was the stock induction duration?
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Old 08-20-2002, 08:07 AM   #93
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Um, what benefit did you find over the stock ROSSI engine with the mods you have made to an engine that I know for a fact you have not yet run? Why have you pollished the crank web? What advantage is there in doing this work? At the moment the standard ROSSI R12 has broken 2 track records in my area, it's relative, the competition runs S3 Nova. What advantage will the eye candy give me? No one will ever see it.
To anyone considering the PIXI, there is potential in this engine, the mixture settings are more critical on this fella than any other engine I have ever run, but the extra effort will give reward. Provided you don't put a screw driver through the backplate and then complain on the net about poor performance, this engine will be worth the extra. If you don't know how to tune a race engine the PIXI is not for you, get a cvx.

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Old 08-20-2002, 08:21 AM   #94
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OZ,
Polishing the crank and web on any engine will increase throttle response and cut down on parasitic drag from the mixture of fuel and air in the crankcase. Think of this: run your finger across a fresh crank... feel the machine marks? Then run it across a polished crank... finger goes smoothly across right? This will decrease the drag that the crank sees while the fuel and air is pressurizing the case and will let it turn easier, thus more revs and better response from the trigger finger. None of that polishing is eye candy. I do the same thing on all my motors. Not to toot my own horn, but I did some work on a OS RG .21 low end motor for a friend on a budget and it ran with the RB S7's and Nova 4port CLB engines this weekend in his Crono RS01 in Oklahoma and still got him 8 minutes per tank of fuel.
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Old 08-20-2002, 08:37 AM   #95
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In fact highly polished surfaces have more boundary layer drag than shark skin, sharks have teeth on their skin to make them slip more easily through water. High speed aircraft have devices on the wing surface to create boundary layer separation. I don't want a more economical engine, I want one that burns more fuel.
Hey they even made a special rough surface for the hull of the U.S. yacht that won that cup back from us.
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Old 08-20-2002, 08:40 AM   #96
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There is windage, turbulance and atomisation to take into consideration.
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Old 08-20-2002, 09:35 AM   #97
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Hey, My golf balls have little bumps on it. If I sand it smooth will it cut through the air faster? Giving me a longer driving distance?


Sorry, Could not resist!
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Old 08-20-2002, 10:22 AM   #98
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The dimples in the golf ball creates little "turbulent" air pockets that stabilizes it in the air.

Whatever you want to say about the polish on the crank, it works whether or not you belive it! Just go to the RB forums and ask Rody why he does it to his "Rody Tuned" engines !
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Old 08-20-2002, 10:42 AM   #99
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Sorry just going to go off topic here.

Buster, if you sand your golf balls smooth then yes you will get a longer driving distance, but you will find it harder to hit the ball straight and get any bite on the greens.

Now I could be wrong about this, but I believe the theory behind a rough surface for a yacht is that it creates tiny bubbles behind the ridge, meaning less friction as the hull is rubbing against air not water. Look at the hull of any Class 1 offshore powerboat or hydroplane and you will see that they have a stepped hull. These steps are positioned where the hull comes into contact with the water when the boat is up on the plane. Again, these steps allow the formation of air pockets behind them thus reducing friction.


Sorry, just felt the need to say this...

Oh, I would like to point out the difference between the above examples and the state of the crank just so it doesn't seem like I am rambling too much.
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Old 08-20-2002, 10:49 AM   #100
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I also thought that the dimples on golf balls were there to produce lift on the ball and be able to make the ball go straight or make the ball fade or tail off (in my case duck hook or slice). A smooth golf ball will go farther but that is only on a perfect hit. Hitting the ball off center will cause the ball to go up in the air but then dive back down into the ground if smooth.

I am very sure that Buster knows what he is talking about considering that his engines are very fast and powerful.
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Old 08-20-2002, 11:30 AM   #101
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Yeah, and I'm sure that Rody Roem of RB doesn't know anything about making engines run better either! LOL!
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Old 08-20-2002, 12:28 PM   #102
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Last edited by Motorman; 03-08-2003 at 09:01 PM.
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Old 08-20-2002, 01:17 PM   #103
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My sentiments exactly, Dennis!! It's like on my Big Block chevy, after porting the intake of the heads, I shot peened the runners for fuel atomization and to prevent puddles. And on the crank throws, I knife edged them and polished them for less parasitic drag. There is a place and use for each type of mod. Too often a copied mod is done incorrectly and makes less power if you don't understand the reasoning and physics behind it!
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Old 08-20-2002, 02:19 PM   #104
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I copied your sleeve work and the crank scallop and it works great, for me....
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Old 08-20-2002, 04:21 PM   #105
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LOL!

First off, I was not saying that polishing those parts did or did not make any improvement. I was simply being funny with the golf ball thing. I have my own beliefs, and I will not sit here on a public forum and bash someone else's beliefs.

On the golf ball theory though, the dimples do allow the ball to go further, it does create a air pocket around the ball, nothing cuts through air faster than air, its as simple as that. Granted there are other reasons for the dimples, but those are not as funny!


And if you have been around the sport for any good amount of time, you would have seen Mr. Rody and myself get into some good debates on the RB forums. And if memory serves me correctly, I have proven myself a few times already. It has been a long time since I have been to the RB site, so I would assume those postings are long gone? What you do not understand, is there are a LOT of home builders that can build just as fast, if not faster motors. Simply working for a RC company means nothing. I know a few 500k a year Mechanical Engineers that build some outstanding motors, do you think they are going to give up that salary to work for a RC motor company?
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