[NSRCA-discussion] YS Questions

Wed Mar 5 15:25:24 AKST 2008

YS QuestionsHey Tom what's up brother? 

The velocity stack that NMP is producing I did the testing on it. I prefer it. It makes the engine smoother and lowers the torque curve. Basically you get more power down low on the curve that wide open and you don't need to go higher as a result. It gives it more grunt out of the hole. Going into maneuvers like the rolling S we had last year...you can enter with low throttle setting and grunt the model up the hill with the power. This makes the figure smaller and look better. The more speed you have the bigger the figure has to be. 

The velocity stack, also helps to reduce the intake noise from the engine and makes it run smoother and sound smoother. It reduces the top end power about the same as the air cleaner but does a better job of quieting the engine. The opening on the NMP stack is about 8.5 to 9mm. I played with all kinds of different ones. Anything over 9-9.5mm didn't do much at all...The 8mm diameter was a little too restrictive and started cutting bigger gobs of power off the engine almost restricting it too much.

By the way the original 140DZ used to ship with a restrictor for the carb. It improved fuel consumption and did the same thing...the magic I found in doing my testing is the diameter on that original restrictor was 8-8.5mm So the NMP is slightly less restrictive and it helps get a  better flow. Nitro engines work better when the flow is smooth. No sharp edges. Gasoline engines like sharp corners and turbulent flow. This helps to atomize things better and makes for better combustion. The Gasoline atoms are heavier and come out of suspension in the air easier.....Alky based engines like our YS engines like smooth cleaner flow. The Velocity stack idea does just that helps develop flow and make things more efficient. It robs a little power off the top but adds a bunch to the low end torque of the engine.

As for the next thing Yamada is working on. Right now I CAN"T talk about anything that we are running and testing right now. There are some new ideas and new things coming. This is something that will trickle out over the next few months but its not ready for prime time in any way, shape, or form right now. The production of this new setup is far off. Maybe a couple years or more if ever.  As always Yamada is improving and living up to the reputation he has as the king of the F3A market.  If those things including the testing we are doing now ever see the light of public knowledge will depend on how they work. Many of the newer things don't make it out right away. Look how long it took for the 1.60 to hit the market. Original testing back in the 1997-1998 with the 160FZ that a few top pilots had. Then in about 2005 the 160DZ came to market. Sometimes it takes years of testing and development to produce such an idea to market. 

Right now the 170DZ is the king and does everything bigger and better in my opinion than the other options. When the cat gets out of the bag on the new stuff I'll be able to tell you how it works. Right now its got a few bumps in the road but they will get solved and it should be something really cool for the guys that want to go this way.

I will say this. My current front line setup is a 170DZ, NMP velocity stack installed in the Euphoria bipe. Nothing better for that application at the moment. With the 4 blade prop turning about 8000rpm it meets noise limits and has tons of power for the Euphoria.

Troy Newman
Team YS

  ----- Original Message ----- 
  From: Koenig, Tom 
  To: NSRCA 
  Sent: Wednesday, March 05, 2008 3:48 PM
  Subject: [NSRCA-discussion] YS Questions

  Hi again all, 

  It has been a bit quiet lately! 

  I have a couple of questions if I may. Since I have not actually run my 170 yet, I was wondering if any of you have used the NMP velocity stack. Is there any point to it?? Running an air filter on the 160 had cost me power at the expensive of longevity-but the velocity stack kinda makes sense?

  On another note, we all know how Yamada San operates regarding development and 'teasing' us with the next 'maybe' toy. So........any of you 'endorsers' have the low down on which direction YS is heading with the new engine development?? I would assume it would be a complete new crankcase for a larger capacity engine than the 170. I am trying to think of 'what' engineering differences/improvements could be made???

  Can the likes of Troy N or others even let the cat out of the Bag?? Are you sworn to secrecy this time around?? 

  Thanks guys-I hope your winter isn't too bad. Please send some rain to our parched little corner of the earth!! 

  Tom 

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