[NSRCA-discussion] YS Questions+more

[Troy A. Newman]

YS QuestionsSound on the 18.1's is very rpm dependant.  I have reduced the diameter a little and it helps on the noise meter. Yet the prop still pulls and brakes about the same.  RPMS need to be about 7800 on these beasts to get the noise. This is where the NMP velocity stack comes in....reduces the top end RPM....and helps distribute more torque down lower so you are not loosing it. 

If you just don't open the carb up all the way you can chop the top RPM down that 200-300 but you loose the benefit of the lowered torque curve.

These little gems are not for everybody and it takes a little getting used to it...it will not have the top end pull if you cob it.....but then again if you know what you are doing you don't need to cob it with a 170DZ anyways. The only combo I know of that has even close power is the OS 200 and suspect it has a little more grunt across the top of things...but it is double the price and who knows about reliability. We know the 160's and 170's are good on the reliability scale. 


As for aileron differential....I find that the more accurate I measure the deflections the better I can dial in a little differential in the radio. Yes more positive in the wing will tend to adjust the rolls to a more speed sensitive differential setting. 


Troy
  ----- Original Message ----- 
  From: Koenig, Tom 
  To: NSRCA Mailing List 
  Sent: Wednesday, March 05, 2008 6:24 PM
  Subject: Re: [NSRCA-discussion] YS Questions+more


  Hi Troy!

  Thanks for the info. I thought you would be toiling away on the next developmental stage of these engines!!

  Hopefully soon, I can find the time to get flying again. I am looking forward to running this little beast. I am still a little concerned in keeping it quiet though.

  Four blade props? I have some of the 18.1 x 12 two bladers but I just cant see how I'll shut the thing up with these paint stirrers??

  Also-one more question to any of you out there in pattern land.

  I have struggled with aileron differential for years. I am just not happy with the rolls. I have tried various design fixes-but about the only one that seems to work is to get the wing back to 0-0 ( which can be achieved by a few ways, design, mix or thumbs) Differential itself does not seem to work if the wing is POA ( well...it works for half the roll !)
  Another black magic fix appears to be to run parallel ailerons-but this only 'sorta' seems to fix it. I like the feel of equal% chord ailerons however.

  I am frustrated with it-I like my planes to roll as if they had a string up its ...........well you know!

  OK-any 'secrets' I need to know??? Very good elevator work fixes it ( hence my 0-0 comment)

  Tom


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