[NSRCA-discussion] APC 18.1 x 10W props

[vicenterc at comcast.net]

Mike,

Do you change props when you are in very windy conditions?

Thanks,

Vicente "Vince" Bortone

-------------- Original message -------------- 
From: "Dr. Mike Harrison" <drmikedds at sbcglobal.net> 

Peter,
I understand your concerns about the YS abuse.  It seems the OS 1.4 "doesn't care", it just goes a slower rpm.  I have spent a few years learning mostly by luck how to make the OS work.  I am quite pleased with it at this point.  I have more than enough power and minimal maintainence.
Mike
----- Original Message ----- 
From: Peter Pennisi 
To: 'NSRCA Mailing List' 
Sent: Wednesday, November 15, 2006 7:48 AM
Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props


Hi Mike,
 
Thanks for the reply.
 
Normally I would just fly the prop but I would like to try it at a comp on the weekend. I just wanted to see if the engine would pull it because it is a big propeller compared to what I normally use. 
 
I also mix my own fuel which has a mix of LV and HV oils. Unfortunately I sacrifice some power compared to running all LV oil (similar to CP 30% heli) I also run only 25% nitro to keep the fuel bills down. I wanted to determine whether I had to change my fuel to overcome the greater load. We have very hot and humid conditions where I live. A overloaded YS in our conditions won?t last too long. From my experience a DZ turning under 8100 will struggle to produce good power in the air.
 
I will mix up a batch of 30% fuel and give it a try. I am really looking forward to trying it as most people think it is the best prop they have used.
 
Regards,
 
Peter 
 
 
 



From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Dr. Mike Harrison
Sent: Wednesday, 15 November 2006 23:31 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props
 
Peter,
Hi,
I am Mike Harrison, I worked with APC to develop these props.  Let me tell you the goal of the prop design.  It is to fly at a moderate to slow constant speed under the noise limit but with good pulling performance.  Therefore, regarding the rpm, the 8000 is about ideal for that prop, turn it much more and you will be above the noise limit.  
 
I find it interesting that you determine whether a prop is adequate by first tacking it.  I would think you would fly it first to see if it was adequate.  I would encourage you to do that first.  The OS 140 turns it about the same and it flies very well. 
 
The whole purpose was to develop a prop that would fly at a deliberate pace at about 150 meters to compete with the electrics.  
 
There is also an 18.5x9.5 which I fly and it turns about 7500 rpm.  I like it better than the 18.1x10.  I am working on a 19x9 at the moment.
 
Good luck
Mike
From: Peter Pennisi 
To: 'NSRCA Mailing List' 
Sent: Tuesday, November 14, 2006 5:48 PM
Subject: [NSRCA-discussion] APC 18.1 x 10W props
 
 
I recently purchased some 18.1 x 10W APC props for my DZ160. Apparently there appears to be another version 18.1 x 10.1.
 
Could someone please tell me the difference between both?
 
I tried a quick ground run on this prop (stock) this morning but could barely get 8000 RPM from the engine. I will take advice from a member on this list and lop 1/4inch of each blade. What RPM readings are people getting who are using either of these props on a YS DZ160 engine?
 
 
Regards,
 
Peter 



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