[NSRCA-discussion] OS 91FX or 120 AX for Focus sport

[Jay Marshall]

I fly both engines. If you are flying Sportsman, then 1.20 may be an
over-kill. I used the 1.20 on a Venus so you might compare the Venus and
Focus Sport side-by-side. If they are about the same, then use the 1.20. If
the Focus is smaller and lighter, then use the .91.

 

Jay Marshall 

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Ken Velez
Sent: Thursday, June 26, 2008 1:44 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] OS 91FX or 120 AX for Focus sport

 

1.20 AX is a better choise I think just because it easyer to operate and
besides it has more power.

 

Ken

----- Original Message ----- 

From: Shoval Aviv-BAS036 <mailto:aviv at motorola.com>  

To: nsrca-discussion at lists.nsrca.org 

Sent: Thursday, June 26, 2008 1:24 PM

Subject: [NSRCA-discussion] OS 91FX or 120 AX for Focus sport

 

Hi All,

I'm fairly new to pattern flying. I'm considering to buy the Focus sport and
want to "keep it simple" with the engine. I know the Focus was design for YS
110 but for cost/ simplicity reasons i am considering the OS 91 FX or the OS
120 AX. In the OS web site they claim that the 120AX is 20% more power but
when I compare efficiency it looks like the 91FX wins. Its 6% more efficient
in power to Wight and 16% more in power to displacement. Am I missing
something? Practical RPM misleading numbers? What would be your
recommendation?

 


 

120AX

91FX


Displacement (Cu in)

1.2

0.91


Weight (gr)

650

550


Output (BHP at RPM)

3.1 at 9000

2.8 at 15,000


Cost

250

200


 

 

 


output/ weight

0.004769

0.005090909


Output/ displacement

2.583333

3.076923077

 

 

Best Regards,

Aviv

 


  _____  


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