RE: 2 Stroke or 4 Stroke? Why?
 

Post deleted. Misunderstanding...

RE: 2 Stroke or 4 Stroke? Why?
 

The 2 stroke vs 4 stroke controversey goes back to the pre-1996 pattern rules. In that era, engine displacement was limited to a .61 CID 2 stroke or a 1.20 CED 4 stroke. When this rule was first written (late 1970's?), 4 strokes were very limited in power output compared with 2 strokes. The rules were intended to level the playing field between the two.

During the 1980's the power output of the 4 strokes grew and pattern changed to Turn-Around style. The 120 4 strokes offered several advantages in Turn Around. First, they could spin a larger prop, which delivered more static thrust and a slower level flight speed. The larger prop also acted as an air brake on down lines, allowing the pilot to achieve consistent speeds and transition more smoothly from manuver exit to manuver entry. The higher power output of the 4 strokes also allowed pilots to fly larger airplanes, which present better to the judges. Because of these advantages, the top pilots went with 120 4 strokes, which established a trend.

Now, with the 2 meter rules and no limits on engine displacement, the advantages offered by 4 strokes is gone. Many pilots are experimenting with piped 2 strokes again. The OS 140 seems to be the most popular, although, I've seen several Webra 1.45's show up at contests.

As was written earlier, pick a combination that works for you and stay with it.


Rob

RE: 2 Stroke or 4 Stroke? Why?
 

[quote]ORIGINAL: Eric.Henderson

I like that pump so much that I actually fitted OS 140 pumps to four of my OS l.60 FX's.

Holly smokers! 4x$100+ OS replacement pumps to 4 of your 1.60FX's! You mean you have more? What does one do with 3 never mine 4plus?
Your not a Lotto winner are you Eric? Hey, you never know!

RE: 2 Stroke or 4 Stroke? Why?
 

I have absolutely no idea how my comments got mixed up with your quote above...spooky.

RE: 2 Stroke or 4 Stroke? Why?
 

Eric,
A little clarification on the OS 160FX installation of the pressure nipple , please. You say to locate the OS pressure nipple in the hole of the left top backplate screw. I assume that is the orientation based on one's view of the engine. ( A photo of the now discontinued OS 160 EFI on the OS website shows top right ). Also , do you drill the crankcase with a bit that is consistent with the o.d. of the backplate screw or a smaller size ( drill number, please ) Inquiring minds wish to know.
Regards,
Frank