I am considering a venus .40 and I want it to be very powerful in vertical. I am considering and prefer 4 stroke:

OS70
YS63
Saito72

I have searched on venus and read that the OS70 does climb out vertically but not with authority. I want to pull up vertically and with authority power up to the clouds. Nothing I have read comments on the YS63 and the Saito72 seems to get a bit better performance than the OS70. Does anyone have any suggestions short of an OS91 4 stroke. Although From what I am reading sounds like a stroker OS91 would not be too heavy for the venus and I bet this motor would rocket the venus. I just don't really want to go that big. Anyone use a stroker OS91? Any comments with vertical on your 70 class strokers?

The YS 63 is the most powerfull of the bunch, (a guy posted RPM's a while back proving so.), and it would have the best throttling, easy tank location, etc. A 91 would be too big, and would add weight which would mess with performance.

Ditto the YS 63...


Thinking about getting one w/ that motor in it.

Really though why would a stroker os91 be too big? It weighs only 4oz more than the Os70 and if adjustments are made with the weight and CG in mind, seems to me it would be awesome. My original thoughts for not really wanting to go 91 size was for fuel conumption and concerns of the motor torque inducing twist on power increases. The more I think about this the more excited I get. I can just add throttle to aileron mixing and counteract the torque. Set up my helicopter idle1-2-3 switches for low rate and mixing on idle 1, high rate with mixing on idle 2 and high rate no mixing on idle 3. Essentially creating a precision monster capable of climbing torque rolls. Seems possible.

I agree the YS63 is the best motor of the ones I posted. I just don't see the YS63 having the vertical authority.

Robert, are you flying a YS63 in a venus? If so what is the vertical performance?

I had a Venus with a OS 50sx in it. The plane had unlimitted verticle with that engine. A OS 91 2 stroke is waaay to much power for the Venus.

Awat, what is your definition of "unlimited vertical?" I am looking for the kind of power where you could drop to idle rpm's, fly straight up until stall then nail the throttle and watch it climb out with force and aggression. By this I mean the same kind of authority you might see watching a regular takeoff with a quick stunt type plane where it is at idle and stopped on the runway and then full throttle added (if you know what I mean). Does the 50sx give that kind of power? If so I may go with the smaller engines. I am just fishing for ideas and want a good representation of which engine gives what kind of performance in vertical flight. All I have read so far is that the OS70 and 46 size engines give vertical but slow and gradual. This to some could be considered "unlimited vertical." Although this is not what I want.

Also it is an OS91 four stroke I am considering. I agree 91 two stroke is a bit much.

I have a Venus with a bunch of flights on it. I have an OS 46 FX with a performance specialties muffler. This airplane will disappear going straight up! We're talking serious unlimited vertical performance! It's light too. I would highly recommend this combo!

Chris

That sounds great Chris. I really want a 4 stroke though. My problem is that I don't think the OS70 or the YS63 have quite the power that I crave. Every post I have read so far regarding these engines in the venus just is not selling me on them. I was hoping someone would have some insight from experience on the OS91 four stroke with the venus or similar size models. Thanks for the heads up on the 46 though. My buddy has a Saito 72 in one of his venus' and he wants to get another with a 46.

This should sell you. I have a 350 V8 in mine. Boy! talk about unlimited vertical!!!!!!!!!!

Thanks for your post Rcpilot32 it was truly valuable to this forum.

Hey skysnake, with the 46fx what prop are you using? I have been reading that prop changes even slight ones are noticeable changes to the venus. Have you experimented with different pitch/diameters and what did you find. I am sure my buddy will benefit from your knowledge on this and I would like to pass it on to him. He is actually looking more for speed out of his venus and the Saito 72 just is not doing it for him. Thanks.

The plane will climb with 50sx until out of site.
Use a performance specialty muffler or Jett engineering muffler on a OS 46fx and you will have the kind of performance you want. Or a YS 45 on a pipe. If you really want a 4 stroke go with the YS 63 on a pipe.

YS63!

I have the Saito 72 on my Venus and climbs like mad, the YS63 is even more powerful by all accounts and has the pressurized fuel system. I have weighed both and the YS is less than one ounce heavier than the Saito so there is no reason not to use the YS63.

Stay away from any OS 4 stroke for this plane as they are all waaaaay to heavy. The OS70 weighs 3 ounces more than a Saito 72, in other words it weighs as much as a Saito 100!! The OS91 is again a few ounces heavier and this will give you a 5.75lbs+ plane and that would be a disaster for wing loading.

Mine weighs in at 4lbs 15 ounces dry with the Saito 72 and it flies very light.

I might install my YS63 in the Venus at some point at least to break it in before I mount it on a Seduction, I think it will be monster with that motor.

So again I strongly suggest you get the YS63 as the best overall engine.

But if you want more weight and some more power then you should get the Saito 100.

Filip

The YS 63 will definately give you the performance you want, and keeps it light too.

Sorry zsparks, I just couldn't resist my post. hahaha. I meant no disrespect by it.