Who's builiding OS 90 Motors?

[Mike J]

Iv'e got a new Os91szh pumped hatori sb18 It runs really strong, but the power I want and need just isn't there. I've got inflight needle control so the motor is tuned and running its hardest the whole flight. Runnning cool power 30% with .016 head shim, thinking about dropping that down to .008, or running 40%. Anyone running 40%? After Watchin videos of the pros 90's I need my motor to run like theirs do. I know they have great collective managment, but mine is pretty spot on. Anyone know who to send one to? Or someone who builds them can tell me what to do? I just need the R&D behind it, all tools and mechanical abilities are here, I just dont want to have to go through 10 sleeves trying to get it right. Dial indicating the fan gets to be a pain after a while:D Thanks

[Turbo Dave]

Do a search in Helifreak for the OMI Cline Mod, Thats about all the power you can get from a 91 engine.

If its still not enough I eally dont know what you are aiming for out of your heli.

[Mike J]

Flown the pumped os91 szh? The Cline mod could be an option. Would like to hear from someone who has flown both motors. What I'm looking for is, to sustain 1950HS as best as possible.

[Turbo Dave]

I Fly a non pumped 91SZ and a YS91 in a Stratus and can do most manouvers without loosing headspeed, I can bog them both very easy if I overpitch the head, But if flown correctly I dont have any issues they are very fast and very responsive.
As unlimited as these things are they still have limitations if you know what I mean.

[Mike J]

Sure. I can fly the thing all day doing many maneuvers without bogging it. Problem arises when I start doing very fast pitch pumping moves. Can you do all the moves very quickly without loading the head up, even a little? In normal 3d you have the time to completely unload the head, or if the move is big enough you wont load it at all. But in real tight moves, especially real low, power is paramount. With very good collective managment if you do moves fast enough with out pausing for that split second to "breathe" the motor it will load up (just a little bit) Resulting in a (small) loss of crispy-ness. Please dont misunderstand me when I say bogging as its a miss on collective managment, I'm just looking for that real fine edge on performance. I realize that R/C helis and 90 size motors have limitations, but I'm not there yet. Theres more power in that motor.

[Turbo Dave]

Im hearing ya with the power craving, MORE MORE MORE!!!
But I dont know if your going to get what you after, From what I have read the OMI Cline setup is the biggest stump puller out there.

[DavidH]

As far as I know. The only mods done to any of the Cspecs or SZ's is carb work.
The SZ pump you have you will just have to fly it the way it is unless you want to buy a new carb. OMI does not do anything to the pumped engine carb.

After Watchin videos of the pros 90's I need my motor to run like theirs do.

Your motor can run like theirs. But the model is still not going to fly like theirs. Unless it is one of them flying it. The pros as you call them. There cyclic and collective control is what allows them to utilize the power of the motor. I have seen them take someone elses machine that said there motor was not producing power and fly it just like it was their own heli.

You options for the SZ if you want to use a Cline. You will have to get another carb. Either a 60K off a Cspec or a carb off a non pumped SZ. The 60 K carb OMI can bore it to 10.8 mm and add the Cline and do a needle modification. The SZ non pumped carb OMI just adds the Cline and does a needle modification. The Non pumped carb is already 10.6 mm bore.

David

[Dr.Ben]

David is really right here. If you have a SZ running hard on the SZ version SB muffler, there just isn't much more power left to be had. The big bore OMI C-Spec might has a small edge, but nonwhere near what you seem to be looking for. See if you can make it out the the Vegas fun fly and let Alan or Danny fly your model. See if they think it's underpowered. I suspect it'll gain 1/2 hp the moment either takes up.

Ben Minor

[Mike J]

Im aware of their superior collective managment and flying ability, really. But just watching their machine take off at 13 degrees of pitch, mine pulls it, but not like that, close but not quite. Trust me I've seen pretty much every video of Alans that there is on the net (atleast what I can find) His heli runs a bit more "cackly" that mine does, you can hear it at idle. If he flew my Fury he probably would make it look better, 1/2hp better idk about that. I suspect if he flew it he would definatly say that it was NOT underpowered, but it could be better. Alan does bigger, very impressive moves, he can do alot of low ground work as well. I tend to be a bit more aggressive on the sticks (not in a bad way, im not just jamming the sticks around, I do have a clue), i'm just lookin for that fine edge with this motor. All people have done is carb work? I realize the obvious importance with the carb, but no one is playing with port timing, lightening the crank, rod etc etc? I'm not new to the R/C world or Nitro motors. There have always been people making good power, then their were the team guys making GOOOD power, I suspect you know which club I want to belong to.

[Dr.Ben]

I can tell you pretty much for a fact that the engines that are being run today are not the heavily modified, blueprinted 60's of the past. The crank counterweights need to be as heavy or heavier than they already are to keep the engines smooth. The pistons don't leave a whole lot of room for lightening as the first generation 70 owners can attest. The port timing on the OS engines is already that which will allow the use of a tuned exhaust, though the SZ's intake timing is a bit more restrictive than the C-Spec's and thus really needs a higher rpm and different muffler to run well. It could be more radical, but how picky are you prepared to have the engine be to pick at an extra tenth or two of hp? Are you running the SZ specific muffler? If not, your engine is not going to dig as hard as you want it to. The main thing the Cline mod gives you is dead consistent needling that allows the engine to be tuned for maximum power without a concern for a lean run coming out of nowhere. If you don't hqve a Viperhead on your engine, you'll loose a little bit of smoothness and perhaps power since the engine can be run a little harder with the superior cooling the head provides.

Ben Minor

[Mike J]

Currently I'm running the sb18 tuned for the SZ. I Just bought a new Mp5 tuned for OS, I've been doin some reading and people seem to be very happy with that pipe running at 1925-1950, which is exactly what HS im running. In the beginning with the pumped os I was having leaning out problems.....heli would be running great then just lean out, that seems to be in order now, it runs consistent. The Cline mod might be somethin for me to try, I'll have to get a hold of a non pumped Os carb and backing plate. and send it out, changing to a viperhead might be an option as well. Thanks for your input Dr.Ben, I'm gonna try that new pipe tomorrow provided I have some good weather.

[DavidH]

There have always been people making good power, then their were the team guys making GOOOD power, I suspect you know which club I want to belong to.

The motors I use come thru the same person that most of the top pilots that using OS engines come from. All that is done is some carb work by James at OMI. My Stratus doesn't look like it has as much power when I fly it either. But when I hand the transmitter to one of those guys. It looks like it gained some power. I have been doing this also a while. I know I don't have the cyclic/collective technique that the top 3D pilots posess.

David

[Mike J]

Have you flown the pumped Os and compared it to your cline OS?

[ChrisLaFollette]

My SZ with cline from james (OMI) will pull 13 +/- pitch all day long and 9 cyclic and not bog unless I just jam the sticks some dumb way. If you hammer it, itll pull and not load down, this thing runs like a train on crack. Im running the OLD style V2 blades on mine also...

SZ / 60m-c carb w/ cline and an SB17. Im not even using the "best" pipe for this engine and it still pulls hard!

I would have somebody (one of the pros) check over it and fly it for you and see what they think. Your either expecting too much or your motor isnt putting out the most it could, the most you can do with the engine is put a cline on it and do some porting work. Thats about it. As far as ive seen, I think personally, though I could be wrong, the electric machines setup "correctly" for your flying style pull a lot harder than the glow machines, might wanna give the E-World a try.

[Mike J]

Oh I know the E-machines have absolutly crazy power on 10 cells, check out this video.... http://www.madmanrc.com/files/Madmans_Bang_My_Heli_Vol_9_Ultimate_Trex600_Music_ Only.wmv 15 degrees of pitch!!! The more and more I read I'm finding most all the guys that are flying really hard are running the Cline, I might have to give that a whirl. I dont rewally have any interest in big E-helis right now, batteries are ridiculously priced. Beyond the cost is the shear lack of flight time, the setup you see in vid I just posted only gets 3 min flight times, and thats on a battery that costs 500$ Not to practical for me. From the sounds of it Chris I want my motor to pull like yours. The pumped OS really does pull hard, but I guess all the vids I'm wqatching are with the Cline setup, 13 with out bogging would be nice. :D

[DavidH]

Have you flown the pumped Os and compared it to your cline OS?


Yes, I took the pumps off and went back to the Cline setup. I just like the way the Cline setup performs. It is reliable from day to day and week to week. Runs consistent and I very seldom have to touch the needles.


David

[Mike J]

It is reliable from day to day and week to week. Runs consistent and I very seldom have to touch the needles. That would be nice, Ive got the pumped OS running really well, but from day to day it can be a few clicks off, it depends alot on the air, this motor does seem really sensitive.