oskartek

I have been out of the hobby for about ten years and am getting back into flying. I have purchased a YS .91 AC motor, this is my first four stroke. Is it a suitable motor for the Tower trainer 60? and is 30% nitro and 18% synthetic/castor blend a suitable fuel to run? Any input is appreciated, Thanx.

ChuckW

Is it suitable? It might just fly the plane into orbit!

A .91 4-stroke is generally suitable for a "60" size airplane. The YS is no ordinary 4-stroke though. Even the older .91-AC makes some serious power. I have one in a Top Flite P-47 and the plane really gets out of its own way in a hurry.

For your trainer you could probably get by with an even smaller "ordinary" 4-stroke.

If you do use the YS, remember that the left stick moves backward too... manage the throttle.

The fuel will work but that high nitro content isn't absolutely necessary. Most people run 20% in the YS's. I even run 15% in them. People claim it won't work but I do it. I may not get every last bit of potential out of the engine but they are still a powerhouse compared to other stuff. I don't like Castor in 4-strokes either although some people might disagree. I've found that it gums up and results in things like stuck valves.

JET FX

Not the first engine choice for a 60 trainer ideally, although in this case if youve already got the YS and want to use it I would say over prop the engine a little ie go with a larger diameter/finer pitch prop. 15% nitro is fine also Ive run it for years in my 91AC with great performance... Without doubt one of the best 4 stroke engines Ive ever owned and amazingly reliable idle and super fast transition. Performance of the YS 91 AC is on par with many normally aspirated non supercharged 120 size 4 strokes...

turboratt

i agree with the rest but dont use 30 % at the max use 20/20 fuel
you would be better off holding on to the motor and just get a cheap 91 like a magnum or thundertiger
but you can use the ys just make sure your fuel line are done right

Texastbird

How about a nice gentle symmetrical wing Goldberg Tiger 60? Its a large plane that will love that YS and it is as easy to fly as most trainers and will do some aerobatics when you are ready to try some again. You will be surprised how fast the old flying skills come back to you and the Tower trainer will be very boring, very soon. We have a fellow that has it as his second plane and he flies it like a pro. My old friend has one too and it is very forgiving and lands like a breeze.

oskartek

I thank all y'all for the advice, as I haven't yet purchased the trainer I will try to find one that is more suited to a 1.20 motor . Any suggestions?

MikeL

My Feedback: (3)

How much flying did you do in the past? If you're going to need help from an instructor, be sure that you know how to operate your engine and are confident in being able to do that. Plenty of guys have never used a YS, but are aware of their reputation (deserved or not) for being complicated and more difficult than a "normal" engine. If your 91AC is used, it may or may not have some setup issues. More than one YS has been sold because the original owner couldn't bring himself to just follow the instructions that came with the engine.

oskartek

I was originally flying first with all .40 size aircraft, starting with a Tower Trainer then moved on to an Ugly Stik then decided to build a kit SIG Four Star with an OS FX .46. Flew the Stik and the Star for about a year and a half. When I decided to get back in I decided to go at least .60 size or larger after trying a friends .40 Thunder Tiger Trainer for a couple of flights.

oskartek

I do not want to sound arrogant but the YS motor does not intimidate me as I have built and tuned racing two and four stroke motorcycles, I think I will be able to work with the ins and outs of this motor ( I hope).

oskartek

Of course it's what you learn after you know it all that really counts

ChuckW

That's when I like to by them, fix whatever the guy screwed up and have a nice running engine.

ChuckW

It isn't that complicated but a lot of people do seem to mess them up. First thing to make sure is that the fuel tank is assembled correctly with no leaks. Then make sure the fuel and pressure line are hooked up correctly with the check valve in the pressure line in the right direction. The engine must also be in good shape with no leaking gaskets/seals and a good regulator diaphragm. If all that is in order they are no different than most other 4-stroke internal combustion engines.

If you are half way mechanically inclined, which it sounds like you definitely are, and you can read and pay attention to details then you'll have no trouble. In fact you'll end up with one of the most reliable, powerful engines around. They are a true pleasure to own in my opinion.

Barry Cazier

My Feedback: (17)

YSs are my favorite glow engines. They clearly have 20% more power than anything else in class. The higher you go in altitude the more difference there is because the YS is supercharged. I fly at 4800' so I love the YS power. I have several 110s and a 63. I can honestly say I had a terrible time setting my first ones up. And I did it by the manual. Which states to not touch the regulator and to leave it at factory settings. Well, that's what I did and I had a deadstick everytime at the end of the flights on landing. I ended up opening the regulator about 1/4 turn and that was it. Simple from then on. The other thing I noticed is after you finally get them tuned, they stay tuned. Don't mess with it. Just fly it. The 91 is a great engine. Also, check your valve settings. I think 4mm is the proper clearance. This changes fast during breakin. But once you get some time on the engine they don't require much adjusting either.

I use 30% Cool Power (22% oil) Makes the engine transition smoother and the idle will be more reliable. And because it makes more power you don't necessary have to use the extra power. I find I get better milage with the 30%. So it really isn't that much more expensive. And it makes tuning/running the engine all the better.

Ahhhhhhhhhhhh.....YS......You love them, till you don't.

Thanks
Barry

JET FX

Well depends on if you like to build? The all time best trainers in my opinion are the Carl Goldberg Falcon 56 and Senior Falcon, I learnt to fly R/C on the 56' back in 1978 powered by an O.S. 40. The Senior Falcon is a 'scaled up' 60 sized version, kits- http://www.earlyrcmodels.com/index.html and plans are still around for this as is possibly even plans for a Falcon 120 version. If you want an ARF only the 56' is now being produced by CG. Bottom line is that I would advise looking for as similar a design to one of these trainers as possible. Maybe consider building a kit or putting together an ARF and also pick yourself up a good quality Flight Simulater for your computer to practice on as well...

Cheers- Marty


http://www.rcuniverse.com/forum/m_87...tm.htm#8765637
http://www.carlgoldbergproducts.com/.../gbga1050.html

Zeeb

My Feedback: (41)

Well I'm gonna second some of the comments you've already received in that the YS is a great product, I'd consider a different airframe or maybe even save the YS for your second plane and go with a simpler engine. If you're not really into trainers, lots of folks like the Sticks of various sizes and an OS will get you into the air quicker, won't hurt as bad if it meets an untimely end either.

While you seem to have the background, like any other high performance engine there are certain tricks to the tuning process and the toubleshooting process is different for a YS over other engines. While it's not supported by anyone from the distributor anymore, there is a YS support forum with LOTS of information both from past entries made by the support folks to some pretty savvy users who now answer most of the questions.

Like Barry, I fly at 4500' ASL and the YS is really a horse at altituded compared to other glow engines. The tuning isn't difficult but you have to play by the rules and the documentation you get with the engine isn't exactly comprehensive....

While some folks do run 'em on less than 20% nitro, 20% nitro and 20% synthetic oil are the minimum YS recommends. I'll say that I agree with Barry in that the little beasts really like the 30% nitro and you'll find that not only are they better performers on 30% but they are easier to tune and will idle at a slower RPM which is helpful because it makes it so the model doesn't taxi off or land long when the engine is idling too fast.

If you're so inclined, I'd suggest you spend a bit of time over on that YS forum and you'll pick up a bunch of helpful hints and tricks;

http://www.rcuniverse.com/forum/forumid_197/tt.htm

oskartek

First off I would like to thank all of you for the excellent advice given. For Barry and Zeeb, the club field that I will be flying at here in Cedar City is 5800 ft.(1766m) Alt. so supercharging is definitely a plus. I think I may go with an OS .75 AX (which with the club discount I can purchase at my LHS cheaper than Tower) on the Tower trainer and save the YS for the SIG Four Star 120 kit I have planned.
Thanx, Oscar

oskartek

Today I bench ran the motor outdoors ambient temp. 40F. It took a few tweaks to get going including backing out the regulator screw 1/8 turn. The throttle response is very good. I ran about 20 OZ fuel through it, the idle is a little inconsistent(2100 to 2250 RPM) but I think that will clear up after break in and flight tuning. Will clean it up and pack it away until I have the oompa loompas to fly the Four Star. By the way ChuckW and Marty, I'm gonna start trolling for suckers, oops, unfortunate frustrated YS owners who want to unload their motors cheap! 

                                                                                                                                         Many thanks for your help,  Oscar  
             
                                                                                                                                               

ChuckW

Having to adjust the regulator must be related to the higher altitude. I've never had to touch one at all. Makes sense though, my old carbureted car used to run like crap if I drove it up into the mountains.