YS120 tuning guide

[raptorheli2]

seen some posts with people having trouble tuning this motor. this is not my work-borrowed from Tim Jones via RR-

What fuel?
What glowplug?
What headspeed?
What Gear ratio?

The method for tuning on the 1.20 is the same as any engine. However the Engine has been optimized to run on 15-20% Nitro. If you run on common .91 setups i.e. 30% Nitro and a hot plug, the engine will detonate. I know it sounds backwards, but you will have more power and better consistency running 15% Nitro. It likes a colder glow plug as well....A video on recommended setup is coming, set to co-inside with U.S. release.

Real quick,My personal setup:I've found that Byrons Rotor Rage 15% Masters blend runs best (The fuel you run is very important, all oil packages are not created equal)
Enya #5 plugIm using a home-made bladder tank. (this completely removes any air in the fuel system)

I would recommend a header tank. And use a fuel magnet in both tanks. This engine really does not take well to air-bubbles. If you run the above setup and still have leaning out issues, check the fuel line between the regulator and carburetor, I bet there are air bubbles coming from your fuel system. Take care of these bubbles and the engine will reward you.Also be sure the header is sealed to the crank case, I use high temp epoxy, works great, lasts basically forever, but removal is still easy. This is very important on any 2-stroke engine!

Twist the motor up to about 16,000-16,200 rpm, regardless of gear ratio.Stock 8.2 on most helis will work just fine and you will have heaps of torque, and a pretty broad power band/tuning window. I've experimented with different ratios, the engine will pull a 7.66 Gear ratio if tuned properly. (Thats a 15T pinion on the Align 700) This setup however is much less forgiving on the tune, and requires a bit more finesse to get the results you are looking for, but it is possible. I do this because I like the flight characteristics of high headspeed.

[sacko]

The Tim Jons tuning video is also a good watch, a completely different approach to tuning compared to others.

Anyone seen a guide to making this fuel bladder?

[Sao]

LIke this? PRESSURE BLADDERS

[sacko]

That looks like it

Cheers

[Guest]

I can concur with Raptorheli2 here. We are currently running a factory supplied 120SR and interestingly found it to be quite good on 20% nitro poor or 30% nitro (needs extra shim) and currently testing on 15% nitro. We will revisit 20% nitro which is what many of the factory pilots are running and a cooler plug. Pre-detonation is a very definite issue on anything >20% nitro and would no doubt be helped with a cooler plug.

We will report our finding on 15% and 20% nitro when testing is complete as we would like to see this optimized for 20% nitro.

In discussions with the factory they have done most of their testing on 15% and some on 20%. Apparently the driver is one of cost in Japan as 30% nitro is so costly and there is a move to lower nitro blends.

First impressions with the 120SR are that it is massively powerful but we have yet to get her tuned correctly. More info when we have it.

Andy

[raptorheli2]

i still have some opti 30 and a box of rapicon 30 i've just got to burn but i'll try 20% when those are away. i've not found any pre detonating with opti 30 and OS8 with stock shim. with that said the ambient is perhaps low enough now to allow this setup, may well be different in the summer months.

cheers

[Guest]

i still have some opti 30 and a box of rapicon 30 i've just got to burn but i'll try 20% when those are away. i've not found any pre detonating with opti 30 and OS8 with stock shim. with that said the ambient is perhaps low enough now to allow this setup, may well be different in the summer months.

cheers

We are awaiting a stock shim or shims as yet none have arrived but will rerun on 20% and 30% when we get them. Dave's cmment were that he could not tell any difference in power really between 700E and 700 120SR both performed really well pretty much impossible to bog.

We will try on some development fuel in due course which produces even more power so it will be interesting to see how it runs on that, cooler and smoother would be my hunch.

Andy

[raptorheli2]

i forgot to add to this, tareq also says he runs 20% on his 120's as they run better.

Tim Jones has a video knocking about using 15% and it is just silly power.

it is a shame the motor is so expensive as i feel most will not bother with it and miss out.

cheers

[jwatts007]

What needle setting are you using with 20%, I am about 1 1/2 turns out on high and middle, did wind the main into about 1 1/4 and it run well enough, then decided too set it richer to be on the safe side, like Tim Jones says seems to have a large window for tuning, I reckon I could have run 1 turn and a bit out, I am using an OS 8 and will try the cooler plugs, I also removed the header tank and this will now go back on, I have not flown it a great deal but I am very impressed by the quality of the engine, and it also very smooth running...........

[Jamin_00]

Sounds very smooth and looks like it packs a punch yours does John and it's still a little on the rich side!

Can't wait to see it once it's dialled on

[agh321]

how long are you getting from a tank compared to a 90???

[raptorheli2]

i don't use a timer so i can't say X seconds difference but i don't feel any difference flying if that helps.

maybe someone else will know but it is the same as a 90 as in you land when low on fuel :-)

cheers

[Sesame]

What about head speed are you keeping it still around the 2000 rpm area.

also whats the peak rpm or the 120?

[raptorheli2]

i run 1950 on mine.

i don't know the peak-YS keep things like that close to their chest. i.e they never tell you.

cheers

[Sesame]

obviously knowing that would help with working out the optimum gearing.
im sure people will figure it out with use.

looking forward to having a spin with one