You asked how much oil came out of the vent port.
The fuel tank is 360 cc the bottle is 500 cc.
The engine is 300 rpm fat at WOT, the LSN is set as lean as possible to have good quick transition to WOT.
50% of the tank was run at WOT the rest was run at mid throttle and maybe three minutes at idle.
I would guess a little less than 1 oz is in the bottle (29 cc).

[edit here]
The fuel, is a mix of 1 gal Cool Power, 3 gal Wild Cat, and 1 gal Omega all of them are 15% nitro.
This mix yields 17.6% oil (1% castor. 16.6% synthetic), 15% nitro, 67.4% methanol (these numbers are rounded to the tenth).

That's rather interesting. Assuming 20% oil, there was 2.4oz of oil in the tank. ~40-50% of that made it past the ring into the crankcase. This assumes the crankcase was already at the average running oil volume and that there was no extra oil in the crankcase, such as after run oil. That's actually quite a bit more than I expected. In that case, I think we could run much less oil than we do in four strokes.

Hiside,
You may want to mention what brand of prop your running if you havent already. Were seeing that the 125 will turn a MA 16x6 at 9k where the APC 16x6 is in the low to mid 8's. APC is a more efficient prop overall.

Also I dont know where the differences are but my Saito 120 will swing an APC 16x6 a 1000 RPM more than my 125's will.

I did not think about posting the fuel details, sorry. I will also edit the earlier post.
There had been no additional oil added to the crankcase between engine runs.
The fuel, it is a mix of 1 gal Cool Power, 3 gal Wild Cat, and 1 gal Omega all of them are 15% nitro.
This mix yields 17.6% oil (1% castor. 16.6% synthetic), 15% nitro, 67.4% methanol (these numbers are rounded to the tenth).

Hi Chas,

Wow, I am stunned by the amount of stuff that made it out of the breather, thanks for doing that. As you say, that's something like 40% by volume.

Togatoga and I are now wincing a bit if this is how much oil we are plumbing back into the inlet manifold. I wonder (hope) if some of what comes out is unburnt fuel!


Hi mvallyman,

Prop was an APC. My prop box is almost exclusively APC, makes it easier to keep track of what works on what and having a spare.

I'm really looking forward to getting the engine back for three reasons:

: I get to find out if I am a muppet
: If it pulls 8.7k - 9k on a 16x6 and 20% then I can bolt it to my Adrenaline and go flying.
: If it is in the low to mid eights as you are seeing, then all the reports about this being an engine approaching YS performance are a bit optimistic, and it's probably not going to give the flight performance I want. My aged MKIII OS 120 surpass manages 8500 on a 16x6 and 5% nitro. This still makes me happy though, because I can justify to my missus buying a new YS110S...

Quote: "Also I dont know where the differences are but my Saito 120 will swing an APC 16x6 a 1000 RPM more than my 125's will. "

Really? There is no doubt that the newer Saitos are quite "cammy" and only come "on cam"* at around 8.5k. My 82a will swing a 14x7 at about 8700, sounds good and behaves itself. Change to a 14x8 and the rpm drop drastically to around 8k and you can just tell it doesn't want to know. Maybe the older 120 has less agressive cam profile and is better when loaded right up.

HS

* Not sure if this terminology is global or not. I picked it up from my brother who is a specialist in the old Lotus twin overhead cam engines. These days they are eeking 250+ bhp out of a 1700cc block, normally aspirated. Not bad for a design which is basically 50 years old. But these engines are very "cammy" as he calls it, they cough and splutter all the way to about 5000rpm where, within a few hundred rpm, they clear and pull like stink.

which reminds me of an amusing story. In the paddock at a touring car meeting, a member of the public asked him if the car he was fettling was fitted with a a rev limiter. "Yes" he replied, "It's quite simple and very, very reliable. At 9200rpm, the crankshaft breaks."

The fuel tank is ~12 oz and there was ~1 oz of gunk that came out of the vent tube.
It was thick, I don't think there is much unburnt alcohol in it.

LOL ... I guess its all perspective on what is a lot .... I was thinking that does not look like all that much to wipe off the plane.

And the answer is...

Just spoke with John Haytree who has stripped and rebuilt the problem 1.25.

He said the engine was in lovely condition, everything to tolerance and all looking correctly run-in ... except for the piston, which had two VERY high spots on the skirt making the piston a poor fit in the cylinder. Apparently, in a Saito, the piston should be a very free fit in the cylinder, the ring is what seals it; this is why the skirt often looks worn because there is a degree of piston slap in normal operation.

He believes that the friction from the two high spots was causing a localised heat build up / increased friction cycle leading to the fall off in rpm. The only thing he can think of is the piston may have been dropped or whacked in the factory, distorting it slightly and resulting in the high spots.

But all is well now and the engine is winging its way back to me. I'll post some figures once it's back on the bench. Maybe I'm not a muppet after all.

HS

:-)

Well good.

We are glad you got to the bottom of the problem. You couldn't have had a better person working on it.

That's great. It wasn't the mods after all.

Just had chance to nip out and give it a quick run.

On 15% nitro / 20% klotz and an APC 16x6, I'm getting a steady 8500rpm (stock muffler, YS 4c plug). Still don't have a 15x6 to hand so couldn't try letting it rev a bit. But this seems to be in line with what other people have reported for that APC.

I did try with and without the breather connected to the inlet, no measurable difference in rpm. Togatoga will be happy :-)

No sign of the rpm sagging, so it seems that JD Haytree has worked his magic again.

I did manage to detonate and throw the prop once, a second or two after transitioning from idle to WOT. A quick thank you to the patron saint of conrods and a tweak of the slow running needle and I never saw this again.

Finally, 8500 on 16x6 is unlikely to be mega for 3D on an Adrenaline, so after all this I'm still gonna put a YS110 in it!!!

HS

HS, in my book the 15x6 is a good prop for the 1.00, its even too small for the 1.15, You should see 9,000 with a 15x8.

Hi HS, thanks for posting the result- I reckon in the end, real world figures count, not theories. I remember Brian Winch doing this mod to his engines many years back and recommending it to readers.
I tried a 15x7 apc with the 125 and found that it didn't perform as well as the 15x8apc.The engine was louder but the plane didn't fly as well! I'm going back to the 15x8.I agree with hobbsy, I think the 15x6 is too little prop.

Thanks for the update highside.

Hi, can confirm 8900 on an APC 15x8.

I've just dropped a YS FZ110S onto the testbench, same fuel (15% nitro, 20% klotz), same plug (YS 4C) and same exhaust (Hatori short muffler + header). On 16x6, I'm seeing about 9500 rpm (c.f. 8500 for the Saito), still not yet run-in and quite rich. You get what you pay for, I guess :-)

Found a nice home for the Saito in my father's Cessna. Doesn't need ultimate grunt and I think it'll make a nice pairing.

HS

Quote:

ORIGINAL: highside

I've just dropped a YS FZ1.10S onto the test-bench, same fuel (15% nitro, 20% klotz)...

HighSide,


The YS is very likely to run badly on that fuel...

Unlike OS (and its clones) and Saito engine, that will run nicely on fuels containing 15% nitro (or even less), YS engine require 20% nitro as a minimum, to run as intended.


They are designed for high nitro percentages, rather than this being a convenient option...

Also, are you talking about Klotz Techniplate?... Knotz BéNOL castor oil is not the ideal oil for a YS. 2% of this oil is OK, but not all castor, if you want to keep your maintenance to a reasonable frequency...

On 15% nitro these engines may need to be leaned down excessively, to the point of overheating, just to get the proper mixture strength.

I believe the YS 1.40 Sport is their only engine for which 15% nitro is within the recommended percentage...


Testing your 1.10 on that fuel will prove no point.

Hey DZ,

Yep I know...I usually run my YS's on either Model Technics YS blend (20% nitro, 20% techniplate) or Bekra 30% (which has, I think, 21% synthetic mixture of techniplate and EDL whereas the 20% bekra has only 18% synthetic). But I was just making a comparison for my own sanity, so I gave the YS a quick run on the same fuel I'd been putting through the Saito (which was klotz techniplate).

Having said that, the current operators' manual for the YS FZ110-S does recommend 15% to 20% nitro and 15% to 20% synthetic oil, and I know a couple of people running on 15% nitro with no problems at all. Not surprising they are doing this, my LHS has just had to hike the price of YS mix to 31 pounds a UK gallon! That means every flight of my 2m F3A costs over three quid in fuel!!

:-)

OOPS!


I just saw that you did write it is the YS1.10FZ-S...

They probably hiked the C/R a little, to allow the engine to run properly on a bit less nitro...

But from what I am hearing, the the 'bottom line' is that the FZ was a better engine than its supercessor FZ-S.


The old saying 'If it ain't broke - don't fix it' was apparently not followed by YS...

After all the boogaboos with the first batch of 1.10FZ engines (airbox gasket?) were overcome, it had become a very good engine to own.
...putting it in the 'ain't broke' category...

So, why did YS select to 'fix it' with the 'S' model?

No worries :-)

Well, the S manages a few more RPM if urban myth is anything to go by :-)

I'm pretty sure of one thing - YS must be seeing their market eroded by electric. Anyone serious enough to spend 600 pounds on a 170DZ and then add a carbon pipe and header is not going to be put off by the LiPo etc. costs for F3A, and the performance of electric is certainly there. I reckon this is why they have finally done a CDI unit for the DZ series. I think even more pressure is coming too, I know probuild have designed an F3A airframe around a 3W petrol engine and are pleased with how it compares to a 4C glow in the way it flys the airframe; bound to be cheaper in initial outlay and certainly in fuel.

So, YS must seriously be looking at how to upgrade their range to keep them selling.

Not heard anything bad about the new 110S, what negatives are people claiming?

HS

Quote:

ORIGINAL: highside

...what negatives are people claiming?

HighSide,


I don't exactly know...
It is just that people who currently own, or have owned the FZ; and purchased the newer 'S' model (so they can make a fair comparison), say it is not as good...

I can ask them and write again.

The main difference is the fuel metering system

I thought it was for reliability and ease of service?

That you will not notice any difference in power between the n"S" model and the regular "FZ"

Hi, I bought a new Saito 82 and it would not perform at all. So I sent it back to horizon and the found the SPRAY bar was insatlled back ward in the carb at the factory.

Hi, I bought a new Saito 82 and it would not petfom at all. Sent it back to horizon and they found the spray bar was installed backwards at the factory. My did the same thing. Hopr this healps.
Tom