AcroJo

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Robert, cool, thanks for the info. Its here!! Thanks to Chief Aircraft for the prompt and couteous service. This thing is built like a brick. A marvel of mechanical engineering. If your keen on these type of mechanisms, this will put a sparkle in your eye. I checked out the link provided by YS-I-Do and was very impressed with what goes into this little devil and the principle of 'supercharging'. Just wish it had a big ol' blower to stick out of the cowl. Time to get busy. Joe

lord lucan

Joe..

....Lookin & Listnin with great interest here...i'll sit at the back though...Just Two insy-winsy questions come to mind...no three actually of no concequence ...im just intreageud...( A ) I know How, but why does the fuel tank hve to be pressureised to 9 PSI ?..i'ts a pumped motor is'nt it..[8D]..( B ) what is the pressure in the Plenumn chamber @ full chat..[8D]( C )..I thought you hated Nitro. Dave

AcroJo

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Dave, I do hate nitro, more so every day, yet this may divert attention to my dislikes. This is the plane I will be flying untill building season and I may as well enjoy it. Thought of an MVVS 1.6 gasser on it and decided a few extra oz. would be better than a few extra pounds. As far as the pressure goes, I am still studying all the new info. One thing is that unlike the regulators, which opperate at 2 to 12 lbs. this is a consistant 9 lbs. Has to do with the supercharging as well. It delivers the fuel consistantly to the carb and instead of sucking fuel into the chamber on the up stroke, it is blown in. Still much to learn. Joe

Rhilluk

is that better for you.

I just get bewildered when people put such big motor's in small aeroplanes.

AcroJo

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Well, it has been a lot of trial and error, which always left me wanting more. I really want to devote my time this season to flying 3D and save the experiments for winter. I guess its all about how serious one is about what they are doing. Joe

Spaceclam

the engine does not have a physical fuel pump. i asked ys this and they said the pump they reffer to is a pressure pump that puts that tank at a steady 9 psi so that it does not matter where you put the tank. the regulator is just a membrane that is activated with a lobe on the crankshaft and plungers so the pressure makes no actual difference. cumn thru, you will love this engine. it is kinda tricky to tune but once you have it this engine will outperform all others in it's class and it's individual idle only adjustment makes it really easy to make it idle inverted at 2000 rpm forever. the idle adjustment has no bearing on the spool up so you can make the idle as lean as you need it to be and have no spool up problems.

AcroJo

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Cool, thanks. Joe

YS-I-DO

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Don't know about B & C, but the answer to A is to give you the ability to place the fuel tank wherever you want, and still have consistent results. I used 18" of fuel tubing in an Ultra Stick, and the YS ran perfectly. The same setup with a Saito 100 required a 2 ounce header tank mounted on the engine mount to stay running. Even then, it would lean out if run inverted for a short period. BTW, the tank was centered on the CG. The 9psi is for fuel delivery to the regulator, that's all.

YS-I-DO

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Spaceclam, you beat me to the punch!! What's with the "high" 2000 rpm idle? On my Lancair, with an APC 15x8, my YS would chug along at 1700! Cumn thru, you will never want another brand of 4 stroke again. Might as well sell your Saitos.

Spaceclam

ys-i-do, 2000 rpm is what the low needle is set to effect. it will work with 1700 rpm too but you will have a control dead spot between there and the 2000 mark. if it runs great, that is okay but 2000 is already pretty slow and i like it that way. you were using an apc prop which is a bit heavier so it probably acts like a centrifugal weight to bring it through compression on each stroke allowing a reliable 1700 idle. with my glow driver i could hit 1700 but alone the lowest i can go is 1900 and i try to keep it at 2000 for saftey.

AcroJo

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YS-I-DO, it sold in 15 min. Didn't have to advertize. Joe

YS-I-DO

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Whoah, Spaceclam. Just kidding with the "high idle" comment. I wasn't trying to brag. Just giving cumn thru an example. And yes, a heavier prop is essentially a flywheel. BTW, I thought that the low speed needle adjusts the mixture from 2000 down, not just a narrow window at 2000. Above 2000 the low speed needle has no effect.

Spaceclam

it is possible. i was under the impression it was set to effect the 2000 range but it may work further down, i do not know. i know you are not trying to brag, i am just comenting. it is ture though, heavier props mean more reliable idles.

lord lucan

YS-I-DO

...Ys ..thanks for that ...this has the makings of a very constructive thread please dont take any of my questions here in a negative manner ..i'd really like to understand and get to the bottom of this YS Enigma....

Getting back ... i have a pumped engine in our UCD..fine no worries ...but the tank remains at atmospheric pressure..allways ...Why does the YS have to put 9 PSI into the tank , not directly to the fuel injection system ..[8D] Thanks guys

YS-I-DO

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By pumped, do you mean it has a fuel pump, or that it is supercharged? If you are talking about a fuel pump, such as an aftermarket shaker pump or a crankcase-pressure-operated pump, the difference is in the delivery to the engine. A YS fuel pump puts crankcase pressure into the tank to push the fuel to the engine. The mechanical pump has to rely on exhaust pressure (much lower than crankcase pressure) and it's own vacuum to pull the fuel to the engine. On a YS, once the fuel reaches the regulator, it is metered into the carb. The carb is setup so that above 2000 rpm, the pressure in the crankcase, caused by the downstroke of the piston, pushes the fuel through the carb. This part of the process has nothing to do with the fuel pump or the regulator. Look at the link that I posted earlier in this thread. It will explain it in much greater detail than I ever could.

AcroJo

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LL, through experience with the 'Cline' regulated system which utilizes exhaust pressure to the regulator and then is metered out by demand of the carb, through suction. The regulator is set for 'general atmospheric pressure' without a means for adjustment. I found out, on a regular basis, that when the atmospheric pressure changed, due to various weather scenarios, the engine would react by leaning out or richening up accordingly. In the early evening this could take place as quickly as one flight to the next. Very distracting when you want to fly, rather than tinker. Afternoon flying was different, with stable pressure in the atmosphere, all settings stayed the same and the results were very reliable engine response and a smooth, low idle. Joe

Spaceclam

see, with a pressurized tank there is no need for an external regulator or a pump. the pressure pump already exists in the crankcase, why not use it rather than require two external components? also, the crankshaft is right above the regulator so why not put it there? where it is it makes it very accessible and utilizes the actual rotation of the engine to decide how much fuel gets put through. also, when you get low on fuel the fuel is forced through the clunk rather than slurping with it being sucked in.

Hercmate

cumn thru, YS-I-DO

great thread! I've had 2 flights with my YS91FZ in the UCD, swinging 16x4w prop with Model Technics Yamada Mix 20/20 fuel. On the ground I'm getting 9300rpm with lots of smoke. I'm glad i read this tonight as i was going to try leaning it out! Do you think this rpm is ok, and how does it compare (I know you're looking at the YS1.10....)

I'm also not sure about this prop, I'll be trying the 15x6 this weekend. What are you're thoughts on this?

By the way I have LOTS of smoke at idle, transition and WOT so i'm assuming after what you said leave well alone?!

Andy

AcroJo

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Somebody contact Huston, cause its time to giddyap!!!! Got the test stand squared away and the plumbing is done. Check it out.

Hercmate, that may be one for YS-I-DO or others. On my Saito 100 I tried a 16/4 and it was a bit much. Went to a 15/4. On the 110 I have a 16/4 and a 16/5 lined up. Contempo has informed me that he is swinging a 17/4 wide on his. I'm still open untill I can try it. Check out the link on page one supplied by YS-I-DO Good luck, Joe

Spaceclam

you just cut up the prop!? do it the right way man. they reccomend a 15x8 for break-in. this engine smokes a lot so you may want to do it outside rather than in the shop. you may find that you will only need 1 tank of break-in and a 2nd tank of adjustment. just in case:
to adjust the low end, trim your engine down to 2000 FLAT and tach it for 30 seconds. if it speeds up continuously, even the slightest amount, it is lean and it will eventually hit a place where it starves itself and dies. likewise if it slowly boggs up and dies it is rich. it is an air-bleed system so when you turn it clockwise it will richen it. dont touch the regulator. high end system is the same as any other fourstroke.

heavy_metal

[size=5][color=red]FULL SCALE LUNAR LANDER (A PIECE OF IRON, CARTON, ALUMINUM, PLASTIC?) OF NASA PHOTOSHOP CAN HOVER.

I HAVE SEEN HIM DO IT. I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.I HAVE SEEN HIM DO IT.

ittibitty

AcroJo

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Italian flyer is at it again. Joe

heavy_metal

YOU CAN'T STOP MY SPAMMING
YOU CAN'T

Rhilluk

becareful running it in on the bench. YS like to run in in the air.

AcroJo

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Clam, chill. Thats my break in prop, it has spun on many engines. My plan is to fill the shop with so much smoke that I pass out and hopefully when that paramedics arrive the engine will be broken in. I could use the rest. Joe