Some YS 91 SR questions

[derelict]

Hi all..

I've just received my last part to finish my t-rex 700 build.... the YS 91 SR.

So shortly a few questions came up (sorry if this is answered somewhere else.. but I couldn't find it)

- on which needle to I have to apply the carbsmart servo to ? (hover which is longer, or high which is shorter) ??

- is it just me..or are the two needles quite loose and easy to turn even with that retaining thing ?

- the manual says to unplug the pressure tube while filling... is that really necessary ?

Thanks for any help !

Marcel

[p00rboi]

On all to the setups that I have seen using the ys the carbsmart is used on both the main and hover needles configured like a push/pull set up.

My needles seemed quite loose also. This becomes a moot point once the carbsmart is installed.

You must unplug the pressure line while refueling or you will showered with fuel. If not as you refuel the air that is in the tank creates pressure in the pressure line against the check valve leaving the air no where to go but out through the line that you are fueling through.

[derelict]

thank you very much for the info.

can you point me at some pictures or threads about the push/pull method ?

@BOB:
i've seen that you've installed the ys on the aurora... with what carbsmart installation did you end up with on the aurora ? (haven't seen all the videos as i don't have an aurora ;-) )

Greets

Marcel

[Finless]

The YS is running SO WELL that I have NOT installed a carb smnart on it! In my opinion it is NOT needed... Oh and as for the push pull thing on high and mid needle... Seen that locally and it doesnt work! At least it did not for 2 people in my area that tried it... BUT I guess it depends on your flying but the hjigh needle is what needs to be controlled on an OS... If yout fluing in the mid range all the time based on flying style then maybe that is a good idea.... From what I have seen having it control both just doesnt seem to work well.

Bob

[derelict]

Thanks bob!

I think i try it without carbsmart first to see how the engine goes.... and use the carbsmart on the HIGH needle as needed afterwards maybe.

Have you secured your needles on the YS somehow... or do they hold up to the vibration well (haven't flown my t700 yet) ? for me they feel quite loose!

Greets

Marcel

[Finless]

You dont have a spring retainers on both your needles? On mine I do and no they do not move....

Bob

[derelict]

i do too... but are quite loose compared to the needle on my os 50.

i was just concerned about the vibration on a 90 sized heli.

marcel

[PIGROLL]

I am planning on using an SB17 on a 91SR and can anyone give me an idea of what I will be missing without the SB19?Will it work properly or not?

[Finless]

OK well if your concerned remove them and BEND them down a little and re-install... Should tighten them up no problem.

Bob

[derelict]

sorry <smile>... i have already tried that, too!

But nevermind... i guess the problem is more likely me but that spring :YeaBaby::YeaBaby:

thank you very much... have a nice day bob !

marcel

[CoronaL]

I am planning on using an SB17 on a 91SR and can anyone give me an idea of what I will be missing without the SB19?Will it work properly or not?
you'll be missing 2. Sorry I don't really know other than I think the SB17 was tuned for the OS motor and the 19 was specifically tuned for the YS SR from what I read. It would work I'm sure, but might put the motor out of it's ideal powerband a bit. Might be a good question for the motor/muffler section and the YS gurus.

Also, re: carbsmart on YS. I don't think it would be needed. Like Bob said, once you set a YS, they are pretty much going to run consistent. That's the beauty of that motor from what I have been told. The non regulated OS on the other hand would benefit I'm sure. Myself I will be using an Iron Bay regulator on my OS91 when I use that motor, making it YS like in the pressure regulation.

[derelict]

Thanks corona for pointing that out... it's good to know that the ys seems to run fine even without the carbsmart !

But I'd like to mount a header tank just for the peace of mind.... will that cause any side effects with the pressurized system of the ys motor ?

Greets

Marcel

[derelict]

maybe i should update.... i don't want to start a header tank discussion again.

i'm using a fuel magnet in the main tank and the only reason i'm running the header tank (without a fuel magnet) is that i don't trust the fuel magnet completely.

- do i need a second fuel magnet in the header tank ?
- will this setup cause any problems with or without the header tank ?

Secondly... is there a "break-in an ys 91 sr motor how to" somewhere... as the manual is very limited about that topic?

Thanks for any help guys

marcel

[DavidH]

You don't need a header tank with the fuel magnet in the main tank. The fuel magnet will allow every drop of fuel to be used in the main tank. And the engine will only go slightly leaner as it runs out of fuel. Most of the time my engine gives no sign before it quits from the tank being out of fuel. It will just quit like it is cut off. A header tank is NOT useful when the main tank has a fuel magnet. The name of the fuel magnet is the ELD. That means Every Last Drop. And that is exactly what the fuel magnet does is get every last drop of fuel out of the tank.

David

[derelict]

thank you david!

i've read about that in another thread here on HF.... the reason why i still would like to have a header is because:

- i sometimes miss that the main tank is empty (and i'm not that good with autos yet ;-) ) and therefore rely on the header tank.
- i would like to ensure that the motor still gets fuel eventhough the clunk in the maintank got stuck somewhere

Is there anything wrong with using the headertank with my current setup (ys 91 sr pressurized, omi fuel magnet main tank, header tank with normal clunk) except that it isn't really needed ?

Greets

Marcel

[BiggerDanno]

I toasted an engine that had a fuel magnet.

When it quit, I autoed to a semi-safe landing (broke one skid support). The fuel level was at 1/4" in the main tank, didn't have a header. I was flying around FF only. After it was on the ground, I tipped the bird forward like it was during FF, the clunk was completely out of the fuel. While the fuel magnet may save you from momentary fuel starvation, it does nothing for extended periods during which time your carb has sucked all the fuel out of the magnet.
I'm putting a header tank on with my new engine...

[derelict]

that's exactly what i would like to prevent! but i'm not sure header tank like setup will cause any side effects with the ys setup?

Greets

Marcel

[BiggerDanno]

So you will be pressurizing two tanks instead of one, I don't see that causing a problem.

[Arcus 4]

I run a header tank with my YS 50ST. No issues. I plan to run one on my 91SR as well.
I don't know anything about the Carb Smart but I have not tweaked the needle on my 50 since it was set. No issues encountered. Keep in mind I am not a 'stick banger'.

[DavidH]

I toasted an engine that had a fuel magnet.

When it quit, I autoed to a semi-safe landing (broke one skid support). The fuel level was at 1/4" in the main tank, didn't have a header. I was flying around FF only. After it was on the ground, I tipped the bird forward like it was during FF, the clunk was completely out of the fuel. While the fuel magnet may save you from momentary fuel starvation, it does nothing for extended periods during which time your carb has sucked all the fuel out of the magnet.
I'm putting a header tank on with my new engine...

The clunk being out of the fuel with 1/4 tank of fuel is not the fault of the Fuel Magnet. That is because the clunk line was not set up properly in the tank. I use Fuel Magnets in my tank. Every drop of fuel is gone from the tank before the engine will quit. It doesn't matter what orientation the heli is in at any time. Also know several pilots that use the fuel magnets with the same result.
If the clunk line is set up correctly where the clunk ( Fuel magnet) will reach everywhere in the tank. It will work correctly.

[BiggerDanno]

The clunk being out of the fuel with 1/4 tank of fuel is not the fault of the Fuel Magnet. That is because the clunk line was not set up properly in the tank. I use Fuel Magnets in my tank. Every drop of fuel is gone from the tank before the engine will quit. It doesn't matter what orientation the heli is in at any time. Also know several pilots that use the fuel magnets with the same result.
If the clunk line is set up correctly where the clunk ( Fuel magnet) will reach everywhere in the tank. It will work correctly.

Let's see how you make your clunk reach the front of the tank, that's where the fuel was.

I've never seen one that would reach the front of the tank.

[DavidH]

I use fuel line that is flexible. I don't use fuel line for a clunk line that is the same as used for plumbing from tank to motor.

This is what I use. It is very flexible, has not kink and flows plenty of fuel.
http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA115-65

It has gave great results for many years. I don't know who MA gets it from. But it is some of the best tubing I have used for a clunk line for the 20 yrs I have been in the hobby.

David

[BiggerDanno]

Sorry, not buying it.

Let's see a pic of your clunk at the front of the tank with the heli tilted forward about 10-15 degrees.

[DavidH]

Well here is the fuel tank I use. Never had a problem with getting all the fuel out it with fuel magnet.
http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA126-53

I do mostly F3C contest type flying. So the model is doing most straight and level flight when going out to turn around to come back and do the maneuvers.

Go to this thread and look at the pictures. I didn't see any header tanks being used on any of the contestants helis. And they have the heli in all kinds of positions during there flight. I know about 50% of them maybe more are using an ELD Fuel Magnet. And I have watch them fly till they run out of fuel. It takes some time to set up a fuel tank so the clunk will work correctly but it can be done.
http://www.runryder.com/helicopter/rrTV-Photo/contest/XFC2008/

There really is only two reasons to use a header tank.
1, More Fuel Capacity
2. Pilot needs to see the fuel level because he doesn't feel comfortable flying unless he can see fuel.

I have used a 4 oz header tank. Because with the stock tank on the model, I didn't have enough fuel to get thru the maneuver schedule in F3C.

David

[BiggerDanno]

I've run mine out of fuel before too, but not when doing continuous forward flight where the tank is always tilted forward.

The 3d guys are also not in this attitude (tilted forward) for long.

In order to extract all the fuel from the tank in this attitude, the clunk would have to be able to go all the way to the front of the tank, and do it with a 10-15 degree tilt. I don't see this happening.