RunRyder RC
 2  Topic Subscribe
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 975 views
Scorpion Power Scorpion Power
HelicopterEngines Plugs Mufflers Fuel › 91ST Over Pressure
03-20-2009 03:22 AM  8 years agoPost 1
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

OK time to ask the experts

I'm trying to tune my 1st 90 that had been run on CP30, to CP15 (90ST in a 700) and fiddling w/ 2 needles for the first time. I think I'm close, but I'm finding out how sensitive the YS MSN & HSN are.

On the last test flt today, I turned the HSN maybe 1 click too much; when I autoed down I could tell she was a bit hot at 237 deg F on the head (that one click made all the difference).

Anyway, as the heli was sitting there, I heard a couple 3-6 slow drops of nitro hit the hot pipe, making a hissing sound. When I disconnected the tank pressure line, it was under a lot of pressure- sounded like letting air out of a car tire.

As usual I refilled the tank, cranked her, and then pinched the fuel line shut for cutoff...all normal.

But after the heli set on the bench tonite for a couple hours there was a pool of nitro maybe 4 in in dia under the heli. Obviously, almost imppossible to tell where it came from. I dropped the motor and everything seems tight; no leaks that I can see.

Thoughts? Again, this is my first 90... zero experience w/ these motors.

Pls adv some input

thx
Jeff

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 05:39 AM  8 years agoPost 2
mchammer

rrElite Veteran

California,USA

My Posts: All  Forum  Topic

It is normal to have a substantial amount of pressure in the fuel tank with ys engines.If you have any leaky areas it will push fuel out of them.When you shut down it is good to close off the fuel line to the carb. It is possible to flood the engine after shutdown if you dont.

hope this helps.

Peace Through Superior Firepower!!!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 05:43 AM  8 years agoPost 3
mchammer

rrElite Veteran

California,USA

My Posts: All  Forum  Topic

Also, if you dont have the manual for the engine you can download one from yspartsandservice.com .It is different than other engines and it would be good to read it thoroughly to help to understand its operation. It is a simple system once you see how it works.

Peace Through Superior Firepower!!!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 05:45 AM  8 years agoPost 4
mchammer

rrElite Veteran

California,USA

My Posts: All  Forum  Topic

This is the manual for the 91sr.

http://www.yspartsandservice.com/pdf/YS91SR.pdf

Peace Through Superior Firepower!!!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 05:48 AM  8 years agoPost 5
mchammer

rrElite Veteran

California,USA

My Posts: All  Forum  Topic

And the manual for the 91st.

http://www.yspartsandservice.com/pdf/91ST.pdf

Peace Through Superior Firepower!!!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 08:16 AM  8 years agoPost 6
baby_zyklon

rrElite Veteran

Singapore

My Posts: All  Forum  Topic

Check your fuel tank for leakage.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-20-2009 03:25 PM  8 years agoPost 7
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

thx guys

the escaped nitro didnt happen the first couple tanks while rich; only after I think I leaned the HSN one click too far and was punching hard on the collective... is that pertinent?

that is to say, after those first several rich flts, when I pulled the tank pressure line to fuel I didn't notice that large escape of tank pressure

I'm running a hot Enya 3, maybe I change to a cooler OS8??

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 03:50 PM  8 years agoPost 8
PJRono

rrKey Veteran

Minnesota, Ya!

My Posts: All  Forum  Topic

No, it's normal to have up to about 10-12 PSI of pressure in the fuel system. If you leave that in the tank it will push the fuel out somewhere. I use small zip ties on all the connections to help seal them up and keep them from blowing off. I also make sure to release the pressure left in the tank after flying. My YS in my Raptor 90 blows up the tank so much that the frames actually cut into the tank. I had to make protectors to put on the side of the fuel tank to keep it from popping.

If you skip me I can't play!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 03:59 PM  8 years agoPost 9
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

Thx PJ

As mentioned, this is my 1st experience w/ crank pressure. So high tank pressure is normal; and it's increased by hard collective & punchouts?

As I'm told, these high-load maneuvers are the way the HSN is tuned. I didnt notice the pressure after hovers, while trying to tune the MSN.

Since flying a Hyper 50, I'm not used to seeing/hearing nitro drops coming from the heli after hard flts

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 04:42 PM  8 years agoPost 10
PJRono

rrKey Veteran

Minnesota, Ya!

My Posts: All  Forum  Topic

The harder you fly, the higher RPM the motor is running. More RPM = more crank pressure. The motor should run consistant through out the flight, it builds pressure almost immediately upon starting.

If you skip me I can't play!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 05:05 PM  8 years agoPost 11
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

So, unless it's gushing fuel, I shouldn't be overly concerned about several drips of nitro after landing (ie, b4 I can pull the line & release the pressure)?

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 06:00 PM  8 years agoPost 12
PJRono

rrKey Veteran

Minnesota, Ya!

My Posts: All  Forum  Topic

You should try and find where it came from. Make sure you've cable tied all the fuel line and pressure line connections. Then check to make sure the check valve is screwed tight. I used to get some leaking around the fuel tank cap if the tank was filled high enough with fuel and was pressurized. Or around the header tank cap (if you're using one).

If you skip me I can't play!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 09:12 PM  8 years agoPost 13
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

So in sum: shouldn't see any leaks/drips, regardless of how hard it's run.

I'll zip tie everything & test.

thanks

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 11:49 PM  8 years agoPost 14
mchammer

rrElite Veteran

California,USA

My Posts: All  Forum  Topic

I didnt notice the pressure after hovers, while trying to tune the MSN
It should pressureize during hovering if it is working propperly.
If it doesnt it will run lean.

Peace Through Superior Firepower!!!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-20-2009 11:55 PM  8 years agoPost 15
baddynergy

rrElite Veteran

sierra madre, ca-​usa

My Posts: All  Forum  Topic

Just make sure after EVERY flight you release tank pressure. I have found the best way is to install a t fitting between the one way and the tank. Install a short line with a plug and remove the plug after every flight. Also pull the plug when filling the tank.

see pic ofmy fuel lines for a visual.

**Unattended children will be givin a shot of espresso and a puppy**

PM  EMAIL  GALLERY  Attn:RR  Quote
03-21-2009 12:52 AM  8 years agoPost 16
baby_zyklon

rrElite Veteran

Singapore

My Posts: All  Forum  Topic

The exterior of the tank should be dry after a flight, even if you forgot to release the full pressure before chatting with your friends. Otherwise, you might be losing pressure and and fuel in flight. The exterior of the engine should be relatively dry after a flight too.

My tank used to be slightly wet around the tank stopper area after a flight and I never realised it was a leak until it got worse. After sealing the hole up properly, the exterior is dry after a 3d flight.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-21-2009 02:14 AM  8 years agoPost 17
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

yeah that's the thing... trying to pin down a leak from a microscopic hole is not unlike trying to find the cause of an electrical glitch... they're both a p.i.t.a.

I don't see any case in which fuel should appear anywhere but in the tank, at any time, in a sealed system

I tightened things up (& installed the OMI fuel mag) & will try her tomorrow

PM  EMAIL  GALLERY  Attn:RR  Quote
03-23-2009 02:13 AM  8 years agoPost 18
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

Found the culprit: the rubber grommet on the tank, that the fitting that holds the clunk goes thru, was not seating well in its hole thru the tank. I found this out using my air compressor. The leaks would occur at first pressurization, and again at pressure release- but not when nominal stable pressure was in the tank (and the leaks were not small). No freakin wonder this was driving me nutz at the field.

Remedy: switch tank holes. I put the OMI fuel mag in the outboard hole & the stopper in the middle hole, cranked the air compressor up to 25 psi 3 times, and... voila. Dry.

So it's likely I've been trying to tune w/o a sealed system. Not that it'd make much difference; since I'm still not sure where that eureka moment is when the motor's "in tune".

thx for all the replies- appreciate it

Jeff

ps- not to hijack my own thread here but my OMI fuel mag, not being weighted, floats midway in the tank. Looks wierd. Is that normal??

PM  EMAIL  GALLERY  Attn:RR  Quote
03-23-2009 03:13 AM  8 years agoPost 19
PJRono

rrKey Veteran

Minnesota, Ya!

My Posts: All  Forum  Topic

Glad you found it. It'll put your mind at ease.

If you skip me I can't play!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-23-2009 03:16 AM  8 years agoPost 20
flustercluck

rrVeteran

Newnan Ga (Just S.​of ATL)

My Posts: All  Forum  Topic

PJ on the leak front, yes.

On the "proper tuning" front... the mind's in turmoil

But at least one issue fixed

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 975 views
Scorpion Power Scorpion Power
HelicopterEngines Plugs Mufflers Fuel › 91ST Over Pressure
 Print TOPIC  Make Suggestion 

 2  Topic Subscribe

Wednesday, November 22 - 7:11 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online