rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 419 ONLINE 46 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]1205 viewsPOST REPLY
Advantage Hobby . Revolution Models . CarbonXtreme

.
.
Blitz Helicopters Avro 90 > Flight of my AVRO on Sunday - video -
 
 
AreA51tje
Senior Heliman
Location: Murcia, Spain

Hi Guys,
Just wanted to share a small video of my flight sunday afternoon! Had an engine stop due to a failure in Header tank but that problem is solved (had a leak in the Quick Uk exit tube).

Needed to autorotate from an inverted position near to the ground, must say that it was incredible because the heli kept the blades spinning and spinning.

The Engine which is a YS91ST is running at 70% of his power at the moment.

Enjoy!

http://www.youtube.com/watch?v=mP3r-rrHtfI



PROBLEM PLEASE HELP

So now I do have a small problem, let me try to explain:

After the stop I didnt start the engine again and went home, the day after I wanted to fly it again and noticed problems getting it started (offcourse after i changed the header tank).

I needed to put gas at 50% before it even started, so i thoughed maybe the glowplug is broken. changed it (use the enya 3) and same problem. Any way it started and at full throthle the rotor was spinning with very low rpm, not even enough to get it off the ground. Then I stoped it checked it and started again and could really hold the rotor with full throtlle.

Needles more or less 1 3/4 opened high and mid needle.

I fly with fuel mix of 30% nitro and 23-25% Klotz 198

Any body have an idea of what it could be?

Regards, Dave


04-03-2008 01:13 PM
HOMEPAGE  
 
 
RyanW
Veteran
Location: Stillwater, Oklahoma

Remove your throttle linkage and check to see that the arm on the throttle barrel hasn't rotated. It sounds like that could be the culprit.

-Ryan
04-03-2008 03:01 PM
HOMEPAGE  
 
 
RyanW
Veteran
Location: Stillwater, Oklahoma

I just re-read your post and if you have 1 3/4 open on both high and mid, that could be a problem as well. For the ST4, I had the high end between 3/4 and 1 turn open and the mid always sat around 1 1/2 turns open.
04-03-2008 03:06 PM
HOMEPAGE  
 
 
The Old Guy
Senior Heliman
Location: UK Surrey

It is unlikely But that sounds like a cooked piston!!!!!!!!!!!!
04-03-2008 08:04 PM
HOMEPAGE  
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

Sorry to side track....but,

OMG has that field got nice grass!! Better than most golf greens!

As for the engine, if those needle settings are accurate, I doubth the piston is cooked. That is, unless the "header tank problem" resulted in a very lean run. The piston may actually have a small burn through and still the engine could run at high throttle settings, albeit with no power.

I'm still in awe over that lawn...
04-03-2008 10:24 PM
 
 
AreA51tje
Senior Heliman
Location: Murcia, Spain

Erich, thats my private flying field. its a 350 meter long driving range on our golf course (www.thekey.es).
Anyway...

Talked with Neal for a long time and all his pilots told him directly a problem with the engine and thats not a fuel flow problem.

The engine is still quite new therefor I have the needles a little more open to garanty a good break in. temperature is around 80-85 degrees celcius. Ryan, which temperature had your engine? The engine was going very well with this setup. you noticed in the 4p tic toc that it didnt hold well but that was as well because I have my engine running at 70% max of his power.

Going to dismount the engine this evening to see if it has a problem. Will post pictures this evening of the engine.

Ryan, the throttle linkage works fine no problem there.

Regards, Dave
04-04-2008 06:32 PM
HOMEPAGE  
 
 
e-copter
Senior Heliman
Location: Nice, France

Hi,

you should maybe check the whole fule line tubes, as well as the pressurisation tube, if your engine does not start with less than 50% of fuel fill in the main tank, it could mean that it needs the fuel to be at the header tank level to spread direct to the carb input, so that there is no help or difficulties to run across the pipes.

Eventually, check that there is nothing in the carb itself, and i would double check the fuel connector / remove needle to clean up the place after checking everything else.

As you did unmount maybe your header tank, make sure that when putting back the exit tube that one is perfect and has noghing inside preventing the fuel to run.

Normally, the leak in the exit tube only made your engine cut as we sometimes do when we crash our helis and have no more possibility to cut the motor with the transmitter ( pinchig the fuel intake tube). I doubt this would have burned your engine as it only happens when you run long times and high rev with a too leak mixture. if you cut fuel, motor.. cuts

Anyway, just hope nothing weird, and that the Avro will be back in the air as soon as possible

BEst regards,

Fabien

Too much is not enough....
04-05-2008 01:01 AM
 
 
AreA51tje
Senior Heliman
Location: Murcia, Spain

Hi Guys,
Thanks for all the answers, but think I have found the cause of the problem

I dismounted the engine and openend it, and there you see that the piston is damaged. Dont know why but looks like that something was in the cilinder which was hitting the piston over and over.

What is your opinion?

Here go two pictures,
Regards, Dave

04-05-2008 09:12 PM
HOMEPAGE  
 
 
ErichF
Key Veteran
Location: Odessa, FL 33556 (Tampa Area)

Pull the piston and see if the wrist pin retaining clips are missing. Sometimes those can pop loose and bounce around in the engine.
04-05-2008 09:19 PM
 
 
The Old Guy
Senior Heliman
Location: UK Surrey

Looks like the back bearing cage has broken up
That is tough
I lost an OS 90sz recently like that
04-05-2008 10:59 PM
HOMEPAGE  
 
 
e-copter
Senior Heliman
Location: Nice, France

Ouch !!!

Well may be time for me in thinking about ceramic bearings..
Anybody tried these in our engines ?

BEst regards,

Fabien

Too much is not enough....
04-06-2008 12:08 AM
 
 
AreA51tje
Senior Heliman
Location: Murcia, Spain

I will send my engine back to Neal on Monday, he will repair it and check it. If I know the exact cause what happend I will inform you guys..

What is advantage of these ceramic bearings?
Regards,
Dave
04-06-2008 01:16 PM
HOMEPAGE  
 
 
stanc
Veteran
Location: Conroe, TX

Ceramic bearings last longer but the cost is a lot higher. I have read here on RR, that they can crush in a crash. I have one in a Hacker electric motor, its never been in a crash so can testify to what will happen.
Go to Boca Bearing, fine the size of your bearings and see what they cost.

Stan

Stan
2 x Ion X2
eStartus
eAvro90
Performance Plus Lipo Packs
04-06-2008 01:50 PM
 
 
MattJen
Elite Veteran
Location: UK,Gravesend, Kent

the only thing i ever heard against ceramics - and this is nothing i have proved myself..

is if you get say a tiny piece of filing in the engine the ceramic could shatter cos it is harder, where as the normal bearing is softer and will allow the filing to press into the ball..

Again i have never proved it, so it maybe true it may not,which is why i have a full set of ceramics for the YS engine... i have never put them in..


Matt

I bought mymother in law a chair for xmas, but she would not plug it in.
04-06-2008 02:25 PM
 
 
e-copter
Senior Heliman
Location: Nice, France

Hi,

thanks for the reply, well i think i'll go for a ceramic set and see how it goes, before converting to electric with the new Scorpion motor ))
BEst regards,
Fabien

Too much is not enough....
04-07-2008 11:49 PM
 
 
alfred
Senior Heliman
Location: Australia, New South Wales, Mid North Coast

Must be just me, but this engine looks like it's run waay too lean.
An engine with such little runtime should have an absolute clean piston crown with no apparent burned oil.
It should have been a shiny alloy silver colour with apparent oil sitting on the top.

I am sure that you had your needles set to a rich run-in stage.
Maybe you lost pressure in the tank due to the check-valve having stuck close for a short while?
Maybe swerve in the carby?
04-08-2008 10:14 AM
 
 
Droid
Elite Veteran
Location: Deep down in the Southwest- UK

I wouldn't run the ceramics unless you want your engine to grenade itself. When they let go they shatter and pepper the internals of your engine, nothing is salvageable. ( Bitter experience )

Why are you running at 70% power????

That piston looks like its had a lean run and started detonating. Is the shim present??

Quotes may have been changed for my own amusement
04-08-2008 06:40 PM
 
 
e-copter
Senior Heliman
Location: Nice, France

Hi,

thanks for the update, so well i'll go for regular bearings then and i'll keep rich setting ))

BEst regards,

Fabien

Too much is not enough....
04-08-2008 06:42 PM
 
 
AreA51tje
Senior Heliman
Location: Murcia, Spain

Hi Guys, just have been talking to Blitz because he received my engine today and after inspection of my engine. There is no doubt that the big end bearing has failed.

Will inform you guys a little more when I have more informations...
Regards, Dave
04-10-2008 12:03 AM
HOMEPAGE  
 
 
RyanW
Veteran
Location: Stillwater, Oklahoma

One nice thing about the new YS SR is the rear bearing has been improved. It has a ball race that looks to be some type of polymer. It shouldn't corrode or break down. Unfortunately I don't think they are interchangeable between the ST and SR.

-Ryan
04-10-2008 02:59 AM
HOMEPAGE  
 
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]1205 viewsPOST REPLY
Midland Helicopters . HeliProz . ZoomsHobbies

.
.
Blitz Helicopters Avro 90 > Flight of my AVRO on Sunday - video -
  UPDATE SCREEN   PRINT TOPIC Advertisers 

Subscribe to This Topic

Saturday, August 30 - 6:48 am - Copyright © 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie