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02-10-2008 08:52 PM  10 years agoPost 1
balsapro

rrVeteran

Gallatin,TN

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well if finally got my stratus up and running but i am having some vibration problems. here is my setup

OS 91 SZ cline mod
SB 18
611/9256 gyro with stepdown
9155 x 3
multigov
duralite reg and bat running 6 volt

so here is the problem everything is smooth until takeoff. a storm develops in the main tank and it starts to foam and continues much more at high rpm. I'm running the Maryland machine fan and the runnout was .002 if i remember correctly. Althought i know its high freq vibs could this just be due to a new engine breaking in??

I did the alignment adjustment to the motor in hover and this helped but did not cure the foam problem.

secondly the 611 its not really drifting, I would describe it as more of a hunting. I lowered the gain and no difference so i returned it back to where i had it previously.(611 display reads 36) it does not do it all the time. it acts good when the main tank is about half full, i reckon it may be due to the motor tunning but as it is it not sloppy rich.

one interesting thing i did notice is that there was not much back pressure from the OS 91 SZ and it acted like it was going lean at the end of the tank. on all my other helis,also setup with OS 91 SZ with cline after a good run you can relase the pressure and hear a psssss. so i think my tank may be leaking but i do not see or hear anything excessive.

any ideas.

Build the Best, Fly the Best, Crash the Best

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02-10-2008 10:20 PM  10 years agoPost 2
Dave Yost

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San Diego Ca, USA

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Sounds like it is going lean. I would change all the fuel line.

I would also check to make sure the carb in seated in the case all the way, and that o ring is not cracked.

Just a thought.

Dave

MA Fury Extreme,Vibe 50, JR 9303,YS,Vblades, Don't blame me, I voted for Jimmy Buffet!

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02-11-2008 02:35 PM  10 years agoPost 3
bparro

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indianapolis,in

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Also make sure your check valve is not backwards.

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02-11-2008 05:05 PM  10 years agoPost 4
balsapro

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Gallatin,TN

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I checked the check valve everything is working properly there.

ran abut 5 tanks through it yesterday hoping things would smooth out, it didn't.

right now i have it disassembled and am going to recheck things.

Build the Best, Fly the Best, Crash the Best

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02-11-2008 05:56 PM  10 years agoPost 5
QuickSilver

rrVeteran

Cherry Hill, New Jersey

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Foam
Replace the check valve anyways, yes it may hold pressure but are you sure its holding the 2 lbs that it's supposed to? Just for piece of mind I would take the check valve off of one of your machines that is running good and put it on the Stratus. I have seen that foam issue before on the Synergy, but not on a Stratus and every Synergy I saw this happening in had the SZ motor. The only thing that would cause that foam IMHO is air being sucked in to the fuel tank and or vibration. Where its being sucked in is another story, and depending on which SZ you have I do know they had vibration issues before they came out with the balanced crankshaft. Hope this helps.

Take care,

Kyle

Stanley Bostitch
Proto Tools

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02-11-2008 06:14 PM  10 years agoPost 6
Daves

rrApprentice

Tallahassee, Florida

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Sounds as if you may have several things going on at once.

Certainly, a motor that isn't properly tuned can result in a vibration problem, but that is usually a tail "kick" as the motor aggravates the gyro.

I'm not familiar with the Maryland fan, but I can tell you that you must start with a fan that has been properly balanced. Then, to get a smooth run, the fan really needs to be dialed down to .001 or less. You can get away with .002, but you'll be lucky if you don't have a shake and foaming fuel.

Yeah, I know that's a real pain, but it is doable. I've spent as long as 4 hours just dialing the fan, but I can usually get below .001 within 30 minutes or even sooner if I get lucky.

One technique that many of us use is to take a dremel and cut a slot in the lower collet. You should also add a very light coat of thin oil on both upper and lower collet. That will allow the collet to seat and make the dialing process much easier.

Motor alignment is also critical as is the spacing between the fan hub and clutch. The spacing should be about .010 and you should check the spacing/alignment both left & right as well as front & back.

Hope this helps. I can tell you that the extra effort at balancing and dialing the fan will be well worth the work in the long run.

Dave

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02-11-2008 07:09 PM  10 years agoPost 7
Dr.Ben

rrMaster

Richmond, VA, USA

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If the best TIR on that Md fan was .002", then you need to get on the phone with them and let them tell you how to tweak it down to 0.001" or better. 2 thou ain't gonna cut it. Get the fan correct before you go nuts chnasing other potential vibration sources.

If you don't have the frame stiffeners installed, do so without fail.

Ben Minor

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02-11-2008 07:26 PM  10 years agoPost 8
Funky Trex

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Westerville, OH - USA

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How did you align the motor when installing it? I am not sure if it makes a difference, but before tightening the 4 bolts holding my motor plate to the bottom plate, I spun the start shaft with my starter. I was told this would help align the motor. I was very careful not to move/flex anything and finished snugging the bolts to secure the motor plate to the bottom plate.

I am on my 3rd 91SZ in my Stratus and with some help from a friend we were able to get down to less than .001 runout on all 3 motors (2 different fans and 3 different sets of collets). None of them have foamed the tank and I haven't had vibe issues with any of them.

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02-11-2008 07:34 PM  10 years agoPost 9
rstacy

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Rochester, NY

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one interesting thing i did notice is that there was not much back pressure from the OS 91 SZ and it acted like it was going lean at the end of the tank. on all my other helis,also setup with OS 91 SZ with cline after a good run you can relase the pressure and hear a psssss. so i think my tank may be leaking but i do not see or hear anything excessive.
I think you are right on the tank leaking. There should be a noticeable amount of pressure in the tank at the end of the flight. You must fix this. Pull the tank and do the under water pressure test. At times I forget to release the pressure on our tank and find that it holds that pressure until I fuel it up for the next flight. It wizzes all over the place when I pull the pick up line for fueling.

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02-11-2008 09:29 PM  10 years agoPost 10
QuickSilver

rrVeteran

Cherry Hill, New Jersey

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Pressure in the tank
Forgetting to release the pressure too many times can also damage your regulator from what I've been told.

Kyle

Stanley Bostitch
Proto Tools

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02-11-2008 09:59 PM  10 years agoPost 11
rstacy

rrElite Veteran

Rochester, NY

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Forgetting to release the pressure too many times can also damage your regulator from what I've been told.
That wouldnt surprise me.

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02-12-2008 12:49 AM  10 years agoPost 12
airdodger

rrElite Veteran

Johnston USA

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Here is a post about the fan, have not tried the ways to get the fan perfect, if you do please post how successful you were. My fan dialed under a thou. [quote] Hello Guys,

I would just like to say thanks this is the 1st time reading any feedback!

I use heat gun on center of hub only it takes about 30 seconds to expand the bore and the magnets do not even see the heat I have even but the fan under hot water and it also works fine!

You can even use small Butane torch at the field !

Use no heat to remove just the MA fan puller it works fine And if your fan if ever damaged simlply email me and I will make arrangments to replace!!

As for adjustments to a fan that has runout of .001 There are simple ways to get it perfect!

As for Balancing I would never drill holes in it I would file a small flat on the outside diameter of the fan if needed most of the time it is not! But depending on magnets weight you may want to make perfect!None of mine are balanced It is So small of an amount I never noticed a difference!

Lets make sure You have everything right before you do this !

Only check the C-Bore where the Delrin ball gets inserted This is the only critical spot that many Pilots Want perfect!everthing else will follow perfectly as it is all turned and bore at one setup!

Do not use A plunge indicater (false readings occur.)!
Check runout before and after installation of the nut, As most of the time people are making the fan to tight and defleting the fan!

1. Make sure you use a thick precision ground washer .125 at least the thinner washers let the face of the nut which is not perfetly perpindicual to the crank deflect the fan !!( I am looking into suppling these also)

2. If you have the 1st issue resolved and still .001 runout I use a center punch to Dimple the underside of washer then record on fan which way you need to influence the fan and place dimple to that spot(even a small piece of plastic shim can do the job nicely.)

Thanks For all the support Guys
Brent Long
Maryland Machine

Chris

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02-12-2008 02:04 AM  10 years agoPost 13
balsapro

rrVeteran

Gallatin,TN

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update
I rechecked the runout on the fan and like i said above it was at .002

I have now got it down to below .001. i don't know the exact measurement my dial indicator only goes to the nearest thousandth but I figure it is something like .0005 to .00075 but it is less than .001.
I might slave over it and try the center punch idea to get it closer. I would like it to be 0 but i want to be realistic.

I also checked the balance of the fan the best I could and it seemed alright if it is out of balance it is very minimal.

couple of interesting things I noticed. I dial indicated the crank shaft it was out .001 just before the threads. Here is the wired thing, I think I was getting an inconstant read due to the threads but the end of the shaft was out something like .004-.006 out.

anyway what is the normal runout on the crankshaft.

as soon as i get this right its on to sealing the tank better. i read MA's instructions a long time ago but was wondering what type of sealant to use is there anything better than RTV

Build the Best, Fly the Best, Crash the Best

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02-12-2008 02:50 AM  10 years agoPost 14
airdodger

rrElite Veteran

Johnston USA

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On the tank caps I use teflon tape, I pressure test for nine pounds no leaks yet.

Chris

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02-12-2008 03:35 AM  10 years agoPost 15
BJames111

rrElite Veteran

San Diego, California

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It wizzes all over the place when I pull the pick up line for fueling
ahhhh yes, the YS shower...very familiar.

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