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HelicopterBergen R/C Helicopters › Making nervous tail more relaxed...
05-03-2005 04:01 AM  12 years agoPost 1
gigi

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Port-au-Prince, Haiti

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Hi, guys,

I flew my Bergen on saturday, in front of a guy who hadn't seen it in a while. He remarked that the tail on it didn't seem quite as smooth as it once was...

I know for a fact that when the engine is first started, at least for the first 2-3 minutes, it kicks pretty furiously. I learned to just let it be, knowing it settles once the engine warms up. But this guy's comments got me thinking that maybe, just maybe, the needles could be better set.

I've got a G230PUM Hanson-Modified, with the W167a carb. I run 5 oz of Esso synthetic 2-stroke oil. The needles are set at 15/16 low and 1-1/4 high. Judging from the sound of the engine, it's spot-on, from idle to top-out, but the tail is indeed a tad nervous. I get some buzzing on the fin, sometimes. I do run a GV-1, set for 1,650 rpm (95% of the time) or 1,800 rpm. The gyro is a GY401, set on "normal" mode, because the servo is a JR8700G. If I set it on Digital Servo mode, it goes hard-over during intialization, and will eventually destroy the servo.

The machine flies perfectly. No gyro problems, gain set at 75% in heading-hold mode. Normally, I fly at sea-level. Twice, I flew it at 1,300 meters altitude (around 5,000 feet, I'd guess) and it does seem super-smooth up there. I did not change the needles when I went to the mountains. (As an aside, I must lean my Raptor 50v2 by a quarter turn to get it to fly there, and it also seems smoother than at sea-level.)

Does that all mean I should richen the low needle a tad, like I think? I just hate to go mess up a good thing. I learned that lesson several times before.

Thanks for any advice,

My heli spending has gone way down since I got a Honda 919 :-)

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05-03-2005 10:14 AM  12 years agoPost 2
Al Magaloff

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12,199 Posts- Enough Time Wasted. See Ya!

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When in doubt, turn the needles out. Experiment. You'll never hurt the motor going richer.

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05-03-2005 11:50 AM  12 years agoPost 3
tapeworm

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Atlanta, Ga

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Are you using Zeal tape or Foam tape to mount the gyro?

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05-03-2005 01:18 PM  12 years agoPost 4
v22chap

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Granger, Indiana

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I don't think the low idle adjustment is right ,,, I think that when I had mine it was around ,,, and suppose to be 7/8 ,,the top sounds right.This would cause the engine to kick some.... the tape might also be the problem.I would try the tape first and then go to the idle.

Larry C ----------Bergen R/C helicopters

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05-03-2005 03:28 PM  12 years agoPost 5
gigi

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Port-au-Prince, Haiti

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Quick feed-back

I am using the stock Futaba mounting tape, but underneath it, there is a small plastic platform, mounted on two strips of that expensive CSM tape, which is quite flexible. It seemed to me the shakes, if any, might come from the engine, not the gyro.

'Not much of a difference between 15/16 and 7/8... Or those needles are far too sensitive, if you ask me.

I'm not worried about ruining the engine by going richer I am worried about messing up a good setup, by trying to make it better. Haha.

I think I'll cautiously try and play with it someday I'm in the mood. Thanks for the help, guys,

Gigi

My heli spending has gone way down since I got a Honda 919 :-)

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05-03-2005 03:47 PM  12 years agoPost 6
v22chap

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Granger, Indiana

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I'm not worried about ruining the engine by going richer I am worried about messing up a good setup, by trying to make it better. Haha
been there done that ....

How old is the machine ???
I had a small vibration on a 4 yr old machine,,, that was kind of random ,,, traced it to a bad bearing in the start shaft holder. It had ground into the shaft and messed up the top of the pinion ,,,and to move the clutch ,,,it didn't move much in place ,,but after it was removed it move a quite a bit ,

Larry C ----------Bergen R/C helicopters

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05-03-2005 05:39 PM  12 years agoPost 7
Al Magaloff

rrMaster

12,199 Posts- Enough Time Wasted. See Ya!

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If my memory serves me right, before that heli was sold to GiGi, every bearing was replaced. But, knowing the guy you bought it from, anything could have gone on since I saw it last.

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05-04-2005 05:11 PM  12 years agoPost 8
gigi

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Port-au-Prince, Haiti

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I don't think it's a bearing...

I think the heli is 3-4 years old, and I don't hear any noisy bearings in it... Actually, it makes a really cool "dougoudougoudoup" sound, which I really like, and which I have not heard in any other machines. it's most noticeable in an ear-level tail-in hover. Does anyone know what part of the heli makes that sound? It's not the engine. Is it a harmonic of some sort?

(100% Off-topic) I am really into noise signatures: I can tell which heli is flying behind me if I've heard it once. A Vigor CS has a turbine-like gear whine to it. A .32 Shutle sounds completely unlike a Raptor 50v2. And my Intrepid shuts off with a "Tsch ch chhh..." from the Canfield balancer.

(back on topic) I don't think much, if anything, is wrong with the heli. Actually, if the carb is off at all, it must be really minimal. I will open the low needle a touch to see if it makes it better. But if it doesn't, I won't lean it much more than it is now, and risk shooting myself in the foot.

Regards,

Gigi

My heli spending has gone way down since I got a Honda 919 :-)

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05-04-2005 05:23 PM  12 years agoPost 9
v22chap

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Granger, Indiana

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Gigi ,, I really don't think that you have to much of a problem,, there is one more thing ,, you might be seeing the carb suck air as these seem to have a tendency to wrap a little in time from the heat and different materials put together and this will causethe needle setting to be out some ,,,but when everything warms up it will some times tighten up and be o.k. New carbs aren't that expensive ,, might try a new one if it gets worse or just bothers you to much .Mine vibrated enough that within 2 months I had went thru 2 hanson mod jugs because the muffler mounts would break off-- even runing the stock small muffler .... but it didn't vibrate that much in a hover .. but must have been in flight.

Larry C ----------Bergen R/C helicopters

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05-04-2005 11:21 PM  12 years agoPost 10
Al Magaloff

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12,199 Posts- Enough Time Wasted. See Ya!

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I think the heli is 3-4 years old
New in 1998 or 1999.

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05-05-2005 03:12 AM  12 years agoPost 11
gigi

rrVeteran

Port-au-Prince, Haiti

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The Boubou Chronicles, continued...

'Nothing quite like finding out more and more about your own model, way after you've paid too much money for it in the first place Now, it's twice as old as I was thinking... Thanks, Al! Hahaha.

Actually, V22chap, I've *just* (yesterday) received a rebuild kit from Bruce Hanson for my 167a Walbro carb. Very nice, for $7.95, it includes all the gaskets, the tiny filter, and a bunch of internal parts, plus the little priming bulb. I may or may not rebuild it soon, but at least the parts are here, if I ever decide to do so.

Gigi

My heli spending has gone way down since I got a Honda 919 :-)

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05-05-2005 03:18 AM  12 years agoPost 12
v22chap

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Granger, Indiana

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Gigi
But some times it isn't the gaskets that are the problem ,,sometimes the block warps and it won't seat on to the engine right and it lets air come inbetween the carb block and gasket and the only fix is a new carb ,,,which is usually what ,, 48.00 to 50.00 some dollars.
good luck

Larry C ----------Bergen R/C helicopters

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05-05-2005 04:58 AM  12 years agoPost 13
Malorie

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Paw squared, MI

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The phenolic block can become warped quite easily if it is overtightenned. There is really a fine line between too tight and too loose. If it does become warped, you can do as Greg said and sand it flat and reinstall it.

The symptoms, BTW, are inconsitant needle settings. If you suddenly have to start tweeking your needles, it's probably a warped phenolic block.

Malorie

Life's a journey, NOT a destination.

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05-05-2005 11:21 AM  12 years agoPost 14
v22chap

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Granger, Indiana

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Hey that RTV has a lot of usefully purposes ,,, great to hear that a quick cheap fix has been found .... thanks
Also glad to hear such a good report on the oil ,, I guess I will have to find some now that my other stuff is gone..

Larry C ----------Bergen R/C helicopters

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05-21-2005 06:11 AM  12 years agoPost 15
tpicker1

rrNovice

Memphis

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Malorie,

1. How do you know how tight to make the carb to prevent helping it to warp?

2. Is the copper high temp RTV you use the same RTV that says not to use on anything that comes in contact with gasoline?

3. Do you use white high temp loctite on the carb screws or phenolic block?

Just finished new EB the other day and everything was fine while hovering the first time a couple of days ago and trying to set needles before it got dark.

Put a new pipe (Hanson) on it (Hanson Pro 260) tonight and needles were very inconsistent and changing (Lo speed). I checked the screws and they were 1/8 to 1/4 turn loose and I had them very tight when I installed them.

4. Could I have tightened them too much? I used copper high temp RTV (the one that says not to use around gasoline) but I left the gasket between the engine case and the phenolic block there and RTV and removed the gasket on the carb side and used RTV.

The good thing is that the first time I hovered it the other day I had ZERO vibrations, no shakes on spool down, or anything. It was actually smoother than my Xspec 90. No shakes or vibrations tonight either but could'nt get it to richen up on lo speed.

Hope to actually fly it this weekend!

Thanks, ...Tim

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