G23 piston weight.

[sorensen]

Hi.

Can anyone tell me how much does a zenoah G23 piston weigh?
What does the piston/pin/rod assembly weigh?

I need to balance my G26 or use my Bergen Observer as a BIG paper weight. :arggg:

Thanks!

[cbergen]

If it's that bad, a trip to Hanson may be in order.

However, we have been using stock G26's in the Observer's, what is necessary is tuning and loading the engine and rotor system properly to achieve a smooth running engine.

Have you checked out Gary's Tuning Video? http://www.garytravisrc.com/id2.html

http://youtube.com/watch?v=F6TdeP5fXKs This is from a stock engine also.

What is your oil ratio and needle settings?

[Gary Travis]

I Am running all stock g26 engines in several Bergens, if you are seeing vibes in the video chech the set up and mixtures. It has been my experience the these are the most likely cause. If you have a video clip just e-mail it to me and I'll try to pinpoint it for you.

Here's another shot with a stock G26

http://www.youtube.com/watch?v=MOSuM8NnU04

Gary

[rbort]

I hate to contradict Gary here on this subject, but what makes you believe that if you have an out of balance engine you can fix it by adjusting mixture and loading it down?

We all know that the balance of the G26 motor is not right as Zenoah used a different top end with the same bottom end. To properly fix that, you need to lighten the piston as Hanson would do.

However, this is not to say that adjusting mixtures doesn't help. Sure it does. But adjusting a balanced motor mixture helps even more.

The Bergen machines may be more tolerable to vibrations due to its G10 frames and motor mount points, but it doesn't mean its not shaking. I think what you want to say Gary is that you can get a stock motor to work if you do the above you stated, but you will always end up with better results if you take the extra step to balance the motor.

-=>Raja.

[Gary Travis]

Raja, What I was trying to say was that most of the ones I have seen were in fact tunning issues rather than mechanical issues, I have once or twice seen a badly balanced engine but not often.
Gary

[sorensen]

Hi.

I bought the Observer in 2003.
This was my first and only gasoline engine experience.
A lot different than a nitro engine.
But I THINK I have gotten the hang of tuning it.

I'm using 95 octane unleaded gasoline and Shell Racingway 2 stroke synthetic oil.

I did run the engine in at 6oz oil per gallon.
After that I used 5oz per gallon except last summer I tried a couple of tanks with 4oz per gallon.
The engine sounded maybe a little bit smoother with 4oz oil per gallon.

It is running pretty smooth with 5oz per gallon oil going by sound.

But it still produces a lot of hi frequent vibrations.
Fan run out is 0.002", I can't get it any better.

Chris: do you have fans with collets like MA helis?

I have not checked the crankshaft run out but I will pull the engine out and take a look in a couple of days.
I will also look at the internals to see what amount of material it's possible to remove from the piston.
Or maybe I will try putting a Tungsten slug in the crankshafts counterweight to help counterbalance the G26 piston.

I really want this Observer to fly.
I have also seriously considered to do the EB upgrade to help flying performance and auto performance.
With all the camera gear, gyros and video downlink it really is too heavy compared to the rotorarea to fly any good.
BTW: This is MY opinion, others may disagree!
And Autorotations.. I have done atleast 50-60 autos with it but it's freaking scary everytime.
It's not that I don't like the adrenaline rush :) but I don't like the thought of smashing all that expensive equipment.
So I was hoping an EB upgrade would make it more relaxing and more steady to fly plus safer to autorotate.

But I feel that I have used too much money on it already.
I also have to buy some new spare parts, because of the vibrations the bearings in the collective arms have eaten the bearingholes bigger.
There may be other things too, but I just gave it all up last summer.

But now I have done some successful crankshaft modifications and balancing stuff on my nitro engines.
Therefore I was thinking about giving the Observer another shot by trying to balance the G26 engine.

PS: I'm trying to explain the best I can but English is not my native language.

[rbort]

Why don't you take the easy route and send the engine to Hanson to balance it for you? You really need to true the crank (2 thousands is too much), balance the rotor, and reduce the weight of the piston. While you can try to do it yourself for around $150 you can bolt and go and never look back.

Just a suggestion to make your life easier. Sometimes you can get more frustrated trying to reinvent the wheel than to just let someone else repeat their invention for the 500th time.

-=>Raja.

[cbergen]

Too many things to answer in one post!!!

Sorenson, Your English is excellent.

As I wrote previously, In these machines (Observers) which unfortunately Raja has zero experience, Gary has LOADS, the vast majority of vibration problems comes down to loading the engine and head properly. Not ONLY tuning the engine, but also tuning the helicopter. Gay's Tuning DVD explains this VERY well.

I do agree that sending the engine to Hanson (Al) would be better than (timewise and frustration wise) experimenting with it yourself. Yes there are some engines worse than others, and it is very possible that yours is an exceptionally bad one, in which case a balancing job would be best.

If the fan runout is .002, that is perfectly acceptable, the bearings in the engine (especially an older one) can allow this much!! Don't believe it? When you dial indicate, push sideways on the fan hub.... The tapered crank shaft of the engine does not allow the tapered collets that you speak of, even MA does NOT use them on the gasser engines.

What headspeed have you been running?

The EB upgrade does allow the use of bigger blades, obviously turning at a slower RPM, and does add to the auto performance. I also think it's a bit easier to tune the heli (loading the engine and rotor system) with the bigger blades.

We're here to help. We, and especially Gary, have a lot of experience with setup on this particular heli, rather than a generic understanding of gassers.

[rbort]

Sorry Chris, not trying to offend anyone here or seem "generic" as you say, but the whole point I was trying to make is that a balanced engine will be better than a stock one, even in an Observer and I don't need any experience with any specific heli to say that. :)

Now this I've seen and have been told. Zenoah engines come out of the factory with as much as 2 thousands off (bend) on the crankshaft and that is "within tolerance". Some motors are better than others. When you send your motor to Hanson and he trues your crank, it will be within 1/2 thousands. Now that's an improvement I can't pass up. Not to mention he will balance the rotor -- I've never seen one of those perfect stock on a high point, and lastly and most importantly he will put in a lighter piston which will reduce the vibrations and shake the machine less.

Yes Chris you are probably absolutely right you can make a stock motor work in your machine and some are better than others. But you can't deny that a balanced motor in one of your machines will make the machine even smoother and everything else will last longer on it. There is no required experience (zero is sufficient) to make this statement.

You know what, I just reread my post and I don't want to make anyone here feel that they have to do what I suggest, its only that, a suggestion. Some people balance blades, some people fly them out of the box as is. Some people balance fans, some people don't. I like to balance blades, fans, center flybars, check weight of paddles, and send my engines to Hanson to give my machine the best possible ride and the least amount of vibrations. That is just me and maybe I'm too anal. Sorry if I sounded that way, its not meant to be "I'm Mr. right" so please do what you wish and if my advice helps then great.

Peace!

-=>Raja.

[cbergen]

When I read this,
but what makes you believe that if you have an out of balance engine you can fix it by adjusting mixture and loading it down?

And you say this,
We all know that the balance of the G26 motor is not right as Zenoah used a different top end with the same bottom end.

I read this as you basically calling Gary, and us, a liar.

When we say,
the vast majority of vibration problems comes down to loading the engine and head properly. Not ONLY tuning the engine, but also tuning the helicopter.

Try rereading what I AND Gary wrote, Wait I'll Quote it for you,
If it's that bad, a trip to Hanson may be in order.
I do agree that sending the engine to Hanson (Al) would be better than (timewise and frustration wise) experimenting with it yourself. Yes there are some engines worse than others, and it is very possible that yours is an exceptionally bad one, in which case a balancing job would be best.
I have once or twice seen a badly balanced engine but not often.


IF the engine is a terribly balanced one, then yes, a trip to hanson would be best, I already said that. BUT and a BIG BUT, most of the time it's a simple matter of tuning.

How about spending $24.00 vs $175 or whatever Hanson charges to find out??

[rbort]

Chris:

You need to read the whole message (and the explanatory message following) as a whole and not just quote a line here and there and misunderstand the context. You quoted my first and 2nd line in my original post. Why didn't you quote my 3rd and 4th lines out of my email, maybe because they didn't support you point?

I made a simple statement that a balanced motor is better than one that isn't but somehow it was misinterpreted. This isn't about a war on who replies best and sticks it to the next guy he doesn't agree with, its about sharing information and giving opinions. My opinion should not offend you or Gary and make you nasty to me and say I'm calling you guys "liars."

Anyway Sorensen, do what Chris says -- buy Gary's video and see if you can tune your engine as that may be enough for you to get your heli going.

-=>Raja.

[cbergen]

Raja,

Your point is that ALL G26's are out of balance, therefore, NONE of them can be made to run without vibrations in the heli.

Therefore, we must be lying.... but all you have to do is look at the video. Or is that fake too??

I certainly agree a balanced motor is better, but NOT necessary!! Of course someone may not realize that until AFTER they have spent a good wad of cash, and then find out, well this thing is a POS, IT STILL SHAKES!! And why does it still shake? Because the heli STILL isn't tuned properly!!

In YOUR heli, this may be totally absolutely necessary. If I were to fly YOUR heli, I would certainly follow YOUR recommendations.

Your opinion doesn't offend, you are certainly welcome to it, only the fact that it is inaccurate, is why I refute it.

[MarkWebber]

I have witnessed exactly what Chris is describing in my own EB. Following my build and tuning to the best of my abilities, I still had a bit of vibration. Nothing sever mind you, but enough that I was about to ship the engine off to Hanson as many suggest. Fortunately, I caught up with Chris at a funfly and watched as he tuned my curves (as well as another Bergen customer's) for vibe free flight. As in, there wasn't a twitch in it! Antenna, starter handle, tail..nothing. Therefore, I must believe him. Get your setup right and you still have engine vibes then maybe that rare 'problem' engine made it to you.