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Bell 47 Crash

Old 07-08-2010, 01:04 AM
  #51  
yacsf
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Default RE: Bell 47 Crash


ORIGINAL: lawrencelkl

Hi all,

some updates from me. the engine did not get to idle well and only run when the choke was partially opened, will die out immediately when choke fully open. Engine was stuggling to lift at all, and seems very hot.
as suggested by Glenn, i cleaned the carby and all changed. this is the video taken after the carby is cleanned.

Thanks a lot folks!

http://www.youtube.com/watch?v=q9MZr6MS4gg


Lawrence
Hi Lawrence,

Beside replacing the caskets for the carb. You need to check the engine compression. Check your piston and piston rings which cause the choke cannot fully open to run the engine smoothly.
Old 07-08-2010, 02:09 AM
  #52  
lawrencelkl
 
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Default RE: Bell 47 Crash

Hi yacsf,

thanks for your input. how do we check compression of the piston? is it just normal 'feel' when we pull the cord or is there a more technical way to check it?

thanks.

Lawrence
Old 07-08-2010, 02:41 AM
  #53  
glenladen
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Default RE: Bell 47 Crash

G'day Lawrence,
If you can pull the starter cord with very little resistance then your engines down on compression,on the other hand if you pull the starter cord and it requires abit of effort on your part then engine compression isn't a problem.
How has the flying been with her?.
cheers,
glenn.
Old 07-08-2010, 02:54 AM
  #54  
lawrencelkl
 
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Default RE: Bell 47 Crash

G'day Glenn,

Thanks for the fast response, in that sense I think the compression is still pretty good as I find it quite an effort to pull the cord! some muscle training..

I have been busy for a moving recently and also just came back from a trip to Italy not long ago hence have not been flying with her much.

I need to find some place near my new place where Icna fly her. How about yours?

Cheers.

Lawrence
Old 07-09-2010, 12:55 AM
  #55  
yacsf
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Default RE: Bell 47 Crash

Hi Lawrence,

I did dismantle the engine and remove the piston block to physically see the piston and rings condition, cos when I tested by pulling the cord. I don't feel any difference. Until open and see that the piston rings stuck onto the piston. There is no play. After changing both piston rings. It was so easy to start.

Old 07-09-2010, 01:12 AM
  #56  
glenladen
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Default RE: Bell 47 Crash

G'day Lawrence and Claude,good point Claude could have gunge all over the piston and rings.
I been on courses and haven't had much of a chance at flying her after fitting the dummy tanks,looks as tho' the carby will require tuning and the after market filter I had fitted interfeered with the mixture needles.
So I've refitted the original filter so I can use the choke.
cheers,
Glenn.
Old 07-06-2011, 01:40 AM
  #57  
lawrencelkl
 
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Default RE: Bell 47 Crash

Hey folks,

flawn my old bell 47 G again last weekend ( jsut heli body, no canopy or seats etc yet) and it was hoverring good! then after a while, i started to get crazy glitches again whenever i throttle up! it was pretty scary considering its size and torque. looked for metal contacts, antena length etc but still cannot eliminate it. I am currently on 35Mhz and not sure if 2.4 will help here? any idea?

also, pardon me to ask some really basic questions. I read some posts and saying that the butterfly valve is VERY different from nitro's carb. My question is: if i am settign throttle servo linkage such that it is fully closed and fully opened at 0% and 100% (i.e. 0 degree fully closed, 90 degree fully opened), what (range) of throttle curve should i be looking at?

what i am seeing now is i can hover around mid stick, but once i increased that futher up, it is not gaining power and actually loosing power.

My both Throttle and pitch curve is not fat from the linear 0, 25, 50, 75, 100 at the moment and i think the throttle curve is way too high?

many thanks !

Lawrence

Please kindly let me know what curves are you guy using and waht is the maximum opening of the batterfly valve should i use?
Old 07-15-2011, 04:22 AM
  #58  
glenladen
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Default RE: Bell 47 Crash

G'day Lawrence,good to hear from you,I've only just got back from an unplanned trip.Okay if you've checked for the usual suspects and found nothing,then have a look at the plug lead for any damage or the plug itself for any cracks in it,also your Rx battery leads to the switch and rx for any damage caused through rubbing.If they are ok,do an inspection on your crystal as it might be cracked or it may have come loose.
I have my butterfly valve setup so that it's fully open at full throttleI will chase up my throttle/Pitch setting's for you as they are not to hand at the moment.
Are your collective pitch servo and throttle servo matched for the same speed as if the CP servo is faster the the throt servo you will have head snatching and it will give the impression that the throttle/pitch setting's are outit's the same with the throt servo being faster than the pitch servo you end up with the engine bogging down when throttling up due to the pitch servo not keeping up with the throt servo.

cheers,
glenn.
Old 03-01-2012, 06:15 AM
  #59  
lawrencelkl
 
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Default RE: Bell 47 Crash

Hey guys!


back with some updates for my bell 47G. flown ok (as video) Jan 2012 in UK during cold weather.
Hitec 2.4 GHz radio ( no interference), nhp razor pro 800 mm symmetrical blades.

brough the heli back to Malaysia then mayeb the hot weather make the heli struggling to climb, can slightly lift off and that's it.
the tail strut got broken parts so need to repair that before testign again.. was playing with pitch curve, engine setting etc. but now i am back to UK meaning have to wait till my next visit home in Malaysia..

anyway, the video link is

http://www.youtube.com/watch?v=PWlZUi0Q6hM

and some pics...
Old 03-01-2012, 06:26 AM
  #60  
lawrencelkl
 
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Default RE: Bell 47 Crash

some photos...
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