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Engine basics => Engine set up tips => Topic started by: Robin_Holden on April 03, 2009, 01:26:22 AM

Title: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: Robin_Holden on April 03, 2009, 01:26:22 AM
Greetings guys from a mild and sunny Charente in S.W.France.

Went to the field yesterday , late afternoon, no wind ....paradise. Took my ' mod'd Twister ' which has an OS35 FP beautifully modified by Tom Dixon. I was using a plastic tank , plumbed for uniflow and fuel with 24% lube' and my usual flying prop' , a Master 10x6.
The FP started as usual , and settled down to it's normal flying setting.

So , first flight , all just fine as usual. Came down without a hitch [ which is a big bonus for me ! ] and let her cool off while my pal and I sorted out the world's financial crisis !

Next run ....Odd ... started her up 2nd or 3rd flick [ all Tom's engines start on the button ] but I had to wind the needle in almost half a turn to get the same revs on the tach' , just on the 4/2 break.

Now I'm a re-tread , only coming back to C/L Stunt a few years back after a long working 'sabbatical' so I would appreciate any of your views.

Probably I'm missing the blatantly obvious , so if I am ....apologies.

Once again , thanks and a great forum fellas.

Kind regards from an ex-pat retired Brit in the Charente - full of ex-pat retired Brits !

Robin.
Title: Re: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: james dean on April 03, 2009, 03:27:55 AM
Hello Robin,   Your problem really is just atmospheric in regards to the needle setting.  Most likely your engine was not the only thing cooling off after you landed.  The airtemp. may very well  have gone down a degree or two and there may have been a rise in the humidity along with the drop on air temp..

 Happens often as the day cools into the afternoon during those weighty talks of world financial issues!  HB~> LL~ %^@

This a common thing as the day cools off or a weather change is approaching the flying area.   ;) H^^ H^^

Hope this helps,

James Dean
Title: Re: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: Robin_Holden on April 03, 2009, 08:29:02 AM
James , very much obliged for your comments. Like I said ,the answer is pretty obvious , but not to me sadly !!

Regards ,

Robin.
Title: Re: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: Busby on April 03, 2009, 09:44:43 AM
It could have also been something as getting the old castor flushed out of the needle.
Busby
Title: Re: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: Steve Helmick on April 03, 2009, 09:23:17 PM
Or chunks of old truffles flushed through?  LL~ Steve
Title: Re: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: Robin_Holden on April 04, 2009, 09:24:52 AM
Steve ....We don't know anybody who can afford truffles !!

If there's any around I'll let you know ,

Regards ,

Robin
Title: Re: O.S 35 FP : NEEDLE SETTING ALTERS ?
Post by: Ralph Wenzel (d) on April 04, 2009, 10:02:02 AM
I can offer one more possibility, Robin. I once had the solder on the needle to the ratchet break, so the knob spun without moving the needle. I know you said the needle eventually screwed in enough, but it's something to check . . .