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Engine basics => Engine set up tips => Topic started by: John Park on July 22, 2021, 06:31:40 AM

Title: OS .15 LA-S Question
Post by: John Park on July 22, 2021, 06:31:40 AM

Wanting to fly some of my old .15-powered models, I've just got hold of an OS .15 LA-S.  Question: does anyone know whether the .15 FP backplate is compatible with the .15 LA?  If it is, I'll see if I can find one.  If not, I'll reluctantly attack the LA's plastic backplate to remove the bulky, inconvenient remote NVA - I have a standard NVA from an old .15-III that I'd rather use, as it'll save me having to make ugly modifications to the models (I've already got to widen the spacing of the mounting bolts by 2mm.).

All advice gratefully received.

John

Title: Re: OS .15 LA-S Question
Post by: Dwayne Donnelly on July 22, 2021, 08:39:47 AM

I did this, removed the excess plastic added a OS 15 needle and couldn't be happier. Works great.  y1

Title: Re: OS .15 LA-S Question
Post by: Air Ministry . on July 22, 2021, 11:23:13 PM

Chewed the extension off a LA 46 . Used a saw actually. then a file . Then a stick with say 120 wet & dry . Hard to pick its been done . Tighten ? the screws even till no slack , then just a iota nip . Dont TIGHTEN them
HARD . Ya seea lotta backplates with the corners chewed off. the black nylon ones , You Do Not want to distort them . Just a smidgen tight each even , after theyre snugged down even . Its unstressed if done right .

Title: Re: OS .15 LA-S Question
Post by: John Park on July 23, 2021, 03:26:14 AM

Folks:

Many thanks for all the helpful info.  (I'd hoped the .15 would be like my .46 LA, which had the remote needle mounted on an easily-removable metal bracket, but such is life...)

Regards,
John

Title: Re: OS .15 LA-S Question
Post by: ericrule on July 23, 2021, 10:45:35 AM

We just removed the backplate, sawed off the remote needle and replaced the modified backplate. I strongly suggest putting some RTV silicone on the mating surface to create a gasket. This eliminates any leakage in the future. Also remove and replace the crappy screws with socket head bolts.

Title: Re: OS .15 LA-S Question
Post by: John Park on July 29, 2021, 02:34:01 PM

I bought another backplate, less NVA (it cost less than a takeaway pizza), and a few minutes' work with the electric fretsaw got rid of the unwanted bracket.  (NOTE: I used a jeweller's piercing-saw blade in the fretsaw.  It has ultra-fine teeth and works best for cutting hard plastic, phenolic resin sheet, melamine laminate, polycarbonate etc.)
Thanks for all the advice I've received from everybody.

John