Hi Guys,

If someone of you has the Manual for OS.90 FSR, could you please post
it as a photo here, or at least tell please what is written there for the
following basic things:

Max power = ...... bhp
at RPM = .........
Weight = .......
Propellers to use: ....
Fuels to use: .....

and anything else you find good idea to know ?

Thanks in advance,

Regards,
Nick

I don't think your going to find much in the way of a difference between FSR and a current .91 as far as specs are concerned. Not enough to make it worth worrying about at least.

In fact I am exactly interested in the difference between them; people say .90 FSR is more powerful
and better, but no numbers have been posted and that makes it more interesting by how much and
at which conditions ?

I have owned and used the old and new OS91s. The old 90/91 provided a better overall experience. Power between the two was about the same when propped around 11,000 RPM. The new 91 has better power/weight and can be used in smaller airframes. The old engine was heavier but had a better carb and lasted longer.

....12-9, 13-8, 14-6 props. (Not APC [:@])

FBD.

THANK YOU VERY MUCH DAVE !!!!
This makes the things perfectly clear !
[sm=49_49.gif][sm=angel_smile.gif][sm=biggrin.gif]
Nick

So what props are/were they? Or what would you recommend for this engine now? I was just given one of these and came to realize the prop shaft is a bit 'stubby' by todays standards. I put a 14x6 APC on and saw that there wasn't even room for a spinner backplate.

But I found later that a 13x6 APC has a thinner hub. I haven't gotten to the hobby shop to check the thickness of an APC 13x8 tho.

Kerry

The APC may be a good prop for this engine, but less speed than the 13x8.

Some of the APC's have hubs that are too fat, that is one of the reaqsons I don't like them.

Try the regular Zinger 13-8 for excellant performance/speed, or the regular Zinger 14-6 for
general Sport. This is a 14" regular Zinger (not Pro) with a big spinner backplate. There is still
room for a washer and the spinner nut.

FBD.

Flyboy Dave...Do you run your 90FSR on 5% nitro or locally available Powermaster? I add extra castor to all my Powermaster fuel, bought at Hobby People in Redlands, Ca. BTW I have a OS25F that needs a small hub so I run wooden props, the MS are a close fit.

PM me an email address and I will email you a copy of the manual.

That would be great !!!
I just have sent you my PM my E-mail.

....tucker....

....my .90 FSR is still NIB. I run his big brother, the 1.08.

I use Power Master fuel exclusively, I will add extra castor if the engine is new, it is
during the hot season, or the engine is not leaving a satisfactory smoke trail.

I usually don't bother running running 5% nitro for break-in. These engines do not
have high compression ratios. I run them with small diameter props, plenty rich enough
for the prevailing conditions, and with pleny of castor oil in the fuel. I don't let my engines
over heat. If it is not leaving a small (at least) smoke trail, I will bring it in....richen it up,
or add more oil to the fuel.

BTW, most people think the 90 and the 1.08 FSR are the same basic engine, with the same
engine block....they are not....they are different engines.

FBD.

The 90FSR case casting and head was different than the 108. The later (and short lived) 91FSR used the same case casting and head as the 108 with a different name plate, other differences being internal. All versions fit the same mount.

....yep. The only obvious similar parts on the 90 and 108 is the engine backplate. The crankshaft
is different. The carbs are different too, even though they are both marked 7D. The 90 carb body
is psysically smaller than the 7D on the 108.

FBD.

Hi NikolayTT , iv just picked up an old 90fsr looks and feels in good nick, alas its without silencer or adapter so im on a hunt for those as we speak --- anyway I have also managed to get my hands on a copy of radio modeller 1981 with a bench test and write up of the 90fsr, if you want I could always scan you a copy of the bench test and mail it

Hi Omally,

I remain interested in FSR .90. I got an offer for one but it was in very bad shape
and price was irrealistic, almost like for a new OS.91FX.
I will appreaciate very much if you mails those things - I am very currious.
My E-mail is [email protected].

Thanks,
Nick

Hi Omally,

I have replied to your E-mail immediately as I received the pictures and
I replied righ min ago to your E-mail again but it seems that you have not
got the reply. Here below is my original E-mail sent on 10-Sep-07
at 7:26 pm; please confirm for receiving it. Thanks a lot !

-------------
Hi Omally,

Every picture of the three(3) attached is in very good quality
and full of very valuable information. Thank you very much!

Now I know that this is really very good engine and also how
a good review is to be done. Nowadays such review I do not
find frequently.

Best regards,
Nikolay
------------------------

Glad you got em ok Nikolay had a few probs with my mail not getting through to folk over the last week, last one you sent landed fine [sm=thumbs_up.gif]


omally