Simon Lumsdon 1

Engines are both in good condition with smooth bearings, o-rings are fine (and i do have spares), think these engines are just very sensitive to idle needle settings. Fuel is also fresh. Think i will stick to OS engines in future

Thanks John, sounds like a similar experience to myself, poor throttling being the main one, point about exhaust pressure makes sense and is going to be very helpful priming a cowled engine. Im also going to buy a Just engines geared starter, current one is too gutless

Well i didnt know the trick with blocking exhaust to draw fuel in so will try that. Will also check plugs are good. Agree with comments about these engines being sensitive to idle valve settings. Thanks

Sorry WOT wide open throttle

So have a couple of SC engines which are very bad starters and looking for advice please. Have googled all the threads on setting up high speed needle, low speed needle and trick blowing air into carb etc but no success. I have checked o-rings but they seem ok. First one is an SC61 in an Extra, inverted,12x6 prop, is a sod to get started but once running goes well, it throttles down ok although low speed idling is poor. High speed is fine, leans out nicely and throttles ok but low speed running a struggle. Getting it to start is hard since its enclosed in a cowl, inverted and doesnt draw fuel well when cranking WOT. Have tried the blowing into fuel feed when throttle open (ok) and when closed (blocked), adjusting idle valve doesnt unblock air flow, should it? Second engine is SC52 and its equally difficult to start, low speed idling is poor as is throttle up. Puzzling thing is neither engine seems any good at drawing fuel when WOT? Using a 12v gel battery and control panel flow feed which work fine on various 4 strokes and an fp40 (but they are all OS) Starter isnt the strongest, do i need a geared starter? Just to be clear, i can get the engines to run eventually and they sort of behave, its initial starting which is the main challenge? All ideas appreciated Many thanks Simon

Many thanks for the feedback on props which is interesting. The OS40FP runs well and is mostly reliable but cant be fully leaned out, never really comes on song which suggests a finer pitch prop might help? Throttle response is not amazing either so will try suggestion of 11x4 instead of 10x6 Have also moved c of g back a bit after mentioning rolls caused the nose to dive, which improved things. Starting to enjoy the model as i get more experience with it. Have now finished a Wot4 with os52fs which will be an interesting comparison, just need the weather to improve now!

The Cougar is flying well (or i am improving), have increased throws to 50% and the FP40 is well suited to the model, starting to get my confidence and started to hoon it around on full power today In hind sight suspect issues were all flying related, c of g, throws and engine are all fine. Adding some circles to the top of the wing is a good shout, it does seem easy to get disorientated with this model, someone commented the purple doesnt help either, although that may also just be inexperience..

Well i built the Cougar and fitted the OS FS 40 and flew it and it was a bit of a handful for a beginner i must admit, had to throttle it right back, it flew ok but felt over powered and a bit twitchy. I managed to get disorientated and binned it which broke back of fuselage at the weekend, decided to fit a good OS FP 40 i had sources on ebay following a previous recommendation, flew it this evening and much much better, smoother and steadier. The FP on a 10x6 is definitely lower powered than a FS 40 Surpass on 11x6. Anyway, quite pleased that i now have a plane which i can hopefully get some time on to improve. Bit disappointed in the build quality of the Cougar, extremely lightly built, just bought a Wot4 artf as its potential replacement and it much more strongly built, we shall see ...

So I have now run in the OS40FS on the bench with a couple of tanks running rich, what a lovely engine, I had forgotten how nice these 4 strokes are. Now bolted into the Cougar and my old Futaba tranny carefully programmed with rates to wind down all the control throws. The C of G was spot on which was one advantage of bolting a big 4 stroke onto it. Looking forward to flying it now and seeing if I have still got it

Thanks Nigel, i didnt realise the 40fs was so powerful, i was working on os 40fs surpass 0.6bhp os 52fs surpass 0.9bhp os 40 fp 1.0bhp os 20 fo 0.5bhp must admit to being fond of OS four strokes, nice and quiet i

Thanks all for the replies and the suggestion to source an OS40FP does make sense although I think I want to avoid any more ebay action otherwise my engine collection will be out of control. I have decided to compromise and use the OS40FS in the Cougar for the mean time and the 52 in the 60. If the 52 is too overpowered I can always replace with the 40 easily enough. David, your ARTF 60 looks great, red and yellow always works. Are those ailerons hinged on the upper edge? My Ben Buckle kit shows central hinges but I was thinking an upper edge film hinge would look better. Does it have dual aileron servos in the wings

Peter, nice model, looks like you have gone for separate servos in the wings, is that a useful mod?

Im now thinking of putting the os fs 40 onto the Cougar (it fits the mount) and use the os 52 fs in the Super 60 on the basis that it seems equivalent to a 40 2 stroke (.9 bhp) and whilst is probably overkill, not madly so, we shall see

Hello Firstly wanted to say hello and thank you for having me on the forum. I am returning to the hobby after a 20 year lay off (kids) being encouraged by lock down to start building again. I have built planes from being a kid in Scotland over 40 years ago so its definitely in the blood. I have just joined a local club and busy building some planes to help me get up to speed again. I seem to have collected a lot of engines so lots of opportunities to keep me busy Engines Cox 049 -sentimental value 1cc Diesel (old) - in an unfinished Vic Smeed Tomboy 1.3cc Mills - planning for a Just Junior PAW 19 RC - planning for a Junior 60 (again) OS 20 FP Courgar? OS 40 FS Surpass Super60? OS 52 FS Surpass I do have a small 3 channel retro electric from an Avicraft kit that i have been cutting my teeth on but looking forward to something bigger. Currently building a Super 60 4 channel and a Cougar 2000 fun fly, again intended to be used initially as a 4 channel trainer. Now onto my engine questions, I was hoping to bolt the 52 onto the Cougar but it looks massive and frankly far too big, question, will the OS20FP be OK for use as a trainer, I think they recommend 25 as a minimum but was hoping I could use the 20 to begin with and move up from there? The alternative is to use the OS FS 40 but again its still looks too big? I dont need the thing to prop hang or climb vertically, just enough for me to get my confidence back after a long time out. On the Super 60, has anyone any experiences of using an OS FS 40 in this model? Had initially thought if using the FP 20 but this looks a bit small in what looks likely to be a largish/heavy model? Thanks for reading and look forward to hearing your advice Simon