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KawasakiCraig

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Posts posted by KawasakiCraig

  1. I have a Mosquito with two OS 52 FS second hand engines in and both seem to start pretty well but when I try to run the engines up to full throttle they struggle at about the half way point and then quit on me.

     

    I have tried to alter the main needle when the engine gets to about half revs but it doesn't seem to make much difference, any ideas?

  2. I can't believe the price of nitro fuel especially when it comes to helicopter fuel with a high nitro content, of course I need a high oil content as well.

     

    I have a Raptor V2 and a Weston UK Velocity I like to run on these type of fuels.

     

    They seem to be priced any where from £30 to £40 for a gallon, it wouldn't be so bad if I didn't need it delivered but of course this makes it even more expensive.

     

    Does anyone know a cheaper alternative?

     

  3. 42 minutes ago, Ron Gray said:

    Lots of people on this forum have a wealth of knowledge far greater than mine Craig so you’ll get a lot of helpful advice, just try them out one at a time!

    Yes other people on here have been great too, I appreciate yours and everyone's help on here, I now have a better understanding with what was going on.

    It's funny because I can do most things and also have a fair knowledge of mechanics, I work on cars, motorcycles etc all the time so I should have been able to diagnose the problem myself and I've been r/c modelling for quite sometime now but I clearly failed when it came to an inverted engine lol... 

  4. 15 minutes ago, Ron Gray said:

    If the revs drop it can indicate that the plug is cooling caused by an excess of fuel so lean the low first then re-tune the top. You’re aiming to get it so that the motor transitions from low revs to high without hesitation or stuttering.

    Okey dokey I'll have ago, you obviously know your stuff I can tell, thanks Ron...

  5. 1 hour ago, Peter Christy said:

    No! No! No! Do NOT run it on high nitro fuel! They were designed to run on STRAIGHT fuel (no nitro at all)!

     

    Unless you have some serious shims under the head, it will run like a dog and be difficult to tune!

     

    I run all my STs (and my old Webras) on straight, and they run like sewing machines on it.

     

    A good way to set the carb up is 1) aim the inlet nipple at the front mounting bolt. 2) open the main needle quite wide, then close the carb to the point where it just traps a pin. Then attach a length of fuel tubing to the inlet and blow. Adjust the idle needle until you can JUST hear the faint hiss of air getting through. 3) put the main needle back to a slightly rich running setting.

     

    Setting it up this way will get you very close to a good running setting, and you should only have to do fine tuning to get it spot on.

     

    I cannot emphasise enough how - unless you put some thick shims under the head - an ST will never run properly with high nitro fuel! They don't need it, don't like it, and it costs you money! Don't do it!

     

    --

    Pete

     

    I hear you Pete lol... I'm used to using high nitro on my helicopter OS motor and my Weston UK Velocity. I thought it could only be a good thing to use that fuel on the Super Tigre as well and give me lots of power hehe. Okay I'll some different glow fuel, think I have some other kicking about the garage. I think I have it close to being setup nice  but I will definitely take note of how you told me to set it up, thanks for the info...

    Oh, I've seen people saying to point the inlet nipple at the rear mounting bolt???

  6. I'm presuming I done this right but this afternoon I measured the height of the fuel tank tubing coming out of the neck to be level with the spray bar on the carb and before It was out by 40mm, what does anyone make of this, does this sound like a better setup?

  7. 6 hours ago, Andy Stephenson said:

    It seems ST engines are difficult to tune. One club member had one which gave no clue we were edging close to the correct setting until we finally found it. We could blame it on the rather quirky carbs they use but the strange thing was, they worked perfectly well on early Laser engines.

    I have heard that ST engines tend to have rather small transfer ports which contributes to tuning problems.

    I must admit I have not had trouble quite like this with any other glow engine!

  8. 22 minutes ago, Ron Gray said:

    I may have not interpreted previous posts correctly but have you tried bench running it inverted (with the tank rotated of course!) using your ‘crude’ mounting system?

    I haven't yet to be honest, the only thing I done was I removed it from the vice and turned the whole thing upside down whilst it was running, seem to go quite well until I moved the throttle to idle and then it cut...

  9. 43 minutes ago, Engine Doctor said:

    That glow clip you have fitted is a large heat sink and will try to cool the plug. Try  a lighter commercial type 

    What fuel are you using. Too much oil will puddle into the plug when inverted. Try a lower oil content  say 15 %. Still plenty for the engine.

    When you stripped send cleaned it did you make sure that crankcase compression is good ? Any leaks will cause erratic running.

    Is cylinder compression good ? If piston ring is worn and compression is low this can also add to erratic running.

    Hope you get it sorted.

    I can imagine it would act like a heat sink. I have been using different types of fuel one of them being Opti Fuel 20% nitro and 18% oil. I haven't taken the piston out to check the piston ring but compression is very good and I'm pretty sure there aren't any leaks.

    Thanks for your help too...

  10. 4 hours ago, Peter Christy said:

    Re: Tank pressure - yes that is what I was referring to. If the tank is too high (as suggested), then the pressure feed will make matters worse! Depending on the bore of the carb, you may not need pressure, but it is one more variable to consider. If the engine runs fine without it, then its something else to go wrong, but it is often useful if the tank is some distance back from the engine, and it is a big bore carb (not enough venturi suction to keep the fuel flowing!).

     

    Regarding the plug, yes an OS 8 is a very good plug, but it is also a bit short for the ST! If you take the head off you will see that it stops several turns short of the combustion chamber! As Jon has suggested, best to turn it over by hand first to make sure the clearance is OK with a 4-stroke plug, but I've never had an issue with smaller STs (up to 60-size) or Webra Blackheads using them.

     

    --

    Pete

    I am overwhelmed with all the help and useful information everyone has sent me, it's amazing. I did at one stage take the pipe off the exhaust to see if that would make a difference but at the time it didn't, I figured I was still doing something wrong. The setup at the moment as you can see in the photo's is working a lot better after tweaking the settings however when I turn this upside down it still cuts on idle. I now know the tank isn't in the ideal position but this is just temporary until I can get back to work on it.

    Thanks about the plug thing I understand and I will get one me thinks for sure...

  11. 4 hours ago, Martin Dance 1 said:

    Looking at your photo and taking into account the angle at which it is taken I think your fuel tank is too high. In an inverted setup I would expect the bottom of the tank to be almost level with the top of the head so that the top of the tank is level with or just higher than the spraybar. I've used ST engines a lot and they do idle reliably. If you have an engine test stand. Set the motor up in an upright position with the top of the fuel tank a little above the spray bar, about 8-12mm. I aim for the motor to idle reliably at around 2000rpm for one minute and then to accelerate to full power with a brisk opening of the throttle without sagging or mis-firing or producing clouds of smoke. My reasoning for choosing  one minute of idling is two fold. 1 It gives the engine time to cool a little and this will magnfy any poor carb  setting. 2. If you are doing a landing approach, chances are you will be closing the throttle going downwind just about in front of you. by the time you turn onto finals the engine will be at idle., If you decide to go around you need the motor to accelerate cleanly. For many models the time taken to complete the dowwind leg, crosswind leg and finals is about a minute. So aiming for at least a minute idle is a reasonable goal.

    Once your engine is set up in the upright position it should need little or no further adjustment

     

    Thanks Martin I found this very interesting as well as the other useful information people have kindly given too. It's funny when you say about the landing part because I had that very thing happen to me where I came in a little bit too fast (idle was set fast to keep the dam thing running) so I decided to go around and try again, I blipped the throttle and the motor cut (oh bugger), because I was dead stick and still going at some pace I gave a little to much bit too much elevator to bleed some speed off, slightly stalled it and hit the ground too hard and it broke the nose off along with the motor.

    If the Spitfire which I was flying was fitted with flaps it might have been a successful landing even though the engine was idling fast. So yes it would help a lot if I didn't have to worry about the engine potentially quitting on me especially when taking off or on finals!

    Oh I thought I would upload another photo the engine in my crudely setup in my vice showing the tank and in it's temporary position.

     

    RemoteGlow2.JPG

  12. Okay I still haven't got the engine back in the plane yet but I have got it running better bench testing it. I will of course from peoples help on here check the position of the tank in relation to the spray bar.

    I have made some fittings on the glow plug so I can run a 1.5v battery internally in the plane and have it setup mechanically so that when the throttle servo arms moves to idle it will make a connection and put power the glow plug and hopefully keep the engine running that way. I could of bought an onboard glow system for this purpose but I'm tight lol.

    Here's what I have done so far in the photo. I crimped a wire to a electrical ring connector so it is help in position when the glow plug is put in and I used an old cog with a grub screw in so I can tighten it to the top of the glow plug and screwed in another wire to the top of it, Just got to sort out the other end now.

    RemoteGlow.JPG

  13. 4 hours ago, John Wagg said:

    My original thought was try a different plug. Then came tank position. Regarding the tank I also wondered if the pick-up was jammed so that when inverted the pick-up sucked air. Unlikely but I have known it happen. Easy to check as wobbling the plane vertical you should hear the clunk of the pick-up.

    Yes I know that can happen or the classic one is where the clunk double backs on itself perhaps after a hard landing and the next time you go to run the engine you get problems or people use too stiff a tubing etc, I'm wise to these things but thanks for your help...

  14. 1 minute ago, Jon - Laser Engines said:

    If you have tuned the engine to work well upright and it stops as soon as you turn it over then tank placement is my suspicion just as the others have said. 

     

    I recommend you level the top of the tank with the centreline of the carb. This will prevent fuel syphon when the engine is sat on the ground and prevent ground flooding. 

     

    the OS F plug trick is a good one and can work well. However once fitted the first time be very careful when you turn the engine over as you may find that the plug is too long on some engines and you will punch a hole through the piston if you just fit it and try to fire it up. 

     

    I would also consider the fuel you are using as ST engines tend to like less nitro. 

    Okay noted, with a longer plug I'll turn the engine over by hand with out the glow stick connected of course and check for clearance, thanks for the info...

  15. 43 minutes ago, Peter Christy said:

    Super-Tigres - in common with a lot of older European engines - were designed to run on long-reach plugs. The only long-reach plugs currently available (of which I'm aware) are 4-stroke plugs, hence the recommendation for the OS "F" plug.

     

    4-stroke plugs are also "hot" plugs, which makes them better suited to the straight fuel (no nitro) recommended for Super-Tigres.

     

    As mentioned above, its also worth checking the tank height. Also, are you using a pressure feed?

     

    A short-reach plug in a long-reach head will work, but it will be much easier to flood the plug - especially when inverted - as the fuel will tend to collect in the "cup" formed by the empty part of the threaded section of the head.

     

    --

    Pete

    The tank is pressure fed from the exhaust if that's what you mean? I didn't occur to me about the plug not being long enough and I can imagine what you mean with the fuel collecting in the head. I have been using OS no8 plugs mostly, maybe I should try a long reach one then as well..

     

    Thanks Pete 

  16. 1 hour ago, Frank Skilbeck said:

    It should run fine inverted, so check the tank position etc. I have a couple of the model radio shop remote glows, useful for engines where fitting a glow stick isn't easy. But if you want to go the cheapskate route one of these activated by the throttle servo control horn might be more reliable than a couple of metal strips.

    Okay cool, that would work great I reckon with that micro switch, thanks..

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