Stevo Posted July 26, 2014 Share Posted July 26, 2014 One OS 48 Surpass, inverted. Been through the usual, tank height good... all plumbing good... plug good... It has an airbleed screw and not the twin screw of later engines. Weakned the bottom end. No difference at all. Tuned top end no difference. Nice stable idle when glow is ON. Turn glow OFF and she cuts out. What are the latest remote glow recommendations? Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted July 26, 2014 Share Posted July 26, 2014 Personally I'd be tempted to try an extra 5% nitro in the fuel first as this retains the heat of combustion and means you don't get the extra complexity of on-board glow and the weight of the battery. What fuel are you using and what glowplug? Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 26, 2014 Author Share Posted July 26, 2014 10% irvine (works on all my others...) and an OS 'F' Quote Link to comment Share on other sites More sharing options...
Jamie sawyer Posted July 26, 2014 Share Posted July 26, 2014 Does it run ok up the right way Stevo ? Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 26, 2014 Author Share Posted July 26, 2014 erm... yep I run it in the test stand it's fine, however if I invert the model it floods iteslf eventually via the exhaust Quote Link to comment Share on other sites More sharing options...
jrman Posted July 26, 2014 Share Posted July 26, 2014 I would recommend the Just Engines remote glow. I've got 4 of them and they do exactly what you want. Full on at idle then progressively pulse and reduce until they're off at about 1/3 -1/2 throttle. Switch the radio off and they are off as well, no separate switch required. Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 26, 2014 Author Share Posted July 26, 2014 I always look at 'jrman' whan it appears in threads... so close to my second name it's spooky. I think you may have it there jrman.. I'll go for the 'no battery' option as I have some NiMhs with tags one somewhere... Quote Link to comment Share on other sites More sharing options...
jrman Posted July 26, 2014 Share Posted July 26, 2014 I don't think you'll be disappointed. I can get down to a tick over of about 1800 rpm on an OS 120pumped with a Xoar 18/6 prop.I don't know how I feel knowing I'm being looked at !! Quote Link to comment Share on other sites More sharing options...
.. Posted July 26, 2014 Share Posted July 26, 2014 PM sent Stevo Quote Link to comment Share on other sites More sharing options...
cymaz Posted July 27, 2014 Share Posted July 27, 2014 Have you tried putting a loop of fuel tube up and over the engine before going to the carb. The fuel then has to travel up hill and it may stop the siphoning and put in a fuel filter to add some resistance to the fuel. The filter will be ok for flying. Edited By cymaz on 27/07/2014 07:04:52 Quote Link to comment Share on other sites More sharing options...
Jon H Posted July 27, 2014 Share Posted July 27, 2014 Its possible the slow run setting to too lean (sounds weird but trust me). You should do all tuning with the glow off otherwise you stand no chance of finding the correct setting. Start with the airbleed screw halfway across the little hole and give it another go Avoid using remote glows at all costs. they cause more problems than they avoid Edited By Jon Harper on 27/07/2014 09:27:07 Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 27, 2014 Author Share Posted July 27, 2014 Hi all and thanks for replies. Cymaz, yes I've looped it 'up and over' ... Shouldn't syphon too much as it is deigned to be installed inverted, and carb centre line etc is in the right place. Jon, agreed , it should run happy inverted. Fortunately I designed a glow starter with integral timer and on/off switch so I dont have to keep plugging in in and out. All tuning done with glow off, and for safety's sake make sure it's OFF at full bore else I get some banging noises and the prop loosens off of course. Regards the low end adjustment, I've had the screw right in, (rich)... I've had the screw right out (lean) halfway (middle) to no avail. I had this in a Saito 50, bless it, all I did was weaken the bottom end, and it was sort of happy, but has to maintain a fast idle to keep it stable. I don't believe glow drivers are the answer to everything of course, but I would like that insurance of a reliable idle on landing on all my models, and for this reaon alone I'll install a glow diver - but no excuse for not tuning! Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted July 27, 2014 Share Posted July 27, 2014 Posted by Jon Harper on 27/07/2014 09:26:21: Its possible the slow run setting to too lean (sounds weird but trust me). You should do all tuning with the glow off otherwise you stand no chance of finding the correct setting. Start with the airbleed screw halfway across the little hole and give it another go Avoid using remote glows at all costs. they cause more problems than they avoid Edited By Jon Harper on 27/07/2014 09:27:07 Yes, absolutely agree with the comment about remote glows, especially the ones that claim to be 'intelligent' or have a delay in shutting off when the throttle is advanced. (helps with clean pick up........rubbish, make sure the motor is well run-in, you're not running with too low nitro content, and set the slow running correctly in the first place). Some installations are a bit touchy at slow running, so if after all the usual remedies are exhausted, only use a simple on board glow as a last resort, and one that can be adjusted on/off no higher than 1/4 throttle. Edited By Cuban8 on 27/07/2014 11:03:32 Edited By Cuban8 on 27/07/2014 11:07:15 Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 27, 2014 Author Share Posted July 27, 2014 "only use a simple on board glow that can be adjusted on/off no higher than 1/4 throttle." Thanks Cuban8... my sentiments - I think our posts crossed ! I do like the electronics & technology behind the remote glows, and I have programmed PICs to do this simple task... when it takes £10 worth of bits and 2Hrs of fiddly soldering, or £25 for a new and tested one I know which way I now prefer. Yes it's easy to get carried away with all that and I don't intend to. For years we have done without them, some modellers even putting a cam / microswitch arrangement on thier installations for a bit of insurance at low throttle, especially on that 2 year project scale biplane...! As I said, tuning, tuning, tuning, tuning... plus low idle insurance with a glow switch, as you say no higher than 25% throttle. Interesting, the remote glow debate always attracts lively comments about the pros and cons Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 27, 2014 Author Share Posted July 27, 2014 Ok some progress. Ordered a glow switch and some NiMh batteries... Spent some time with the aircraft. The throttle linkage had some hysterisis so moved servo around and adjusted accordingly. No slop no nothing. Almost there. Removed cowl, checked and adjusted end points. Looked at the air bleed hole and got used to the adjustment screw range. Adjusted so that screw was around 1/2 way. Started engine. Would not run without glow connected, throughout the range!. I had to weaken the top end right out to max revs - and of course back off to get her running rich again. Went back down to idle - it got very lumpy after 5-10 seconds so wound air bleed screw out by 1/2 turn. Now I get a good idle, if a little fast. At this idle, the aircraft starts to move on the ground... Wound the idle down a bit and again she got lumpy, but carried on regardless. Switched on the glow... and normal service was resumed. So, I will install a glow driver, as I said for insurance... coming on around 15-20% throttle. Not out of the woods, but right on the edge of the forest!!!! Quote Link to comment Share on other sites More sharing options...
Jon H Posted July 28, 2014 Share Posted July 28, 2014 When you say you lean off for max revs and then back off to run rich, why are you doing that? there is no need to richen from the peak rpm as long as you have not gone past the peak it will be fine. If you do go rich to play safe then 2 clicks of the needle should be more than enough Quote Link to comment Share on other sites More sharing options...
Stevo Posted July 28, 2014 Author Share Posted July 28, 2014 Indeed John... I hit full throttle, wind in the needle until she screams, and then back off 2-3 clicks... That's my top end set. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted August 2, 2014 Share Posted August 2, 2014 What plug are you using Stevo......the OS F plugs are excellent in 4 strokes. I wonder if one of these plus a tad more nitro might solve your problem..... Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted August 2, 2014 Share Posted August 2, 2014 Err I might have suggested the same thing in post #2......Deja vu all over again! Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted August 2, 2014 Share Posted August 2, 2014 Ooops.....must pay more attention... Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 3, 2014 Share Posted August 3, 2014 I have a 48 Surpass inverted in my Eros and I have to say that on the odd occassion that I drag it out it bubmles along quite happily. When I first installed it I did have problems with inconsistent running but that turned out to be the fuel nipple was loose in it's thread in the carb body. Tightened it up, problem solved. OS-F, 5% nitro. Quote Link to comment Share on other sites More sharing options...
Former Member Posted August 3, 2014 Share Posted August 3, 2014 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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