Jon H Posted May 22, 2020 Author Share Posted May 22, 2020 I have used menz wood props without issue. all of my engines over a 180 use wood props. Link to comment Share on other sites More sharing options...
David Davis Posted May 23, 2020 Share Posted May 23, 2020 Hi Jon, I have two Laser engines currently installed in models, an old 150V in a WOT 4 XL and a 70 in a Big Guff vintage model which is close to completion. I am currently running the V twin on a fuel supplied by Southern Modelcraft which consists of 75% methanol,10% nitro and 15% oil, of which the oil content is made up 13% synthetic 2% castor which I bought to suit my Japanese and Taiwanese four strokes. I also have stocks of Southern Modelcraft straight fuel, 85% methanol and 15% oil, again, 13% synthetic 2% castor. I can buy both methanol and nitro from my club. I see that you are recommending the use of 7.5% oil in Laser engines. If I were to turn up with 5 litres of straight at my club's workshop and bung it into a large clean bucket and add 5 litres of methanol, by my maths I would then have 10 litres of straight fuel with a 7.5% oil content. If I were to add 0.5 litres of nitro I would acheive your favoured Laser fuel mix. So two questions: Would you recommend this fuel for the old 150V? Would the 70 be alright with this fuel? I have run up the engine on the test stand with the 10% nitro mix. Edited By David Davis on 23/05/2020 13:58:42 Link to comment Share on other sites More sharing options...
Jon H Posted May 23, 2020 Author Share Posted May 23, 2020 On the 150v i would stick to 15% oil. Synthetic is fine but 15% is probably a good idea as they were not built to the same standard or with the same materials as later engines. On new Lasers 5 nitro and 10 oil is totally fine and we are working on lower oil still I wouldnt use more than 5 nitro, you just dont need it and it really increases fuel consumption Link to comment Share on other sites More sharing options...
Ace Posted May 24, 2020 Share Posted May 24, 2020 Similar question regarding a Laser 100 with the single bolt valve cover and silver TT? carb. Is it ok to use the same fuel as in my new Lasers - S/Modelcraft 10% fully synthetic, 5% nitro? ( I don't mind some risk if its marginal and accept its not a company recommendation and just an informed opinion ) Link to comment Share on other sites More sharing options...
Jon H Posted May 24, 2020 Author Share Posted May 24, 2020 all engines built after 1992 have hardened cranks and should be quite happy with the low oil. Exceptions to this would be corrosion on the crank pin or some other issue but in general it should be fine Link to comment Share on other sites More sharing options...
Engine Doctor Posted May 24, 2020 Share Posted May 24, 2020 Dave when you have used your existing fuel replace it with the fully synthetic. Even 2% castor makes a mess and cokes parts up . Southern model craft fuel is good honest fuel and Dave will tel you exactly whats in it . Used SMC fuel for years and never had a problem . Link to comment Share on other sites More sharing options...
Ace Posted May 24, 2020 Share Posted May 24, 2020 As ED have used it for years and now use S/Modelcraft 5l 10% nitro Hi -Lube (20% fully synthetic) + 5l Methanol = 10l, 10% oil, 5% nitro in my Lasers. I then use std 10 % Hi Lube in all other 2/4 s. Link to comment Share on other sites More sharing options...
Rocker Posted May 29, 2020 Share Posted May 29, 2020 Hi I have a Laser 80 and it is not running right. It OK at full throttle but erratic at mid range .I retune the slow running needle valve like Jon show in he's video ,it is a bit better but just can not get it to run right in the mid range .I then look at the valve clearances and the inlet valve was fine but the exhaust valve had no clearance what's so ever .I have now adjusted the valve clearance on both valve to so the 0.004 feeler gauge goes through and the 0.10 does not .Due to our club field still being closed ( tell me about it ) I can not check it in flight .It seems to run fine on the ground .Would the exhaust valve having no clearance make much difference to the mid range running of the engine or am I just hoping it did ? Link to comment Share on other sites More sharing options...
ken anderson. Posted May 29, 2020 Share Posted May 29, 2020 hello rocker,Jon is the man...but I think you may have found and solved the problem your self.....if the exhaust valve had no clearance imagine when it was hot it wouldn't be able to function correct(close/seal)….see what the main man says. ken anderson...ne..1...…. E/V dept. Link to comment Share on other sites More sharing options...
Jon H Posted May 29, 2020 Author Share Posted May 29, 2020 Hi Rocker The basics: What fuel, prop, plug and top end RPM? Valve clearance can have an impact but usually its small unless they are massively wide. My quick and dirty method of setting valves is to tighten until no clearance and they slacken the screw about 1/8 turn. Its not perfect but works well enough if you are in the field or dont have all the tools to hand. frankly, its accurate enough for our purposes anyway so dont loose too much sleep over a thou or 2 of valve clearance. Link to comment Share on other sites More sharing options...
bert baker Posted May 29, 2020 Share Posted May 29, 2020 Get a new carb,, might be unmetered air getting in Link to comment Share on other sites More sharing options...
Rocker Posted May 29, 2020 Share Posted May 29, 2020 Hi Jon, I have the Laser 80 in a Seagull Fokker C1 ,which is basically a Bowers Flybaby in disguise. The exhaust valve had no clearance what so ever but the inlet was fine .I have now adjusted the valves to 0.004 .I am using Model Tec Laser fuel and I have a 14x7 prop on it . Has I said I have adjusted the slow running needle valve like you showed in the video and it was a lot better but still ran a bit erratic at mid range .Then I discover the exhaust valve had no clearance it was tight up against the rocker so I adjusted it to 0.004 .It seems better but I have not try it in flight yet .Would the tight exhaust valve be the cause of it running a bi erratic at mid range ? Link to comment Share on other sites More sharing options...
Rocker Posted May 29, 2020 Share Posted May 29, 2020 Hi Jon, I have the Laser 80 in a Seagull Fokker C1 ,which is basically a Bowers Flybaby in disguise. The exhaust valve had no clearance what so ever but the inlet was fine .I have now adjusted the valves to 0.004 .I am using Model Tec Laser fuel and I have a 14x7 prop on it . Has I said I have adjusted the slow running needle valve like you showed in the video and it was a lot better but still ran a bit erratic at mid range .Then I discover the exhaust valve had no clearance it was tight up against the rocker so I adjusted it to 0.004 .It seems better but I have not try it in flight yet .Would the tight exhaust valve be the cause of it running a bit erratic at mid range ? Edited By Rocker on 29/05/2020 10:53:14 Link to comment Share on other sites More sharing options...
Jon H Posted May 29, 2020 Author Share Posted May 29, 2020 Posted by bert baker on 29/05/2020 10:41:17: Get a new carb,, might be unmetered air getting in Nothing personal but i always see this advice and totally disagree with it. In 25 years i have only ever had to replace 2 carbs. 1 due to crash damage and 1 that was worn out so just replacing the carb as a first port of call is a little premature. Its also not very cost effective as 90% of erratic running problems come down to either poor fuel, poor plug, or bad tuning. While its true air leaks can cause problems its rare that an entire carb need to be replaced in order to fix it. Rocker, the valve clearance is not critical so i doubt it is the cause of the problem. My suspicions are still plug/tuning. When you say you set the engine up according to my video, how far did you go leaning off the slow run? In my experience most chicken out early so its possible you have a little more leaning to do. If in doubt, shoot a video (without the camera in the prop wash!) and upload it you youtube as an unlisted video. You can then post the link here and we can have a listen Link to comment Share on other sites More sharing options...
cymaz Posted May 29, 2020 Share Posted May 29, 2020 If I have any run issues with a glow the first thing is to toss the old plug and put on a new one. Edited By cymaz on 29/05/2020 11:57:58 Link to comment Share on other sites More sharing options...
tigerman Posted May 29, 2020 Share Posted May 29, 2020 Hi Jon , Tried to down load the video but failed .It would not download into my album so I could not post it .It was only a few seconds long .Do not know what went wrong Link to comment Share on other sites More sharing options...
cymaz Posted May 29, 2020 Share Posted May 29, 2020 Load it onto youtube then use the YouTube icon above in the icon / menu bar. P.S. you will need a yt account if you haven’t got one already.. Edited By cymaz on 29/05/2020 13:12:29 Link to comment Share on other sites More sharing options...
bert baker Posted May 29, 2020 Share Posted May 29, 2020 Be quicker to pop the engine in the post Jon had his fingers on my 180 last year was quick turn around and very pleased 😀 Link to comment Share on other sites More sharing options...
tigerman Posted June 2, 2020 Share Posted June 2, 2020 Hi Jon I did what you surgested about leaning the slow running needle more and BINGO .the Laser 80 runs has sweet has a nut again At low rev middle range and at full chat .Thanks Link to comment Share on other sites More sharing options...
Rocker Posted June 2, 2020 Share Posted June 2, 2020 Just a quick qustion .Will the Laser 180 fly the Seagull Hurricane 2083 mm ? Link to comment Share on other sites More sharing options...
Tim Flyer Posted June 2, 2020 Share Posted June 2, 2020 Hi Rocker yes it will with plenty of power although there are a number of issues with the plane. I have one powered by the Laser 180 and there is a quite detailed thread on it . Which I will link https://www.modelflying.co.uk/forums/postings.asp?th=140639&p=1 a lot of my assembly notes are on this thread https://www.modelflying.co.uk/forums/postings.asp?th=124909&p=2 Edited By Tim Flyer on 02/06/2020 20:27:18 Edited By Tim Flyer on 02/06/2020 20:29:15 Link to comment Share on other sites More sharing options...
Jon H Posted June 2, 2020 Author Share Posted June 2, 2020 Posted by Rocker on 02/06/2020 18:54:44: Just a quick qustion .Will the Laser 180 fly the Seagull Hurricane 2083 mm ? It sure will but as Tim says there are other issues to consider. Again the threads he linked show the full story but the short version is we have two of these powered by laser 180's and while both fly fine they are a right faff to land. I flew Tim's about 3 or 4 times i think but must have in excess of 20 landings on Chris's model as i just kept shooting approaches with it. If we assume 25 landings total over the 2 models i think only 4 were of a standard i would consider acceptable. What i cant work out is why its so hard to get them right. Approaches feel lovely and stable yet the flare/touchdown is a nightmare. At some stage we are going to try and get all 3 of us together and work out exactly what is going on. Unless we can work out a very specific recipe of balance/control throws etc then it might be a bit of a struggle. Link to comment Share on other sites More sharing options...
David Davis Posted June 8, 2020 Share Posted June 8, 2020 I flew the Big Guff for the first time yesterday. The model weighs 8lbs 9ozs but there is ten square feet of wing area so I was flying it around on a slow tick over most of the time. The model is fitted with a Laser 70, I am using 5% nitro, 15% oil fuel and a 13x6 prop. I have a 13x4 prop. Would that suit the model better? Link to comment Share on other sites More sharing options...
Jon H Posted June 8, 2020 Author Share Posted June 8, 2020 It will rev like mad on 13x4. Try 14x5 or 15x5 if you can find one. 15x4 would also work, i think even 16x4 if it exists. Given the nature of the model you can really load the engine up with whatever you like. As its going to float around at low power the engine will not be stressed that much. I use a 15x5 turnigy wooden prop on my saito 45 and the poor little thing can only manage about 6000rpm. As i only need about 4500 to fly it works out well. The turnigy prop im using does fun fast though so its probably equivalent to 14x5 from another brand. Link to comment Share on other sites More sharing options...
David Davis Posted June 8, 2020 Share Posted June 8, 2020 Amongst my collection Jon i have a 14x6, a 15x6 wood and a 16x4 wide APC. I'll try the 16x4 on Wernesday. Edited By David Davis on 08/06/2020 11:17:35 Link to comment Share on other sites More sharing options...
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