Jon H Posted December 17, 2019 Author Share Posted December 17, 2019 hi Paul The taller engine is an old 90. The shorter one is an 80 as it will have 27.7mm bore and 22.2 stroke. We have never used a 28.7 bores or 22.9 strokes on any engine. Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted December 17, 2019 Share Posted December 17, 2019 Any possibility it could be one of the African made knock offs? Those dimensions are close to 1.25" x 0.9" if that might be significant. Link to comment Share on other sites More sharing options...
Jon H Posted December 17, 2019 Author Share Posted December 17, 2019 Posted by Martin Harris on 17/12/2019 15:04:24: Any possibility it could be one of the African made knock offs? Those dimensions are close to 1.25" x 0.9" if that might be significant. i think they only cloned the 150 and they should be 26.9x33.5 bore/stroke Link to comment Share on other sites More sharing options...
Andy Stephenson Posted December 17, 2019 Share Posted December 17, 2019 Posted by trebor on 14/12/2017 18:23:24: I'll start this off then ! Can you take the end of the silencer to clean the inside out or is it pressed in ? Ps Thanks for the advise earlier and I'll post a picture of the engines after I've finished cleaning I forgot the worst bits the silencers Trebor, When I asked Neil Tidy how to clean a Laser silencer, he said to put a 3/8" drill down the tail pipe and drill out the crud. Andy. Link to comment Share on other sites More sharing options...
Jon H Posted December 17, 2019 Author Share Posted December 17, 2019 Posted by Andy Stephenson on 17/12/2019 18:27:28: Posted by trebor on 14/12/2017 18:23:24: I'll start this off then ! Can you take the end of the silencer to clean the inside out or is it pressed in ? Ps Thanks for the advise earlier and I'll post a picture of the engines after I've finished cleaning I forgot the worst bits the silencers Trebor, When I asked Neil Tidy how to clean a Laser silencer, he said to put a 3/8" drill down the tail pipe and drill out the crud. Andy. this will mostly work but you end up drilling through the baffle as well so you end up with more noise. the best bet is to never let it get all grotty in the first place by not using any castor Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted December 24, 2019 Share Posted December 24, 2019 Just putting a Laser 62 I acquired in a Majestic Major, not done much running but bearings were gummed up and have been replaced. While rummaging through my prop drawer I came across an 15 x 4 prop, worth a try or too much for a 62? Link to comment Share on other sites More sharing options...
Andy Stephenson Posted December 26, 2019 Share Posted December 26, 2019 this will mostly work but you end up drilling through the baffle as well so you end up with more noise. the best bet is to never let it get all grotty in the first place by not using any castor Jon, Neil was not suggesting that the drill went any further in than would ream out the coke in the tail pipe, certainly not through any metal inside the silencer. This was a while ago before he changed to recommending synthetic fuels, although the some still have a small proportion of castor and create carbon deposits. Andy. Link to comment Share on other sites More sharing options...
Jon H Posted December 27, 2019 Author Share Posted December 27, 2019 Frank, give the 15x4 a shot. On a model like that it should work well Andy, 3/8 will wipe out the baffle on both sizes of exhaust. Our exhaust is designed with two gas paths and carbon always blocks the one hidden from view within the exhaust. As a consequence you need to make the remaining path bigger to prevent back pressure increase by drilling through the baffle and this is what Neil always used to recommend. Its not really a problem now with synthetic oil but in the days of 20% castor an exhaust might only last a year to two before it was blocked. Link to comment Share on other sites More sharing options...
Andy Stephenson Posted December 27, 2019 Share Posted December 27, 2019 Jon, This was on a 150 and I only reamed the deposits by hand and no metal was removed as a result of my taking this advice. I also I believe this was only a partial solution but the best that could be achieved mechanically. Andy. Link to comment Share on other sites More sharing options...
Jon H Posted December 27, 2019 Author Share Posted December 27, 2019 That's fair enough but the intention behind the recommendation was always to drill through the baffle. Its the only way short of replacement to restore the exit area of the exhaust after the internal passages are blocked but it is only a bodge job solution. Once the exhaust is blocked to the degree that any of this becomes relevant its better to just buy a replacement exhaust and be done with it. In the days of 20% castor this meant a new exhaust every few years and people used to complain they needed an exhaust so frequently. Drilling though it was a free bodge that was well received as it saved the 20 quid for a new exhaust. Unfortunately its now fallen into folk lore as a viable engineering solution when in reality its nothing more than a bandage on a broken leg. Unless you have a 75 or other unsupported engine its better to just buy a new exhaust and use synthetic oil in your fuel. If you do that the exhaust will never need replacement unless it either falls off or is damaged in a crash. Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 27, 2019 Share Posted December 27, 2019 If you can still find anywhere selling it, Fairy Power Spray is very effective on grunged up engines and exhausts. Just leave it on for a while then wash off. Link to comment Share on other sites More sharing options...
Paul james 8 Posted December 27, 2019 Share Posted December 27, 2019 No need to hunt for that, just use aerial biological washing powder and hot water, works a treat!! Link to comment Share on other sites More sharing options...
Ace Posted December 28, 2019 Share Posted December 28, 2019 Caution - Fairy Power Spray turned the alloy on either an ASP or SC 2* very dark grey when I tried it several years ago. Now what I can't recall is how long I left it on It did clean the engine but chemically changed the colour permanently. Link to comment Share on other sites More sharing options...
cymaz Posted December 29, 2019 Share Posted December 29, 2019 Jon, there’s a Russian Bear with 4 x Laser v twin engines on it. Have you seen it on YouTube? Edited By cymaz on 29/12/2019 17:43:53 Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted January 1, 2020 Share Posted January 1, 2020 Posted by Jon - Laser Engines on 27/12/2019 12:55:12: Frank, give the 15x4 a shot. On a model like that it should work well Yep flew it today, Majestic Major + Laser 62 + 15 x 4 prop = . Turned the 15 x 4 around 7,700 rpm on Southern Model craft 5%, pottered around on 50% throttle Link to comment Share on other sites More sharing options...
Jon H Posted January 1, 2020 Author Share Posted January 1, 2020 good stuff Frank. I had 8000rpm in my mind but that was for the 70 so 7700 on an old 62? not bad Cymaz, i had a look and found an old video, looked pretty monsterous! Link to comment Share on other sites More sharing options...
SR 71 Posted January 13, 2020 Share Posted January 13, 2020 I have just started a new build, a B36 Peacemaker 108" wingspan, i would like to power it with Laser engines, but i think 50s are the smallest, think it would be overkill with 6 of them ?? Tony Link to comment Share on other sites More sharing options...
Jon H Posted January 13, 2020 Author Share Posted January 13, 2020 Posted by SR 71 on 13/01/2020 10:42:59: I have just started a new build, a B36 Peacemaker 108" wingspan, i would like to power it with Laser engines, but i think 50s are the smallest, think it would be overkill with 6 of them ?? Tony Our smallest is a 70 now (the 50 was discontinued in 1986 i think) and we have a customer in the netherlands using 4 of them to power a 158 inch B17 so 6 in a 108 inch B36 will be a bit much. I also flew a 100'' Hercules on 4 ASP 30 4 strokes some time back and it was fine so if you wanted the full 6 engines then its likely you would need to go really small. Link to comment Share on other sites More sharing options...
SR 71 Posted January 13, 2020 Share Posted January 13, 2020 Ok Jon thanks, any ideas on the motors anybody, i really did not want to go electric as it dont cut it, i used to watch these fly over our village when i was 10 years old, the sound they made is something i cannot forget Link to comment Share on other sites More sharing options...
Don Fry Posted January 13, 2020 Share Posted January 13, 2020 Could you bear just awesome, 4 motors, 2 dummies. I know a set up Laser is easy to start, but, on a cold day, thats still going to cost you, first start of the day, 6 tanks to fill, twirl, twirl. 10 minutes? Respect for the ambition mind. Link to comment Share on other sites More sharing options...
SR 71 Posted January 14, 2020 Share Posted January 14, 2020 Thats the beauty of the hobby Don, the time spent filling and starting the six engines is all part of the excitement, not to mention running up the two EDF fans in the four jet engines So im looking for small four stroke engines, if anyone has any ideas Tony Link to comment Share on other sites More sharing options...
Maurice Dyer Posted January 14, 2020 Share Posted January 14, 2020 Posted by SR 71 on 14/01/2020 06:50:23: Thats the beauty of the hobby Don, the time spent filling and starting the six engines is all part of the excitement, not to mention running up the two EDF fans in the four jet engines So im looking for small four stroke engines, if anyone has any ideas Tony If you are rich enough:O.S 56 four stroke. Maurice Link to comment Share on other sites More sharing options...
Maurice Dyer Posted January 14, 2020 Share Posted January 14, 2020 Laser 70. I'm buying one, but a question first. Looking at the pictures on their web site, can the exhaust be rotated to exit down. Shown upright and the exhaust stub (manifold) looks pretty short ?? Maurice Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted January 14, 2020 Share Posted January 14, 2020 The laser exhaust on all models can be positioned pretty much any which way one wishes to (except towards the carb that happens to be just next door on the same plane) Link to comment Share on other sites More sharing options...
Jon H Posted January 14, 2020 Author Share Posted January 14, 2020 Posted by SR 71 on 14/01/2020 06:50:23: Thats the beauty of the hobby Don, the time spent filling and starting the six engines is all part of the excitement, not to mention running up the two EDF fans in the four jet engines So im looking for small four stroke engines, if anyone has any ideas Tony Hah! that would be sweet. One chap in europe has 12 engines (yes, 12) fitted to his big old flying boat. Its absolutely stunning Anyway, if you want all 6 and to use the EDF's as well then i think you will be going in search of 30's. I used a mix of ASP, SC and Magnum in my hercules as they were all the same. Impossible to get them running together mind you. I just set each one so it was half decent and then got on with it. Its that or build a bigger one for some 70's Maurice, the exhaust can point anywhere you like Link to comment Share on other sites More sharing options...
Recommended Posts