Jon H Posted November 23, 2015 Author Share Posted November 23, 2015 At this size i dont think anything other than petrol would sell so yes that would be the aim. Quote Link to comment Share on other sites More sharing options...
flight1 Posted November 23, 2015 Share Posted November 23, 2015 yes a range of long stroke v petrols for turning high pitch at low rpm for a lovely scale effect from 25cc 35cc 65cc would be nice and tempting for a lot With cdi ignition weight and interference is not a big issue, but close attention to the exhaust with a nice tone and to be effective is a major factor and must be give serious consideration for any new engine. The 3D type blip throttlers are well catered for in the Chainsaw market Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted November 23, 2015 Share Posted November 23, 2015 Posted by Jon Harper on 23/11/2015 10:16:14: Hi Flight Your comments about the lubrication properties of petrol are correct in a two stroke where the fuel flows through the crankcase. In a 4 stroke however there is only ever oil in the crankcase as all the fuel (methanol or petrol) should have been burnt in the combustion chamber. As a result the lubricity of the fuel is more or less irrelevant in the case of a 4 stroke. We have also been asked for single carb twins for many years but the problem is reliability. With a single carb you cant get the optimum mixture to each cylinder so one will always be less than perfect and usually stop. I have 3 single carb multi cylinder engines and all of them need on board glow systems to keep their cylinders lit where as the twin carb lasers need so such babysitting. Tuning if the twin carbs is a very simple procedure and so there is nothing desirable about a single carb glow engine. A petrol engine, with its cdi unit looking after the cylinders could be tried with a single carb but performance may be compromised. Jon, I know this is a bit off-topic but still: Why don't you publish your great "how to properly tune a Laser V-twin" video here: Here's the thing: You already did a great video on Laser 240v which is available at RCU "Club Laser thread". By watching that video 98% of the requests for a single carb solution disappear.. seeing is believing! -Artto Edited By Steve Hargreaves - Moderator on 23/11/2015 17:40:30 Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 23, 2015 Author Share Posted November 23, 2015 Sounds fair. This is a Laser 240v getting its factory test run on my nasty old test stand (now replaced). The engine had never run prior to this video being taken. From this you can clearly see how easy it is to tune the twin carbs. I re tweaked the right hand cylinder as i noticed something i didnt like but it was just the ring needed more running. I gave it a second go after it cooled and it was perfect. Enjoy: Edited By Jon Harper on 23/11/2015 17:06:13 Edited By Steve Hargreaves - Moderator on 23/11/2015 17:38:15 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted November 23, 2015 Share Posted November 23, 2015 Useful info just here on how to embed YouTube videos folks.... Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted November 23, 2015 Share Posted November 23, 2015 Interesting stuff Jon.... What are you actually looking &/or listening for as you tune each needle valve? Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 23, 2015 Author Share Posted November 23, 2015 I tried several times to get that stupid thing to embed. in the end I settled for the link! Anyway you basically lean off each cylinder until it dies and then go back a bit until its running again. Exactly the same as with a single. At 2.18 and 2.30 you can hear the revs drop and then come back as I just tweak the needle back by 1/8 turn. Edited By Jon Harper on 23/11/2015 23:19:07 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted November 24, 2015 Share Posted November 24, 2015 OK Thanks Jon.....I was wondering how obvious it would be when just one cylinder "peaks"...... Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 24, 2015 Author Share Posted November 24, 2015 No worries. people do get freaked out by twin carbs sometimes but they are just so much easier than single carbs. Clearly engines more than 2 cylinders could be an issue with multiple carbs, but if they are petrol they will be better able to handle it. Also things can be done to even out the flow to all cylinders and this will get around the problem nicely. Quote Link to comment Share on other sites More sharing options...
Gordon Whitehead 1 Posted November 24, 2015 Share Posted November 24, 2015 I think the 240v in this video looks dead cool with its black anodizing. Apparently this was an experiment and I was lucky that at the time I ordered my 240v, Jon had enough parts lying around to make mine the same. It looks gorgeous inside a radial cowl, and apart from Jon's 240 in the video is probably unique. I wonder if there's any enthusiasm amongst Laser lovers for this variation to be an option on a new engine (at extra cost as necessary)? Just a thought Gordon Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 24, 2015 Author Share Posted November 24, 2015 there are a few 'black edition' engines around but not many. I would love to do more of them like this as they look dead cool! Your message is also timely as i keep forgetting to mention that your 240 is fixed and ready to come back to you if you want it. Quote Link to comment Share on other sites More sharing options...
kevin b Posted November 24, 2015 Share Posted November 24, 2015 Posted by Jon Harper on 24/11/2015 20:32:06: there are a few 'black edition' engines around but not many. I would love to do more of them like this as they look dead cool! Your message is also timely as i keep forgetting to mention that your 240 is fixed and ready to come back to you if you want it. If he doesn't I will take it out of your way. Quote Link to comment Share on other sites More sharing options...
David Ovenden Posted November 25, 2015 Share Posted November 25, 2015 Jon This thread has had an interesting outcome. Having never owned a Laser engine (I have Saitos, OS, and Enya four strokes) I have now purchased a Laser 200v twin. It has never been used and is therefore as new, but is a 1999 model! It is going in a Hangar 9 Beaver 110 inch version. Your video of setting up the 240v was therefore very timely. One issue seems to be the short threaded section on the crankshaft. My 18x8 prop seems to have thick hub and the crankshaft is too short. Is this a feature of the older models? Do later versions have a longer crankshaft along with a metric thread? Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted November 26, 2015 Share Posted November 26, 2015 Posted by David Ovenden on 25/11/2015 22:05:09: Jon This thread has had an interesting outcome. Having never owned a Laser engine (I have Saitos, OS, and Enya four strokes) I have now purchased a Laser 200v twin. It has never been used and is therefore as new, but is a 1999 model! It is going in a Hangar 9 Beaver 110 inch version. Your video of setting up the 240v was therefore very timely. One issue seems to be the short threaded section on the crankshaft. My 18x8 prop seems to have thick hub and the crankshaft is too short. Is this a feature of the older models? Do later versions have a longer crankshaft along with a metric thread? David, First, you do not need double nut on Lasers. They don't kick back (I have a 240v and a 300v). So any conventional spinner nut is ok if the prop hub is not too thick so there is enough thread for the nut. In case the hub is too thick, then, you are supposed to use a sleeve nut. They are inexpensive, give a call to Laser engines to get one. Here is a video on Jon's 240v with a prop secured by sleeve nut: https://www.youtube.com/watch?v=mS-F96pVcUk -Artto Quote Link to comment Share on other sites More sharing options...
flight1 Posted November 26, 2015 Share Posted November 26, 2015 I have a 200v and the prop hase never come off or kicked back. I use the sleeve nut which came with the engine . As the post above says you can get it from laser engines for not much. Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 26, 2015 Author Share Posted November 26, 2015 Hi David, we can supply the required 3/8 sleeve nut and washer for £8.50 including the shipping. All you need to do is drill/ream your prop to 13mm. As the other guys have said, Laser engines don't require a double nut as they never throw props. In truth, most modern 4 strokes are nowhere near as aggressive as the original ones used to be. I remember my dad spending fortunes on new prop nuts for his OS 48 surpass. That used to throw props all the time! Quote Link to comment Share on other sites More sharing options...
Gordon Whitehead 1 Posted November 26, 2015 Share Posted November 26, 2015 Posted by kevin b on 24/11/2015 20:36:34: If he doesn't I will take it out of your way. Sorry Kevin - it's coming back home Gordon Quote Link to comment Share on other sites More sharing options...
Hannes Koekemoer Posted November 26, 2015 Share Posted November 26, 2015 Hello all I am a 16-year old from South Africa. I have just found this thread and find this discussion very interesting. The petrol engines appeal greatly to me because of the prospect of having to drive 100 miles for a decent hobby shop to buy very expensive (imported) glow fuel. The larger problem for me though, is the initial cost of getting into petrol or glow. I could only afford to build 2 balsawood electric models from plans up until now over a 2 year span, no ARTF's for me! (I rather dislike them). It almost saddens me to hear about the decreasing interest in petrol or glow powered models, because I love the sheer presence of them and all of the internally moving parts working perfectly to deliver useful power brings joy to me. I would however not be able to afford such a model anytime soon, so I have started to get into machining to try and build my own engines. At present I have 2 working stirling engines and 3 steam engine and am slowly working my way up to an ic-engine. I realise that I am probably one of the few of my type (future 'rivet counters' in the younger generation, but I will always go against the flow and continue my perfectionist ways. I just thought it would be good to know that petrol and glow engines and traditional balsa models still appeal to at least some of us young modellers. Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 27, 2015 Author Share Posted November 27, 2015 Hi Hannes I dont think you are alone in your love of mechanical powerplants. There are many of us! Best of luck with your future projects. Regarding the original purpose of the thread i think we are getting near calling it a day? Quote Link to comment Share on other sites More sharing options...
MattyB Posted November 27, 2015 Share Posted November 27, 2015 Yeah, I guess so. One thing is for certain - there remains plenty of enthusiasm for the Laser brand and values, so if you can select the right products (and ignore those asking for a 20cc V10... ) I think you will have a lot of success. Personally I'd be happy with just the 180 petrol sometime before the spring! Edited By MattyB on 27/11/2015 13:05:54 Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 27, 2015 Author Share Posted November 27, 2015 Before the spring might be a challenge as i have a new avenue to research following my recent development. That said, there is nothing to stop us introducing an updated version in the future. Either way, my testing will continue through the winter and i hope i can get my other 3 pre production engines together and in the air. Currently i need to really test how well the engines work in a cowling as the first prototype really did not like being i the cowling of my Stampe and i need to test to see if my new modifications are sucessful in fixing the problem Quote Link to comment Share on other sites More sharing options...
Derek Stevenson Posted November 28, 2015 Share Posted November 28, 2015 I think this is a great thread when someone with Jon's knowledge answer questions on his engines and show us some of the difficulties in doing certain things. By the way did I miss Laser on Black Friday? I raided my piggy bank to buy one when the price was down, hope I didn't miss it 😠 Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 30, 2015 Author Share Posted November 30, 2015 Sorry Derek, in the interest of customer safety we didn't do any black Friday deals as we didn't want you guys tripping over eachother and falling into a lathe as you all piled through the door. While it would have been amusing to watch people fighting to the death just to get their hands on the pile of prop nuts and exhausts with a 50p discount we thought that all the bones jammed in the swarf conveyers would hamper production. Also, we aren't American And anyway, our engine prices are very favourable vs our Japanese friends, not to mention our spares prices! Quote Link to comment Share on other sites More sharing options...
Derek Stevenson Posted November 30, 2015 Share Posted November 30, 2015 Top class engines and a sense of humour, couldn't beat that! (Looks like I'll have to wait to the traditional British Januaty sales) 😠 Quote Link to comment Share on other sites More sharing options...
Former Member Posted November 30, 2015 Share Posted November 30, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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