Scott Edwards 2 Posted February 1, 2022 Share Posted February 1, 2022 On 26/01/2022 at 20:10, Jon - Laser Engines said: we actually have some spinner adaptors now that fit our sleeve nuts. I have extensions as well Oooooh !! Do they fit the 180 ? Link to comment Share on other sites More sharing options...
Jon H Posted February 1, 2022 Author Share Posted February 1, 2022 yep, got them for everything Link to comment Share on other sites More sharing options...
alan p Posted February 7, 2022 Share Posted February 7, 2022 HI JON Would a Laser 70 be suitable for a 55" span Spitfire(that has a recommended engine size of 52fs). Or will it be unsuitable, I prefer scale performance as opposed to tearing round the sky. Also what would be the minimum tank size. Link to comment Share on other sites More sharing options...
Jon H Posted February 7, 2022 Author Share Posted February 7, 2022 1 hour ago, alan p said: HI JON Would a Laser 70 be suitable for a 55" span Spitfire(that has a recommended engine size of 52fs). Or will it be unsuitable, I prefer scale performance as opposed to tearing round the sky. Also what would be the minimum tank size. You wont need the power, and i suspect the engine will be too heavy and too large physically. Tank placement may also be difficult in a model that size. Which model is it you are looking at? Link to comment Share on other sites More sharing options...
alan p Posted February 8, 2022 Share Posted February 8, 2022 Hi Jon It's a Warbird Replica Spitfire Mk1X. Thankyou for the advise. Link to comment Share on other sites More sharing options...
Jon H Posted February 8, 2022 Author Share Posted February 8, 2022 8 minutes ago, alan p said: Hi Jon It's a Warbird Replica Spitfire Mk1X. Thankyou for the advise. I thought it might be. You could try and wedge it in there, but a former clubmate had one and its not a big model so i would be concerned about the tank placement. What i suggest you do is grab the dimension drawing for the laser 70 off our website and print it off at the right scale. You can then lay it on the plans and see how things look. 1 Link to comment Share on other sites More sharing options...
David Hazell 1 Posted February 9, 2022 Share Posted February 9, 2022 Could be a _bit_ of a squeeze... Link to comment Share on other sites More sharing options...
Graham Davies 3 Posted February 9, 2022 Share Posted February 9, 2022 I think the biggest challenge will be the tank position. To get the top level with the carb, it will need to be rather flat! Link to comment Share on other sites More sharing options...
alan p Posted February 9, 2022 Share Posted February 9, 2022 Thankyou David /Graham vertical mounting would definitly be a problem with the tank. Will look whether rotating 30/45 degrees will provide any better, may interfere with the cosmetic appearance though. Got a case of Laser envy at the moment they are rather good? Link to comment Share on other sites More sharing options...
Graham Davies 3 Posted February 9, 2022 Share Posted February 9, 2022 I can understand that Alan! The original motors have a totally different carb configuration which makes inverted fitting/ tank position less of an issue. It may be that you save your laser for a different project (we all need plenty waiting in the wings!) as it may be a case of chasing diminishing returns. Link to comment Share on other sites More sharing options...
Chris Walby Posted February 9, 2022 Share Posted February 9, 2022 I tend to mount my Lasers horizontally as it make tank position easier, looks ok from the port side if scale or starboard for the Laser appreciation society guys! Plus IMO I find it a lot easier tuning a horizontal mounted engine as opposed to an inverted one (especially if its in a cowl). Link to comment Share on other sites More sharing options...
Jon H Posted February 9, 2022 Author Share Posted February 9, 2022 (edited) Its not as bad as i thought it might be. You could get it in there if you move the firewall, and modify the wing centre section so the tank can sit in the wing. Its still a quart in a pint pot situation but it might work ? If it did you would have no shortage of power that is for sure. Chris, a side mounted engine in a spitfire?! blasphemy! Edited February 9, 2022 by Jon - Laser Engines Link to comment Share on other sites More sharing options...
David Hazell 1 Posted February 9, 2022 Share Posted February 9, 2022 2 hours ago, alan p said: Thankyou David /Graham vertical mounting would definitly be a problem with the tank. Will look whether rotating 30/45 degrees will provide any better, may interfere with the cosmetic appearance though. Got a case of Laser envy at the moment they are rather good? The plan does show the engine mount canted at about 20 degrees - which indeed would lift the carb a bit and might even house the cylinder a bit better. Agreed the firewall would need fudging about, but I reckon it might just be doable. Whether it's the most ideal engine is another issue though?! Link to comment Share on other sites More sharing options...
Chris Walby Posted February 9, 2022 Share Posted February 9, 2022 1 hour ago, Jon - Laser Engines said: Chris, a side mounted engine in a spitfire?! blasphemy! IMHO, if its good enough for a P39 and a FW 190 then its good enough for a Spit, of course a completely different argument if it was a Hurricane ? 1 Link to comment Share on other sites More sharing options...
Martin McIntosh Posted February 9, 2022 Share Posted February 9, 2022 (edited) I would go for it, you will need the weight in the front anyway. Point the exhaust downwards though. Since the full size did not do outside loops the tank should be fine wherever you can get it in: Sullivans are quite shallow. I use a Laser 70 in a 57" Tiggy on a 14x5 and it is fine. You could also try a three blader which would cut down the power and look better. I have a TN 62" Spit. which now has a very powerful YS 63 but an 11 1/2x6 three blade tames it. Edited February 9, 2022 by Martin McIntosh Link to comment Share on other sites More sharing options...
Jon H Posted February 9, 2022 Author Share Posted February 9, 2022 49 minutes ago, Martin McIntosh said: Since the full size did not do outside loops the tank should be fine wherever you can get it in: If tank placement is poor a simple barrel roll will cause problems. Loops and half cuban's would be worse still so even scale spitfire flying will not be possible if the tank isnt in the right place. Its not just aerobatic models that will suffer. Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted February 9, 2022 Share Posted February 9, 2022 Can't you make a carburettor elbow extension to bring it up a bit ?. Link to comment Share on other sites More sharing options...
Jon H Posted February 9, 2022 Author Share Posted February 9, 2022 (edited) 8 minutes ago, Paul De Tourtoulon said: Can't you make a carburettor elbow extension to bring it up a bit ?. Then you suffer all of the performance and reliability penalties connected to that design. We have discussed doing it in the past, and it was tested, but it made the engines worse so we didnt see the point. Just lower the tank so its inline. Its not a massive job, especially on a kit build. Edited February 9, 2022 by Jon - Laser Engines Link to comment Share on other sites More sharing options...
Martin McIntosh Posted February 9, 2022 Share Posted February 9, 2022 I beg to disagree. My 72" Spits have the tanks completely above the carb with no problems at all, in fact if they were to go slightly rich in a loop it would not hurt. There is absolutely no way to get them lower in a Spit with an inverted Laser. Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted February 10, 2022 Share Posted February 10, 2022 14 hours ago, Martin McIntosh said: I beg to disagree. My 72" Spits have the tanks completely above the carb with no problems at all, in fact if they were to go slightly rich in a loop it would not hurt. There is absolutely no way to get them lower in a Spit with an inverted Laser. Tell us all about it, if I install a tank a bit high they all flood and I have to turn them upside down to empty them and eventually get them started,,,, My Spitfire has it's Enya .90 sidewinder, I want to fly not fiddle and keep screwing the prop back on after flipping it on a flooded backfire,,,? Link to comment Share on other sites More sharing options...
Chris Walby Posted February 10, 2022 Share Posted February 10, 2022 15 hours ago, Martin McIntosh said: I beg to disagree. My 72" Spits have the tanks completely above the carb with no problems at all, in fact if they were to go slightly rich in a loop it would not hurt. There is absolutely no way to get them lower in a Spit with an inverted Laser. Sorry as I really don't get this, Jon (Laser Engines) gives free advice based on experience and as the subject matter expert for Laser engines (does anyone on this planet know any more about the current range of Laser engines - NO). So if the advice is to line the carb up with the tank then that's the advice....if you deviate from the professional advice then you do so entirely at your own risk. If you want a sub optimal set up and performance then go ahead, but for me and especially with twins I want as many odds stacked in my favour as possible, just makes flying that more enjoyable known its less likely to dead stick on me. Shall we move on to castor oil and high nitro again...? 3 Link to comment Share on other sites More sharing options...
alan p Posted February 10, 2022 Share Posted February 10, 2022 Hi Chaps My original OP was a polite enquiry to Jon on a engines suitability for a specific model. His advise was given in the same manner. I appriciate all the advice from the formites who have the experience of such insulations. But would prefer it not to become a slanging match between various opinions. So in that light I would ask the moderator to close the thread. Link to comment Share on other sites More sharing options...
Jon H Posted February 10, 2022 Author Share Posted February 10, 2022 (edited) Im sorry Martin but your statements are incorrect. With the tank high needles are set very lean (in number of turns) to offset the assistance from gravity. If you do anything that results in the model being inverted the fuel tank drops substantially in relation to the engine so this gravitational assistance is lost. the lean setting on the needle means the engine is unable to draw fuel now gravity is against it. An acceleration change of nearly 20m/s^2 due to gravity inverting is simply too much for the engine to handle. Consequently it will run lean and either loose power, or stop. If it does keep running it will then go rich at the bottom of the loop due to the increased G force as you recover. It ends up being a dogs dinner with the engine running lean, then rich, then lean again. It wastes fuel, gives variation in performance, compromises reliability, etc. All of this is very simple physics and, to be honest, many of your models exhibit these problems. I have seen it with myself and while you may be satisfied with the level of performance you are getting it is not the level of performance you could achieve with the tanks positioned properly. When it comes to lowering the tank in a Spitfire, its absolutely possible. My Hurricane's are modified to allow the tank to sit in the wing and my 3 future Spitfire builds will be as well. The ugly mustang i am fixing will have its tank mounted low enough to suit the inline as well as all the other mods needed to suit the engine. We also have customers flying BT Typhoons with wing leading edges modified to suit and the nose on them is super short. The only models i have even known that absolutely cannot be modified to have a lower tank are things like tucano's and PC9's when the retracting nose wheel is right in the way. In these cases you would need to make your own tanks to sit either side of the leg, or just mount the engine on its side. So the ultimate conclusion is that any model can have the tank placed correctly if the required modifications are made. The amount of work required may be quite small, or substantial, but it can be done provided the carb is within the aircraft outline. Under slung external fuel tanks probably are not an option. I am not trying to throw you under the bus Martin but you are directly contradicting the recommendations of the manufacturer of the kit you are using while it exhibits many of the problems that cause said manufacturer to not recommend the very thing thing you are promoting. I make these recommendations on installation as they guarantee the operation of the engine in all models, under all circumstances, anywhere in the world on any fuel every day of the week. I cant recommend something that worked for one bloke in 2 models to only his satisfaction. Its why i dont recommend Steve Dunne's pressure isolated header tank setup. It works, i know it works, but the level of complexity and the skill required to make it work means its functionality is more down to how well its put together than its original design. If someone follows your advice, or Steve's, and their engine runs like a dog who do you think will get the phone call asking for help? Me. At the end of the day you have no responsibility for the advice you offer. If it all falls over and someone's model crashes as a result of their engine stopping at a critical moment there is no backlash on you and the person reading your forum post wont call you up to complain, they will call me to complain. I probably deal with at least 10 people a week having problems with engines due to tank placement and too many times i get the 'oh a bloke at the club/forum/youtube said it would be fine'. Its not fine, it will not work. Install the tank in line with the carb. I know some of you may feel i am having a personal dig at Martin here and that is not the case. I know you all try to offer well meaning advice to help other people out with their problems. Its why the forum exists after all, but, alas, some of it is wrong and when it comes to Laser engines and their installation the buck kinda stops with me. This is the 'official' Laser technical questions thread and consequently i get the last word as i am the only one officially representing the brand. So i will counter any posts that contradict our recommendations. I am not trying to name and shame or humiliate anyone, i just need to make sure anyone reading this thread see's the same consistent advice from the manufacturer of the engine they have. Advice that i know will remove all the guess work and make sure their engines perform as they were intended to. Also anyone who has always done things a certain way and been happy enough might find a whole new level of performance by following the recommendations i make. You dont know what you dont know at the end of the day and all i am trying to do is make sure everyone has their engine run at its best. This even applies to other brands as OS, saito and ASP engines all perform way better on the right fuel, tuned correctly with the tank in the right place. Just get the basics right and the rest becomes so much easier. If you feel hard done by Martin give me a call and we can discuss it. Edited February 10, 2022 by Jon - Laser Engines 2 1 Link to comment Share on other sites More sharing options...
Jon H Posted February 10, 2022 Author Share Posted February 10, 2022 6 minutes ago, alan p said: Hi Chaps My original OP was a polite enquiry to Jon on a engines suitability for a specific model. His advise was given in the same manner. I appriciate all the advice from the formites who have the experience of such insulations. But would prefer it not to become a slanging match between various opinions. So in that light I would ask the moderator to close the thread. I appreciate the sentiment Alan but this is an old thread with loads of good info on it. I would rather it wasnt closed over such a minor issue. Hopefully my above post covers things off and anyone who wants to is free to contact me directly should they wish to discuss the matter further. Link to comment Share on other sites More sharing options...
alan p Posted February 10, 2022 Share Posted February 10, 2022 Sorry Jon I had forgotten the subject was within the main thread, yes I would not want all the other good info lost.? Link to comment Share on other sites More sharing options...
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