Kev Bamber Posted March 3, 2011 Share Posted March 3, 2011 How critical is the carb/tank position for the Laser engine in my Fokker DVii? With my engine correctly mounted, and the tank fully within the bulkhead, carb c/l is around 30mm above the tank c/l. I cannot position the tank to the recommended similar level as carb because unlike other engines the carb is at cylinder head level which would have my tank sticking well out if the fuselage! Quote Link to comment Share on other sites More sharing options...
steve 1 Posted March 3, 2011 Share Posted March 3, 2011 Hi Kev, I would say not a problem, I have a T28 with the carb about 25mm above tank and a spitfire with carb about 40mm below tank and a typhoon with carb about 70mm below tank.>> All laser’s and no problem with the running of any of them, that’s another good thing about laser engines.>> Steve >> Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 5, 2011 Share Posted March 5, 2011 Hello kev. I had a fokker Dvii a few years ago and retro fitted a laser 70 to it, the tank was in the designed position .As you say the carb is fitted to the head and I worried wether or not it was to high for the tank . no need to worry the lasers draw fuel really well . Once primed for starting it would run the tank dry no problem . E.D Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 5, 2011 Share Posted March 5, 2011 As I've said on a another thread recently most 4 strokes draw fuel well - better than 2 strokes in my experience. So tank a bit low is not generally a problem. But if the tank is a bit high then it can be a problem as they seem to like to syphon! BEB Quote Link to comment Share on other sites More sharing options...
Kev Bamber Posted March 6, 2011 Author Share Posted March 6, 2011 Thanks for your replies, they give me confidence that the installation will be okay. Kev. Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted January 8, 2012 Share Posted January 8, 2012 Hello Steve and others; I'm mounting a Laser 240 twin in a Great Planes YAk 54; It seems the tanks c/l will be about 50mm higher than the carbs centerline which should be ok, based on the posts above. However, how far can the tanks be from the carbs? I know the general principle is "as closed as possible" The challenge is: the tanks won't fit (without modifications) inside the engine box = this means a 15 centimetres or so distance to the carbs from where the tanks meet the bulkhead . Is this way too too far or worth trying and testing? I know Lasers draw fuel very well but I am lacking "a rule of thumb" on how well Lasers draw fuel when the nose is pointing up.. Any hints / comments from more experienced laser owners are wellcome and appreciated!! thanks, artto Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted January 8, 2012 Share Posted January 8, 2012 My flair d7 had a laser 80 with a 12 ounce tank, no problem with suction, one day the throttle servo became disconnected at about 3/4 throttle and 2 minutes into the flight. 20 odd minutes later the engine cut and I swapped the tank for an 8 ounce one. With regard to the distance that a laser will draw fuel, in modelflyer there was an article on fitting a petrol engine walbro carb that is used purely as a pump driven by the pulses from the crankcase, this was designed around a laser single cylinder either a 150 or 180. I can't comment on how it works for the laser but the conversion took me about 10 minutes and is fitted to an os 160 fx in an xtrawot I have which has yet to fly. The walbro carb definitely pumps glow fuel well when used with a 61 two stroke connected to the exhaust silencer pressurisation nipple. HTH. Quote Link to comment Share on other sites More sharing options...
steve 1 Posted January 8, 2012 Share Posted January 8, 2012 Hi Artto, I can't say that i've ever tried the tanks back that far (height not a problem) but if it was me i would give it a go getting the tanks as far forward as possible and use big bore pipe for the plumbing. Personally i think it will be ok but thats only my opinion not tried and tested. As a test how about setting it up on a test stand with the tank 50mm below the c/l and 150mm away from the engine and running it to see, that would give you the worst case scenario (inverted and push elevator). Or you could always give laser a call as there very helpful. HTH Steve Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted January 9, 2012 Share Posted January 9, 2012 Hi Steve and John Thanks for your help I guess I will test the set up; let's see then! I will post my experiences once something to report regards artto Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted January 10, 2012 Share Posted January 10, 2012 Hi Steve, I called Neil at Laser engines. He wasn't too concerned about the height of the tanks but he said the tanks mounted 150mm away from the carbs would never work. He recommended carrying out needed modifications to get the tanks closer to the carbs, less than 60mm or so. Alternatively a use of pump such as cline might be another solution. Any experiences on the cline system / Perry pump with Laser engines? Btw Neil was of great help and a very nice person! artto Quote Link to comment Share on other sites More sharing options...
steve 1 Posted January 10, 2012 Share Posted January 10, 2012 Hi Artto, As i said i have never tried the tanks so far away so i have learnt something as well, thank you. I have no experience with pumps of any kind at the moment so sorry i dont know myself but i'm sure someone on here has and will chime in soon. Laser do provide an excellent product and after sales, so much so that i have not bothered with any other make since trying one for my self. Steve Quote Link to comment Share on other sites More sharing options...
Graham Cramp Posted March 8, 2013 Share Posted March 8, 2013 Hi all, I've just bought a Laser 100 to fit into a Topflite P47, I've just offered it up to the fuselage and without any accurate measurements it looks like the carb will end up around 60mm below the tank centre line... Looks like some serious work to get the tank any lower because the wing will be in the way - does anyone think this will be a serious problem? Or does anyone have any ideas to line them up better? Thanks Graham Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted March 8, 2013 Share Posted March 8, 2013 Posted by Graham Cramp on 08/03/2013 04:34:04: Hi all, I've just bought a Laser 100 to fit into a Topflite P47, I've just offered it up to the fuselage and without any accurate measurements it looks like the carb will end up around 60mm below the tank centre line... Looks like some serious work to get the tank any lower because the wing will be in the way - does anyone think this will be a serious problem? Or does anyone have any ideas to line them up better? Thanks Graham Hello Graham (in case you notice a problem caused by the tank height after having actually flown the model) You might want to try the Cline regulator system to cure the tank height problem. I'm using them in conjunction with my Laser 240v. The Cline system is a demand-type regulator that gives the carb the amound of fuel the carb wants. So there isn't any fuel pressure against the HS needle. Further, the hydrostatic pressure remains the same in all circumstances. I got mine from: http://www.billsroom.com/pcfs/ Regards Artto Edited By Artto Ilmanen on 08/03/2013 06:43:12 Quote Link to comment Share on other sites More sharing options...
Graham Cramp Posted March 10, 2013 Share Posted March 10, 2013 That does sound interesting... I think I'm going to have a go at lowering the tank, I've got an idea of how to do it and still keep the strength up at the front. Although I'm not sure I'll be able to squeeze the 11oz tank I've got in without some serious surgery - still achievable though. The Laser website recommends a 9oz tank for the 100 engine. What sort of a flight time would be achievable with this (gentle sport pottering around)? This would be an easier fit, but I don't want to go for that at the expense of reasonable flight times. Any help appreciated Thanks Graham Quote Link to comment Share on other sites More sharing options...
Former Member Posted March 10, 2013 Share Posted March 10, 2013 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Graham Cramp Posted March 10, 2013 Share Posted March 10, 2013 OK, That definitely sounds preferable to the sort of surgery I had in mind. And if it's recommended by the man himself then it must be a good solution. Many thanks for your time, I'll do a bit of investigating... Graham Quote Link to comment Share on other sites More sharing options...
Former Member Posted March 10, 2013 Share Posted March 10, 2013 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted March 10, 2013 Share Posted March 10, 2013 Posted by Percy Verance on 10/03/2013 18:50:03: Hi again Graham With regard to Artto's suggestion. Using the Cline system would also be an excellent solution. However, Artto is using his Laser V twin, and that is probably why he's choosing to use the Cline regulator. The V twin is too smooth to produce the vibes required to operate a regulator such as the Perry VP20. In fact the info supplied with the VP20 specifically state it will be unsuitable for use with twin cylinder engines. Edited By Percy Verance on 10/03/2013 18:52:36 Edited By Percy Verance on 10/03/2013 18:56:58 Hi Percy Based on some other discussion in this site I was under the understanding the Perry VP-20 does not feature a regulator? I tried to check this in the Perry web site but I couldn't find any usefull info on the matter. However, you say you have been using the VP-20 so how's the thing is there a regulator in the VP-20 or not? (In your post you do refer to "..oscillating pump/regulator.." thanks, Artto Quote Link to comment Share on other sites More sharing options...
Former Member Posted March 11, 2013 Share Posted March 11, 2013 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Fredthepen Posted March 11, 2013 Share Posted March 11, 2013 Hi, would a header tank closr to the engine help? Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted March 12, 2013 Share Posted March 12, 2013 Posted by Percy Verance on 11/03/2013 13:21:52: Hi Artto The Perry VP20 has adjustable flow, using the large nut on the end, as do the other Perry pumps. I guess that in an installation such as Graham's, the facility to regulate the fuel flow rather than pump it would be of greater importance? Just as a point of interest, do take your pressure feed form your silencers or the crankcase? Hi Percy I take the pressure feed from the silencers, see my reply #66 in this thread for the pctures: http://www.rcmf.co.uk/4um/index.php/topic,87565.40.html Rgds Artto P.S. i got the hint to use the Clines in one conversation with Neil Tidey.. Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted July 6, 2013 Share Posted July 6, 2013 Hi Kev, I would say not a problem, I have a T28 with the carb about 25mm above tank and a spitfire with carb about 40mm below tank and a typhoon with carb about 70mm below tank.>> All laser’s and no problem with the running of any of them, that’s another good thing about laser engines.>> Steve >> Hi Steve I'v been running my Laser 240v with the Cline regulators but as I tested the engine without them, out of curiosity, I noticed it runs smoother without the Clines. So I'm converting my tank set-up and fly the model without the Clines. In my case (a GP Yak 54) the carbs are about 50mm below the tank centerline as the engine is inverted. How do you adjust the carb in the Typhoon? I'm just thinking that if you adjust it to max power on the ground what happens when you fly inverted or vertical? Won't it go lean? (I'm thinking that if I mounted my engine cylinders cylinders pointing up the adjustement of the carbs might be less fussy as when you adjust them to max power on the ground the engine would go rich due to the hydrostatic pressure change (if the tuning changes at all) when flying inverted. This is safer with respect of avoiding dead stick etc. ) I appreciate any comment Edited By Artto Ilmanen on 06/07/2013 14:52:48 Edited By Artto Ilmanen on 06/07/2013 14:54:28 Quote Link to comment Share on other sites More sharing options...
steve 1 Posted July 6, 2013 Share Posted July 6, 2013 Hi Arrto I have the bottom end just slightly rich and top end tune for max revs then back off a little as you would do normally, i have not experienced any problems so far, if when doing a loop if it drops a few revs at the top (tad lean) then i just richen a couple of notches on the top end but that is probably only twice a year (winter and summer). No difference inverted. I have loaded some photos for you so you can see my laser fitted and how much lower the carb is in relation to the tank. HTH Steve Quote Link to comment Share on other sites More sharing options...
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