Jon H Posted April 3, 2020 Author Share Posted April 3, 2020 Posted by Dirk Witvrouwen 1 on 03/04/2020 09:36:16: And Jon, don't forget a stylish back-mouted integrated starter for the radial 😁 No room for that, the supercharger and fuel pump are in the way. Its dead weight anyway Link to comment Share on other sites More sharing options...
Nigel R Posted April 3, 2020 Share Posted April 3, 2020 Posted by Jon - Laser Engines on 03/04/2020 10:39:13: fuel pump sounded suspiciously like you said "fuel pump" there Jon!? Link to comment Share on other sites More sharing options...
Jon H Posted April 3, 2020 Author Share Posted April 3, 2020 yea the pump will need to sit on the back of the case in a petrol version. I would be happy with a glow prototype for now though. Link to comment Share on other sites More sharing options...
Chris Walby Posted April 3, 2020 Share Posted April 3, 2020 Well a reduction drive would get my vote as the future will hold only more noise restrictions. A radial you say, very nice. Mind you getting a numpty like me to get one cylinder set up correctly is a challenge, a twin an outside chance. Now a radial it would best be to fit anti-tamper on all the carb screws or make every owner attend an anti-numpty training class. Then again a nice inline twin for those long nose warbirds is an idea. Link to comment Share on other sites More sharing options...
Andy Shailer Posted April 3, 2020 Share Posted April 3, 2020 Hi all, can someone explain and show a picture of the fuel tank set up please for a laser 150, Ive never set one up before, on other engines I always used 3 vents, one to the carb, one to exhaust and the 3rd being the filler, do I simply block the exhaust line, sorry if this is a daft question. Thankyou in advance. Andy P.S Im only stating a 150 as thats what Im going to be using, any size laser tank set info will be grateful Link to comment Share on other sites More sharing options...
Keith England 1 Posted April 3, 2020 Share Posted April 3, 2020 Posted by Jon - Laser Engines on 03/04/2020 08:27:33: I also think one of the first things i would do is make a reduction drive. Get propeller rpm down for much reduced noise. I already have the design done. It would fit our 100, 120, 150,155,160v, 200v, 240v and 300v with only one component change needed per engine and would allow a 200v to swing something like 22x14 3 blade or 24x14 2 blade at a gentle 4400rpm on the prop. Loads of thrust, nice and quiet. i take it the component would be the front crankcase and, presumably this would (or at least could) move the prop shaft higher on the engine (or lower if inverted) which would have the added benefit of moving the carb and cylinder head nearer the centreline too. If so it sounds like a win on a number of fronts. Link to comment Share on other sites More sharing options...
Jon H Posted April 3, 2020 Author Share Posted April 3, 2020 Posted by Andy Shailer on 03/04/2020 11:39:15: Hi all, can someone explain and show a picture of the fuel tank set up please for a laser 150, Ive never set one up before, on other engines I always used 3 vents, one to the carb, one to exhaust and the 3rd being the filler, do I simply block the exhaust line, sorry if this is a daft question. Thankyou in advance. Andy P.S Im only stating a 150 as thats what Im going to be using, any size laser tank set info will be grateful set it up exactly as you would with an engine that uses exhaust pressure but instead of having the pressure pipe connect to the exhaust have it connect to a small brass tube that to glue in the cowl somewhere. The tube needs to point forward so that the prop slipstream provides a slight pressure into the tank. There are no shortage of ways to position the tube but i have pictured some options below. Link to comment Share on other sites More sharing options...
Jon H Posted April 3, 2020 Author Share Posted April 3, 2020 Keith, yep, it would be a whole new front end. Link to comment Share on other sites More sharing options...
Phil Francis Posted April 4, 2020 Share Posted April 4, 2020 Could I run a 15 x 10 three blade prop on a 200V? Struggling for ground clearance on a Topflite Cessna 182. TIA Phil Link to comment Share on other sites More sharing options...
Jon H Posted April 4, 2020 Author Share Posted April 4, 2020 Probably but i dont think it will fly very well. When you say you are struggling with clearance, are you chipping props all the time or just concerned you might? Link to comment Share on other sites More sharing options...
Phil Francis Posted April 4, 2020 Share Posted April 4, 2020 Not flown it yet Jon, just concerned as with a 17” prop I have about 3/4” clearance. Phil Link to comment Share on other sites More sharing options...
Andy Shailer Posted April 4, 2020 Share Posted April 4, 2020 Thank you for the info Jon. Andy Link to comment Share on other sites More sharing options...
Jon H Posted April 5, 2020 Author Share Posted April 5, 2020 Posted by Phil Francis on 04/04/2020 20:16:16: Not flown it yet Jon, just concerned as with a 17” prop I have about 3/4” clearance. Phil As long as you dont land on the nose wheel it should be fine. Give it a good old flare before touchdown. Takeoff wont be a big issue either, just hold the elevator hard back Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 5, 2020 Share Posted April 5, 2020 Running a 15 x 10 3 blade through this program, gives 8.3 kg thrust at 7,000 rpm a 2 blade 17 x 10 would give 10.6 kg at similar revs (but need more power). As the model quoted weight is 5.2 to 6.7kg and it's recommended engine is a 120 FS with a 14 x 8 it should fly OK on the 3 blade, just won't punch out of the 3D prop hang quite as well. BTW friend has a similar sized Cessna (Fiberglass fuselage) which is quite heavy, flies it on an ASP 120 FS, flys ok, but it wouldn't want anything less. Link to comment Share on other sites More sharing options...
David Davis Posted April 5, 2020 Share Posted April 5, 2020 I am building a Big Guff, an eight foot wingspan vintage model and one of the first model aeroplanes to be designed specifically for radio control. It will be powered by a Laser 70. Picture below of its fuselage and tailplane at a static exhibition which we held last month before the lockdown. A Canadian called Charlie Chomos has built one powered by an early OS 60 FS, the type with the exposed valve gear. These were not very powerful engines but Charlie's turns a 16x4 propeller. The maximum size prop recommended for a Laser 70 is a 14x4 or 14x5. Is a 16x4 too big for it? PS. My Big Guff will not look anything like as good as Charlies! Link to comment Share on other sites More sharing options...
Phil Francis Posted April 5, 2020 Share Posted April 5, 2020 Jon, Frank, thanks for your feedback. Phil Link to comment Share on other sites More sharing options...
Jon H Posted April 5, 2020 Author Share Posted April 5, 2020 Posted by Frank Skilbeck on 05/04/2020 08:25:16: Running a 15 x 10 3 blade through this program, gives 8.3 kg thrust at 7,000 rpm a 2 blade 17 x 10 would give 10.6 kg at similar revs (but need more power). As the model quoted weight is 5.2 to 6.7kg and it's recommended engine is a 120 FS with a 14 x 8 it should fly OK on the 3 blade, just won't punch out of the 3D prop hang quite as well. BTW friend has a similar sized Cessna (Fiberglass fuselage) which is quite heavy, flies it on an ASP 120 FS, flys ok, but it wouldn't want anything less. On a 15x10 a laser 200 will rev over 8000 i suspect and that could be a touch noisy with 3 blades. a 17x8 3 blade looks like its going to do low 7000's and that is a bit more like it. DD, it will be fine. I use a 15x5 turnigy wooden prop on my saito 45. Does 6000rpm flat out and will only run at full power for about 12 seconds before it overheats and begins to knock. As it only takes 8 seconds at full power to takeoff its all good! As long as i/you dont hammer the engine at high power it wont over heat, wont knock, and wont care about the overload prop Link to comment Share on other sites More sharing options...
David Davis Posted April 5, 2020 Share Posted April 5, 2020 Thanks Jon. Link to comment Share on other sites More sharing options...
Former Member Posted April 5, 2020 Share Posted April 5, 2020 [This posting has been removed] Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted April 5, 2020 Share Posted April 5, 2020 If I might make a suggestion... It sounds like the camshaft has seized into the outer bearing (the end float being until the cam gear hits the outer follower) so if you can get the cam followers to drop out then you should be able to remove the cover complete with the camshaft. If you haven't already done so, remove the cylinder head and pushrods and hopefully knocking the inverted crankcase on a block of wood will allow the followers to float free of the camshaft. A strong magnet might help to get them moving if they're sticking but it's the outer one that is important to move out of the way. You will not actually need to completely remove them - if the heads are level with casing there's more than enough clearance. If it's seized as I suspect then it may well be caused by rusting in the bottom end so a complete stripdown will make things easier and you'll probably need to do it anyway. Edited By Martin Harris on 05/04/2020 12:56:06 Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 5, 2020 Share Posted April 5, 2020 Posted by David Davis on 05/04/2020 11:56:05: Thanks Jon. If it helps, I'm flying a BB Majestic Major with an old Laser 62 and 15 x 4 prop, engine runs really well and it's a great match for the airframe. Link to comment Share on other sites More sharing options...
Former Member Posted April 5, 2020 Share Posted April 5, 2020 [This posting has been removed] Link to comment Share on other sites More sharing options...
Jon H Posted April 5, 2020 Author Share Posted April 5, 2020 If all else fails on the TT54 drill a hole in the middle of the other side of the cam chest and use a punch to get the camshaft out. As martin suggests, make sure the cam followers are out of the way first! Link to comment Share on other sites More sharing options...
Bruce Collinson Posted April 5, 2020 Share Posted April 5, 2020 I’d just like to say, taking advantage of a decent day, I ran up one of a pair of Laser 100s which I bought from a chap in Norway a couple of years ago NIB. He’d had them for several years, I recall. Started instantly, consumed an entire tankful without missing a beat. To be fair, so did a new Saito 100 although it’s more hesitant at the bottom end but no needle-fiddling just yet. BTC Link to comment Share on other sites More sharing options...
Former Member Posted April 5, 2020 Share Posted April 5, 2020 [This posting has been removed] Link to comment Share on other sites More sharing options...
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