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Laser Engines - Technical questions

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Jon - Laser Engines01/09/2020 22:02:08
5632 forum posts
271 photos

no idea. if it was for after run oil it was, like after run, a bit of a waste of time. Unless you brim the crankcase, really fill it up and get all the air out and then drain it adding after run does little to nothing. Even if you do flood the case, if the oil you use is not able to blend with the fuel/oil you use then again, its not helping you very much

Richard Harris01/09/2020 22:18:39
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2213 forum posts
2044 photos

Thanks for the info Jon and all, I've passed it onto my friend.

Rich

Martin Arnold 103/09/2020 17:56:12
34 forum posts
5 photos
Posted by Jon - Laser Engines on 01/09/2020 22:02:08:

no idea. if it was for after run oil it was, like after run, a bit of a waste of time. Unless you brim the crankcase, really fill it up and get all the air out and then drain it adding after run does little to nothing. Even if you do flood the case, if the oil you use is not able to blend with the fuel/oil you use then again, its not helping you very much

Totally agree with you Jon on the "ARO" as some people call it, they seem to go mad with pages of posts on another forum about the stuff !!

Gave up trying to use it years ago on my four strokes, the bearings still will rust as you say, think it just makes people feel better pumping some oil in the crankcase !!

Daniele deg03/09/2020 18:07:33
1 forum posts

Jon,

your tec tips are very instructive, I'd like to make some questions of general interest (sorry if I missed in the previus posts):

fuel: I'm using Motul micro 18% and 5% nitro on my saito 180, in an old post you say it's safe to run with 10% oil an 5% nitro, this is true for your Lasers or can be done also with others?

spark ignition: a spark ignition (alcohol) can produce better results in term of fuel consumption and power? I'ts a wast of time?

Corrosion: spray gun oil through the vent nipple could be an option for buried cowl engines, with little fly time (10 fly per year ex.).

Laser 300V: I hope you can restart the production of the twins, before the brexit will be complete?laugh (I live in Italy).

Thanks again for this precious support to the rc community,

cheers

Daniele

Jon - Laser Engines03/09/2020 19:05:46
5632 forum posts
271 photos

Yep, its another one in the modelling folk lore book in my view. You will stand a much better chance of preventing rust if you choose the right fuel, and then take the time to tune the engine properly. For some reason everyone burbles their engines round half a turn too rich complaining about high fuel consumption, cost, mess, rust, and reliability problems. All the while the flee to petrol and electric to rid themselves of the problems of a glow engine.

Little do they realise that actually, if they tuned it right and used a fuel than was less than 20% slime most of their problems would go away instantly. But nooooo, you cant run an engine 'lean' (ie, tuned for peak performance) as it will overheat! ok..fit the cowl properly and baffle it to direct the air..you know, make an effort?

Nope, that is all way too much like hard work. Lets just complain about stuff on forums instead

Sigh.

kevin b03/09/2020 19:20:31
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1935 forum posts
152 photos

Hey folks, Jon had a rant !

Maybe it was caused by the stress of working late nights on multi-cylinder engines and gearboxes ?

wink 2

Martin Arnold 103/09/2020 19:22:20
34 forum posts
5 photos

Yep Jon with you again !! I always tune mine to the max..... Non of this a few clicks rich for me, as you say the motor is not giving it's best set like that.

Been running all my four strokes as above apart from YS on MT Dynaglo 5% for years with a total oil content of 10% (8% EDL 2% castor), with no ill effects and you get a 85% methanol content, which is after all is the fuel !!

Edited By Martin Arnold 1 on 03/09/2020 19:23:48

Edited By Martin Arnold 1 on 03/09/2020 19:24:45

Martin McIntosh03/09/2020 19:48:23
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3582 forum posts
1233 photos

Is after run mineral or vegetable? Tried the stuff once and it took me ages to start the motor again. I once bought a s/h YS and the guy stated that it had been treated with after run which if it was mineral would have dissolved the silicone regulator.

I have not as yet found a solution to rusted bearings on a laid up engine.

Jon - Laser Engines03/09/2020 21:06:45
5632 forum posts
271 photos
Posted by Martin Arnold 1 on 03/09/2020 19:22:20:

MT Dynaglo 5% for years with a total oil content of 10% (8% EDL 2% castor), with no ill effects and you get a 85% methanol content, which is after all is the fuel !!

ditch the 2% castor and its a winner

Jon - Laser Engines03/09/2020 21:09:29
5632 forum posts
271 photos
Posted by Martin McIntosh on 03/09/2020 19:48:23:

Is after run mineral or vegetable? Tried the stuff once and it took me ages to start the motor again. I once bought a s/h YS and the guy stated that it had been treated with after run which if it was mineral would have dissolved the silicone regulator.

I have not as yet found a solution to rusted bearings on a laid up engine.

I tend to give any engine going into storage a good battering on the bench. First i blast it with the hose to clean it off, then fire it up. Small prop, loads of revs and get it as hot as i can. All the needles get reset and after a good thrashing i pinch the fuel off and turn it to TDC. Once cool enough i wrap it in a plastic bag and it then lives in a box under the bed. As yet i have not had engine rust up on me even after 5 or more years of snoozing.

tigerman15/09/2020 16:33:37
237 forum posts
1 photos

I have Seagull Gypsy Moth power by a Laser 80 I have a APC 14X7 prop on it but want to go for a more scale look and fit a wooden prop .I can only find a 14X6 wooden prop which I think will be fine but just wonder if I would notice any difference in the flying going from a 14X7 to a 14X6 prop .Any with a technical brain out there explain to me what the difference ,if any there would be flying a 14X7 prop to a 14X6 prop

Martin McIntosh15/09/2020 18:17:32
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3582 forum posts
1233 photos

My Super Aeromaster with a Laser 80 had a 14x7 APC but have just changed to a Falcon wood 15x6 in an attempt to get a better climb. Not bothered to measure the revs but the more efficient type of prop seems to overload it so I may well try a 14x6 wood if I can get one. Yours being a much slower model should be fine. You would get less speed and more pull.

tigerman16/09/2020 15:19:00
237 forum posts
1 photos

Martin I brought my 14X6 wooden Prop from " The Prop Guy " .It is £10.60 + £8 postage but the prop is a really good quality prop

Nick Somerville16/09/2020 15:50:28
149 forum posts
87 photos

Props definitely not all the same! I had a Aerostar 18x8 in my Extra 330sc on a Laser 180 and changed to a Menz of the same size and pitch. Quieter and a tad more pull going vertical. Today I changed the Smart 20x6 on my Stampe, also Laser 180, to a Menz 20x6 today and performance was hugely improved. On the Stampe I had started off with a 18x8 as the engine was new but changed to the Smart prop as I had bought it cheap. It is a lot clumsier looking that the Menz and it is now just going to be an emergency spare. Looping with the Smart was always a bit of an effort requiring a paced entry, whilst the Menz You can be pootling along at half throttle and go straight into a loop opening up as you start the climb.

Robert Welford16/09/2020 16:16:25
225 forum posts
4 photos

Propeller choice appears a little ad hoc / experimental at times.

I have a Graupner Taxi 2400 (2.4m high wing) powered by 3W 28i. Prop used Biela 19 x 8 and is/was a good match - noise/climb/speed.

I transferred the 3W 28i with the Biela 19 x 8 into an Acro Wot XL and it exhibited lacklustre performance. I changed the prop to a Mejzlik 18 x 11, which I thought would be too much and model came a live - unlimited vertical, reasonable noise level etc.

Wednesday evening this week I flew my CARF Extra 2.3m (3W 55 Xi) with Biela 23 x 8. Great all round performance, but sounds like a Harvard at times. As an experiment I changed the prop to a Mejzlik 23 x 8 and the performance was not as good - the vertical was reduced.

The trial and error approach works well for a 10cc glow models as props of this size are affordable. However, propeller experimentation gets a bit expensive for 30cc and above engines.

Edited By Robert Welford on 16/09/2020 16:22:40

Edited By Robert Welford on 16/09/2020 16:23:05

Robert Welford16/09/2020 16:30:01
225 forum posts
4 photos
Posted by Nick Somerville on 16/09/2020 15:50:32:

Props definitely not all the same! I had a Aerostar 18x8 in my Extra 330sc on a Laser 180 and changed to a Menz of the same size and pitch. Quieter and a tad more pull going vertical. Today I changed the Smart 20x6 on my Stampe, also Laser 180, to a Menz 20x6 today and performance was hugely improved. On the Stampe I had started off with a 18x8 as the engine was new but changed to the Smart prop as I had bought it cheap. It is a lot clumsier looking that the Menz and it is now just going to be an emergency spare. Looping with the Smart was always a bit of an effort requiring a paced entry, whilst the Menz You can be pootling along at half throttle and go straight into a loop opening up as you start the climb.

What APC propellers suit a Laser 180? I am re-engineing a 2m aerobatic model with a Laser 180. It is currently powered by a YS 160 DZ turning an APC 17 x 12. I am thinking that an APC 17 x 10 might work - any thoughts? Ground clearance is a bit tight for an 18 x 8.

Edited By Robert Welford on 16/09/2020 16:30:46

Jon - Laser Engines16/09/2020 17:14:02
5632 forum posts
271 photos

Tigerman - 15x6 wood will be ok. I used one on my 80 in my hurricane and it was ok. In the end i broke it, and the 14x7 apc suited the hurricane better, but the moth is a different animal.

As for props, they are single most neglected thing when it comes to tuning the performance of a model. Robert's point about the cost of testing new props on big engines is totally valid though and its why i have generally recommended the menz range over the years as i have used them myself and found them to work well. The price is also not too bad.

Im sure biela props are good, but i cant be spending 60 quid each time to test one and find i need another size.

As for the 180 in the pattern ship, as we discussed at the time its a bit of a fringe use case for the 180 so i dont really have any information on how it will perform. You can always try the 17x12 as you already have it. I suggest running something with a lighter load first though just to give it some run in time at higher rpm

Martin McIntosh16/09/2020 18:59:56
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3582 forum posts
1233 photos

I now have a Falcon 20x6 on my Stampe which I flew again yesterday. Loops are certainly better than the original 18x8 but the slower speed seems to upset the rolls. I would like to try a Falcon 14x6 on the 80 but 8 quid postage for one prop is a bit OTT. My newer Spit re engined to a 155 with a G-Sonic 18x8 is a perfect match.

Manish Chandrayan20/09/2020 21:30:41
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652 forum posts
74 photos

Jon

Would you recommend use of this lubricant from Motul?

Motul Micro

Anyone else have any experience with this lube ? Motul sales claims it for model engine use

Jon - Laser Engines21/09/2020 08:12:48
5632 forum posts
271 photos

Never tested it so cant say. It will probably be ok, but who knows?

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