New Laser engines. What do you want?

[Manish Chandrayan]

Jon if you want the engine tested in hot, humid and dusty conditions where no special oils are used (we use Castrol 2T for scooter etc or equivalent) I can volunteer to test it in India 😀

Edited By Manish Chandrayan on 05/04/2017 18:44:58

[Jon H]

Chris you could be on to something with sabotage

Manish, thanks for the offer but we will keep it local as its far easier to deal with any issues we may encounter and if it came down to it I could even visit the person and see for myself

[Jeremy Scott-hake]

Hi I have got just what I want from Laser engines!

A big thank you to Jon for building this beauty! the Black edition 200V twin.

[Alan Hilton]

Hi Jon

How much extra for the 360 in black?

Alan

[Jon H]

I have decided i dont like the black engines any more. They look so nice and i want to keep them for myself. Sending them to customers is like torture, especially when they then taunt me with photos :P

Anyway, £20 more but as im struggling to build 360's of any colour at the moment i cant quote a lead time

[Alan Hilton]

The black would look great in a stearman maybe with just the heads black . Money for a 360 is burning a hole but the model isnt even half built yet

Alan

[Rich too]

Hi Jon,

I am researching a motor for a Goldberg Ultimate and your new 180 petrol was mentioned, what does it weigh?

Thanks

Rich

Edited By Rich2 on 08/04/2017 11:44:20

[Jon H]

Posted by Rich2 on 08/04/2017 11:43:31:

Hi Jon,

I am researching a motor for a Goldberg Ultimate and your new 180 petrol was mentioned, what does it weigh?

Thanks

Rich

Edited By Rich2 on 08/04/2017 11:44:20

No idea! its not finished yet

I'm pretty sure the 180 will seriously over do it though. Those were intended for a 60 two stroke and at 54'' and 8.5lbs our 100 single would have no trouble pulling it around

Our 180 petrol will be quite a lump as it was always intended as a scale engine so has a large heat sink for a crankcase to help it out in cowlings etc. Currently its hauling an 85'' model of about 20-22lbs as a torture test. I'm trying too get a video shot showing the performance.

Edited By Jon Harper - Laser Engines on 08/04/2017 12:14:27

[Rich too]

Jon, I tend to stick to petrol these days for simplicity, I don't want lots of different fuel laying around. However, I do have a few glow motors waiting for their homes to be built!

Is there a blend of fuel that you would recommend for your 100, that would happily run a Saito 40fs, Irvine 53 abc, and a Moki 1.35 (I think that's the size I have )?

The rest of my motors are petrol, and I intend to run them all on the same mix.

Much appreciated.

[Jon H]

I would use the Laser 5 or techpower 5 from model technics. Myself and the guys at my club use it on OS, ASP, SC, Enya, Laser, Irvine and Saito two strokes and 4 stroke. All run fine and are cleaner than on other fuels.

its 5% nitro and 15% synthetic and while that is not exactly what some manufacturers (like moki) will recommend I cannot see any reason for it not to work in the moki. One of my customers said he was going to try it in his moki 180 but I never heard anything back

[Rich too]

Thanks Jon, that's good to know. What's the current lead time on the 100?  I notice you've also got a 120, you don't recommend that? It's quite a bit more expensive than the 100, is it that much more powerful?

Edited By Rich2 on 08/04/2017 14:39:24

[Former Member]

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[Rich too]

Thanks Percy, I would think that the 120 would suit the lighter and sporty Ultimate.

[Jon H]

Percy pretty much has it down.

The 100 is long stroke and has bags of grunt, but its not so long in the stroke that it wont rev. As I mentioned on the other thread, it will take a 14x7 to 9k without any trouble. I use one in my 9lb 68'' great planes escapade and it works a treat.

the 120 turns the same props as the 100 but takes them to higher rpm. Its shorter in cylinder height but slightly longer. Its short stroke and while really nice its not as versatile as the 100. The 100 is also very quite for those worried about that sort of thing.

[Rich too]

Ok, but when would you recommend the 120? I would have thought the light weight Ultimate would have been a good match, and the 120 would produce in excess of 10lb thrust and give good vertical performance.

[Former Member]

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[Former Member]

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[Jon H]

again Percy is on the money.

If the model was a touch larger then the 120 would be fine, but at that point the 155 becomes a possibility.

The 120 is not our most popular engine as its not that far off the significantly more powerful/versatile 155 in terms of price and the difference in price between it and the 100 brings the question of price/performance into play. In all honesty, the only people who buy the 120 these days are those building brian taylor hurricanes, spitfires, P51s and 109's as the Laser 75 or 80 shown on the plans is really not man enough given the fact that most cannot build down to the same weights BT used to and the 100, while powerful enough, wont fit in the cowling.

If you had a 65-70'' span cap or extra the 120 would be great, its short cylinder and smooth running at high is rpm make it ideally suited but the Ultimate might just be a bit too small. I'm sure it would be ok, but I think the 100 will give you all the performance you need. If however you find the 100 wont fit the cowling then the 120 is the clear choice.

Percy also makes an interesting point about the perception of long stroke engines being plodders for old men and that is really not the case. Last year I made a really long stroke 120 and found that if I plotted the performance of the engine on a graph output peaked at about 7000rpm. The engine had a stroke considerably longer than its bore and 7000 is still a pretty substantial rpm when you are talking about 17x8 props. Sure this was a plodding engine, but it was waaay long in the stroke and still hit 7k. All of our other engines are still over square and will rev if you want them too. The 360v at 8500rpm is quite the force to be reckoned with.

My future engine designs are leaning towards longer strokes as larger engines want to rev more slowly anyway and you get greater efficiency from the prop. You also get lower noise and instant thrust when the throttle is opened as you don't need to wait for the prop to spool up a few hundred revs to get your thrust increase.

Something like a radial would also have to be long stroke to get the revs down low enough to get that radial sound. a larger 100 or 120cc v twin with long ish stroke also appeals to me and would make an interesting alternative to a two stroke petrol and would offer 90% of the presence of a radial at probably half the cost.

But, I have to get the 180 sorted first

[Bob Cotsford]

One thing that struck me when I first ran up my new (to me) 100 on a 15*6 was how fast it spools up - the throttle is like a switch! I'm used to ASP, SC and OS four strokes and was well impressed with the Laser. Now if only the carbs were more conveniently positioned

[Former Member]

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[Bob Cotsford]

OS carbs are pretty good too Brian. I wondered whether the smaller carb choke area helped with the fast throttle response. After all, large engines rely on accelerator pumps and the like to cope with this situation, a smaller inlet may cope better with the sudden demand change on our simple carbs. What do you think Jon?

[Former Member]

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[Rich too]

Thanks for all the info gents.

I believe the cowl is 180mm ( thanks Adrian) and therefore the 120 will probably be the only one that fits in the cowl.

Unless I have the head sticking out ....mmmm

Edited By Rich2 on 09/04/2017 11:23:03

[Former Member]

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[Jon H]

Posted by Bob Cotsford on 09/04/2017 09:36:15:

Now if only the carbs were more conveniently positioned

we can move it, but then it wont throttle as well