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Laser Engines - Technical questions

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bert baker20/08/2018 09:40:16
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1234 forum posts
267 photos

Is a 20-10 wood prop on a 180 glow in a quarter scale pup over doing it

bert baker20/08/2018 09:40:18
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1234 forum posts
267 photos

Is a 20-10 wood prop on a 180 glow in a quarter scale pup over doing it

Chris Walby20/08/2018 09:47:53
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691 forum posts
128 photos

Bert, Laser web site says, Recommended props

17×8-10 18×8-10 19×6-8 20×6"

20x6 to 20x10 would make for a speedy pup and not a lot of low speed fidelity ! However if you consider its not enough engine for the model PM me wink

Percy Verance20/08/2018 09:59:28
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7102 forum posts
142 photos

wise owl

As far as I'm aware, Neil Tidey is retired and is no longer actively involved in engine development and production. He may still be a Director, I'm not sure. He's certainly still an active model flyer as I spotted him on the flightline at the OW Scale Weekend a few weeks back....

Jon has now taken over engine development at Laser, and I belive the 155 is the first of his offerings. I'm sure there are more to come, but the senior management at AGC ( whom produce Lasers) seem to have decided that other things now have priority, as they don't just produce model engines. As has already been mentioned, a full frontal assault on the US market with the petrol versions should now be on the table. You can plainly see Jon's frustration, but his hands do seem to be rather tied.....

And yes Ron, as someone who has previously bought five Lasers, I think I'd have waited...... Saitos are indeed good, but they're not Lasers..........

At least we don't seem to have had anything like a speculative market developing, in a similar manner to that with Morgan cars. Some *customers* whom didn't actually want a car were ordering, then when the car was ready for collection they immediately placed it on the market at an inflated price........ And of course there are always those whom will pay a premium rather than wait three years.

 

 

 

Edited By Percy Verance on 20/08/2018 10:13:03

bert baker20/08/2018 13:23:57
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1234 forum posts
267 photos

It goes round sky quite nice,,, but it’s not a rever, very nice for low wind days

Jon - Laser Engines20/08/2018 13:28:33
4157 forum posts
155 photos
Posted by bert baker on 20/08/2018 09:40:16:

Is a 20-10 wood prop on a 180 glow in a quarter scale pup over doing it

yea, 20x6 would be better. Its what i have on the stampe

Grahame Pearson29/08/2018 11:56:20
11 forum posts

High Speed Needle O ring question.

I have a Laser 100 (later black carb type) and I had a problem yesterday where I noticed the high speed needle O ring had worked its way inside the spring making needle adjustments ineffective of course. I'm sure this is not a common problem but is my case an isolated one?
Anyway, to ensure it didn't work its way inside the spring again I added a washer between spring and O ring. The hole in the washer fits over the threaded part of the needle and the washer then sits on the needle housing (the bit the needle threads into). Not sure why it has a tendency to work its way inside the spring but my question is, will the O ring be properly seated now, with the washer added? I imagine it will be as the washer is pressing it down just like the spring should do.
Thanks.
Grahame

Jon - Laser Engines29/08/2018 13:36:26
4157 forum posts
155 photos

It sounds like there is a piece missing from your needle. They should have a washer for the spring to push on as shown below.

20180829_133413[1].jpg

Grahame Pearson29/08/2018 15:09:51
11 forum posts

Hi Jon,

That's interesting. I recently bought the engine secondhand. So, it would seem that my washer has simply replicated the missing washer!

Grahame

Don Fry29/08/2018 15:23:21
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2887 forum posts
35 photos

Convergent evolution in action.

Martin McIntosh30/08/2018 15:05:30
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2592 forum posts
963 photos

Not a question but a trap I fell into with my 155.

Found a Xoar 18x7 at the nats so decided to try it. Prop nut well tightened but after about 8 mins there was a nasty sound as though it was loose. The motor idled normally so I landed it for a look at the problem back home. The nut was still very tight but each time I attempted to start up it was thrown off. The washer was locked tightly onto the shaft and took quite some removing. The prop rear was burnt, with the burnt bits embedded into the driver.

It turned out that the prop was thinner at the root than those previously used so that the nut was only tightened onto the unthreaded part of the shaft and not really grabbing the prop. A thicker washer cured it.

Jon - Laser Engines30/08/2018 21:23:47
4157 forum posts
155 photos
Posted by Martin McIntosh on 30/08/2018 15:05:30:

Not a question but a trap I fell into with my 155.

Found a Xoar 18x7 at the nats so decided to try it. Prop nut well tightened but after about 8 mins there was a nasty sound as though it was loose. The motor idled normally so I landed it for a look at the problem back home. The nut was still very tight but each time I attempted to start up it was thrown off. The washer was locked tightly onto the shaft and took quite some removing. The prop rear was burnt, with the burnt bits embedded into the driver.

It turned out that the prop was thinner at the root than those previously used so that the nut was only tightened onto the unthreaded part of the shaft and not really grabbing the prop. A thicker washer cured it.

props sure do make a weird noise when spinning slightly slower than the engine they are attached to. You get a weird optical effect through the blades too

tigerman01/09/2018 15:28:07
125 forum posts

Can anyone tell me what the exhaust and inlet valve clearance are old the old style Laser 90

Manish Chandrayan01/09/2018 15:59:35
499 forum posts
59 photos
Question for Jon.
Was running my two tanks old 150 on the bench. Overall satisfied with the run but,what I noticed was that when opening the throttle, the engine actually sagged some when the barrel was fully open. If I pulled the barrel back a bit ( slightly less than full open) the engine peaked.
Tried richening the high end but that had no effect.
So, why is this engine behaving like this?
Does that mean that the engine is able to draw fuel better with the barrel slightly closed?
Can't remember if I noticed this when I ran the engine earlier
Grahame Pearson01/09/2018 17:03:07
11 forum posts

Valve clearances on Laser 180


Just bought a secondhand Laser 180 which looks to be in good condition. A quick question, are the valve clearances the same on ALL Lasers, i.e. 0.05mm - 0.10mm?

Thanks.
Grahame

tigerman01/09/2018 18:23:04
125 forum posts

Well that answers my question ,0.5 to 0.10.Next question .My exhaust valve had quite a gap and the inlet valve was tight close with no gap ,would this explain the lack of power from my Laser 90 or is this wishful thinking and the real reason is it is old and knackered and time to replace it !!!

Grahame Pearson01/09/2018 18:41:47
11 forum posts
Posted by tigerman on 01/09/2018 18:23:04:

Well that answers my question 0.5 to 0.10 …

To clarify, it's 0.05 not 0.5. (that would be half a millimetre, far too big).

Rob Tothill02/09/2018 18:32:08
111 forum posts
8 photos
I had the same question about valve clearances. I am just setting up an old 1.20 after 9 months of not doing much modelling (our first baby is 6 months). I went for a cigarette paper as valve clearance, as I have previously done with saitos. Is that too small a gap?

I also wondered what is a decent idle on a 15x6?
Denis Watkins02/09/2018 18:41:52
3197 forum posts
147 photos

Rob, a fag paper is OK but a bit compressible and can distort.

Any gap is better than no gap, even a fag paper, but a feeler will be more accurate obviously.

Most motors will land a model at 2000rpm, but most manufacturers prefer idle around 2400rpm to retain some heat, and fuel supply, and inertia

And at those revs the prop is usually stalled and no longer pulls the model along

Edited By Denis Watkins on 02/09/2018 18:42:58

Rob Tothill02/09/2018 18:54:03
111 forum posts
8 photos
Thanks Denis. I have it about 2500 at the moment and about 9000 at the top end (5% nitro). Does that sound okay? I'm on pro power 5 so a lot of oil in the fuel. It's a bit smokey at idle but picks up well after the 30 second test. Does that sound okay?

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