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Laser Engines - Technical questions

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Jon - Laser Engines26/09/2018 14:02:49
5510 forum posts
268 photos

Ron pretty much has it covered to be fair. A single tank with two clunks or two separate tanks are needed. A T piece wont work.

Inverted is fine but just make sure you remember to lower the tank so its in line with the carbies.

No on board glow but twin remote's like Ron suggests are a good idea. That or wire the plugs in series and use a single 2-2.4v battery to power both.

Wooden props are fine if you keep them tight. Menz, fiala, APC, falcon...there are many good props out there. I like wood in the large sizes as they are cheaper, easier to drill for our sleeve nut, lighter (better throttle response and leaner slow run setting) and usually give good downline breaking. They also impose less load on the crankshaft in the event of a prang.

I guess the best advice is to not worry about it too much. Treat it like a single cylinder engine, all of the usual rules apply about tank position, cooling, glow connectors etc. The only difference is that there is two of everything.

Its the same with tuning as well. You essentially have two engines to tune, the fact that they are linked together is not really important. You start both 'engines' and the job is to sync them up. Tune one for maximum power, then tune the other for the same. Double check the first is still ok and you are good to go.

In terms of prop size, i guess 18x8 would be a good start. 17x8 will give more power, but it will rev pretty fast so might give a noise problem. An 18x8 menz wood hits about 7700-8k and that is plenty of revs for an engine that size.

tigerman28/09/2018 20:41:20
220 forum posts
1 photos

Will a Laser 180 power the Black Horse Chipmunk ,the 45cc one with the I think is 82" wingspan .I know it says it is for a 45 cc petrol engine but I am sure my Laser 180 would fly it but want to make sure before I buy the model .If it is not up to it ,it would be a good excuse to wait for the Laser petrol engines to become available but not sure if I will be able to afford one but they do sound good but I am getting away from my original question which is will my Laser 180 fly the big Black Horse Chipmunk ?

Edited By tigerman on 28/09/2018 20:41:45

Ron Gray28/09/2018 21:02:30
2172 forum posts
940 photos

The 180 glow powers my YT Hurricane without any issues which is 82" wingspan so I don't think you'll have any issues.

Jon - Laser Engines28/09/2018 21:06:39
5510 forum posts
268 photos

The 180 will monster it. The BH 45cc chipmunk has flown successfully on engines as small as an OS120. Personally i think our 180 is prefect for it as its long stroke and you can throw a 20x6 prop with ease. I really dont know why they suggested a 45cc engine for it. 

There is virtually no performance difference on 18-20 inch props between the glow and petrol 180. They take in in turns being faster but neither is ever more than 100rpm faster than the other.

Edited By Jon - Laser Engines on 28/09/2018 21:07:10

bert baker28/09/2018 21:21:12
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1609 forum posts
331 photos

I Have been flying the latest BH 45cc Chipmunk with a NGH 38 Petrol four stroke today,,, the Laser 180 will be great.

i have a 180 glow in a 88” Sopwith Pup and it is a great engine..I am waiting for the petrol 180 to become available then will replace the NGH in the Chippy...

Grahame Pearson29/09/2018 08:20:26
12 forum posts

I have the Apache Aviation/SLEC Chipmunk, a similar size to the BH one at 81". I bought it secondhand and am currently refurbishing it as it has not flown for a few years. It has a Laser 180 and the model has flown very successfully, around 50 flights, although I have not personally seen it fly. So, I agree with Jon that the 180 will be fine.

Jon, I was interested to see you say the 180 will swing a 20x6 on this plane (I am assuming the two Chippys are to all intents and purposes identical here!). Mine has an 18x8 fitted (Master Airscrew Classic). Would there be any advantage in me changing the 18x8 for a 20x6?

Thanks,
Grahame

Jon - Laser Engines29/09/2018 09:27:15
5510 forum posts
268 photos

i use 20x6 on my stampe and its just perfect. I have oodles of thrust even at low rpm and the fine pitch means that speed is always under control. it also looks great

tigerman29/09/2018 09:28:12
220 forum posts
1 photos

Thanks everyone .I can order one with confidents now .I thought the Laser 180 would fly it the Laser 180 like all Laser is a great engine

David P Williams29/09/2018 11:16:37
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913 forum posts
318 photos

I also have the SLEC/Apache Aviation Chipmunk. I used it as a test bed to learn scale detailing like overlapping panels, inspection hatches, rivets, rib tapes and stitching etc., so it's a bit porky!

It flies absolutely fine on a Laser 150 - not overpowered, but will loop from level flight and pull up into good scale-like stall turns, so a 180 will be great.

tigerman29/09/2018 16:55:14
220 forum posts
1 photos

Just my luck ,someone has jus told me that Black Horse have stop making the 45 cc Chipmunk .I have just emailed Ripmax to see if that is true

bert baker29/09/2018 18:12:50
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1609 forum posts
331 photos

Does the 180 glow have a sealed front crank bearing

Mine appears to be blowing loads of oil out... runs ok but, thinking it’s getting hot

Martin McIntosh29/09/2018 18:38:09
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3419 forum posts
1213 photos

Grahame,

Fitting anything other than a Master Airscrew would be great. They are just noisy and generally lousy but I am forced to use their three bladers occasionally because of the lack of alternatives in the sizes I need.

bert baker29/09/2018 19:05:57
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1609 forum posts
331 photos

Using a Menz 20x10 wood

Jon - Laser Engines29/09/2018 19:20:16
5510 forum posts
268 photos
Posted by bert baker on 29/09/2018 18:12:50:

Does the 180 glow have a sealed front crank bearing

Mine appears to be blowing loads of oil out... runs ok but, thinking it’s getting hot

old ones were shielded but not sealed. new ones are sealed.

How hot is it?

Grahame Pearson29/09/2018 19:30:33
12 forum posts

Hi Jon,
I have a spare 20x6 wood (from Prop Guy, WW2 type: black with yellow tips). Would that be OK for my 81" Chipmunk with the 180 or would it be too light for a reliable low idle? As I said, it currently has a Master Airscrew 'Classic' 18x8.
Grahame

Don Fry29/09/2018 19:37:02
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4557 forum posts
54 photos

Sounds like it will fly it. Worth a try.

Jon - Laser Engines29/09/2018 19:51:25
5510 forum posts
268 photos

wood props are fine. If the idle is lumpy lean off the slow run a bit more but to be honest by the time you get to 18+ inch props the flywheel effect is pretty good.

Robert Hay 406/10/2018 11:23:47
48 forum posts
6 photos

Hi Jon,

I have an old Laser 180V twin which I intend to put into a DB SE5A. What prop size would be appropriate for this engine please? Funnily enough I see the latest topic concerns the modern 180, would the prop size be the same for the twin? Cheers. Rob

Former Member06/10/2018 12:24:12

[This posting has been removed]

Jon - Laser Engines06/10/2018 12:40:48
5510 forum posts
268 photos
Posted by Robert Hay 4 on 06/10/2018 11:23:47:

Hi Jon,

I have an old Laser 180V twin which I intend to put into a DB SE5A. What prop size would be appropriate for this engine please? Funnily enough I see the latest topic concerns the modern 180, would the prop size be the same for the twin? Cheers. Rob

Percy is quite right about the 160 but it is short stroke and the 180 long stroke. As a resuly it will be happy with 18x8 or 20x6. For the se5 i would use a 20x6 and see how you get on. If you see anything around 7000rpm you will be fine. If it cant make that then give 19x6 a go.

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