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Laser Engines - Technical questions


Jon - Laser Engines

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Posted by Chris Walby on 14/12/2017 19:55:12:

When mounting laser engines is there any preferred orientation or is alignment with the tank the only critical factor, then ergonomics of connecting the throttle linkage/exhaust position?

What is the maximum noise produced by each engine (excluding prop and airframe), e.g. is under 75db achievable?

Do what you like with it, as long as the tank is in the right place they will not give two hoots which way up they are.

75db is really quiet and not likely to be easy to get down to. We have never tested the engines for noise as we lack the testing facilities to do so and any tests we do would be meaningless as the airframe and propeller used make such a huge difference.

Its a shame the old days of kit built models with foam wings are gone as these structures used to be excellent at absorbing sound. Modern artfs are like drums and its not always easy to keep them quiet.

All that said, I would not expect you to have any trouble with nose as our engines generally have a soft sound which is not as sharp as other 4 strokes that do not use baffled exhausts.

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Would you happen to have a parts diagram for those Super tiger carbs. Been looking on line and the info is a bit lacking. I stripped down 2 carbs today due to being jammed up, 1 was due to a small spring inside the throttle body, this one was smaller than the one in 2nd carb and was jamming against the spraybar. Sorted that with a Maplins spring but have another problem with the top needle seal. Should there be a small spring and o ring seal inside the brass thumbscrew ?

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Trebor, give Dave at motors and rotors a call. He might be able to help you with the ST carbs as he (and his father) were the distributor for many years. He may have more for you than that PDF shows. If all else fails I can supply new carbs for them as they are the later engine with the steel retaining clips but give the ST carbs a go first.

Bert, squish area (i assume thats what you meant?) is something we have experimented with over the years but its a balance. high compression gives good power but can make the engine less user friendly. We have set a bit of a middle ground between out and out performance and being easy to use/less fussy than some other brands when it comes to fuels and props.

 

Edited By Biggles' Elder Brother - Moderator on 15/12/2017 22:10:44

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Hi Jon,

I thought I’d post a shot of the “test fit of the 300v into an ESM Mig 3 cowl. Kinda sorta....

From what I can tell the 300v is very close to not needing any cutting for clearance of the jugs.

I took the Mig cowl and very carefully put it as far back on my Storch as I could I till it hit the front of the canopy which is really saying something when you consider how long and narrow the Storch nose is with the 300v hanging on there.

The end of the 300v prop shaft just lined up with the front edge of the Mig cowl so I had to center the engine within the cowl to see the clearance and it looks like there will be no cutting for the jugs. It does tapper but it looks to clear.

It doesn’t look like there is an extra 12mm in there to fit the 360v.... But I’ll measure more when I start ordering parts this summer.

It should be awesome with either engine

Joe

Do you think my Russian Storch would be ok at a scale event? lol

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I have a question that has been baffling me about installing a Laser engine in a scale model.When choosing an engine for a scale model in my view there is only one engine to fit ,of course a Laser.Now I am not the best model builder in the world but I could be one of the worse model builders.I have seen all of your lovely models with Lasers installed and they all seem to be installed inverted so they fit into the cowls without to much sticking out.How do you all manage to do this ? I have a Top Flight Texan and fitted a Laser 80 in it inverted to fit inside the cowl .The problem I have is how do you all get the tank in the right place because the carb is fitted high on the engine when you invert it the carb becomes very low and to get the tank in the right place is impossible (unless you strap it under the fuselage) Also because the carb is lower then the tank fuel leaks out of the carb and trying to get the engine to tick over is a nightmare .So how does everybody fit the Laser engine inverted with out incurring these problems.The reason I ask is I am about to buy a Laser 180 to fit in a Wots Wot XL ( this will not be a problem here because I am going to install it at right angles but latter on I want to put the Laser 180 in a big warbird but then I will come across this problem about installing the engine inverted and trying to get the tank in the right place.It frustrates me because I just love Laser engines .Just need to know how to overcome this problem ,everyone else seems to have solved this problem !!!!!!!!!!!!!!!!!!

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It doesn't matter what make the motor is, the innards of any model with inverted motor or misaligned carb position,

Has to hacked out or rebuilt internally to accommodate the tank

The bigger models usually have more room to lift or drop the tank, and so long as the alignment is nearer to

Optimum then it should stop syphoning,

Syphoning can be helped but taking the feed pipes up and then down to the carb

But the pipe can also be clamped when parking up

Or fit a non return valve to the carb fuel feed pipe

Edited By Denis Watkins on 16/12/2017 09:40:03

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Posted by bert baker on 15/12/2017 22:33:47:

img_1772.jpgHi it has J11 0n engine lug as well as my initials

The carb is broken it is a 150 do you still stock this carb

That carb is quite poorly. What on earth happened to it? it looks like the spray bar has been rotated about 90 degrees. the engine isn't going to appreciate that at all!

I can supply a new carb or we can rebuild that one.

Joe, the cowl on the mig really is a bucket, I'm kicking myself that I didn't buy one when I had the chance.

Rocker, the simple answer is to cut a hole and move the tank. If something is in the way, cut it out. This does over simplify a touch, as something like the WWXL will not allow this as the fuselage is not deep enough but most warbirds are chunky enough to take it. On my small hurricane I modified the wing leading edge quite a bit to allow the tank to sit where it needed to. It works well and the engine is quite happy.

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One of the advantages of building from a kit is that you can make these changes. I do accept though that sometimes there is some head scratching involved.

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@Rocker. Re the WWXL, if you at the specific thread for this ‘plane you will see how I fitted the tank in mine to feed the 160v. Basically I cut out a ‘slot’ in the provided tank platform and droppped my tank through that so it sits on the fuse on a bit of foam. I then have a ply bar that goes across the top of the tank which clamps it in place. Seems to work ok for me. Bit of a faff cutting out the slot but can be done with a bit of care and a saw blade attachment on my modelling knife.

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Posted by Ron Gray on 16/12/2017 09:51:08:

@Rocker. Re the WWXL, if you at the specific thread for this ‘plane you will see how I fitted the tank in mine to feed the 160v. Basically I cut out a ‘slot’ in the provided tank platform and droppped my tank through that so it sits on the fuse on a bit of foam. I then have a ply bar that goes across the top of the tank which clamps it in place. Seems to work ok for me. Bit of a faff cutting out the slot but can be done with a bit of care and a saw blade attachment on my modelling knife.

the 180 is likely to be too tall for this to work as the carb will be lower than the fuselage floor I think. I don't have the measurements so cant be 100% sure. mounting sidewider is a simple fix

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