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Laser Engines - Technical questions


Jon H

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My friend in Cyprus had a starter that was far and away better than my Just Engines one, mine struggled with my 55cc DLE and it had a 4s lipo in it, and yes the switch had already departed, i glued a bit of ply on it, no more probs with the switch, cannot remember the name of my friends but it was good on 100cc , spun mine like it was not there, i will will contact him and get the details of it, i know it came from Germany

Tony

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Posted by Gary Spicer 1 on 24/03/2020 20:17:45:

Does 6900 rpm max revs sound about right for a 20x6 on a Laser 180? Model is DB Nieuport 24 (only a cheap tacho)

Thanks

My 200v runs a 20x6 at around 6,500 rpm so I'd say that's about right. Mines in a Mick Reeves 1/4 scale Camel, wt around 7kg, flew fine until a fuel line came off one of the carbs, engine didn't stop but didn't have enough power for a go around so landed in long grass flipping model over.

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Posted by Gary Spicer 1 on 24/03/2020 20:17:45:

Does 6900 rpm max revs sound about right for a 20x6 on a Laser 180? Model is DB Nieuport 24 (only a cheap tacho)

Thanks

i look for 6600-7200 depending on the brand. The cheap nasty hobbyking 20x6 on my stampe does 6700 but another i have (i forget the brand) does 7000. 200v's are normally faster than a 180 on an identical prop.

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Posted by Gary Spicer 1 on 24/03/2020 23:26:32:

Thanks Frank and Jon, sounds like I am in the ball park, its a birch wood ply prop cant remember the brand. AUW of the Nieuport 19lbs with 16oz tank. 92" span.

It will be fine. Takeoff at just over half throttle and then probably leave it there most of the time.

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they are quite economical if tuned up nicely and run on the right fuel. I think i had a 14oz in my stampe and it was certainly good for at least 25 minutes as i flew that long on a number of occasions and still had some left.

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Posted by kevin b on 25/03/2020 17:30:37:

Slightly off topic, but I think Jon should self isolate at the workshop, whilst all the other staff are off. He will be able to use the machinery to turn out lots of lovely new engines !

wink 2

Its a nice idea but i need the others to run the machines. Also, if supplies of ali and steel continue to decline we will all be twiddling our thumbs anyway

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Jon,

I started this Brian Taylor Bf109 about 5 years ago but then work got in the way. Its 3/4 built but I'm afraid to say I totally ignored your advice about tank height. I've followed his instructions and placed the tank where he suggested. Underneath the tank is the flight battery and the throttle servo. So now I've got time to advance the plane but I've looked again at the tank position.

Moving the tank would be very hard.

I could try turning the engine upright but fear it would poke out the top of the cowl.

Or, I could leave it as. The height difference is about 4", what would happen if I left it like it is?

The picture shows the approx. tank feed and the carb inlet with the two short red lines.

The curved lines top and bottom is the approx. cowl position.

img_0134.jpeg

What to do? Thanks

Bucks

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Posted by Bucksboy on 02/04/2020 17:19:28:

 

Or, I could leave it as. The height difference is about 4", what would happen if I left it like it is?

 

 

It will stop whenever you go upside down, which is not ideal.

That angled plate behind the engine at the bottom of the fuselage, what lives in there? I would be tempted to just chop through that angled plate and stuff the tank in there.

Also what size tank are you trying to use? even 10oz would probably do if space is tight. No need to fit a bucket

109 tank.jpg

Edited By Jon - Laser Engines on 02/04/2020 17:37:48

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From my experience with two Spits and a Stampe, all flown with Laser 180`s you should have no problem considering that inverted flight with the 109 is only likely to be brief. My Stampe does have a double tank set up (not chicken hopper) with a 9 at the top and a 6 underneath it so the effective fuel head is the 9oz and it will fly inverted all day.

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It looks like the saw is coming out tomorrow then. Thanks for the advice gents, I’ll just have to summon up the courage and set to. Of course the answer I wanted was ‘not a problem, don’t worry about it’. Still, there are bigger problems than this so I’ll crack on with it.

Thank you, I’ll post some more pictures when surgery is complete. 😄

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Posted by Jon - Laser Engines on 26/03/2020 08:13:51:

Its a nice idea but i need the others to run the machines. Also, if supplies of ali and steel continue to decline we will all be twiddling our thumbs anyway

Ah, plenty of time for development work then. yes

On a slightly more serious note, Some time ago I bought a cheap Chinese petrol strimmer to play with the engine. It has a copy (?) of the Honda 26cc OHC engine fitted to it (maybe I will have time now !). The question I ask, is why model engine manufacturers haven't developed OHC engines ? The advantages are obvious, but I assume there must be some disadvantages otherwise we would be seeing them. Particularly petrol versions.

Now there's a thought. An inline twin Laser with double overhead cams (One has to dream).

teeth 2

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OHC engines are too tall

As for an inline twin i already have 3 drawn up are ready to manufacture as well as 3 other things.

Not that it matters, the drawings for my radial were finished about 8 years ago and nothing has been done

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Sounds like a plan.

Radials for all!

I also think one of the first things i would do is make a reduction drive. Get propeller rpm down for much reduced noise. I already have the design done. It would fit our 100, 120, 150,155,160v, 200v, 240v and 300v with only one component change needed per engine and would allow a 200v to swing something like 22x14 3 blade or 24x14 2 blade at a gentle 4400rpm on the prop. Loads of thrust, nice and quiet.

Oh yes, it also would not make the engine more than a few mm longer than it currently is, and could be retrofitted to old engines.

Would be kinda cool i think.

I best keep dreaming.

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