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Laser Engines - Technical questions

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Jon - Laser Engines25/06/2019 20:06:39
5399 forum posts
261 photos

It should be fine. I look forward to a video

Frank Skilbeck15/07/2019 15:40:00
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4663 forum posts
101 photos

Just reading the last couple of posts for large slow biplanes with a 180 using a 20 x 6 prop, I have just acquired a Mick Reeves 1/4 scale Camel with a 200v cheekyyes, it's currently fitted with a Graupner 16 x 8, would a 20 x 6 be more appropriate, I have a wood Powermax 20 x 6 I could try.

Edited By Frank Skilbeck on 15/07/2019 15:44:28

Former Member15/07/2019 16:49:18

[This posting has been removed]

Alan Hilton15/07/2019 18:09:37
124 forum posts

Hi Frank

I have db 1/4 scale pup with a 200 v twin a 20x 6 prop is ideal

Alan

Jon - Laser Engines15/07/2019 18:43:39
5399 forum posts
261 photos

yup, 20x6 at least. 16x8 is too small even for an aerobatic model. It will do over 10k in the air on that prop!

I found a 22x6 at wings n wheels last year and the 200v will just swing it. Revs are low, but it would be ok in a pup and i will probably use it on mine when i eventually get it built. 20 and 21x6 are totally safe.

Don Fry15/07/2019 19:57:39
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4557 forum posts
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Posted by Frank Skilbeck on 15/07/2019 15:40:00:

Just reading the last couple of posts for large slow biplanes with a 180 using a 20 x 6 prop, I have just acquired a Mick Reeves 1/4 scale Camel with a 200v cheekyyes, it's currently fitted with a Graupner 16 x 8, would a 20 x 6 be more appropriate, I have a wood Powermax 20 x 6 I could try.

Edited By Frank Skilbeck on 15/07/2019 15:44:28

Please tell me, either the motor, and/ or the airframe is a wreck.

Frank Skilbeck15/07/2019 22:20:32
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4663 forum posts
101 photos

All, thanks I'll start with the 20 x 6.

Don, sorry no, the motor hasn't had much running and the airframe although built quite a while back has only flown a couple of times. Just need to replace the undercarriage and tail skid "springing".

Don Fry15/07/2019 22:22:22
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4557 forum posts
54 photos

Cow.

if not a state secret?

Edited By Don Fry on 15/07/2019 22:23:30

Edited By Don Fry on 15/07/2019 22:24:51

Dirk Witvrouwen 117/07/2019 17:22:16
6 forum posts

How critical is the methanol purity for the engine's health? Meaning, as of what purity % is the methanol OK for use?

I understand that lasers can run without nitro, if not too cold. Above what temperature are we talking to hold a fair idle? Or is this rubbish; and is the 5% nitro a necessity for all but the brave?

I'm asking since the locally available glow fuel seem dodgy, they don't even state the oil % properly, let alone the type (I called the hobby shop to check, they did not find the oil %).

Frank Skilbeck18/07/2019 12:07:19
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4663 forum posts
101 photos

Well I ran the 200v on a 20 x 6 and it started and ran well, no test flight though as a faulty throttle servo wouldn't let me get a slow enough idle. But the laser sounded superb and was very smooth, much much smoother than a DLE 32cc petrol I have in another model.

I ran it on on Southern Model crafts 10% nitro synthetic initially, but think I'll try 0% nitro synthetic next time (having run my Laser 61 on 0% in the past with no issues).

Jon - Laser Engines18/07/2019 12:41:32
5399 forum posts
261 photos

Dirk, i would always recommend you find the best quality methanol you can. Any water in the fuel can cause erratic running, poor reliability and corrosion within the engine. You are right to be wary of fuels that do not list their ingredients. We do not warranty engines run on fuels where the contents is not known.

On the nitro side, more than 5% is not of any real advantage and does little to improve performance. Above 5% nitro fuel consumption will also increase exponentially as % of nitro increases.

Dirk Witvrouwen 121/07/2019 12:26:03
6 forum posts

Thanks for the replies relating nitro percentages.

Once my 180 arrives, I'll probably be using Hobby-In mix initially. Their standard mixes use a minimum of 20% Klotz though.

https://hobbyin.nl/product/brandstof-met-klotz-olie/  (edit, added link)

I'll await the arrival of my 180 before purchasing anything; assuming the engine comes with break-in instructions/requirements.

Edited By Dirk Witvrouwen 1 on 21/07/2019 12:26:57

Don Fry21/07/2019 14:54:08
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4557 forum posts
54 photos

Dirk, given that your proposed fuel has a high oil content, it could be mixed 50/50 with laboratory purity methanol (99.85% or better), to give a 10% oil fuel. Use a 10% nitro methane base, if you want to end up with 5% fuel at 10 % oil.

if you are nice to Jon, and supply a list of ingredients I believe he will OK it's use with the warranty still valid.

Jon - Laser Engines21/07/2019 16:17:40
5399 forum posts
261 photos

Don beat me to it. Grab 10% nitro and 20% oil fuel then cut it in half. 5 nitro and 10 oil will be fine.

There are instructions in the box but assuming you have the right prop and plug fitted,  follow these simple steps for running in the engine. 

Start engine
Tune for max power. 
Fly

Thats more or less it. Dont run it rich, dont faff about on the ground for hours and hours, dont panic. Just start and fly. 

Edited By Jon - Laser Engines on 21/07/2019 16:20:37

Frank Skilbeck23/07/2019 16:58:48
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4663 forum posts
101 photos

Sorted the servo out on my 200v, on 10% nitro, it's turning the 20x6 around 6300 rpm, does that sound about right?

Plenty of thrust, should get to fly the model this week sometime.

tigerman16/09/2019 19:59:44
210 forum posts

Having real problems with my Laser 80 .it has not had a lot of running .It started going dead stick on me a lot .Tried everything I can think of ,clean the carb out ,check the valves etc .Finally took it out of the model and put it on a test bench to make sure the tank and everything was in the correct place .Now it will only run for a few seconds and stop .It does not seem to be drawing in the fuel .Mind you I have made things worse but completely fiddling with the idle setting .Now I do not have a clue how many turns the idle setting should me .I really have screw the setting up .Might have to see if Jon can fix it !!!!!!!!!.Looks like a phone call to Jon tomorrow and hope he is not to busy and then hopefully send it off to Jon 

Edited By tigerman on 16/09/2019 20:01:58

Former Member16/09/2019 21:03:04

[This posting has been removed]

tigerman16/09/2019 21:22:26
210 forum posts

Thanks Andrew .That could be the problem .Just looks it up and the correct setting for the idle jet was 7 turns out .Mmmm mine was 3 .Just set it at 8 turns out turn and it cough and splutter but then it sprung into life and look promising .It is a bit dark out there at the moment but I had it running for about 5 minute and then shut it down .( do not want to upset the neighbor .I will give it another go tomorrow when it is not so dark .I take it the idle jet was almost closed with only 3 turns out .Would that affect the running of the motor or would that only effect the slow running of the motor ? Any how it is a lot better now Thanks

Martin Harris16/09/2019 22:50:50
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9257 forum posts
245 photos

The idle needle setting is significant to probably 3/4 throttle and works in conjunction with the main jet throughout its range. It looks like Andrew has hit the nail on the head...

You may have (or have had) a partial obstruction inside the carb. If I suspect this and can coax the engine to run at full throttle (judicious finger on the exhaust or air inlet if no pressure is being used) once running at WOT, that finger gets used to choke the engine momentarily and draw the obstruction through. If you do try this, be extremely careful though.

Alternatively, a wide open needle valve and my u/c pressurising bicycle pump applied to the fuel inlet performs a similar function - cycling between that and removing the needle and pumping with the magic finger over the carb throat a couple of times usually works wonders...

Former Member17/09/2019 08:56:13

[This posting has been removed]

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