By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

Laser Engines - Technical questions

All Topics | Latest Posts

Search for:  in Thread Title in  
Jon - Laser Engines25/06/2019 20:06:39
4775 forum posts
179 photos

It should be fine. I look forward to a video

Frank Skilbeck15/07/2019 15:40:00
avatar
4430 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

Percy Verance15/07/2019 16:49:18
avatar
8109 forum posts
155 photos

A 16x8 is what I used on my 1.50 when I had it Frank. A 200v will readily pull a larger prop..... That 20x6 might be a good starting point. It does sound about right.

Alan Hilton15/07/2019 18:09:37
93 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
4775 forum posts
179 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
avatar
3841 forum posts
42 photos
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
avatar
4430 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
avatar
3841 forum posts
42 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
2 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
avatar
4430 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
4775 forum posts
179 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
2 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
avatar
3841 forum posts
42 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
4775 forum posts
179 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
avatar
4430 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
164 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

Andrew Ray16/09/2019 21:03:04
avatar
703 forum posts
19 photos

Laser have the base setting for the carb here.

tigerman16/09/2019 21:22:26
164 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
avatar
8741 forum posts
214 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...

Andrew Ray17/09/2019 08:56:13
avatar
703 forum posts
19 photos

That's great news tigerman. Lasers do not dead stick unless there is something fundamentally wrong. The only reasons I have had a Laser stop in the air are running out of fuel and a 75 carb coming adrift. Otherwise I find them very tolerant when setting up so much so that I fitted a new carb to one of my 80s (the engine fell on the floor and damaged the carb!). The engine ran and ran well with the new carb without any adjustment at all, transition was faultless but it was using a tank of fuel in half the time and a load of oil on the model, I was about half a turn too rich on the idle needle. You may well have been too lean on the idle needle, time to run a tank through the engine but don't fiddle with the settings too much.

Jon runs the new engines and they are pretty much set up perfectly, all I do is tweak the needle at full throttle to judge how lean the engine is running at with my prop and that's it.

Once set leave them alone, they don't need fiddling with from year to year let alone between flights. Mine start on the first or second attempt, they run perfectly and I don't touch them other than to admire them.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E! 

Latest Forum Posts
Support Our Partners
CML
Cambridge Gliding Club
Slec
Pepe Aircraft
Addlestone Models
electricwingman 2017
Wings & Wheels 2019
Gliders Distribution
Advertise With Us
Sarik
Latest "For Sale" Ads
New Poll - Sticky situations...
Q: How often - when using superglue - do you end up with it on your fingers?

 Every time
 Occasionally
 Sometimes
 Rarely
 Never
 Wear rubber gloves

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us