New Laser engines. What do you want?

[Bob Cotsford]

In my opinion that covers it quite nicely Jon.

[Manish Chandrayan]

Jon

If this request has not come up earlier, how about including (even for a small cost) a template to mount and drill holes for the engine mounting?

You know the kind OS used to include with the engines earlier. They were pretty handy and saved the trouble of mounting dismounting the engine while carrying out various tasks.

These could be either included with the engine or available as an accessory to be purchased

 

Edited By Manish Chandrayan on 20/01/2016 14:51:50

[Jon H]

Hi Manish

I remember the things you mean. They were card and could be folded over the mount. I still have some kicking around at home. Its a neat idea, but i have to say i never once used them even when they were supplied with the engines i was mounting, and given that OS no longer supply them i can only assume demand for them was low?

It has never come up before, but if they are deemed to be valuable then i will look into how we could do it.

Bob, thanks for the feedback. This is what i hope to produce for the other engines when i get the time

[Former Member]

[This posting has been removed]

[Denis Watkins]

2 things Jon,

1. Thanks for the info on fuel, I appreciate what you are saying to be able to recommend a fuel, and I reinforced this looking on the Laser site, also

2. Has your survey thrown up any preferences, especially with small motors?

As a 61 would appear big in my hangar, and you start at 70 size

Thanks in advance

[Manish Chandrayan]

Jon
Do not think that OS discontinued those templates and the tools due to low demand. It was purely an economic decision.
May be if these do not make sense to supply a 1:1 downloadable template for users I am certain would be very useful.

[Don Fry]

Jon, my view, is you can provide lots of dimensions. But a simple solution Is to provide a good 3 view of the engine, a few basic dimensions, exactly as you do now, BUT INCLUDE A RULE ON THE PHOTO. Then any dimension could be extrapolated from the given dimension. Won't cost anything, and job done.

[Jon H]

Hi Denis. The subject of small engines has come up before on the thread and the short answer is no. The long answer is that they would be too expensive for the customer. The 70 is marginal as it is and we may in fact have to raise its price a smidge. So if we made a 50 or a 60 (like we used to) it would be no cheaper than the 70 and more or less the same physical size. In the past we did 45, 50 and 62. All gone as they were not cost effective to produce and noone bought them anyway as soon as the 70 came along. Also our 70 is the same height as an OS 52 anyway so just use that!

Ok 3 views and templates. Anything downloadable from our website is a pain. Mostly because our site is a pain to update and the control software (wordpress) is hopeless and so counter intuitive its really not funny. I could spend hours and hours trawling through the millions of posts on their 'support forums' in search of ways to fix the problems but i do not have time for all that nonsense. I wanted to update the gallery recently but nope, it flatly refuses now when it used to work fine. We are investigating other options for the website but it is a low priority.

Putting a rule on the drawings is a fine idea but believe it or not printing a scaled drawing is surprisingly difficult with the software we have. Again, i will figure it out eventually but do not have time now. For the moment the best i can do is get drawings to the standard of the one a few posts up arranged for the other engines. If however i remain as busy as i am currently i wont be able to work on them for some time.

[Denis Watkins]

Can I ask Jon.

The Laser v200 has 2 seperate fuel feeds.

Could you say how tge feed pipes would be arranged from a single tank

Thankyou

[Denis Watkins]

Apologies Jon

I have just seen the approved method on the Laser site

[Engine Doctor]

Just a thought and sorry if its been covered in previous post . Would it be worth making a optional spark ignition conversion kit available for use with the existing glow engines and supply the engines with mounting holes already drilled and tapped for the sensor etc ? The reason I ask is that the main reason glow engines stop is usually due to the plug cooling at low throttle openings . A spark ignition however would continue to spark all the while there is current in the battery and the engine is turning ; and providing there fuel engine will continue to run. No special carb needed either but that could also be a possible optional extra for those who like a pumped set up for odd installations . I realise that this was not a realistic option pre 2.4 radio as you had to fit various items like opto-isolators etc to stop interference ; but there shouldn't be any interference problems now that more people clued up on Spark ignition a appropriate installations. I also believe that the main change from glow to petrol power was not the fuel cost but the reliability factor . Sure petrol is the way to go for bigger stuff but noisy petrol engines or rather the use of the poor silencers supplied with them are a factor in many clubs having noise problems .

[Don Fry]

"Putting a rule on the drawings is a fine idea but believe it or not printing a scaled drawing is surprisingly difficult with the software we have. Again, i will figure it out eventually but do not have time now. For the moment the best i can do is get drawings to the standard of the one a few posts up arranged for the other engines. If however i remain as busy as i am currently i wont be able to work on them for some time."

Jon, what you need is not a scale drawing, just 3 view photographs with a rule in the same plane as the motor, ie the same photos as you have now, but with a rule included

[Martin Harris - Moderator]

Isn't the info already there?

I've used this scale to print out photos to check suitability for my current (rather slowly progressing) Tempest build. My thinking is that although it's a fair bit larger than really called for, as the weight will undoubtedly be needed and it seems it would just fit in the capacious cowling, a large prop and restrained revs should keep the noise down while sounding better than a smaller engine at closer to peak revs - although the Napier Sabre was a bit of a screamer!

While I'm at it, Jon - what are your thoughts? I know a smaller engine would be sufficient for a 76" Tempest but as a long term investment it seems more sensible to go for the 200 over the 160v, 155 or 180. What's the quietest prop size suitable for the 200 in a warbird of that size - and could I perhaps pop in to AGCs one day with my cowling to make a proper assessment of whether it would fit inside?

Edited By Martin Harris on 23/01/2016 12:57:36

[Jon H]

Hi Guys

In answer to the various questions....

We are not likely to mod the front housings for CDI units as there is no reliability advantage in running CDI vs glow. The primary reason for engines stopping at idle is incorrect mixture settings on the slow speed needle and this drowns the plug. While there is a perceived improvement in reliability with a CDI unit the additional variables and points of failure count against it in reliability. Some people have converted their engines to use cdi with glow fuel, and I have done one myself for testing. There is no improvement in power, a small improvement in fuel consumption and a small improvement in the idle speed. But as the engines normally idle at 1700-1900rpm for all but the 70 (about 2000-2200 for the 70) there is no advantage in an idle that is even lower. We would also have to redesign the shape of the front housing as the holes for the screws would go right through as the material is not thick enough to take them. This redesign would add weight to the engine and look unsightly having unused screw holes and a strange shaped FBH for those not using CDI. I have not had an engine from any brand cut on me at idle or in flight for many years unless there was a specific reason (fuel ran out, gunge in the needle etc). I have found that tuning low end needles is easier with lower nitro and lower oil fuel due to the fact that there is less goop in the cylinder fouling the plug.

Dimension drawings...if we are all happy with the photo of the engine with a ruler in the frame then I can do that. I didn't consider it before as I thought it looked a bit...ok I cant use the words I want to, but it didn't look good in my opinion. It just seemed like a lazy cop out instead of doing it properly!

Martin, the engine for your tempest depends on a few things. Model flying weight, available cowl/fuselage space, cooling potential, c/g of the finished model.

If the model is 12-15 lbs the use the 155. If its heavier or needs alot of lead in the nose use the 180. If its over 17 lbs use the 200v. I would sort of ignore the 160v as it is a short stroke engine and while it will have the power it will not really turn props that would look good on the tempest. None of them will turn a scale prop, but the 180 and 200v will easily turn 18x8's. The 18x8 would most likely be the best for noise on both of the two engines.

It probably would be easiest to pop in with the cowl/fuselage and we can go through all the options.

[Former Member]

[This posting has been removed]

[Martin McIntosh]

Why not just use a single clunk and a T piece?

[Gordon Whitehead 1]

Apparently one cyinder can starve the other of juice, causing the latter to cut.

Gordon

[Martin Harris - Moderator]

Posted by Jon Harper - Laser Engines on 23/01/2016 14:20:57:

Dimension drawings...if we are all happy with the photo of the engine with a ruler in the frame then I can do that. I didn't consider it before as I thought it looked a bit...ok I cant use the words I want to, but it didn't look good in my opinion. It just seemed like a lazy cop out instead of doing it properly!

Wouldn't a ruler in a photo introduce parallax issues? I'm still not sure why the dimensions on the existing illustrations aren't sufficient if used to print a copy out at full size. Most graphics programs include a specified sized grid pattern that can be overlaid on the picture in order to rescale the known dimension to 1:1

[Former Member]

[This posting has been removed]

[Jon H]

Unfortunately in these days of ARTF, the idea of moving mounts about and cutting things causes some (not all by any stretch) modellers sleepless nights. I have in fact encountered people who looked at me with  such a fear in their eyes when I suggested moving a fuel tank that it made me think I had mistakenly asked them to perform brain surgery on their child with a blunt pickaxe and as the sun was setting it would need to be done by moonlight....and it was cloudy...

Ok perhaps I exaggerate... but in fairness it does make the lives of many people much easier if they can measure up, look at the dimension drawings and go 'ah ha!! al I need is to do XYZ' or 'bonus, it fits without mods'. Personally, I go with the 'yeaaa that will go in there if I make it' approach and just do what is needed to make it work. But if people have only ever flown artf models they may not have the skills needed for such work. Its not their fault, just a fact.

I will get on it asap, but I must get the orders finished first, and our prototype pump/carb for the petrol as well as other prototype parts for something else.

 

So, as it was referenced above....

Fuel tanks for V twins must be either two individual tanks, or one with two clunk lines. T pieces will not work as the intake strokes draw fuel from the other cylinder and not from the tank. This is because it is easier to suck fuel the short distance from the other carb than it is the long distance from the tank. If non return valves were fitted to the carb lines from the T it would work, but, complication, reliability, more to go wrong etc. Anyway the upshot is that if you use T without non return valves the whole thing is uneven and just dosent run smoothly. The throttle response is bad too so I really wouldn't recommend it

 

 

 

 

Edited By Jon Harper - Laser Engines on 23/01/2016 22:28:07

[Derek Stevenson]

This thread has slowed down, you must have answered most of the questions Jon!

I've recently purchased a second hand Laser 150, one with a purple carburettor. How many turns are the recommended needle settings to start with? Does the purple carburettor tell it's approx age?

Hope it runs as well as my Laser 70, it ticks over like a Swiss watch.

Derek

[Jon H]

Hi Derek

I thought the same, either that or i frightened everyone away

Anyway your 150 will be about a 1995-2002 ish if it has a purple carby. If in doubt, pop a photo of it up here and i will be better able to identify.

Needle settings are a funny thing. Until recently we had no factory settings as we just took the engines out and ran them. We had no idea what the needles were set to because it didnt matter, the engines we set correctly and that was all that was important. However my experience of the past 5 years here is that a large proportion of modelers are unable to cope with an engine that is significantly out of tune and needs to be set up from scratch. Just to clarify one thing, i mean no disrespect to anyone with my last comment It just came as a surprise to me that a great many people do not seem to know or understand the signs being given off by the engine and therefore do not know how to put it right!

So, to help everyone out i now suggest 2 or 3 turns on the main needle, 6 turns on the slow run and have at it. These settings will not be definitive, and they will need changing to suit your installation/fuel etc but they should at least get the engine started.

To help a little more, i have a video here of me setting up a 150 that was way out of tune on both needles (rich massively). There is a written procedure to go with it but its too long for the forum to accept. Note also that we do not recommend the 'nose up' test. its a waste of time and proves nothing (unless you prop hang).

Edited By Jon Harper - Laser Engines on 22/02/2016 16:42:36

[Artto Ilmanen]

Thanks Jon! Your videos are always very educative. By the way, thanks for the 300v and 360v videos, too

[Mark Reynolds]

Thanks for a very helpful discussion. I am a typical club flyer in that I am looking for well made engines using petrol around the 25cc - 50cc size. I would welcome the chance to get a lazer 200v engine running petrol.

 

I don't like glow because of the mess it makes and because it is hard to get hold of and the quality is very inconsistant. I live in Wales and model shops are few and far between.

 

Has any decision be reached about new models or fuels as yet?

 

Thanks for all the input.

Edited By Mark Reynolds on 02/04/2016 11:23:36

[Artto Ilmanen]

Mark,

Just mix your own fuel at 10% good quality oil such as ML-70. Not much mess and cheap. I too am tempted with petrol engines as they do have certain advantages. However, glow engines are much easier to adjust the needles & less prone to overheating which helps with cowled installations.

-Artto

P.S. I do think that if Jon / Laser engines can sort out the carb issues then we may have a killer engine in hands: a pumped petrol Laser.