New Laser engines. What do you want?

[Derek Stevenson]

Appreciate the interesting reply, might just add some petrol to the glow fuel reducing the overall oil %

[AVC]

Posted by Jon Harper on 16/11/2015 21:23:46:

Is there interest in 40-60cc singles and 80-120cc V twins based on the same bore/stroke?

Definitely yes, especially the twins. I was considering a Roto 85 FS for a Hostetler Beaver 126'' (one day I will start building it...) but if a Laser was available I would go for it!

A flat version of the twins will also be a good choice, and a good competitor for Roto and Valach...

[Don Fry]

I see a low oil content glow motor, as a strong selling point. As a newcomer to petrol motors I like the fuel costs, like VERY much the lack of mess. But, if we are honest with ourselves, for most of us, fuel costs are a marginal cost in this game. But, I am struck that petrol motors require a lot of bits on board, which do not like other bits on board, and I conclude that a glow motor is a simple beast operate. But a pumped glow motor is a thing to be desired

[Don Fry]

And if you are investing in a big Laser, can you not see the desirability to future proof it as the pumped version. Just a thought.

[dave parnham]

I'm currently installing my 180 laser in a Balsa USA Fokker D7, it should be enough power but a 200 single cylinder would have been better, or 38cc to match the Zenoah that everybody else uses.

cheers dp

[Jon H]

Donald, I am in agreement with you here. There is a lot of clutter with a petrol engine and many more things to go wrong. I also agree that 15 quid on a gallon of glow fuel is insignificant when you consider the cost of modelling as a whole. That said, the cheap running petrol affords is tempting.

A pump is something that has come up a few times now so its on the list. The only issue we have is not having any way to deal with plastic so unless we can machine it then its not easy for us to do. I have had some ideas though and will continue to investigate.

Dave, the 180 should be wonderful in your D7. And if it makes you feel better our 180 is more or less a match for the 200 surpass, especially on big props. That said I do have some larger singles in mind. If you want them to run on glow then they could be ready very quickly.

In fact, just to clarify a few points. So far the biggest requests are 30 ish cc petrol, fuel pumps, and 160-200 inline/flat twins, larger radials 50-100cc and some big twins 80-120cc for 1/4 scale?

So, that's all good and sort of what I had in mind anyway. But the 160/200 inline/flat twin. DO we want glow or petrol? I ask as glow would be relatively easy and would shorten development time significantly. I also do not know if I can get a carb that will work on an engine that small.

Just to put some numbers to this, our fuel consumption is quite low vs other brands. To give an idea my 50cc 300v averages about 42cc a minute when flown exuberantly on 5% nitro glowfuel. Saito quote 35cc/min for their 36cc petrol engine and 25cc/min for their 30cc petrol. My 180 prototype which is 29cc uses only 12cc/min on average and this is why we are having some unusual issues with the walbro carbs as they are not really accurate enough with fuel flow this low. Which is why I am doing my own mods to these carbs to improve their performance

[Don Fry]

Jon, forgive the unit conversions, but my tanks are still in ounces. Do I read you right that the 180 petrol does 10 minutes on a 5 ounce tank.

[Jon H]

yes that's about right. I get 20-25 minutes from a 9oz so you are in the ballpark.

[Derek Stevenson]

On a seperate note, why do you not put the size on your engines, when I bought mine second hand, it was smaller than I was informed. I weighed it to work out what it was!

[Derek Stevenson]

On a seperate note, why do you not put the size on your engines, when I bought mine second hand, it was smaller than I was informed. I weighed it to work out what it was!

[Jon H]

Posted by Derek Stevenson on 18/11/2015 12:02:47:

On a seperate note, why do you not put the size on your engines, when I bought mine second hand, it was smaller than I was informed. I weighed it to work out what it was!

Not a clue! it was a historical thing that has never changed.

The 155 has been done since i introduced it but not the others.

I will be stamping the engines from now on, and will do the same with any engines that come back for service.

[will -0]

Any chance Laser arranging a reliable source of laser friendly glow fuel? I don't have any kind of local model shop at all and as others have said petrol might seem an attractive option for that reason except for the smaller model not really being so good.

OTOH if I could easily buy 4 gallons of MT Laser mix online that'd be extremely helpful to continuing running of Lasers (and other glow engines).

Alternatively is there an online laser recommended fuel already out there? Optifuel seems to be more high nitro heli stuff and weston (only other option I know of) is sort of lucky dip in that they don't mention what's in there

[Jon H]

Hi Will

Fuel is becoming an issue for some and i am aware of that. There is a bit of an ongoing discussion about us supplying fuel. i cant say we will but i think we should.

You are right about fuels where the components are unknown. Best stay clear no matter what anyone else says about how wonderful it has been.

Model technics pro power 10 should be easy to get. If you get a gallon of that and mix it with a gallon of pure methanol you will end up with 5% nitro and 9% oil and it will only cost about £30 for two gallons of fuel.

It might be worth starting another thread to cover issues like noise and fuels etc as this thread seems to be attracting comments on a wider range of topics than intended. I am not complaining, feedback is always helpful, but if possible could we stick to the topic on here and i can either create another thread, or add comments to 'the laser appreciation society' thread which is somewhere on the forum here.

[will -0]

Certainly running low nitro low oil glow power FS solves a lot of common complaints about glow (cost of fuel, mess etc) if you could just find an oil that works and doesn't attack paint that'd be fantastic!

It's a difficult one at the moment as currently the only gap I see is in the smaller engines which unless you crack finding a carb that works to run them on petrol doesn't seem like a large market to target, mainly appealing to motor tinkerers. Etc. I'd love a laser 45 TBH but then I'm strange like that. You'd have to educate people that making small engines with the same number of parts and assembly/test steps costs more or less the same as the larger ones as the cost of raw material ain't the main component!  Similarly your logic about petrol being cheaper to run than glow but not enough on smaller engines to make it pay counts for nothing if you can't get hold of glow fuel!

More complex but inefficient multicylinder engines would appeal to a few eg short nosed WW1 biplaners where power to weight isn't a problem but a radial would be lovely if it were reliable.

Realistically would it be worth the development investment though?

 

Edited By will -0 on 18/11/2015 15:51:06

[Martin Harris - Moderator]

Straying very slightly off topic, I've often wondered about the size/price model adopted by all manufacturers. It's always appeared to me that material/production/distribution/marketing costs etc. are likely to be pretty similar so where does the significant variation in price across the range come from? Do larger engines within a typical manufacturers range make a decent profit, mid size engines break even and smaller ones make a loss?

[Jon H]

I have had some success today with a new experimental setup for running on petrol. Its a total departure from everything else i have tried but for a first go i was very pleased with the results. I am going to continue research in this direction as this might be a solution that would apply to a smaller engine. That said, dont get your hopes up just yet!

Will your comments about the radials are spot on. If its a big fat thing that runs and lazily throws a prop that looks the part on a biplane then thats wonderful and a few people will buy them. The issue is this type of engine already esxists in the form the the Evo radials. They look lovely, sound lovely, by my goodness as they a faff to operate (read their run in procedure if you dont believe me) and they are not powerhouses.

I have owned the SC400 5 cylinder radial and the saito 450R3 and neither have impressed me greatly. The SC was just too badly made to work very well and rarely went more than 20 flights without a mechanical breakdown. It was also hard work to use and needed constant attention. In fairness to it however it was quite an old one and the current ones are improved in terms of quality.

The saito was a lovely engine in terms of quality but it was very heavy, very big and used twice the amount of fuel a Laser 360v does while producing no more power. It suffered problems with even fuel mix to the cylinders as well as some geometry issues with the conrods (this is my mechanical knitpicking) but was much easier to use than the SC and sounded ace! It was a nice engine, but as it wouldnt do what i wanted i sold it on.

If i do a radial, it needs to provide a decent amount of power and i have some ideas about how to achieve that. I will also stick to 3 cylinders for the reasons i mentioned before. I will also try and keep the dimensions and weight under control.

[will -0]

Go on go all out and make us a petrol 9 cylinder rotary

[kc]

My view is that whatever engine you decide to produce you should also ensure there is an ARTF airframe available that really needs that Laser engine. Many of the people with money enough to buy fancy engines don't bother building their own planes nowadays. Especially the younger generation- the skills to build a model are fast disappearing.

[Jon H]

KC I agree which is part of the reason for this thread.

Will, I would love to but we would probably only sell about 3

[Former Member]

[This posting has been removed]

[bert baker]

Petrol or glow I don't care but it will need to be below 82db whatever it is. I want a 20cc-30cc stock engine without the hassle of doing my own exhaust systems ever time.

[Jon H]

Hi Percy

As I have already detailed the issue with the small petrol's is firstly getting them to work properly, and secondly initial price and this is what will kill them. The saito FG11 is a good example. Its a .62 size engine but it is £300 which is only 15 quid short of our 120. I cannot believe that many people spend £300 on an engine of that size. Not to mention the fact that to fit the engine with its cast mount, a CDI and an extra battery into something like an acrowot would be problematic and heavy. With larger engines/models this is not such a problem.

as I mentioned before, a petrol engine from us is very unlikely below 30cc.

I was slightly nervous about starting this thread as I was wary of getting a load of unrealistic answers, not through anyones fault, but because secretly we all want a geared V12 with a variable pitch prop that has onboard start and sounds like a merlin even though we know it would be unaffordable and (from our point of view) not a commercial product due to the huge development cost and small market.

I am pleased to see that for the most part the comments have been extremely constructive and well within the realms of possibility and I hope I can make some progress on a few of them quite quickly.

One thing we have not talked about is costs and this is likely to be the real sticky bit.

A 160 flat twin with single throw crank and standard conrods would (I expect) be similar in price to its V twin brother. However this may not be the best configuration due to vibration, so a double throw crank with split big ends would be in order, which is the same as OS, saito and ASP etc. This is where prices go a bit mad as the OS (discontinued I think) had a list price of £1100...so I cannot see many of those being sold. The closest saito offer is the 182 (their only single throw crank engine) for about £650.

So if we made that petrol the price would rise by at least £100 and even if we undercut the competition on a split crank 160 flat twin and made it run on petrol with a list price of £700 would anyone buy it?

It is really tempting to think of petrol as a cheap option because if DLE and all the rest of it, but a quick scan of OS, Saito, Roto and Kolms price list might be a surprise.

Personally I think we could be much more keenly priced, but that is something that is out of my hands.

I don't wish to be the bringer of bad news or to be critical of anything anyone has said, but if some these suggestions were to go ahead and enter production, would you actually buy one at the prices they are likely to be?

[Don Fry]

Jon, as an engineering pigmy, I hesitate to speak here, but I am getting a recurrence of a design philosophy. You speak of fuel efficiency. I for one am not interested, I am not running a Volkswagen, does it start, tick over, go vroom, and not stop til I tell it to stop.And when a slight error of judgement occurs, I have a solid lump with a lot of the fragile, expensive bits at the back. I am on ordinary modeller.

I am astonished at the projected fuel efficiency of your 180 petrol. I have an airframe waiting, with a potentially stupid 8 oz tank in it, and I am starting to think why are you worried about challenging the ability of a Walpro carb to deliver fuel so the tiny tank can cope. The airframe can carry a bigger tank, why make an issue about fuel consumption. The other manufacturers don't. I realise that engineers are upset by such savage philosophies.

[Jon H]

Hi Donald

I am afraid you have the thing backwards. The tank is not the problem, indeed I damaged the 9oz tank so ran a 14 instead, and during initial testing I hooked the carb directly to a 1 litre bottle. The issue is that the engine demands only a certain amount of fuel and the carburettor must meter and control that fuel and supply it to the engine.

The problem is that the carb is not accurate enough to do that throughout the entire rev range. Things like acceleration are compromised. Now we can get around this problem if a 1-2 second servo slow is applied to the throttle channel to control the speed at which the carb opens. Personally I would be satisfied with this as you do not notice it when flying and (to be honest) you should not be slamming the throttle about anyway. However, this would not be received well I suspect and questions will be asked about why it is required.

The other option is a smaller bore carb, then the engine works better but at a loss of 600rpm which is unacceptable.

The only way to increase our fuel consumption would be to make the engine less efficient, which is sort of the wrong approach. Also an inefficient engine will not burn all of its fuel which leads to carbon buildup in the exhaust ports, combustion chamber and muffler which leads to all sorts of nasty things

[kevin b]

As I said before, an interesting thread.

I like Donald's comment about the "ordinary modeller". The petrol argument in my opinion is not so much the economy factor, as the "gunge" factor. Plus the more paint friendly emissions. I have never heard real motor cycle enthusiasts say "oh yes, but it only does xxx miles per gallon". One thing I haven't seen in any engine reviews over the years is fuel efficiency comparisons (I may be wrong). When we buy motor cars it is one of the first things we look at. Maybe we should ask the model engine manufacturers the same question ?

We all like playing with model engines, but at the end of the day a model Spitfire with either a 2 stroke glow, or 4 stroke petrol engine is still going to sound like a model Spitfire powered my a motor mower. So if you want realism, you will have to go for an electric "engine" and a good electronic sound system.