Methanol versus Petrol?

[Keith Miles 2]

I’m puzzled!

In a world of environmental concerns why, apart from going electric (I’m trying to avoid it!), does there seem to be a shift from glo engines to petrol?

As I understand it, methanol can also be produced from numerous sources including biomass and waste materials whereas petrol is a fossil fuel which, amongst other things, is less sustainable and, together with diesel, is now supposedly bad news!

I have read that methanol could also be used for heating and a number of other necessities of life.

So, unless I’m missing something, why, at least where IC model engines are concerned, do we seem to be moving in the wrong direction i.e away from a bio-fuel that seems to have a future and further towards a fossil fuel which doesn’t?

Oh, hang on, is it just because petrol is cheaper?

Surely not?

Edited By Keith Miles 2 on 09/08/2019 00:35:55

[Denis Watkins]

Yes Keith,

Petrol is cheaper, and more widely available

But is less powerful in our motor sizes, and the smell does linger

[Jens Eirik Skogstad 2]

Two engines of the same stroke volume, the one engine running on petrol consumes less fuel than the other engine running on methanol due to the high energy content of petrol: BTU per gallon (higher heating value) in petrol: 124,340 while methanol has BTU per gallon: 65,200.

Then you are flying the model more longer in time with petrol engine.. 

Edited By Jens Eirik Skogstad 2 on 09/08/2019 07:42:24

[Peter Christy]

Petrol engines also run hotter and need better cooling! I've only got one. Its noisy and gutless, and I would replace it if I could!

--

Pete

[Frank Skilbeck]

The other reasons is that Petrol engines run cleaner as they run on much less oil, a typical glow engine has 15+% oil in the fuel and a petrol engine around 3% add to that a methanol engine runs around twice as rich as a petrol engine, then a glow engine kicks out 10x more oil.

But noise is the big issue, I'm in the process or removing a noisy 32cc 2 stroke glow for a nice Laser 150 in my only petrol model for that reason.

[Bruce Collinson]

Ditto that, DLE 20 almost impossible to get down to a genuine 82dB without strangling it. Saito 125 gone in.

Re the OP, to me this is a bit like eating tofu and driving a noddy car with a battery. When the Brazilians stop cutting down the rain forest, I'll think about it. The size of the carbon footprint caused by petrol model engines is a drop in the ocean. Also, methanol might be all of the green things alluded to, but I suspect nitromethane is far from it.

BTC

[Jon H]

Posted by Frank Skilbeck on 09/08/2019 08:20:58:

The other reasons is that Petrol engines run cleaner as they run on much less oil, a typical glow engine has 15+% oil in the fuel and a petrol engine around 3% add to that a methanol engine runs around twice as rich as a petrol engine, then a glow engine kicks out 10x more oil.

That is the theory but i have tested our engines on 5% oil without any problem for a whole year and our petrol version are even as low as 1% in glow terms. So far its all been fine. I need to spend more time testing it before recommending it to all but certainly 10% oil is no problem and i really suspect 5 would be where it needs to be.

The trend towards high nitro also makes glow engines messy as the run so much richer. Its why i only recommend 5%.

I cant do anything about the fuel consumption figures though. stoichiometric ratios are sort of a fixed limit.

[stu knowles]

For me, the prime reason to go petrol is to stop the damage that glow fuel residue causes to the airframe and finish. It starts and stops there. Touch wood, my models die of old age now but if glow powered more damage is caused by the fuel than anything else. even with a good coat or two of Solarlac over a celly paint finish it still attacks the paint and will eventually find its way into the wood around the engine bay.

I always slightly over prop my engines and have fairly restrictive exhaust outlets - which does loose some power but so long as theres enough power left to adequately fly I leave it quiet rather than powerful.

[Keith Miles 2]

So, judging by the responses so far, we can rule out environmental reasons, then!

Overall, I would have thought that given the choice of electric (perhaps with onboard sound effects!) , glo or petrol, that petrol would be the least favourable option.

Just seems to me that we are killing off engines which use a more efficient, sustainable and environmentally friendly fuel in favour of one that is less efficient, less sustainable and less environmentally friendly just to save on fuel costs.

Like others, and for several similar reasons, I’m not keen on petrol fuelled models so when this apparent “thrift” kills off the glo engine it seems to me that we will be heading ever further towards the electric cul-de-sac.

A self inflicted wound, perhaps?

[Kim Taylor]

I think that with the honourable exception of Laser and maybe Weston UK, glow engines are very much a niche product now. The shift to petrol is driven more by fashion in the USA than any home grown trend.

As we've recently seen, glow engines are being phased out basically due to lack of demand in the USA where they seem to be going electric for up to 20cc types and petrol for the larger models.

Our market in the UK isn't enough on its own to keep a volume manufacturer busy and profitable. Even in China........

Kim

Edited By Kim Taylor on 09/08/2019 11:36:17

[john stones 1 - Moderator]

Petrol ain't much threat to the size glow engine that's been most common, only as you get to the larger models does it impact, lecky is a different story, and I don't believe "thrift" is the main player.

[Nigel R]

The glow market was saturated.

Create a new market (electric, petrol) = keep selling stuff.

[Jon H]

If youtube videos are anything to go by they couldnt give a rats about noise over in the US which helps with their gas addiction. Bit of a different story for us though.

As for cost, its an overstated advantage of petrol. The fuel is cheaper, you use less of it, but the engine was twice the price in the first place. Most of us wont see a cost advantage to petrol vs glow within a decade.

[FlyinFlynn]

That depends on where you buy your petrol engine from Jon....

[Jon H]

Posted by FlyinFlynn on 09/08/2019 13:57:07:

That depends on where you buy your petrol engine from Jon....

not exactly sure i follow. Prices are more or less even at the various retailers

[Scott Edwards 2]

Interesting thread - I have wondered the same thing. For me, 2 Stroke petrols just sound dreadful in models compared to 4 Stroke glow. That alone is worth the extra fuel cost. Plus I love the simplicity of glow, just connect the carb feed and throttle and you're good !

As for glow fuel rotting paint - you're using the wrong paint, or at least the wrong lacquer. Forget Model Shops and Halfords, use professional Automotive brands like Nexa and Max Meyer, follow the H&S regs and nothing will get through that stuff.

As for fuel cost, add up EVERYTHING you spend on aeromodelling including travel (you will be shocked) and the cost of glow fuel is a very small proportion overall.

[Frank Skilbeck]

Posted by Jon - Laser Engines on 09/08/2019 08:44:33:

Posted by Frank Skilbeck on 09/08/2019 08:20:58:

The other reasons is that Petrol engines run cleaner as they run on much less oil, a typical glow engine has 15+% oil in the fuel and a petrol engine around 3% add to that a methanol engine runs around twice as rich as a petrol engine, then a glow engine kicks out 10x more oil.

That is the theory but i have tested our engines on 5% oil without any problem for a whole year and our petrol version are even as low as 1% in glow terms. So far its all been fine. I need to spend more time testing it before recommending it to all but certainly 10% oil is no problem and i really suspect 5 would be where it needs to be.

The trend towards high nitro also makes glow engines messy as the run so much richer. Its why i only recommend 5%.

I cant do anything about the fuel consumption figures though. stoichiometric ratios are sort of a fixed limit.

Agreed, but the majority of ready mixed fuel is 17 to 20% oil, but I'm planning to buy some neat methanol to dilute some 10% nitro fuel to drop the oil content on my Lasers and some other engines. I think the high oil content is a throwback to when castor was the main lubricant, and with synthetics then less is required.

[flight1]

Posted by Frank Skilbeck on 09/08/2019 18:24:26:

Posted by Jon - Laser Engines on 09/08/2019 08:44:33:

Posted by Frank Skilbeck on 09/08/2019 08:20:58:

The other reasons is that Petrol engines run cleaner as they run on much less oil, a typical glow engine has 15+% oil in the fuel and a petrol engine around 3% add to that a methanol engine runs around twice as rich as a petrol engine, then a glow engine kicks out 10x more oil.

That is the theory but i have tested our engines on 5% oil without any problem for a whole year and our petrol version are even as low as 1% in glow terms. So far its all been fine. I need to spend more time testing it before recommending it to all but certainly 10% oil is no problem and i really suspect 5 would be where it needs to be.

The trend towards high nitro also makes glow engines messy as the run so much richer. Its why i only recommend 5%.

I cant do anything about the fuel consumption figures though. stoichiometric ratios are sort of a fixed limit.

Agreed, but the majority of ready mixed fuel is 17 to 20% oil, but I'm planning to buy some neat methanol to dilute some 10% nitro fuel to drop the oil content on my Lasers and some other engines. I think the high oil content is a throwback to when castor was the main lubricant, and with synthetics then less is required.

No need to do that weston have low oil fuel aready done for you see

going to try the 7% in 5nitro on next order

[Chris Walby]

In the big scheme of things the cost of glow fuel is very small compared with the cost of the model, necessary electrical bits (RX, servos etc) and time/effort.

I have had good quality expensive lipos fail in just a few flight risking the model and costing me money. The glow engine (4 stroke) is simple and reliable, follow the manufacturers advice they will probably out live me. And best of all they sound great (even to me when limited to 82dB).

I probably spend more on fuel getting to the flying field than I do flying IC all day.

In the past I raced off road methanol burning motorcycles which included travelling anywhere between Swindon, Midlands to East Anglia and by far the biggest fuel bill was getting there and back!

Electric has its place, but IMHO for a warbird it has to be a 4 stroke IC glow....

[Keith Miles 2]

Thanks for contributions thus far.

I also tend to take the view about overall costs and just feel that while we all like a bargain and try not to waste money it is also about the overall experience which cannot be defined by cost alone.

As somebody has said, glo engines are very simple and, in general, very simple to operate and should last for donkey’s years. Yes, petrol might be cheaper but the engines are more expensive, relatively less powerful and have the added complexity of an ignition system. And I too would have an issue with the smell and vapour associated with petrol when transported in a car plus, of course, the flammability factor.

It’s another circular argument of course with the usual disadvantages and advantages of each power choice being expressed but I suppose that the declining choice is what bugs me and, I would guess, many others too.

On the cost issue and as a PPL holder, I often come across pilots complaining about landing fees of, on average, £12 to £20, or moaning about having to pay anything at all whilst paying upwards of £120 per hour aircraft rental or even, in at least one case, whilst being the fortunate owner of a £500,000 aircraft!

In that context, the cost of glo fuel is certainly not a reason for me to change my preference. Only unavailability will do that and then it will not, of course, be a matter of choice.

We have one or two electric flyers in our club who still harbour some degree of admiration for IC and one of those (who almost exclusively flies EDFs) recently bought a rather expensive glo four stroke which, naturally, prompted more than a few comments from the noisy, smelly and oily minority! Good on ‘im, I say! 😊

Edited By Keith Miles 2 on 10/08/2019 00:02:58