Small Petrol Engines

[Mark Powell 2]

Ultimate,

Zenoah (a division of Komatsu) Chainsaw engines the lot of them. Others - you can tell them at a glance by their very short front bearing, thus they have a 'stuck on' long prop driver to compensate. Lots of them, but getting less. Tempted, I agree with everyone's cleanliness and low running cost comments. I have not tried one yet but probably will. Fancy the 50cc DA or the 33 or 50cc OS, but expensive and a bit big for what I want.

I will probablt 'test the water' soon.

An engine is an engine. Yes. I lokked under the bonnet of a TVR once. Would get no pleasure in owning such a lash up.

 

Edited By Mark Powell 2 on 03/09/2012 09:54:15

[Codename-John]

NGH engines arent anything to do with MVVS Mark, theyre Chinese

I have one of the 17cc engines and its sweet as a nut, very reliable, powerfull, makes next to no mess and uses hardly any fuel, the silencer isnt very good, but better than a lot of other similar engines on the market

[Peter Miller]

I did not buy it from Just Engines because they did not have them in stock.

However just Engines have been kept informed and have been most helpful and supportive.

They are getting the manufacturers to sort the engines out before selling them again.

[Mark Powell 2]

No. I just thought they might be as they have certain similarities to the MVVS ones andf the Evolution ones made for them by MVVS..

I see the bigger ones, such as your 17cc, have a different carburettor to the 9cc one that Peter complained of. Until I saw Peter's comments it would have been the one I would have gone for as I really only want a little one. No longer.

[Mark Powell 2]

Perhaps JE might have tried testing one before selling them. Or, to be fair, you just got a 'bad' one. There have, as far as I know, been  no other adverse comments. But JE's action  now, to China, indicates otherwise.

Personalli I will stick to makes I know. and have direct experience of, having been caught out before

Edited By Mark Powell 2 on 03/09/2012 10:57:54

Edited By Mark Powell 2 on 03/09/2012 11:00:32

[Peter Miller]

The air from the pump is well known and has been mentioned on other forums.

The carb does work ok without it. The ignitions could be a one off.

Once those things have been sorted it is a really nice engine.

 

Edited By Peter Miller on 03/09/2012 11:04:20

[kc]

The major engine manufacturers will have to do something to sell engines in future. Most beginners seem to arrive with electric power now and experienced modellers are switching to electric quite fast. Petrol seems a good idea with Glow fuel costing so much. But why has glow fuel gone up so much recently? Lack of quantity production due to electric maybe?

[Codename-John]

Oil Kc, the cost of oil forces everything else up along with it

[Ultymate]

Yes the cost of oil will have raised the cost of glow fuel to a degree but as far as I'm led to believe methanol is a by product from the production/refining of petrol then there's the cost of the oil and nitro content within the fuel but how it comes out far more expensive than petrol which is absolutely overloaded with taxation is beyond me.

[Wingman]

Just out of interest I Google-shopped fuel stuff:-

Nitromethane - £43.10 gallon(imp)

Methanol - £8.99 gallon.

Klotz oil - £35.75 gallon

For easy calc if you go 10 gallons of Methanol, 2 gallons of Klotz and 1 gallon of Nitro you end up with a 13 gallon mix about 20%oil 8% Nitro which works out at about £15.60 a gallon - not cheap!

[Braddock, VC]

I was contemplating buying one of these to replace my laser 70 in a KK Falcon, I've seen these fly on the old OS 60 fs exposed valve gear jobs which lacked the power to skin a rice pud so it should do ok there. I was taken aback by the cost - £150. That buys a lot of glofuel for the laser.

[Lee Smalley]

So wingman just ignoring previous posts about the costs of glow fuel you can still buy 5% for about 12 quid a gallon if you run big engines then straight will be fine and even cheaper !! It is not as expensive as some would have you belive

[Alan Cantwell]

run a petrol engine on pressure from the silencer, as mentioned, and would there not be a fireball ???

[kevin b]

Maybe Alan, but you wouldn't need to worry about fire if the tank was nearly empty. It would just explode. Any petrol engine is capable of backfiring if the right conditions are met.

[Alan Cantwell]

it would be the vapours i worry about, and being so close to an ignition source, petrol, and its vapours is a hell of a lot more inflammable than glow fuel,

[Peter Miller]

I rather think that the fine bore tube from the silencer to the tank would act as a flame trap, preventing the fire reaching the tank.

I have seen flame traps in large bore tubes. They consist of a diaphragm with lots of tiny holes in them.

I am sure someone will be able to describe them better with examples.

[Alan Cantwell]

Sorry Peter, but i dont think its worth the risk, having been the victim of a fireball, in this case propane gas, its a bit sore--for quite a few weeks but do try it, and report back

[Frank Skilbeck]

Posted by Alan Cantwell on 11/09/2012 18:35:29:

run a petrol engine on pressure from the silencer, as mentioned, and would there not be a fireball ???

For there to be a fireball you need fuel and oxygen, as the silencer pressure is effectivelly spent air where the oxygen has been used this would equate to an inert gas which wouldn't support combustion.

[Alan Cantwell]

would the fresh air not come from the big hole at the end of the exhaust pipe? the fuel will be the vapour, the accelarant the petrol in the tank, i am not much of a techo, but this pressure idea is making the hairs on the back of my neck stand up, im frikend

[Peter Miller]

In fact, if you think about it. There is NO gas flow into the tank, just pressure.

The maximum gas flow from the silencer to the tank will equal the amount of fuel going to the engine.

[Ian Skeldon 1]

I love all types of engines but have found that they are not really well enough engineered to be worth using on anything under 70 inch wingspan. The reason is the horrible vibrations and the very poor noise reduction of the supplied exhausts.

So before you all rush out and buy petrol engines because the running costs are cheaper, start to think about how much further you will need to travel when you loose your current site, or alternatively the cost of buying expensive after market exhaust systems.

BTW, I love all things IC and I have 5 or 6 Petrol engines, I am starting to favour Zenoah because of the ultra reliable runs from them using magnetos ( I know that they are a little heavier and less powerful).

Ian

[Alan Cantwell]

I, to some parts, disagree, i have operated many many engines in many many models under 70inch, with great results, and with a tweak here, a tweak there, can get them to run reliably , and under 82DB, yes, the standard noise amplifier is pants, but there are silencers with extra chambers, witness the superb irvine range,

i agree about petrols, they may seem quiet in the air, but the noise travels a lot further than glow, but even they can be tamed, but yes, it costs miney for extra bits to shut them up,

[Peter Miller]

WE had a big petrol engine used in the club. The first. I could hear it very clearly 1 mile 200 yards away and I mean very clearly and quite loud.

The owner made up his own silncer which cured the problem.

[Ian Skeldon 1]

Hi,

Just realised that I missed out the word petrol. I meant the use of petrol engines on aircraft under 70 inch span, not all IC engines. I wouldn't be flying very much at all if that were the case.

I think it's a pity that the current batch of petrol engine manufacturers don't realise that with a little more effort, we could have quiet an dsmooth petrol engines for our models and they wouldn't have to be that much more expensive. Maybe the real money is being made in after market exhausts?

Ian

[Alan Cantwell]

now it makes sense and i agree with you