Force 2t glow engines

[Learner]

4 hours ago, Rich Griff said:

Inverted....🤣 Lol, yeah, no rudder control or forward motion, I like bubbles.....

 

Have a brilliant day chaps, good flying weather...

Not sure anyones read the bit about boat and marine Rich,

Could be fun running a 10 x 6 under water castor or no castor!!

Edited August 17, 2023 by Learner

[Rich Griff]

Hi Jon,

 

One day I hope to own a Lazer engine, and an aircraft to put it in, so would follow your engine instruction sheet to the letter, for my Lazer.

 

Please could you post ( or pm me and email ) the op. Instructions for your smallest motor in production please as I think it would be very informative to me, and others really.

 

May I ask please...

 

Tapered cylinder walls, so when they expand, they go parallel ?

 

Parallel skirted piston so when that expands, the skirt remains parralel, well as parallel as possible ?

 

Tank fuel level drops due to fuel use, even when top of tank level with spray bar/main jet, so fuel level goes down, carburetion goes a bit weak ?

 

Altitude compensation, we don't fly high enough for that to be a worry...

 

Carburation goes a bit weak due to prop wash/windage, a ram effect ?

 

Surely that will happen due to prop wash/windage anyway whether on ground or in the air ?

 

But I realise Lazer air intakes are at the engines rear, may even be updraught ?

 

The Lazer jam jar is filling but oh so slowly.....

 

The force engine I have is a marine pull start version and nowhere near the "start and run in" stage yet.

 

Gunnar have to rig up vice mounted engine mounting, water cooling and some sort of "load", not to mention throttle control, glow power supply and exhaust extraction.....

 

Still waiting on Perkins reply about instruction sheet.

 

If this little beauty should destroy its self whilst running and if i pursued a warranty claim and was asked " did you run it in as per instruction sheet that came with the engine ? ", and I said no, because no instruction sheet came with the engine, no instruction sheet available for the particular engine, how would I stand ?

 

Let's see what force web site and Perkins come up with.

 

Cooled down a bit now and watered, so back on the roof, it's warm up there...hot even, and a bit breezy...

 

 

 

[leccyflyer]

3 hours ago, Rich Griff said:

Don't run the it rich as in mixture, or don't run it, rich ?

 

Awaiting importers feedback for now, library Friday for force's website...

 

Many thanks for all input so far.

It's many years since I've run an ABC  2-stroke glow engine, but I remember that the best gen at the time was, if you are going to run it it, it's vital to let it get up to temperature and not to run the engine rich, as you would have done with the older glow engines that didn't have that construction. The ABC engines always felt very tight to turn over and the idea was to give them a number of short, sharp runs, if running them in at all - certainly not run ten tanks through them on the bench. Most of my clubmates gave the engines a brief running in period on the bench and then completed the running in of the engine in the air - being careful not to overstress it in the initial flights. I only ever used OS, Enya and Irvine engines so can't really comment on some of the budget brands, except to note that the basic principles for running in ought to be very similar - it's about getting the engine up to temperature and working it for a short spell, before giving it a wee break.

[Jon H]

Hi Rich

 

1 hour ago, Rich Griff said:

One day I hope to own a Lazer engine, and an aircraft to put it in, so would follow your engine instruction sheet to the letter, for my Lazer.

 

Not sure if it was your meaning but i have heard something similar a number of times in the past where i am told i have no knowledge at all when it comes to recommending operating procedures for other brands of engine than the one i make. If i misunderstood fair enough, but i would operate a 2 stroke exactly as i described and have set up more than i can count for students when training. 

 

When it comes to our instructions the only important bits are:

 

Install tank correctly

OS F plug

5% nitro 7% low oil fuel (10% oil if home mixed)

Start

Tune

Fly

 

Most of the rest of the sheet is not actually that helpful to be honest but i can send you a copy by email. 

 

1 hour ago, Rich Griff said:

Tapered cylinder walls, so when they expand, they go parallel ?

 

Parallel skirted piston so when that expands, the skirt remains parralel, well as parallel as possible ?

 

Cylinder is tapered, the idea being it straightens slightly when hot. The piston is also slightly barrel shape, although not always. 

 

1 hour ago, Rich Griff said:

Tank fuel level drops due to fuel use, even when top of tank level with spray bar/main jet, so fuel level goes down, carburetion goes a bit weak ?

 

The key is if the fuel level crosses the horizontal plane of the spray bar. If you have fuel above the spray bar it is assisted by gravity. Fuel below is resisted by gravity. This difference is substantial and the middle of tank/middle of carb thing folk often recommend would lead to this transition which will be beyond the tolerance of the engine and it will go lean. If the tank top is level with the carb there is no transition as the engine is tuned to deal with the gravity resistance from the get go and the change in fuel head pressure is within the capability of the engine to deal with so mixture change is almost nil. 

 

1 hour ago, Rich Griff said:

Carburation goes a bit weak due to prop wash/windage, a ram effect ?

 

Surely that will happen due to prop wash/windage anyway whether on ground or in the air ?

 

glow engines are remarkably tolerant of airflow over the carb. Ram air like a 2 stroke, the opposite on a laser, and perpendicular like some of the OS multi cylinders. IT matters not and the engines all go slightly rich as they unload in flight. There are limits to this (pipes, really excess rpm like pylon racing etc) but for general sport and scale flying just get the tank in the right place, tune for peak rpm, fly. 

 

1 hour ago, Rich Griff said:

The force engine I have is a marine pull start version and nowhere near the "start and run in" stage yet.

 

I have you admit i did miss the marine bit. Makes the run it more critical in my estimation as any rich running will have an even greater impact on running temperature due to the water cooling. Never run in a boat, the closest would be my nitro cars with 21 pull start force engines in them. I would start them and just drive around at moderate speed as i needed the airflow for cooling. A few hard accelerations at full power, then off throttle coasting while still at speed did the job nicely. and all on 12% oil too with 16% nitro in the cars for cooling as they did get real toasty. While i would expect something similar i am not exactly sure of the procedure for a boat as its out of my wheelhouse 😉 

 

1 hour ago, Rich Griff said:

If this little beauty should destroy its self whilst running

 

Why would it do that? 

 

I often get the feeling from some of my customers that they are absolutely terrified that the engine will destroy itself if they do anything even slightly wrong. The reality is modern engines are pretty hard to kill and one accidental lean cut or over heat is unlikely to do any harm. In fact i have more customers do harm to their engines running them conservatively as the inevitable result is rust, and plenty of it. Debris ingestion and negligent maintenance are the two biggest killers of model engines and i would put them ahead of crash damage when it comes to engines i deem beyond economical repair. 

 

 

 

[Paul De Tourtoulon]

28 minutes ago, Jon - Laser Engines said:

The key is if the fuel level crosses the horizontal plane of the spray bar. If you have fuel above the spray bar it is assisted by gravity. Fuel below is resisted by gravity. This difference is substantial and the middle of tank/middle of carb thing folk often recommend would lead to this transition which will be beyond the tolerance of the engine and it will go lean. If the tank top is level with the carb there is no transition as the engine is tuned to deal with the gravity resistance from the get go and the change in fuel head pressure is within the capability of the engine to deal with so mixture change is almost nil. 

It shouldn't make much différance if like most of us use the pressure nipple from the silencer.

[GrumpyGnome]

The instruction bit I followed was to start rich and then run a couple of tanks through, not at full revs all the time.  Used an OS plug (isn't F for four strokes?); Weston 10% nitro fuel.

 

I then leaned it out for max revs and then richened it slightly.

 

I'm no expert, but that worked for me.

[Rich Griff]

Wow Jon, utmost respect for you and admiration, what a lovely job you have making the engines you do, top man in my view.

 

I would imagine your experience is very wide, and deep.

 

Buying a laser engine for me would be a very long term investment, purchased to use and use and use, not as an exhibition piece or "bling".

 

When I get a laser, that's when not if, it's will be cherished, a really good bit of British engineering, to be used, so I would give it the best start in its life, by following the instructions.

 

I can't see the wife letting me run the boat in the bath, but she does go to town from time to time 😁

 

Still no reply from Perkins.....they say they like to reply within 8 hours, working hours I think the site said if I remember correctly.

 

Anyways, a real computer tomorrow, lightening speed internet and a big vdu.

 

Will be researching centrifugal clutches, car and/or helo.

 

Jon, did the founders of laser engines visit a bring and fly at lmac at penrhos pwllheli in the eigthies, if my memory is correct ?

[PDB]

4 hours ago, Jon - Laser Engines said:

In fact i have more customers do harm to their engines running them conservatively as the inevitable result is rust, and plenty of it. 

I had this happen to an engine, could you elaborate on what is happening and how to prevent it?

[Paul De Tourtoulon]

33 minutes ago, Rich Griff said:

Wow Jon, utmost respect for you and admiration, what a lovely job you have making the engines you do, top man in my view.

 

I would imagine your experience is very wide, and deep.

 

Buying a laser engine for me would be a very long term investment, purchased to use and use and use, not as an exhibition piece or "bling".

 

When I get a laser, that's when not if, it's will be cherished, a really good bit of British engineering, to be used, so I would give it the best start in its life, by following the instructions.

Maybe Jon could go as an 'undercover Boss', visit a few clubs, then he could give a few lasers away, what would be your 'free' choice Rich, a vee twin ?.🥳

[Nigel R]

4 hours ago, Jon - Laser Engines said:

go slightly rich as they unload in flight

 

Engines run faster in light. In many cases, this actually means producing/developing more bhp than when static. I never understood when the phrase was "unload".

 

Anyway. Nomenclature aside. I always understood the mechanism to be, increased speed = more vacuum = pulling more fuel. Is that right?

[Peter Christy]

Not sure if its the same manufacturer or not, but some years ago I had an AirForce 40-something heli engine (imported my MacGregors IIRC). It turned out to be a fine engine, once I discovered it did NOT like nitro!

 

The instructions were vague, and not translated very well. It was made in Japan, so I assumed that - like most Japanese heli engines - it would like its nitro, and ran it on 16%! WRONG! It was very hot and spitty, and would not tick-over properly. I tried a tank of straight (NO nitro) in it, and it ran like a turbine!

 

If the manufacturers specify 5%, then I would go with that, and no more! If it isn't happy, try it on straight.

 

--

Pete

 

[Cuban8]

Must be 25 years since I've run a two stroke in any of my models, but I do remember many of the old hands bought up on non ABC engines, almost having a fit when they got their first modern ABC type and found it so tight when cold, it squeaked as it was turned over TDC by hand, Absolutely nothing wrong - just different. Probably more ABC engines ruined or lifespan cut short by overly (slobbering rich) initial runs because the notion of running a new and tight engine almost at its fully run in settings was so totally alien in concept for them.

I had a new Merco 35 in the mid 80s and that was horribly tight for a motor with old fashioned iron innards and was clearly not happy when even run massively rich - I recall burning my finger on the head (which smoked) even though the motor had thrown out an enormous puddle of unburn fuel/residue from the exhaust.

Merco had a factory unit at the time in Walthamstow, East London and we lived nearby. I took the motor in for the chap to have a look at and he pulled the motor apart while I waited and  set the cylinder liner up on a machine of some sort and ran a hone or such like through it - all while I waited and no charge. Don't know how it passed final inspection from the factory. Engine was fine after that and must have had dozens of gallons through it (20% castor naturally, as this was 1985) and gave great service in several models. Sorry I eventually sold it.

[leccyflyer]

46 minutes ago, Nigel R said:

 

Engines run faster in light. In many cases, this actually means producing/developing more bhp than when static. I never understood when the phrase was "unload".

 

Anyway. Nomenclature aside. I always understood the mechanism to be, increased speed = more vacuum = pulling more fuel. Is that right?

It's the propellor that unloads, hence more rpm for a given power input - when static the propellor is at least partially stalled, when you get up to flying speed it is more efficient - with the added benefit of lower current draw in the case of an electric motor.

[leccyflyer]

1 hour ago, Rich Griff said:

Wow Jon, utmost respect for you and admiration, what a lovely job you have making the engines you do, top man in my view.

 

I would imagine your experience is very wide, and deep.

 

Buying a laser engine for me would be a very long term investment, purchased to use and use and use, not as an exhibition piece or "bling".

 

When I get a laser, that's when not if, it's will be cherished, a really good bit of British engineering, to be used, so I would give it the best start in its life, by following the instructions.

 

I can't see the wife letting me run the boat in the bath, but she does go to town from time to time 😁

 

Still no reply from Perkins.....they say they like to reply within 8 hours, working hours I think the site said if I remember correctly.

 

Anyways, a real computer tomorrow, lightening speed internet and a big vdu.

 

Will be researching centrifugal clutches, car and/or helo.

 

Jon, did the founders of laser engines visit a bring and fly at lmac at penrhos pwllheli in the eigthies, if my memory is correct ?

Jon was a babe in arms in the eighties. In fact, he was probably not even born in the early eighties.

[J D 8]

 I once had a Cox 15 that was to tight to start, it would fire but then slow to a stop.

Helped it to run with a high speed electric drill a couple of times[ this was before electric starters were generally available] and then it was on its own.

 

[PatMc]

2 hours ago, Nigel R said:

 

Engines run faster in light. In many cases, this actually means producing/developing more bhp than when static. I never understood when the phrase was "unload".

 

Anyway. Nomenclature aside. I always understood the mechanism to be, increased speed = more vacuum = pulling more fuel. Is that right?

Because it's running faster (higher RPM) in flight doesn't necessarily mean that it's developing more BHP. The torque will have reduced & BHP is proportional to Torque x RPM. It all depends on where on the power curve the engine is running at static. 

  

[kevin b]

10 hours ago, Jon - Laser Engines said:

As i tell my customers prolonged ground running is not recommended. The ground is covered in dirt, wind blows dirt and your engine sucks that all down its throat. Model engines are also air cooled, and there is more air in the sky. 

 

Technically the higher you get the less air there is.

I think you meant to say that the air is cleaner the higher you get (until you get to low orbit and then it is full of junk and Elon Musk's satellites).

😉

[Rich Griff]

Paul said "and what would be your free choice rich, a vee twin" regarding a hypothetical freebee from laser engines....

 

For me it would be a cooking model, probably the least expensive engine on the display table, as it would be the most practical choice for me, and I would be extremely happy with that choice.

 

I would not be able to afford the radio gear for the model aircraft for vee twin power, never mind the cost of the model etc..

 

Mind you, two cooking models would be nicer, or is that being greedy, hypothetically of course.

[Jon H]

Just to pick up a few points

 

Exhaust pressure does make the fuel tank to spray bar relationship a little less critical and the overall fuel head pressure more constant. However, it is not a solution to poor tank placement and if you check OS instructions they show a handy picture of an engine installed exactly as i recommend even with tank pressure. They show an air gap at the top of the tank, but who leaves a gap? we brim the tank so the fuel level as indicated in the picture is the top of the tank in reality. 

 

 

4 hours ago, PDB said:

I had this happen to an engine, could you elaborate on what is happening and how to prevent it?

 

The best defence against rust is to run the engine as lean as you can and as hot as possible. So the exact opposite of the conventional wisdom. 

 

To clarify, rust in glow engines is mostly caused by unused fuel in the crankcase. The richer you run, the more unused fuel there is floating around. As we know methanol absorbs moisture and though a long and drawn out series of reactions you end up with formic, nitric and carbonic acid in your engine. So the defence is to run the engine at peak tune, burning as much of the methanol as you can. This will also run the engine at a higher temperature, 80+c. This high temperature helps to evaporate many contaminants and residual stuff in the crankcase. Using lower nitro fuel is also a help here as you naturally run hotter/leaner with low nitro. Its not actually leaner, but the language is messy and inaccurate. we can deal with that another time. 

 

Running engines out of fuel is also a help, but useless if it has run around stone cold and slobbering rich all day. After run oil is usually a waste of time, especially in a 4 stroke as you should only ever have oil in the crankcase anyway (ys excluded). 2 strokes are a little different but 2 or 3 drops of after run will do nothing to prevent corrosion especially if you pop it down the plug hole. 

 

My OS FF240 flat 4 was rusted solid when i got it and the OS blurb makes a big show about it as the engine is more vulnerable than most. I followed their instruction to drain excess contaminated oil from the case (theres a special drain nipple for this) but i dont inject inhibiting oil as they recommend, just run it out of fuel. I have been flying the engine since....2019? and its been fine running it dry and then draining the case. The engine does run hot crammed into an acrowot XL but its tuned up nicely and is a delight to use. All 4 cylinder stay lit without glow support too. I will get someone to shoot a video of it one day. 

 

 

 

On the unloading bit, if the engine revs faster the engine has less load on it. RPM is simply a proportion of power output vs load. Power curves of a given engine complicate the matter but that is beyond the scope of a rather blanket statement of the load decreasing in flight. The lower the load, the lower the amount of fuel needed so it will go rich assuming a fixed mixture. Its slight, but its enough to cover a vertical climb or loop. 

 

as pointed out though rpm is not power, and power is not thrust, but thrust is power from a pilots point if view. To use an example i used before, early spitfires and hurricanes had their performance crippled by their 2 blade fixed pitch propellers. The same engine with the same 1000hp gave better performance at the same revs with a more efficient 2 pitch, and then constant speed prop. So in practice its the prop and not the engine that will often define the performance of an aircraft. 

 

 

[Rich Griff]

Thanks for all the replies on this subject so far including info from Jon at laser engines, all good info for future reference.

 

The shop who supplied the force engine cannot provide much info, niether has yet the importer Perkins.

 

I visited the Force engine website for further info, not finding much help on there, unless it's well hidden.

 

I emailed force engines about the situation on Friday and for a reply this morning.

 

Basically they do not include an info sheet in the box usually, other than the parts exploded view.....what does that suggest I wonder.

 

A big thank you to the chaps that help out with a copy of the info sheet that came with that/those engines.

 

Force did supply a " general" instruction sheet which is shown below. Apologies for the poor picture.

 

I have replied to force stating the need for specific instruction sheet for this engine, as others will be needing the info as well I feel.

 

Let's see how they reply....

 

[Rich Griff]

Force emailed this morning requesting whom supplied the engine as they don't make many marine engines.

 

As to the engine being quite tight and missing instruction sheet, force said they are going to get the "engineers" on the case.

 

GG, thanks very much for the copy of your instruction sheet ( aero engine ).

 

May I ask please, how is the engine getting on please.

 

Good and bad points as constructive criticism please, thanks.

 

Maybe force are going to address issues off missing info sheets in the engine boxes and on Thier website...

 

No where near the starting, running in stage with this marine engine yet.

 

Still no feedback from Perkins about this engine...

Edited August 28, 2023 by Rich Griff

[GrumpyGnome]

My Force 46 continues to be very good - reliable, powerful, easy starting, good throttling.  No issues at all tbh.  Apart from trying to fly my Ruckus through a tree which means the engine won't be used for a while........ 

[Rich Griff]

Thanks gg, much appreciated.

 

Sorry to hear about your tree incident, really hope the engine is ok.

[GrumpyGnome]

Engine seems fine ta - out, cleaned, inspected, carefully turned over - all ok 👍

[Rich Griff]

Thank god for that as it was a new engine.

 

Hope lots of the models remains are salvageable, even airframe repairable, but trees can be very brutal, even to four wheeled tin boxes.

 

May I ask what was the cause of the incident ?

Edited August 29, 2023 by Rich Griff