Force Two Stroke Engines

[Keith Berriman]

Yesterday my reliable OS 46AX 11 would not start and just kept throwing the prop off  after three attempts  I put it to one side.  Later at home I started searching for another alternative and it seems the only new ones available are Force 

 

Has anybody got one and any comments please ??

[EarlyBird]

Just Engines have them here

[Don Fry]

Keith, been there, frustrating. 
But, reliable to scrap.  In one session? And hasn’t even hit the ground?
There is an explanation and cure.

 

Fuel, air, heat source. One is out of balance.
 

I would explore understanding the problem your motor is facing.

Force motors might be good. But a reliable OS AX motor, is a reliable AX motor.

I

[Jon H]

Is the engine installed upright? and were you using an electric starter? 

 

If so, and the symptom was that the engine spun briefly on the starter and then came to an abrupt halt spitting the prop in the process my money is on hydraulic lock. Most often this is caused by excess fuel in the exhaust from tank over filling. 

 

That's my shot in the dark!

 

On the op, force engines are ok. Used them in my model cars for ages. 

[Martin Harris - Moderator]

Other than hydraulic locking, the other cause that springs to mind is ignition timing.  This is controlled by the glow plug (and the fuel) so that would be an easy check...maybe the element has distorted or you're using a higher voltage than usual?  Have you changed fuel type?

I did have dealings with a Magnum 90 which was a prop thrower and the easiest way to get this started was to apply the starter and connect the glow while it was spinning - easy enough as it was on a large trainer that I was instructing on (the only pupil I've ever had turn up with a 90!) so no shortage of hands.  No doubt a reverse flick would have worked too.

[Denis Watkins]

I am the lucky one at our patch, as I am the go to test pilot to tune and maiden New models. There have been 3 Force 46 so far, and they do operate with plenty of power as other makes in this popular size. All 3 ran straight off, and minimal needle twiddling.

[Keith Berriman]

Thanks for your responses  and report on my findings.

Engine mounted sideways as all my other three AX are, removed engine and took head and back plate and amazed to see water droplets in the various areas including the domed area of the head. The droplets were the size of a pin head so full  clean of crankcase, head,  cylinder etc rebuild. Go through the normal start up proceedure and bingo 

lovely smooth tick over and straight up to full power. 

Looks like need to check my storage fuel bottles etc. 

[Cuban8]

Never heard of Force Engines before reading this thread and looking at SMC and other retailers, they seem OK to look at and quite well priced. If the company that produces them appears  to make a good job of them (two stroke) then let's hope that they might put out some reasonably priced small to mid-sized four stroke engines that the average Sunday flyer will have a use for. There is certainly a gaping hole in the market with good second hand ASP and SC engines commanding as much as when they were new in some cases and OS and Laser setting (in my view) often unrealistic used prices - supply and demand!

I understand that much of our equipment has jumped up in price for many and varied reasons and this is particularly so with engines.

OK.......Laser, Saito or OS are all lovely motors and many of us have spent our cash on them, but I do feel that there is a threshold around the two hundred quid mark or a little more, when many modellers begin to consider whether to make a purchase or not. The average sport or scalish model that most Sunday flyers operate , say around the 60" span mark would a few years ago, generally need an investment of around the £200 mark to get an ASP or SC four stroke, often a bit less for the sizes below 120.

Not everyone has an extensive disposable income for hobbies and there are those who do have the means but choose not to plough quite a large sum of money into the hobby or decline to go for large, powerful and complex engines that are just way over the the top for their more modest style of aeroplane.

Fair enough when there was a choice to go for top end or stick with the smaller budget option, but now that is no longer possible, it strikes me that we have yet another area of our hobby that could face extinction within only a few years.

I'm only discussing this, as last night I was advising a chap on the various options he had to get going with model flying, after getting the bug from solely flying a sim on his laptop for the last couple of years. The electric trainer option seems to be the best bet for him - possibly one of the larger Eflite offerings with all the stabilisation, auto this, that and the other etc complete and ready to go for around £400 looked attractive.

We did discuss IC, but two strokes were of no interest (horrible noise) and although glow four strokes were to his liking, the cost of a medium size example alone (getting on for £300) for when he was ready to advance onto such a model that could use it, was felt to be prohibitive.

As always, one pays one's money etc.  but if the options are limited, then what?

[Engine Doctor]

"Don't panic Mr Manwarring" there's always an answer. Water is incompressible hence the locking up of your engine. Suggest you dump any fuel that's been opened recently used in that engine and after thorough cleaning of system ,tanks etc start with fresh fuel. Methanol is highly hygroscopic and can absorb large quantities of water from atmosphere. 

Force engines are manufactured by a company who specialised in model car engines. These engines regularly rev yo hi 20k or low 30k rpm so they should know a thing or two about the metalurgy required . Not overly priced either.

[Don Fry]

Keith, the motor has been wet. Give it another run, flat out, if you run it with a biggish prop, do it with a smallish prop, to get it good and hot, to make sure no water remains. 
Glad it’s sorted.

[Jon H]

Those water droplets could have been residual fuel. Normally methanol with water in it goes milky so if your droplets were still clear it was likely fuel. 

 

In any case, glad its working again