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Member postings for Jon - Laser Engines

Here is a list of all the postings Jon - Laser Engines has made in our forums. Click on a thread name to jump to the thread.

Thread: Laser Engines - Technical questions
25/06/2020 08:29:53

Sorry DD but the 45, 50 and 62 are dead and even the current 70 is on the brink as they are just not cost effective to make. Also, while they ran well, our 45/50 were too heavy and too big physically. Our current 70 shares most of their dimensions.

I would like to offer a 50 size engine, but it would have to be a whole new design to make it smaller/lighter and that is not very likely im afraid.

24/06/2020 22:26:19
Posted by Martin McIntosh on 24/06/2020 18:39:32:

Other than less mess, is there any other advantage to me if I used 7% oil, price for instance.

Cheaper, cleaner, better economy.

As for availability its all a mess due to the current drama. Eventually we hope to market it as laser 5 pro, laser ultra clean, laser 5 diet? Not sure, we will come up with some marketing buzz word i suspect.

Whatever we do we need to make it clear that its no good for other engines as i cant guarantee that saito/os etc will be ok with low oil. You can see the problem, some clown uses the wrong fuel, engine dies, rants away on a forum that model technics fuel killed his engine. Its not a good look when the facts of the matter are ignored as it throws MT under the bus.

Im sure we can come up with something.

24/06/2020 16:09:36

The sweet smell from the MT fuel is not the oil but their SICAL Additive. All of their SICAL fuels smell like that to some degree or other. Given that the additive does more good than anything else i am more than happy to live with the smell.

And anyway, it could be worse...it could smell like petrol face 21

24/06/2020 14:02:52
Posted by Bruce Collinson on 24/06/2020 13:09:13:

Jon,

To save me going back miles whilst at work, is there a determinant point/date/age for Lasers to use the low oil fuel? Most of mine are under 3 yrs old but 2 100s and my 120 are nearer 10 yrs old.

BTC

In theory any engine after 1992 will be ok.

The reason for this is that all engines made after 1992 have the same construction, materials, heat treatment etc.

Engines made before 1992 are not constructed the same and will probably not tolerate the low oil fuel.

There are some caveats though. If your engine has been run on castor for a long period and there is an accumulation on the big end of the rod its possible this will impede the flow of oil to the crank pin and cause a failure. This is true of any fuel, but the lower oil fuel is likely to be more vulnerable.

Equally, if your engine has a crank pin that is a bit dodgy due to corrosion or scoring, this too is likely to be more vulnerable.

Will these more vulnerable engines fail? No idea. There are too many variables to be sure. I suspect they will all be fine, but there will always be that one engine where it all comes together and it breaks.

The risk of a problem is very low, and any engine in good condition should not suffer any ill effects. I test run all of the engines i repair on the low oil fuel and they all go like stink

24/06/2020 12:55:37

Good news Gary

We are looking at it as the way forward for our glow range and will continue to review the oil content. I suspect we will end up at 5% eventually and perhaps lower still. We will see.

Thread: Is the hobby dying/dead
24/06/2020 11:20:06

I am not sure how other traders are doing but its been really busy here. Jan/Feb were stone dead, but the last few months have been extremely busy compared to the last few years. I think the high cost of Japanese engines is contributory but certainly its been ok for us.

I know others i the model trade have also been rushed off their feet as idle hands start building models.

Model Technics on the other hand have been slow as people couldnt fly so no one was using fuel.

I think Gary is right when it comes to young members. The allure of instant gratification from electronic devices is very tempting, but it also requires little effort on the part of the parent as they can plonk jr in front of the tv and its job done. On numerous occasions we have had youngsters visit the field with dad to see what its all about only for dad to turn around and say its too time consuming as 'i go to the pub on saturdays, ill get you an xbox instead'. And no i didnt make that up, one actually said that.

There is also the nanny state argument that kids cant buy fuel, knives, glue etc so couldnt build a model off their own back even if they wanted to.

To counter Richards point though, we need to encourage new people to come in to the hobby. If we dont, there is no longer a business case for making any of the stuff we all need. Also, why would we not want to bring new people in?

Thread: Seagull Challenger - First kit Build - First IC
24/06/2020 08:22:23

Yep, bigger models fly better in most cases. Its why i dont really fly any warbirds under 70 inch with most around 80-90. They just work better.

At 62 inch and 8-9lbs a decent 70 or an 80 would be plenty of power. My 62 inch 9.5lb Hurricane has plenty of power on an 80 4 stroke

dsc09542.jpg

23/06/2020 15:39:37
Posted by Gsky on 23/06/2020 14:46:41:

Thanks Jon, that makes sense. im not too fussed about speed and power more interested in getting a good setup for flying and learning the ropes of an IC safely.

i was looking at the 46” Spitfire Mk IX by Tony Nijhuis. i love the spitfire elliptic wings and fuselage fillet but probably the build and flying would have been a but of a mess for a first low wing. probably wont be long until i have one though smiley

46” Spitfire Mk IX

If you want to use one of the TN designs i would recommend the 62 inch version instead. Its not much more expensive but its likely to work better with more room for retracts etc. You get full house of radio and not just 3 channels like you do on the little one.

If you want a small model like the one you listed then there are alternatives like the cambrian funfighter series. These have been around for yonks and are much cheaper. **LINK**

If you think you want to go bigger than a 3 channel hand launch model but not as big at the 62 inch TN spitfire then cambrian have you covered with a 55 inch offering **LINK**

And as a final option, Richard Wills from the forum here also does a 55 inch spitfire kit although im not sure about availability, i will point him at the thread and he can comment himself on that.

23/06/2020 14:03:45

These are great and i really enjoy mine. If i had to give any advice it would be not to over power it.

I know most will slap a 46 or 53 2 stroke in there but i honestly would go for smaller as its not a big model.

Mine is perfectly happy on a 40 4 stroke so a decent 36 2 stroke would be more than enough. The smaller/lighter engine will also be an advantage. As your aspirations are towards scale learning to fly/aerobat a model that cannot fly just on propeller thrust will also be an advantage as, like a warbird, it needs a little more care/planing before starting a manoeuvre as you need to preserve your momentum. If you watch a full size warbird display they usually zoom in fast, do a big loops etc, and then by the end of the display they are down to flat passes and low rolls as the energy has slowly bled off and you dont run Merlin's flat out these days!

As a side note and looking ahead, which spitfire kit were you think of?

Thread: Mooonraker Nostalgia
23/06/2020 10:16:43

I used to have a Moonraker. It was given to me by an old club mate when i was about 13.

I powered it originally with an OS 35fp and then an ASP36. Both were more than enough and it was a brilliant model. In fact i consider it the best trainer ever made as it was very strong and could be made to fly sedately while still being totally aerobatic. It would also bite in extreme cases making it a good trainer.

Shame they dont make them any more

Thread: Adding nose weight
22/06/2020 14:32:34
Posted by alex nicol on 22/06/2020 14:29:33:

The deed is done, 3 bits of 2mm lead sheet formed into shape and epoxied upfront inside the cowl. once it dries I'll glass over it just to be sure

thanks to all

Alex

Dont make it too secure. You need to be able to get it off if you want to adjust the balance after the model has been flown

22/06/2020 10:12:35

How heavy is the model? If the 350g is less than 10% of the overall weight then just ignore it.

Filling spinners with lead is a really bad idea. Bolting great big weights to engine crankshafts is also not brilliant as any imbalance will ruin the engine bearings in short order.

I have to confess, i dont understand the hysteria related to adding ballast to a model. The thing needs to balance to fly, and it needs X amount of ballast to balance...so just add the ballast and fly it. Why such a fuss?

My big Sea Fury is 23 lbs, and 2 of them are lead. The engine/spinner were about as heavy a combo as was available short of a radial, the batteries/servos etc were as far forward as possible, and i built a new elevator that was lighter than the original. That left me needing 2lbs of ballast under the engine to make it balance. I ended up with a 23lb 80 inch WWII fighter with a laser 360v for power. Would i want to be any heavier? not really, would i want it to have any less power? not really, does it go like a scalded cat? ohhh yes :D

Thread: Laser Engines - Technical questions
19/06/2020 08:09:34
Posted by Robert Putley 1 on 19/06/2020 02:58:53:

Hello Jon,

Reference my question re my Laser 80 quitting mid air, I see that your response to my question and my reply have mysteriously dissapeared from the post. So here is my answer again:-

Prop. A Super 14x7 plastic, it is heavy. Plug, OS F. Quitting, intantaneous, running at around three quarters thottle. I have never put a tach to the motor. The last plug lasted about seven or eight flights, the previous one, a similar amount.. The motor has not had that may flights, possibly around fifty or sixty flights. The tank is pressurised, and the centre point of the tank sits around 8 mm below the carb.

Thank you

Why is the engine pressurised? It sounds like the tank position is ok so there is no need for it and we dont recommend it.

Your dead plugs, when they come out of the engine is the coil all smashed up? If so its possible the first plug to die left its coil behind and its bouncing around on top of the piston. It sounds crazy but it can happen and if it whacks the new plug the coil gets mooshed.

Beyond that, will it restart after stopping without refuelling and does it always go after the same amount of time in the air?

Edited By Jon - Laser Engines on 19/06/2020 08:10:26

Thread: la.40 in an Acrowot artf?
18/06/2020 12:49:57

I flew a kit built acrowot on a 40la many moons ago. It didnt set the world alight but it flew fine.

Once you get used to flying with a little more thought to momentum and energy retention you will probably forget all about the reduction in power.

Thread: Post A test model
18/06/2020 09:35:12
Posted by Nigel R on 18/06/2020 09:04:58:

Must it be foam? 55 inch is well into wood territory.

Agreed. Foam models also start getting heavy at the larger sizes in my experience. They also can be a bit floppy vs a wooden airframe.

I would look at the seagull challenger. I was generously given one by a forum member to test my FS40 and its a brilliant little model. I fit it in the car in one piece, but its got a 2 piece wing if you need it. There is also a large top hatch so it could be electrocuted if that is desired.

Its really stable on low rates, lands easy/slow, but its a bit of an animal on high rates.

Thread: Saito 125A
18/06/2020 08:27:30

As Denis points out, engines get hot.

I often get questions customers saying their engine is too hot. I ask how hot is too hot and they reply that its so hot they cant hold on to it after a flight. My reply is always, why would you want to hold it? You dont lift the bonnet on your car and give the engine a cuddle after a run!

As a general guide model engines run at between about 80 and 120'c As such, you really should not be able to hold the engine after a run. If you can hold on to it after a run, its probably running well rich and wasting fuel.

The oil as coolant argument is also kicked about but the amount of heat taken away by the oil is really not worth getting excited about and can be ignored.

I agree with the other comments regarding castor, just dont use it. Laser 5 or techpower 5 are my go to fuels and both work extremely well in saito engines.

Thread: Laser Engines - Technical questions
17/06/2020 08:13:29

I think the cams are ok. Its hard to be exactly sure as its a bit dark in there but the positions look right.

Martin, only the 70 has the pointy inlet cam and we did it because it went better in the days when it was a 45. I have assembled 70's with normal cams both sides and it makes very little difference these days.

16/06/2020 18:05:14

Paul, it might have got a carb upgrade in the mid 90's when it was still supported.

The stroke is 18.8mm so that is where the extra cc went

16/06/2020 16:47:46
Posted by Paul james 8 on 16/06/2020 16:05:40:

Spares for an old Laser.....

I recently acquired another couple of older Laser engines, the smaller of the two is now stripped down fully for new bearings and a good clean (not in that order).

I've clumsily broken one of the two piston rings so wonder if replacements are available.

On the side of the engine lugs is the number 62 and three initials, the bore is 26.4mm and stroke 18 so by my reckoning 9.8533 cc or around .601 cu inch.

If available I'd replace both while it is stripped down.

Any clues where these might be found??

Sorry Paul.

If its a 62 they were discontinued in 1992 and we no longer support them for spares or service. Your only hope is to either make a new one or there is a guy on ebay who offers replacements.

A final option would be to forget it and run it with one. As long as its in the top slot it will run fine.

16/06/2020 15:03:18

4 strokes do tend to cook silicone. It will last a little while, but the bigger engine the less time it last. Anything about about a 120 you would be lucky to get a flight out of it.

If you really need to get the noise down try a 19x8. Im not sure how loud the xoar props are but i am using a 19x8 menz prop on my unsilenced OS FF240 and its really quiet. I only get about 7000rpm on the ground and i would probably expect similar from the 200v.

 

As we are off topic a bit here im going to ask a mod to shift all this prop/exhaust chat to the technical thread and keep this for pretty pictures  

Edited By Jon - Laser Engines on 16/06/2020 15:06:33

Edited By Steve Hargreaves - Moderator on 16/06/2020 21:47:24

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