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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: Upgrading Windows7 to Win10 for free
12/01/2020 22:35:45
Posted by RC Plane Flyer on 12/01/2020 21:53:34:

I am no expert but of the opinion that Windows 10 works better on newer laptops. I updated a mature Acer laptop to Windows 10 and it took weeks to get it settled down, Replacing it last September with a new laptop with Windows 10 already installed no problems

If its an old laptop the hard drive might be dog slow. A modern machine probably came with a SSD or eMMC flash as a hard drive. Even if it didnt, a modern hard drive is still faster than those from years ago.

12/01/2020 22:33:59

For those looking to reinstall windows/upgrade your hard drive you have a few choices.

You can clone you existing drive onto the new one. As the name suggests its an exact clone of what you have. I use a program called aomei backupper as its free and works well. The only 'hard' part is making sure your new drive is configured correctly as either MBR, GPT or Dynamic. Its not as difficult as it sounds once you know where to go.

After the clone you would then need to update to windows 10. You can do this using the media creation tool (search google)

As an alternative, you can use the media tool to create installation media. You need either a usb drive or a blank dvd for that.

If you choose this, manually back up anything you cant live without onto an external hard drive or whatever. Then tell the system to boot from the usb or dvd drive (you might need to access the bios and change the boot order) and install new windows 10 on either your existing drive (it will wipe it clean) or a new SSD.

It all sounds very complicated but its really not too bad once you get into it.

12/01/2020 19:33:11
Posted by Glyn44 on 12/01/2020 19:07:03:

Just buy a Mac. Easy.

Good plan if you want to pay more than double for the same hardware just for a status symbol.

If you have a windows 7 licence key on the side of your computer then it will likely work with windows 10. I have upgraded at least 10 machines recently with windows 10 using a 7 licence key and it works fine.

If that fails, you can buy a windows 10 key on ebay for about 3 quid.

Once thing i would suggest is that if you do upgrade to windows 10 you also upgrade the hard drive in your computer to a SSD as they are much much faster. Windows 10 loves to talk to the hard drive and all that chit chat slows the system down. As SSD's (solid state drives) are so much faster the constant access by windows is not a problem.

You can pick up a 120 gig SSD for as little as £15 and if you install windows on it, then use your existing hard drive for data storage you get the best of both worlds.

Thread: Which engine ?
12/01/2020 15:36:15

I like that exhaust. I am trying to decide what type to make for the OS300 as well as the 160 and that is a type i have considered so knowing it works well is good to know.

As for muffler pressure i didnt use it on the 300 when i flew it and dont use it on the OS FF240 either. most of my lasers run without it (one exception), my Enya's dont need it and neither does my magnum 240 twin. I definitely think its importance exaggerated and its mostly a bandage to cover up poor tank placement

12/01/2020 12:23:27
Posted by Martin Harris on 12/01/2020 10:31:25:
Posted by Jon - Laser Engines on 11/01/2020 23:36:40:

Certainly is an ASP - maybe a "budget" engine but it's soooo smooth...and sounds superb.

I have an ASP 160 twin as well and is is very smooth running. I have to confess though, the noise on the straight pipes is not to my taste at all. I had the same experience with an OS 300 super gemini but once i fitted a muffler to it then i was sold as it purred like a kitten so i suspect the ASP will be a similar story. Admittedly my engine has never flown as i my friend and i both bought cubs and were going to fly them together. Sadly though, he crashed his before i even got mine out of the box so i sold my model.

Part of the delay was due to me trying to get the engine to run right. Its compression was always poor and the right cylinder always ran rich below half throttle. I have since modded the engine with pistons and rings from a laser 75 and performance has improved. Its still not brilliant though, i might have to make it twin carb or something to fix the imperfections.

11/01/2020 23:36:40
Posted by Martin Harris on 11/01/2020 22:54:24:

Certainly doesn't extrapolate to my 1/4 scale [just under 9 foot] one which weighs around 18 lbs and flies with more than scale performance on a 160 twin...

Is that an ASP 160? if sop they perform much like a decent 120 single so should be really nice. 1/4 scale is 105 inch right?

In any case, i cant fault any of the comments here. Cubs are great fun and dont need massive power. What they do need however is a good grasp of how to use your rudder. Connecting it to the ailerons on the tx is no good as you often need to use them in opposition!

11/01/2020 11:18:56

It would fly on something as small as a 50 4 stroke to be fair. I used to fly a slightly smaller goldberg cub on an OS48 and it was quite happy at under half throttle. I also flew a customers 94 inch cub with a laser 100 and it was well over powered for scale. Cubs fly with their wings not their props so its best not to go mad.

All things considered, i would use a 70 in it and throw something like a 15x5 prop to keep the thrust high and the speed down.

Thread: Stuck piston ring
11/01/2020 11:11:42

I cant disagree with anything thats been said. The only thing you need to try and decide is what is holding the ring.

If its castor then by all means try and rescue it. At work i have used drops of methanol and a sharp tool i have to try and pry the ring gap open but that only works with oil residue.

If you think the ring has rusted into the slot then you might do better to just go nuts and take it out in pieces as a rusty ring will need to be replaced anyway. This was the case on my enya 53 and i asked the chap on ebay to make me a slightly oversize replacement as i had to do some surgery to the liner with a brush hone to take out some light rust pitting.

Thread: What size model?
11/01/2020 11:05:05

Like most i started on smaller models with 30-50 size engines but then moved up to bigger stuff. I remember the first time i flew a friends 88 inch spitfire and thinking 'yup, this is where its at'.

As i mostly fly scale and have a big thing for WWII fighters i have settled on the 70-90 inch span sort of bracket with most hanging around the 80 inch mark. My sport models are 76 and 80 inch as well.

The reason for this is that these bigger models look awesome, fly better, can handle the added weight of retracts etc without getting to heavy to fly, have better/stronger retracts available, are easier to work on, and are not too big to transport and store. I also find that they are not that much more than a 65-70 inch model in cost but offer so much more.

Many people often comment that they cant transport a model that big in their normal hatchback and are surprised when i tell them that in a pinch i could transport 3 80 inch warbirds in a ford focus/vw golf sized car. Its just a matter of careful placement,

In any case, its unlikely i will go much larger than 90 inch as i dont want to be in the position Bob mentioned where i need to make vehicle choices based upon fitting models into it. I dont want a van so i will keep to models that fit in a normal car and i think the 97 inch La7 i have plans for will be the absolute limit for me....unless i win the lottery, then i wont care and can just airlift the things in if i have to

Edited By Jon - Laser Engines on 11/01/2020 11:05:56

Thread: DB Hurricane paint and finish.
05/01/2020 17:31:14

Its been a little while since i posted an update as not a great deal has been going on, at least, not visibly.

Its all been boring stuff like final fitting of fuel tanks, fuel proofing the tank bay and general tidying up of all the construction as well as the usual rinse and repeat of filling and sanding, priming and sanding etc.

Now all of that stuff is out of the way i have been able to add the litho panels to the fuselage side and modified the hatch cover to meet the cowling. The cowl itself has had the exhaust slots cut to allow me to stretch it slightly for a perfect fit.

The wing has been sanded to within an inch of its life and i then couldnt resist shooting it with a can of black spray paint i had on the shelf just to see how it would look. I kinda like it, but i also kinda like the natural aluminium finish i ended up with on the flaps after i finished them with aluminium tape. A polished aluminium Hurricane is really tempting but i dont think its worth it on this model as there is too much to put right on the overall surface finish so i am leaning back towards the idea of a night fighter.

hurri 15.jpg

hurri 14.jpg

Thread: Phone APP for RPM reading.
05/01/2020 17:17:48

Its not ideal as most tacho's are pretty slow to respond and not brilliantly accurate. My tach has gaps in it and would bounce between say 8600 and 8800 as it for some reason cant display 8700. I think 8300 is another gap in its output. No idea why it should be like that but it is.

Also, even with the best will in the world folk will rev chase. I have to fight the urge myself when testing engines at work as i tach every one after tuning to make sure its working as it should. There are days when a batch of engines is really slow due to weather, and the temptation to screw the life out of it for more rpm is immense as i know they should be 300rpm faster than they are. There isnt anything wrong with them, its just the conditions, but i like it when they go fast! More revs engine room and all that stuff.

05/01/2020 15:43:27
Posted by Steve J on 05/01/2020 13:45:35:
Posted by Jon - Laser Engines on 05/01/2020 11:19:30:

Posted by Steve J on 04/01/2020 21:30:08:

I disagree.

Fine, remain ignorant then.

The only difference between how we tune engines is that I use a tacho and you do it by ear. Somehow this makes me ignorant. Do you machine by eye or do you take measurements?

Goodbye.

Great theory, but as i already explained you cant tune with a tacho as the rpm the engine can achieve is not a constant and it very frequently leads to problems. This is not true of manufacturing as the goal is to make everything the same. At the level we are working engines cannot be operated 'by the numbers'. Its not possible to say that you use a given engine on a given prop at however many turns on the needle and it will do a certain rpm. You just cant set engines up that way and over reliance on numbers leads many people down the wrong path.

05/01/2020 11:19:30
Posted by Steve J on 04/01/2020 21:30:08:
Posted by Jon - Laser Engines on 04/01/2020 20:17:33:
Posted by Steve J on 04/01/2020 17:26:55:

Posted by Jon - Laser Engines on 04/01/2020 11:14:23:

Just wind it up, lean it off until the revs drop a bit, come back so revs are restored and hold for 10 seconds. if its happy then get it in the air.

Those of us who don't have particularly good ears do this using a tacho.

Don't tune engines with a tacho as you are far more likely to mess it up.

I disagree.

Fine, remain ignorant then. Its not like i manufacture glow engines or anything.

 

Peter. So much of the tuning information banded about for glow engines is wrong. Your 300rpm rich of peak revs for example is a classic and does nothing but promote all the things people claim they dislike about glow engines. By running the engine rich you do nothing but waste fuel, make a mess, and reduce the reliability of the engine. All that surplus fuel loves to just collect in the crankcase (2s) or intake manifold (4s) and then as soon as you open the throttle it picks all that fuel up and the engine coughs itself to death. Tell me you have never seen that? You also leave more residual fuel in the crankcase after a run and this promotes rusting of the bearings and other components. Always tune the engine for its peak rpm. This is easy to do by ear and is not a long or drawn out process. Any single cylinder engine should take no more than 2 minutes to tune from scratch.

The reason the 300rpm recommendation came in is two fold. One, fuel tanks are often too high so the fuel head changes during the flight causing the engine to go lean and stop. Instead of correctly identifying the fault and moving the tank they just run the engine rich as a bandage. Two, many people dont bother cooling their engines due to bad cowl design and no baffles to direct airflow. In these cases, the engine will overheat and stop. Instead of correctly identifying the problem and fixing the cowl, the engines were just run rich to cool them off. The addition of more nitro was also promoted for the same reason. This is how we ended up with this nonsense recommendation of high nitro for 4 strokes as they run hotter than 2 strokes so suffer more from bad cooling.

When you look into it objectively so many of the rules of thumb we see promoted in model flying are completely wrong and only exist due to misdiagnosis of faults and bodge job solutions. I was commenting on another thread the other day about the 1 in 3 out 'rule' for cooling airflow being nonsense as well. As i work with these engines every day i try and educate people on their operation so they can get the best from them and not suffer reliability problems.


John, nice to hear the 62 is making a revival. Just dont break it as i dont any parts 

As for tuning it, most cases an engine that is too lean will stop. It wont run hot, it will just stop and usually in very short order. This idea than than engine can be flown 'too lean' for a few minutes before it melts is also not true. If anyone has done oxy acetylene welding they will know what i mean. A touch too much Oxy and pop, no more flame. 

If i had the ability to do it i wish i could do a youtube video demonstrating all this stuff. 

Edited By Jon - Laser Engines on 05/01/2020 11:25:12

04/01/2020 20:17:33
Posted by Steve J on 04/01/2020 17:26:55:

Posted by Jon - Laser Engines on 04/01/2020 11:14:23:

Just wind it up, lean it off until the revs drop a bit, come back so revs are restored and hold for 10 seconds. if its happy then get it in the air.

Those of us who don't have particularly good ears do this using a tacho.

No. its not about good or bad ears as the sound is the same. It might be quieter, but its still there.

The rpm drop from running the engine to lean is extremely obvious and cannot be missed unless one is totally deaf. I appreciate that hearing deficiencies might prevent the perfect tune to within a click, but that isnt what i am talking about. If the engine is leaned off until rpm falls off, and then the needle is then opened until full rpm is resorted, and that setting holds for 10-15 seconds without faltering then you are good to go. You dont need the ears of a bat to do this.

Dont tune engines with a tacho as you are far more likely to mess it up.

04/01/2020 11:14:23
Posted by John Wagg on 04/01/2020 10:03:54:

Thank you for the inputs.

I have looked at tacho's but I have my phone on me always so it would do two jobs at once.

Really only for use with 4 stroke engines as I find it somewhat difficult to determine top revs. (a 2 stroke is no problem).

Possibly a proper tacho' would be really useful for electric motors in comparing different props ?

Cheers.

Dont tune with a tacho! Always tune engines by ear as top end rpm will change from day to day. If you got 8500rpm yesterday in the nice cool conditions you might only get 8400 today in warmer conditions. This might lead you to go that bit leaner in search of your 'missing' rpm only to find that its not there. All the while the engine sits there flat out getting hotter and hotter, slower and slower, while you attempt to screw more rpm out of it. it eventually throws in the towel and you spend half an hour fiddling trying to find out what is wrong.

Just wind it up, lean it off until the revs drop a bit, come back so revs are restored and hold for 10 seconds. if its happy then get it in the air.

Thread: ESM Tigercat - powered by Laser engines
04/01/2020 11:07:08
Posted by Peter Jenkins on 04/01/2020 09:32:37:

Jon, I rather think you may the only proponent of equal entry and exit areas. I agree with Ron that exit area needs to be 2-3x intake area, plus any necessary baffling, to ensure good cooling. I think correct baffling is also vital to getting the cooling air where it's needed. Has worked for me on both IC (glow/petrol) and moderately powerful electric setups (using 3000 watts).

Edited By Peter Jenkins on 04/01/2020 09:33:59

i know its the accepted rule of thumb but its not actually true. Its one of those modelling folk lore jobs that is intended to give a system that more or less cant be screwed up.

On my ESM sea fury i have the exact same setup as Ron. I have an upright V twin with a baffled cowl venting though the scale exhaust outlets exactly as on the tigercat. While i have not measured it, i would estimate that my outlet area is about half that of my inlet area but i have no problems at all with cooling due to the shape of the cowl creating low pressure and effectively sucking the hot air out the back. It works so well that if i have not flown the model for a while and some oil has got onto the exhaust can the smoke from this oil is very obvious venting from the cooling outlet as it burns off. Even at idle it rushes out with great enthusiasm.

Its the shape of the ducting and air outlet that is the most important part of a cooling system and the more i think about it the more models i think i have that are barely 1:1 in/out but cool just fine. My La7 and Acrowot XL certainly dont make it, my Tomahawk and P39 are probably closer to even but to be honest i have never actually measured it

03/01/2020 23:22:11
Posted by Ron Gray on 02/01/2020 15:09:50:

Well that’s not going to work, outlet 4800mm2, cylinder frontal area 4800mm2!

it will be fine. The cowl creates a suction due to its shape so you wont have a problem with equal in/out

01/01/2020 22:28:12

Dont fall into the trap of overcomplicating. Forget the thermometer and dont worry about the needles either as the slow run's sound pretty close to right if its not dropping pots at idle. Fire up both engines, bring them to half throttle or just above and leave them there for at least 20 seconds. Up to full power, tune if you think you need to and hold for another 15-20 seconds. forget the tacho, just listen and if all is well then its out to the runway edge, same again. if its all fine just fly it.

I dont care what people say, Its just not something you can adjust and sort out by the numbers. I have no idea what sort of cylinder head temperatures you should be getting and those laser thermometers are hopelessly inaccurate anyway, especially on the bead blasted aluminium of the head. Any tuning changes ay also take minutes to make meaningful differences to temperatures. You will likely find that one cylinder runs hotter than the other on the twins. i suspect the first firing cylinder will run hotter but in all honesty i have never checked it. The engine will probably run 20 degrees hotter in the summer too so any temperature readings are meaningless.

Once the model is flown you may find that in flight one engine, or more likely one cylinder will be a shade rich/lean or whatever. while it can be a challenge to identify which one make every effort to do so and adjust it the moment you land before refuelling and before the engines cool down. If the engine will then not return to full power on the next start let it warm up a bit more before opening the throttle all the way.

In cold conditions it can take up to 5 minutes at full power for an engine to reach maximum temperature which is why this warmup business is so important.

Thread: Laser Engines - Technical questions
01/01/2020 20:50:47

good stuff Frank. I had 8000rpm in my mind but that was for the 70 so 7700 on an old 62? not bad

Cymaz, i had a look and found an old video, looked pretty monsterous!

Thread: ESM Tigercat - powered by Laser engines
01/01/2020 20:27:48

An unusual problem Ron but a friend had something similar with his twin enya 46 powered he111. What we eventually found was that the engines were cooling off during the time it took to pick the model up, walk out with it, taxi onto the runway and by the time he was ready to go the left engine was too cold (it went lean as cold engines do) for it to run up to full power on the correct tuning for flight. Our solution to this problem was to get to the edge of the strip and hold the engines at about half throttle for 15-20 seconds before winding up to full power. Once satisfied he could then taxi out and go almost immediately before the engines cooled off and once we did this it was all just fine.

All that said, i would have expected your idle test to have mirrored your taxi experience.

In any case, dont bother taking the engine off the model as that is where it needs to work so setting it up in the bench is of no real use. My suspicion is that the engine was a fraction lean on the mains when cold so try the 15-20 second run at half throttle before giving it full power. If its still marginal at full power but solid as a rock at 80 or 90% power then just ignore it and fly. You have more than enough power so if the engine is stable at slightly less than full throttle just takeoff at reduced power and once in the air and up to height gently open it up and see what happens. Be prepared to cut it back if it shows signs of distress but i suspect the combination of going slight rich in flight and warming up will sort it out.

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