Jon H

absolutely. Matt colours last about a month in my experience, gloss maybe a season. nitro and methanol are nasty and really dont do paint any favours

2k lacquer spray cans are one use only and about 15 quid each. Once you pop the capsule and mix the catalyst you have only a short time to use the whole tin before it sets. For the scaffolding on the back of the ender i would paint the epoxy on with a brush and call it a day as you will use barely any paint and it will be a waste of a tin. You could also stain it a fancy brown colour if you wanted before giving it the epoxy coat. One final thing with the 2k, it might eat whatever paint is under it. So far i have tested it on enamels and to my astonishment it didnt eat them. However, caution is recommended. Give ccr custom paints a call and see if you can order up a small sample pot of 2k clear for testing. I did this before i committed to the job. Oh and i nearly forgot. The 2k activator part has a short shelf life as it absorbs water from the air. Generally its an order, spray, bin the left over sort of situation unless you have really good storage conditions.

if the paint itself is not fuel proof then yes. The topic of fuel proofer has been done to death but the short version is that no single part paint is fuel proof and you need either 2pak/epoxy/2k type paints with a base and catalyst for a true fuel proof job. I wish i knew what YT used on their models as the paint on my 14 year old La7 is still untouched. That said, it was probably so toxic it wouldnt be allowed for sale here. In any case, i have started using 2k lacquer intended for motorbikes and so far the results are good on my test model. Its half the price of the modelling equivalent epoxy based system and easy to get hold of. They even do spray cans. The downside is its potentially very toxic so a decent mask and basic protective equipment are very important. For bare wood/firewalls/fuel tank bays i thin some epoxy finishing resin and paint it on either with a brush or using an old airbrush to get it into a tank bay. This works well for protecting from fuel leaks and it also soaks into all the not very well glued ARTF glue joints. Again though, epoxy vapor from an airbrush is very bad for you so dont breath it in. Once its all on i give a light waft with a heat gun to flash off the thinner and leave it to dry. Works well and it saved my acrowot xl recently when the tang bung gave up the ghost

no i just use standard ones. by who? Not see that myself. I cant recall coming across any when rebuilding other brands of engine, and we never used them at laser

Paint the wood with a thinned epoxy to fuel proof it.

The codes you have are right for an OS 46 if my memory is right, so you are certainly in the ballpark. I always use simplybearings.co.uk and use their budget range without hesitation. I have used them for years and rebuilt an OSFF240 flat 4 using their budget bearings back in 2018 and they are still fine. Using the cheap ones you can get both for under a tenner.

The old laser engines used soft valves and they would eventually wear until either they no longer seat, or they mushroom so you cant get them out. This was a reason we stopped servicing them as the later valves didnt fit and it was not cost effective to make more. As for the collets. Ring spanner and block of wood. I did a video showing how to do it, i just cant find it as i do not have the laser youtube channel password to go and get the link.

im not totally dense you know 😛 but leaning over half the model from behind is still more than a little precarious in my estimation and i do not see it enhancing safety as i have to lean even further over the model. if i learnt anything from a friends efforts with an rcv some years ago its that the starter stick rarely stays where its supposed to it tends to mess up cowls when it leaps out of the crank bolt and dances around. This lead to me nearly flattening said model by falling on it while trying to start it. While i am enjoying the engine i do still think it is a solution looking for a problem and certainly the behind prop starting is in that category as well.

Yep, always investigate dodgy sounding bearings. Still, very strange failure as the bearings look in good condition.

i just crank the prop over. I dont have the doohickey for my starter and it seems like a more dangerous method anyway as i have to lean over the model in a precarious way. It starts fine cranking the prop so ill keep doing it. i will see if i can employ a passer by to film yea i might fit another plug washer to slightly reduce the compression. Mine has stonking compression with my home made ring and its got better with more flying time. Still, once unloaded in the air it sounds sweet so i might just leave it alone.

15x6 for the 80. For the saito to shake its mounts loose in minutes something has to be wrong. I still think the issue is probably with the low end tuning, but even so that is the most extreme case i have heard of. Are the mounts of decent quality? Many artf's come with very flexible mounts which is not ideal. Also how is the engine installed? bolts with nylocs?

RCV update on the RCV thread

Its been a very long time but i finally got around to fitting the rcv into a model. The old Laser test bench wot4xl was dusted off (apart from the dust) and the 120 attached. After more than a year dormant the engine fired up with little fuss and after some tuning off it went....And frankly, that is all there is to say. It just went off without any real bother, pulled the model around and didnt stop. The 5/15 fuel caused no problems, fuel consumption was good, exhaust was very clean with only crankcase oil on the model, it didnt get very hot even without a cowl/baffles, the 20x16 ran at 4000 to begin with but came up to 4200 (8400rpm at the crank) by the 3rd flight. Generally the engine handled well and it was getting better with each flight as my home made piston ring ran in a bit. The engine has a slight crackle on the ground and sounds over compressed, but in the air this fades away. My original plan was to fly it for a day and then whip it back off the model so i could test another engine. I think however i am going to leave it on there for at least another flying session just to give it a bit more run time. All in all i am quite pleased with the results so far and its a far cry from the negative experience i have heard so much about.

Saito are known to vibrate a bit but i am surprised to hear its a bad as you describe. A very lumpy tickover is symptomatic of the bottom end mixture being out (too rich) and in need of adjustment so this would be my first port of call for investigation should you put it back in the model. IF you do, grab a video of the problem as its far easier to diagnose when we can see the issue

Busy day in the workshop leaves me with one finished guitar, one in primer, another sanded ready for paint, and a wot4xl now sporting a new engine in the form of an RCV120 that i am keen to test fly. Once that is done the wot is going to help me make an awful sticky mess by flight testing a PAW60 diesel. Both are engines i have had for ages and have been meaning to air test to get a feel for them. Its likely both will only see one day of flying but that will be enough to give me the information i want.

I agree with the other comments. The TT46 is a good engine, i had one for a number of years and flew sport models with it on an 11x6. For something slow like this i echo the other comments but would go bigger and look at 13x5 as it will not matter at all if you loose a few % of peak power due to a slight over propping of the engine. IF you did want to go 4 stroke then a 50 class engine would be more than enough and again 13x5 would be my choice of prop.

Hi Artto No im afraid all of my model building projects went on hold for several reasons. One was a degree of disinterest in the hobby caused in no small part to working at laser. Dealing with engines and model related problems all day just left me with no enthusiasm for my own projects. I had other problems with nightmare neighbours who would kick off if i so much as breathed, so moving house became a priority, which meant getting a new job, then laser was closing anyway.... long story short 2024 was very much dedicated to getting life back on track after...4 years of difficult times. I have mostly achieved that and i am slowly ticking off my model related repairs and getting back into it all. I have repaired and test flown most models now, with the P39 and Sea Fury awaiting test flights (tomorrow if the weather holds), My small Hurricane needing inspection/service, my Stampe needing repairs and maybe an engine swap..and i think thats it for simple stuff. My DB Hurricane needs extensive repairs due to veneer delamination from the foam wings and my poor Airsail Tomahawk is currently broken into 4 pieces so needs some love to try and rescue it. Once the airworthy fleet is back in shape (long term repairs may be put off until winter) i will be getting back on to my various spitfire projects. I currently have 4 on the go, but that will drop to 2, with a 3rd to follow as i have changed around my plans for the various airframes. I also have some other projects to focus on with a flair pup i want to restore, a wot4xl i want to use for some engine testing, and non model related projects with 4 guitars i am in the process of building, modifying or refinishing. So yea, i best get off of here and make some headway down in the garage/workshop.

I think later saito FG engines have bushed rods as they realised the plain ones were rubbish. The laser petrol engine ran 50:1 on a bushed rod and i never had any fail

yep. ABC or ringed. Even the old iron/steel jobs but with them its important to heat cycle them so cooling between runs is very important Bronze bushes should be fairly stable. Most little ends are plain ali in any case.

why not lower the tank? Its likely a full flip to upright has the tank low now so i would look into its location as you dont stand much chance if the tank isnt in the right place. Always align the top of the tank with the middle of the carb for the best results.

Yea...i must have had a brain fade as i could swear you mentioned a 120 in your post. I checked, and no, brain fade confirmed,

no worries. Personally i was never a fan of this setup, and i dont mean that as a negative towards steve as it does work and work well. My complaint was always that its effectiveness is determined by the quality of its assembly and this is not always a constant given the specific materials used and the skill/experience of the person doing the work. At the time i was in a position where i was having to advise customers, and so i had to give advice that is both guaranteed to work, and gives me a baseline understanding of their installation so i can offer troubleshooting advice. That latter part would be impossible with an unknown and unproven setup like this. Clearly i am not advising customers any more but i still would rather lower a tank as there are just fewer complexities and unknowns. If you are going to give it a try i would recommend building and testing the whole lot out of the model first to make sure it works as you intend. Im guessing the 120 is in a warbird of some type. What ya got? anything fancy?

No worries cuban. One point i forgot was fuel. Much is talked about fuel and oil and blah blah. 5% nitro, 15% oil for any 2 or 4 stroke bog stock fixed wing engine. It will be fine. You need no more or less. Tuned pipes, helicopters, club 20, ducted fan...requirements may differ, but for sport,scale and aerobatic fixed wing normal stuff, its fine. I run ASP/SC, Saito, Enya, RCV, Magnum (the old british one) and OS on this mix, never use on board glow* even on multi cylinder engines and have suffered just one non fuel starvation related deadstick in the last 20 years, and i think that was my fault anyway and not the engine. You also do not need more oil in the fuel for running in. In the latter years after its development i ran in all of the new lasers i built on the new 7% oil fuel (not recommended for saito!). 7% was always my starter for 10 and i intended to continue development with 5% oil being an easy win and a target of 2.5% with further testing to confirm reliability. Alas things didnt work out that way with the demise of model technics and then laser itself, but we use way too much oil and i run '20% castor only' engines on 15% synth oil without problems. I also ran my ASP160 twin (18% oil recommended) on 10% oil for a full season before i ran out of it. As i have said before and the teacher used to tell you at school. Quality is more important than quantity. If you dont have enough oil in the fuel the conrod will seize and fail in 2-3 seconds. Not hours or weeks or 'in 10 years your engine will....something', no, 2 seconds. If the engine didnt seize up almost immediately, you have enough oil. Lower oil and nitro fuel offers improvement in economy and reliability as the engine will run slightly hotter with low nitro and this is good as it keeps the plug alight. I did start to write something about high nitro and its impact but came across an apparent contradiction which isnt one, but its too late in the day to write an essay explaining so we can shelve that for now. *really pants sc400 5 cylinder radial needed onboard glow to prevent it giving up the ghost. That was until i changed the pistons for twin ring laser 75 pistons and the increase in compression removed the need for the glow. That was until it threw a rod bearing for the 5th time and the valves made of cheddar started leaking again. I think the crank pin is under size for the needle roller master rod bearing. This play causes impact loads the bearing cant handle so it breaks up. I should have nicked a PB102 bar end for laser and just made a bush for it...one day, when i can be bothered to rebuild it again.

I dont think this will work with pressure as pressure in the bottom tank will be greater than atmosphere so it will not allow the fuel to flow in from the top tank. Just use it as is and run without pressure, the SC wont mind. My SC (or is it ASP...) 160 twin has no pressure, nor does my enya 155, OS240 and that is to say nothing of my lasers. All you need to do is reset the needles to account for the change.

Not an unreasonable question. I have no real answer beyond a guess that they want to make their parts using standard pitches and threads rather than completely reinventing the wheel. Also 1/8 turn is not an insignificant adjustment. I am pretty pedantic with mine and 1/64 of a turn is not an uncommon level of adjustment for me. An easier method is changing the needle taper and i think OS used to include a 2nd main needle for some engines with a different taper to suit....something, i cant remember why they did it. No you must set the slow run needle early doors as the slow run is better named the 'everything under 60-70% throttle needle'. The slow run is responsible for metering fuel up to around 60 or 70% of the throttle travel so if its miles out the engine will handle horribly. Dont worry about running in. There is a massive amount of paranoia and general hysteria connected to run in procedures and 99% of it is absolutely not required. If you take your brand new engine and fit the smallest prop possible, then start it and immediately firewall it while tuning it for its absolute peak performance...it will be fine. It will not throw a tantrum, or break, or die in any shape or form unless you decide its a good idea to leave it at full power for the next half hour while wrapping it in a blanket to see how hot it can get. I have no idea how many engines i test ran at laser, thousands probably, but every new engine i ran was screaming its heart out within 30 seconds of it first turning a blade. I tuned them for peak performance on the main, throttled back and set the slow run. Each engine was test run for less than 3 minutes, rpm and performance checked, and it was all over, done, boxed, off to the customer. Why did we do it this way? First, heat. Heat is good for your engine. Oils perform better, build up of harmful combustion residue is reduced, and in the case of a new engine especially all of the parts have expanded to their full dimension. Clearly too much heat is bad, but so is too little. Run the engine in too cautiously and very cold the components will not expand correctly and the engine will run in to those in service dimensions. Once you run it harder and hotter later, perfomance will be lost as the parts have worn to fit a different engine in terms of its dimensions. In any case engines should be hot. I would cautiously give a guide of 90-120'c on the head, 70-90 on the crankcase. that sort of thing. Basically if you can touch it but not hold it for longer than a second its probably about right. If you can pick it up and hold it then its too cold. If you can fry an egg.... The next reason was RPM. High rpm at light load is great for bedding in the rings and valves. In the case of the laser specifically the high rpm did a nice job of work hardening the ali valve seats. in the head. Corrosion. Run the engine rich/cold and you leave raw fuel in the engine. Methanol loves water, and you get rust soup in your crankcase. Lubrication. As discussed heat is good for your oil, but running rich is bad for lubrication. The accepted wisdom is that rich means better lubrication as you have more fuel so more oil. Makes sense, kinda, but its wrong. In a 4 stroke in particular, if you do not burn the methanol off it migrates down into the crankcase where it dilutes your oil and reduces its effectiveness. Finally, from the point of a view of a manufacturer, it was important to stress test the engine to confirm its performance and reveal any issues. Like the slow run needle, run in instructions are extremely conservative to cover off the guy who just rags the thing from the get go with zero cooling and the lowest quality fuel he can find. The run in procedure i would recommend for any model 4 stroke on the market is to first take off the rocker covers (all) and cam cover (OS and OS clones only) and give the engine a shot of 2 stroke oil. Anything not an OS or a clone give a good squirt up the crankcase breather instead. Turn the engine over to distribute the oil, then drain most of it out. Pick a small ish prop for the engine. 14x7 for a 100 is perfectly fine and fire it up. Run for about 30 seconds at 3000 ish rpm. open to 5000rpm and remove the glow (adjust throttle to keep the 5000), leave it like this for another 30 seconds. Then open to full power, and tune for about 90% of peak. This should take no longer than 5 seconds. Once you have done this throttle back and adjust the slow run to be half decent. Run like this for about 5 minutes up and down the full rpm range with some short 5 second bursts at full power, and plenty of idle to full power accelerations as well. Once bored set both needles for as close to peak as possible, pinch off the fuel, let the engine cool and have a cup of tea. With that out of the way refuel the model, start the engine and check peak on the main needle. You can now fly the model and use the full power of the engine but use common sense. Dont just peg it flat out and hope for the best, just fly it normally. A lazy aerobatic routine is great for running in an engine as you are at half throttle most of the time, full power up hill, back to idle on the way down, back up to half. The engine gets a full work out but also gets a breather with the near idle throttle setting while diving out of a loop. There are plenty of reasons to do it this way but the headline news is its better for the engine. No dirt or sand blown up while on the ground so debris ingestion is far less likely. Our engines are air cooled and there is more air in the sky...Its more fun to use the engine rather than just look at it...i could go on. A project i always wanted to do was a video where i would assemble a brand new laser engine, fit it to a model, set it up, and then completely wring its neck in the air all in one continuous take just to demonstrate how much exaggerated fuss is made about running in. The short version of all this is that the traditional 'run it in slow and rich while cool to the touch' is wrong. It always has been and the procedure above will work just fine provided common sense is employed. I was actually sent a brand new saito 82 to run in and i used the same method with that. It didnt melt, or explode, and by the end of the 5 minute run it would hold full power for the 5 second burst without sounding distressed in any way while ticking over reliably at 2000. Were it mine and in a model i would have refuelled and flown it without hesitation. Bit of a long one, hope its useful.