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Jon H

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Jon H last won the day on April 5 2023

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  1. Frankly, i would use bolts and nylocs on everything. There is simply no reason not to
  2. If its a small piece of dirt a clean air line in the glow plug hole and the valve held open can work, but its a bit of a bodge. If its oil soak it in fuel, depress the valve and then slip off the stem so it snaps shut. Do that a few times and see if stops leaking.
  3. Jon H

    Idle issue

    All standard engines are the same. 2 stroke, 4, any brand. The symptoms of lean/rich are identical in all cases. Rich you see a fast stuttering (more obvious on a 4 stroke) idle with erratic rpm which you cant slow down any more as the engine will cough to a stop. Acceleration will likely be poor/stuttering and/or the engine may stop. Again inverted 4 strokes are vulnerable to rich cuts as excess fuel pools in the long intake header and is picked up but the increase in airflow when the throttle is opened causing the dreaded cut a few feet into your takeoff roll. Lean you see a fast smooth idle with fairly fixed rpm which may then run down over time to a complete flame out rather than a stuttering stop. Acceleration usually leads to bogging/lean cut but sometimes the engine will still pick up well. The overrunning when throttling back to idle is also a fairly common lean indication, especially on a 2 stroke, although it can also indicate an air leak.
  4. Jon H

    Idle issue

    The slow run is too lean judging by your description. If it were a rich cut as Andy suggests the engine would cough a splutter as it slowed down. You describe a lean cut where the thing is running smoothly but then just flames out completely. I would open the slow run 1/8 turn and see if its any better. If it is you have your answer, if not, you still have your answer and you just need to do the opposite of the thing you just did to make it worse.
  5. Knowing the high standards the BBMF work to this is extremely shocking news.
  6. No its fine, and frankly it saves me a job, but only if i dont have to do the job twice as the customer made a dogs dinner of it due to lack of formal instruction on how to do the work. Sadly it will all end up on my plate however i slice it up so i need to either do it myself or come up with a plan you guys can follow. On the rust thing, its the methanol that actually does the damage due to its propensity to absorb water. Its worse in high nitro engines as they do not burn as efficiently and so larger amounts of methanol are left over after a run. To be clear, nitro is not great either, but its the methanol that really kicks things off and as the methanol is dissolved in the oil, it makes no odds what oil you use as the oil is contaminated with methanol and water so it still rusts out.
  7. ill add my 2p in this instance to save a guessing game. Steve, the clattering sound is likely the issue that requires the upgrade part. The engine is also pretty rusty by the look of it and i have seen 3 inline's now that have rusted heavily. I do not know why this should be as i deliberately tested this. To do so i left one of my test engines in a damp shed for about 18 months and while the outside had rusted/corroded heavily, it was immaculate inside. My only thought is my tuning being more accurate, and customer engines are running rich, but this dosent quite add up to me as an explanation and i can offer no other ideas as the one flown in my ugly mustang also seems fine despite a winter in a different damp shed. My suggestion is to contact Geoff and return the engine. Once the new bits arrive i am sure i will receive a summons to sort it out. I would not recommend further running until its been looked at. As for the idea of sending the parts out and doing the work yourself...sure, i guess so. But only if i can work out a procedure to do it without completely dismantling the engine and loosing the cam timing for the front cylinder as i dont fancy trying to explain how to fix that mess when they all fall out on the floor. I will have to check my cad drawing notes to remember how to do it myself at this point.
  8. One thing i would recommend are some decent sunglasses to aid the eyes if vision is one of his concerns. There are days when the glare makes it impossible but normal sunglasses just make the model an indistinct black blob. I used some polarised jobbies with only a mild tint, sadly cant recall where they came from, but they can make a world of difference. Beyond that its difficult to say. I have taught plenty of kids that age, never had an issue like that. But, none of them were my kids (i have none) so maybe that had in impact? From my own experience learning to fly i remember a time about the same age when i felt like all was lost and i was never going to learn and a really awful takeoff leading to a crash really knocked my confidence. I dont remember exactly how i got over it, which isnt helpful i know, but i do remember that i ended up with a few models which were mine only, dad never flew them unless he was helping me. If you already operate that way that is probably not helpful, but if not maybe ask him what model at the field he likes, and pick something that is a suitable stepping stone in that direction. Let him build it, understand how it all works etc. Maybe it will help? If you already do all this then fair enough, but its all that comes to mind immediately.
  9. Both are great models and fun to fly. My dad taught me to fly using his pup as it was all he had at the time. I have the flair nieuport and i hope to take it out to play in a few minutes. Something to watch on the pup is not to over power it. They are very lightly loaded and fly much slower than most are used to. They are also quite draggy so to fly them at 'normal' speed you need lots of power. This leads people to fit 70's as they feel a 50 class 4 stroke is not man enough. It is, a 52 surpass for example is more than enough. Its just a case of getting used to just how slowly they will fly. I have a battered pup waiting for rebuild and a battered engine that has been rebuilt waiting to go in the front. Some day they will fly again.
  10. I dunno seems to be to me. But thats fine as i can respond in kind. There are people who know a great deal about engines and the way they operate. That's fine and you will note i do not tend to disagree with them as they make informed comment on such matters. You however are not one of those people and so we disagree a great deal as most of what you say is flat out wrong and you refuse to accept that i know more about it than you do. Your posts show a clear lack of knowledge when it comes to the operation of these engines and you create flawed conclusions from this lack of knowledge. Your comments some time ago stating you could hear the engine seizing were a prime example. You said you heard it go so landed quickly to add castor to your fuel and solve the problem. As i commented at the time this was a complete load of nonsense as an engine seizure is done and dusted in fractions of a second with no way to stop it, let alone land and reverse the effects. Clearly you do not understand what actually happens when an engine seizes, and what you heard/saw was likely something completely different. In your post you talk about running a model shop, which is great but does nothing to qualify you as an engineer. You say synthetic oil destroyed your bearings, im sorry but it just didnt. If you used an appropriate oil for the job, they would have been fine from a wear point of view. If they rusted out, that has nothing to do with the oil anyway. As for the rest, having the guys from model technics as friends of your brother is also not enough to qualify you as a chemist. Anyone can mix liquids in a jar, but which liquids and why is a whole other game. This is why i worked with the guys at model technics when we did the first laser fuels as i am not a chemist, but John was so i was happy to accept his advice on the matter. And great, the factory was next door. I live near a road but know nothing about how to build one. Competition flying...yea ok, how does that have anything to do with engine design? Lewis Hamilton is a great F1 driver but he's not qualified to design the car. Pylon fuel i believe is standardised world wide, and the fact that its still 20% castor tells me that the regs have not been updated with the times because, again, event organisers and rule makers are not engineers. Also, give the niche nature of the event its not really relevant anyway. SO whats left? gummed up bearings are finished and not protected. You can never get all of the polymerised oil out so you need to bin them and go again. Laser valve springs are not a weakness and never have been. They fail usually due to rust causing micro pitting and then fatigue cracks form over time. This is not helped by modellers draining the oil from the rocker cover because they didnt know there was an oilway designed into the engine causing oil to be pumped into the rocker cover. They didnt know enough about what they had in front of them so came to the wrong conclusions. The only exception to this spring thing was a dodgy batch back in 1998, and they broke all the time. In any event, i have only ever broken 2 laser valve springs, both on 2nd hand engines from the late 90's. I have also broken 2 on an OS91, 1 on an Enya 155, and i think one on something else but i cannot remember what. In any case, its no worse on a laser than on anything else. So im sorry Paul, you just dont know what you are talking about when it comes to model engines and their operation so cannot come to accurate conclusions when faced with problems. No doubt there will be outrage from some quarters regarding this post, and thats fine as my comments are still perfectly valid even if people dislike them, or me. To be clear, my problem is not that someone does not have the level of expertise and training i do in this subject, my issue is when that person continues to assert that they know best when they clearly dont. Unfortunately this attitude is very common in modellers and its one reason i am extremely glad i am no longer in the industry. To this and the rest of your post, correct for the most part. Although most synthetic fuels have corrosion inhibitors in them they are useless if the engine is left with methanol in it. No oil will help you in that instance and i have seen many a castor run engine that was rusty as an old nail. Equally i have seen synthetic fuelled engines gleam like a jewel despite many years of inactivity and no additional after run protection. Generally though you are quite correct and i have heard many times that 'my mates merco was killed by synthetic oil back in 1983 and ill never use it again'. As you mention, there is oil, and oil. Not all are equal.
  11. This is just rubbish. In the old days synthetic oils did not have the thermal tolerance of castor. Now, they exceed it. The idea that synthetic oil 'burns off' is probably 40 years out of date at this point and like castor oil itself, it needs to go away. As for the rest, adding a few % castor to a synthetic oil fuel will not produce the same carbon as a pure castor fuel, but the castor is inferior to the synthetic so you just made your fuel worse for no reason at all. And although the carbon build up will be slower, it will still happen especially in a 4 stroke. Ask my Enya 120 how i know this for sure... If you are 2nd hand shopping do not buy a Laser 45, 50, 61, 62, 75, or 90. They were discontinued in 1992 and there are no spares at all. A modern 70 will have spares when my former employer does the run and sends them to Model shop leeds. If you do look at a 2nd hand laser, post a thread here with a photo so its identity can be confirmed before you dish out the cash. Beyond that, if you can find an OS 70 surpass they are good engines. No spares for them either these days but generally they dont need them unless you lawn dart the model so...dont do that. Saito i think did a 65 and 72, enya did an 80 but they are rare beasts indeed. i would be wary of a 2nd hand ASP or SC these days unless its cheap. with cheap in mind If you want something for tinkering check out the bargain bins at model shows. Many engines have ended up there and prices can be very low indeed. Low enough that you can afford to blow another £20 on some new bearings (they will need them), have a crack at changing them, and still not feel cheated if the engine runs like a dog for some other reason. if there are multiples of the same engine all damaged in different ways a bitsa engine is always a possibility. I suffer emotional damage and bouts of uncontrollable rage watching youtube 'experts' talk about engines. Having worked for 13 years building and designing model 4 strokes i just find the videos painful to watch. Most of them havent a clue and just spout the same old modelling folklore nonsense we have seen for decades. Most of it was wrong from day one, and the rest is wrong because its now out of date. Like castor oil for example. While i am sure their efforts are mostly well intentioned and they simply do not know their information is wrong, a few will always be resistant to change and will continue the old narrative almost out of spite. In any case, while i applaud your efforts to research and learn you do risk being mislead by clueless halfwits who look professional with their flashy video, but the actual content is lacking. I am not trying to dampen your efforts to learn, but to be honest the best thing to do is just crack on and fire one up. 4 strokes offer little in the way of mystery and their operation is functionally the same as a 2 stroke from a user experience point of view.
  12. Time for a little history. In the dim and distant past before they invented colour, bean juice (castor oil) was used in engines as a lubricant. Up to 30% was not uncommon for model engines in those days and castor was a very popular choice. This popularity was for good reasons. It was inexpensive, easy to get hold of, and did a good job as a lubricant. It was also quite viscous which could be an advantage if the fits within the engine were a little suspect as it gummed up the gaps. Crucially, it was better than synthetic oils of the day. Just ask the Germans in WWI. However, castor also makes a dreadful mess and leaves carbon/varnish all over the innards of your engine. The goo on the outside can also gum up cooling fins as dirt and bumble bees get suck to it, exhausts get blocked, and its prone to setting solid leaving your engine totally locked up. It is also a natural product and so its performance will always vary. As a result, you need more of it to guarantee the required lubrication. Fast forward to today and we have synthetic oils which are assembled molecule by molecule using computer controlled voodoo. Engines are made from vastly superior materials and with much tighter tolerances. Since the 90's 15% synthetic oil has been all you need and frankly even this is excessive with 10% probably a more realistic figure today. It always causes a row as not everyone has moved with the times but castor is a dead lubricant now and best forgotten. As they used to tell you at school, quality over quantity. When i was working at laser i did experiments with oil content. This was an offshoot from petrol engine work i was also doing. The petrol engine was running at 40:1 (2.5% i think that is?) at the time, so i wondered if a glow engine would work on that. I mixed up methanol and oil at the same ratio and left it running at 75% throttle for an hour, when it finally ran out of fuel. I then flew some of my own engines on 5% oil for a few years, this was no bother, and then introduced the low oil fuel at 7% to give a big improvement over standard 15% oil fuel, and give room for improvement later. Some customers have run their OS engines on the low oil fuel and had no problems, but i havent tested that so its on you if you have a go and it fails. Frankly, i think OS's would be fine, but as i dont fancy getting yelled at when someone kills their prized motor its not a recommendation from me, but 15% is fine for everything. If you stick to 15% oil, which you might as well do unless you have a laser, you can clean up your exhaust residue significantly by tuning the engine for peak performance and nut having it chuff around half a turn rich of peak and with a slow run needle set so the engine is on the verge of hydraulic lock. Always tune for peak performance on both needles.
  13. as with all engines, top of the tank - centre of carb (or venturi in this case)
  14. It would not be my first choice as flooding will be a much bigger issue with the engine inverted. The tank will also need to be almost under the model and not in it, which is not ideal. If mounting upright is out of the question then a side mount may offer the best option.
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