Jon H

like JD8, i would be interested to know what issues you currently have. A less expensive solution is very likely an option. As for the 70u, my understanding is they are very fussy and their short time in production would tend to back that up. I have never run on myself but a club mate who had one suffered nothing but problems. Also consider the fact that there are probably no spares for it so if you need a new seal or some other part of the pump you will probably be a bit stuck. While the 70 surpass is also a gonner in terms of spares, its also got far less to go wrong with it in the first place.

I think he lost 2 with horizontal stab failure but i cant remember for sure. I think the engines from the 38 went into the A20 he built afterwards.

Sounds like the barrel or more likely the barrel screw is worn. I have come across this many times and old irvine carbs on lasers were notorious for it. A new barrel screw, or even a custom one made to fit your specific carb will work wonders. I have an RCV 120 that didnt idle well at all and a new barrel screw cured the problem almost entirely. Fortunately i have a lathe to do the work, but even if you dont there must be someone locally who can help.

Is this how you are setting the slow run? If so its not the right procedure. You need to bring the engine to idle, and then firewall the throttle. Normally engines are too rich but they make it to full power. In this case you lean the slow run and go again, and again...until you get to a case where the engine no longer accelerates from idle to full power. This will be a pronounced bog or total cut, and indicates a lean condition. I suspect your engine will bog/cut given how lean it is. Note that the slower you accelerate the engine the leaner you can run the slow run needle and a servo is generally slower than whipping it open with your hand on the bench. I did have a video of me setting up a laser 150 carb but i cant access the laser youtube channel any more so i will have to shoot another one some day.

Slow run needle is too lean. That smooth fast idle is symptomatic of a lean slow run. i assume it wont go any slower if you throttle back?

I think the forum video player is broken as it keep saying it cant find the file when clicked on.

dont try to tune with it. They dont react fast enough to be of any use when tuning and your ear will always pick up changes much quicker. They are good for reality checks though which leads me to.. Thats a bit slow. I expected 9200 out of laser 80s when testing with a 14x6 apc. But if the bearings are dragging a bit that is not a complete surprise. Depending on the model you are flying a 14x7 may offer better performance and i wouldnt use anything smaller than 14x7 on a 90. 1800-2000 should be easy enough to achieve with that engine and is what i would expect from a 90 Did it leave a trail of smoke? I am not normally an advocate for diagnosing engine tuning with your eyes (ears are better generally) but in this case if the engine is running cleanly with little/no smoke trail, bogs on acceleration but also leaves no smoke trail it is more confirmation its lean on the slow run. Heavy smoke trails below half throttle and on acceleration suggest rich. To be fair though, all of this tuning chat is wasted breath until the mechanical side is sorted out. Get the new bearings in, strip/clean/rebuild the whole engine (carb included) and maybe even treat the carb to an O ring or two. Get it on a test bench and set it up, then put it back in the model and set it up again. Why set it up twice? Because it shouldnt take long anyway, and if the engine is easy to set up on the bench with a known setup, but then flatly refuses to behave in the model you can logically assume there is some issue with the tank or plumbing in the model. The bench also has good access to everything, you can see what is going on, check for loose bolts after the run...its just good practice to isolate the engine from the model and get it sorted by itself before adding further variables.

high but smooth rpm idle is symptomatic of a very lean slow run needle. The exploded view of the 91 on the just engines site shows no thrust washer between the taper collet and bearing. The end float is likely down to a clapped out bearing. Oys possible front bearing boss might have either a hairline crack in it or the bearing has spun and worn the case causing the whole bearing to float in and out. I have a saito 45 with this exact problem. As the front bearing takes all of the thrust load any loose fit here will show as end float.

They fly fine on 180 lasers, so any 30cc 4 stroke should do the job nicely. Its an interesting point actually as i have flown two near identical Spitfires from different brands on the laser 180 and they exhibited very different performance. One was a DB spit, 80 inch, about 23lbs i think and with the 180 in the nose. The other was a H9 30cc spitfire, also 80 inch, laser 180, but lighter at 18lbs if memory serves. Both flew nicely, but the heavier DB flew faster, landed slower, and was able to hold on to its energy better than the H9. I suspect its an airframe drag thing and the DB models seem very efficient. My DB Hurricane is hauled along with ease by its 240v, where as my slightler smaller and lighter sea fury from yt needs all of its 360v. In any case, 30cc will be plenty for the spitfire, and 20-21lbs should be your target flying weight.

errr...bad. Glow plug engines do not need constant glow support like this and it can be extremely detrimental to their performance as well as making them impossible to tune. Glow drivers are only intended for use at idle and for starting, so its likely you have simply fried the units by massively exceeding their designed power on time. I recommend you set up the next one so you can switch it off completely, fully tune up the engine with it off, and then turn it back on at the bottom 10-20% of the throttle travel if you need it to keep the plugs lit. My OS 4 cylinder has no need for any glow support once running and i never loose cylinders. My ASP, Enya, Magnum and Laser twin cylinders are the same, and i have never had an issue with the saito 3 cylinder radials either. The only multi cylinder engine to give me trouble was an SC 5 cylinder radial, but it has such a collection of problems its not a great benchmark and it is awaiting another rebuild. I would also make sure you are using the right fuel (5% nitro and 7 or 8% oil in these i think if my memory is right) and then tune it up nicely with the glow off.

I was very shocked to see this news on facebook and initially assumed he had been lost in an accident, but reading on the facts came out. As he and i are more or less the same age it really did come as a shock.

There should be a little button on the receiver that you need to hold down to tell it go into bind mode

That guy also has a gyro on elevator i believe 😉

Straight cut means slow run too lean, stuttering stop too rich. Tweak 1/8 turn and go again. I would aim for 2000rpm on a 90 class 4 stroke as a top end for idle rpm. even 1800 should probably be ok. Dont bother, just crank it with the leccy starter and it will go. If not, this also points at a possible lean slow run.

Flight modes are a variation on the same theme and I can see their utility in this case. I don't think my tx has that ability, but I have never checked for it. One word of warning if you use flaperons with this setup is to not use excessive aileron inputs. This flap mix idea puts the wing maybe at maybe 85 or 90% of its critical angle of attack, beyond which it will stall. If you lower an aileron, you increase the angle of attack on that wing and you may provoke a stall if you are this close to the critical aoa. It's for this reason I am not a fan of flaperons and have in the past cut a strip aileron into separate flap/aileron parts For your extra, if it's coming in like a rocket check the cg, it might be nose heavy. Most kits recommend a very conservative cg and significant amounts of weight can often be removed. I took over 1lb, or just under half of the total ballast out of my db hurricane and I can still stand to go a little more. Don't be scared. Unless it's miles out a tail heavy model is no bother to fly provided you don't also have massive rates. In fact a 'tail heavy' warbird is great as it won't spend it's life sniffing the dirt

I have a 1996 vintage sc radial and the best I ever managed was about 25 flights before mechanical failure. I have rebuilt it about half a dozen times and I am yet to get satisfactory performance from it. On the subject of performance, it's down on your ft310 and even a 300v but is more than twice the weight. I do plan to have another go at getting mine going, and my older version is not as good as the more modern offerings no doubt. But it's still a chunk of change for unknown performance

some have new hair and makeup (blue rocker covers) so that suggests a new run? that has to be a typo. Its only ('only') £1400 on the perkins site...unless.....nope, no collector ring included to make up the difference. Its a typo in my book as all of the other je prices are in line with the rrp perkins list

You can make like easier with an elevator-flap mix. Even if the model has no flaps, you can set up this mix to retrim the model for landing. In the case of the 30-50cc class models i fly, dropping the gear and flaps turns the model into a lawndart as its trimmed for much higher speed and without all that drag of the gear below the c/g. I need substantial amounts of up trim in the mix to offset this. In your case you do not have quite as much of a trim change as i dont think the model you have has flaps (??) but even so, you can set the mix up anyway. The way i recommend you do it is to assign a flap channel somewhere on the radio even if it does nothing. Mix the elevator to it (most tx's have a dedicated function for this already) and set a small amount on the rate to make sure its all working before going for a flight to set it up. When you go for a fly leave the menu open on the tx, and then slow the model down at altitude. IF you know your radio well you can beep the buttons yourself, if not employ someone to beep them for you. Keep adding more up elevator to the mix until the model stalls. When it does, put the flaps up to disconnect the mix. Then knock 5% or so off the mix and you are done. Now, with 'flaps' down the model is perfectly in trim for a speed/angle of attack just under stall and it will now be impossible to stall it on approach provided you leave the elevator alone. If the model is going long throttle back, if its short add power. You should not really need to touch the elevators during the whole final approach phase. Just be careful though, if you dont do a formalised approach with a dedicated downwind, base, final layout and just rock up on final still virtually flat out slamming the flaps down will simply case the model to do a backflip as it will be out of trim. As my glider instructor told me when flying full size, you did the landing about 3 minutes ago, but only now did you touch down. A fully thought out and planned landing circuit broken into chunks where do do things (throttle back, gear down,flaps half, rates high, flaps full...etc) in a checklist type fashion makes life a great deal easier and you can feed the flaps in slowly as the speed comes off. FInally, rates/expo and c/g. I have mentioned before that most models (warbirds especially) fly with excess rates on them. This makes them sensitive in the air so expo is added which gives an undesirable response when trying to land. This is a bit backwards as you need to tame the rates first, and then add expo if you need it. I hardly ever use it as its just not needed most of the time. However If the model is nose heavy, which is also very common, it will need a higher elevator rate to prevent a nose over and this contributes to the whole cycle of events. The long story short here is that the landing is done long before your wheels touch the runway. This can be a few minutes earlier at the start of the landing circuit (right height, speed etc) or it can be the week before back in the shed when you took some lead out and tweaked your setup.

20x16 at 4400rpm. I have a thread on it somewhere here.

Knock at least 10% off all prices for shop prices. Nice they are back though. Prices are...fine? i mean leeds have a 52 4 stroke at £160, which seems decent. They dont seem offensively priced to me, and it will be interesting to see if the material quality has improved at all. It also means i might be able to source a part or two for a lawn darted 160 flat i have hidden in a drawer.

Unusual issue that is most likely caused by over revving. If the engine is held at high throttle in a dive it may over rev and cause the valves to float a little. Not sure what revs you are getting, but you could try a bit more prop, favour 4 thou not 2 on valve clearance, take it a little easier in a dive etc. If you are really worried you can shim the head off the liner a little, which will rob a tiny bit of performance, or take a burr and gently modify the piston. If you do that be sure you remove any and all sharp edges or tool marks as you risk fatigue cracks if you dont. The twins run more advanced timing than the singles so are more prone to this happening but its pretty rare. Unless it happens alot (this damage could have been from only one instance in one dive) its not going to be a problem.

I had a similar experience with my two RMX 40's. I changed over to twin ASP52's in the end. Although i am yet to fly it, i have been experimenting with an rcv120sp and believe half the problem is the props rcv recommended. To me, they had insufficient pitch and my testing so far seems to back up this idea. Once i get back to flying again i plan to fit the 120 in an old wot4xl and see how we get on. If you decided to experiment with yours use a minimum of 12 inches of pitch...something like 18x12 or 16x14 would be my choices after a little napkin maths

RMX40 2 stroke. Just trash The OS LA series. Liners fell apart after about 2 minutes. Never owned any, but all 2 stroke petrol engines as the sound is offensive 😉

Ohh diesels have been added. PAW149. My first new engine and it taught me a massive amount about engines/how they operate, tuning etc. AM10. The little thing just sings, and that is really all there is to it. I would love to add an AM15 to my collection. I keep seeing them nib at the bmfa auctions but never seem to remember to actually buy one. I have PAW60 as well, a beast which i need to fit into a test model and thrash around for a bit after its rebuild. I have some DC sabres, which are nice n all but i find them rather unrefined vs the AM. One also has a stuck contrapiston so you can only back off the compression so far. After a minute or two running it gets a bit hot and bothered. I will fix it one day.

This could take a while... To keep it simple my Laser picks are the ones i always enjoyed test running the most: The 80, almost a match for many 91's and solid as a rock. It was the most underestimated of the laser range in my view. The 100 and 180 just worked, no matter what, they just worked. 240v...16x8, 10000rpm...Loved it. 360v, 20x8 over 8000. so much grunt but so easy to handle. 200 and 310 flats, the 200 inline and the very rare 310v were also great fun. I am yet to fly a 310 flat as i dont have one, but seeing Ron's at Buckminster was very impressive. And i cant forget the 155. My first design for the company and they always seem to run well. Oh and frankensteins flat twin prototype. The most hilarious heap of trash i ever put together but it ran perfectly anyway. OS now. OS FP series was brilliant and just got on with life without any fuss. I had 15, 20, 25, 30 and 35's over the years. All worked very well. My OS91 surpass was my first 4 stroke and it too is fuss free. Never owned one but in my brief time testing one the OS155 impressed me My OS26 surpass is just too cute not to like My utterly trashed FS40 (see thread on the forum somewhere) that was nearly scrapped but i was able to save. The big hitters for me though are the 300 super gemini, and my FF240 and 320 pegasus flat 4's. I have plenty of time on the 240 in my acrowot xl and its just faultless. A bit oily yes, but i dont care, its a wonderful engine. I keep looking out for an IL300, but they are rare as hens teeth and have a price to match. Saito. Only 1 here, and that is the trusty 45 in my flair nieuport. Its probably as old as me, massively over propped (15x5!!) but it cares not and is quieter in flight that some electric models. Just a perfect match for the model. ASP The 36 and 52 2 stroke really stood out to me and were great engines. I enjoy my FT160 as well although i have tinkered with it. Magnum (The british one) Left field entry is my magnum 240v. Its an unbalanced, unrefined, underpowered and generally hopeless heap of an engine, but it love it. It shakes, it rattles, and oil pours from every part of it, but its reliable (ish, i have to work my voodoo at times) and i just enjoy the ludicrous theatre of the thing. Enya My 120-4c was bullet proof and great engine. I am a huge fan of the VT240 as well. I also have a 155, which is so savage i cant keep it running for long as it has destroyed every exhaust i ever fitted! I am sure i have missed a bunch, might be a round 2 later.