Jonathan M

...or Southern Modelcraft (new stock of Laser 5% due shortly I believe): https://southernmodelcraft.sumupstore.com/product/5-nitro-laser-1-gallon

I agree.

I don't imagine perfect equality is either achievable or necessary. It's all to do with cost and quality-control. Manufacturing to finer tolerances is presumably possibly in technical terms, but costs would go up accordingly. Cheaper brands might be cheaper because of less expensive processes and/or lower QC standards, and sometimes greater variation between batches. There will always be a tolerance range which is acceptable to a marketplace. Our task is to buy the best we can afford, to understand what's important, and to keep an eye on things, but not to expect perfection.

Just heard back. Yes Southern Modelcraft are very much still in business. Low on stock at moment so currently doing new mixes for glow and diesel, and taking orders by email and phone. PS - they'll be at Weston Park.

I've messaged and emailed Southern Modelcraft - will see if I get a reply.

Had a good couple of hours with the Irvine Tutor this afternoon - alone on the meadow except for herds of curious cows whose close presence made me stop ops for a while! - giving its now slightly less than brand new OS46AX several more tanks, including plenty of WOT. Mixed new fuel (Southern Modelcraft Laser 5) with the last of my old (MT Bekra 5), which for the first time with this engine produced a dead stick, cured by giving the low speed needle a quarter of a turn more open than before. Fab engine! Hand starts very easily. Still playing with props (11x7, 11x6, 12x5, 12x6) and tweaking the model's travels and expos a bit but essentially there. Tutor not as precise as the Gangster 63 Lite, but it's now nicely set up for casual aeros and a great model for buddy-box training.

I personally don't know enough about the science to advise you, except to say that, everything else being equal, one's going to get some variation between brands. Also I wouldn't get too hung up between a reading of 14 and 16 or even 19. The things to look out for are (i) a massively different reading between one cell and its siblings in the same pack, and (ii) if one pack goes massively out relative to the others in the same set.

That's the essence of it - they need to be clear and explicit! Easy enough to reduce unfeasibly huge image files to a more modest size. Preview on Mac's have a simple way of doing this. I typically reduce all my phone camera files to 72dpi and 70cm wide before uploading, but this could go down to half that width and still be more than large enough to see all the detail one needs. I'm sure PCs have just the same quick and easy method. The above image reduced again, now to 35cm, i.e. half as wide again - size now just 400 KB but more than good enough resolution:

14yr old at our club started earlier this year, a natural, quickly got his A, already very skilled flying his foam taildragger (the usual 3s 2200mAh PNP bush-ranger thing with big wheels plus flaps) inverted all over the place, etc. I suggested he look up the B Cert schedule and start practicing that. I let him fly the Irvine Tutor - his first experience of IC and a model with proper weight and presence in the air - which he had no problem with and enjoyed, but will he ever go down that route? Will he ever get a balsa ARTF and fit it out from scratch with an assembled powertrain, let alone build from a kit or a plan for either IC or electric? I don't know, but the likelihood isn't high. The magazine? He's never heard of it. Likely to ever buy it? I very much doubt it. What for? This forum? Never heard of it. Maybe he'll have a look, but YouTube is really his native habitat.

I think most of us are in the same boat. With experience we learn how to avoid pitfalls, but also with that same experience we can find ourselves overthinking things - paralysis by analysis! Sometimes one just has to go for it and deal with any unforeseen consequences afterwards.

Measure the IR at storage charge (3.8v), not when full which gives higher readings. Smaller lipos have much higher IRs than large ones, allowing for variation between brands, age less critical but abuse will be, e.g. some examples from tests I did a while ago: Purple Power 3s 3300mAh = 7mΩ average each cell (range 6-8mΩ) GNB 3s 550mAh = 20mΩ (better than both larger and smaller Overlanders below) Overlander 3s 900mAh = 29mΩ Overlander 3s 450mAh = 50mΩ Hacker 2s 350mAh = 60mΩ Nanotech 1s 750mAh = 77mΩ Radiant 1s 700mAh = 84mΩ Nanotech 1s 300mAh = 133mΩ Volantex 1s 400mAh = 200mΩ

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I've now ordered a Carbon Copy u/c. Will fit it in the normal rear position to see what difference it makes. If bumping along still tips the model over then can later move it forward for tail-dragger. @Nigel R I'm sure my stock of K&S 8SWG would be stiffer than the original cheaper legs, but our patch is rough (cattle and wild pony hooves, and we can mow but not roll it flat) so this model really needs a stiffer solution. @Christopher Wolfe those look like a neat solution, but I'd worry if after a few pull-outs the ply base would start to bruise and loosen...? I've got enough depth in the existing torque-leg block to use a pair of threaded inserts for M4 nylons.

Glad you're going for a 4-str and have found a suitable candidate. On the model side of things, the Elder 40 looks lovely, but I assume you're going to cover the open structure on the rear fuselage as you'll have plenty of fuel residue whishing past.

@Chris Walby thx, looking at Carbon Copy one-piece straight leg u/c's, but tricky to find one of the right dimensions all round (would need to compromise on track-width rather than height), would then screw threaded-inserts into the existing block to take 4 or 5mm diam nylon bolts. Or @Engine Doctor yes, happy to convert to tail-dragger by mounting similar Carbon Copy one-piece u/c at bulkhead at LE of wing, and beefing-up the bottom to take bolts etc. This option would also remove the springy nose-wheel which is also a trip-hazard on the rough grass. Either way removing any kind of spindly torque-spring legs is the way to go!

Yes, it is a torque rod system and the vertical stubs are still secure in the fuselage block. I just think the (budget) original piano wire is simply not rigid enough for the job, certainly on a bumpy patch like ours. Blipping the throttle from stationery or when barely moving, as the wheels (already oversize) encounter a tuft of grass or indent they frequently get stuck and the wire legs simply flex instead, and as it taxis along or gathers speed for a take-off the legs oscillate wildly like a pair of drum-sticks at a rock concert! Hoping the K&S replacements will be more rigid and won't need bending back after every landing like the current soft ones.

I'm looking for a practical solution to a mechanical problem - especially as the model is principally used for training.

Getting a bit tired of the original trike main u/c wires on the Irvine Tutor bending badly and having to be re-bent to correct shape after every landing. Also find the stalk-like springiness makes taxiing on our rough patch a less than smooth affair. Combined the problem often leads to the tail lifting and the model nosing over when taxiing downwind! One option is to replace the whole assembly with a dural or CF one-piece, but can't find anything suitable of the right size (spread, depth and fuselage width). So my immediate next-best option is to make up identical 4mm Ø wires but using K&S piano wire stock instead. Can I expect proper piano wire to be stiffer? If having done this it doesn't reduce the problem significantly, then I'll consider the option of beefing it all up by soldering on additional 3mm Ø wire to form a V-shape for each side - to at least reduce the fore-and-aft vibration when taxiing and on take-offs and landings.

Effectively yes.

I bought a set of four Radiant 3s 3000mAh last summer (from two different sources), found them quite terrible. Essentially got only the same flight times in my Riot as the Purple Power 2200mAh ones from 4-Max, appx 7mins. If I tried to extend the times by 2mins with these then they went right down to almost flat! Gave them away.

Glad you've got it sorted 👍🏻

This might be of some interest - watch from about 6:20 when he starts talking about vibration, later how he wouldn't put it in any ARF model without upgrading engine mounts etc.

Glad to hear it! Lovely looking model.

I think most people understood what Don meant by "one speed" as a description of this model type.