John Stainforth

Do you use a simulator? When I was learning I found a really good way to get more stick time was to use a simulator to more or less mimic what I was doing with the actual model. The Real Flight simulator I was using allowed one to adjust the properties of the computer model until they were very like the actual model.

I agree with you here. All the models I have flown inverted, even those with the CG quite far back, have required a little push on the elevator stick. I say "push, push, push" to myself when inverted. If I get too close to the ground I just push harder. That works well for me.

Looks like flutter.

I think there is a lot of anti-American sentiment being expressed here that is not well-founded. Having been in a southern US model club and several UK clubs, I would say that the general competence level in the US club was very high and that we, in the UK, could actually learn quite a lot from them in practically all areas, from club organisation, to safety and to model flying and set up. All the senior members of the US club were very fussy about the set-up of their models, such as fuel mixes and prop sizes. There are several differences between US and UK clubs; here I am generalising. Generally, the weather in the southern US allows vastly more flying time than the UK, the temperatures are way hotter and the humidity higher, and the noise restrictions less. In 2010, I brought a bunch of planes over from the US to the UK and was very surprised how much less well they seemed to perform here. Several factors were at play: (1) the altitude, (2) the fussier noise restrictions, and (3) the lousy fuel I bought here. The last item I changed out for another brand with similar specifications and the difference was like chalk and cheese - I suspected the first batch of fuel had nowhere near the nitro content stated, and probably none at all (that's when I started weighing and doing volumetrics on the fuel I was buying here to check the nitro content). The altitude and air temperature/humidity difference between here and the US club also made a surprisingly big difference - one that was hard to justify theoretically. I found I could partly correct for that by changing prop sizes by an inch or so. Finally, the US club was not so fussy about the noise limit (there was an enormous shooting club next door, that made such I racket you'd think WWIII had started there, which drowned out the noise of model planes). So everyone took the baffles out of their silencers, which probably gave about 10% more power - and may be one of the reasons why higher nitro fuels worked better there. I personally did lots of tests on different nitro fuels and found my Saito 4-strokes and OS 2-strokes definitely ran better and more powerfully on the higher nitro (12 to 15%) fuels. Another thing that surprised me was that I did not find the higher nitro fuels were more expensive to run; the opposite in fact: they seemed to be very economic. This was a bit baffling, but I think it was because the engines ran at greater power at given throttle settings, so I was probably throttling back more with the higher nitro fuels.

Sorry to spoil the party, but I had one of these and I was underwhelmed. Probably the worst value for money I have ever bought in aeromodelling - it looks like about 20 quids worth.

I think assembling ARTF's is an excellent way to getting into building models. This assembling actually requires as much care as the final stages of building a model from scratch. I found that it would typically take me about 30 hours to put together an ARTF. Assembling ARTF's actually got me back into building from scratch. The more effort one puts into the hobby the more one gets back. This is why buying off-the-shelf RTF foamies gives me very little satisfaction; those in my collection are the models that I have the least respect for.

Six years for a LiPo! Is that common? I've not achieved anything like that.

I've just grabbed a ruler and measured it. Looks like almost exactly 160 mm. That's the absolute maximum width between the outer extremities of the cooling fins.

Bucks-composites, Kingfisher Aviation and FighterAces are amongst the best in the UK for providing glass fibre and suitable resins. Phil Clark at FighterAces also provides very useful advice; and FighterAces are the UK distributors for the excellent, but expensive Klass Kote epoxy paints.

I have an OS 115 alpha - excellent engine.

There were actually two smaller ones: the 46 size and the 65 size. Both look pretty similar to this larger one and the 65 size virtually identical. The 46 was the most fun RC model of its size I have had, flew like a bomb (with OS55AX) and was great on windy days. 65 (with Saito 125, I think) flew more sedately, but nice in its own way. I wish these were still available.

To this tired and lame "thought puzzle" I say R.I.P.

Saito are very keen that one does not "over-rev" their engines with too small a prop: "Over-revving of a 4-stroke engine can cause internal damage to the engine". That might be one of their motives for encouraging slightly rich settings in general. Another reason may be that Saito exhaust pipes tend to become undone and fall off, if you run their engines too hot and lean! The OS recommendation to back off the needle setting by 20 to 45 degrees from the peak rpm setting seems even more extreme. They too are very keen on the user running the engines rich whilst breaking them in. "During subsequent flights [after the long-drawn out process of running in], the needle-valve should be gradually closed to give more power... after a total of ten flights, the engine should run continuously, on its optimum needle-valve setting, without loss of power as it warms up"

Jon, many thanks as usual for your expert clarification. Now that I think about it, I actually do more or less as you say and back off the needle valve from the max revs setting only slightly - and nowhere near the amounts suggested by OS and Saito. The only justification I can think of, for the amounts suggested in the American manuals, is that the Americans used to run their engines with much higher nitro contents than in the UK, which gives a considerably wider range of tolerable tuning adjustment than lower nitro fuels. With lower nitro fuels the adjustments are finer and more critical (in my limited experience).

Jon, should I ignore the advice in the manuals for Saito 4-strokes ("The peak rpm should be obtained and then reduced by approximately 200-300 rpm by turning the high-speed needle valve counter-clockwise (richen)"), and in the manuals for OS 2-strokes (which show diagrams with the "practical best (optimum) needle-valve setting" 20-45 degrees back (rich) from the maximum rpm setting ("Lean")). I've always done this. Or do you mean something else? Also, like Engine Doctor, I do the nose-up test at the start of a new session to check the integrity of the fuel tank plumbing.

Well you are in Good company: Christ Himself got it wrong. He was meant to have arrived also on Christmas day but was (reputably) many months out!

Ha! £300 for an OS40. I see that Leeds Model Shop is selling both the OS46AX and OS55AX for £128 pounds, which I think is a real bargain given the brecciated pound etc. That must be about the greatest bangs for the buck in UK aeromodelling at the moment (and way better than the cost of batteries for leccy models, IMHO).

In the US there is a higher proportion of model flyers who also fly full size planes, so this got discussed a lot. The consensus was that those who flew model planes before full-size were superb model aircraft pilots, whereas those who flew full-size first found model flying really difficult. It was not about them trivialising models, but it really was difficult for them because flying in the same direction as the aircraft is so ingrained that they find it very hard to unlearn that and reverse controls when the model and pilot are facing in different directions. (Unlearning ingrained bad habits is one of the top reasons for not learning bad habits in the first place, in anything.) One of the things that I find interesting is that practically all beginners to model flying fly their models in a very similar way: with vast overcontrolling, and find it much more difficult than they expected (because they are "good drivers", or something). What varies enormously is how quickly beginners come up their learning curve. Youngsters usually seem to learn model flying skills much faster than oldies. This may be partly because many of them are already trained in computer games that require fast reactions.

The situation a couple of years ago was clear-cut. Unless the transmitter has a genuine CE sticker it is not legal in the UK. RC transmitters in the US are allowed a higher power. I was going to bring a couple of Spektrum transmitters over from the US to the UK a few years ago, but did not because I was advised it was illegal.

Don't be so sure. Chuck gliders are very easy to handle and it's surprising how far one can throw them!

I don't think Jon is using the words "cheat" and "lazy" in an offensive sense. Indeed ours is not (ostensibly) a competitive pastime, so we are not cheating others by our own approaches to model flying. What Jon is talking about is "cheating" ourselves, i.e., making ourselves seem more accomplished than we are by using various aids that hide our deficiencies. The ultimate is autopilot that flies a plane very well but teaches us little or nothing about flying.

Kim, Thanks for posting the excellent top and side views. All looks fine. The distance between the tank and the carb also looks fine and rather ordinary - certainly not excessive.

Kim, I am having some difficulty interpreting the relative levels of tank and engine in your perspective drawing. The tank and the red line appear to be angled downwards towards the front, and the engine and firewall give the impression of being set up with a very large amount of right thrust, which (in the angled view, rather than side view) also makes it difficult to tell the relative levels. Maybe these effects are just optical illusions.