Martin Harris - Moderator

Thanks Phil - very kind offer. I’ve been doing some further testing and tried loading a different software - nRF24L01pScannerOled_RFNano and noticed that it functions OK while the Nano is powered from the programming port. I’m not sure how to identify the Nano - there don’t seem to be any markings. It seems to point to the way it’s powered but I’m sure I’ve followed the instructions (battery negative is connected to GND on the other row of pins). Please excuse the dodgy soldering - this was just quickly knocked together to confirm operation before I mount it in a printed case…

This thread was created from a sub discussion prompted by this post in another topic. The scanner was designed and programmed by Martin Round (Ceptimus) Seems like a great idea - I put one together today but I'm missing something (no in depth knowledge of Arduino to help me) and although it seems to have loaded the sketch, it doesn't seem to function as I'd expected - nothing past a "front screen". I'm using the 1.3" OLED - should I have modified any code? The notes suggested it was just a case of uploading the sketch as downloaded... Temporary test wiring

🤣 It was filmed during an open day - normally the fencing protects the pits and car park from errant models…our field topography precludes locating them further away…and this was filmed by someone standing in the viewing area (pits during normal operation). You’re certainly not wrong about the fun! Wasn’t yesterday a lovely flying day…and the weather seems set for several more like it!

Arrows Hawk formation (loose but improving) flights are one of our favourite activities - many of our regular flyers have them (and likewise Durafly Vampires) and we rarely have a session without at least 4 flying. Frustratingly, we've never managed to get more than 8 in the air together to emulate the full formation. The more the merrier, of course, but I don't think any of us can claim not to have flown the "wrong" model at one time or another for a split second or so - concentration has to be absolute! I really can't praise these little foam wonders enough - they really can cope with almost any conditions and I think I can honestly state that no week has gone by for at least a couple of years when at least some of us haven't flown them. Open Day Hawks.mp4 Video from a while ago...

What I have noticed, even between chargers from the same manufacturer, is quite a large variation between readings. Don’t expect to compare results with values quoted by others but the main usefulness is comparing individual cells and watching for trends as batteries age.

Just a reminder that the forum conditions do not permit political posts, whether well intentioned or otherwise.

Welcome to the forum John. I've made some changes (and assumptions) to the title and moved it to the relevant forum board. Please advise if is not the free plan from the June '22 issue of RCM&E that you're building from.

No doubt they would either say to calculate it at ICAO standard atmospheric conditions or alternatively at the conditions at the point of launch. The point is, someone has made the decision to specify mass rather than weight - not something that a non- technical author would be likely to consider. I suppose the correct answer is that if you’re contemplating building an aerostat with a potential mass in excess of 25kg (not much over @ 3m spherical), you should consult the CAA for guidance.

The point I'm trying to make is that while the balloon is lighter than the surrounding air, it still has considerable (particularly in larger sizes) mass. The CAA have chosen to require certification for model aircraft exceeding 25kg mass, not weight. It's not as critical to the OP as I'd thought before revisiting his first post but it's something builders of larger model balloons (>3m diameter) and other aerostats might not have considered. Apart from the potential for the momentum of significant mass at any speed to impart damage, it might be that the CAA actually considered mass as being an effective means of limiting the size of lighter than air models while being a close enough approximation to equate to practical measurement of conventional models' weight in normal operating conditions.

I missed the original dimensions so admittedly this one has a lot less mass than the example I was working from. For a 4 cu m envelope, we are now talking about 141 cu ft so this brings the mass of air in the balloon to around 11 lbs but as the mass will expand cubically, should you go much larger, you'd soon hit 25kg. The maths is above my pay grade (well what I can be bothered to work out) and gets complicated by the different air temperatures but I'd guess the worst case scenario is a bagfull of runaway air descending at not much above ambient temperature after a runaway. Whether this was the intent behind the CAA specifying mass rather than the more easily measured weight isn't known to me...

The bag may weigh 9.4 lbs but in use, it's filled with air. I was using an on-line calculator but it appears that at standard temperature and pressure, air has a mass of 0.07967 pounds per cubic foot. 0.08lbs x 2500 = 200lbs so my estimate is in the same ball park. I don't know how much it changes with temperature but I was told many years ago that the mass of an average full size hot air balloon equates to that of a brick built house - one of the main skills in ballooning is to anticipate the considerable effects of vertical momentum in timing the burns - you have to stop burning long before a descent stops and start a burn before a descent is apparent or you'll be bouncing up and down like a demented tennis ball....

Talking of bags of air, you might need to be aware that although the balloon may be lighter than air, the CAA regulations refer to mass. It’s more than possible that your balloon could stray into LMA territory, requiring build supervision, test flights and pilot certification. For example, the one you linked to with a 2500 cubic foot envelope would have a mass of more than 100 kg with fuel and equipment.

I have an annual eye test and always stress that I need to optimise my distance vision due to model flying - for which, along with longer drives, I usually wear single vision contact lenses and use reading glasses when close vision is required. So far, my optician (various branches of Vision Express, due to work relocations and retirement) has been responsive and efficient. The idea of formalised eye testing for driving doesn’t worry me but it does seem to be an additional complication which shouldn’t be necessary and would no doubt involve additional expense unless simple evidence such as a current optician’s prescription would suffice. Although I’m quite short sighted, I’m lucky that my visual acuity is better than average (think of it as screen resolution). A history of glaucoma in the family has meant that my eye testing has been free since I was 40 so I have little excuse - and every reason - to keep my vision monitored regularly. As such, it feels odd to me that others may not be having regular checks though, as eyesight is of such importance - especially to model flyers - and early diagnosis of impending problems can have significant impact on the success of any treatment. It would be interesting to know whether any of us visiting this thread doesn’t get their eyes checked reasonably regularly and their reasoning behind it.

No slowness but I’ve seen a couple of error 500 messages. I’ll alert the tech team.

You’re looking at a speed of around 240 mph in old money. While you may hear many claims of models exceeding 200 mph, few are capable of much above 120 mph so you’re in territory unfamiliar to most models. With the masses involved in the size of model capable of such speeds and loads - fuel alone will probably come in at 4 or 5kg, I suspect you’re going to struggle to stay under 25kg but then I suppose that’s what makes the project challenging! If there are any plans to develop the exercise to a flying prototype, you will need to pay careful attention to avoiding control surface flutter - at such speeds, it’s a serious danger to your airframe. It might be worth approaching the Large Model Association for advice and ideas. Their members and inspectors will have more experience of more serious structural design considerations.

I’ve got water slide transfers which I printed and applied in 2003 which were protected with polyurethane varnish (also necessary to clear the white backing). These have lasted perfectly despite the years of wear and tear on the model.

Old fashioned (in this country) term for a rechargeable battery dating back to the days before many homes had mains power. If you had a wireless receiver, you would take your glass cased accumulator to a local electrical shop, chemist etc. to have it charged. Many German products use the term "Akku" to mark power input ports, for example.

A pilot that I know spent multiple hours on a simulator every week. Beginner - no, he was an international level indoor aerobatic pilot and member of an outdoor show team. There are some very good simulators out there, perhaps more suited to flat field training than Picasim so perhaps ask around as someone might be able to lend/sell you theirs - but they all give you hand/eye coordination experience. It's not the same as real world - although the better ones allow reasonable simulation of weather effects and pilots who have learnt on simulators do spend a while learning to cope with the real world. However, in my experience, simulator training does mean they tend to progress faster. As others have said, small "toy" models don't teach you very much and can actually slow progress as they can introduce bad habits/practices.

As I'm far from JD8's farm, and the wind was westerly on both occasions, I think I can safely relate my experience from an impromtu competition hald at our gliding club back in the 80s. The material of choice for the envelope was the extremely thin plastic bags supplied by dry cleaners, assembled with Sellotaped seams. Several people used foil trays but I found that a simple thin wire frame across the opening with meths soaked cotton wool twisted on to it sufficed. Initial inflation was by fan heater on an extension lead, followed by lighting the burner shortly before launch. One element of the judging was for imaginative envelopes. My first attempt (for some unremembered reason the first date was called off but I decided to fly it anyway) was with "The Gossamer Special" - an 8 foot high, rather risque basically tubular shaped structure which disappeared over the horizon. (Australian readers of a certain age may find an additional irony in the choice of fastening product!) I was lucky enough to win the competition proper with a semi scale model of an amply endowed girlfriend of one of my fellow club members! Those were in the days before I became a serious moderator with a sense of humour amputation of course...

I always advise (and practice) sanding the flash off APC trailing edges. Even so, I've been caught out by the odd one on someone else's model that I've been involved with - and not necessarily while starting their engines! Rubber finger stalls (and Elastoplast!) were made for hand starting with APCs in particular - I've never been comfortable using chicken sticks.

Better not to speculate but there were some very lucky people in the Bombadier.

Well worth following the link!

Does denatured alcohol mean anything to you? "Denatured alcohol, also known as methylated spirits, metho, or meths in Australia, Ireland, New Zealand, South Africa, and the United Kingdom, and as denatured rectified spirit, is ethanol that has additives to make it poisonous, bad-tasting, foul-smelling, or nauseating to discourage its recreational consumption."

Sounds rubbery.

I think that once the novelty wears off, the limitations of flying in the same limited airspace mean that many of us don’t find much interest in FPV.