Piers Bowlan
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Posts posted by Piers Bowlan
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To add a further note on building wings, I mark the rib positions on the LE And TE stock. I then make a small indentation maybe 2mm deep so the TE & LE of the ribs fit snugly into the stock to increase glueing area. It is surprising how much stronger the joint is than just butt jointing and you end up with perfectly spaced ribs 😊. (A couple of old blunt hacksaw bladed taped together make a nifty tool for cutting small slots) If I am cutting my own ribs, I normally make them a little longer to start with but if they are from a laser cut set I don’t lose sleep if the chord is reduced by a few mm!
Just my 2p worth!
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I think modellers have been making wings straight and true for decades using just a perfectly flat building board with balsa parts pinned to it. Either plasterboard (my local B & Q sells ready cut pieces) or self adhesive cork squares available from eBay, work well.
An alternative to pins is to use a magnetic building board. Some people swear by them and I have seen them for sale at some of the model shows in the past. Thinks 🤔:- must try one sometime.
If the wing has washout just place a strip of balsa along the TE at an angle, such that the root rib is flat on the board while the tip rib is raised by the strip. If you are worried about glueing the ribs to the strip, cover it with some shiny sticky tape.
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1 hour ago, Andy Stephenson said:
1200 Wh/kg is impressive for a rechargeable battery but they don't state the power density i.e. the C rate which is the determining factor for the hobby.
By comparison methanol is 6400 Wh/kg.
Yes, unfortunately high impedance between the cathode and anode is another issue with this technology, which they are working on…
If they had solved all the problems we would likely be using them now but they have the potential to be a game changer.
A little light reading 😉
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On 03/07/2023 at 12:54, John Lee said:
I went to a talk at the Royal Aeronautical Society a few years ago given by the head of Airbus's electric flight research section.
If I recall correctly he said that their opinion is that whilst the will be incremental gains in battery efficiency, they could not see any prospect of a fundamental breakthrough. The reason behind this is that Lithium is number 3 in the Periodic Table (after Hydrogen & Helium) and its top left hand position position means that it has the highest useable negative electrochemical potential of any element, which is what drives battery efficiency.
I don't have the knowledge to challenge or prove this assertion, but it does make some sort of sense.
Yer cannot change the Laws of Physics (or chemistry), Jim!
I wonder how often has an eminently qualified and respected expert said something along these lines, ‘…could not see any prospect of a fundamental breakthrough because… ‘ There follows a reasoned explanation why. But, unforeseen discoveries prove them wrong again and again, (eg. Jet engine, transistor/IC, LCD screens, computers, The Internet!).
Solid state batteries have for some time offered the elusive prospect of a step change in efficiency and charge density. Cycle life has hitherto been a major drawback but perhaps no more?
They are also supposed to be safer and if aluminium is used instead of lithium, a lot cheaper, potentially. -
I am pleased Balsa Cabin are now selling the Wild Thing. Everyone should have one that has access to a half decent slope, whether beginner or expert. It is indestructable and will last forever, if not longer!
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Beautifully smooth flying, very realistic 👍
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10 hours ago, Cuban8 said:
Not a fair comparison. I wasn't thinking about the 500 hp motor or snazzy aerodynamics, but as usual, the hopeless energy density of the batteries and poor duration. They conveniently ignore all that. Yes, fantastic performance for a short time I agree, but from a back of a fag packet calculation and good old Google, their heavy batteries are the equivalent of a tiny petrol tank containing only a few litres of the good stuff. Not exactly going to get you across continents or even comfortably between airfields for those expensive cups of coffee. If that's not a blind alley, then what is?
There are some large scale experimental projects out there with serious money behind them. For instance there is a Dash 8 regional airliner flying with one of its two engines replaced by an electric motor powered by a hydrogen fuel cell. Light aircraft trainers are emerging with electric motor options. Pipistral Velis Electro and Diamond Aircraft for example.
There are several lines of research under way using different battery technologies. Metal/Air, solid state to name but two. Some may come up against an insurmountable problem (blind alley) only to reemerge when some bright spark (sorry!) comes up with a work arround some time later. Developing a new battery is not just about charge density but cycle life, internal resistance, safety and cost are other considerations. The reason why so much money is available for research is the prize if successful is very great. -
I expect you know Nigel but SLEC sell quality wing bands of all sizes.
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9 hours ago, Ron Gray said:
Great meeting up with everyone today, just a shame it was so blasted cold!
Do you have any photos of the event to share Ron?
I was tempted to make the pilgrimage but I had a great day sailing in Poole harbour instead. Closer to home too.Hopefully make the Modelair Scale weekend on the 22/23 July.
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Other commitments (Life) have scuppered any chance of making a start Andy but there is two weeks to go, which is a lot more than the PSSA 48h challenge!
House sale? Still negotiating!
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Building an ARTF? Yes, done a few of those. Bits that don’t always fit, occasionally structurally inadequate and supplied fittings that don’t cut the mustard, on occasion. Also, searching the internet to establish where the c of g should REALLY be! I have loved them all, even the turkeys as they provide their own challenges, which is what ‘building’ is all about. 😊
What I really want to know is what people mean by ‘scratch building’?
a) ‘I built it from a kit’.
b) ‘I built it from a plan’.
c) ‘I designed it myself’.
I consider c) as ‘scratch building’ whilst many think b) or even a) appropriate.🤔
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Thanks for the reply Chris. I was thinking of an E205 section myself. Construction would be balsa and brown paper covered EPS. I built a Blackburn Firebrand like this and it went together very quickly.
Whether I go ahead with the plan depends on whether my house sale goes through. If not, I might as well build myself a Dambusters Lanc!
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I have just found my old Tony Nijhuis Avto Lancaster (beautifully drawn) plan.
it looks like a semi-symmetrical but quite thick wing section. Would a thinner section work better for a glider version to improve penetration (less drag)? Alternatively just add more ballast!? Any thoughts anyone?-
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I hope to be there, I will look out for the hat Ron! Which models are you planning on taking?
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10 hours ago, Alan Gorham_ said:
What throws did you end up with Alan. I don’t have any instructions.Nice scheme by the way 👍
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When I first really got into aeromodelling back in the 1970s models were generally smaller and people had fewer of them. RC was expensive and unreliable. The Super 60, for example, was a ‘large model’ as I recall. Models and their engines and now motors, have grown bigger and ever more powerful with the advent of reliable multi-model memory radios.🤑
Perhaps smaller simpler models will predominate in future as modellers tighten their belts, and have just as much fun to boot. 😃
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Fortunately I have a substantial kit mountain in my loft and a pile of virgin balsa too. (Eat your hearts out!) For those not so blessed, depron sheet and hot-wire cut polystyrene are a cheap and often quick alternative to traditional modelling. It might not suit everyone but it has its advantages besides cost. For instance light models fly better and their their relative short life means you will build more models! 😁
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Are you sure it is the ‘prop adaptor’ that is bent? It looks like a substantial chunk of aluminium.
Is this the Motor fitted to your Tundra:-
If you remove the prop and run the motor does the end of the motor shaft wobble? Is there still vibration with the spinner removed? Have you tried balancing the prop?The motor may have partially come adrift from the model or you may need a new motor. In any event further investigation could be a good idea. 👍
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Editing posts test! Yep OK
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Correction… 3 showing in stock at Hyperflight… hmm 🤔
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Very nice looking glider Mike, a useful size too. The carbon reinforcement is visible to the fuselage wing seat and cockpit opening area. I hope the nose area is comprehensively reinforced too. I have an ancient Kyosho Stratos with a very lightweight GRP fuz which I reinforced with carbon tows but the nose cracked in an arrival. You can’t have too much reinforcement in this vulnerable area in my view.
Shame the Slash is showing out of stock.
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No problem on both macs (desktop and laptop) iPad and iPhone. Safari and Firefox, no issues with the forum.
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5 minutes ago, leccyflyer said:
The BAE 146 is a rare and highly sought after model which would command a very good price if put up for sale on eBay, BMFA classified or one of the FB selling sites.
BMFA have had a couple of well publicised auctions recently with hundreds of engines and kits sold. Might be worth considering if you plan to part with your HS 146 or anything else for that matter, when the next one comes up. If you join the BMFA you will get all the info on forthcoming events like the auctions as well registering to get your operator ID.
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Pete I’m sorry to hear of your awful fire scuppering your plans for a new X- fire kit. Did you read Outrunners post above saying that he had an old plan, perhaps you could PM him to see if you could obtain a scanned copy. Failing that maybe you could ‘reverse engineer’ one if you got hold of an old x-fire airframe. After all it’s been done with full sized aircraft!
I rather fancy a X-Fire kit myself.
Looking for a wing jig
in Gadgets and Electronics
Posted
Personally I cannot see what a wing jig will provide that a flat building board won’t. On the other hand the Great Planes type jig requires the holes in the ribs to be cut with laser accuracy as kc pointed out. The steel or carbon fibre rods are the ‘datum’. A datum is provided by a flat building board. There might be case for a wing jig with a semi or a fully symmetrical wing section but I have built those before on a flat building board too, either using rib-tabs or by shimming the LE & TE with care. So not really a problem.
So rather than spending money on a wing jig I would buy more balsa, but that is just me! 😁😁😁