Here is a list of all the postings John Bunting has made in our forums. Click on a thread name to jump to the thread.
|Thread: Tribute to the DH Mosquito|
I still have a 1/72 solid scale model of the Mosquito, which I made in 1943 when I was 13, not long after it came into service. This programme inspired me to repair it, as a few bits came off years ago. The U/C does actually retract, but I'll have to make some new doors for it, as they are missing.
Another thing they didn't mention in the programme was that the Mosquito was partly derived from the DH Comet racer of about 1935.
|Thread: 'Flight' archives on-line|
Ah well; memo to self; RTFM.
Anyway, I thought most of you guys knew the Flight archive already!
They have a request for anyone with stuff that's missing, e.g. pre-1909 issues, to get in touch with them. I see Tony B has issues back to 1905. Anyone know which year they started?
The ‘Flight’ archives, going back to 1909, are worth browsing for general interest or unusual types for scale modelling etc.They had a regular model page in the early days, and I was surprised to find a model using sheet and strip balsa published in May 1921. I always though balsa didn’t come into use in the UK until about 1930.
Ever heard of an aircraft called the Jacuzzi? No kidding; it was a seven-seat monoplane made by Jacuzzi Bros., of Berkeley, California. See ‘Flight’, March 3rd 1921, p. 147. Whether they were also the makers of the other Jacuzzi, it didn’t say.
|Thread: What is happening with my Lipo?|
|If, as Steve suggests, the circuit resistance has changed in some way, how about the ESC? It might have been interesting to monitor the full-throttle load voltage at the motor terminals, as well as at the battery itself.|
Hi Erfolg; I've only just now seen this.
I wonder if the internal resistance of the cells has gone up. That can happen with NiCad and NiMH cells, as they get older: I'm not sure about LiPos. For a 3s pack, the current would be only about 3 amps at your wattmeter reading of 28 to 34 watts. Did you check the cell voltages while on load?
|Thread: What Goes Up|
|Thanks, Tom and David, for your kind offers of help with FoilSim. No trouble finding and downloading it, but I'm new to zip files and I expect I'm doing something wrong in trying to unzip it. I'll consult a fellow club member, who will probably spot it immediately!|
|Has anyone here downloaded the NASA 'FoilSim' program that David mentioned in the May issue? I tried, but am new to Zip files, and must have done something silly, as I didn't get the necessary interactive part.|
|Thread: Hawker Hind Posts?|
The Shuttleworth Collection has a Hind. Also see www.hawkerhind.co.uk, mainly about the Hinds recovered from Afghanistan some years ago.
|Thread: What Goes Up|
Just reading Part 4, which arrived this morning, and am intrigued by the references to 'vortex shredding', in the photo captions. Now there's an idea: shred the vortices, and maybe you'll get the drag down a bit!
If you ever do the flat plate tests, David, I wonder if you'll get similar results to F W Schmitz. I think he got a funny boomerang-shaped lift curve, with a sudden decrease of slope at about α=5°, Cl=0.5.
Thanks, David: all most interesting. I hardly imagined that my guesswork would turn out to be so closely investigated in your experiments! Can you also tell us the chord and thickness of the test airfoil, and the tunnel flow speed(s)?
It occurs to me that if the facilities are still available, one further case might be examined: a flat plate airfoil, which should be cheap to make.
Having asked about the lift of symmetrical airfoils, after Part 1, I've been looking forward to your comments on it in Part 3.
The nub of the matter seems to lie in your words, "this wing wil 'flip' from significant down-force to significant lift as we pass through the zero singularity that it never manages to actually occupy!".
This leads one to wonder just what the lift curve actually looks like, for these very small angles of attack. It seems to suggest that the slope of the curve may be larger there than it is for larger angles; or else that there may be a small hysteresis loop around zero, so the wing goes very slightly beyond the theoretical zero lift angle, before the up or down force 'flips' from one state to the other. I wonder if any wind-tunnel tests, or even mathematical modelling, show any such behaviour.
Talking of maths in general, I read the 'Aeromodeller' from 1945 onwards, and the amount of maths then was frightening, compared to today. Most of it, unfortunately, based on full-size data, at much higher Reynolds numbers than for model flight. I remember covering sheets of paper with figures, to work out the angle of incidence for maximum L/D or power factor. But the one that really sticks in my mind was a series of articles, stuffed with equations, entitled "Counteracting the effects of engine failure in twin-engined model aircraft". Happy days!
|Thread: how to hide new planes from wife, advice please|
In an odd way, I'm in a fortunate position here, as my wife's main hobby - keeping a horse for riding - costs more than my aeromodelling. So, keep an eye open for any non-essential expenditure of hers which is equal to or greater than your modelling costs.
But of course the key word here is 'non-essential'. Her ideas about that may not be the same as yours.
|Thread: moving house|
My model storage solution, for what it's worth, when I had the house enlarged a bit, was to buy a pack of large pressed steel shelf brackets - cheap from Screwfix - and mount them on two verticals against the wall, suitably spaced. No shelves; just put your fuselages, wings etc. across the brackets. Stick strips of foam or cork on them, to discourage models from sliding off. For my typical model size, I got seven levels, from near-floor to ceiling.
|Thread: What Goes Up|
David, I think these ideas are sometimes a bit counter-intuitive. I remember - when I was much younger - being surprised by Bernoulli's idea, because I felt instinctively that if air flowed through a constriction in a pipe, it would be compressed, so the pressure would increase. Also, if you swung a piece of cardboard round at arms length, with its front edge tilted up a bit, you felt it lifting - obviously, I thought, due to the pressure on the underside! But the pressure distribution in airfoil test results usually shows that the decrease of pressure over the top surface is considerably larger than the increase on the bottom; (is this also true for a flat plate airfoil?). And when you hold a convex surface against water coming from a tap: it gets drawn towards the stream, although there is no flow at all on its other side.
Could you please comment further on your bit in the article about symmetrical airfoils? You say, "when aligned with the oncoming airstream the air travels the same distance above and below yet we know they generate lift in this condition, but how?" If by "aligned with the oncoming airstream" you mean that the datum or centre line of the wing is at 0 degrees angle of attack to the airflow - although it might be rigged at some positive angle of incidence relative to the datum of the whole aircraft - then I don't see how it can give any lift. Surely for a truly symmetrical section, zero lift occurs at zero angle of attack.
As a possible point of interest - as this thread has come to life again - I found that my PicooZ ran smoothly at full speed, but went into a state of noisy oscillation with a sudden decrease of rotor speed when I throttled back, so it dropped to the floor very quickly. I tried lubricating the gears and bearing, and finally fitted an extra bearing round the shaft where it comes out of the fuselage, but there was very little improvement. Anyone else had this problem?
|Thread: Identify this A/C please|
Was it built from a kit, a plan - APS perhaps - or maybe it was an American design, as you had a McCoy engine?
|Thread: Subscription freebee "RC Plane Master" simulator.|
One shouldn't look a gift horse in the mouth, they say, but not being very interested in flying egg-beaters, I must admit I was a bit disappointed when my RCM&E subscription gift turned out to be a 'Helimaster', i.e. a helicopters only system. If anyone is in the opposite position, with an unwanted fixed-wing system, and not too far from Godalming, Surrey, maybe we could do a swap.
|Thread: contact email address|
If I click on the rcme subscriptions address on the contact page it just enters ''rcm'' in my address box, not the full address. The other one, the ''MyHobbyStore'' subs address, works OK. Anyone else found this?
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