Massive problems pasting links into this. Instead, open the pdf at http://naca.larc.nasa.gov/search.jsp?R=19930093644&qs=N%3D4294927712%2B… or if it’s easier Google “The selection of propellers for high thrust at low airspeed”.. should be the first result.

This NACA report, gives the hydro/bracket equivalents I mentioned above, table II of the document. Also note ‘Activity Factors’, a nice shorthand, mathematically-derived guide to profile. The higher the AF, the more ‘paddly’ the blade. The table shows this increasing as the blade is ‘cropped’

In that vein, also then Google “working charts for the calculation of propeller thrust” – table 23 shows some equivalent profiles.

I checked, and the pitch change drive mechanism at the root of a hydro blade is quite different to that for a bracket type.. it would be a tough job to swap them out.

Little bits I have picked up.. prop de-icing was fitted, certainly to the DH Hamilton-based bracket props on the Whirlwind. It is indeed oddly passed over in many AP’s etc, but in the case of the WW there is a diagram and brief description. The pipes and slinger ring were a simple modular option, and could be fitted to any DH/Hamilton prop. There was more than one design, Hamilton’s own, and one by Dunlop (IIRC).

Going back to commonalities of numbers, DH had a very definite logic to their system, at least initially. The first 5 or 45 meant metal bracket-type and metal Hydromatic respectively. The next was series, relating to shank size (equating to the ‘thousand’ series number of the assembly), and the next was a drawing number. Again IIRC the next is direction of rotation, 0 for right-hand, 5 for left. The last digit is the length removed from design diameter.

I can’t divine any equivalent pattern to the Hamilton system for blades. One thing, though, 6 didn’t mean paddle. The very needle-like Hamilton 6101 is a case in point. Incidentally this might be the same as the DH 54xxx blade on the Blenhiem (I have it written down somewhere what it is) but without the excellent idea of 3d scanning there is, ludicrously, no way of knowing.

I guess I meant with a consumable item like a pint of milk, when it is consumed, it is gone. Not sure it’s an important distinction!

No, that’s not magical. That is indeed retail.

You buy a pint of milk. You do nothing, no transport, storage, refrigeration, advertising, interest repayments (ahem) or anything. You then sell the pint of milk for z more than you bought it for. You add no value to it, but because someone else thinks they can perform the very same trick with that very same pint of milk they will pay you z more than you paid.

Ok, not magic – but nice ‘work’. NOT KNOCKING IT. No politics of jealousy. But what a system.. and not really analogous to retail. There is no ‘consumer’ at the end of the chain, just a chain.

Nothing, I guess. I suppose its all to do with perceived value, but rather than there being an intrinsic value in the widgets themselves it’s the mutually agreed value of the company that makes them that adds to wealth when it goes up. Or the company that cleans the offices of the company that makes them, or the company that provides the phones for the company that cleans the carpets of the company that makes them, or whatever. Whatever the shares are in, I can’t argue with anyone buying for x and selling at x+y. At worst it’s surely harmless. At best it might even be wealth creation, though I’m not sure. It makes my head hurt to follow the real value when it comes to share dealing (as opposed to virtual, ascribed value – the ‘share price’). As a caveat there are some activities that really should not be managed in the interests of shareholders rather than customers. But I’m sure people guessed that already, I’ll spare everyone.

EDIT – thinking about it, I guess if person A is gaining x+y by selling then the person B buying is parting with x+y at the same time, and the overall wealth in circulation is unchanged. The next time that share is traded, assuming its price has risen by z, the exchange is for x+y+z, but the actual total wealth actually in circulation still remains the same (person B picks up x+y+z, but person C PARTS WITH x+y+z at the same time, net sum zero. The only real increase is in the perceived value of the item, the share. And person B makes a profit of z. All a bit magical, really. Bit like house prices.

Oh cr*p. What are we going to argue about now? :very_drunk:

I mean it constructively, CD – read what I wrote again, please.. I know you’re not a knee-jerk like some on here, so it will be worth checking what I have said before arguing against something I didn’t say..

Lending money is not illegitimate profit making, in my opinion, and I thought I had made my thoughts on that plain.

There is nothing wrong with service industry.

I do not hate banks. As for understanding finance – there are plenty of people working in finance who will admit to not fully understanding finance any more, but that’s another issue. As I keep insisting, I do not think that banks are bad or their profits immoral. To say I do is putting words into my mouth to then argue with.

I already am used to banks and use them every day, personally and professionally. My only contention was a fairly pedantic point about raw productivity, which is NOT THE SAME AS SOCIAL WORTH, and does not detract from their necessity in a modern society.

Yes to most of that, the bank has taken the calculated risk and it is right it should be rewarded for doing so, etc. The function of the bank, and the legitimacy of it’s actions are clear.

The bank has contributed to the generation of the added value, as did the metalwork teacher who first introduced Bill to widgets, as did the designer of the widet-o-matic, the fireman who saved the factory when the widget-o-matic exploded, the nurse who removed the singed widget from Bill’s left nostril allowing him to return to work, the burglar alarm installer, the lawyer, the plumber..

But it was still the widget manufacturer who added the value. The others (except possibly the Acme Widget-o-Matic Co.) are service industries, servicing the wealth-creator, not wealth-creating themselves. Legitimately profit-making from the production of widgets, but not the same thing.

The two are not entirely symbiotic. I doubt the first hunter to chip away at a flint to make it stabbier went to a bank first, or even when he (or she) offered to make more ‘stabby-flints’ for his (or her) neighbours in exchange for meat and furs..