Wikipedia:WikiProject Aircraft/Units talk

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Current (little) issues I have with the table:

Both the thrust/weight and the power/mass columns are pretty much useless for aircraft with both propellers and jets. So I'm omitting them on any such aircraft.

I think rate of climb in metric should be metres per second, which is a standard.

Why does 'length' have 'ft in' but all the other imperial dimensions are ' "?

Is the 'beta table' above grey because someone wants to change the color AGAIN or just to show it as different than the other one?

Lastly: regardless of all these, let's make this table a fixed standard soon so that we can put one of these up on every aircraft article and not have to go back and change it! —Morven 18:24, 2 Mar 2004 (UTC)

The short abbreviations are not genearlly used in the first of a list. Usually the ft and in are at the top then the ' and ' ' used after in formal listings.

The color was just to make the table all the same color rather then mix of gray and blue. Whether its this color are blue doesn't matter, though I made the gray close to the color that rings many photo's with the idea of a standard color.

This was my idea of a final table. The idea was to modify this one till were all reasonbly happy with it as the final refinement place. Alternatively, perhaps others can make there 'ideal' table and we'll mesh them together. It was an attempt to move away from constant changes to the main standard table.Greyengine5 19:35, 2 Mar 2004 (UTC)

Agree with the comment about Thrust/Weight, Power/Mass (but then again, I'd be just as happy to see these go altogether.)

m/s would indeed be the proper SI unit for climb rate, but in practice this is always quoted in references as m/min (just as speeds are quoted in km/h, which isn't "proper" SI either). Common usage should prevail. --Rlandmann 22:23, 7 Mar 2004 (UTC)

Which other lists use "ft" and "in" at first and then change to ' and " later on? I don't like this feature, but will use it if this is indeed common usage. --Rlandmann 22:23, 7 Mar 2004 (UTC)

I don't think any do. Personally, I'm altering all the tables I put in so that it's ' " every time. If you understand Imperial measurements, you understand that notation. If you don't, you'll be reading the metric version anyway ...

I'd also be happy standardising on 'ft in' if people prefer that. —Morven 00:37, 8 Mar 2004 (UTC)

I agree we should keep it with the more compact ' and ", for the reasons that you've already spelled out. Since both of us are apparently making the same alteration (and at the moment are the two people actually using the table most heavily) I'll change the template to reflect that... --Rlandmann 01:26, 8 Mar 2004 (UTC)

The ' and ' ' abbreviations can be used for other things, namely for units of time and for minutes and seconds of latitude or longitude. Despite the obvious ability to use context (as is usually the case anyway)- its really nonstandard usage to not leave it. There are uses of it without explation but most formal resources I'v come across (at least in books anyway) do not, and for encylopedia where many people who might not know these abbrev. its probably more important.

I'll revert it and then you to as primary users of table can make the final decsion. I think using ft and in for the whole list would be better then just using the shortened abreviations. If ' and ' ' are much preferred then I wont change it back a second time as there's some leeway with such a short list anyway. Another alternative would just be to use decimal feet and avoid inches like in the table above. Once again there's some leeway with usage- though I did have points taken off once for not using ft and in at the top of list in a lab once- with this "list" only have 3 rows its probably not so important though. Greyengine5 18:54, 8 Mar 2004 (UTC)~

Symbols (abbreviations) for feet and inches

Like Greyengine5 I would like the template to use ft' rather than ''.

I had not looked at this discussion page till now. I noticed the inconsistencies and had adopted a ft as my standard symbol. I was occastionally making changes to that effect. I did not realise that this was on the template - sorry.

My reasoning was something like:
when feet are combined with other units we see ft/min rather than ''/min.
Secondly, symbols like '' are used to mean other units like minutes of time and minutes of angle, whereas ft is less ambigous.
Thirdly, the metric and non-metric communities are not mutually exclusive, and they do read each others units, particularly in this domain of aviation where the foot is widely used.
Fourthly, I believe that ft is the symbol used by aviators.
I think
Ceiling: 15,000 ft
is much better than
Ceiling: 15,000 '

Trying to use plurals in symbols

I had a discussion with Morven and Rmhermen about plurals in symbols. Here are selected quotes:

If an abbreviation for a unit is used, then arguably the abbreviation should not be pluralised; this is definitely the case in metric (we never say '300 kgs' because of the confusion with 's' for 'seconds'). However, it is common and not incorrect to use 'lbs' as an abbreviation for quantities of multiple pounds. —Morven 20:43, 9 Mar 2004 (UTC)

Response from 62.49.16.208
... with abbreviations (or symbols) as you say, the plural 's' can be mistaken for seconds in and is therefore banned from metric units in symbol form. Although there is no authority that can or has imposed such a ban for non-metric abbreviations, the same logic is reasonable and consistent. Thanks for your feedback.

... that's a version I can live with, since I don't care either way about whether it's 'lb' or 'lbs'. Neither is per se wrong, but if you wish to standardise on the former that's fine with me! —Morven 21:51, 9 Mar 2004 (UTC)

It is not fine with me. Please stop changing lbs. to lb. It may be metric usage but it is not standard English system usage. It is not going to be confused with lb/s (notice the slash and lack of period). Even the U.S. military which uses Metric lists it as lbs. Rmhermen 14:32, Mar 10, 2004 (UTC)

Response from 62.49.16.208

No, it is definitely not 'standard' to pluralise abbreviations of English units(if 'standard' means the vast majority). Try a survey. Wikipedia reports
153 hits for 'lbs' and 216 for 'lb',
11 for 'gals' and 91 for 'gal',
1 for 'length ft ins' and
238 for 'length ft in'.
Far from being a 'standard', it may even be the minority style. Interesting debate though, I had never even thought about it till now.

Please can we be consistent with plurals? Can we standardise on 'lb and in?
Bobblewik 20:25, 23 Mar 2004 (UTC)

Experiments with Google seem to show that "lbs" is more common usage than "lb" on the web. Phrase "100 lb" returns 128,000 hits [1], while "100 lbs" gets 228,000 [2]. "200 lb" gets 73,700 [3] while "200 lbs" gets 160,000 [4]. I've tried this with a variety of weights and the "lbs" version typically gets between 1.5 and 2 times the number of hits that "lb" does. So unless anyone can point to a reputable UK or US usage guide that privileges "lb" over "lbs" then I say we stay with common usage.

I prefer ' and " over ft and in, only because it seems neater and more compact. Are you seriously suggesting that in a row marked "length" anyone is going to think that it's referring to minutes and seconds (angular or time)? However, I take Greyengine5's point that the spelled out versions do seem more common (though only just) in tables in print references.

Interestingly, Google experiments seem to suggest that "in" is more common than "ins" (the reverse of lb/lbs), but there's a problem because the results don't distinguish between "in" as an abbreviation and "in" as a word, so my confidence in that result is fairly low...

Personally, I don't care too much one way or the other, but before we decide to change the template again, I'd like to hear from other people who actually use the table. --Rlandmann 01:51, 28 Mar 2004 (UTC)

I mentioned this before, but, what about using decimal feet as a compromise. There's an example of this use on a table in the archived debate. As for lb/lbs in/ins I put my vote in for the shorter ones

• I think I prefer ft and in- space doesn't seem to be much of a issue such as here Junkers Ju 290, and the ' can be hard to see on higher resolution monitors. Combined with the fact a great many people dont know of the ' abrev. i think its worth using it spelled out, or at the very least use them at the tops (Perhaps there's somone with english degree on wikipedia who can clarify what the formal usage is for unit abreviations)

.Greyengine5 19:21, 28 Mar 2004 (UTC)

---

I think the problem is that people are applying plain speech conventions to unit symbols. A google search for the phrase "a 100 lb" gives 6,680 results whereas a search for "a 100 lbs" produces only 755. It is never wrong to use the abbreviation lb but it is sometimes wrong to use lbs.

I could not find any source that says do not use lbs for plurals but nor could I find any source that says do not use lb for plurals. My vote is still for one abbreviation for both singular and plural. That would be consistent with what we do for other non-metric units (e.g. in) and consistent with metric.

The NIST is the US Federal organisation for weights and measures. It gives definitions of American units and provides abbreviations at http://ts.nist.gov/ts/htdocs/230/235/appxc/appxc.htm It lists ft' and in but not '' or "

There is also the "Uniform Packing and Labeling Regulations" which is a template regulation adopted by many US state legislatures.
http://ts.nist.gov/ts/htdocs/230/235/h130-04/PDF/07_IV_PackLabReg04.pdf
It says "Any of the following symbols and abbreviations, and none other, shall be employed in the quantity statement on a package of commodity:" and then goes on to list <ft> and <in> but not '' or "'.
If you search the document for lb, you will find that they use it to mean both singular and plural.

The Canadian Institute for National Measurement Standards uses lb to mean both singular and plural. http://inms-ienm.nrc-cnrc.gc.ca/faq_mech_e.html

This British law gives the abbreviations permitted for trade: http://www.hmso.gov.uk/si/si1987/Uksi_19871538_en_6.htm It mentions ft' and in but not '' or ". Although we all know that the abbreviation exists.

One minor technicality.... the google calculator recognises ft in but does not recognise ' ". Thus it is easier to convert 5 ft 10 in by simple cutting it from wikipedia and pasting it into the google search field. It is harder with 5 ' 10 " and actually it is easier to edit the wikipedia entry first to 5 ft 10 in and then cut, paste and convert.

Many of us work in software. I can imagine a field giving mass with the text label lb' to the right of the field. It would be a weird requirement to check whether the non-metric value is plural and then rewrite the label with an s e.g. as lbs. I can't imagine using '' and " instead of ft and in on a software product. Only tangentially relevant to this debate though. Bobblewik 03:03, 29 Mar 2004 (UTC)

Thanks for that - with all that in mind, you and Greyengine5 showing a marked preference for this, and Morven and I having stated positions of not caring terribly much either way, I suppose we should go ahead and make the change. --Rlandmann 06:28, 29 Mar 2004 (UTC)

I have noticed a some minor points when using the table. Firstly, Power/mass ratio is probably better in W/kg rather than kW/kg. A value of 160 W/kg looks better than 0.16 kW/kg and it fits with my 'rule of 1000' guideline i.e. try to have numbers in the range 1 to 999 (I extend the range sometimes by one more digit to the left and one more to the right).

Secondly, we have focussed on military aircraft. Civil aircraft do not have a combat range, or armament. They often have passengers and a cruise speed. Of course, I can make adjustments as necessary when using the table, but I wondered if you guys had any thoughts on the standard table. Bobblewik 13:15, 1 Apr 2004 (UTC)

I think that there was general consensus some time ago that when the current table stabilised there would be real value in creating templates out of it for broad groups of aircraft that share characteristics. At the time, sailplanes and helicopters were the groups suggested. The main table already contains "capacity" for airliner seating or cargo load, but specific civil fixed wing and civil helicopter templates could be done too. Any other suggestions?

Most, if not all, military aircraft also have cruise speeds available, so if you wanted to implement this, it could be done across-the-board. My personal feeling, however, is that the table's already too bloated, although I know that view's not unanimously held.... (airfoil sections anyone?) --Rlandmann 03:01, 2 Apr 2004 (UTC)

I agree that the range of figures returned by kW/kg is quite ugly and somehow counter-intuitive. 160 "looks" like a real number to me, while 0.16 does not... Nevertheless, these seem to be the units that this ratio is most commonly expressed in (no doubt because they're the units that the powerplant and mass are commonly given in - inexcusable laziness when dealing with SI, but there it is...) Again, I think we must bow to common usage. --Rlandmann 04:14, 2 Apr 2004 (UTC)

Common usage is a useful measure but it is not always a guide to what should really be done. After all, people often write lb/hp/h (pounds per horsepower per hour) when it should be 'pounds per horsepower-hour' (or even 'pounds-force per horsepower-hour'). However usage is relevant to the debate so I decided to do the google test:
1,510 for W/kg specific-power
333 for kW/kg specific-power
462 for W/kg aircraft engine
141 for kW/kg aircraft engine
199 for W/kg jet engine
118 for kW/kg jet engine
144 for W/kg specific-power aircraft
52 for kW/kg specific-power aircraft
111 results for W/kg aircraft .mil
32 results for kW/kg aircraft .mil
29 for W/kg jet-engine
12 for kW/kg jet-engine
So prefix options are being used by others. In fact, I would be happy if we left it up to the individual page editor. As long as the units are correct (e.g. newtons for thrust rather than kg), then prefixes don't particularly matter. I have been using g and kg, N, kN and MN, m and km according to what I think is best in context (often when numbers have 3 or 4 places to the left of the decimal or 2 or 3 to the right), just as I would in the rest of my writing. Authors and readers should not be mystified by these prefixes. But it doesn't bother me much either way. I am merely letting you into some of my minor thoughts.
Bobblewik 11:33, 3 Apr 2004 (UTC)