LF mast length

[grigorib]

But, regarding the mast length of the LF, I recall they wrote "1 m" when the first one came, which can be anything from 51 cm to 149 cm so being 95 cm is just fine and not "technically wrong"
PF

Sorry, NOT, how can 100 cm ever come close to being the same as "anything from 51 cm to 149 cm"?
1 meter equals 100 centimeters!
Specs are ment to be just that and it is indeed VERY "technically wrong", PERIOD!
Amazing how the world seems to be indifferent to "alternative facts"
R H

Well, technically as Horst also writes, a measurement of 1 m can be from 51 to 149 centimeters.

I dont think anyone will find that reasonable if talking about a mast/strut of course, eventhough correct

The first LF was spec'ed as a "1 m mast", and doing so, a 95 cm mast is very fair and reasonable I think most can agree

1 m does not equal 100 centimeters though, that is for sure

As when should you stop then ?
You could also say it equals 1000 millimeters ?
Or is 1 m 100.000 centimeters ?
Or is 1 m 1000000000 nanometers ?

No it is not, 1 m is 1 m and nothing else in terms of setting measurements up, no discussion

The decimals and units, to use them correctly and not abuse them (as most do, but okay when you dont know), are essential in terms of giving a correct value or measurement.

PF

I'm not sure by what means 1 m could be anything between 0.51 m and 1.49 m. Can you explain please?

LF has a picture on their page (I listed a link and the pic above) which states "1000mm" which is 1 m or 100 cm. In mechanical engineering you use millimeters (centimeters are rather civil engineering units) and that's what they properly used on the drawing. Having mast 35" long means not matching specs and qualifies for being a reject.
I'd send it back.

[Peter_Frank]

I'm not sure by what means 1 m could be anything between 0.51 m and 1.49 m. Can you explain please?

Sure I can.

The first LF specifications stated their mast was 1 m.

Later it seems they have made a different statement, 100 cm or 1000 mm ?

But if you only relate to 1 m, it is NOT the same as 100 cm or 1000 mm, as the latter only has a very small margin of tolerance.

A 1 m mast can (if ONLY talking technically about how numbers and measurements are defined) be between 51 and 149 cm and still be a "1 m" mast.
A 100 cm mast should be between 99.5 and 100.49 centimeters to be right.
A 1000 mm mast should be between 999.5 and 1000.49 mm to be right.

So my point is, referring to the original LF specs, that stating the mast is 1 m, then being 94 cm is quite good and close.

BUT, another issue is, how is the mast measured ?
Is it from bottom of board, to top of fuselage ?
To bottom of fuselage ?
To center of main wing ?
Or could it also be from TOP of board, to somewhere on the fuselage ?
Or ?

So not that easy to define what mast length is

I know, an odd thread, but since you started it tegirinenashi I would comment.

PF

[grigorib]

As they show in their drawing it's supposed to be 1000mm from bottom of connection plate attached to the top of the mast.
While it's ok to argue that you can round anywhere from 51cm to 149cm to approximate length of 1m but at this scale and expected precision, a 10% bracket (and that's just on shorter side) is not something that I'd call acceptable.
Some might argue that their supplier can manufacture 11 masts with 10 mast material and thats not far from stealing. Looking at the wind charts I'd rather blame it on incompetence.
They can go further supllying 51cm masts claiming it's 1m but we're in free market, I wanna see how that is going to fly

[tegirinenashi]

Remember, Nvidia GTX 970 ordeal? The claimed card capacity (=4Gb) felt short of actual 3.5 usable memory. This is not even like they soldered in only 3.5G instead of 4G; there were full 4GB memory chip set; it was simply that the card driver failed to use more than 3.5. The next thing, you know, vultures (oops, lawyers) were all over the case. Now imagine the defense strategy:
1. 4GB memory spec is not actually "4". It is anywhere between 2 and 8.
2. The 0.5 Gb was lost during conversion from Giga to 1000000000.
They would be laughed out of court.

[Kamikuza]

There's a rule of thumb for bolt depth which I can't remember exactly. It's either 1d or 1.5d of bolt thread diameter.

Roll with 1.5d just in case. So 6mm bolt = 9mm thread depth.

Yeah that's it.
http://www.gizmology.net/nutsbolts.htm
6 threads for 98% hold, 1.5-2d for strength in aluminum.

...so why are they using like, 60mm bolts? Are they structural as well? The Slingshot mast/plate bolts are shorter than the LF ones were, but the Zeeko setup with no collar uses 3 bolts...

Redundancy? 60mm of thread has a long way to unthread before the bolt falls out and the foil falls off.

A small amount of slack makes itself felt though. I though the collar had deformed, but when I had a closer look, the bolt was perhaps half a mm undone/compressed. I could feel the wobble when the head broke off the other one too, and they're all jammed up in there under the board.

We'll see. Too late to do anything before we leave.

[grigorib]

Dammit, if people order a pint and get 9 oz the place won't stay in business for long
What about ordering a box 1m x 1m x 1m and getting one 51cm x 83cm x 102cm. Would you still consider it to be ok?/

[revhed]

1 m does not equal 100 centimeters though, that is for sure

Wiki
centimeter (American spelling) is a unit of length in the metric system, equal to one hundredth of a metre,
https://en.wikipedia.org/wiki/Centimetr ... _of_length
https://en.wikipedia.org/wiki/Introduct ... tem#Length
http://mste.illinois.edu/dildine/tcd_fi ... length.htm
https://answers.yahoo.com/question/inde ... 627AAcDldB
http://www.metric-conversions.org/lengt ... meters.htm
http://www.webster-dictionary.net/definition/centimeter
I could go on and on.......
R H