motorgliders as towplanes

[Bob Kuykendall]

On Mar 20, 8:17*pm, Uncle Fuzzy > wrote:
> ...My favorite example was an exhaust stud on a 1998 Olds
> Intrigue. *Engine side - SAE exhaust flange side - metric.

SAE and metric threads on the same stud? Yup, that's odd all right.

My favorite example of transitional hardware is the Volvo 240 series.
You'd find SAE hardware on anything it inherited from the 140 series
(most bodywork, a lot of the driveline) and metric on anything
introduced new with the 240 (B21 or later engine, M41 or M46
transmission, MacPhereson strut front suspension).

Thanks, Bob K.

[Martin Gregorie[_4_]]

On Fri, 20 Mar 2009 14:30:04 +0000, Jim Beckman wrote:

> But it *does* make it the right answer to the written test when that
> test is given by that same authority. For the test, concentrate not on
> what is necessarily true, but on what the FAA wants for an answer.
> After the written is out of the way, just learn to fly the aircraft.
>
Yes, and I learnt it as the answer to that Bronze question. It just
annoys me that official publications should enshrine myths as some sort
of truth.

Its no better than introductory texts showing packets of air dividing at
the LE of a ring and meeting up again at the TE, when a photo taken in a
wind tunnel shows clearly that doesn't happen. Far better to publish the
photo than a bogus diagram.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[The Real Doctor]

On 21 Mar, 13:30, Jim Beckman > wrote:

>*Are there any British
> gliders left that are old enough to have used Whitworth hardware?

The UK car industry switched over to UNF/UNC in the early sixties, but
I wouldn'r be suprised to find Whitworth/BSF in anything Slingsby made
until the late 60's. They were masters of improvisation ... for many
years Slingsby glider main wheels were surplus Spitfire tailwheels.

I have to keep a full set of imperial tools for my Herald and a full
set of metric ones for my DS. I still have a Whitworth set from when I
had a 1959 Morris Minor but it doesn;t get much use. The Micra just
never needs mending, so nut sizes are irrelevant ...

Ian

[The Real Doctor]

On 21 Mar, 15:19, Bob Kuykendall > wrote:
> On Mar 20, 8:17*pm, Uncle Fuzzy > wrote:
>
> > ...My favorite example was an exhaust stud on a 1998 Olds
> > Intrigue. *Engine side - SAE exhaust flange side - metric.
>
> SAE and metric threads on the same stud? Yup, that's odd all right.

My friendly local tool shop used to sell UNF/UNC nuts and bolts ...
with metric heads. Confused the hell out of me when I had to replace
some of them years later.

Ian

[The Real Doctor]

On 21 Mar, 16:48, Martin Gregorie >
wrote

> Its no better than introductory texts showing packets of air dividing at
> the LE of a ring and meeting up again at the TE, when a photo taken in a
> wind tunnel shows clearly that doesn't happen. Far better to publish the
> photo than a bogus diagram.

Oh, that one drives me mad. Not only does it not happen ... there is
no conceivable reason why it should happen. And yet many many websites
and books cite it as fact. Grrrrrrrrrrrrrrrrrr.

Incidentally, if you don't have a copy of "An Album of Fluid Motion"
by Milton Van Dyke, get it. You'll love it. Every gliding club should
have one.

Ian

[Martin Gregorie[_4_]]

On Sat, 21 Mar 2009 12:28:59 -0700, The Real Doctor wrote:

> Incidentally, if you don't have a copy of "An Album of Fluid Motion" by
> Milton Van Dyke, get it. You'll love it. Every gliding club should have
> one.
>
Another recommendation:

http://www.av8n.com/how/ gives a good description of how an aeroplane
works. A lot of it is similar to "Stick and Rudder", so its written for
pilots rather than aircraft designers. However, section 3 has excellent
descriptions and diagrams showing how a wing works. It was recommended to
me by a professional aerodynamicist who is a model designer and has flown
gliders.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Martin Gregorie[_4_]]

On Sat, 21 Mar 2009 20:01:23 +0000, Martin Gregorie wrote:

> On Sat, 21 Mar 2009 12:28:59 -0700, The Real Doctor wrote:
>
>> Incidentally, if you don't have a copy of "An Album of Fluid Motion" by
>> Milton Van Dyke, get it. You'll love it. Every gliding club should have
>> one.
>>

Here's a link to animated visualizations of the flow past a wing:
http://www.av8n.com/irro/ - click the flag of your favored language to
see the visualizations.

--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[The Real Doctor]

On 21 Mar, 20:18, Martin Gregorie >
wrote:
> On Sat, 21 Mar 2009 20:01:23 +0000, Martin Gregorie wrote:
> > On Sat, 21 Mar 2009 12:28:59 -0700, The Real Doctor wrote:
>
> >> Incidentally, if you don't have a copy of "An Album of Fluid Motion" by
> >> Milton Van Dyke, get it. You'll love it. Every gliding club should have
> >> one.
>
> Here's a link to animated visualizations of the flow past a wing:http://www.av8n.com/irro/- click the flag of your favored language to
> see the visualizations.

I've never really liked that Joukowski transform stuff. The arbitrary
definition of circulation worries me, and anyway no real wing behaves
anything like that. It's a fair way of visualising the flow, roughly,
but I prefer to jump straight into circulation theory and model my
wings as vortices.

Ian

[Tech Support]

UF

Don't bitch.The P-51, with Merlin engine, had one set of tools for
engine and another set for airplane. That was back in 40's (WWII) :o)
Crew chief carried two bags when he went to work on bird.

Have a nice Day.

Big John



On Fri, 20 Mar 2009 20:17:15 -0700 (PDT), Uncle Fuzzy
> wrote:

>On Mar 20, 4:58*pm, Doug Hoffman > wrote:
>> Bob Kuykendall wrote:
>> > On Mar 19, 6:08 pm, Doug Hoffman > wrote:
>>
>> >> I just wish the US would perform its conversion to metric units for
>> >> *everything*. *The sooner the better. *But that job is being handled by
>> >> our highly efficient government. *Don't hold your breath. *:-)
>>
>> > Kind of a hijack, but what I wish is that aircraft hardware
>> > manufacturers would get their crap together and produce a coherent
>> > metric equivalent of the AN system of common aircraft hardware.
>>
>> > The magic of the AN hardware system is not that they offer any
>> > particularly high strength (they don't; for the most part AN bolts are
>> > equivalent to Grade 5 hardware store bolts) or any particularly high
>> > precision (again, they're about the same as the bolts at Ace or True
>> > Value). The magic is that AN bolts have just enough thread for a nut
>> > and somewhere between 0" and about 0.125" of washers, and that they
>> > come in length increments of 0.125". Those two elements let you create
>> > a nice, tidy bolted joint of virtually any practical grip length, and
>> > not have the threaded portion of the bolt loaded in shear, and not
>> > have a bunch of threads hanging out of the nut. Furthermore, common AN
>> > hardware is very attractively priced, for the most part you can buy
>> > them from any of several aircraft parts outlets at the same or even
>> > lower prices as Grade 5 bolts at a mom&pop hardware store.
>>
>> > By contrast, metric aircraft hardware has no coherent system of
>> > markings, thread lengths, and grip lengths. It averages twice or
>> > thrice the cost of AN hardware when you can find it, and is available
>> > from only a few outlets. When you need a replacement bolt for your
>> > European aircraft, you have virtually no choice but to order it
>> > directly from the manufacturer at huge markups and with huge shipping
>> > charges.
>>
>> > I like the metric system, and I like metric hardware. I appreciate
>> > that even American cars are, by and large, assembled with metric nuts
>> > and bolts these days. But given the choice between about $500 worth of
>> > AN hardware per aircraft and twice or thrice that in metric nuts and
>> > bolts that offer no greater utility, hmmm, I think I'll go with the
>> > less expensive option.
>>
>> > End rant.
>>
>> Hi Bob,
>>
>> Yes. *There may be some niche areas like aircraft hardware that would at
>> least require legacy support for a period of years. *Makes me wonder
>> what Boeing/Cessna and others are doing now and plan to do in the future
>> in that respect.
>>
>> Regards,
>>
>> -Doug
>>
>> Btw, American designed cars and trucks do more than just assemble with
>> metric fasteners. *Nominal dimensions are typically, e.g., 100 mm for a
>> bracket width instead of 4.0". *We call that "hard metric" design. *Some
>> user interface items like wheel lug nuts may still be SAE.- Hide quoted text -
>>
>> - Show quoted text -
>
>While we're 'Ranting'.... Bob, that would be nice, wouldn't it? It
>took me 2 tries to get the right bolt from Grob when I went throught
>my control system a few years ago.
>DON'T get me started on US auto makers. I have two Dodge Trucks. I
>HATE the fact that evey time I get under one to work on it, I need to
>take BOTH metric and SAE tools. Pick a STANDARD! My favorite example
>was an exhaust stud on a 1998 Olds Intrigue. Engine side - SAE
>exhaust flange side - metric.
>Rant off.
>I feel better now.

[The Real Doctor]

On 21 Mar, 23:35, Tech Support <> wrote:

> Don't bitch.The P-51, with Merlin engine, had one set of tools for
> engine and another set for airplane. That was back in 40's (WWII) :o)
> Crew chief carried two bags when he went to work on bird.

The Citroen 2CV came with two (I think, may have been three) spanners
which allowed you to do anything up to and including a full engine
rebuild.

Ian

[Uncle Fuzzy]

On Mar 21, 7:12*pm, The Real Doctor > wrote:
> On 21 Mar, 23:35, Tech Support <> wrote:
>
> > Don't bitch.The P-51, with Merlin engine, had one set of tools for
> > engine and another set for airplane. That was back in 40's (WWII) :o)
> > Crew chief carried two bags when he went to work on bird.
>
> The Citroen 2CV came with two (I think, may have been three) spanners
> which allowed you to do anything up to and including a full engine
> rebuild.
>
> Ian
The P-51, however, at least had the excuse of being a wartime
project. GM, Chrysler, and (I assume) other US automakers don't have
that going for them. They really do need to pick a standard and stick
with it.
.... and I can do everything short of a bottom end rebuild or tranny
rebuild on my 36 year old BMW motorcycle with the tools in the stock
tool kit plus a torque wrench.

[Mike Schumann]

That is a VERY good reference!!!

Mike Schumann

"Martin Gregorie" > wrote in message
...
> On Sat, 21 Mar 2009 12:28:59 -0700, The Real Doctor wrote:
>
>> Incidentally, if you don't have a copy of "An Album of Fluid Motion" by
>> Milton Van Dyke, get it. You'll love it. Every gliding club should have
>> one.
>>
> Another recommendation:
>
> http://www.av8n.com/how/ gives a good description of how an aeroplane
> works. A lot of it is similar to "Stick and Rudder", so its written for
> pilots rather than aircraft designers. However, section 3 has excellent
> descriptions and diagrams showing how a wing works. It was recommended to
> me by a professional aerodynamicist who is a model designer and has flown
> gliders.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

[Martin Gregorie[_4_]]

On Sat, 21 Mar 2009 16:01:33 -0700, The Real Doctor wrote:

> On 21 Mar, 20:18, Martin Gregorie >
> wrote:
>> On Sat, 21 Mar 2009 20:01:23 +0000, Martin Gregorie wrote:
>> > On Sat, 21 Mar 2009 12:28:59 -0700, The Real Doctor wrote:
>>
>> >> Incidentally, if you don't have a copy of "An Album of Fluid Motion"
>> >> by Milton Van Dyke, get it. You'll love it. Every gliding club
>> >> should have one.
>>
>> Here's a link to animated visualizations of the flow past a
>> wing:http://www.av8n.com/irro/- click the flag of your favored language
>> to see the visualizations.
>
> I've never really liked that Joukowski transform stuff. The arbitrary
> definition of circulation worries me, and anyway no real wing behaves
> anything like that. It's a fair way of visualising the flow, roughly,
> but I prefer to jump straight into circulation theory and model my wings
> as vortices.
>
You're way beyond me there. I can choose suitable, matched wing and tail
sections for competition free flight models, which requires some
understanding of Rn effects and the usual section performance diagrams
and data. I also know a little about the use of turbulators and tip
shapes. As I've ended up with decently performing and stable, flyable
models I must be doing something right. However, thats as far as I go.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |