old man emu

Aw, Gee! Mine were!

Can you pull those across?

Wasn't there one on the other site? I know I've posted a couple somewhere.

Are you going to migrate the data from the earlier book section?

On 30/09/2020 at 10:55 AM, red750 said:

Whatever happened to New Zealand's Martin Jetpack?

The Company crashed and burned in 2019.

https://www.nzherald.co.nz/business/news/article.cfm?c_id=3&objectid=12231984

47 minutes ago, facthunter said:

pilots should be prepared to pay for the use of an airport at a fair rate subject

That sounds fair. We pay to use non-toll roads through levies included in vehicle registration fees. But there are millions of vehicles contributing to building and maintaining roads in that way. Unfortunately, successive governments have stifled the aviation sector that would use those small country town airfields.

It looks like a nice airfield, and only about 2 kms from town

On 23/01/2019 at 12:11 PM, spacesailor said:

THE FIRST H BIRD VIDEO I SAW:

Spacey,

What was the story with your attempt to get a Hummelbird on a register.  I've come in late on that and only know that yours is grounded.

11 minutes ago, facthunter said:

You run a plug SUITABLE to the engine

Too right. You know that, and I know that, but are we going to start a new thread to educate the masses about spark plug design considerations?

Not a resource for incredibly wealthy aircraft owners, but a District's means of access to lifesaving transportation.

They ought to be congratulated!

5 hours ago, yampy said:

The BOM site showed gusts of 64KTs , the same wind speed that flipped a C172 onto its roof at Camden last week .

I told you when we were talking about X-wind components of a wind that a plane would fly if the wind speed was higher than the stalling IAS.

But do you run a hot plug in a cylinder that runs hot, or do you run a cold plug in a cylinder that runs hot. 

When you first encounter the terms as applied to spark plugs, you have to delve a bit deeper into learn what these terms mean for  the engine. Initially it's not quite quite the same as "I can touch something that is cold, but will be hurt by something that is hot".

The Republican Part (the GOP) was founded in 1854 by opponents of the Kansas–Nebraska Act, which allowed for the potential expansion of slavery into the western territories. The party supported classical liberalism, opposed the expansion of slavery, and supported economic reform. After 1912, the Party underwent a social ideological shift to the right. Republican Party ideology is American conservatism, which incorporates both economic policies and social values. The GOP supports lower taxes, free market capitalism, restrictions on immigration, increased military spending, gun rights, restrictions on abortion, deregulation and restrictions on labour unions.

9 minutes ago, facthunter said:

Why is the subject confusing

Not confusing when you have learned what "hot" and "cold" relate to, but what was you understanding when, as a pimply faced 1st Year apprentice, you first heard people taking about hot & cold plugs. The descriptors are counter-intuitive.

Methinks this topic needs a thread of its own.

24 minutes ago, kgwilson said:

I+nternational trust has been eroding for a long time now and based on the international press reports today, it has largely disappeared. If Trump does lose and he can get his disaffected supporters to rally in support their descent into chaos will be complete,

I said some time ago that empires only have a relatively short life span before internal dissent and power plays rot them from the core, allowing other outside groups to break through the protective walls. The Ancient Middle Eastern empires lasted for long times because of the low speed of transport and communication. Since 1800 we have seen these two things speed up and he lives of empires shorten.

Are wwe seeing the beginning of the end of the Empire of the USA?

1 hour ago, facthunter said:

Never have I seen a suggestion to use colder plugs. for instance. Anyone with very white insulators in any engine may be running too hot a plug and risking engine damage. Nev

Whoa! Not that there is anything wrong with what you have said, but you've opened the hangar doors on a confusing subject when talking about hot and cold spark plugs. 

The term hot/cold is commonly used to describe whether a spark plug itself does not conduct heat away from the tip, and heats up easily (hot) or whether it does (cold). The numbers in the diagram are determined arbitrarily by the spark plug manufacturer. They are not standard in the industry. You have to use a comparison chart to see if, say an NGK plug is in the same heat range as a Champion. The manufacturer's recommendation for my bike's plus is a Harley-Davidson Number 4, but since I can't get the OEM ones, I used a Champion Number 14.

An interesting note about my bike's spark plugs. Since the cylinders are in line, one behind the other, it is recommended that a cold plug is used in the rear cylinder, and a "hotter" plug in the front when the bike is used for highway speeds.

I wonder what effect that would have on the operation of an aero engine if "hotter" plugs were fitted to the cylinders that showed higher CHT's.

These are the variations in weight he is talking about

What common thing can you use to get an idea of these differences? A spoonful of sugar, not only helps the medicine go down, it weighs 4.8 grams.

He raises an interesting point for discussion. In theory one would think that making parts they way these people did would produce identical products, but when practice sticks its grubby finger into the pie perfect repeatability goes out the door. Unfortunately there are only two of each component, which makes useful statistical analysis impossible. If there were twenty or more of each component to add to the data then some practical use could be made of the analysis.

These people are being influenced by the accuracy they are getting from CNC and 3D-printing. If I could make several different components and come as close to identical as they have, I'd be happy.

I don't think that a ballistic chute would be a life saver as these things are only meant to operate to just above tree-top level at best. The biggest draw-back is the lack of range. While very good in the thrust/rate ratio, the fuel consumption makes them ineffective for anything other than short hops. I doubt if even an electric fan jet as used in RC planes would make this type of machine practicable.

I don't think that those things on his arms are anything to do with the actual thrust. If you look closely at the ground, the grass is not flattened in front of him, only behind. Also, as he waves his arms around, his body is not pushed in the opposite direction. When in the air, his arms are in different positions in relation to his body, but he flies straight. It seems that the turn is made by weight shift.

They certainly have taken a lot of effort to document the build. And they are really looking into the gnat's nuts of it.

I liked this video 

RAAus - get back to basic flying!

But I want the electronic whizz-bangery of a long haul heavy.

Compromise, compromise. It's always a compromise.

And for the slight performance advantage of a CSU, the weight and extra complexity are hardly worth it in a plane that cruises below 100 kts.

Am I correct in saying that Thrust is a force acting along the fore/aft axis of the plane? Therefore a very simple and rough way to measure Static thrust would be to tie the plane to a building with a weighing scale included between the building and the plane. Then apply thrust at various engine RPM from idle to full power and record what the scale is showing.

On 25/09/2020 at 5:16 PM, facthunter said:

Not many of our planes actually NEED a CS prop They don't go fast enough..

True enough, but would you say that the engines of "our planes" don't have the wide range of horsepower output that the CSU takes advantage of?

Would you agree that a CSU performs a similar function to a car gearbox in making the best use of the available horsepower?

I hate talking about horsepower. I would rather go to the more basic level and talk about torque. Torque is simply a force acting on something from a distance (i.e. a piston pushing down on a crankshaft, using that leverage to rotate it), while horsepower is torque multiplied by RPM, or a measurement of how quickly that torque can be applied to do work.

Torque, also referred to as a moment of force, is a measure of rotational force and is quantified as force x distance, where distance is measured perpendicular from the axis of rotation. In imperial units, the unit of measurement is the pound-force foot (lbf. -ft.) In metric  it is Newton metres.

.

In practice, the amount of torque that a particular engine installed in its place of employment produces varies with the amount of fuel/air mixture introduced to it (how far the throttle is pushed).

Horsepower is a measure of how much Work can be done in a unit of time.

Work = force x (distance an object is moved), In calculating horsepower in a rotating system such as a piston and crankshaft, velocity of the crankshaft is used. That velocity is reported as Revolutions per minute (RPM).

Horsepower is the product of torque and rotational speed of the crankshaft

HP = Torque x RPM

Since the units of Torque and RPM don't match, a conversion factor is required so that the answer is reported in Watts or ft lbf/min

So, for Imperial units HP = (Torque x RPM)/5252

The only time that we like to avail ourselves of all the HP an engine can produce is during takeoff, but I wonder if relying blindly using full throttle at takeoff, then reducing power a short time after rotation is a major cause of EFATO. (Meat for another thread)

5 minutes ago, red750 said:

Bit surprised this was approved

Dyslexic public servant thought it was FUNK.

2 hours ago, RFguy said:

drop a rope and get dragged in on a drum winch ?

At that wind speed the rope would be standing out like a WWl fighter pilots silk scarf

Getting back to windsocks. If the sock is full, it means that the wind speed is equal to, or greater than 15 kts. From then on, it is only good for indicating wind direction. But I suppose commonsense (remember that?) would tell you to rely on drift as an indicator of windspeed. But who would like to go and play in a 15+kt crosswind?