old man emu

A bit of semantics here.

We think of pressure as a positive force and see it when we introduce air into a tyre. We increase the pressure of the air inside the tyre and we see that pressure force the tyre to change shape. In this case we measure the difference between the force exerted by the atmosphere (1013 hPa, or 14.6 lbs/sq in, or 29.7 in Hg at seal level) and the pressure exerted by the introduced air on the inner wall of the tyre.

If we go the other way we can reduce the pressure within a container to below that of the outside air pressure. We call the difference between the outside atmospheric pressure and the inside of the container, a vacuum, and the way we reduce the pressure is to suck. The engine sucks air by increasing the volume of a cylinder by moving an "airtight" piston from the top to the bottom of a cylinder. This movement, when timed with an open intake valve draws air from the atmosphere, through the intake manifold to the interior of the cylinder. If you introduce the inlet of a pressure gauge into the intake manifold you can measure the pressure exerted by the moving air. 

The drop in pressure is due to the venturi effect, although an intake manifold does not look like the venturi tube we are more familiar with. In fluid dynamics, an incompressible fluid's velocity must increase as it passes through a constriction in accord with the principle of mass continuity, while its static pressure must decrease in accord with the principle of conservation of mechanical energy (Bernoulli's principle). Thus, any gain in kinetic energy a fluid may attain by its increased velocity through a constriction is balanced by a drop in pressure.

As an expert in creating poorly worded questions, I suggest that the question should be reframed, but I don't know what the correct question should be. 

For those who don't like to live on a knife edge.

Evans Head Airpark Pty Ltd is still a registered company.

Is this mob still active? https://ehham.org.au/

From The Northern Star  23rd December 2009

Evans Head Airpark Pty Ltd is headed up by a team of high-profile people.

They include Peter Lynch, president and chief executive of Waratah Coal, whose company is involved with the Galilee Basin mining project. If approved, it would be one of Australia’s biggest mining projects, worth $7.5 billion.

Former Olympian and champion ironman Grant Kenny is also part of the consortium. He is the owner of the nation’s largest private aviation operator, the Curry-Kenny Aviation Company.

Other team members include Red Bull air race pilot Matt Hall, accountant Duncan Cornish, environmental professional Mark Imber, communications firm director Andrew Crook and aircraft maintenance engineer Mark Radford.

Their proposal incorporates at least 60 exclusive homes with direct access to flying facilities and an industrial complex for aviation-linked businesses.

It would also have a museum, private hangar space, a motel, convention centre and camping facilities.

That was then. what is the plan now?

I would have thought that the authorities should have looked at the baby to determine race. That would eliminate many of the women. I dare say that a woman who has just given birth isn't going to be able to stand in a line for very long.

I bet most of the women's fear was due to not knowing why they had been called out. I bet most of them thought that there had been a revolution or some strange misogynistic command had come from a radical religious leader. I bet the women's menfolk were panicking too.  

Monstrous metaphors. Pernicious puns. Sympathetic similes. Malevolent malapropisms. Spontaneous spoonerisms. 

It all comes from my DNA. An early ancestor in the Jurassic dined regularly on Thesaurus.

That post is an insult to sentient beings!

Dealing with airport noise is itself a headache for airport operators. The Bankstown Airport Master Plan Chapter 5  Page 43 and following goes right into this subject.

https://smafiles.blob.core.windows.net/balmasterplan2019/191128_Bankstown Airport Masterplan-Final_C_web.pdf

Studies of aircraft noise impacts presented for Bankstown Airport were carried out using the United States Federal Aviation Administration-approved Integrated Noise Model (INM) Version 7.0d. This internationally recognised, computer-based noise simulation model calculates contours from an analysis of the contribution the various defined aircraft and their operations have on the overall noise emissions from the Airport. The resulting noise ‘footprint’ can then be used to assess the relative impacts that different aircraft and operational procedures have on the surrounding area.

Wanting to be able to fly is the albatross around my neck. 

Now we'll see who knows what a DCM is. 

49 minutes ago, kasper said:

You'd have to do this in RAAus becuase the CASA guy/gal faced with this nightmare will run screaming in the distance when you try to explain its a 6 motor fly-by-wire autostabilised magnus effect lifting device with no wing area and no stall speed cobbled together in my garage and managed with $300 of electronics from Hobby King I programmed up on this laptop 😁

 

Ha Ha Ha!

Have a look at the KFC video to see how he gets the drums rotating. I see your point about having each drum powered independently in order to provide roll movement.

From the video of the KFC buckets I formed the opinion that the engine should be a pusher, and set out like the Royal Aircraft Factory FE2D

The video also indicated that there needs to be a lot of weight forward of the CofG. Perhaps the everything forward of the cylinders could be set out like a regular plane, and the pusher prop driven by a shaft.

Kasper has found the flaw in the otherwise flawless plan - if the drums stop spinning there is no Lift. Fortunately we now have recovery chutes. They would need to be an essential component. 

Once again the meeja starts bashing aviation. When was the last time it published anything about "petrol heads" altering their cars' exhaust systems for more noise, or the lack of silencing on motorcycles? 

I live on a minor feeder road in a residential area. It has a 50 kph speed limit, but that doesn't stop people creating a hell of a lot of noise as they race from one roundabout to the next. Poorly silenced, high revving engine are a constant annoyance. I can even hear vehicles dragging off from the traffic lights on the main road half a kilometre away. Now and again, a light aircraft will overfly my place, or I can hear the glider tug clawing its way to release height. The difference is that aircraft pass over my home with their engines set at a fixed speed, so the noise is a steady drone, and from more than 1500 feet away. 

I should also mention the noise from whipper snipers, grinders powered saws etc that my neighbours (and me) use.

There is an old saying, caveat emptor, which basically means "do your research before you buy". If you are going to buy or rent in an area, find out the sources of noise if you are noise-sensitive.

Here's how the FAA handled a complaint from a member of the public based on videos posted on Youtube.

Summer's coming and we'll see lots of polishing of cricket balls so that the bowlers can get lateral movement through the air. How so?

The principle the cricketers are depending on is the Magnus effect. The Magnus effect is an observable phenomenon that is commonly associated with a spinning object moving through the air or another fluid. The path of the spinning object is deflected in a manner that can be explained by the difference in pressure of the fluid on opposite sides of the spinning object.

This effect has been used in the past to replace the wings, or rotors of an aircraft with cylinders. 

On a cylinder, the force due to rotation is known as Kutta-Joukowski lift. The lift on the cylinder per unit length, F/L, is the product of the velocity v (in metres per second)  of the aircraft relative to the airflow, the density of the fluid, ρ (in kg/m3), and the strength of the vortex that is established by the rotation, G.

F/L= ρ.v.G

where the vortex strength is given by

G=(2.pi r)^2.s

or,

= (2.pi r)^2.ω

where s is the rotation of the cylinder (in revolutions per second), ω is the angular velocity of spin of the cylinder (in radians / second) and r is the radius of the cylinder (in metres).

To maintain a constant height, F (Lift Force) must equal the weight of the aircraft, so:   F = L.ρ.v.G, and to climb, F > L.ρ.v.G

Can this effect be applied to aircraft? Well, yes. Sort of. The Plymouth A-A-2004 was built in 1930 by three anonymous American inventors, and was reported to have made successful flights. 

Once again, this early experiment was probably hindered by the available engine technology of the time. Some young experimenters have used this method for generating lift for RC test beds. Here are two videos that show that flight can be attained using the Magnus Effect.

This first video is a bit of fun, but shows some of the engineering problems that need addressing to perfect the rotation of the cylinders. The choice of cylinders may also adversely affect the result. 

Once the thing is flying, you can see that work is required to get the aircraft to fly more tail up in a normal orientation to the ground.

This video shows another application. This time the flight is better, but the video lacks the technical background of the first.

I've been watching this bloke's videos for some time, mainly starting with his crazy RC stuff, but I can across his latest ones which show his current ultralight aircraft.

It is an interesting construction - poplar wooden frame for the rear fuselage; chromoly tubing for the forward section. He first used an ICE from a para-glider, but later on installed an electric motor.

His wings are made from cut out foam, covered with a type of vinyl. Unfortunately, his videos are lacking in discussion of technical details, but at least he goes to the trouble of testing his idea with scale models before he commits to the final build. His building techniques are quite good and worth watching. I like his wing construction method.

The video link I'm posting here is of his latest plane, but I recommend that if what he has done interests you, you search out the videos of his earlier attempts to see the evolutionary process he followed to get to this latest one.

INITIAL GROUND RUNS AND MAIDEN FLIGHT

WINGS: Go to about 2:00 minutes

Possibly one of the reasons that CASA people are out of touch with GA people is that a lot of the CASA people seem to be retired RAAF people whose experience comes from an environment where rules were rigidly followed and where the cost of replacing things did not matter. Their experience seems to have been "If it's broke, chuck it and put in a new one". They never had to deal with the economic realities of life in the public sector. It seems that their ability to sort out a problem only extended to testing to see if an item does not function. There is no need to understand how the item works so that they can get inside it and fix it. This then flows over to the development and administration of regulations.
 

17 hours ago, skippydiesel said:

how about an electric step motor,

But with that you will need a stepper driver for precise movement. Not a weighty thing, but something more to erode MTOW and to require maintenance.

Remember KISS, and not the mob made for lovin' you.

Isn't there some performance line in the sand where a CSU is no better than a fixed pitch prop after all factors have been taken into account? Cross that line and the CSU wins. I would have thought that the factors one would look at are engine torque and airframe Vne. Then one would consider the weight trade off and the extra maintenance costs.

There is sometimes reluctance to promote a particular supplier of a product as it may seem to be touting for business. I've done it a lot, but I've got a thick hide, and am used to having quiet discussions with Ian about how I have sinned. Others might not feel so game. (Strewth, there's some Big Game Hunter metaphors there.)

There are some things about which we ask, as Facthunter does, 

Props come into that category. Design and manufacture of efficient props takes a lot of knowledge and experience, whereas other jobs around building an aircraft-  riveting; stitching; assembly - are simply abilities that can be taught in a short time and competency comes quickly. Best to leave propeller design to those working in conjunction with the engine designers

But there I go - wandering off onto another track while poor SkippyD waits for an answer to a question about propeller suppliers & their products. 

That ^ is definitely something that should be bookmarked. 

During war, everybody tries to examine the other bloke's weapons. It doesn't matter if the other bloke is your ally or your enemy. You are always on the lookout for something better.

During the middle stages of WWII, the Luftwaffe had a look at the fighters that Italy was using. Obviously if there was anything good amongst them, Germany could have contracted for the manufacture of the good stuff to bolster its own needs. This video gives the results of that investigation. What stands out is that, although one or two Italian aircraft were pretty good, or could be readily upgraded, the German desire for fighter-bombers instead of all out fighters lead them to discount the Italian planes. The cause was most often that the Italians put their radiators in the middle of the lower surface of the fuselage, thereby taking up the space for bomb racks.

On 21/10/2020 at 9:27 PM, old man emu said:

Kyle at Aviation Welding at Bankstown

You'll not only get the product you want, but Kyle has years of practical experience gained from undertaking a myriad of metal construction tasks. 

Just remember to throw the toy for his dog and scratch it behind the ear.

8 hours ago, Yenn said:

The most dangerous loading was max weight with min fuel, which would put you out of safe C of G quite easily.

Not being silly, but isn't that a condition that you could reach at the end of a long flight?  But by then the weight  would have reduced due to fuel burn, so the CofG might have moved, but still be within the envelope, wouldn't it?

3 hours ago, skippydiesel said:

engage the services of a suitably qualified/experienced person.

I recommend that you go talk to Kyle at Aviation Welding at Bankstown. He's probably the only person in Sydney who is approved by CASA to do aviation welding and who can be easily spoken to. Did you know that he has to pass regular competency examinations by CASA to retain his approval?

These are the hoops he has to jump through to retain his approval. 

33_1 (2).pdf