APenNameAndThatA

19 hours ago, old man emu said:

This is one of those diagrams that I say is causing confusion:

While this is a totally correct way to explain why the pilot has to take action to increase the resultant lift in order to complete the desired manoeuvre, it does not illustrate how the relative airflow moves around the wing.

 

Here is a scrappy diagram of what I am getting at.

The rectangles represent the leading edge of a flat plate. The red dots represent the airflow meeting the leading edge, and you can assume that the air diverts over and under the wing as we know it does.  In order to get a bit more Lift force we'll arbitrarily assign an AoA of 4 degrees. I don't have the CAD software to draw that in a diagram. Imagine that the plate is connected to some device that measures the magnitude of the Lift force, and that device allows us to tilt the plate around the halfway point of the span. I have drawn the lower rectangle with a 20 degree tilt down with respect to the top one - simply to fit the diagram on a page. 

 

Now if we pass an airstream (relative airflow), having a known velocity and density of the air, at the top rectangular plate, a Lift force will be generated, which we can depict as an arrow pointing upwards. Our measuring device can tell us the magnitude of that force. Next, without changing AoA , airflow velocity or air density, we tilt the plate away from the horizontal and again obtain a value for the magnitude of the Lift force. The two magnitudes will be the same. 

 

In other words, the angle of the plate relative to the horizontal datum will not affect the magnitude of Lift force generated by the plate. This is because no matter how the plate is orientated in relation to the horizontal datum the density and velocity of the relative airflow are the same. The plate is immersed in the fluid the same way that a fish is immersed in the sea.

 

It is incredibly hard to produce a two-dimensional diagram of this, that's why I said to use a three-dimensional object to help envisage what I am saying.

 

If this plate was set up at 90 degrees to the horizontal datum, would the Lift force be the same as in the other two cases? Yes, but when one wants to use that Lift force to balance the weight force of an aircraft, there is no vector component that is equal and opposite to the weight force. aro mentioned at one point that the horizontal vector of the Total Lift force is used to turn the aircraft. When the wing is at 90 degrees vertical, one would guess that it's all turn and no holding altitude. 

 

Phew!

 

 

So OME, you've got some great info about what happens to the lift of the wing when someone is doing a hesitation roll. Would you care to summarise it for us? 

20 hours ago, onetrack said:

If you looked, you'll see the original poster is located in the USA. CASA has no power in the USA, his aviation authority is the FAA.

Duly noted. 

On 28/03/2021 at 6:02 PM, shafs64 said:

OK who is Wolf Warrior.

China, I believe

It’s not easy when you’re really clever and no one believes you. 

On 18/03/2021 at 12:03 AM, pmccarthy said:

https://aopa.com.au/opinion-no-spin-just-a-spiral-dive-in-casa-ethics-and-conduct/?fbclid=IwAR11fgyOnQVkMGlSUqG0qste6oWEk-LMAcT8vHde60oBSKSGUxOw0yU0YIU

I am surprised at that, to say the least. Got a problem with a plane? Hire a test pilot to examine it. Simples. Or am I missing something? 

In the video, the first stall he loses 500 feet, and the second one 400 feet. And a wing drops about 45 degrees. Not good. 

On 28/03/2021 at 10:49 PM, walrus said:

Just watched a Youtube video of the factory test pilot demonstrating stalls in a Bristell. By his own words each recovery took of the order of four hundred feet and the video shows a wing drop on each stall.

 

400' is too much compared to the GA standard for a C172/ PA28 of one hundred feet altitude loss. Such a loss also means that an error in recovering the dropped wing at circuit height is going to be fatal because it will delay recovery if not stimulate an incipient spin.. In my opinion and I'm not an expert, this is not an ab initio trainer by any stretch of the imagination.

 

 

400 feet by a *factory* pilot AND the stick forces are wrong!? And it’s legal to fly at 500 feet over unpopulated areas, right? If the above is even half true it does not look like CASA will be on a witch hunt no matter what they do. 

I would ask CASA. When I asked then about landing in the desert they were sensible but a tiny bit non committal. I would avoid the forgiveness rather than permission approach.  

I would test on the ground and in the air. And check that the smoke is visible from the ground. 

I would have a separate person to operate the canister so that the pilot can just fly the plane. I would use at least two canisters in case one failed. 

I would have predetermined, written minimums that someone would hold me to because if you are the gender reveal centre piece the get there itis will be intense. Make sure the party host has a canister of there own in case you cannot fly that day. 

Don’t use a system to hold the cannisters outside the airplane to get around rules about attaching stuff to the airplane. You might drop the canister or fill the airplane with smoke. 

DISCLAIMER   I have 119.1 hours and know *nothing* about this topic. 

And this from someone who says that they do not think that they come here to teach people. " I just try to expose general misunderstandings."

"Prior to beginning the roll, the aircraft is flying with its wings parallel to the Earth's surface."

Wrong. The two planes will be at the angle of attack (assuming that the manoeuvre starts with the airplane straight and level, which is a reasonable assumption. By "planes" I mean the flat plane of the earth's surface and the plane of the wing, defined by the theoretical plane formed by the chord and the span of the wing.

Actually, on reflection, even that is untrue, unless there is no dihedral. Airplane wings with dihedral are not parallel to each other so there is no chance that they will be parallel to the surface of the earth. 

And this, "Yes. But first I want to get people to really think, and to question what they believe." The idea that you don't think you are here as a teacher is laughable. 

Also, as someone might, and might not have said, if a plane does an aileron roll, the AoA will change unless the roll axis is exactly parallel to the angle of incidence of the wind. I don't think you can guarantee that. For example, in an Extra, before you do an aileron roll, you point the nose up a bit. I expect that the nose is up a bit during the whole aileron roll. That means that when inverted the wings will be providing negative lift (lift against gravity) and when the aircraft is on a knife edge, the AoA could be zero. That would mean that at 45% the AoA would have decreased a little. 

Also, a particular pilot in a particular aircraft, might adjust the elevators as they complete the roll. 

So, there is every reason to believe that the wing will be producing less lift during the roll. Your answer assumes that the AoA is the same at 45° bank as at 0° bank, which is wrong. 

Can I show you where you purported to be a teacher? How about this quote. 

"I really do give up. No matter how much I try to clarify and have people's attention hone in on the point I'm making they have to go past the point I want to stop at."

If I recall correctly, you complained that by posting here you were casting your pearls before swine and giving what is holy to dogs. Correct me if I got the bible quote wrong. 

This is ludicrous. You are presenting yourself as a teacher on this forum when you believe a) That a spirit level can be used to measure angle of attack and b) something with a weight of 3 kg has a mass of 0.3 kg. It would be fine, except some people will believe what you write. The more well-respected posters to this forum should not stand for it. 

4 hours ago, planedriver said:

For those among'st us that like flight simulators, be grateful of the progress that has been made in recent years.

After all, you could be trying to learn how to fly on learn on one of these.

Superb boots. 

10 hours ago, rankamateur said:

Did you try in an adjustable seat model or the original seat layout. I am a long bodied 189cm and fit quite comfortably in the standard seat. We fitted a 6' 9" bloke in an XL at Bundaberg airshow. He had more head space than I do but was a bit tight around his knees under the dashboard. Adjustable bucket seats are a whole different story!

I was sitting on the aluminium bench that is built into the plane. Maybe there is more to this than I am aware of. Also, i was wearing a helmet. Not that it adds too much height. 

On 20/03/2021 at 8:15 PM, Ace747 said:

Greetings guys. 

Was just checking in to see if anyone knows of a RA-Aus flying school who needs a helping hand for the next year or so in NSW, Queensland or even SA? 

Ive worked at 10 flying schools over a 25yr period, instructing on a long list of various aircraft ranging from rag and tube Drifters, X-airs, Thrusters, Bantums right through to more current  trainers such as Foxbats, Jabirus, Tecnams, etc. 

 

I would appreciate any suggestions if you have one. 
kindest regards

Peter

[email protected] 

Why do you keep moving? 

I know of someone who copied a prop. They had a cutting wheel and a guide wheel of the same diameter attached to something like a jig and used an existing prop to make a new prop. Kind of like a giant, 3D pantograph. At least that's what they said they did. 

On 07/02/2021 at 7:55 AM, Mike Gearon said:

My first landing French Island. 

 

Happy to have visitors for a cup of tea and scones in the workshop/ hanger once I've sorted. Not yet! Going to get a road grader in to smooth better  and remove a bit more fencing either side of strip. It goes up and downhill so an interesting challenge. Will remove more trees for next landing and that'll allow a much lower approach.

 

https://youtu.be/QRWdfhP7fbM

What’s the black box to the left of the panel. My Foxbat has the same space and Im wondering what to fill it with

1 hour ago, pmccarthy said:

It is interesting because Bristell is still on my list of possibles and if they are wrongly disparaged (as Jabiru were) then they may become a great value buy.

They will be great value either way. Just make sure you don’t stall. 

On 11/03/2021 at 4:45 PM, IBob said:

I think he's looking for a detailed drawing, with dimensions, for the firewall, Mark?

zapora translates as dam, and zapora ogniowa is firewall...according to Google...

Polish. If anyone wondered

12 hours ago, pmccarthy said:

It makes me sad that we have trolls here. I enjoy everyone's contribution, but there is no need for the trolling which in the end will destroy this site. It isn't new, it has happened on and off for a decade. Good wishes to all.

I think we have a duty to not let people state false things as fact, mislead other people and not be pulled up about it. 
 

Not long ago, I said that I had a *theory* about when to respond to something as a stall and when to respond to it as a spin. Someone replied that someone could die if they read what I said and acted on it. That was not the end of the world. 
 

When I post something that is wrong, I welcome the correction. Like when I conflated mass and inertia. I value negative feedback. It’s unpleasant but valuable.
 

I recognise that a number of people here think I’m a troll and therefore not good for the site. I honestly don’t know what to do about that, and welcome suggestions. One alternative is having a site that recommends using spirit levels to measure angle of attack. 
 

Is there a way to have a site that does not recommend spirit levels to measure angle of attack and does not make multiple  members feel there are trolls? 
 

(A troll is someone who acts in bad faith, which clearly I am not. But the point is that people find what I was posting unpleasant.) 

4 hours ago, old man emu said:

OK. You and your mate have won. After years of trying to make positive contributions to this site and its sister site you and your mate have succeeded in your goal to stop me doing so. Therefore, I am going to withdraw from the field completely. The time I have spent preparing my posts for several parts of this forum will now be spent doing things for people who appreciate the effort.

 

I shall follow the advice of the Judean philosopher, Jesus of Nazareth as recorded in Matthew 7:6.

I suggest you spend your time learning from a qualified person, like a good physics teacher, and not from the internet. Also, please don’t teach people. 
 

I’ll give you $500 if you can demonstrate that something with a mass of 0.3 kg has a weight of 3 kg. Same thing with the AOA meter. If it works, you get the cash. 
 

My sense is that you will not be gone long. 

17 hours ago, APenNameAndThatA said:

Okay. If you hold a spirit level at 30 degrees (same as the aircraft) and move it at 30 degrees (same as the aircraft) what does it say? 

OME?

Okay. If you hold a spirit level at 30 degrees (same as the aircraft) and move it at 30 degrees (same as the aircraft) what does it say?