The Other 3 Forces
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{ 41 comments… read them below or add one }
Another great video
Really it teaches a lot things. However still I didn’t get why winglets reduce it, I mean how does them work?
Basically there is disruption in airflow around some parts of the aircraft. The wingtips are one of these places. Basically, the higher pressure air spills over from the bottom to top, which greatly reduces lift efficiency at the tip of the wing. With winglets, this reduces that issue. (At least, this is how I understand it). People like Joe d’Eon could expound further, but that’s what I know about it.
Make sense?
thanks Chris now I got it
1.5 day to go for next video 
can’t wait it…
Winglets actually reduce wingtip vorticies, which are small circular air patterns. Vorticies act as drag on the wing and winglets reduce their size and strength.
http://en.wikipedia.org/wiki/Wingtip_device
This is very true, Ryan. These wingtip vortices do produce induced drag at the tips, however, which is partially why this wingtips are in place.
If you checkout this wiki post about a 757 retrofit, it talks about the increased efficiency with these winglets in place. Pretty cool stuff!
http://en.wikipedia.org/wiki/Boeing_757#Winglet_upgrades
Wingtip vortices cause something called ‘wake turbulence’ which varies in severity depending on the aircraft speed, size, etc. Basically, if you were to get caught in one of these things with a little cessna or other single engine, you’d probably be toast.
http://en.wikipedia.org/wiki/Wake_turbulence
There are ways to avoid it. Maybe we’ll do an episode that talks about this.
If that light reading is just too much for you to handle, just checkout this sweet pic on Airliners.net to get a feel for what these things do. It’s actually quite incredible to witness. HERE HERE
and HERE
Pretty Sweet!
Yep, the reduction in vorticies translates directly to more efficient fuel burn.
I’ve actually been right under a runway threshold before watching planes land right overhead and after the plane passes, you can actually hear the vorticies come by as they drop to the ground, it sounds like a strange fast whipping sound.
Again another great video! Thanks Chris =]
Thanks, Kace. What was your favorite part? What did you learn (if anything)?
My favorite part was about the DRAG, I did not know that they were split into four types. Induced, Form, Friction & Parasite. There you go I remembered =]
I have done a un-official PPL via some CD-ROMS which I bought a while back so I am aware of some things covered in these early videos. No doubt Im still enjoying every minute of the Aviator 90 program you put out there, It really does change the perspective you look at things the next time you fly in the simulator! Looking forward to the Control Surfaces video =]
Just to finish off, will all future videos be 5mins long? I would think that later on the Flight 1,2,3 etc may be longer? I just cant get enough of the stuff
Cheers
Kace
Hey Kace,
I want to keep these early videos as simple as possible. It’s a bit too complicated to just blow through all the PPL stuff and be unorganized about it.
Typical pilot courses will generally confuse the heck out of you. We are aiming to take a different approach and teach you with experience.
To answer your question, yes, the flights will be pretty long. Right now I don’t really want to think about how intense that part of it will be, but I’m guessing they’ll be 20 mins to 30 mins a piece (minimum). I can’t imagine we’d be able to go from here to there faster than that.
That will be where this series truly shines. Right now we are going through some of the basics that just must be taught, and then later I hope to shatter a lot of the conventional thinking about what it takes to be a pilot. That’s why we called this ‘Aviator’.
There is light at the end of the tunnel you’ve driven into Chris! Just keep grinding them out and it’ll be done before you know it, probably
Again, great video, and thank you for all the effort!
My favorite drag – induced! Thank you speed brake. I don’t know what I would do without you (other than slide right on by the field).
Bring on III
Throttle On!
alright chris, now my comment for this episode:
quick and fast, i had to watch it a couple of times, but therefore it’s a video
so to keep the drag topics apart: correct me please if i didn’t take it right or anything’s wrong
-form
is meant as a cd value? because of the example of sports car. or aerodynamic for short.
-parasite
just objects which aren’t avoidable to be placed on the aerodynamics design of the plane? such as levers, antenna, cables?
-friction
for me it’s clear, the air particles well slow it down, unless you fly in a vacuum
-induced
that’s the one i understand at least of all. i first thought it is “wanted” drag, as someone said flaps or similar around here? or do i have to understand it as a reaction of airflow get into vortices and that causes drag?
it’s not easy to get it split into 4 parts, because they’re nearly all the same.
is it important for later lessons or in general to keep this split into these parts?
after all, good job again! thx to you and your team.
regards
patrick
Hey Pat,
Let me wrap it up in as few words as possible.
Form- How the shape interacts with the air.
Parasite- Small stuff that isn’t smooth.
Friction- Air hitting the airplane.
Induced- Caused by lift in different ways (not just as the tips)
At the end of the day, drag is drag. Something that is fighting the aircraft from going forward. It’s the opposite of thrust.
If you want to keep it that simple, that’s going to be perfectly fine for now.
Excellent video Chris
Thanks, Alex. New ones coming in less than 24 hours
These are a brilliant set a videos and will be following the series closely. Many thanks.
You’re more than welcome, Anthony. We are excited to share all this stuff. The only thing we could ask for is that people love it, share it, and give us feedback so we can improve it.
Great to have you aboard! Throttle On.
Great videos! This is just what I have been looking for. Any chance of having them as a video podcast via iTunes so I can catch up on my daily commute?
I would love to do a podcast, but for now, I need to focus all my efforts on this video. I may turn my monthly messages into an audio file. We’ll see.
Sorry, what I meant was a video podcast, ie the same programmes but downloadable onto an iPod.
Sounds illegal
I don’t play on outputting those for now. I know if you go to the Vimeo and Youtube link, it has automatically made mobile versions of it that can be viewed. I’m not sure if those are downloadable or not.
Another nice video lesson Chris, and a great paint job on the 747
Thanks, Roy. Glad you enjoyed it.
Another great one! Thanks Chris
Thanks, Ted!
Hey Chris, thanks for getting back to me on those Video times & it all sounds great. Just to clear things up I did not mean to sound like I was criticizing your videos, I just meant that Ive done a PPL course nothing else. Sorry for the misunderstanding. I enjoy all AoA products!
Cant wait for the “Control Surfaces” Video tomorrow.
Just to comment, love the graphics of the Simulator , water just looks stunning! FSX rite? Are you using REX V2? My favorite part in that video was the seeing the 744 Bird in the AoA colours, great sight =]
Thanks
Kace
FSX, yes, REX v2, yes. Also, I am flying mostly in the up and coming Pacific North West scenery from ORBX (www.fullterrain.com)
It’s AWESOME!
These videos are really good! I really enjoy watching them!
First of all thank you Chris for the MASSIVE and brilliant work you are doing, absolutely fantastic way of paying back to the community. Second of all, keep on visiting FSBreak, really like your insightful opinions.
Don’t want to be a know it all (which I most certanly am not), just adding in a note here. During a constant vertical speed decent, the lift should be equal and the same as weight since the aircraft is in a constant rate of decent and not in an increasing rate of decent. Agree or disagree? (because I’m not completely sure hehe!)
Hey Emil,
I don’t think that’s the case. I still think weight is greater than lift in that case. But I’m not making any promises!
For your reading enjoyment a very easy explanation of lift by aerodynamicists, not flight instructors.
http://www.aviation-history.com/theory/lift.htm
Great videos – You’ve got a great idea here that can be used by simmers and flight students alike.
Very easy?! Haha! Looks complex to me. But thanks for the great link.
Let’s use physics correctly and not forget Newton’s law: Force = mass * acceleration
The video states (leaving AOT out of the equation for the time being) : “when lift = weight we stay in the same place, right?” (WRONG!!) and when we climb, lift is greater than weight and when we descend weight is greater than lift.
SORRY, but physics dictate: when lift = weight (there is zero net resulting vertical force) hence there is NO VERTICAL ACCELERATION: i.e. we stay at the same place (from vertical point of view) OR we move up/down at a constant vertical speed.
So the statements in the video implying that when ascending or descending (even at a constant vertical speed) , weight and lift are in balance is incorrect. When lift exceeds weight or vice versa, the plain will accelerate up (or down) i.e climbing (descending) with increasing vertical speeds..
Regards
Hey Herman,
Thanks for the comment.
I think maybe you should watch the video again. Maybe I’m reading this wrong. I clearly stated that in straight an level (and yes, I didn’t use the word unaccelerated. that is a fault) flight, weight equals lift. I also stated that when climbing or descending they weren’t equal. So, I’m not sure where we’re getting mixed up here. Thanks for the comments.
Hi Chris,
In straight and level flight lift indeed = weight. You’re absolutely right about that. Then the video continues: “when lift and weight are equal you stay in the same place, right?” Correct, but only when ‘starting from’ straight and level flight (see further on). The video then continues “When descending: weight is greater than lift” Here it goes wrong.
When descending at a constant vertical speed there is no vertical acceleration and so there can be NO resulting net vertical force: so lift must = weight. Nevertheless we are descending. So it is possible to NOT stay in the same place when lift and weight are equal. Only when accelerating down (i.e. descending at an increasing vertical speed) weight > lift. In order to leave “straight and level flight” and start to descend (negative vertical speed), weight should be > lift and thus the vertical speed (starting at zero) will decrease (i.e. become (more and more) negative) and cause the plane to descend faster and faster downwards, until weight = lift again and the plane will further descend at constant vertical speed.
In other words you need a net vertical force (lift + weight, remember they are in opposite directions) to change the vertical speed (not to continue a vertical speed)
Regards
Thanks for the great extra bit of knowledge there, Herman.
Thank You very much…
so many knowledge we can know that here….
Great to have your around!
Chris,
Great video. I love looking at the four forces of flight. When it really comes down to it the pilots job is to balance these four forces in such a way that they achieve the desired movement of the aircraft. It isn’t magic. Just killer science.