The blades twist there angle to change the thrust. They don't stop and go the other direction like a box fan does.

That wasn't the point of my comment. What's with the penchant to overlook the obvious intent, is it simply in order to "find some fault" with an analogy? :( Or, just in case the obvious intent wasn't -well- obvious, the point being made is that of being a "push versus a pull" with regards to airflow.BTW, there's a very distinct difference in meaning between "there" and "their..." :(

You are the troublemakler and you started picking nits with my explanation above. And I agree your example is plain wrong for the reasons stated.

And another thread turns into a pi**ing contest. :(

Thank you Captain Obvious... :( That wasn't the point of my comment. What's with the penchant to overlook the obvious intent, is it simply in order to "find some fault" with an analogy? :( Or, just in case the obvious intent wasn't -well- obvious, the point being made is that of being a "push versus a pull" with regards to airflow.BTW, there's a very distinct difference in meaning between "there" and "their..." :(

It may be obvious to you but it might not be obvious to who this subject is directed to. He is having a hard time conceptually visualizing what is happening with the props. That is why I gave him a diagram which shows blade angle. You never want to put the wrong idea in someones head in fear of primacy taking over. If you teach them the wrong concepts first then they are more likely to go back to that wrong idea instead of the correct one someone is trying to teach them.So, no the blades don't reverse their direction like you wrongly suggested in a false analogy. They instead continue in the same direction of travel as forward thrust but twist their angle until they produce a thrust in the forward direction.You have a very funny attitude about someone trying to convey the correct information.

So, no the blades don't reverse their direction like you wrongly suggested in a false analogy. They instead continue in the same direction of travel as forward thrust but twist their angle until they produce a thrust in the forward direction.You have a very funny attitude about someone trying to convey the correct information.

I have no problem at all with any attempt to "convey the correct information." I was however trying to present an alternate and somewhat simpler example of the effect of blade angle reversal.Nothing I wrote in any way denigrated nor even implied that your technical explanation was somehow faulty or inaccurate.Let's revisit my simple analogy once more with a slightly different twist (pun intended!):

Take the blades off the box fan and reverse them when reinstalling. Blade pitch is now reversed.Turn fan on. Airflow is in the opposite direction now, yes?The end effect is the same either way...

@jahman: my comment was not directed to your post, but rather was addressed to the topic as a whole. There's no point in explaining the principles of nuclear engineering when someone asks how to start a campfire.

@jahmanThere's no point in explaining the principles of nuclear engineering when someone asks how to start a campfire.

Exactly!!! :(

I have no problem at all with any attempt to "convey the correct information." I was however trying to present an alternate and somewhat simpler example of the effect of blade angle reversal.Nothing I wrote in any way denigrated nor even implied that your technical explanation was somehow faulty or inaccurate.Let's revisit my simple analogy once more with a slightly different twist (pun intended!):@jahman: my comment was not directed to your post, but rather was addressed to the topic as a whole. There's no point in explaining the principles of nuclear engineering when someone asks how to start a campfire.

Wrong or not, I'd say it was a little sarcastic or overly simplistic. Wouldn't you? You were corrected (politely I might add) and you over reacted. It happens! Let's move on. These post are taking away from the OP.Also. If one wants to offer elementary explanations of things, that's fine. If another wants to give accurate, more in depth explanations, that's okay too. This isn't fission, by the way. :(

So is a reversed propeller simply "upside-down" as in a car spoiler? As in, does the wing "turn upside down" when looking at the airfoil from the side? http://www.centennialofflight.gov/essay/Evolution_of_Technology/props/Tech14G1.htmOr does the propellor in reverse pitch simply look like the mirror image of this cross-section?So is a reversed propeller simply "upside-down" as in a car spoiler? As in, does the wing "turn upside down" when looking at the airfoil from the side? http://www.centennialofflight.gov/essay/Evolution_of_Technology/props/Tech14G1.htmOr does the propellor in reverse pitch simply look like the mirror image of this cross-section?

So is a reversed propeller simply "upside-down" as in a car spoiler? As in, does the wing "turn upside down" when looking at the airfoil from the side? http://www.centennialofflight.gov/essay/Evolution_of_Technology/props/Tech14G1.htmOr does the propellor in reverse pitch simply look like the mirror image of this cross-section?

The airfoil basically turns it's self "upside down" relative to the wind. It's angle of attack basically does opposite what it usually is. The angle goes negative. I don't know how else to word it, sorry! It's easier if I could just show you with my hands!

Hi.A quick search turned this picture up:It came from about half way down this page:http://airplanegroundschools.com/Transition-to-Turbopropeller-Powered-Airplanes/The picture is in two halves. On the left, various engine/prop control settings. On the right a view of the propeller disc & nose cone from above/side (only one blade showing, and that in cross section). The prop disc spins over and down the page, the plane moves from left to right of the page. You can see that with forward thrust the prop blade will effective take a bite of the air & throw it to the left of the page. With reverse pitch the prop has swivelled and takes a bite and throws it to the right of the page, blowing the plane backwards.Maybe that helps. I can see a lot of confusion being caused by words like 'turn' and 'rotate' when turning and rotating are happening is several directions at once...Regards,D

means exactly what ?

Shouldn't have to explain that one.Anyway. That's the picture I was looking for, Dave. Nice find.

Shouldn't have to explain that one.Anyway. That's the picture I was looking for, Dave. Nice find.

You're welcome.The page has been a big help to me as I've just moved up to Flight1's C441 as my first twin, and while some of the control is overlooked in their model it's nice to have a good explanation of the effect different control positions should have.Regards,D

Hi.A quick search turned this picture up:It came from about half way down this page:http://airplanegroundschools.com/Transition-to-Turbopropeller-Powered-Airplanes/The picture is in two halves. On the left, various engine/prop control settings. On the right a view of the propeller disc & nose cone from above/side (only one blade showing, and that in cross section). The prop disc spins over and down the page, the plane moves from left to right of the page. You can see that with forward thrust the prop blade will effective take a bite of the air & throw it to the left of the page. With reverse pitch the prop has swivelled and takes a bite and throws it to the right of the page, blowing the plane backwards.Maybe that helps. I can see a lot of confusion being caused by words like 'turn' and 'rotate' when turning and rotating are happening is several directions at once...Regards,D

That's the clearest I've ever seen prop pitch illustrated. Thanks a lot! :( That helped a lot. By the way, what do the condition levers do? Do they vary the fuel mixture (like the mixture levers in a piston-engined aircraft)?

Have you tried typing "condition lever" in Google? I'm sure there's a lot of results.

The condition lever is more of an on and off switch for fuel. I fly a King Air 200 with PT6 engines. Our throttle quadrant looks much like that picture posted (except for a second set of each of those levers for the second engine.) Here is how we use those levers:

1. We energize the starter to turn the turbine and light up the igniters.
2. Once the the turbine is stabilized around 12% we move the condition lever to low idle.
3. Watch the turbine start. Temperature not over 920° C. and turbine should be over 30%
4. Once the turbine is stabilized at around 45% then we move the condition lever up to high idle. This causes the turbine to run about 5% faster. The only reason we do this is so that the generator is turning faster to provide more power in charging the battery so we can start the second engine.
5. Start the second engine the same way as above.
6. Once both engines are stabilized we turn on both generators and then bring the condition levers back to low idle and leave them there until we are done with the flight and shut down the engines.

The only time you may need to use high idle for flight is operating from a hot and high airport where you need more power to generate full torque.Other engines operate a little differently where the condition lever is positioned in a ground position which turns slower so you can taxi or a flight position for the rest of the operations.