Aircraft in aces high II

[Bronk]

Yes, but the prop is just a tool utilized by the engine.

Stop digging.

[Masherbrum]

Yes, but the prop is just a tool utilized by the engine.

....and you're nothing more than a squeaker with a troll's figure.   If you cannot understand my simple Physics lesson and HT's addendum, then take a Physics class.   

[Wmaker]

This thread make me think of something: The F16 is unique as, if I'm understanding correctly, it's thrust at burner actually eXCEEDS the weight of the jet? So...it can accelerate going straight up. What propeller-driven craft has come closest to that?

The F-16 isn't unique in that regard, btw.

Anyways, when talking about fixed wing prop driven aircraft...two quickly come to mind; Turbine Toucan and Turbo Raven. Both are (were in the case of the Raven) one off jobs. Well, Turbine Toucan is basically modified Pitts Model 12 with turboprop powerplant.

They are promising close to 1.65:1 thrust to weight ratio in airshow weight.

http://www.turbinetoucan.com/homepage/

Pretty hilarious ride I'm sure.

[Nemisis]

See Rule #4

[dtango]

wow, I wasn't disagreeing that thrust is produced by the prop. I was simply saying that if you want more thrust, you must make the prop spin faster (assuming a fixed pitch prop), and that would be done by the engine.

You do realize that spinning the prop faster might actually produce less thrust right?  This is especially true for a fixed pitch prop.

Tango
412th FS Braunco Mustangs

[Nemisis]

Thats true... once it reaches a certian speed (not sure of what speed though). But I guarantee that a prop spinning at 100rpms will generate more thrust than one spinning at 50rpms. I know physics (sort of), but I have a terrible head for numbers.

[dtango]

Thats true... once it reaches a certian speed (not sure of what speed though). But I guarantee that a prop spinning at 100rpms will generate more thrust than one spinning at 50rpms.

Not necessarily.  It's all about the blade relative angle of attack which is greatly influenced by the vector sum of forward airspeed and prop rotational speed.  This is often represented by propeller advance ratio:

J= V/n*d

Where V = airspeed, n= prop rotation, d= prop diameter

Advance ratio is usually plotted against propeller efficiency like this:



For a fixed pitch propeller there's a maximum efficiency that is attained by a combination of V/n*d.  You adjust this for airplanes with fixed pitch props in flight two ways, either by airspeed or by rpm's.  It's a balancing act of velocity and rpm where raising or lower rpm is needed to maintain max efficiency thus max thrust.  Higher RPM does not = higher thrust automatically.

Tango
412th FS Braunco Mustangs

[Mongoose]

Yes, but the prop is just a tool utilized by the engine.

The prop is there to keep the pilot cool.  If you don't think so, make it stop turning, and watch him sweat! 

[Nemisis]

hmmm... point taken. Still, there is a limit to how much altering the pitch of the blade will do. Eventually you will have to make it spin faster, or cram more engines onto your aircraft. Props to have limits, which is why we have jets.

[Rino]

     Props tend to get longer and have more blades to handle more power. 

[Masherbrum]

wow, I wasn't disagreeing that thrust is produced by the prop. I was simply saying that if you want more thrust, you must make the prop spin faster (assuming a fixed pitch prop), and that would be done by the engine.


Are you pissed because your wife kicked you out?

My wife and I are happily married.   So what does my marital status have to do with the fact that you have no clue about Physics?   Your statement on the engine is STILL incorrect. 

Your arms look tired, put the shovel down and listen (read). 

[hitech]

dtango, your mixing efficiency with thrust.

Eff = (Thrust * Speed) / Power

Nemisis statement of more rpm = more thrust is almost always correct unless a prop has a very large blade angle of 30 degrees or more and traveling at very slow speeds.

HiTech

[dtango]

dtango, your mixing efficiency with thrust.

Eff = (Thrust * Speed) / Power

Yes, but thrust = power * eff / speed no?  Thus the amount of thrust is also a function of prop efficiency which depends on rotational velocity as a component.
  

Nemisis statement of more rpm = more thrust is almost always correct unless a prop has a very large blade angle of 30 degrees or more and traveling at very slow speeds.

HiTech

Agreed.  Perhaps I'm being too pedantic on my part in responding to Nemisis . Point taken.

Tango
412th FS Braunco Mustangs

[hitech]

Yes, but thrust = power * eff / speed no?  Thus the amount of thrust is also a function of prop efficiency which depends on rotational velocity as a component.

Try using this equation standing still.

HiTech

[dtango]

Try using this equation standing still.

HiTech

Thanks for throwing in a monkey wrench and pointing out the static thrust case to mess me up, but you're right and have made your point!

Tango
412th FS Braunco Mustangs