Venting about flight simulators
08-02-2011, 09:38 AM
#27
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RE: Venting about flight simulators
As a plane speeds up in the air, the prop has less work to do, and is said to be "unloading", or "unloaded". Less work is required from the engine.
Once the prop hits the theoretical pitch speed, it is about as unloaded as it can get... and the plane cannot move any faster.
A higher pitch prop permits the plane to travel at a faster speed before the prop unloads fully.
However installing a higher pitch prop also has the added effects of slowing the engine down ( loading it more ) at lower speeds, resulting in less thrust produced for the same prop diameter.
Also if the prop pitch is too high, the prop can become "stalled" when the plane is moving slowly or not at all. In effect the prop spins but the plane produces little to no thrust when this happens... it also makes a lot of prop noise.
You see the results of this, as the plane appearing to be quite sluggish getting up to speed, but then picking up a lot of speed in a light dive.
It's all a balancing act where you sacrifice thrust for pitch speed, or the other way around.
On my Funtana I run a very low pitch 13x4W (?) prop. The plane flies SLOOOWLY at high throttle, but it can scoot straight up at 60% throttle without stopping.
With the ST75 I went with a balance between the two, letting the engine/prop unload in the air to get better speed via increased RPM's while maintaining decent verticals. When the plane goes vertical my prop choice let's the engine load down, but not to the point that the engine bogs down a noticiable amount.
With the ST75 my Stik will keep going straight up, but that takes almost full throttle. It hovers around 80% or so.
I'd say the plane clips along around 70 MPH or so when level at full throttle, and the AV behaviour has the flight speeds right.
What prop are you using now?
Once the prop hits the theoretical pitch speed, it is about as unloaded as it can get... and the plane cannot move any faster.
A higher pitch prop permits the plane to travel at a faster speed before the prop unloads fully.
However installing a higher pitch prop also has the added effects of slowing the engine down ( loading it more ) at lower speeds, resulting in less thrust produced for the same prop diameter.
Also if the prop pitch is too high, the prop can become "stalled" when the plane is moving slowly or not at all. In effect the prop spins but the plane produces little to no thrust when this happens... it also makes a lot of prop noise.
You see the results of this, as the plane appearing to be quite sluggish getting up to speed, but then picking up a lot of speed in a light dive.
It's all a balancing act where you sacrifice thrust for pitch speed, or the other way around.
On my Funtana I run a very low pitch 13x4W (?) prop. The plane flies SLOOOWLY at high throttle, but it can scoot straight up at 60% throttle without stopping.
With the ST75 I went with a balance between the two, letting the engine/prop unload in the air to get better speed via increased RPM's while maintaining decent verticals. When the plane goes vertical my prop choice let's the engine load down, but not to the point that the engine bogs down a noticiable amount.
With the ST75 my Stik will keep going straight up, but that takes almost full throttle. It hovers around 80% or so.
I'd say the plane clips along around 70 MPH or so when level at full throttle, and the AV behaviour has the flight speeds right.
What prop are you using now?
08-02-2011, 09:46 AM
#28
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RE: Venting about flight simulators
The OS75AX manual calls for 13 to 14 diameter sizes with different pitches.
My instructor and everyone else at the field told me 13 is too big.
I broke it in with a 13-8, but now I think I have a 12-8 on it.
My instructor and everyone else at the field told me 13 is too big.
I broke it in with a 13-8, but now I think I have a 12-8 on it.
08-02-2011, 11:09 AM
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RE: Venting about flight simulators
A 13" prop is not "too big" for that engine if you have the right pitch to go along with it...
A 13x5 may work just fine and give you tons of pull, but the plane may fly more slowly.
However I'll check to see what I'm using and let you know.
A 13x5 may work just fine and give you tons of pull, but the plane may fly more slowly.
However I'll check to see what I'm using and let you know.
08-02-2011, 12:29 PM
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RE: Venting about flight simulators
If you want realism buy MS Flight Simulator X and fly from the tower view. hahah
Seriously though, I have owned a lot of flightsims and I found that the best ones are not from RealFlight. FS One is a great one. I recall you were able to modify planes and their physics in that one. I.E. Smaller engine etc.. In that game you could even tell the torque vs. HP in 2v4 stroke engines. I feel RealFlight is targeting towards younger generations at this point: like children... They aren't going for realism anymore.
Seriously though, I have owned a lot of flightsims and I found that the best ones are not from RealFlight. FS One is a great one. I recall you were able to modify planes and their physics in that one. I.E. Smaller engine etc.. In that game you could even tell the torque vs. HP in 2v4 stroke engines. I feel RealFlight is targeting towards younger generations at this point: like children... They aren't going for realism anymore.
08-02-2011, 01:50 PM
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RE: Venting about flight simulators
I have ALL of the major sims and FS One is definitely NOT a "great one", both in terms of graphics nor in sim realism.
It sounds like you didn't really get too far into Realflight.
I had high hopes for FSOne, given that they touted fluid dynamics modeling (Ala X-Plane ). In actual practice however the models did not respond nor behave like their real life counterparts.
Of all the planes FSONE models the Alpha 40 ALMOST gets there, but in the end still falls short of real life behaviour even with a lot of adjustment of the plane.
I ( still own ) a good number of the planes in FS One ( hence my purchase ) but discovered that the physics just didn't cut it, forgetting about the abysmal graphics... though it had a wonderful initial user interface for the novice.
Of the big sims, Aerofly 5.5 and Realflight 5.5 best imitate the behaviour of real life planes with a bit of tweaking on both.
The latter does the best job, but the upgrade from Aerofly Deluxe to Aerofly 5.5 gave the sim physics approaching that of RF5.5. They are starting to "feel" quite similiar.
RF5.5 models and permits tweaking of minutae that impact the physics of the planes and helis that unfortunately AF5.5 still does not, but the latter is coming along nicely ( and it does very well on non-high end machines due to the more efficent OpenGL implementation versus DX ).
The user created planes in RF5.5 in many cases are far more accurate than the same planes in FSOne... which is why I've seeen magazine articles explaining and teaching 3D techniques with user created RF5.5 I've worked on.
Aerofly 5.5 still doesn't have airfoil stalls quite right and an improvement in that will IMHO make a big difference... ( if we could only get a better and more diverse physics editor in it too and add a bit more second order modeling...).
BTW: for some reason one thing RF5.5 does a poor job with is co-axial heli modeling, but that's a minor point.
It sounds like you didn't really get too far into Realflight.
I had high hopes for FSOne, given that they touted fluid dynamics modeling (Ala X-Plane ). In actual practice however the models did not respond nor behave like their real life counterparts.
Of all the planes FSONE models the Alpha 40 ALMOST gets there, but in the end still falls short of real life behaviour even with a lot of adjustment of the plane.
I ( still own ) a good number of the planes in FS One ( hence my purchase ) but discovered that the physics just didn't cut it, forgetting about the abysmal graphics... though it had a wonderful initial user interface for the novice.
Of the big sims, Aerofly 5.5 and Realflight 5.5 best imitate the behaviour of real life planes with a bit of tweaking on both.
The latter does the best job, but the upgrade from Aerofly Deluxe to Aerofly 5.5 gave the sim physics approaching that of RF5.5. They are starting to "feel" quite similiar.
RF5.5 models and permits tweaking of minutae that impact the physics of the planes and helis that unfortunately AF5.5 still does not, but the latter is coming along nicely ( and it does very well on non-high end machines due to the more efficent OpenGL implementation versus DX ).
The user created planes in RF5.5 in many cases are far more accurate than the same planes in FSOne... which is why I've seeen magazine articles explaining and teaching 3D techniques with user created RF5.5 I've worked on.
Aerofly 5.5 still doesn't have airfoil stalls quite right and an improvement in that will IMHO make a big difference... ( if we could only get a better and more diverse physics editor in it too and add a bit more second order modeling...).
BTW: for some reason one thing RF5.5 does a poor job with is co-axial heli modeling, but that's a minor point.
