Go Back   Knife Edge > RealFlight - Designer's Corner > RealFlight G3 - Designer's Corner
Use of this site is subject to our Terms of Use. | Looking for technical support? Read this!

Reply
 
Thread Tools Rating: Thread Rating: 13 votes, 5.00 average. Display Modes
  #1  
Old 07-05-2007, 10:49 AM
dhk79's Avatar
dhk79 dhk79 is offline
Registered User
 
Join Date: May 2006
Location: Alexandria, VA
Posts: 4,399
Physics for true-to-life performace; a Tutorial

We've had tutorials on modeling, texture mapping, importing to RF, and doing colorschemes. This one is going to focus on setting up the model's physics, such that it flies just like a real RC model would fly or "true-to-life". There are a few people who like to adjust the physics so that a biplane can do 400+ MPH. Well that is simply ludicrous, and we're not going to go there.

There is a further refinement known as "scale" performance, where the aircraft is supposed to fly exactly like a miniature version of the full sized aircraft. Some minor adjustments have to be made to achieve true "scale" performance. This is because while you can scale down the aircraft, you can't scale down the air in which the scaled plane flies. The airflow across the model's airfoils, therefore, will not separate and become delaminar at the same point along the surface. We may touch on some of these adjustments, but the primary focus will be to just get your model to correctly fly like a RC plane.

For those that would like to follow along as the steps in creating the physics model unfold, here is a freshly imported copy of the plane that we're going to work on. No changes have been made to the physics, this is how it shows up when first imported to RealFlight.
Attached Images
File Type: jpg Image1.jpg (85.2 KB, 802 views)
Attached Files
File Type: g3x Tutorial_EA.G3X (929.9 KB, 667 views)
__________________
- Knowing why ten things will not work is more important than not knowing why one does.
Doug's Project List

Last edited by dhk79; 07-05-2007 at 09:19 PM. Reason: Updated G3X file
Reply With Quote
  #2  
Old 07-05-2007, 11:10 AM
dhk79's Avatar
dhk79 dhk79 is offline
Registered User
 
Join Date: May 2006
Location: Alexandria, VA
Posts: 4,399
As you can see in the above picture, nothing in the default wire frame lines up with the 3D model. At this point you can either edit what's there or get rid of it and start over. After getting burned a couple of times by missing a setting in the default model, I usually prefer to just start over.

Get started by deleting all aircraft frame components, so that only the Airframe and battery remain (the default model is an electric).
Attached Images
File Type: jpg Image2.jpg (56.0 KB, 469 views)
__________________
- Knowing why ten things will not work is more important than not knowing why one does.
Doug's Project List
Reply With Quote
  #3  
Old 07-05-2007, 11:26 AM
dhk79's Avatar
dhk79 dhk79 is offline
Registered User
 
Join Date: May 2006
Location: Alexandria, VA
Posts: 4,399
Now open up the electronics section. Go down through the default servos and see what you want to keep.

I like to use two servos for the ailerons, as it gives better response and allows you to use differential throws (we'll discuss this later) and/or define the surfaces as flaperons. The normal servo speed for a standard servo is about .2 seconds for 60 degrees of rotation (for example a Futaba 3004 is .23 seconds), set all of the servos to an appropriate speed.

In this plane, we're not going to use a separate servo for the steering but it will have a mechanical retract servo. So rename the steering servo to a retract servo and change its speed to .58 (Futaba S136G).
Attached Images
File Type: jpg Image4.jpg (74.1 KB, 344 views)
__________________
- Knowing why ten things will not work is more important than not knowing why one does.
Doug's Project List
Reply With Quote
  #4  
Old 07-05-2007, 11:35 AM
dhk79's Avatar
dhk79 dhk79 is offline
Registered User
 
Join Date: May 2006
Location: Alexandria, VA
Posts: 4,399
Lastly open the Software Radio section. We're going to use channels 1 & 5 for the ailerons. As a starting point for the ailerons change the channel settings for 1 & 5 to:
Low Rates - 50%,
Expo During Low Rates - 30%,
Expo During High Rates - 60%.
Attached Images
File Type: jpg Image5.jpg (88.3 KB, 242 views)
__________________
- Knowing why ten things will not work is more important than not knowing why one does.
Doug's Project List
Reply With Quote
  #5  
Old 07-05-2007, 11:46 AM
dhk79's Avatar
dhk79 dhk79 is offline
Registered User
 
Join Date: May 2006
Location: Alexandria, VA
Posts: 4,399
Also under channels 1 & 5 there are some other factors that may need adjustment.
In the category Low Rates When, change the Activated When to "Conditional Channel below or equal to value #1". The Conditional Channel should be Channel 5 - Dual Rates. This sets your low rates to the forward position of the dual rate switch. Note: This is a personal preference, as I like to have my real radio setup with a default take-off configuration that has all switches in the forward position. One glance and I know my radio is configured properly for take-off.
Exponential when should be set to Activated Always.
No changes are needed to the input as it is set to Channel 1 - Roll and is active always.
Attached Images
File Type: jpg Image6.jpg (62.7 KB, 271 views)
File Type: jpg Image7.jpg (50.2 KB, 189 views)
File Type: jpg Image8.jpg (51.0 KB, 164 views)
__________________
- Knowing why ten things will not work is more important than not knowing why one does.
Doug's Project List

Last edited by dhk79; 07-05-2007 at 11:51 AM.
Reply With Quote
  #6  
Old 07-05-2007, 12:03 PM
dhk79's Avatar
dhk79 dhk79 is offline
Registered User
 
Join Date: May 2006
Location: Alexandria, VA
Posts: 4,399
Output Channel 2 should be set up the exact same way as Channels 1 & 5, with the exception that Input should be Channel 2 - Pitch.

Output Channel 3 will be a little different. You probably do not want to have either dual rates or exponential throws on the throttle. The settings are therefore:
Low Rates - 100%
Expo During Low Rates - 0%
Expo During High Rates - 0%
Low Rates When - Always
Exponential When - Never
Input - Channel 3 - Throttle
Input When - Always
Attached Images
File Type: jpg Image9.jpg (48.6 KB, 130 views)
File Type: jpg Image10.jpg (48.8 KB, 101 views)
File Type: jpg Image11.jpg (49.3 KB, 100 views)
File Type: jpg Image12.jpg (49.9 KB, 101 views)
__________________
- Knowing why ten things will not work is more important than not knowing why one does.
Doug's Project List
Reply With Quote
  #7  
Old 11-17-2016, 02:59 PM
badbob badbob is offline
Registered User
 
Join Date: Sep 2012
Posts: 12
Quote:
Originally Posted by dhk79 View Post
We've had tutorials on modeling, texture mapping, importing to RF, and doing colorschemes. This one is going to focus on setting up the model's physics, such that it flies just like a real RC model would fly or "true-to-life". There are a few people who like to adjust the physics so that a biplane can do 400+ MPH. Well that is simply ludicrous, and we're not going to go there.

There is a further refinement known as "scale" performance, where the aircraft is supposed to fly exactly like a miniature version of the full sized aircraft. Some minor adjustments have to be made to achieve true "scale" performance. This is because while you can scale down the aircraft, you can't scale down the air in which the scaled plane flies. The airflow across the model's airfoils, therefore, will not separate and become delaminar at the same point along the surface. We may touch on some of these adjustments, but the primary focus will be to just get your model to correctly fly like a RC plane.

For those that would like to follow along as the steps in creating the physics model unfold, here is a freshly imported copy of the plane that we're going to work on. No changes have been made to the physics, this is how it shows up when first imported to RealFlight.
Can't open the Tutorial_EA.3GX file.
Reply With Quote
  #8  
Old 11-17-2016, 06:17 PM
adrenoline 60 adrenoline 60 is offline
Registered User
 
Join Date: Jan 2014
Location: Wisconsin
Posts: 643
Quote:
Originally Posted by badbob View Post
Can't open the Tutorial_EA.3GX file.
This is an airplane file. It opens just like a Swap Page File.
http://www.knifeedge.com/forums/impo...importhelp.php
Are you asking for G3 or RF 7.5 ?
Please Check your Private Messages

Last edited by adrenoline 60; 11-17-2016 at 06:30 PM.
Reply With Quote
  #9  
Old 02-01-2017, 12:03 AM
roseawebs roseawebs is offline
Registered User
 
Join Date: Jan 2017
Posts: 1
Quote:
We've had tutorials on modeling, texture mapping, importing to RF, and doing colorschemes. This one is going to focus on setting up the model's physics, such that it flies just like a real RC model would fly or "true-to-life". best tactical reviews There are a few people who like to adjust the physics so that a biplane can do 400+ MPH. Well that is simply ludicrous, and we're not going to go there.

There is a further refinement known as "scale" high performing light , where the aircraft is supposed to fly exactly like a miniature version of the full sized aircraft. Some minor adjustments have to be made to achieve true "scale" performance. This is because while you can scale down the aircraft, you can't scale down the air in which the scaled plane flies. The airflow across the model's airfoils, therefore, will not separate and become delaminar at the same point along the surface. We may touch on some of these adjustments, but the primary best folding knife focus will be to just get your model to correctly fly like a RC plane.

For those that would like to follow along as the steps in creating the physics model unfold, here is a freshly imported copy of the plane that we're going to work on. No changes have been made to the physics, this is how it shows up when first imported to Real light.
I just signup here to say you thank you. Just awesome information you have added in this thread. Actually, I was looking for clear physic explaination.

Last edited by roseawebs; 04-18-2017 at 08:08 AM.
Reply With Quote
  #10  
Old 02-01-2017, 05:48 PM
brields's Avatar
brields brields is offline
Registered User
 
Join Date: Aug 2011
Posts: 1,039
If you really want true to life performace, there are three things you need to know about your plane.

center of gravity,
lift to weight,
Thrust to weight.
__________________
Only The best wear red
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:33 PM.