Welcome, Guest. Please Login or Register
YaBB - Yet another Bulletin Board
  Welcome to our forum.

FFDS Home | TIPS Section | Tutorials Section | Resources Section | Utilities Section

Military | FSDS | Jetliners | Real Planes Section | Gmax | Rotorcraft | Business | Civilian

  HomeHelpSearchLoginRegister  
 
 
Page Index Toggle Pages: 1
Send Topic Print
Seaplane contact points (Read 3305 times)
13th Aug, 2010 at 5:17pm

jimslost   Offline
LDV Engineer
The more I learn, the
less I know

Posts: 337
****
 
Run for the hills, he's back ....

Here's another series of dumb questions for the brilliant minds who lurk herein.  We're building an amphibian for FSX we've encountered two problems with the contact points for the hull.  The first is that in order to get the thing to float the way we want it to, we have to place the contact points set along the waterline.  This means that the spray effects don't kick in until the hull is well into the water.  I would like to place a contact point at the first point the hull contacts the water, but if I do, my otherwise functional contact point package goes out the window.  Any suggestions?

The other problem I'm having is that once in the water, the plane takes forever to stop.  I've heard others complain about the same problem, but I've never heard anyone say how he has addressed the problem.  Has anyone fixed this problem?

BTW I tried running searches on both these issues without success.  My machine says it's looking, then says I've "timed out."  Yet another great computer mystery.

Thanks for the help,
jim
 
IP Logged
 
Reply #1 - 13th Aug, 2010 at 5:49pm

PutPut   Offline
Inspecteur des Polygonnes
I have a life; I still
use FSDS!
Long Beach, Ca.

Gender: male
Posts: 671
*****
 
Hi, Jim,  I've done a couple of sea planes for FSX (SR-45 Princess,  Curtiss SC-1) and found no simple solution to contact point placement other than trial and error.  Also, in FSX every sea plane I have has a tendency to pitch up rather violently at about 50 knots.  Haven't found a solution as of now.
  I did not have a slow down problem with the SC-1 but certainly have with the larger planes.  I gave them reverse thrust which solved the problem.

Best,  Paul
 
IP Logged
 
Reply #2 - 13th Aug, 2010 at 11:46pm

jimslost   Offline
LDV Engineer
The more I learn, the
less I know

Posts: 337
****
 
Thanks, Paul.  Wouldn't have considered reverse thrust and am not sure it's appropriate, but perhaps I can check to see how much residual thrust I'm getting at idle as a first step.  My take on the violent pitch up at 50kts is that it might be an attempt to simulate the plane "getting on the step."  I've noticed a similar motion in the opposite direction when slowing.  Would love to know what the creators of this program had in mind.

jim
 
IP Logged
 
Reply #3 - 14th Aug, 2010 at 2:11am

Au-MaV   Offline
Inspecteur des Polygonnes
Whatcha lookin at
Adelaide South Australia

Gender: male
Posts: 1956
*****
 
Hi
Not 100% sure as it was yonks since I worked on a floater but play with the scrape point give em a high crash threshold and put a couple low on the floats this will help with slowing the aircraft down and spray effects ...or was it I found that to many float points causes issues.....as I said it was a long time ago Smiley
Wozza
 
IP Logged
 
Reply #4 - 14th Aug, 2010 at 1:40pm

jimslost   Offline
LDV Engineer
The more I learn, the
less I know

Posts: 337
****
 
I tried the add'l float contact points to assist with both decelleration rates and spray effects and achieved all sorts of bizarre effects.  Haven't given up on the idea, but I was hoping someone would suggest something I hadn't though of (and really, how hard it that?).
 
IP Logged
 
Reply #5 - 21st Aug, 2010 at 12:02am

jimslost   Offline
LDV Engineer
The more I learn, the
less I know

Posts: 337
****
 
I'm still toying with the the issue of getting amphibians to slow down in a reasonable amount of time in FSX.  I am making progress.  It takes the default Goose 52 seconds to run to a stop, and the default Otter 55 seconds.  I've got my bird down to 62 - 67 seconds.  On a hunch, I tried landing the beast on a runway and letting it coast to a stop without using the brakes.  62 - 67 seconds.  A pattern?

We have an FS9 version; it stops in only 18 - 20 seconds, which is very close to real world performance.  This suggests to me that I'm dealing with an architecture problem in FSX itself.  Anyone out there know enough about the underlying architecture of FSX to comment or suggest another way to proceed (which doesn't impact other aspects of my flight dynamics structure)?

jim
 
IP Logged
 
Reply #6 - 21st Aug, 2010 at 2:49am

Au-MaV   Offline
Inspecteur des Polygonnes
Whatcha lookin at
Adelaide South Australia

Gender: male
Posts: 1956
*****
 
Hi
Hmmmm you might be generating to much thrust at min throttle in fsx,MS did play with the surface friction in fsx but which way they went I have no idea
There was quite a few changes in the FDE in fsx so your going to have different results from one sim to the other.That said there should be some middle ground
Wozza
 
IP Logged
 
Reply #7 - 21st Aug, 2010 at 1:52pm

jimslost   Offline
LDV Engineer
The more I learn, the
less I know

Posts: 337
****
 
I am continuing to investigate the residual thrust at idle power issue.  If I shutdown the engines and touchdown at 55 KIAS, the plane stops in 24 seconds.  The bulk of my flight dynamics editing and testing tools don't worth for beans in FSX, for which reason I do most of my development in FS9 and then tweek to maintain desired results in FSX.  Obviously what FS9 sees as minimal thrust, FSX sees as METO power.  Oh, well, what is life without a few challenges here and there?  (Peaceful?) 
 
IP Logged
 
Reply #8 - 21st Aug, 2010 at 3:10pm

jimslost   Offline
LDV Engineer
The more I learn, the
less I know

Posts: 337
****
 
Multimedia File Viewing and Clickable Links are available for Registered Members only!!  You need to Login or Register

Was given the above link as a starting point.  As suggested in one post, I reset my mesh resolution to 1mm and appear to have eliminated the hop, skip, and jump issue (though I'm not saying it won't return).  Of course, I have no idea what other issues this change may cause, but so far, it looks like us, one; them, nothing.
j
 
IP Logged
 
Page Index Toggle Pages: 1
Send Topic Print