Dreamwings Q400 Assistance

Tom Clayton

Tom Clayton

Administrator
Staff member
I absolutely love the Q4, but freeware options are limited to either PAD or Dreamwings. PAD has a nice panel and VC, but external details are lacking - in my opinion... So I loaded up the DW version and found that the flight files needed a little, umm, help. The first thing I noticed was that the plane took forever to get off the ground. Then when it was airborne, it was flying close to 5° nose high despite having the elevator trim set several notches nose-down. I increased the prop thrust and cruise lift scalars by 25%, and that make things a little better, but I ended up still pitching nose up on takeoff, resulting in a high speed stall. Then I looked at the weight and balance section and noticed that both the datum and noticed that they were at model center. I looked at the plane in the preview window and noticed that the center was near the back of the wing chord. I adjusted the datum six feet forward, then pushed the lights back the same amount to keep them from floating ahead of the wingtips. The result of these tweaks is that I can now get off the ground without running through the grass at the end of a 10,000' runway, and at close to max weight, she holds about 1° nose up at 250 KIAS and 2,500' ASL (where the air is thicker) with close to neutral trim. I also increased the spoiler drag in the air file, but I haven't tested that yet.

So my question is this: Does anyone know of a revised set of air files that would better reflect how the plane should really fly? I'm guessing that there are probably some engine and geometry tweaks that could be done without having to make such drastic adjustments to the scalars, but I just don't have the skills to make those tweaks.

Edit: It looks like I'm still not getting off the ground as quick as I should. I found this page that says I should be able to get airborne in less than 5K':
http://www2.bombardier.com/q400/en/specifications.jsp
 
Which one is it, I think there is more than one. In the aircraft.cfg one is..

sim=Dash8Q400
model=WV

another is

sim=Dash8Q400
model=

at least that I know of. I don't know if the cfg's/air files are the same.
 
Assuming that CoG is correct, the first things that come to mind are CoL related:

1) Pitch affected by flaps deployment (cm_df in 1101). When flaps are deployed, it moves CoL rearward and if you have a strong pitch down moment, it will tend to keep the nose on the ground during rollout.

2) CoL is too far rearward and should be close to CoG and 25% MAC. You can try tweaking it in the cfg file with wing_pos_apex_lon= x.x. Use small increments and check CoG change with each adjustment. Or, you can add table 1534 to the air file and adjust there.

With the Dash 7, you were required to "pull" the nose off at 85-ish due to the flaps nose down effect.
 
I had the Dreamwings Q400 and found another cfg with an improved FDE. I found the original pretty poor. Couldn't get near the 360 TAS it's known for and would so strange things on takeoff etc.

The newer cfg was better and would cruise where it should. A bit of a search should find it. :encouragement:
 
Milton, after re-reading your post, I realized where you were headed. I think moving the datum forward pretty much has the pitch issue fixed. But after my research on performance, I know I'm still way under-powered. Bombardier lists the max cruise at 360 kts, but I'm not sure if that's true or indicated. But the cfg file has the max indicated set to only 265KIAS? Even if the max cruise is in TAS, I doubt the current engine configuration could come close to that at the 25,000' service ceiling.

The PAD version gets off the ground in pretty much what Bombardier says it should, so I may "borrow" some of those settings.
 
Jon_aus said:
I had the Dreamwings Q400 and found another cfg with an improved FDE. I found the original pretty poor. Couldn't get near the 360 TAS it's known for and would so strange things on takeoff etc.

The newer cfg was better and would cruise where it should. A bit of a search should find it. :encouragement:
Click to expand...

The replacement FM was done by Andrew Raney and can be found at Flightsim.com.
 
Tom Clayton said:
Thanks Milton - I bow to your superior search skills! :medals: I'll try to test the files tomorrow.
Click to expand...

I should have provided the link; sorry.

You will need to change the textures= statement or copy from your existing cfg, or rename the textures folder.
 
Well, the files from Mr. Raney didn't last very long. I turned on the lights and the strobes were floating alongside the cockpit windows. :dizzy:

So I took the Turbine Engine and Truboprop sections from PAD, tweaked those and a couple of other things, and came up with something that feels pretty good to this virtual pilot with zero time inside the real Dash 8 (other than to peek inside the cabin once when I was still working at KGSO). With 85% fuel, a full cabin load, and one notch of flaps, I get off the ground in just over half the runway at KGSO - roughly 6,000'. It's not perfect, but I like it.

I may try to get the relevant permissions to upload the changes a little later, but for now, I can only share through email.
 
You must log in or register to reply here.
Back
Top