[SOLVED] Anyone else get stuck on the ground?

[carthorse]

I have been experiencing a strange behavior where the DC-3 gets hung up on the surface. When this happens it takes 100% power to get it moving. It seems to consistently occurr when you are off of a paved surface. But occasionally when on pavement, it is very difficult to move...or it decelerates very quickly and noses over on landing.

Anyone else experience this?

[RojanTrojan]

I have been experiencing a strange behavior where the DC-3 gets hung up on the surface. When this happens it takes 100% power to get it moving. It seems to consistently occurr when you are off of a paved surface. But occasionally when on pavement, it is very difficult to move...or it decelerates very quickly and noses over on landing.

Anyone else experience this?

Hi, yes I too get this from time to time, when i try to taxi on some grass. I assume it maybe the way that x-plane models these sort of areas off paved taxiways? I'm not sure. But I have to use 100% to get going like Carthorse has explained.

Cheers

Rhydian

[carthorse]

I have found that two things play a part in this issue:

1. Flaps

2. gross weight

The flaps in this model create a tremendous amount of drag. In fact, when loaded to 25,000lbs or so, i can't even maintain enough airspeed to make the runway at full flaps on a 3 degree glideslope. I have to either apply flaps short final or not at all -- this isn't quite realistic. So when on the ground and you are stuck...raising the flaps actually helps 'unstick' the aircraft and get it rolling -- the reduction is drag helps.

2. the weight of the aircraft has a large effect whether or not i get stuck on the runway. I fly with FSEconomy.com which loads the aircraft for me. I've flown in many different configs from empty to 28,000lbs (military's gross weight allowance). The lighter I am, the easier it is to get rolling -- the heavier, the easier it is to get stuck.

Sometimes just one wheel gets stuck. Sometimes both.

[Goran_M]

This was an issue I was faced with in testing. The DC-3 in X plane moves far too quickly with the default friction co-efficient. Meaning that the take off and landing run was too short. This had to be adjusted to get the correct takeoff and landing run. IIRC, X Planes ground modelling on non-paved surfaces has been an issue with other aircraft as well. The friction co-efficient can be turned down, but then take offs and landings would be shorter. How short depends on the reduction of friction.

I'll have a look at this some more and see what I can do with it.

[carthorse]

Thanks for the explanation, that makes sense to me too.

If it helps any, when i flew on a DC-3 i took note of some of the performance numbers:

Aircraft config

• Full Main tanks + 100gal in each aux tank.
  
• 6000lbs of cargo
  
• 1200hp twin wasp engines
  

Climb

• Power: 35" manifold, 2300rpm
  
• Speed: 115 kts
  
• Rate of Climb: 400fpm
  

Takeoff

• Power: 41" manifold - full RPM (36" used on longer runways)
  
• Distance: 1500 ft (we actually had 8000lbs payload for this takeoff)
  
• Surface: compact dirt
  

Cruise

• Power: 30" manifold - 2200 RPM
  
• Altitude: approx 8,000 ft
  
• Speed: 125 kts TAS
  

[eaglewing7]

Hate to bring up an older thread, but I've recently begun running into the same issue as carthorse.

 

Using X-Economy (or FSEconomy), I've been flying from CYEV (paved runway) to CYOC and CZFM (both unpaved).  At both CYOC and CZFM, I have a heck of a time getting the plane airborne, and fro time to time have to use the local map and bump the airplane 50 feet off the ground at about 70 knots just to get into the air.  Landing is interesting as well, as the plane will just stop dead on the runway with no braking whatsoever...

 

Since you said this was being looked into, I can assume that when the post SAAB release patch for the DC-3 is released, it will hopefully be corrected, or adjusted?

[carthorse]

Hi Eaglewing,

I pretty much just don't use flaps.

1.  with flaps down, there is so much drag you can hardly maintain approach speed with tons of power

2.  with flaps down, it takes much more power to taxi

3.  with a load in the plane, it is almost impossible to taxi on a non-paved strip (especially with flaps down).

Another thing you can do is takeoff with minimum weight...then start your flight once airborn.

But landing is embarassing on vatsim due to this issue.

[Goran_M]

I will have a look at this and maybe reduce the ground friction.  Keep in mind, the ground modelling in X-Plane MIGHT be somewhat suspect.  I'm not pointing any fingers, but it seems the gravel or dirt runways restrict take off speed a lot more than it should be.  

I'll see if I can find some kind of compromise between hard surface and soft surface runways. 

The one major problem is, if I reduce ground friction, the DC-3 is almost impossible to stop on hard surface runways.

Edited June 16, 2013 by Goran_M

[eaglewing7]

I have noticed that when you use more than half flaps, you certainly need a lot of power to just maintain your approach speed.  After doing my real world multi-engine rating, I certainly don't want to have my airspeed decay below red line on the approach, but often times even at 30+ inches of mercury, it will barely hold 80 or so knots...

 

Interestingly enough, on unpaved strips, I've noticed that the DC-3 really likes to pitch forward onto the main gear at higher power settings, so you can taxi around at really low speeds "two point".

 

Something in the ground handling even seems a bit suspect sometimes on paved strips, where you need a lot of power to get moving, and then have to maintain something like 25" Hg to taxi at a constant speed.  It could be that increasing the ground friction has caused other performance related errors down the line.

 

I think I'll do some testing later today with different friction settings on paved, and then later unpaved runways, and see what happens to the performance numbers.

 

Edit: As for a compromise between paved and unpaved, maybe coding something that would differentiate between the runway surface, and then either reduce or increase the friction as necessary, if that is even possible...

Edited June 16, 2013 by eaglewing7

[carthorse]

Thanks for looking at this Goran.

Eagle: i've also noticed that you can lift the tail as if it were a cub.  I flew on a DC-3 for a day once and i have to say there is no way you could lift the tail below 60kts.  Also, when landing as the tail comes down, it's almost impossible to break so hard that you tip over on your nose.

Also Typical approaches were made with 21" manifold 2000rpm easily maintaining about 80 to 90 kts with full flaps and gear down.

Hope any of this helps, i don't expect the DC-3 to be exactly like the real thing.  It's a pleasure to fly as it is, but the ground handling is pretty bad when you can't taxi at all on rough surfaces.

Thanks!

[BWolf7]

Same thing happening to me.

[eaglewing7]

Eagle: i've also noticed that you can lift the tail as if it were a cub.  I flew on a DC-3 for a day once and i have to say there is no way you could lift the tail below 60kts.  Also, when landing as the tail comes down, it's almost impossible to break so hard that you tip over on your nose.

Also Typical approaches were made with 21" manifold 2000rpm easily maintaining about 80 to 90 kts with full flaps and gear down.

Hope any of this helps, i don't expect the DC-3 to be exactly like the real thing.  It's a pleasure to fly as it is, but the ground handling is pretty bad when you can't taxi at all on rough surfaces.

 

 

 

Certainly correct, no reason you should have anywhere near cruise power on during a descent to land, unless you've really let your speed decay...

 

I've got a good thirty hours of real world taildragger time, all of it in 7ECA Citabria's, and you certainly cannot lift the tail at low speeds, generally you get the tail up at 40 mph, and then lift off at 60 mph...  Totally different aircraft though.

[trevg]

Old one but still have this problem.

It was going to be looked at, is it in the too hard basket  ??

 

Hoping on small reduction in grass friction in the update.

 

Having great fun with this aircraft, low and slow and with the new mesh, wow.

 

Cheers

[Goran_M]

It's a very difficult one to "fix".  I have it running on paved surfaces, pretty much, perfectly.  Gravel and grass is tricky.  I CAN make it a bit slicker, but then it would skid all over a wet surface.  

When i originally made the flight model, I made it for wet and dry paved surfaces, because there are many more of them than there are dirt and grass surfaces.  I can TRY to tweak it a bit more, but I'm not sure it would be possible without affecting its performance on paved surfaces.

[iandiss]

Have the same problem.

 

I changed the landing gear coefficients using plane maker/Standard/Landing Gear/Gear Data/Landing Gear Friction coefficients to 0.025 and 0.750 and this works perfectly for me.

It still takes a bit of power to get moving, but by using throttle, brakes and rudder pedals it is OK and I can reduce power once the aircraft moves. I have no problems with the new settings on paved aprons and runways.

I know playing with settings is frowned upon but as I do most of my flying in and out of grass and gravel strips in the Yukon and Alaska it makes a brilliant but unusable aircraft one of my favorites.

 

Hope this may be of some help.

[iandiss]

Hi Goran,

 

You got your post in while I was typing mine. I don't know if you want to look at the settings I am using but as I said they work for my type of flying.

 

Regards

[trevg]

Thanks Goran for your reply.

I would rather have a fix from you than try to fix with above, having no knowledge of plane maker

Yes I do tend to use the old DC 3 with old strips (normally Grass) 

Regards

[strobe1978]

Have been dealing with this issue for awhile too. One tire off the asphalt and I'm toast. Not feeling any toe breaks on ch peddles. Maybe if I figure that out, I could stay on the asphalt-heh-heh...

[Goran_M]

I'm running a few tests today and would like some feedback for a fix.

Is the problem with BOTH variants or just one?

[trevg]

I have only used the wheel version 64 bit.

I actually did the alteration in plane maker in post further up and it worked ok for me both on grass and seal.

Maybe not the best solution but at least I can get across the grass now. 

[Vinny003]

Hi, guys!

I'm using the dc-3 v1.4, my dc-3 won't move on the ground off the taxiway/runway at 23,328 pounds at throttle settings just enough to get the plane moving on the taxiway/runway. Thanks!

Cheers,

Vincent

[Goran_M]

Add more power.