Fight Cub... DTG versus DTG

[Chock 17,769]

Not exactly scientific, but interesting all the same. Here's the default FSW Piper Cub on a quick circuit at LFPG with fair weather, followed by the default FSX-SE Piper Cub on a quick circuit at LFPG also with default fair weather. So it's a reasonably close comparison since both sims have been tweaked settings-wise to get about 30 fps in the VC and about 50 fps on external views in flight with things dropping to about 15-20 fps at busy payware airports in FSX-SE.

I put the FPS counter up on screen for both sims although you should be aware that FRAPs tends to impact the frame rate a bit and make things a bit jerky in both sims when it streams a full screen recording at high fps, so I wouldn't really regard the video as an accurate reflection of typical FPS or smoothness for either sim when not recording a video, since both are actually smooth on that PC on these particular settings.

For reference, the PC I did this on is not a particularly fancy one, it has: Intel i7 2600 at 1596 Mhz, 8Gb DDR 3 at 667 DRAM frequency and an AMD Radeon HD 6900 with 2Gb of RAM at 500Mhz, although some of that is a bit souped up with Catalyst, for example the overdrive settings and GPU speed, though not much, so it's a well below spec PC for a modern flight sim, but still able to be flyable with things such as the FSL A320 and the PMDG 747-400 when running other stuff like Pro ATC, Active Sky etc.

It's apparent to me when doing this comparison, that the FSW Cub is prettier with better modeling and textures and has a better VC, and although Accufeel is installed in my FSX-SE, as it is by default in FSW, I feel the FSW Cub flies a tiny bit better than the FSX-SE one does. The terrain is sort of similar in both although I think the FSW stuff just kind of edges it in looks at least in my preference. The draw distance is greater in FSX-SE although to be honest, since I am unable to spot trees 14 miles away in real life, I ain't too bothered about not being able to do so in a sim, so I'm personally fine with FSW'S LOD range. Having seen the comparison, I can kind of understand why DTG has gone for a lighter look to the terrain as the airport does seem to blend into the surrounding terrain a bit better and the runways look a bit less '1998 flight sim' to me.

But as ever, you might disagree with me.

 

 

 

 

 

[Alphafoxsierra 166]

An interesting comparison - thanks for sharing!

[Oracle427 45]

Chock,

If the FSW Cub feels better it's because it is a completely different aircraft. The Super Cub has nearly double the horsepower, but doesn't weigh twice as much. It should feel a lot more, well, Super! :)

The Super Cub is also flown from the front seat whereas the J-3 is from the back seat. The seats are higher in the PA-18 so the forward visibility is excellent.

Edited June 1, 2017 by Oracle427
Added comments on visibility.

[Chock 17,769]

Yeah that's true, but aerodynamically all Cub variants are broadly very similar, and it was less about the power that made me feel it was flying better, more about the way it generally handled, for example when the power was off, or cut back in the turn for final and in the flare, which of course would mean the amount of pull one was getting would be more to do with gravity than horsepower. There is just something about FSW which makes me think GA  aircraft fly a bit better in it.

[Oracle427 45]

They are aerodynamically similar, yes, and the extra power unfortunately isn't enough to overcome the parasite drag of the similar airframes. As a result the cruising speed of the PA-18 isn't that much higher.

The control response of a PA-18 is much better than that of a J-3. The controls in a J-3 feel sluggish and introduce a lot of adverse yaw in turns. If you don't use the rudder and roll into a 30 degree bank, you can count to 3 or 4 before the nose begins to yaw past the point of reference before the roll was initiated. The PA-18 doesn't exhibit quite as much adverse yaw and will generally yaw within 1-2 seconds. The difference is very noticeable and great for teaching good technique in the J-3. The PA-18 lets you get away with murder if you are sloppy when compared to the J-3.

I've never compared the surface area of the tail on the two, but if memory serves right, the PA-18 has larger stabilizers.

The J-3 climbs, descends in a rather level attitude, there isn't too much power to play with so the difference between cruise and climb is just a couple of degrees. On a PA-18, you can easily climb at a steep deck angle, so in all it feels more dynamic.

I also forgot that the PA-18 has flaps and that makes a big difference for takeoff and landing performance. The approach speeds are fairly similar at around 50 MPH-55MPH for both airplanes (PA-18 with full flaps). Both planes initially climb at about the same airspeed, but the PA-18 will climb much more steeply with the extra power.

In fact, if you have flown a C172 with an O-320 and then flown the same aircraft with an O-360, it feels like a different airplane despite being the exact same airframe. In my case, it was the same serial number.

The Super Cub is one of my favorite planes to fly IRL. I'll be buying a copy of FSW soon to try it out once I get a little more free time.

Lastly, I do wonder if the flight modelling is generally improved in FSW. It would be nice to discover this as I've seen a few comments suggesting that this may be the case.

Edited June 1, 2017 by Oracle427
FM and C172 comments added.

[Griphos 138]

I haven't really had enough time to say that it has.  And the little time I had was in the prior version from DTG.  But I have FSW installed, so will do a bit of testing.

By the way, didn't the J-3 and PA-18 both use the 35B airfoil?  They may have been attached at different angles of incidence (I don't know) but I suspect it's the different tailfeathers that makes most of the difference in flight handling.  And there is indeed a real difference.  

[carbonbasedlifeform 179]

3 hours ago, Oracle427 said:

The control response of a PA-18 is much better than that of a J-3. The controls in a J-3 feel sluggish and introduce a lot of adverse yaw in turns. If you don't use the rudder and roll into a 30 degree bank, you can count to 3 or 4 before the nose begins to yaw past the point of reference before the roll was initiated. The PA-18 doesn't exhibit quite as much adverse yaw and will generally yaw within 1-2 seconds. The difference is very noticeable and great for teaching good technique in the J-3. The PA-18 lets you get away with murder if you are sloppy when compared to the J-3.

 

So is the proper way to turn the J3 the same as other planes just less forgiving? Or does it need to be turned differently?

[Griphos 138]

Proper (coordinated turning) is proper for all aircraft.  It's just that some aircraft, particularly older aircraft with more "aesthetically" rather than "aerodynamically" designed tailfeathers often require more rudder input to stay coordinated.

That's what Oracle was saying.  Aileron input alone on a Cub points your nose rather quickly in the opposite direction from the turn you initiated.  And it takes a while to wallow back in the direction you want, which means the plane is banked, but not really turning yet, but rather skidding forward still.  

Basically you want to input rudder at the same time you move the ailerons to compensate for adverse yaw and get the plane turning.  Once in the turn you can basically neutralize both stick and rudder, and then, when you want to exit the turn, you use matched inputs again.  

How much rudder to use is different for every airplane, and different at different speeds (as is how much aileron is required to roll).  Some require very little rudder to coordinate a turn (overcome adverse yaw), because they have wings with chords or ailerons designed to help.

If you're not familiar with adverse yaw, it is yaw induced because of several factors that work together to push the plane in the opposite direction from the turn: 

1) The wing that rises from aileron input changes its chord and produces more lift because a higher angle of attack to the relative wind, and the wing that dips produces less lift relative to the other wing since it's chord and AOA is reduced.  This pushes against the desired direction of turn. 

2) The wing that rises has a bit more induced drag as well, pulling the plane in that direction (against the turn).  

3) But perhaps the biggest factor is the change in the lift vectors around the pitch axis since the wings are producing lift differently in relation to the original direction of travel.  The lift vector of the raised wing tilts backward (because higher AOA) and the lift vector of the lower wing tilts forward, again pushing the nose in the opposite direction from the turn desired.  

One of, if not the best books on flying is one of the oldest and, in many ways, easiest to understand.  If you haven't ever read it, get a copy of Stick and Rudder.  

[Oracle427 45]

5 hours ago, Griphos said:

One of, if not the best books on flying is one of the oldest and, in many ways, easiest to understand.  If you haven't ever read it, get a copy of Stick and Rudder.  

+1 to this recommendation and all of the above.

In in (weak) effort to go back on track. Nice video for the comparison and I agree with Chock's observations on visuals. :)

[jcomm 5,939]

In FSW - I don't recall exactly how it was with the Cub in FSX:SE - there is way too much adverse yaw.

Also tried to set the tailwheel free castering, by editing the respective contact points, but the aircraft continues to taxi very easily and rudder effectiveness is there even at low power / propwash settings. Also everytime you stop, the tailwheel automatically aligns with the longitudinal axis - a long time bug in MSFS never fixed. As anyone who has taxied such an aircraft knows, toe brake using asymmetrically is the only way to control it at taxiing speeds / power settings... and rudder is almost 100% ineffective.

I doubt there is anything more than just the "Magic" of A2A's Accufeel. For instance the Leaning Bug is still there - something that should really be fixed because it causes a completely wrong interpretation of the effects of leaning on any simmer willing to learn how that goes in the real thing...

After all, this all applies to the competition, with their just released 64 bit, so, nothing new - it's still good old MSFS 9 / 10 in the core of the FDM / Engine and basic systems modelling...

[Chock 17,769]

Interesting stuff. I have to bow to the knowledge of those who have more experience of flying the real Piper Cub, since my own experience at the controls of a real Piper Cub comprises in total, of about ten minutes at the controls of a one of my mum's friends' aircraft years ago, and that was before I had my pilot's licence, so I never did either the take off or the landing, just a few turns and what not and I couldn't even tell you which model of Cub it was either. I do recall enjoying it though and being a little apprehensive at first since it was one of the first times I'd been in a little GA aeroplane.

As I said on the original post, the comparison between the two Cubs in FSW and FFSX-SE was in no way a really scientific one, just a try at picking what are about the two closest default aeroplanes in both sims. Since there isn't a Cessna 172 in FSW by default, the Cub seemed like the best choice. With regard to it feeling more like flying a real aeroplane in FSW than other sims, that feeling is not limited to the Cub, I think quite a few of the other default FSW aeroplanes convey that, particularly the Piper Cherokee, which is rapidly becoming a favourite for me, no doubt part of that is the recent release of the Just Flight one too, which I certainly hope ends up being available for FSW, along with their Trinidad and Tobago. And if Lionheart or any other developer manages to get the Bellanca Viking in FSW, I might just find FSW being my favourite flight sim lol.