Viper poor performance?

[giovanniluigi]

I just added the Viper (turbine, giant scale) jet, as a la carte purchase from the new 2024 pack, and I am running it on the new Beta.

Can someone tell me if this is normal:
1. very lethargic performance: it seems to fly very slow (especially compared to the 90 mm EDF Viper) and any movements (e.g. retracts) appear to be in slow-motion;
2. I don't see where I can enable to cockpit view, referred to in the description (F4 on the keyboard only reverts out of the app).

Am I doing something wrong or is there some bug?

Thanks

 

[Ryan Douglas]

EDIT: Updated to correct the ViperJet's wingspan.

@giovanniluigi, the important thing to note is that the ViperJet is a very large scale turbine model.

Larger models always appear slower in the sky due to their size. And parts like retracts are much larger and move more slowly on a scale model like this compared to a small model with tiny gear.

The ViperJet is actually pretty sporty for its size, but its 11.4 foot (3.5 meter) wingspan means it will fly and feel quite a bit different than the 4.6 foot E-flite Viper 90. That contrast is normal and expected.

Turbines also take longer to spool up and down than tiny EDF fans, increasing the time it takes to get to speed.

The ViperJet was tuned by top large-scale turbine pilots, and we're confident it is an accurate representation of that experience. As always, though, RealFlight's powerful vehicle editor lets you save a custom variant of any model and modify it to your liking, including increasing thrust and speeding up the moving parts!

To switch camera modes, which is what the cockpit view requires, you must be at a 3D (i.e., non-PhotoField) airport. Pressing F4 at a 3D airport with the ViperJet loaded should jump straight to that camera view. Alternatively, you could press the 'C' key to cycle through available views until you get there.

Alt-F4 is a standard Windows keyboard shortcut for exiting a program. If pressing just F4 is closing RealFlight, I wonder if you have a stuck Alt key...

 

[giovanniluigi]

@giovanniluigi, the important thing to note is that the ViperJet is a very large scale turbine model.

Larger models always appear slower in the sky due to their size. And parts like retracts are much larger and move more slowly on a scale model like this compared to a small model with tiny gear.

The ViperJet is actually pretty sporty for its size, but its 15 foot wingspan(!) means it will fly and feel quite a bit different than the 4.6 foot E-flite Viper 90. That contrast is normal and expected.

Turbines also take longer to spool up and down than tiny EDF fans, increasing the time it takes to get to speed.

The ViperJet was tuned by top large-scale turbine pilots, and we're confident it is an accurate representation of that experience. As always, though, RealFlight's powerful vehicle editor lets you save a custom variant of any model and modify it to your liking, including increasing thrust and speeding up the moving parts!

To switch camera modes, which is what the cockpit view requires, you must be at a 3D (i.e., non-PhotoField) airport. Pressing F4 at a 3D airport with the ViperJet loaded should jump straight to that camera view. Alternatively, you could press the 'C' key to cycle through available views until you get there.

Alt-F4 is a standard Windows keyboard shortcut for exiting a program. If pressing just F4 is closing RealFlight, I wonder if you have a stuck Alt key...

@Ryan Douglas, thank you for the quick reply.
I did not quite realize how big the "physical" Viper model was (15 ft) and the default visual size set at 76% did not help either. Your explanations make sense to me. I will probably try to tweak things a bit, especially add a mix of down elevator to flaps, as I feel the Viper tends to go up a bit when flaps are deployed.
As for the 3D vs PhotoField, that was exactly the reason I was not able to get the cockpit view. Maybe the description could mention that requirement. Now it works as stated, when I correctly press F4 (I was not selecting the other key for fn together with F4 and was getting some Home function instead).
Thanks again for your help.

 

[Ryan Douglas]

I'm glad that was helpful!

The Vehicle Graphical Scale being 76% won't actually affect your experience, because the visuals and the physics match each other.

The vehicle art and the vehicle physics have their own sizes independently of each other. The art is not unitless; it is inherently and unavoidably created with certain dimensions. Typically we are careful to have our artists model things at exactly the right size, and as a result nearly all the stock content has a graphical scale of exactly 100%. But occasionally with a model like the ViperJet that is based on a full scale design instead of a specific RC model, we don't know at the outset what we will choose for the final vehicle size. Sometimes in that situation we settle on a good size for the model well after the art is complete, and rather than the artist rescaling the entire thing we just adjust it in RealFlight using that property.

Where things can get screwy is when the visuals and physics dimensions do not match. The greater the disparity, the more problematic. Let's use a couple extreme examples to illustrate the issues.

Imagine an ultra-micro airplane with its visuals scaled up to the size of a jumbo jet. Now imagine it flying from one end of your local flying field to the other at typical ultra-micro speeds. The physics, not the visuals, are what control the actual flight behavior, so it'll take a while. But remember, it looks like a jumbo jet! A jet making that same trip at tiny RC model speeds will look incredibly slow--more like a blimp than a jet. Further, imagine that "jet" doing a 180-degree turn with a 10-foot radius. It will look very wrong!

Going the other way, imagine a jumbo jet physics setup with the visuals scaled way down to the size of an ultra-micro RC model. Imagine it making that same flight from one end of the flying field to the other. At several hundred miles per hour it will get across in no time. But remember, what you will see is an RC model seeming to almost teleport from one end to the other.

The bottom line is that because we have configured the ViperJet power, weights, etc. for its actual physics size and merely used the graphical scale to make the art match that setup, it will behave exactly the same as if the art had been created 76% smaller and the visual scale in RF was 100%. (The Cirrus Vision SF50 is another example of this happening. In that case the art is scaled up to match the physics instead of down.)

 

[giovanniluigi]

I'm glad that was helpful!

The Vehicle Graphical Scale being 76% won't actually affect your experience, because the visuals and the physics match each other.

The vehicle art and the vehicle physics have their own sizes independently of each other. The art is not unitless; it is inherently and unavoidably created with certain dimensions. Typically we are careful to have our artists model things at exactly the right size, and as a result nearly all the stock content has a graphical scale of exactly 100%. But occasionally with a model like the ViperJet that is based on a full scale design instead of a specific RC model, we don't know at the outset what we will choose for the final vehicle size. Sometimes in that situation we settle on a good size for the model well after the art is complete, and rather than the artist rescaling the entire thing we just adjust it in RealFlight using that property.

Where things can get screwy is when the visuals and physics dimensions do not match. The greater the disparity, the more problematic. Let's use a couple extreme examples to illustrate the issues.

Imagine an ultra-micro airplane with its visuals scaled up to the size of a jumbo jet. Now imagine it flying from one end of your local flying field to the other at typical ultra-micro speeds. The physics, not the visuals, are what control the actual flight behavior, so it'll take a while. But remember, it looks like a jumbo jet! A jet making that same trip at tiny RC model speeds will look incredibly slow--more like a blimp than a jet. Further, imagine that "jet" doing a 180-degree turn with a 10-foot radius. It will look very wrong!

Going the other way, imagine a jumbo jet physics setup with the visuals scaled way down to the size of an ultra-micro RC model. Imagine it making that same flight from one end of the flying field to the other. At several hundred miles per hour it will get across in no time. But remember, what you will see is an RC model seeming to almost teleport from one end to the other.

The bottom line is that because we have configured the ViperJet power, weights, etc. for its actual physics size and merely used the graphical scale to make the art match that setup, it will behave exactly the same as if the art had been created 76% smaller and the visual scale in RF was 100%. (The Cirrus Vision SF50 is another example of this happening. In that case the art is scaled up to match the physics instead of down.)

View attachment 139078

Thanks for the detailed response.
My point (perhaps incorrect) was exactly related to your "Where things can get screwy is when the visuals and physics dimensions do not match." I thought that the ViperJet does fly like a 15 ft wingspan model (just as you described in your first post, because of its physics), but it looks like a smaller plane (11.4 ft ws, because of the visual scale), hence the slight disconnect in my experience.
But I may be wrong....
Thanks anyway

 

[Ryan Douglas]

I need to correct part of what I said above. I will edit my earlier post with a note after this.

It turns out the ViperJet actually does have an 11.4 foot wingspan, not 15. The indicator I checked to get its size apparently gives the unscaled size of the visuals. I have filed a bug report about that. (That's something we probably would have noticed sooner if stock models with a value other than 100% were not such outliers.)

Everything else I said is still correct. The important thing is that the visuals and physics dimensions match each other.

In this case, the ViperJet should both look and fly like an 11.4 ft (3.5 m) wingspan jet.

Just to help visualize, here is the difference between visuals and physics with the graphical scale set to 100% (giving visuals their original 15 foot wingspan):


If we go the other way and reduce the visuals to 76% of their current size (so ~58%), it looks like this (resulting in an 8.7 ft. visual wingspan, well under the 11.4 in physics):


Anyway, I do hope that helps! Sorry for my initial error about the actual dimensions!

 

[giovanniluigi]

I need to correct part of what I said above. I will edit my earlier post with a note after this.

It turns out the ViperJet actually does have an 11.4 foot wingspan, not 15. The indicator I checked to get its size apparently gives the unscaled size of the visuals. I have filed a bug report about that. (That's something we probably would have noticed sooner if stock models with a value other than 100% were not such outliers.)

Everything else I said is still correct. The important thing is that the visuals and physics dimensions match each other.

In this case, the ViperJet should both look and fly like an 11.4 ft (3.5 m) wingspan jet.

Just to help visualize, here is the difference between visuals and physics with the graphical scale set to 100% (giving visuals their original 15 foot wingspan):
View attachment 139087

If we go the other way and reduce the visuals to 76% of their current size (so ~58%), it looks like this (resulting in an 8.7 ft. visual wingspan, well under the 11.4 in physics):
View attachment 139090

Anyway, I do hope that helps! Sorry for my initial error about the actual dimensions!

Got it. To summarize: the visual (graphics) was created a bit larger than it eventually was needed and the visual scale of 76% was used to bring the visual down to match the physics, which is for a 11.4 ft wingspan model.

So, what I perceived as sluggish behavior of the ViperJet is really "as designed".

As suggested, using the vehicle editor I made a few simple changes: 1. increased the turbine thrust to 50 lbs, to achieve a 1:1 thrust-to-weight ratio; 2. increased the speed of the retracts (servos speed from 4.0 to 2.0); 3. added a down elevator to flaps mix (-5% at half flaps and -10% at full flaps). Now the ViperJet flies the way, in my opinion, this jet should really fly: all good!