Comet 4c - Testing Update - Performance Check

Happy New Year!

3D Model and ACF

Comet 4C v0.91 was released to testers on 2 December 2011. 29 faults or suggestions were found and fixed.
Comet 4C v0.92 was released on 27 December 2011. 6 further faults or suggestions were fixed.
Comet 4C v0.93 was released on 4 January 2012. I await the results!


A plugin for Rolls-Royce Avon engines is being developed by David Plunkett. It’s primarily to adjust thrust and fuel consumption for pure turbojets which X-Plane does not simulate. It also adds outputs for fuel used per engine and ties throttles in pairs, for JERA sound. Work on the plugin is in progress. Otherwise Comet systems will make the best out of standard X-Plane features as demonstrated on YouTube.


Alternative operator liveries are in progress. This is the critical path at the moment.


There will be two versions of the Comet 4C. A full version, which requires a computer with at least 512 MB VRAM and a low-poly “e” version aimed at computers with 256 MB VRAM.

Initial results have been good, testers reporting that the “e” version was nicely contained within 256 MB VRAM, enjoyable to fly, and achieved frame rates from 25-40 f.p.s. in a range of flying situations on several fairly old computers. More objective tests will follow when the whole model is at a release-intent level. Frame rates on my own computer are shown in the table below.

Polygons Textures Total Perf.
x106 MB U MB C MB U MB C MB f.p.s.
Comet 4C v0.87 0.52 48.7 80.1 48.4 128.8 97.1 57.2
Comet 4C v0.90 — YouTube 0.86 66.3 177.8 78.3 244.1 144.5 48.0
Comet 4C v0.91 1.25 94.2 263.4 88.6 357.6 182.8 48.2
Comet 4C v0.91e 0.77 62.4 65.8 19.6 128.1 82.0 50.0
Comet 4C v0.92 1.25 94.4 263.4 88.6 357.8 183.0 47.0
Comet 4C v0.93 1.26 94.7 263.4 88.6 358.1 183.3 51.5
Comet 4C v0.93e 0.72 57.6 65.8 19.6 123.3 77.2 52.5

“U” = “Uncompressed” — PNG textures with X-Plane texture compression OFF.
“C” = “Compressed” — either PNG textures with texture compression ON, or DDS textures.

Test computer:

Apple MacPro 1.1 2x 2.66 GHz Intel Xeon
ATI Radeon HD 5770 with 1GB VRAM
Mac OS 10.6.8

X-Plane 9.70
Texture resolution: very high
Screen resolution: 1920 x 1200, 32-bit color
Anti-alias level: x2
Anisotropic filter: x16
Pixel shaders: all ticked
Compress textures to save VRAM: not ticked
Lateral field of view: 65 degrees
All other detail set to default
Location: EGKK, on runway 08R, view directly forwards from pilot’s seat
Additional scenery: Ted Davis EGKK loaded.

X-Plane 10

As reported in the last bulletin, I’ve tried the Comet 4C in X-Plane 10, experienced the same dismay about render settings as everyone else, and watched the frame rates improve over several successive betas. On my computer, I get about 35 f.p.s. at KSEA with 3D shading on but HDR off, and 25 f.p.s. with HDR on — so far!

However, I’m not going to be distracted by XP10, but finish the Comet 4C in XP9 first, then investigate any snags with it in XP10.

GMM-P (05/01/2012)

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