Bubble Dancer RES Sailplane Ready for Download

Including a new Orientation Trainer feature.

This newsletter starts off with announcing the release of the Bubble Dancer in FS One. It was first mentioned in the last FS One newsletter.

And if you are new and want to follow the newsletter, subscribe here on Substack:

On to the news!

---

Bubble Dancer - Finished and Ready for Download

Screen shot of the Bubble Dancer FS One model

This is a great flying sailplane. At the 31 oz (880 g) design weight, the minimum sink rate is 0.8 ft/sec (0.24 m/s). The max L/D is around 22-23, and it has plenty of control with the "RES" setup - rudder, elevator, and spoiler. The radio is setup with only one flight mode: thermal.

You can get the Bubble Dancer by downloading the latest 2022d FS One update.

Bubble Dancer with full spoiler deployment and up elevator mix.

The Bubble Dancer uses elevator differential: 20 deg up and 12 deg down. There is also elevator-to-spoiler mix that gives about 6 deg of up elevator with full spoiler, which matches the design spec sheet from Dr Mark Drela, designer. The c.g. is set to give zero load on the tail for a CL=0.6, and this c.g. "feels" very good. Nevertheless, if adjustments are wanted, the c.g. is easy to change by editing the airplane in the sim. Adding ballast is easy via the first page in the FS One "Scaling Wizard" editor. To make edits, first click on "Edit" to make a copy and give your copy a new name. After that steps, edits can be made to your copy.

The toughest part of doing the aerodynamics for the Bubble Dancer in the sim was sorting out the performance of the center panel with its large spoiler. XFOIL (airfoil software) cannot predict the effects of a large spoiler, and the sparse data found in the literature could only be used as a guide. I never did any wind tunnel tests with a large spoiler, so no luck there. I might discuss how it finally came together in a later newsletter, but the end result performs very nicely in the sim.

The graphics model ranks as among the best in FS One. It was created by Mark Haley, and he documented it on his Aviator Studio website. The sim model match to the original drawings is exceptional. The nose shape is a modification of the original, and he details the modification on his website. To me, the shape of the nose with a slight amount of droop looks more sleek/nicer than the original design.

Orientation Trainer - New feature with Update 2022d

Have you ever been flying at a far distance and then look away from your airplane and then back again? Then you ask yourself(!): "What direction am I flying". At least I've done this more than a few times. The silhouette plays tricks on the eyes. Is it coming or going?

There is now a new feature in the sim that let's you play these tricks on your eyes in the sim. I'm calling it the "Orientation Trainer". Selecting that option at startup replaces the airplane skins with essentially a dark camo scheme. Then when flying at a good distance away, the airplane looks the same coming or going, so now you can practice how to re-orient if this happens in real life at the field. I'm not sure how others manage it, but I slowly move the rudder/aileron and if I get the expected result, I’m good. Otherwise, I re-orient and try again. With a glider that's low stress, but with a fast foamie jet, a slow test input is best! The screen shot below shows the visual effect of using this feature. In this case, the airplane is flying toward the pilot position, but you cannot tell by looking! The zoomed inset window is of course a ‘cheat’, but it hardly helps.

BVM Bobcat jet in FS One using the Orientation Trainer dark textures.

To use the Orientation Trainer, start the FS One Power Tools for 2022d app. Find the menu named "Orientation Trainer" and check the box (see below). Then start FS One from the FS One Launcher gadget in the Power Tools app. This app runs along side FS One and can be found in the Windows Start menu when the 2022d update installs. Details about how to run the Power Tools app is in a “readme” at the end of the 2022d install process, and more about the new features and how it works is documented in the User Manual.

FS One Power Tools app and new Orientation Trainer menu item.

Next Newsletter

The next newsletter will include mention of the next airplane planned for release. Subscribe to get the news.

About the FS One Newsletter

Subscribers to this "RC Flight Simulation with FS One" newsletter will be among the first to know when new airplanes and new features are planned and released for FS One. I will also discuss some of the finer details that go into RC flight simulation, share tips and techniques for flying, and touch on aerodynamics and flight dynamics now and then. In addition to the usual coverage, keep an eye out for occasional thoughts and ideas on other related topics in RC modeling.