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AcroBox: an app for aspiring aerobatic pilots

ChiefPilot

Well Known Member
This past summer, I became somewhat interested in competition aerobatics. Joining the local IAC chapter, I found that one of the biggest challenges was being able to stay "in the box". The aerobatic box as defined by IAC rules is a 1km x 1km box starting from 328'agl to 1500'agl and going up to 2000' to 2952' feet (full details here).

Staying in the box wasn't hard because it is small but rather because knowing where it's boundaries were is difficult unless you're at a chapter meeting where the markers are out or at a competition meet. Moreover, any practice area needs be compliant with FAR 91.303 - away from airways etc. This was somewhat time consuming to do on a normal flight planning app. As an app developer, I knew there was a way to solve this problem.

The result is AcroBox for iPhone and iPad.

AcroBox lets you define the boundaries of a virtual aerobatic box compliant with the International Aerobatic Club's specifications and FAA regulations. Use the VFR and IFR charts to ensure that the box doesn't encroach on federal airways or airport surface areas, then use the aerial map to visually identify box boundaries. If you're setting up a box for a club or competition event, the "marker" mode shows exactly where the box markers should be placed.
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If you have multiple devices, AcroBox lets you easily share box locations between them using iCloud. You can also share box details with other pilots via e-mail, and they will receive not only the coordinates of your aerobatic box but also a map image and a link to open the box in AcroBox or another popular flight planning app! Share your box definitions on Facebook, Twitter, or simply export them directly to ForeFlight - AcroBox is all about sharing.

One feature that is somewhat experimental is the "virtual boundary judge". When in "fly" mode and connected to the aircraft audio system, the app will audibly announce box enter/exit events. I say experimental because the GPSes in phones especially are horrible and lose position readily during manuvering. The GPS in an iPad Air/Air2 works ok but loses position occasionally. I'm interested to find out if external GPSes (Stratus, Stratux, etc.) work any better. If you want to try this, make sure the silent/vibrate switch is off - AcroBox honors the switch's setting.

The app is available on the Apple AppStore free of charge and free of ads. Aviation is expensive enough as it is.
 
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AcroBox App +1

WOW, what a great tool. I?ve already created 4 new boxes close to my home airport and can?t wait to go flying and try them out.

Now, if we could just set up a remote, pilot activated camera close to one of those boxes that we could record our practice it would be complete.:rolleyes:

Thanks for doing this Brad.
 
Wow an early x-mas present!

Looks greate already put the box in my acro spot.

As for your GPS question I experimented with that quite a bit as I wanted to record my loops all the way around. So with my regular Dynon GPS which is mounted on the top of the airplane accuracy regularly became unusable as soon as I went through the vertical as my fuselage would interfere with line of sight to the satellite. Would recover accuracy within 1/2 second or so of the end of the loop. After some disussion on the topic on the Dynon messaging board I ended up building myself a little GPS recorder (spark fun parts 60$) I put in the wingtip. Haven't lost reception since. So it's all in the position of your GPS. I would suspect a Sratus in the wing tip would work greate but haven't tried a stratus in particular.

Now some suggestions for improvement.

Seems the area around the box is just a 5 mil radius. Regulation calls for 4 miles of the center line of an airway. So what you really want is to shade the area within 4 miles of the box outer boundary. Believe it or not in my area ( northern NJ ) that makes the difference of being legal or not..... .

Thx again for a greate app. Can't wait to try it in the RV.

Oliver
 
Looks like a nice app to help locate a decent practice area, hopefully with some landmarks close to at least the limits of the X-axis. For anyone who just wants to layout a box at home on the PC, there's a box calculator tool here -

http://serega.aero/boxCalc/acrobox.html

As far as inflight notifications, I might caution against trying to use too much technology to learn to keep a flight inside the box, since in contest flying, it's purely a visual/SA exercise. Each flight is different, as wind conditions can vary widely. Newbies have a hard time staying in the box due to their brains being saturated with simply flying the individual figures, with few resources left to maintain good SA/box position. It's a skill you must develop the same as doing the individual figures. It gets easier as the task saturation with simply flying the airplane drops. Practically none of us see an actual marked box outside of a contest. So we do these best we can during practice. Flying next to a 5000' runway and staying inside the 1000' stripes works well. Sometimes you can get lucky and find a practice area with prominent landmarks that are very close to the box length.

In low/mid/bi-wing aircraft (almost all aerobatic airplanes), seeing the box is nearly impossible in straight and level upright flight. So you must use the opportunities to note your box position when they present themselves. There are lots of places. First is using a steep bank angle during your wing wags to precisely monitor your box entry. Vertical and 45 downlines work well. So does inverted flight (N/A in Sportsman unless you fly a Free sequence). It's always a challenge, but it gets easier.
 
As far as inflight notifications, I might caution against trying to use too much technology to learn to keep a flight inside the box, since in contest flying, it's purely a visual/SA exercise. Each flight is different, as wind conditions can vary widely. Newbies have a hard time staying in the box due to their brains being saturated with simply flying the individual figures, with few resources left to maintain good SA/box position. It's a skill you must develop the same as doing the individual figures. It gets easier as the task saturation with simply flying the airplane drops. Practically none of us see an actual marked box outside of a contest. So we do these best we can during practice. Flying next to a 5000' runway and staying inside the 1000' stripes works well. Sometimes you can get lucky and find a practice area with prominent landmarks that are very close to the box length.

The annunciations are nice for working out timings and such and aren't intended to tell you when to pull/turn/etc. The biggest benefit is that it provides an option when there's noone else around and no box markers handy. I would not suggest it as a replacement for a boundary judge, nor did I, but rather as an aid when no one else is available. You really think they are a bad idea in that context?

The app also has the benefits of being a "live" GPS when laying out box markers. The methods I've learned of thus far don't seem nearly as straightforward.
 
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The annunciations are nice for working out timings and such and aren't intended to tell you when to pull/turn/etc. The biggest benefit is that it provides an option when there's noone else around and no box markers handy. I would not suggest it as a replacement for a boundary judge, nor did I, but rather as an aid when no one else is available. You really think they are a bad idea in that context?

Not saying it's a bad idea, I just feel it has limited application to learning to fly your sequence inside the box in the way that will be required when you're actually up there in front of the judges. Timing between figures can be all over the place depending on wind conditions. Even though pilots go out on the Y-axis of the box much less often than the X-axis, you must also monitor your Y-axis position to present your flight well to the judges. It's not just about staying inside the box. It's also about good presentation.

But I'd be interested in your continued experience using this tool as you keep practicing. I've just not had experience with anyone doing this. Even with boundary judges in place, you don't get a real time report of when you're in or out. They report via radio to the chief judge assistant, not the pilot. I've never heard of anyone monitoring boundaries on Chapter practice days either. You only get a report of boundary infringements when you're able to view your score sheets on the ground after the flight. Usually, the penalty form just confirms what the pilot already knew (or suspected) about their flight.
 
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any instructions???

:confused::confused:
Brad,
I down loaded the acrobox app, but can't figure out how to use it. I'm familiar with the other mentioned aerobatic box drawer where it had a menu to position the box after you found the geographic location. After I found a location and hit the fly, mark, or edit buttons, I end up in the north Atlantic. Is there a help section or some simple instructions? Remember I was born before WWII, so the computer stuff can be very challenging.
Cheers,
Bill McLean
RV-4 slider
lower AL
 
Hey Brad,

That looks like a cool app. Thanks for sharing. Any chance the Canadian VFR sectionals can be added?

Thanks,

Jeff
 
:confused::confused:
I down loaded the acrobox app, but can't figure out how to use it. I'm familiar with the other mentioned aerobatic box drawer where it had a menu to position the box after you found the geographic location. After I found a location and hit the fly, mark, or edit buttons, I end up in the north Atlantic. Is there a help section or some simple instructions? Remember I was born before WWII, so the computer stuff can be very challenging.
Cheers,

Shoot me a private message with the details (type of phone, version of iOS, etc.); I'd be happy to investigate further.
 
That looks like a cool app. Thanks for sharing. Any chance the Canadian VFR sectionals can be added?

It's possible, but the problem is a financial one and not a technical one. As far as I know, NavCanada doesn't make a GeoTIFF or other georeferenced digital version of the sectionals available for free - if you know of a source I'd certainly be happy to investigate it.

Thanks!
 
village idiots can learn

Brad,
I uploaded IOS 9.2 (didn't realize the update), and the acrobox works GREAT.The instructions at the beginning, which I didn't see before, are very clear. I've already starting saving boxes in the favorites. I hope you post this on the acro aerobaticsweb or IAC site so all us vertical and inverted types can benefit.
Thanks again,
Bill McLean
RV-4 slider
lower AL;)
 
Thank you so much! This is awesome. Unfortunately, my Piper does not like it upside down.

... Stop distracting me from finishing the -8.
 
Thanks Brad. I did some checking and like you pointed out, haven't found a source for inexpensive or free charts. Darn NavCanada. Grumble Grumble.
 
Followup

This past weekend, IAC Chapter 78 had a practice day at the Litchfield Municipal Airport (KLJF) and the box associated with it. I flew five times in front of the people judging and coaching (one of whom is on the US Aerobatic Team - Craig Gifford). This was the first time I've ever flown in a "real" box, although I've been using this app quite a bit during it's development starting last year.

While I need some work on inverted 45 degree downlines, staying in the box wasn't a problem - in fact, one of the judges said that for someone who's never flown in a box before, I had no issues with staying in the box or making sure to keep the presentation in front of the judges. Seeing the box on the ground was great but I already knew what I needed to do to correct for winds, timing between figures, and so on. I think the app was a *huge* help with this.

I hope this doesn't sound like a sales pitch - I'm just really happy with how well the app helped me achieve the objective I set for it. I hope others find it useful and that it can remove at least some of the unknowns around what IAC flying is about.
 
Any plans for an Android version? :)

Used to be "No" but is now "Maybe". I enjoy writing iOS apps for both work and fun but have only done Android apps when paid to do so. Still, there's been enough inquiries that it might happen. The big hassle with Android of course is the fragmentation and support for wildly difference screen sizes etc. It will look/work well on Nexus phones; anything else will likely be a bonus since I don't have one of every type of Android device to test on :)
 
Brad,

I just downloaded your app. It's awesome! Thank you so much.

Thanks for trying it out! It was useful for me to understand how to stay approximately in the box, and it's still very helpful for finding potential boxes nearby.

I've got a new version close to going up that adds support for AirDrop and more - I hope to get it into the AppStore in the next couple of weeks.

Thanks!
 
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