Upcoming AltimeterThree Enhancements

[John Beans]

I've already shared with one or two members, so I thought I would share more broadly.

In the next few weeks we'll be pushing a new version of the AltimeterThree app to add some additional flight analyses.

Here's a look at the Info screen, in which you can see the added items. Fans of AltimeterTwo will recognize some of these, and you can also see that AltimeterThree is "Chute Release savvy," as it will automatically measure both the initial tumble/drogue descent rate as well as the final landing speed.

What's cool is that these will automatically be applied to your existing flights, such as this North Coast Archer SA-14 flight on an I204 I flew back in October.

 

[WillMarchant]

Thanks for the new features, John!

 

[woferry]

Excellent, thanks a bunch, John! That it can be applied to existing flights is even awesomer!

I think I still had cases even with the latest A2 firmware where eject was being mis-detected at burn-out. Is the algorithm the same here, or would it realize that the rocket continued to climb way after where it initially thought apogee was, or any other reason why things might be different here? Looking back I guess I only flew my newest A2 once (I only had a 38mm MD for a while so it only flew with the A3), and that was a flight that exceeded the accelerometer's max so a bunch of readings were jacked (top-speed, peak-accel, avg-accel, coast-apogee, apogee-eject, ejection altitude and descent speed were all bogus), so maybe that was a different problem due to the accelerometer clipping?

 

[WhatGoesUp]

Thanks John, I am always impressed with your products. I currently own an Altimeter 3 and the Chute Release! I appreciate your enthusiasm for rocketry! I can't wait to see what's next!

 

[Marty]

Earlier today, I emailed [email protected] with a question about my recently-purchased Altimeter 3. I was disappointed that the Altimeter 3, as currently configured, does not calculate top speed. I was unaware of this fact when I purchased my Altimeter 3 (my fault, I know). To me, this is a glaring deficiency, given the Altimeter 3's price point and the fact that the Altimeter 2, which is less expensive, calculates top speed.

To his credit, John answered my email within two hours and told me about the upcoming enhancements to the Altimeter 3. I hope these improvements come as soon as possible.

Thanks, John.

 

[chrisudy]

Very cool. My Alt 3 is waiting for the arrival of my chute release! Shipped yesterday.

Chris

 

[jrkennedy2]

Just bought my Chute Release. Last Sat I had an 8400' walk on a 6800' flight so I decided enough, Chute Release will fix that... Altimeter Three looks like a next purchase. My A2 works well though.

 

[John Beans]

Excellent, thanks a bunch, John! That it can be applied to existing flights is even awesomer!

I think I still had cases even with the latest A2 firmware where eject was being mis-detected at burn-out. Is the algorithm the same here, or would it realize that the rocket continued to climb way after where it initially thought apogee was, or any other reason why things might be different here? Looking back I guess I only flew my newest A2 once (I only had a 38mm MD for a while so it only flew with the A3), and that was a flight that exceeded the accelerometer's max so a bunch of readings were jacked (top-speed, peak-accel, avg-accel, coast-apogee, apogee-eject, ejection altitude and descent speed were all bogus), so maybe that was a different problem due to the accelerometer clipping?

Refined algorithms in AltimeterThree, plus if it misdiagnoses an event like where ejection occurred, you can manually identify the correct data point.

 

[hball55]

I've already shared with one or two members, so I thought I would share more broadly.

In the next few weeks we'll be pushing a new version of the AltimeterThree app to add some additional flight analyses.

Here's a look at the Info screen, in which you can see the added items. Fans of AltimeterTwo will recognize some of these, and you can also see that AltimeterThree is "Chute Release savvy," as it will automatically measure both the initial tumble/drogue descent rate as well as the final landing speed.

What's cool is that these will automatically be applied to your existing flights, such as this North Coast Archer SA-14 flight on an I204 I flew back in October.

View attachment 284748 View attachment 284749

That first screen, are all these NEW or are some of these already part of the Altimeter 3 info. All I see right now is the chart and the info screen, but the info screen doesn't show anything but mode, date, alt., duration. I suppose the altimeter 3 unit shows more, but since I have the app, I didn't bother looking at the alt 3 for more info . . . oops!

 

[John Beans]

These are going to be in next app release.

 

[BEC]

Looking forward to it - and I like that the added data will be available for existing flight data! My iPhone says it has 64 flights' worth of data in it.

 

[Danomite45]

Thanks!
I really miss not having the max speed on the Altimeter Three like there is on the two.
BTW: 5 of myflights today used the Altimeter Three and two used the 'Chute Release.
Thanks for the upgrade!
Daniel

 

[WoShuGui]

Looking forward to the update. On a related note, has anyone else had trouble getting charts to display? I can select the flight and the Info displays fine, but when I select Chart, it shows "Building flight graph..." and the the Altimeter Three app on my HTC hangs.

 

[John Beans]

Looking forward to the update. On a related note, has anyone else had trouble getting charts to display? I can select the flight and the Info displays fine, but when I select Chart, it shows "Building flight graph..." and the the Altimeter Three app on my HTC hangs.

Sometimes downloads got munged a bit if the accelerometer data (which is 3X the size of the altitude data) didn't complete fully. I'm adding a flight repair feature, and more robustness to downloads, including downloads where your battery dies (lost rocket, for instance).

 

[WoShuGui]

Sometimes downloads got munged a bit if the accelerometer data (which is 3X the size of the altitude data) didn't complete fully. I'm adding a flight repair feature, and more robustness to downloads, including downloads where your battery dies (lost rocket, for instance).

Thanks. That makes sense. The problem seemed to start after I enabled accelerometer display on the Chart. Of course now I can't get into Chart to clear it. :smile:

Edit: With the download hint I re-installed the app and did some testing. It turns out in my case that the Extra ground data was the culprit. As long as I don't try to show Extra ground data the Chart works fine.

 

[John Beans]

Here's another peak at what the upcoming enhancements to AltimeterThree will look like.

As I mentioned, the enhancements will apply to your past flights as well. This example is an actual flight of mine from November. All of the marks on the graph are auto-generated. Notice that the burn time is highlighted on the graph, and that AltimeterThree provides both tumble and landing descent rates (a la Chute Release or dual deployment).

It also analyzes your ejection delay, flagging it as "early" sometimes. You'll be able to glance at the graph and see how long your motor provided thrust and how long the delay ACTUALLY was.
And speed, of course.

 

[Charles_McG]

Calculation of C(d) from the burnout to apogee or eject data?

 

[John Beans]

Calculation of C(d) from the burnout to apogee or eject data?

It could certainly look at the coast deceleration curve and get most of the way there, although it would need to know the weight of your rocket and its frontal area to calculate Cd. It could either provide you an "deceleration vs. velocity squared" parameter you can use, or require you to enter the weight and frontal area so that it could finish calculating the inferred Cd after each flight.

Not a bad method, as long as the measurements were taken during relatively vertical flight. By looking at "early coast" mostly, trajectory error could be reduced. High thrust motors would be better than longer-burning ones, because the decel curve is more dramatic then (read: the Cd affects performance more dramatically at higher speeds).

Let me know if Cd is something folks care about?

 

[Charles_McG]

You could take a picture of the nose end view of the rocket, auto trace the outline, select the biggest diameter from a tube list and calculate the area .

 

[woferry]

Let me know if Cd is something folks care about?

I'd never say no to more data.

Not a bad method, as long as the measurements were taken during relatively vertical flight.

Wouldn't the accelerometer help in determining whether it was a 'relatively vertical flight'? Assuming it was 'relatively vertical' while sitting on the pad? Of course if it's loosely-mounted it could move around during the flight, but if it's more rigidly-mounted it should be a decent indicator I'd think.

 

[John Beans]

Wouldn't the accelerometer help in determining whether it was a 'relatively vertical flight'? Assuming it was 'relatively vertical' while sitting on the pad? Of course if it's loosely-mounted it could move around during the flight, but if it's more rigidly-mounted it should be a decent indicator I'd think.

Well, not really. You're free to mount it any way you want, and just because AltimeterThree reads 10 degrees prior to launch, it doesn't mean your launch rod's at 10 degrees. And of course during flight it can't tell what angle it's at.

It would just have to assume it's near vertical, and the user would have to be aware that "the more vertical, the more accurate." Not that 5 or 10 degrees would matter much. The velocity squared dominates the calculations, and sine(5) is a fairly small number.