The HeliPort support thread

[copterboy]

That's the one sutty....why not the result you expected??

[sutty]

Well I guessed the heli, so it must be, lol, jk. Not sure I'm best placed to know, perhaps Raf will chime in, but as you say, there seems to be a couple of similar peaks, which is what we thought might be the result.

[copterboy]

Battery just charged Sutty, so I'll do another test in a different room. See if I get same result.

4 more test completed with varying results. However, the headspeed I calculated earlier of 1453, seems entirely accurate when compared with phoenix. When flying the cx2 on the sim, I managed to get the headspeed to 1451, and I was climbing at a velocity of 1.5m per second. Given that my heli is probably a bit heavier, because of the battery and frame that same headspeed would have me a steady hover, which is what I was doing when I run the test's.

However my 4 later test gave me 3 varying headspeeds of 1009, 2705!! and 1709. I could possibly put the 2705 down to hovering over the microphone, but the others seems within the range of flying on phoenix for a fast decent and fast ascent. Which when controlling your hover with a real co-ax, could be very real headspeeds.

So returning to Raf's original question, what is the lower limit? If it's to include co-ax's then 1000, seems right on the mark. It certainly ties in with the normal headspeed range for flying on Phoenix. And on the ground at 1000rpm means you would not take off, this happens at about 1150rpm.....So testing seems ok to me

EDIT : Can anyone test it with an MSR?? Otherwise I might have to get Gareth to let me have a go of his...lol

[redbird300]

Some progress in the unreleased tailbelt module today.

It calculates MXL, XL and HTD-3M tailbelts, from teeth to length and the other way around, simply by clicking the up/down arrows in the boxes. It doesn't matter which box you click first, or if you change from one box to another, the calculations will always follow.
There is also a list of common helis with the specs of the stock tailbelts, need to input some more data though.
And it can show a drawing of all 3 types, the "show" button will open a drawing of the type that the user selected in the left box.

Here's the first draft, with an example of a XL drawing:

[redbird300]

A new release of HeliPort is online now: version 0.15.

Changes are:

1) A better user interface for the tachometer: the buttons will disappear when starting the recording, and appear again when the recording is finished. That's a visual aid for the user, to be able to notice easier when the recording has finished. And the "spectrum" button will only be visible when the RPM value has been calculated.
2) Also for the tachometer: an extra menu called "Alert", allowing to activate one of eight selectable warning sounds (or none), which will be played after the delay time + recording.
3) A completely new data module called "Tailbelts". It has a small calculator for 3 different types of tailbelts (+ pictures), and a list of common helis with the specs of the stock tailbelts.
4) HeliPort now automatically remembers some of the users settings when started, like the delay and the sound in the tachometer.
5) A small PDF manual, included in both releases, also downloadable separately.
6) Some minor changes in the code and help files.

Enjoy, it's free as usual: http://users.telenet.be/heliport

[Z900]

Thanks Raf, monday i'm gonna test the Tacho !

[sutty]

Hi Raf, I tried the tacho in HeliPort at various ranges today using my 450. I used the timer feature and the ships fog horn to let me know when I could stop the hover, and I had no trouble hearing it. I used my laptop, and I tested at 10, 20, 30 and 40m ranges. I live in a quiet environment, with little to no background noise, or so I thought. On the first test I had the following successful results.

10m........3230 RPM
20m........3190 RPM
30m........3169 RPM
40m........3129 RPM

The descending RPM value was due to the battery becoming less fresh as I went through the tests, but just in case it was some wierd result caused by distance I decided to reverse the tests with a fresh battery. Starting at 40m. The results were as follows:

40m........1898 RPM *
30m........3190 RPM
20m........3169 RPM
10m........3149 RPM

* This value could clearly be seen to be an error, but there was a rather loud bird, just behind me on the roof of the house, and I am fairly sure that this drowned out the heli, and caused the odd result. Looking at the spectrum you could see a very clear separate spike in addition to the lower frequency one, and it had a value of 3250 or 3230, as the amplitude of both of these were quite close, but less than that of the bird.

So using the spectrum to correct the first value at 40m, the list would look virtually the same as the first list with the value slowly descending as a function of time, and battery condition, and not as a function of distance, which I had some minor concern about after the first round of results.

Having checked sample 1 in Audacity, I can clearly see, and hear, that the bird is louder than the heli, so I think it might be the cause. The bird makes the same or similar noises in the 30m and 20m samples, but the heli wins out I guess.

So, in very quiet conditions, 40m is possible. With some quiet disturbance, well, quite a noisy bird actually, 40m is a little too far, but at 30m it was still fine with the same disturbance. So if we said in fairly quiet surroundings a reading up to 30m is possible, I think that this is more than adequate for the vast majority of requirements, since in reality, it is very easy to hover your heli just in front of you at 5m or less.

A great result I think for the ability of the tool. Congratulations Raf.

EDIT: Samples sent for you to analyse, if you like, as I'm sure you have now received.


Cheers


Sutty

[Ber60]

Wow Sutty nice work

[Ber60]

I've tested the Tacho on the mSR in diff. ways and it is impossible to get a rpm reading in heliport and Audacity.
In short, I did not succeed to measure the rpm of the mSR by sound in any way

[sasa]

thanks for this great app.

But the tacho doesn't work for me :-(
i always obtain 4900 rpm on a 450pro and an outrage 550
I tried close the heli and at 2 3 meters

I use an asus A696 pda with the built in micro
In attach the .wav perhaps it may help

thanks

[redbird300]

Originally Posted by sasa

thanks for this great app.

But the tacho doesn't work for me :-(
i always obtain 4900 rpm on a 450pro and an outrage 550
I tried close the heli and at 2 3 meters

I use an asus A696 pda with the built in micro
In attach the .wav perhaps it may help

thanks

Sasa, I think there is a problem with your PDA: during the first small part of the file I notice that the sound volume is very low, and then it builds up suddenly to a more normal volume. You can even hear it when simply listening to the sound file. This is not normal, and will cause a weird analysis. Your PDA seems slow in starting a recording ?

Secondly, during the whole duration of the sound, I notice a heavy deformation of the sound, it does NOT sound like any of those helis running at all, more like a Chevrolet V8 engine running, lol. BTW, the tacho has been tested on several 450s and 500s, and we never had this problem. Slow and fast, with a lot of different motors, blades and setups, 450pro included.
There might be a lot of reasons for your problem: the metal jacket of your PDA might resonate against another surface, there might be someting loose inside, check for software mic filters and disable them. Also read the help file, you might find some useful tips there.

First thing is of course to take care you have a good recording, as Sutty reported earlier, even distances of 40 meters are possible. Don't hold the mic in the turbulence, but I guess you already know that.

A simple and conclusive test for you would be that you do the same recording with the desktop/laptop version, and see if the problem persists. This will be very unlikely. The tacho code is the same for both versions, so this won't make any difference.

I looked at your spectrum, and the amplitudes as such are OK, but not the spectrum: no clear peaks, indicating a very noisy environment (besides the heli of course), or other vibrations in your recording device that completely blew away the correct signal.

Feel free to come back and post your findings after that, we'll try to help you out.

[Ber60]

Too late Raf anwsered

[redbird300]

Sut, thanks a lot for your detailed tests and reports, I think 'm gonna use some of this stuff to inlcude in the help file for the tachometer .
Nice to know that even at 30 meters or more, the tacho does work.
Distance does not play a role indeed, the only thing is that a very fast moving heli would be more difficult to measure, as the Doppler effect would come into play. Don't see the real use of such a test though, as you could also measure at 100% throttle while simply hovering, with the right throttle curve of course.

[sutty]

No probs Raf, I had fun doing it. Funnily enough I was thinking about doppler effect and wondering what results might be obtained if someone else were to record it for me as I whizzed away or towards, since it was coping with such large distances. Would be fun to try, just out of interest.

Also thought about the GPS data module. I once saw a 3D flight path mapped of an airliner that was in severe trouble. The path was mapped from the information captured by the flight data recorder, and you would not like to have been on that flight, believe me, but that aside I wondered if something like that might be possible from the data that could be provided from the GPS module in HeliPort, or am I being a little ambitious here. A self scaling 3D map, and track, if you will. Is that possible?

Cheers

Sut

[Ber60]

Whoooo Sutty, that what Raf and me where talking about yesterday, mapping it on google earth and see where you crash in 3D should be fun

[redbird300]

Indeed guys, it is possible. Let's say a simple 2D graph of the flight will be easy to realise. A real 3D map, that's another thing, but not impossible. HeliPort already uses the coördinates internally to make calculations, it's just a matter of using these to plot the flight, and optionally put the right satellite map underneath that drawing.
Anyway, these are all possible ideas I keep in mind. These could be realised after HeliPort version 1.00 will be relased. For now, I focus on basic fonctionality off all the promised tools, and only after that, I'll start doing such stuff, probably next winter. Keep the ideas coming ! I keep track of all of these, and the list is growing.

[dauste]

Distance does not play a role indeed, the only thing is that a very fast moving heli would be more difficult to measure, as the Doppler effect would come into play. Don't see the real use of such a test though, as you could also measure at 100% throttle while simply hovering

Hi Raf, not sure if you noticed that the guy that did the Audacity tacho also has a speed trap calculator based on audio recording and doppler effect during a fly past?

D

[redbird300]

Originally Posted by dauste

Hi Raf, not sure if you noticed that the guy that did the Audacity tacho also has a speed trap calculator based on audio recording and doppler effect during a fly past?

D

Indeed, I noticed that. I figure the GPS logger gives accurate speed readings, so that would be two speedometers in one single application if I would try to make such a thing. Looks a bit overkill, or not ?
I'm very curious to hear if you already managed to fly with the GPS logger activated ? I'm still waiting for the first testimony of someone actually using it in a heli. Would be great to hear if you could report on that. I mean, I know it works well, but it would be nice to hear some other experiences.

[sutty]

If I had such a device, it would have been strapped to mine just now. Might just have to buy one, just because I could do just that.

[redbird300]

Because of some short messages and announcements that were posted at several forums, the very basic HeliPort website is doing fairly well. We got over a thousand unique visitors in the last eight days from 27 different countries, most of them from the U.S., the U.K., the Netherlands and Germany, in this order. It's always hard to make a start.
My thanks to all the people helping me with this by posting messages or mentioning it on their own websites, it's sure motivating to get some feedback, and continue the project until the end. That is, if it will ever end, lol.