Launch in progress for Ichthus College, Veenendaal, NL

[Nick McCloud]

Trackers online, HorusBinary on 434.714 but LoRa didn't get changed so is on 434.000

[David Brooke]

On Wed, Jan 21, 2026 at 02:18:17AM -0800, Nick McCloud wrote:
> Trackers online, HorusBinary on 434.714 but LoRa didn't get changed so is
> on 434.000

Curious, ICHTHUSLORA is reporting 434.000 yet other receivers are
reporting around 432.666

I'm listening on the latter but it may well burst before coming into
range here.

David G6GZH

[David Brooke]

On Wed, Jan 21, 2026 at 11:12:47AM +0000, David Brooke wrote:
>
> Curious, ICHTHUSLORA is reporting 434.000 yet other receivers are
> reporting around 432.666
>
> I'm listening on the latter but it may well burst before coming into
> range here.

Well I'm receiving it. The Horus was first, but now also LoRa. It's
exceeding the predicted burst height by a fair bit!

BTW Nick, as I believe you intend to fly the same configuration again,
it might be worth seeing if you can get the burst height set on sondehub
for future flights so that the pre-burst live prediction is more
accurate.

David G6GZH

[Nick McCloud]

On Wednesday, 21 January 2026 at 11:52:03 UTC David Brooke wrote:

On Wed, Jan 21, 2026 at 11:12:47AM +0000, David Brooke wrote:
>
> Curious, ICHTHUSLORA is reporting 434.000 yet other receivers are
> reporting around 432.666

User error I suspect.

 

>
> I'm listening on the latter but it may well burst before coming into
> range here.

Well I'm receiving it. The Horus was first, but now also LoRa. It's
exceeding the predicted burst height by a fair bit!

Indeed. I've just weighed my 2 x 50g Hwoyee balloon package and they are 50g. And the launch picture I've seen looks inline but who knows.

BTW Nick, as I believe you intend to fly the same configuration again,
it might be worth seeing if you can get the burst height set on sondehub
for future flights so that the pre-burst live prediction is more
accurate.

For sure, I would have but my remote colleague was suffering from overload last night.

And clearly we need to calibrate these balloons a bit better. Or get Steve to supply 'proper' ones, even though these did come from Hwoyee in China, allegedly, via Amazon.

[Nick McCloud]

Small balloon, check.

Party Helium, check

What the heck is up with the height?

[Nick McCloud]

Thanks to the multitude of people that helped with tracking from far & wide across the Netherlands and even in to middle England!

There was an issue with the SDR for Horus in the car but they had LoRa for most of it, shut down to save battery as flight time was far more than expected, and bought it back online once it had burst.

Loss of Signal, a short drive towards the last know position, park up and pick it out the grass. One of the simplest retrieves ever.

We'll have to debug the balloon issues. And I need to analyse the descent data to check my "stout plastic bag" parachute design for size. So I'll report back here when we've done some processing.

[Steven Boonstoppel]

The Dutch colleague here - thank you all very much! With the balloon reaching an altitude of 21km instead of 8km and the flight time being pretty much triple the original expectation, my laptop battery couldn't keep up while also powering the SDR and LoRa receiver. It was very comforting to see plenty of receivers tuned in so I could leave the last 30% for the descent. We had a blast seeing the altitude go up and up and are fortunate that everything worked out so well despite the insane height for what should be a simple 50g balloon.

And most thanks to Nick for being the Remote Launch Director and working overtime to support me <3

Op woensdag 21 januari 2026 om 14:33:09 UTC+1 schreef Nick McCloud:

[Steve]

It wasn't a surprise to me.  A 50g balloon + 50g payload should regularly get to that altitude or more.  There have been several HY-30 launches in Europe recently that have been turning in those sort of burst altitudes (and even higher).

The burst predictors are producing numbers that are way out for small balloons - mainly because the manufacturer data is way out too (both burst diameter and average burst altitude).

If folk feed me their data (balloon, payload weight, free lift and/or ascent rate) I can introduce more accurate variants on the burst predictor.

    Steve G8KHW

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[Nick McCloud]

On Friday, 23 January 2026 at 14:42:42 UTC Steve wrote:

It wasn't a surprise to me.  A 50g balloon + 50g payload should regularly get to that altitude or more. 

Meh, should have chased you up in October!

It was actually lifting 131g from a design of 100g using the RE calculator for a fill of a complete canister of 50 x 9g party balloons. The thinking being that rather than hack around with float etc, we work backwards.

Descent weight with the (substantial) balloon remnants was 168g and yes, there was a lot of latex to make that weight up, analysis of the DIY 17" chute to follow.

If folk feed me their data (balloon, payload weight, free lift and/or ascent rate) I can introduce more accurate variants on the burst predictor.

Will do 

[Mika Köching]

Hi!

Congrats on the launch first of all!

I've already launched quite a few HY30 balloons. Where did you get the HY50 from? I had to buy a whole carton from Hwoyee.

I think I have a pretty good idea for the important values for the HY30. Cd seems to depend on ascent rate quite heavily.

Burst diameter: 1.5m

Cd: 0.5 (for ascent rate <3m/s), seems to be quite a bit lower for higher ascent rates. I'd guess it quickly goes up to 0.3 for 0.4m/s ascent rate.

[John Laidler]

I have discovered the HY50 balloon is available from Amazon UK.

https://www.amazon.co.uk/Professional-Meteorological-Entertainment-50g-120cm/dp/B0CTCMKNPR/

John

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[Steve]

Amazing just type in Hwoyee and 50g into Amazon!

At £9.90 for two inc shipping (£4.95 each) its not that dissimilar to the price I would offer them at.  Suggest folk get them that way instead of me stocking them. I'd have to be selling packs of 5 or 10 to make any sense.

Its not until the large sizes do the Amazon prices start to rip you off.

    Steve

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