Amateur Radio on Balloons - Ilmari 2003 Balloon
 

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SuperIlmari 2003

The Ilmari Project is not a Viestikallio Project, this just happened to be a place where we could host these web-pages...

Ilmari Balloon

Parachute:

Parachute construction, and doubly-redundant balloon release:

Parachute Cutoff-3

Chute material cutout guestimates

System descend rate can be estimated from same drag calculations as are used for Ascend rate. The "Cd" is likely a bit larger, perhaps "1.3" ?

Flight plan:

Two possibilities:

  • Up with one balloon at a sedate (or nominal) rate → burst → down
  • Up with a Balloon Cluster:
    • Topmost is lonely big balloon giving small positive boyancy (2-3 newtons)
    • Below that one or more smaller standard sounding balloons attached to same lift ring.
    End result is accelerate raise, until "booster balloons" burst, and primary balloon's lonely ascend begins.

Flight-Plan-1


We got balloons:

We received a donation of five Totex TX1200 balloons:

We also got data about TA1200 ballons from Japan. According to company sales representative, they are otherwise identical to TX1200, but temperature specification is merely to -70°C, where TX1200 has it at -80°C. totex-data-1, totex-data-2, totex-data-3.

Balloons with same name are at: Kaymont

Balloon "Burst Pressure" is the pressure differential in between its inside and outside. The balloon will have its maximum size, when that pressure differential is achieved.


Balloon Ascend rate

Ref: [W0RPK].
Ref: Geocities, CapeCanaveral: Ideal Gas Equations (Air density calculation is done wrong: both oxygen and nitrogen are calculated as if atomaric, instead of molecular! Markup tells about molecules all the time, just values are wrong.)

After a bit of algebra, we get:

                   /--------------------
                  /  LIFT - WEIGHT
  AscentRate =   / ---------------------
                / 0.5 Cd pi r² ρ(Air)
               v
Where:
= Balloon ascending cross-section radius (meters);
0.90 m for TX1200
Cd = Ball drag coefficient, circa 0.35 [Drag Coefficients]
LIFT = Gross lift (Newtons)
WEIGHT = Total system weight (Newtons)
ρ(Air) = 1.225 kg/m³ @ h = 0 km, 0°C
AscendRate   Ascend rate in meters per second.

There is a relationship with altitude, balloon volume, balloon cross-section, and local air-density which together essentially cancel changes in each other. Balloon internal temperature follows external by a small delay, which means that internal density does not always match external one. Balloon envelope does compress internal gas, but that pressure effect does not exceed balloon's burst-pressure, and being about half of that limit value for most of the time.

With gas density data forther down at this page:

Lift forces per m³ at h=0, T=0°C for:

  He  ~ 10.3 Newtons
  H   ~ 11.1 Newtons

For Kaymont KCI TX1200 balloons those are:

  He  ~  30.8 Newtons
  H   ~  33.4 Newtons

That is, Hydrogen has merely about 8% better lift, on the other hand, that 0.8 Newton difference per m³ may be important... (For Kaymont KCI TX1200 balloon that means (perhaps) 2.6 Newtons, or weight of 0.265 kg mass..)

Listed gross-lift is 33.7 Newtons.

Varying Net Lift ( = LIFT - WEIGHT ), and fixing r=0.90m:

  Net Lift     AscendRate   AscendRate
    1 N         1.35 m/s      81 m/min
    2 N         1.91 m/s     115 m/min
    3 N         2.35 m/s     141 m/min
    5 N         3.03 m/s     182 m/min
    8 N         3.83 m/s     230 m/min
   11 N         4.50 m/s     270 m/min
   15 N         5.24 m/s     314 m/min
   20 N         6.06 m/s     363 m/min
   30 N         7.42 m/s     445 m/min

From this last table we see, that balloon raise speed can not be lowered arbitrarily small below circa 100 m/min. Also speeding up is very challenging!

Ascend speed of 150 m/min for 20-35 km ascend takes about 100 minutes.

How to raise as soon as possible to 15-20 km ?   An extra standard sounding balloon could offer extra 10 Newtons lift → 15 N lift would give 300-320 m/min, which to 13 km takes 40-45 minutes. To 20 km it would take 60-70 minutes.

Longest possible flight-time would be raising up as slow as possible, e.g. at 100-150 m/min: 3.9-5.8 hours.


System Descend Rate

With same equations as above, with slightly different way of calculation:

  Fmass = m * g

  Fmass = FDrag

After a bit of algebra, we get:


  DragAreaSum =  Cd_1 Ax_1  +  Cd_2 Ax_2 + ...


                   /---------------------
                  /       2  m  g
  DescendRate =  / ----------------------
                / ρ(Air)  DragAreaSumm
               v
Where:
= Descending system total mass
= Local gravity constant: 9.81 m/s²
Cd_* = Descending sub-compoents (box, parachute) individual Drag Coefficients [Drag Coefficients]
Ax_* = Descending sub-compoents (box, parachute) individual projected cross-section areas
ρ(Air) = 1.225 kg/m³ @ h = 0 km, 0°C
DescendRate   Descend rate in meters per second.
DragAreaSum   Sum of sub-component products:   Cd_* * Ax_*  


FUTHER ENGLISH TRANSLATIONS IF NEED ARISES


Muuta pientä: Korkeuspaineen kaava:

Likiarvo:

p(h) = 0.5(h/5.5)
Jossa: "p" = paine bareina, "h" korkeus kilometrejä.

Tiheys, paine ja lämpötila:

pV = nRT

Jossa:

pPaine
VTilavuus
nmoolimäärä
RRydberg vakio (8.31451 J/mol/kg)
TLämpötila (K)

Kaasutiheyksiä:

Paineessa 1 Bar, lämpötilassa 273 K:

Ilma1.29 kg/m³
Vety0.09 kg/m³
Helium0.18 kg/m³

AGA dataa: Paineessa 0.98 Bar, lämpötilassa 288 K:

Ilma1.19 kg/m³
Vety0.083 kg/m³
Helium0.164 kg/m³


Nosteesta

Noste eri korkeuksilla riippuu ideaalikaasuyhtälön mukaan:

  • Tilavuus (V) vakiona
  • Rydberg vakio (R)
  • Paine (p(h)) likiarvokaavasta yllä
  • Lämpötila (T) pinnassa 273+0 K, korkealla 273-60 K.
  • moolimäärä (n) tuntematon

Jätetään korkeusriippumattomat vakiot huomiotta ja tutkitaan vain eräänlaisten "moolimäärää tilavuusyksikössä" lukujen suhteita eri korkeuksilla:

n(h)   =   V   p(h)
R   T(h)

n(h) lukujen suhde eri korkeuksilla skaalaa suoraan nostetta maan pinnan tasolla.

Ylipaineettoman kaasupallon noste (kiloja/m³) korkeuden suhteen:

ILMARI 2003: 0-paine-ero pallon nostokyky
Korkeus (km) Paine (bar) Lämpötila (K) "mol/V" (n) n(0) / n(h) Noste H kg/m³ Noste He kg/m³
n = p/T
0 1.0000 273 0.0036630 1.00 1.281 1.272
5 0.5325 263 0.0020248 1.81 0.708 0.703
10 0.2836 213 0.0013314 2.75 0.466 0.462
15 0.1510 213 0.0007090 5.17 0.248 0.246
20 0.0804 213 0.0003775 9.70 0.132 0.131
25 0.0428 213 0.0002010 18.22 0.070 0.070
30 0.0228 213 0.0001071 34.21 0.037 0.037
35 0.0121 213 0.0000570 64.25 0.020 0.020
40 0.0065 213 0.0000304 120.65 0.011 0.011
45 0.0034 213 0.0000162 226.56 0.006 0.006
50 0.0018 213 0.0000086 425.45 0.003 0.003

Yllä olevasta taulukosta näkee, että yli 20 kilometrin korkeuksilla vety ei tuota havaittavaa noste-etua suhteessa heliumiin.

Maksimi nousukorkeus riippuu sitten pallon ja kuorman massasta, sekä pallon tilavuudesta.

Ohessa on laskettu rullalla saatavan muovikalvoputken nostokykyä per metri:

ILMARI 2003: Makkarailmapallo
20 µm polyesteri tai polyeteenikalvo "makkaraputkena" 15 km 20 km 25 km 30 km
Noste kg/m³: 0.248 0.132 0.070 0.037
Litteä leveys (m) Massa/m² (g) Pituus- tilavuus (m³) Pituus- massa (g/m) Netto- noste kg/m Netto- noste kg/m Netto- noste kg/m Netto- noste kg/m
0.5 26.0 0.080 26 -0.006 -0.015 -0.020 -0.023
1.0 26.0 0.318 52 0.027 -0.010 -0.030 -0.040
1.5 26.0 0.716 78 0.100 0.017 -0.028 -0.052
2.0 26.0 1.273 104 0.212 0.064 -0.015 -0.057
3.0 26.0 2.865 156 0.554 0.222 0.045 -0.050
4.0 26.0 5.093 208 1.055 0.464 0.149 -0.020
5.0 26.0 7.958 260 1.714 0.790 0.297 0.034
10.0 26.0 31.831 520.0 7.374 3.682 1.708 0.658
15.0 26.0 71.620 780.0 16.982 8.674 4.233 1.870
20.0 26.0 127.324 1040.0 30.536 15.767 7.873 3.671

Mitään 5m leveää kalvoputkea tuskin löytyy, sellaista voi toki tehdä kuumasaumaamalla.

SAUPLAST Oy tekee std "makkaraputkea" ("letkua") 30µm paksu x 1000mm leveä, 25kg rullina (noin 410m per rulla). Tuo on heidän suurin mallinsa. Rullan hinta noin EUR 50. Neliömetrimassa noin 35 g/m².

Ottamalla 10m pitkä ja 2m leveä "makkaraputki", nolla-paine-ero-pallolla päässee jonnekin 17-20 km korkeuden tietämille. Toisaalta nostetta saa helpohkosti lisää ottamalla rullalta pidemmän makkaran.


Pallolla on pienin pinta-ala tilavuuteensa nähden (ja täten kevein kuori):

ILMARI 2003: Pallo
20 µm polyesteri tai polyeteenikalvo 20 km 25 km 30 km 40 km
Noste kg/m³: 0.132 0.070 0.037 0.011
Halkaisija (m) Massa/m² (g) Tilavuus (m³) Massa (kg) Netto- noste (kg) Netto- noste (kg) Netto- noste (kg) Netto- noste (kg)
1.0 30.0 0.5 0.1 -0.025 -0.058 -0.075 -0.088
2.0 30.0 4.2 0.4 0.176 -0.084 -0.222 -0.331
5.0 30.0 65.4 2.4 6.283 2.225 0.065 -1.636
8.0 30.0 268.1 6.0 29.4 12.7 3.887 -3.083
10.0 30.0 523.6 9.4 59.7 27.2 10.0 -3.665
15.0 30.0 1767.1 21.2 212.1 102.5 44.2 -1.767
17.0 30.0 2572.4 27.2 312.3 152.8 67.9 1.059
20.0 30.0 4188.8 37.7 515.2 255.5 117.3 8.378

Vaisala oy: Joitakin luotainpallojen ominaisuuksia.

Ralph Wallio, W0RPK: Daydreaming of Polyethene

Cluster:

Lentäminen isoilla lateksipalloilla ("EH" tyyppi, 1-2 kg pintanoste), jotka täytetään antamaan lähdössä pienehkön nettonosteen (0.2-0.5 kg, tms) per kappale.

Ryppääseen laitetaan 4-7 palloa.

Tavoitteena nousu korkealle, jossa YKSI pallo ratkeaa, tai irroitetaan. Lopuilla saadaan kelluva tasapaino ratkeamiskorkeuden alapuolella.

Kokonaisuudessan rypäs nostaa pinnassa 1.2-1.5 kertaa enemmän, kuin mitä luotain painaa, mutta pallot ovat paljon pienempiä, kuin mitä normaali yksittäisen pallon lähetys käyttää.

Argentiinalaiset ovat lennättäneet rypäleitä: LW2DTZ Cluster Balloon

Ajatus oman rypäleen rakentamisesta:

Cluster-Balloon

Revisioitu versio rypäleen lennättämisestä, jossa primaaripalloa ei hankaa minkään apupallon naru. Ajatus on, että:

  • pääpallo riittää nostamaan kuormaa hitaasti ylöspäin
  • apupallot ovat pieniä halpoja ylitäytettyjä luotauspalloja, jotka vauhdittavat alkuvaiheen nousua, kunnes ne ratkeavat jossain alempana, esim. 20 km:ssä.

Cluster-Balloon-2

Matti Aarnio <matti.aarnio@zmailer.org>; OH2MQK

 

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