Scott Penrose


Scott is an expert software developer with over 30 years experience, specialising in education, automation and remote data.

Mmm.... Wave

Wave flying over the Grampians... TODO.

DISCLAIMER: This information is my own. I do not recommend anyone use it without first confirming or cross referencing. Make your own conclusions and remember that you are in charge.


Main Oxygen System

  • Mountain High - MH EDS O2D1

This is a fully automatic pulse oxygen system that works with both cannula and masks.


This is an excellent oxygen delivery device for most situation. It is comfortable - you can leave it on from launch to landing. You really only need to consider a mask if you are going over 17,000'. If you are really going high, you should consider starting with a mask.

One word of warning - don't try and put this on in flight - they are tricky to get over your ears - do it once on the ground, and if you switch to mask, stay on the mask.

Standard Mask

The standard mask that comes with the MH system. It is a good mask and should (in theory, as I am not an expert) give better oxygen flow.

My own feeling though is that it fits a little sloppy and I feel a little uncomfortable with the leaks. Therefore I went on to "Better Oxygen Mask" below.

Better Oxygen Mask

If you are serious about height, safety and oxygen - this is the mask for you. The design allows complete sealing around the edges, so that you are using the valves to breath.

The down side of this mask is that you really can't hear speech through it, like you can with the standard mask. Mountain High sell them with microphones, but they are rather expensive. Adding your own mike is a fairly easy process - just make sure you connect cables that are easy release in case you have to get out in a hurry.

Remember though, this is oxygen, so check which glues you are using, and don't use oil (technically at this concentration it is safe, and it is only the high pressure that is a concern - but better always to be safe).

Backup Oxygen System

I spent a while finding a backup oxygen system. My first choice was the tiny portable system Co-pilot.

Unfortunately the bottles are pre-filled and therefore can not be transported in/out of America (kind of odd really since they are in planes).

Eventually I found the following system:

E-Ox System 36

Not as small, but it provides the features I want and a little longer air supply.

Pulse Oximeter

Clinical Guard

The "Finger Pulse Oximeter OctiveTech 300C" I purchased was only $90, and they have an Australian supplier, so although you get GST on top, it comes in a couple of days.

If I was regularly staying above 15,000 I would consider spending more on a unit with an alarm.

Moving Map GPS

XCSoar - the best glide computer, moving map and friend to glider pilots :-)

Backup GPS

Garmin 12XL.

WARNING: My garmin was working on the ground but failed in flight. I suspect the batteries got cold. You may want to find a way to keep it warm, or use glider battery power.

Working Compass

If you are stuck above cloud, and you know you can fly North or South (i.e. there is no mountain to hit) you can use your Compass to help reduce your chance of coming out upside down.

XXX Link to article.

Turn and Slip Indicator

I have an old Turn and Slip indicator that I have repaired. However it is not fitted yet and once it is I need to really learn to use it and keep up the practice. The trick is how to practice... Best way is flying in cloud, which we can't do in Australia.

Warm Shoes & Thermal Socks

  • Ugg boots
  • Two or three pairs of socks (1 thin, 2 thick)
  • Feet warmer - e.g. hand warmers used by skiers

Video Camera

Sanyo HD 1000.

This is my 3rd video camera and the only one I have liked. Because:

  • Solid state - no moving parts. Previous camera had a hard disk (useless in aviation), previous was tape (not as bad, but they always break).
  • Small - very very small
  • High Definition - I really didn't understand the fuss, and I still don't for DVDs - but for recording it is essential.
  • Lens - this camera has a f-stop of 1.8 - this is excellent for a small camera.


The ultimate glider.... well the ultimate for the price :-) The Cobra really is a beautiful glider.


My wave flights

  • XX of July 2008
    • Location = Grampians (GSC)
    • Duration = X hours
    • Release Height = 5000'
    • Max height = 24,500'
    • Height Gain = 19,500'
    • IGC File = XXX


  • World Record = ?
  • Australian Record = 33,000 (approx) in ACT
  • Victorian Record = 29,000 (approx)

Weather Predictions

What you need for good wave at the Grampians

(much of these numbers and facts need to be reviewed before they are used)

  • Westerly Wind. Grampians are North/South (roughly). South South-West is ideal
  • Strength of Wind - At the top of the Mt William 15K+
  • Wind getting stronger with height
  • Stable air mass - at least in the main wave area
    • This seems to help with the secondary and tertiary wave
    • (IMHO) it makes the primary wave not as high

(Emergency) Procedures

Most of these procedures could be considered emergency, but some are really routine.

Maximum rate of Descent

Most gliders you don't want to descend faster than about 500' per minute (5 knots). This is because there is a gel coat which cools at a different rate to the rest of the fiber glass. I am in the very fortunate position to fly a wooden glider that is covered with 2 pack polyurethane, so I can come down as fast as I like :-)

Many of our height restrictions though, require us to come down in the same spot, and since one circle at those winds could put you 2-5 Kilometers (yep that much) down wind, you can quickly end up out of your allowed area.

My emergency descent:

  • Check no mountains below
  • Wheel down (not only more drag, but turns off the air brakes alarm)
  • Full air brakes
  • 110 Knots flight (my VNE is 130, but I never go over 110 or equiv)
    • My brakes are rated to VNE
    • NOTE: VNE is dependent on height (see note below)

Maximum Speed (Vne)

Indicated air speed (based on Pitot pressure) decreases with height. My glider has the following:

  • Alt (feet) Calculated True Density Ratio Vne (kts)
  • 0 = 120
  • 5000 = 120
  • 10000 = 111
  • 15000 = 103
  • 20000 = 94
  • 25000 = 87
  • 30000 = 79
  • 35000 = 72

Did you know you should have this placarded in the aircraft if you carry oxygen - you do now.

To calculate you do the following:

  • Find out the aircraft Vne
  • Find out what height it was set at. This changes between manufacturers, but is often around 5000'
    • You can then calculate this for 0, or assume, for increased safety, that this is the value at zero feet.
  • Get the relative density ratio for height - e.g.
    • 0 = 1
    • 5000 = 0.86
    • 1000 = 0.74
    • 1500 = 0.63
    • 2000 = 0.53
    • 2500 = 0.45
    • 3000 = 0.37
    • 3500 = 0.31
  • For each value, multiple the squareroot of the density with the Vne constant.

Loss of Oxygen

This really depends on height.

  • <10,000' - no problem, you are safe at these levels
  • 10,000 - 18,000 - pull out the breaks and come down fairly fast
  • >18,000 - The descent time, even at about 10 knots down is longer than you have available - so don't go this high, unless you have a backup oxygen system.
  • Descent time at 5 Knots (see Maximum Descent above) calculations: to 10,000
    • 15,000 = 10 minutes
    • 20,000 = 20 minutes
    • 25,000 = 30 minutes
    • 30,000 = 40 minutes
    • 35,000 = 50 minutes
  • Descent time at 15 Knots (emergency speed) - be careful not to exceed Vne (calculated): to 10,000
    • 15,000 = 4 minutes
    • 20,000 = 7 minutes
    • 25,000 = 10 minutes
    • 30,000 = 14 minutes
    • 35,000 = 17 minutes

Above 30,000 you consume 3 litres of oxygen per minute. Therefore my emergency tank does about 12 minutes. Therefore I need to be descending at about 20 knots from 35,000 feet ! Think about not having an emergency system...

Stuck Above Cloud


  • Aviate, navigate, communicate
  • Think about clouds first - you don't want to descend through cloud
  • Think about terrain - if you do have to descend through cloud, what is the terrain - is there a mountain
  • Think about the tiger country - you are probably flying near mountains - consider moving away before descending
  • Inform your crew of your moves, and your position before you try going through cloud
  • If you can see a good paddock to land, you no longer have a problem, but don't forget your paddock checks, and don't forget you are probably flying in pretty strong wind - not one suitable for down wind or cross wind landings.

Approval above FL245

Above FL (Flight Level) 245 - or 24,500' above sea level at standard pressure (XXX) is controlled airspace in all of Australia. Therefore to fly above you would normally require a Transponder and approval from flight control. However we are very lucky to have approval at Canbera and Grampians. NOTE: You must have approval by the Grampian Soaring Club (via training and log book endorsement) before you can use this approval.

My Grampaans Cheat Sheet


NOTE: Links to GSC PDFs

  • Gliding