New email address 23 December 2023:
borgeltinstruments@gmail.com
Due to ongoing issues with our ISP, please use the above address
and/or
instrumentguy48@gmail.com
Please also copy to mborgelt@borgeltinstruments.com
Notice 15th December 2023
There is uncertainty about the email address as our provider (Internode) has decided to go out of the email and web hosting business.
You may use the following alternate email address until notification that our usual mborgelt@borgeltinstruments.com is working:
instrumentguy48@ gmail.com
Please copy also to mborgelt@borgeltinstruments.com
This should all be fixed by New Year.
————————————————————————————————————————————————
How Dynamis Works 15th December 2023
Dynamis development was a long process. From 1984 until now, when we have a stable, solid, reliable Total Energy variometer system which is insensitive to the horizontal gusts in the atmosphere which make traditional pressure based TE varios so difficult and annoying to use.
Read about it below and in Articles
Short Version – long, complete version appears in “Articles”
Traditionally, Total Energy systems in gliders work by measuring the rate of change of airspeed as measured by the pitot – static pressure difference when the pilot pulls or pushes on the stick to lose or gain speed. The rate of change of airspeed depends on the steepness of the angle of the glider trajectory through which the pilot has manoeuvred the glider.
The total energy compensation signal is then given by rate of change of airspeed multiplied by the instantaneous airspeed. However when the glider at steady speed meets a horizontal gradient in the air (aka “horizontal gust”), not at all unusual when flying in a convective atmosphere, a false compensation signal will be generated which appears on the variometer, even though the pilot has not altered the glider flightpath. These signals are of about the same magnitude as the vertical changes (thermals and sink) encountered and are of approximately the same rates of onset and decay resulting in the desired vertical changes shown on the variometer being mixed with a lot of misleading and useless indications from horizontal gradients encountered.
The result is distrust in the variometer indications and a high and tiring workload as the pilot tries to decide whether the indication is due to a thermal or a horizontal gust. It has long been desired that the effects of the horizontal gusts be greatly reduced or eliminated.
As the actual airspeed changes in horizontal gusts are generally small it is the rate of change of airspeed, which can be large on gust encounters, causing the false compensation signals.
If we could measure the angle change directly, the compensation signal is the trigonometric sine of the angle change multiplied by instantaneous airspeed. Note that this DOES NOT depend on airspeed measurement directly, so is immune to the effects of the horizontal unsteadiness in the atmosphere.
Fortunately, with modern technology, it is now possible at realistic cost and power consumption to directly measure the change in angle to the horizon of the glider trajectory.
By using two GNSS (Global Navigation Satellite System) receivers (or one which is essentially two in one package) of the right type we can directly measure the pitch and heading to better than 0.1 degrees in a completely stable manner, directly oriented to the Earth horizontal plane, as well as horizontal and vertical velocities relative to the Earth.
Some other simple sensors are required but the system depends on direct measurement and does not depend on exotic mathematics or assumptions about likely glider or airmass motion.
As a result the variometer indication is MUCH steadier yet very fast in response and responds only to changes in vertical motion of the air while achieving essentially perfect total energy.
Only ONE pointer is required as the indication is so solid and reliable.
The Dynamis variometer information is also used in the Relative Netto and speed command calculations making both indications FAR more steady and useful. 2D wind information is also continuously provided.
————————————————————————————————————————————————
4th December 2023
Here is a comparison of the old 1/4″ TE probe end vs our new, low drag MiniTE probe.
The drag reduction is obvious.
The whole probe with machined end fitting for 8mm socket on fin and carbon fiber shaft. Supplied fully assembled in shipping tube.
Fuselage mount type or different end fitting diameters are available to special order.