- Category: Archive 2015
- Hits: 450
- On the Database
- How to D/T a Haggis...
- ...With your Magic Timer
- Observations from last weekend
- And the Turks too
On the Database
From: Ian Kaynes
FAI Sporting Licence Database
As a clarification to your good summary of the subject: The National Aero
Club enters their licences direct on to the FAI database and there is no fee
associated with this. The licence fees - which vary wildly between different
countries - are retained in the issuing country. The overall FAI national
membership fees are set by other factors, such as how many air sport
participants there are in the country.
There is a facility for championships organisers to make a bulk check of
their entry against the database. As yet they have not extended this option
to World Cup coordinators. When they eventually do this I will be checking
my World Cup database against the licences (but currently I would not
consider manually entering 1000 names one by one!)
What Constritutes a DT ? or How to D/T your Haggis
Whilst scanning your fine organ I come across comments concerning DT
These of course have been successfully used for many years where small
sites or a wind direction towards obstacles have meant having to loose a
model to win an event - and they work well, even in Scotland. But what
constitutes a DT; if it is just the irreversible angular change of the
tailplane (or wing) incidence then how much (or little) angle do you
have to set ?
We all know that models that have a sticking DT (ie not full angle
occurs) can just loop and go up in lift - is that a legitimate DT if set
deliberately ? We also need to consider what the old-and-sneaky
aeromodeller might do to maximise his DT time before we use DT flyoffs
as a matter of course.
If Biggles was still with us he will be sketching some ideas that would
confound the rule-makers so we should just be careful of unexpected
With your Magic Timer
With a brief message from our sponsors .....
Some Magic Timers have a park position for the servo after D/T. The timer moves the servo to this position about 3 seconds after D/T. Some canny sportsmen re using this feature to adjust the angle of the stabilizer once D/T'd . The additional movement of the servo after D/T is used to tune (i.e, alter) the length of the line that controls the angle of the stabilizer in the D/T position. So in the past this would be used to increase the angle of the D/T for extreem thermal condition. It appears that there maybe another use for this now.
Speaking of Biggles and D/T, some years back I was interested to note that some of Aerovironment's small fixed wing UAVs used a Free Flight type of D/T to land the craft at the end of the mission. Clearly the easiest way to land the craft safely in rough terrain.
Observation from last weekend
regarding your note on SEN about Bulgarian/Hungarian style flyoffs....
I was present at Tapolca (HUN) last weekend and can report what I saw.
In F1C there were 3 in flyoff and all using e-timer. They had the DT time set to 120" that was checked by the timekeepers, and they clocked they flight duration from model release to landing.
The same happened in the other classes, maybe with different DT times.
And the Turks too
From: Didier Chevenard
We found the same issue at the last Turquish cup in Vize (June 6th) and the organizers decided to time the model down after 1mn DT for the fly-off (the Bulgarian way?). I believe that they did the same in Ukraine the following week!
Given the altitudes gained the models are already very far away with a wind around 10 m/s!
Now we will optimize the sink rate after DT...(ah!ah!ah!).
With a mechanical timer and its variability it could have been difficult to set it, especially after round flights DTed at 90s!
Much easier with electronics!
Nevertheless it is a good system because the Fly Off was scheduled the following morning, expecting that the wind would slow down, but it did not!!!