SEN issue 1096 - 23 May 2007
- Details
- Category: Archive 2007
- Hits: 957
- What your Frequency ?
- A Redneck trims a F1B
- That F1J Engine - 1
- That F1J Engine - 2
What your Frequency ?
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Right Honourable SCAT,
Re: SEN 1093 and the comment on RCDT. Yes, the Multiclass (Danish)
RCDT system does use 35MHz which is a legal model aircraft frequency in
most of Europe but not the US. Is the Airtek system which I note uses a
much higher frequency also legal in the UK/Europe ? I suspect there is
no universal frequency that can be used for RCDT over the whole of the
aeromodelling world unless the frequency is switchable.
Can anyone comment ?
EoB
EoB - there are several issues.
Firstly in every country our National associations have spent much time and effort negotiating R/C frequencies with the appropriate local authorities. On R/C flying fields there are procedures for safety etc for the use of these frequencies. For this reason we should not attempt to use those used by R/C, except for perhaps the new spread spectrum equipment.
There are a number of very common frequencies that do not require a license. Some of these are pretty much universal. Some countries may require the equipment to be type approved even though not license is needed. This can be obtained by using ready made type approved modules. The license free transmission may be subject to rules such as level of output.
A Redneck Trims a F1B - From Yahoo FFML
Posted by: "Tapio Linkosalo" This email address is being protected from spambots. You need JavaScript enabled to view it. linkosal
Mon May 21, 2007 1:18 pm (PST)
I've been trying to fing a good location of CG on a new wakefield model.
Found out that my models with Bob White airfoil seem to work ok with a
relatively forward CG, but that just made me wonder how the CG location
affects thermal behaviour. I am under the impression, that models with a
rearward CG seem to be unsensitive to lift, flying through it unaffected,
so can I conclude that a forward CG then makes models more sensitive to
lift? Or would the tendency to raise nose when flying into lift rather
throw them out of the lift?
-Tapio-
Re: CG, longitudinal stability and thermal sensitivity?
Posted by: "Dean McGinnes" This email address is being protected from spambots. You need JavaScript enabled to view it. flydean1
Mon May 21, 2007 4:42 pm (PST)
I am probably less qualified that most on this list to comment, but let me
put my Redneck Flight Instructor hat on and try.
With reference to the above, I don't think it matters much. A model in lift
will go up regardless of the CG location. What we are dealing with here is
the pitch stability characteristics of a particular model and how it behaves
in the air. The rear CG/low decalage model will go straighter, and "appear"
to fly along unaffected. The forward CG/high decalage model will be more
"loopy" and will bounce around more.
Either will respond to rising air. The more rearward we can move the CG the
less decalage is required and the less overall trim drag results. All being
equal, the rear CG model will glide more efficiently, and will fly better in
lifting air. However, that said, sadly, all things are not equal, and the
same model will recover badly from upsets, which are found in thermals.
This could explain how some models seem to be "thrown" out of thermals. It
could just be a case of insufficient pitch stability due to a rearward CG
and less decalage. The forward CG model will have more total drag, and be
less efficient, but will handle the bumps better.
Name your own poison. :-)
What I would like to see here, is a discussion on trim setups that will
enable a model to "center" or "core" in a thermal.
Dean McGinnes
Lakeland, Florida
That F1J Engine - 1
From: This email address is being protected from spambots. You need JavaScript enabled to view it.
F engine for F1J/F1P:
Try here:
http://www.gregorie.org/freeflight/f1j/f_engines/price_list.html
Bob Beecroft
That F1J Engine - 2 - RUSENGINES.RU - Company «Cyclon» makes engines for airmodelling sports.
From:This email address is being protected from spambots. You need JavaScript enabled to view it.
F1J engines from Russia.
http://www.rusengines.ru/?lang=en
On this sites are a reports from competitions too.
I flew classic no geared VE engine on the Srem cup.
...........................
Roger Morrell