Re: Increasing duration in F1D - prop settings and back-off

From: John Kagan <john_kagan_at_hotmail.com>
Date: Tue, 20 Mar 2012 22:27:09 -0000

That's good info, Dezso. As I interpret it, you are graphing the number of seconds it takes for a given number of prop revolutions.

I chart the revolutions per minute, so our graphs are vertical mirror images of each other - it took me a minute to figure out why yours didn't look familiar :)

--- In Indoor_Construction_at_yahoogroups.com, Dezso Orsovai <orsid48@...> wrote:
>
> Hi Tapio,
> for example...
> you can change the data in the table. 
>
>  
> Dezso Orsovai
>
>
> ________________________________
> From: John Kagan <john_kagan_at_...>
> To: Indoor_Construction_at_yahoogroups.com
> Sent: Monday, March 19, 2012 4:35 AM
> Subject: [Indoor_Construction] Re: Increasing duration in F1D - prop settings and back-off
>
>
>  
> Hi Tapio,
>
> Launching with no backoff is a good goal. There is a lot of energy in those top end turns - much more than cruise or descent turns. You want all of that energy. Energy = time :)
>
> I recommend charting the RPM during a flight. That will give you a clear picture of when the prop starts and finishes changing, and how much it changes. This is a more accurate method than watching the climb - IMO.
>
> --- In Indoor_Construction_at_yahoogroups.com, Tapio Linkosalo <tapio.linkosalo@> wrote:
> >
> >
> > Last night when making motors (for F1B...) my thoughts turned to
> > Belgrade, again. Started to wonder what to do to climb up the ladder of
> > duration (I'm currently at 26 mins, so next target should be closer to
> > 30...)
> >
> > Comparing my flight profile to the one that John was flying in 2010, I
> > was surprised to see him taking almost 20 minutes to climb to the
> > ceiling. My model was at the apex of the flight profile in 10 mins... So
> > obviously this is where the missing flight time lures. One thing that I
> > need to fix for next summer is to modify my VP's to take higher max
> > pitch, currently I'm against the top stop (cannot adjust any further),
> > and need to take backoff to avoid hitting the ceiling.
> >
> > So this is the first question: should I aim to fly with no backoff at
> > all, and just add the max pitch to control the amount of the climb?
> >
> > Second, my props use a "soft" spring with multiple turns. Thanks to very
> > informative discussion with the Brits last summer, I now understand that
> > this kind of spring works with a rapid movement from high pitch to low,
> > and indeed this was showing in my flight profile last summer: after the
> > apex at 10 mins, the model started descending, until at around 14 mins
> > the pitch changed, resulting in a shallow second climb and then cruising
> > down for the rest of the flight. Maybe a "harder" spring of fewer turns
> > would enable similar action as Treger was showing, with a long cruise
> > not changing much altitude throughout the middle parts of the flight? I
> > suppose this would, however, make the adjustment of the spring
> > pre-tension much more sensitive than with a softer spring?
> >
> >
> >
> > -Tapio-
> >
>
Received on Tue Mar 20 2012 - 15:27:12 CET