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General control line discussion => Open Forum => Topic started by: Paul Taylor on October 05, 2017, 03:10:15 PM

Title: To add or not to add tip weight?
Post by: Paul Taylor on October 05, 2017, 03:10:15 PM

My Sea Hurricane gets lose at the top of the hour glass.
Reading some of the threads I'm thinking I need to add a little tip weight and maybe move the LO forward?

Aero-LA 46
Plane is 45oz
10/22 GMA
TT 11x4.5 ... swapped to a 11.5x4 APC. Seemed a little better maybe.

Just a thought but maybe we need a section just on trimming. I have been searching and not real successful.

Thanks

Title: Re: To add or not to add tip weight?
Post by: Dan McEntee on October 05, 2017, 08:10:59 PM

  What is lap time?  I have a Sakitumi that is a similar weight, LA.46 and flew it a lot with the APC 11.5-4, 11-4, and 12.25-3.75. It seemed to want to wind up with all of these, and up top tension wasn't the best. I tried the TT-11-4.5  and have been happy since.  I think I have it turning a few more RPM but still in the 5.5 second range and tension is much improved, speed more consistent. I like that plane a lot now. Try the flatter pitched props again with more RPM. If tension is better but lap time too fast, go to two foot longer lines. Search on here or on line for the Paul Walker trimming flow chart that was in Flying Models with the Impact article. Must reading for everyone, even those that only occasionally do a loop or two.
  Type at you later,
  Dan McEntee

Title: Re: To add or not to add tip weight?
Post by: Fred Underwood on October 05, 2017, 08:54:23 PM

Walker trim articles here and into 2016

http://flyinglines.org/archive.15.html

Title: Re: To add or not to add tip weight?
Post by: Paul Taylor on October 05, 2017, 09:25:45 PM

Thanks guys.
Lap times are 5.2 on 58ft lines at 9500.

Will give the trim chart another read. Did not see anything on the flow chart that describes my issue.

Title: Re: To add or not to add tip weight?
Post by: Steve Helmick on October 05, 2017, 09:38:03 PM

Experimenting is the name of the game. Try something, even if it's wrong. Just make sure you can put it back the way it was, in case you decide that was better. You might try moving the CG fore/aft instead (Higley Heavy Hub vs. stock nut/washer) of moving the LO's, because that would be easier to accurately return to original. This would tell you which direction to move the LO's, at minimum.   

Even I would suggest that 58' lines is about 3' (or more) short for a .46, but you should probably fix the problem with those before you use longer ones.  y1 Steve

Title: Re: To add or not to add tip weight?
Post by: Paul Taylor on October 06, 2017, 06:57:53 AM

Thanks guys.

Title: Re: To add or not to add tip weight?
Post by: Joe Gilbert on October 06, 2017, 07:32:00 AM

Paul do something even if it is wrong you will learn from it.

Title: Re: To add or not to add tip weight?
Post by: Dennis Toth on October 06, 2017, 01:24:48 PM

Paul,
5.2 sec lap time on 58' lines is a bit slow. If that is center to center you should be at about 4.85 if eye to eye would be about 60' CtoC then around 4.95. You need to pick up the rpm in either cast, the line tension will improve a lot. I like to fly the 46 size ship on 64' C to C at a lap time of 5.2.

Best,   DennisT