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Outdoor Free Flight Forum => Free Flight Scale => Topic started by: DHfan on January 10, 2019, 06:37:42 PM



Title: Suggestions for rubber Power Trimming literature/guides?
Post by: DHfan on January 10, 2019, 06:37:42 PM
My biggest issue is trimming under power and I have not been able to get the hang of it.  Any suggestions on guides to troubleshoot power trimming symptoms? Change of effects as winds increase and approach max, thrust line cause and effect (past the obvious), differences in trends between high and low wing designs, etc. Rubber power specifically. I realize there is a lot of variation between models, but there are general underlying principles.  I have tried building test models to experiment with (it helped) but typically before I have collecting enough data on a design the repairs have changed the configuration enough to make the trends questionable, or at least they don't hold for the next design.
Thanks.
Mike


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: ZK-AUD on January 10, 2019, 07:11:13 PM
The bible for the basic principles is probably Don Ross' book which is pretty widely available.  That and to get with an active local club for some hands-on tutoring.


  https://www.bookdepository.com/Rubber-Powered-Model-Airplanes-Don-Ross/9780938716198?redirected=true&utm_medium=Google&utm_campaign=Base3&utm_source=NZ&utm_content=Rubber-Powered-Model-Airplanes&selectCurrency=NZD&w=AF7CAU9SXJZKQRA8039V&pdg=pla-309308959159:kwd-309308959159:cmp-947803846:adg-45233890737:crv-225027758853:pid-9780938716198:dev-c&gclid=EAIaIQobChMIpLDX6rfk3wIV0CMrCh0HxAKIEAYYASABEgJVP_D_BwE


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: vtdiy on January 10, 2019, 08:34:22 PM
....but typically before I have collecting enough data on a design the repairs have changed the configuration enough to make the trends questionable.....

Boy, am I familiar with that.....

Don Ross's book is great, though.

From that book, at least I know what is supposed to be happening, assuming after a power stall the prop hasn't broken, shaft bearing hasn't bent, the nose sticks haven't snapped, I haven't put my finger through the tissue, or the rubber motor hasn't ricocheted through the tail!


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: DHfan on January 10, 2019, 10:46:59 PM
Thanks! I have not looked at Don Ross' book for some time.  I will reread.


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: charlieman on January 11, 2019, 03:23:36 AM
Bill Warner wrote the trim article/trouble shooting page in Model Builder WWII Fighters plans booklet (IIRC, all the plans from that book appear in Gallery).


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: duration on January 11, 2019, 07:26:36 AM
Mike,

The 2018 National Free Flight Society Symposium Report (Sympo) has an excellent article by Don DeLoach on scale models. It focuses on matching rubber to model. Perhaps the most important point Don makes is that torque, not turns, is what matters in trimming and flying rubber scale models. (Any rubber model for that matter.)

The Sympo and other useful FF books and plans can be ordered from the NFFS store. www.freeflight.org

If you are not a NFFS member you may not be aware of the NFFS Digest magazine, edited by Don. It usually features two or three full-size scale plans in each issue.

Louis


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: DHfan on January 11, 2019, 06:19:33 PM
Charlie I will take a look at the MB WWII book, another I have not looked at in some time.

Louis, I had not seen the 2018 Symposium Report.  Thanks for the reference!

Thank you both.

Mike


Title: Re: Suggestions for rubber Power Trimming literature/guides?
Post by: Walt on January 11, 2019, 11:14:47 PM
You may want to read the book: “making scale models fly” by William McCombs.  He does an excellent job of reviewing stability and power issues, including a diagnostic checklist that is very useful.
Wally