2016 Lessons Learned #1 – Power and Glide Trimming

I started flying Free Flight in the mid ’80s – so I’ve been doing this a long time.  Still, it amazes me what I don’t know; I still am learning things.  Another surprise is why it takes so long for some of this stuff to sink in to my thick skull.  Here are some of the things that I have discovered this year.  Maybe “discovered” is the wrong word, but I think that I am finally getting them to stick and become part of my routine.

Cruise, Glide, Balance, Thrust
Everyone “knows” that you need to trim a plane.  You know, get that proper turn, climb-out, and glide for the best duration.  On three different models at the last Cloudbusters Outdoor contest of the year, I implemented a routine that improved each model’s flight characteristics.  Two models were new and one was a year old.

All year long, I’ve been struggling with my Elmendorf Special.  It is a 16″ wingspan race plane and “should” have been a reliable flyer, as its heritage is from the very popular Tom Nallen (I) “Jackrabbit” plan.  I never expected it to be a Nationals competitor, but I wanted it to be a strong contender at the local events.  Make no mistake, I won, placed or showed at nearly every race, but something just wasn’t right.  Mainly, the climb-out was smooth, but the glide was not stable, porpoising, and such – there was porpoising even in the later parts of the cruise and downthrust wasn’t helping.  It was getting to the point that launches were becoming risky because they were very flat.

In the process of trimming my two new planes, the Guillows #905 P-51 and the Shaft stick model, I had what I will call an epiphany.  I always glide-trim under light power, a couple hundred winds.  In my opinion, this compensates for the drag of a freewheeling prop and gets the plane to a flying speed before the turns are gone and we can watch the glide.  Once I find a good balance to get a respectable glide, I gradually increase the turns and adjust the thrust to keep the flight pattern I want – all standard stuff.  But here is what I did that worked on these two planes and fixed my Elmendorf Special:

I’ve been wracking my brain over this porpoising – that means add nose weight – but this would ruin the trim on my planes as they have flat climb-outs now.  HERE IT IS:  if you add nose weight, take out downthrust AT THE SAME TIME.  I repeatedly did this over the course of several flights and it really stabilized my planes.  Add a bit of weight, take out down thrust; add weight, take out down thrust – consider it ONE change (not two).  Eventually, my models had reliable power, cruises, AND stable glides.

Stay tuned for more 2016 Lessons Learned.

elmendorftrim

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One Response to 2016 Lessons Learned #1 – Power and Glide Trimming

  1. Colin Miller says:

    Great bit of advice, l have always had that problem too!

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