Thursday, June 15, 2017

E36 Free Flight 2017 Progress – Sometimes I go Backwards

If it was too easy it wouldn’t be so darn fun; at least that is how I feel about my faster climbing free flight models.  Adjusting somewhat slower climbing models like my e20 Sky Demon and the electric Sniffer provided me with some challenges but both are adjusted pretty well now but I am still adjusting the power pattern on the e36 Starduster. 

BMJR e36 Starduster

Last weekend I thought the climb looked really good and it was consistent, my attempt at setting 5 second DT did not do as well and the plane hit the ground hard enough to break the fuselage in half. It was a quick repair and it was still climbing in a consistent power pattern. I had originally put a lot of stab tilt in the stab mount thinking it was needed to get left glide. It turns out there was too much left glide so I kept putting shims under the low side. What I had not thought of was this was shimming the front of the stabilizer on both sides creating more positive incidence which gave the plane less climb which is what was needed.

E36 Starduster

With all the shims to get the stab level, the stab platform was only supporting the bottom of the stab in a couple of small spots.  So in my fix up for the next flying session I cut off all the shims and re-glued the stab platform level; it looked much better. I also made a magnetic hatch for the battery compartment.

Stab Tilt Diagram

Shimming to Make Level Again Created Positive Incidence

Stab Level Took Out Positive Incidence

I am slowly learning with any change, start with very short motor run and quick DT.  That is what I did and a good thing, the airplane was doing half a loop after launch and the turn was more to the right.  I tried launching more to the left but it was obvious it was going up too much. I had other things to do but I went flying again later and started shimming the front of the stab, the power pattern was getting better. Finally it dawned on me what was happening and I continued to add more shims. The flights were now very consistent. 

Magnetic Battery Cover

When I got home I put in a permanent shim and also a small shim for the motor. The glide has plenty of left; it is only in power phase that it wants to go right. Next time I will proceed very carefully with the new changes.  The more flying I do with these free flight models the more comfortable I am making trim adjustments and interpreting the  results.  

Bill Kuhl  BMJR Models Starduster e36  Texas Timers  eMAX timer and accessories

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