Thursday, March 23, 2017

Polecat X – P30 Build Report

This is my second P30 rubber free flight model, the first being the NJAPF design by Al Lidberg. My first P30 sat in my basement a long time before test flights and then last year I installed the DT system and flew it in contests.  For my skill level it did well and at the last contest I thought I might never see it again because it was circling ever higher far downwind.  It did come down and Gary Oakins found it, but with a stab DT I worry if another time it might be miles away. 


Polecat X P30



NJAPF First P30


Don DeLoach was running a special if you ordered multiple plans there was a discount so I ordered the Pearl e202 E36 and Polecat X plans with short kits.  I flew the Pearl E36 a good deal last year and learned much about e36, this year I wanted to get the Polecat X flying.  There was so much different about the constructions of the Polecat X than the NJAPF so I asked a lot of questions online. First I had to order carbon strips that reinforce the wing, ¼ mil Mylar covering, and picked up Balsarite at local hobby shop to stick the Mylar down. Wing and stab construction went well but then I built my first round tube fuselage by wrapping balsa around a pipe, that went alright too. Covering with the Mylar went better than I thought it might, some Design Master spray paint gives it some color. 


Wing Before Carbon Strips


Stab With Carbon Strips


As I completed each major structure I weighed it and then again after covering to compare with the suggested weights on the plan, my weights were close but slightly higher. This is really a detailed plan which I appreciate; no other instructions are really needed.  The contest wins for this model are really impressive and it is a plane that has been refined over many years of contest flying. With the rearhook is in the very back of the fuselage and with a light airframe a really long rubber motor can be used to get a slower climbing motor run that lasts a long time.  It is my understanding it could be possible to get a 2 minute max with the rubber still turning the propeller.


DT Only might not be available
Another new item I wanted to try was the BSD Micro electronic “DT Only”. The weight without battery should only be around 1.5 grams, the battery is a single cell lipo as small as 35 mah.  After trying some ideas of mine that did not work for the DT parts on the plane, I used the method shown on the plan when using a viscous DT timer.  The tiny servo built into the electronic unit does not have a lot of force so having the proper linkage is essential. Adjustment for DT time is done with a really tiny potentiometer that is rather fragile.  When you have it set correctly the DT time should be completely consistent in all conditions. This is the first time I am using the pop off wing idea in the DT which is said to be the only sure way to bring a P30 down from a strong thermal. 


Gizmo Geezer on Test Stand


Again I am using the Gizmo Geezer propeller system, I had installed this on my NJAPF p30 the end of last season and it worked well. With the Gizmo Geezer a certain amount of tension is held in the rubber so braiding is not needed and it has a good working freewheeling system. A couple of people had a concern with all the downthrust called for on the plan if the rear of the Gizmo Geezer might touch the top of the fuselage, I still need to test this.

Now if the weather would cooperate, I could try some test flights.

Update 3/29/2017 - I tried test flights on 150 turns, flies well.


Polecat X 150 hand winds


Bill Kuhl
http://www.ideas-inspire.com

Related Links

http://www.pearlfreeflight.com/Buy.html  Pearl Free Flight website

http://volareproducts.com/BUY/index.php?main_page=index&cPath=56_42_80
Gizmo Geezer Propellers

http://www.bsdmicrorc.com/index.php  DT Only timer does not appear to be on the website any longer.


http://scienceguyorg.blogspot.com/2016/09/gizmo-geezer-review-part-1.html  Gizmo Geezer Review Part #1

http://scienceguyorg.blogspot.com/2016/10/flying-with-gizmo-geezer.html  Flying With the Gizmo Geezer


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