Tuesday, January 8, 2019

Adventure with Green Hornet Electric Starter

Now that I keep acquiring more ½ A glow engines to power free flight and control line model airplanes, I decided an investment in a ½ A glow starter might be wise. Besides the starter I ordered a couple of new glow clips that are like a clothespin and some metal tanks for control line from Brodak. Last evening I was anxious to try the starter out on an AME .049 that had only been run once before. This time I used a Red Cap bladder cut in half because I did not need the larger capacity.

AME .049 Did not Run Well on Suction Feed

First thing I notice was the Hornet starter turns the .049 engine over really fast. Pushing it into the prop nut the prop came lose sending the nut, shaft, and propeller shooting across my messy basement. Luckily I found everything, this time I really tightened it. Yet it kept coming loose. Now I think it had something to do with the fit of the drive washer. After many times of tightening it stayed tight.

Starter Cone on Hornet 1/2 A Starter

As I had found out from questions after the first time running this engine, it does need to run on pressure. I did not want to run it for long as this was in my basement but I could tell that it was not having trouble with fuel suction as it did without pressure. I did not put a tach on it but it sounded like it was turning up pretty good. This is with a Cox 5x3 propeller; I have on order the APC props that people recommend for this engine. The new glow clip worked much better than using a Cox clip.

Bolt Ran into an Obstruction

After some frustration I was pretty happy that I will be able to start and run this engine without much trouble. As I put stuff it away I notice the aluminum cone on the starter was loose, there was a hole for a set screw but I could not see anything in it. I found a bolt that fit the hole and the threads matched perfectly. It would turn easily but about ¼” in it would stop; now I am worried I broke off a screw inside. Then it dawned on me that the set screw might use an allen wrench to tighten. Sure enough I found the correct size and was able to loosen the set screw and re-tighten the aluminum cone. 

Bringing the Set Screw Out

It appears to me that having the acorn nut used with an electric starter come loose is more of an issue than when I flew glow RC using a plastic spinner years ago. I am afraid if I tighten too tight something could break or strip out. The only prop nut I had for my Witch Hawk 500 came off at the Nats and luckily I found it in the grass. Any suggestions on this are Welcome.

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

Friday, January 4, 2019

Electric Free Flight STRIX Timer #2

I have been having so much fun experimenting with electric free flights using the cheap STRIX motor timer and a 7 mm coreless motor. It will only run up to 10 seconds but that gives you a real good view of how the airplane is flying. You can really notice the slightest stall or if it is turning too tight. Making tiny adjustments to get the climb and glide paths just right can make a huge difference in the height of the climb and length of the glide.











This winter I finished a new plane for the electric combo a Sig Cub which looks to fly really well but I have been hesitant to make longer flights with it on the hard surfaces. Instead I have been flying a plane I made up from wing and tail of Flying Aces Moth, which is rather beat-up anyways. The wing is angled giving it too much stab tilt but I just do not seem to get around to fix it.



Sig Cub over Snow




The optimum size appears to be about 24" wingspan. Joshua Finn experimented with a plane using STRIX timer that appeared to be around that size. He even tried using the 8.5 mm motor used in E20 planes but found the battery was out of charge real fast. It would be fun to try a geared propeller too and see if the climb improves.


AMA Maxi Jr Electric


Dog Retrieved the Plane and this was the only Damage


One session flying the FA Moth type plane I had it in lift for a time and was happy it didn't fly any better. Recent flights have been from a frozen lake which gives a huge area to fly from but a crash into the bare ice would not be good. At some point I would like to design my own plane for the electric combo or maybe a couple planes with one using foam sheet.

The timer is now being sold for $5.99 https://www.banggood.com/STRIX-3_7V-1S-Free-Flight-Motor-Timer-For-6mm-7mm-Motor-p-1363923.html?akmClientCountry=America&cur_warehouse=CN 

Joshua Finn video on STRIX timer    https://youtu.be/kBThvOBYUzc 

First article
https://scienceguyorg.blogspot.com/2018/10/experiments-with-strix-free-flight.html

Bill Kuhl

I had much longer flights than this one but this is close.