Scienceguyorg Ramblings: Bad Axe Embryo

Tuesday, March 7, 2017

Bad Axe Embryo – Thermals Do Not Care

I am less than pleased with myself in the construction and covering job on the Bad Axe embryo class rubber free flight from Volare Products. In no way can I blame the short kit or the plans, some of the problems I believe is in wood I selected for stringers in constructing this model. The Bad Axe embryo won the Embryo Event at the 2016 Outdoor Nationals Free Flight Contest in Muncie Indiana for George Bredehoft. I was at that contest and met George in person for the first time. I took a picture of his Bad Axe while he was winding but somehow missed the flight.

Bad Axe Embryo

Thermals do not care what an airplane looks like is what a couple of people told me when I mentioned my less than stellar covering job. Now I have built small rubber models before and did a pretty good job including two embryo models, the Peck Prairie Bird and the Volare Sky Rocket and the covering went on fairly well. These were full kits that included all wood. Another similar sized model I built was a Herr Champ that unfortunately included stringer wood that was too heavy, the covering went on fine but the model barely flew.

Picture Does Not Really Show Bad Fuselage

When I thought about building the Bad Axe I wanted to keep it light so I ordered some really light 1/16” square stock. When I built the fuselage the outside stringers just did not bend evenly and by the time it was constructed it had this wavy look to it if you looked closely down the sides. Various times the stringers would break on me so I doubled the 1/16” stringers in the front of the fuselage. In doing some research I found some other people had trouble with the pre-cut 1/16” balsa. Bob Clements gave me a suggestion of a business that sold some good pre-cut balsa, Hobby Specialties I will have to check them out in the future.

George's Nats Winning Bad Axe

Covering the Bad Axe I started with the tail surfaces, I was afraid the stabilizer would warp so I covered that rather loose and kept it pinned down while spraying on clear Krylon. To adhere the tissue I used the UHU gluestick for the first time which many modelers use. It is not available locally so I ordered it through Amazon and it took a month to come from Thailand. Then I found out George sells it through Volare. This gluestick seemed to apply smoother than some other brands I have tried. The wing I did water shrink but pinned it down. It came out fairly well using some heat while shrinking. I tried mixing rubbing alcohol with water for the shrinking which should slow down the shrinking process. The fuselage I could not really get in a jig and this gave me fits, several places I cut out sections of tissue where it wrinkled and tried again but still not much better.

Could not get Wrinkles Out

Even though the fuselage has some uneven bends in it I think it ends up fairly straight back at the tail surfaces. I added a fuse DT system with the front of the wing raising up. On my Guillow’s Lancer I had this type of DT and it appears to work pretty well.

It has been extremely windy recently but I hope to get a chance to fly the Bad Axe on the first calm day. Included below is an extensive listing of resources including articles on covering with tissue.

Update 3-9-2017