Flight Times and Strategy

[bjt4888]

So, as Nationals is now complete, here are some details about our flying and our airplane. Hopefully, this info will benefit all teams in their future competitions.

I had three teams in the Michigan States. They finished 1st, 2nd and 3rd in Wright Stuff with flight times of 3:10.5, 2:59.5 and 2:52.0 in a 22.5 ft ceiling site. The 3:10 was an aggressive ceiling hit and great recovery and climb back. The 2:59 barely skimmed the girders and was basically a perfect flight. the 2:52 was 2-3 ft below the girders. The next closest flight (4th place) was 2:30 with another dozen teams flying 2:00 - 2:25 and another dozen flying 1:30 - 2:00. There were 45 HS teams at Michigan States in total.

Our best times in practice this year were as follows (all four teams I coached could do these times repeatedly; all times are "no touch"):

13 ft climb height: 2:20 (yes, we had to compete in an Invitational Tournament with at 13 ft ceiling!)
18 ft climb height: 3:00 to 3:05
21 ft climb height: 3:10 to 3:12
25-26 ft climb height: 3:20 - 3:24

Best flights were always on the 3rd through 5th use of a motor during practice. Even a "warmed up" motor could not quite get to these times in competition. For example, all three teams could fly 3:10 - 3:12 at 21 ft, but at Michigan States we were shooting for 3:00-3:05. The 2nd place team was pretty much right on with a 2:59.5. The 1st place team flew well but was also lucky. They launched with a bit too much torque and hit the ceiling pretty hard in about 40 seconds; then dropped and climbed back to just under the girders. Our normal climb rate was about one minute to 21 ft.

Our typical rubber motor was 11.875" of .0581 g/in with two black rubber o-rings (1.493 grams total). And our typical winding for a good flight to about 25 ft. with this motor was (3rd use of a motor and beyond) was: max turns: 1,500; max torque 1.4 to 1.5 inch ounces; 165 backoff turns; launch torque 0.4 in oz; turns remaining 170 and propeller revolutions per second = 5.75 (some higher altitude flights averaged 4.75 RPS). We got our best results with October 2020 Tan Super Sport (tried some 2015 and 2021; saving the June 2016 in case we ever get to Nationals).

Our trim and configuration was: CG .875" behind rear wing post; 2.8 degrees of decalage; 19.5" tail moment arm (wing high point to stab high point); 3/16" left wing washin; 3/16" tailboom offset; 2 degrees of stab tilt; 1/8" rudder offset; Ikara flaring prop with blade area rear of spar cut off and remaining blade sanded for better flaring and static pitch set to 36 degrees at 3" radius; 2 degrees of thrust line offset.

We tried many propeller pitches and a number of different propellers with many densities of rubber (and a couple vintages) and a number of CG locations and corresponding decalage angles. We found that a more rearward CG flew too efficiently and too fast and let the propeller "spin out". Also the more rearward CG resulted in poor recovery from ceiling hits (6-8 ft drop sometimes). The three of the four schools I coached had varsity and JV teams, so a total of 14 students and 14 airplanes. In total this collaborative group flew over 1,000 test flights this year.

My teams swept the medals at every Invitational they entered except U of M (unfortunate 13 ft ceiling with giant chandeliers and pretty strong drift, etc.) and finished 1st through 7th at Regionals. They flew best times at higher climb of 3:15 after about one month of practices and continued to improve to 3:22-3:24 at 25-26 ft by the end of the year. Particularly proud of them getting 1st through 4th at the Boyceville invitational with 84 teams from 17 states in attendance (40 or 45 flew Wright Stuff and our teams beat some very strong National level competitors). Also, the overall winner of the Boyceville Invitational was a JV team from one of my schools (a couple of very precocious freshman).

Here's a video of a 3:20 at 25 ft climb height. The team banter is pretty funny during the flight and the camera person didn't notice that the airplane was not staying in the frame; oops). Sorry the camera is so far from the airplane.

https://youtu.be/2qkHxQ3_XMM

Brian T.

[newflight]

Brian;

Thank you for posting such useful information. It will surely help teams. It would also be more fun if your teams could be at Nationals

Thanks
Yuming

[bjt4888]

Yuming,

Thanks. Yes, Nationals would be great. I encourage my flying event teams and their teammates to strive for excellence in all events. One team I coach is moving up each year at Michigan States. They made top 10 this year in overall score. Still lots of work to do to get to 1st or 2nd overall.

Brian T

[coachchuckaahs]

At the AMA Nationals in Eagar Arizona, 98' ceiling, Monet Ramacciotti of the Albuquerque Area Home Schoolers put up a great 4:44 flight in the last round! All of the Wright Stuff flyers worked 3 days to perfect their flights, and the times improved throughout the week. Monet made a last minute incidence adjustment (went to 0 on the wing, and all decalage added as negative incidence in the tail) and gained almost a minute on her last flight.

The biggest struggle at Eager was getting the 8-gram planes to the ceiling. Those that did were rewarded with great times. It too patience and thinner rubber to get the best times, and much trimming of the planes to get to the ceiling. Rubber motor loops around 37-39cm were used instead of low-ceiling 32-33cm loops. Flaring props were a detriment. Launch torques were as high as 1.0 oz-in!

Great job to all who participated

Coach Chuck