Indoor News and Views

Hangar doors on SE side of the building

The hangar doors face to the south east. Around half the doors are single layer safety glass from approximately 5’ to 35’, with the rest being 15’-35’. In the morning, there is a significant amount of solar gain through these windows, heating the floor and any tables set in front of the glass. As might be expected, the heat produces a convection current going up right next to the glass. We observed the effects mostly within 1’ of the glass, although it may spread as wide as 3’ near the ceiling. This was most pronounced on the right side where the glass is larger. It tends to push models off the glass and away.

After the time spent sealing the drafts and holes, the air is remarkably free of turbulence. Close to the hangar doors, there is some due to the convection current.

There is drift. We noticed that right at the ceiling, it goes one way, but 3-5’ below the ceiling, it goes in the opposite direction. In my many F1D flights, I used my pole more for retrieval due to hang-ups than for steering. In nearly every flight steering was not necessary. Balloons may be useful, however I suspect poles are more practical here.

http://www.allfishingbuy.com/Fishing-Pole/Pole-A1-JDS-130-15013.htm

This is the pole I have. I remove the two smallest rods for steering here.

Higher windows facing NW

View along the windows from lift

Midday, sunlight isn’t as much of a factor.

Later in the afternoon, sunlight starts to come in from the north-western windows. In the corner (right side in the photo) Leo commented that the air seems to be more buoyant. As the windows are much smaller, no convection current was noted.

Elevation is 735’ above sea level. Red dot indicates approximate location where temperature readings were taken.

The ceiling height is 44’ 4”. There is a gap between the ceiling and the red beams, seems to be about six inches. Below that is the sprinkler pipe, hanging down a bit more. The sprinkler pipe is where more hangups occur. Additionally, there are lights that hang down.

Safe no touch flights are 40′. The sprinkler pipe is about two feet above this.

I took the above pictures at the ceiling after sealing the last large hole. Above the insulation panels, the temperatures were significantly higher than below.

What is interesting though is how much the insulation moderates the temperatures inside.

Saturday was windy outside, gusting to over 20MPH. Inside was very steady, with some drift but no turbulence. Interestingly the temperatures were very even all day long, with very little difference between floor and ceiling.

I left the temperature logger plugged in overnight. As you can see, the insulation really moderates the temperatures inside the hangar. The concrete acts as a heat buffer I suspect, so the floor temp is more stable than the ceiling. After the sun goes down, the ceiling temps drop below the floor temp, and the 20′ to ceiling height becomes amazingly homogenous. In the morning on Sunday, I put up several F1D flights while the ceiling temps were below that of the floor. The inside air was still, with no hint of turbulence. Outside the wind was about 10MPH in the afternoon.

As the temperature rises more than Saturday, the air temps slowly stratify a bit, with the ceiling a bit warmer than below, however the difference is still fairly minor. There is a bit more of a spread on Sunday than Saturday, which is likely explained by the higher outdoor temperatures and relatively light winds.

There are plenty more dates to fly this summer:

October 1st/2nd – Contest

See the Bong Eagles Rantoul page for details.

Rantoul

Leo Pilachowski sent me the following e-mail and has given permission for posting it here.

I have a few comments on the convection cells and the air at Rantoul.

The fast ceiling drift and the slower opposite direction drift a bit below the ceiling are common results of the a flat ceiling building’s convection currents.  The air rises over the hot spot, in this case the concrete the sunlight falls upon.  Upon reaching the ceiling, this air needs to go somewhere so there is the drift away from the sunlit spot.  Since these spots are near the walls at Rantoul, the air closes off in the direction away from the wall.  The rising air needs to be replaced by other air so there is a lower height drift toward the sunlit spot.  The difference in speeds is caused by the hot air having a smaller cross section right up at the ceiling resulting in a faster speed to move the same volume of air as is sucked in below.  Obviously, there is a fast rising thermal at the sunlit spot.  The accompanying downdraft, however, is pretty much over the whole rest of the building, lessening a bit toward the far walls.  This is because the air along the ceiling continuously cools and then falls, completing the convection cell.  I noticed this most of the time during the event weekend.

What is neat about the Rantoul hanger is the thick concrete floor.  The sunlit spots get a warmer surface and heat the air.  However, when the sun stops shining upon the spot, say when a cloud blocks the sun or the sun is high in the sky around noon, the concrete surface cools back down to the internal temperature.  Then, the convection cell gets weaker and even stops.  This, I think, along with the evening after dusk, is the best time for flying at Rantoul.  The air is essentially driftless and there is no large area downdraft.  Even a minor downdraft can affect times and a plane does not stay over the hot spot long before drifting out.  Note that one inch per second downdraft is five feet per minute.  I found that my F1L descent rate last Saturday evening at Rantoul was fantastic and nearly as good just after lunch on Sunday.  I would rather have driftless air with no up and down drafts than convection cells as, unless one continually steers into the up draft, much more time is spent in the downdraft.  I think that the evening flying at the Rantoul Nats will be great.

Kibbie has a similar convection cell setup.  The fast ceiling drift is called the “jet stream” and will take a plane 300’ in a matter of minutes.  F1D’s near the Kibbie ceiling need to be steered (with hardly any room for a balloon under the ceiling tile clouds) many times during the high portion of the flight.

Leo

Tim Stone offers the following: The walls there are deadly. Slide down and you are almost guaranteed to get stuck. (Good advice – Steer before you get into trouble. Hangups can easily occur on the hangar door or below the windows. The area by the dock doors can be especially hard to steer out of.)

Bill Gowen offered the following observation: (Am paraphrasing)

On smaller models with droop booms, the sprinkler pipes are sure to be a problem.

Kibbie Dome Raffle

In light of the challenges to fund the Kibbie event during an off year (not hosting USIC/Nats or F1D team trials), I’m putting together a raffle with some great prizes.  This raffle will be run similar to the one Kang put together in 2012.

John Kagan’s F1D

Click here to download a PDF of the plan.

Comments from John:

#7 (aka Sleven, when it is doing well)

Sleven was built in 2003.  It held the high time at the 2004 WC; finished 2^nd once, and 3^rd three times at the WCs; and has won several team selection contests.  Other models in the box want to be like it, but they don’t know how.  Interestingly, #7 has had three motorsticks and many props, all with equal success.

2016 U.S. Team Manager’s Report

2016 U.S. F1D Team Manager’s Report

The 2016 cycle saw the largest American presence at a World Championship in more than a decade. The United States fielded a full Junior Team for the first time since 2006 as well as both the junior and the senior returning World Champions. The team, coupled with our supporters, and our Canadian friend Dmytro Silin numbered 14 people. The group arrived in Slanic prior to the start of the Otto Hints Memorial (with the exception of Wyatt Wear and Joseph Szczur, who arrived on the 9^th to minimize their time away from school). Almost everyone’s trip over went smoothly, but Yuan Kang Lee and Jake Palmer missed their connecting flight out of Istanbul, and did not arrive in Slanic until 4am on the first day of the Otto Hints.

Aurel Popa graciously helped arrange the Otto Hints and our accommodations during the pre-contest. Having the time to acclimate and practice before the World Championships goes a long way to level the playing field for the countries that do not get to regularly fly in the mine. The majority of the U.S. fliers used the Otto Hints to practice and experiment with new models, but John Kagan managed to fly every round of the Otto Hints and posted a high time of 24:32. His approach left him well prepared for the start of the World Championships.

The team had a day off between the Otto Hints and the start of the World Championships. However, in case anyone had any doubts about using the time to tie motors, and make repairs, a constant light rain kept the team from venturing too far from the Hotel Roberto.

The official practice day was scheduled to be short, from 7:30am to 2pm, and everyone I talked with had a plan in place to maximize what little flying time they had. Unfortunately, the air was much more turbulent than it had been during the Otto Hints. We noticed that organizers had allowed minibuses to drive across the mine to the flying area, and to do so, had opened a series of double doors. It was thought that this is what had disturbed the air. The officials agreed to delay the opening ceremonies in favor of more flying time.

After a short opening ceremony, the teams were instructed to move their tables out of the flying area and into a small preparation area. The official diagram indicating which countries were supposed to go where was contradicted by verbal instructions from the organizers. Thus, some two hours later, the tables were outside of the flying area, but neither the competitors nor the organizers were quite satisfied with where all the tables had ended up.

At the technical meeting later that night, it was agreed that doors to the mine would be shut, except for when vehicles needed to enter or exit the mine to transport disabled persons. Controlling the doors helped to keep the air flyable. Nevertheless, the turbulence definitely influenced the results of the contest.

In order to help the rounds run as smoothly as possible, Jake Palmer served as Kang’s assistant and the seniors gave up their practice time to caddy for one another, while I managed the junior flights. All involved felt that this was the least disruptive option. We needed to make 8 official flights in a three-hour window and only the returning world champions could fly at the same time as the other team members.

Joshua Finn started off round one with a 20:48 for the seniors. John Kagan followed up with a round one high time of 25:43, while Brett Sanborn posted a 24:02. Kang’s first round flight proved that out climbing the site would still be an issue with the new rules. He hung on the catwalks at 7:05. Wyatt started off for the juniors, and even though he was still working on trimming his model, he was able to put up a 10:33. David Yang landed a solid 20:20 and Joseph did a 12:23 to finish out the round for the team. Evan Guyett’s flight struggled to get the altitude it needed and landed at 15:07.

Round two was largely about getting a good backup time on the board before attempting more aggressive flying. To that end, John up a 24:52, and Brett posted a 22:51. Joshua landed a 20:14, which put the team in first place after day one. Kang suffered a damaged boom and struggled to get the model retrimmed in time for the end of round two. Evan and David improved their first round times with an 18:18 and a 20:58 respectively. Wyatt posted an 8:08 and Joseph closed out the round with an 11:29. The U.S. juniors needed to improve by 16 minutes in order to catch up to the French in 3^rd place.

After a strong start the previous day, the third round saw many in the American contingent struggle to better their previous times. The air was still quite turbulent, perhaps even more turbulent than the previous day. John and Brett posted a 23:07 and 21:06 respectively. Joshua flew a 20:20 that bettered his backup time by 6 seconds. Kang finally managed to break 20 minutes with a 22:33, but the time was still too low to move him into the top ten.

The juniors also had mixed results in round three. David improved his best time by 2 seconds with a 21:00. Wyatt made a 4 minute and fifteen second leap over his round one flight, while Evan and Joseph were unable to surpass their times from the previous day.

After a quick lunch, round four began. John flew first for the seniors and landed a 23:32. Brett followed up with a 24:36 that was good enough to move him into second place momentarily. Joshua landed a 21:43, which helped to raise the team score to 141:44. Kang finally cracked the top ten with a 23:20. The juniors improved significantly as well. Evan posted a 20:28, which was a 2 minute and ten second improvement over his previous high time. Wyatt landed a 16:30 and improved the junior team score by 5 minutes and 47 seconds. Joseph and David both posted round four flights that were slightly under their back-up times.

At the end of the day, 2 the U.S. seniors were sitting on top, but everyone was aware of how quickly that could change. Calin Bulai rose to the top of the juniors with an incredible 25:45, and surpassed John’s 25:43 for the high time of the contest. If Zoltan Sukosd was able to land the big times he previously had shown he was capable of, the U.S. was going to need to improve to keep up.

The final day of the World Championships feature special kind of anything can happen tension and optimism. It was Brett’s turn to fly first for the seniors. Despite having slid down the wall onto the invisible ledge during Otto Hints when he had climbed above the catwalks, Brett decided to use the full height of the mine once again. After flying between the catwalks he landed at 24:11. While the risk had not been rewarded, he did get the model back in one piece. Joshua’s flight did not climb as expected and only got about three fourths of the way up. John’s round five flight hit the wall, but he was able to get the model off with a balloon before it stuck. Evan after losing significant altitude, the model landed at 25:18, which increased his backup time by 26 seconds. In case we had any doubts that the air might have improved, as John was landing, we heard clapping from across the mine. Zoltan had just landed a massive 26:37, thus establishing a new high time for the contest.

Kang launched at the end of the round and his model climbed quickly to the roof. He spent a few minutes flying between the catwalks and bumping the ceiling. It felt like the entire mine was watching his flight. Miraculously, the model descended below the catwalks. It was clear that it was going to be a big flight, but we had to wait for the model to land to see just how big. The model touched down to applause at 27:59.

The juniors all improved in the fifth round. David lost the model he had been flying during the morning practice session to the invisible ledge. He was able to get the majority of the model back, but the wing was beyond repair. He switched to his backup model, and did a 23:04. Evan flew a 21:12 that bettered his previous high time by 44 seconds. Joseph increased his previous high time by a minute and 33 seconds with a 14:06. Wyatt increased his backup time by 30 seconds with a 15.18.

The Hungarians moved into the top team spot after round five, and the field of contenders for the individual world championship title appeared wider than it had since the start of the contest.

The contest came down to the final round, with mere seconds separating first and second place. Brett flew first for the U.S. seniors. He tried a different model, but it did not fly as long as the one he had been using. John changed to a slightly longer loop and put up a 26:56. Joshua also switched models and the new model dove into the ground shortly after launch. Even after a relaunch, the model continued to dive. David and Evan both strove to pack in more turns and torque for their final flights, but their models stalled badly on launch. They were not able to recover their models in time to relaunch. Joseph increased his by 59 seconds with a 15:05. Wyatt’s last flight did not climb as high as the previous flight, and landed at 12:37. Kang decided to take a more conservative approach and flew below the catwalks. He still posted an impressive time of 26:55, which was enough to secure him the World Championship Title. Zoltan flew valiantly, and his final flight was 27:57. Only 30 seconds separated Kang from Zoltan. John finished out in third.

Tony Hebb put up an impressive 26:42 in the last round and moved the British into 3^rd behind the U.S. The Hungarians came out on top. Interestingly, the last time the U.S. won the individual title, but not the team title, the Hungarians were in first.

It was a privilege to return the mine, especially in the company of the U.S. team. I enjoyed to getting to see old friends and make some new ones. It was also great to see how Slanic, and the mine have changed in the ten years I have been away. I want to thank our supporters who weathered the week underground with us, and Bud Layne of Spantech for his generous support of the team. I am looking forward to seeing everyone in two years at West Baden

Nick Ray – U.S. Team Manager