FREE FLIGHT INDOOR
Bud Tenny, Box 830545, Richardson TX 75083
ABOUT eight months ago chit-chat between Del Ogren and Roger Schroeder developed the concept of an Internet-based postal contest for the A-6 class. The A-6 class was proposed by Clarence Mather, and the San Diego Orbiteers club published the rules and began promoting the event. The first such contest is history, with excellent results, including an imposing international entry. Hats off to Del and Roger!
The data below was taken from the Internet. Complete results are available from http://n-lemma.com/indoor/.
- Andrew Tagliafico — Time: 6:40 — Adj Time (sec): 415 — Ht.: 47
- John Lenderman — Time: 6:36 — Adj Time (sec): 441 — Ht.: 47
- Akihiro Danjo — Time: 6:26 — Adj Time (sec): 400 — Ht.: 48.3
- Mark Allison — Time: 6:23 — Adj Time (sec): 398 — Ht.: 47
- Lew Gitlow — Time: 6:03 — Adj Time (sec): 378 — Ht.: 47
- Emil Schutzel — Time: 5:05 — Adj Time (sec): 334 — Ht.: 26.5
- Bill Shailor — Time: 5:04 — Adj Time (sec): 333 — Ht.: 26.6
These are the six highest adjusted times. Note the time of Andrew Tagliafico at 6:40. The fudge factor is 2/3 second per foot of ceiling height difference from 70 feet.
The following have been abstracted from Roger Schroeder's comments, also posted on the Internet at http://n-lemma.com/indoor/:
It has been my pleasure to be the Contest Director for the first A-6 International E-mail contest. This was made possible by the generosity of Del Ogren, who maintained the web site and regularly posted the new results.
It was an international event with entries from England, Australia, Finland, Argentina, Japan, and the U.S. You are all winners for participating. I believe between eight and ten fliers had never built an indoor model before. A lot had never built an A-6 model.
The participation by beginners was especially good, due mostly to the efforts of Don Park, a teacher at Piper Middle School in Kansas City, Kansas.
I believe that A-6 is now established as a low-cost, low-tech, fun-type competitive indoor event. Where can you find airplanes that cost less than the admission to a show and still fly indoors for times of four to seven minutes?
Del and I hope that some large club will adopt the A-6 event, encourage competition, and maintain a consistent set of rules. Many have kindly offered suggestions about rule changes.
Most were concerned with the tissue-covering rule. Gampi paper is the lightest tissue for an A-6, but it is only available from two sources here in the U.S. and is relatively expensive.
Other comments concerned the 1/32 diameter wire size and Akihiro pointed out that outside the U.S. wood is in metric sizes of 1, 1.5, 2, 3, etc., and that 1/16 square and 1/32 sheet is not available without sanding to size.
To address these concerns, I propose that the following rule changes be made:
- Add a rule that the minimum model weight without rubber be 1.3 grams.
- Allow any covering material — plastic, paper, microfilm, etc.
- Eliminate the wire-size rule.
- For builders where only metric wood sizes are available, 1.5 mm wood may be substituted for 1/16 wood and 1 mm may be substituted for 1/32.
The important rule is the minimum weight. After that, the worry about covering materials, wire sizes, and small variations in wood sizes goes away.
Boeing Model Activity
Thanks to a lot of hard work by several people, Boeing employees at three locations have regular access to indoor sites. Keith Varnau gave this brief report:
After almost six years, BEAMS (Boeing Employees' Aerodynamic Modeling Society) is up and running in three locations: Everett, WA; Seattle, WA; and Wichita, KS. Leadership has changed and their focus remains basically the same, sharing technical skills with adults and youth together.
Indoor E-mail
The Indoor Group has more than 145 members who registered with Bud Tenny at rtenn@nstar.net by sending an e-mail request to that address. They receive late-breaking news as it happens.
All clubs holding indoor events can send announcements of these events to Bud Tenny via e-mail or snail mail (Box 830545, Richardson TX 75083) for prompt posting to members of the Indoor Group and on Del's web page. Come join us!
Indoor Electric
Bob Wilder has made another one-hour-plus flight (1:19:08) in the same Cat. II site where he made the previously reported 63-minute flight. This time there was a sanction in effect and there were eight or ten witnesses. After the flight passed 50 minutes, there was some talk about potty breaks and sending out for food.
The model still had enough energy to climb slowly after the time passed 60 minutes, but the last five minutes were possible only because the site was long enough for prolonged level flight. At very low power levels, the model sinks while turning and drifts slowly higher in straight flight. In a much higher site, the descent could have been longer from a high altitude, but this site is only about 34 feet high.
- Wing: 40-inch span with 250 sq. in. area.
- Weight: 110 grams.
- Battery: 4 × 550 mAh NiMH weighing 48 grams.
- Motor: Wes-Technik DC-5 with a Wes-Technik 8 × 4 carbon-fiber prop.
- Gearbox: homemade with 7.5:1 ratio.
- Control: nonproportional rudder and on-off motor control from a modified Twin Turbo two-channel radio.
- Covering: 1/2-mil Mylar™.
Since the record flight, Bob has redone the model with a different radio and batteries, for a 15 percent reduction in weight.
Bob Clemens staged an indoor contest in the Buffalo Bills fieldhouse at Buffalo, New York. This event may help establish a pattern of access that may help us find indoor sites in other parts of the country. Besides regular indoor events, the meet featured an Indoor Electric FF event. Bob's report of the Electric event:
- Dan Hurd — Thistle — 11:00
- Mark Whalen — Mastodon — 9:06
- Clarence Hurd — Thistle — 5:47
The Thistle is a small all-sheet, pod-and-boom design that uses one of the small Kenway motors in a pusher setup on the pod (construction article about two years ago in Model Aviation). Don Srull brought along a very light indoor RC model, which he flew for one hour and 31 minutes, finally landing out of sheer boredom.
We had 50 contestants, which meant we were able to break even financially on the meet. The Buffalo Bills fieldhouse cost us $1,000 for the day, but it was well worth it. I believe the word-of-mouth we'll get from this contest will ensure an even better turnout in 1999.
Speculation
(From the BEAM newsletter, Gene Stubbs, Editor): The recent return of astronaut Shannon Lucid from the Mir Space Station got me thinking, "What would I do if I were marooned in the space station for six months?" I would do what I always do in similar situations: I would open up my smuggled package of balsa and start building MiniSticks!
How would a typical indoor aircraft fly in weightlessness? Sure, the flight times would be great, but what about stability? With no gravity, there would be no sideslip — the dihedral would be ineffective, and the aircraft would probably just spiral around in a corkscrew pattern.
Rather than striving for the maximum flight time, an indoor contest in orbit might have as the goal to achieve a stable, circular flight path. After some thought, I decided that a regular MiniStick in weightlessness should fly in stable loops.
Let's say you have a MiniStick that weighs 1/2 g and is trimmed to cruise on Earth at an airspeed of 2 meters per second. In weightlessness, it would execute a loop with a 4-meter radius. The centrifugal force would equal the aircraft's 1/2 g weight on Earth, which is equal to its lift. We could add ballast to bring the gross weight (mass) up to, say, 1.2 g, which would make the stable loop radius a more-reasonable 1 meter.
Since the aircraft can't tell the difference between gravity and centrifugal force, an instability mechanism that is active on Earth should still be active in weightlessness. A roll disturbance, for instance, would lead to a sideslip, whereupon the dihedral would kick in to right the aircraft. Any increase in loop radius would be like reducing gravity on Earth; the aircraft would climb back to the stable loop radius at which the lift and centrifugal forces cancel.
Equal Blade Flare?
Jim Clem's continuing experiments on prop efficiency and prop flaring led to the test rig shown in Photos 1 and 2. Most of us use some sort of pitch-measurement rig to ensure our props are what we think — the same assurance is important for the amount of flare. Unequal flare, like unequal pitch distribution between blades, causes prop wobble that diminishes flight time. Jim uses plug-in blades, so it is easy to clamp the blade in place and tie the twist on the hub end of the prop with a weighted beam. Equal twist can then be twiddled into the blades just before assembling the blades to the hub. Photo 1 is before adding weight to the beam, and Photo 2 shows the displacement for an arbitrary twisting moment.
Field Support Equipment
Nick and "Nickel" Leonard, the father-son team now concentrating on F1D models, have constructed some awesome support equipment.
A photo shows their torque stand; one of the best I've seen. It uses their helium bottle as ballast, and disassembles into a small pile of pieces for easy transport. The best thing about this rig is that it puts the torque meter at a convenient height — no bending over while winding!
Transcribed from original scans by AI. Minor OCR errors may remain.
