Author: B. Tenny
Edition: Model Aviation - 1995/03
Page Numbers: 122, 123, 124
,
,

FREE FLIGHT INDOOR

Bud Tenny, P.O. Box 830545, Richardson, TX 75083

A Letter to the East Coast Indoor Modelers

I regret to begin this letter with sad news. Long-time ECIM member Manny Radoff left us Wednesday, October 5. Manny's dedication to indoor modeling and Lakehurst spanned many decades.

His ability to be a keen competitor and light builder won him top honors of a national record and team-member status at the World Championships. He was a pioneer in the evolution of indoor model design. Not being satisfied with the multi-rib wings that were the standard, Manny was the first to utilize the five-rib wing planform that we all use in our models today.

Locally, Manny was a good friend. You could always count on seeing him at our flying sessions and at every one of our social gatherings.

Participation in flying events was only one side of Manny's greatness. He was part of the original inception group and president of our East Coast Indoor Modelers organization. In addition, he served as our regional representative for the FAI competition committee.

I personally will miss his help, encouragement, and mostly his sincere friendship.

Gary Underwood

USIC!

The 1995 US Indoor Championships is go again — a five-day meet with test flying the first day. The dates are May 31–June 4, 1995. As of this writing (11/6/94) final details are being decided and entry blanks prepared. Send a SASE to Howard Henderson, 444 Bryan Ave., Kirkwood MO 63122 to get an entry blank.

International Easy B Contest!

Provided enough interest is shown, there will be an international Easy B contest as part of the Kibbie Dome meet (early July). The contest entry fee will be high ($35) with very special prizes. Since proxy entry will be allowed, proxy fliers will be needed. Contact Larry Coslick, 4202 Valleycrest Hills, St. Louis MO 63128 if you are interested in entry or proxy flying.

Treatise on Jug Props

A previous column noted that Phil Alvirez developed and published a geometric design method for jug props. Phil's method uses almost no mathematics for design and analysis. The book is well written and shows how to develop props on cylindrical forms. He has released an added page that extends the method to full-helical-pitch design and is updating all who previously bought the book. Phil asks $10 postage paid for this 24-page manual. His address is 1350 Arncliffe Pl., Windsor, Ontario, Canada N8S 4K3.

Best of The Hangar Pilot

By the time you read this, Dave Linstrum will have completed the last two volumes of this compilation of plans and articles from John Martin's long-lived newsletter. Vol. 4 + Vol. 5 is $14. Vols. 1–5 is $34. These prices are postage-paid delivery. Dave Linstrum, 3927 Maravic Pl., Sarasota FL 34231.

Flying Opportunities

The sessions listed below are the latest information available. Contact persons for other areas are included. Clubs with events beginning in April 1995 send schedules ASAP! Always verify a contest date by phone before leaving home!

  • California — Burbank. The Blacksheep Exhibition Squadron (VMF-214) has monthly sessions on second Fridays; flying in Cat. I site at Luther Burbank Middle School; 7–10 p.m. Tony Naccarato, 2121 N. Hollywood Way, Burbank CA 91507. Tel.: (818) 842-5062.
  • California — Garden Grove. We currently have access to the gymnasium located at the Crystal Cathedral in Garden Grove, California. We have use of the gym every Tuesday evening from 7 to 10 p.m. We welcome all types of indoor models as well as modelers of any experience level. The gym is approximately 25 feet to the lowest ceiling girder with another 10 feet of airspace above. John Wenk, 4621 Silverleaf Ave., Orange CA 92669; Tel.: (714) 633-8546.
  • California — Los Angeles area. Monthly sessions at the Naval & Marine Corps Armory, next to Dodger Stadium. Paul Avery, 6360 Germania Ct., Agoura Hills CA 91301; Tel.: (818) 707-0282.
  • California — Marin County (20 miles north of San Francisco). Year-round mini-contests, 8 a.m.–2 p.m., fourth Sunday each month; site is a standard basketball court with 28 feet clear. Contact George Benson, 204 Benson Circle, Mill Valley CA 94941; Tel.: (415) 388-1809.
  • California — San Diego. Fun Fly and Scale sessions 2nd Friday each month; monthly sessions on 4th Friday, all in Colina Del Sol Community Center (Cat. I); 5316 Orange Ave., San Diego. Howard Haupt, 3860 Ecochee Ave., San Diego CA 92117; Tel.: (619) 272-5656.
  • Canada — Ontario area. Dan O'Grady, 50 Largo Crescent, Nepean, Ontario, Canada K2G 3C7.
  • Canada — Winnipeg, Manitoba. Flying sessions twice a month in a 23-foot gym on Sundays and one session each month in an 80-foot hangar. The hangar is a commercial airline maintenance hangar subject to work schedules; no sessions have been cancelled yet. The hangar is very tight, with minimal drift, and is the locale for several Canadian Cat. III records. Contact Barrie Taylor, 2 Thackery, Winnipeg, Manitoba, Canada R3K 0H1; Tel.: (204) 889-4737.
  • Connecticut — Glastonbury. George Armstead, 89 Harvest Lane, Glastonbury CT 06037; Tel.: (203) 633-7836.
  • Connecticut — Norwich. Flying sessions are held throughout the fall and winter at Teacher's Memorial Junior High School in Norwich, Connecticut. Beginners are welcome with assistance provided by veteran aeromodelers. Sessions for 1994–95 are scheduled for Saturdays from 9 a.m. to 1 p.m.: February 18, March 18, and April 15, 1995. Contact John Koptonak, 3 Wiemes Ct., Waterford CT 06385; Tel.: (203) 442-9003.
  • Connecticut — Wilton. Roger Kleinert, 17 Gardiner St., Darien CT 06820; Tel.: (203) 655-1585.
  • Florida. Contact Dr. John Martin, 2180 Tigertail Ave., Miami FL 33133; Tel.: (305) 358-6363.
  • Georgia — Atlanta area. Contact John Barker; Tel.: (404) 436-9911.
  • Idaho — Kibbie Dome. Andy Tagliatico, 650-B Taybin Road NW, Salem OR 97304; Tel.: (503) 371-0492.
  • Illinois — Chicago area. Year-round weekly sessions in a 25-foot gym at College of DuPage in Glen Ellyn, Illinois. Currently held 6–11 p.m. on Monday evenings. Bob Warmann, 245 N. Oaklawn, Elmhurst IL 60126; Tel.: (708) 834-9075.
  • Iowa — Cedar Rapids. Non-sanctioned indoor flying, Nov. 1994 through Feb. 1995. Paul McIlrath, 1524 48th St. NE, Cedar Rapids IA 52402; Tel.: (319) 393-4677.
  • Kansas — Topeka. Jack Koehler, 3425 SW Arrowhead Rd., Topeka KS 66614-3485; Tel.: (913) 272-8439.
  • Kansas — Wichita. Contact Stan Chilton, 725 E. Lincoln, Wichita KS 67211-3302; Tel.: (316) 686-9634.
  • Kentucky — Louisville. Flying sessions every Tuesday at the Sawyer Park site, 11 a.m.–1 p.m. Also, one Saturday each month (subject to military schedules) at the Kentucky Air National Guard suite 10 a.m.–2 p.m. Contact Mason Plank, 3207 Oriole Dr., Louisville KY 40213; Tel.: (502) 634-8191.
  • Maryland — Goddard NAS. Contact Tom Valle, 4444 Henryton St., Laurel MD 20707; Tel.: (301) 498-0790.
  • Massachusetts — Cambridge (MIT). Ray Harlan, 15 Happy Hollow Rd., Wayland MA 01778; Tel.: (617) 358-4013.
  • Minnesota — Burnsville. John O'Leary, 11425 Kell Circle, Bloomington MN 55437; Tel.: (612) 888-0638 or Dell Marchant, 1170 24th Ave. N., Plymouth MN 55447; Tel.: (612) 473-5971.
  • Nebraska — Beatrice. John Pakle, 4523 Poppleton Ave., Omaha NE 68106; Tel.: (402) 551-2964.
  • New Jersey — Lakehurst. 1994 flying sessions/contests/record trials at Hangar #1 were scheduled almost every weekend between July and the end of October. For information on the 1995 season, send Gary Underwood a SASE at 24 Kennebec Ct., Bordentown NJ 08505 or call (609) 324-9004.
  • New Jersey — Northern area. Don Ross, 38 Churchill Rd., Cresskill NJ 07626; Tel.: (201) 568-5272.
  • New Jersey — Union area. Fergus Collins, 48 East Hazlewood Ave., Rahway NJ 07067.
  • New York — Brooklyn. Contact Don Ross, 38 Churchill Rd., Cresskill NJ 07626; Tel.: (201) 568-5272.
  • New York — Levittown (Cantiague). Richard Fiore, 531 Secatogue Ave., Farmingdale LI, NY 11735; Tel.: (516) 249-4358.
  • New York — Locust Valley. Fred Dippel, 2 David Court, Glen Cove, LI, NY 11542; Tel.: (516) 671-2858.
  • New York — NYC. Dan Marek, 210 West 101st St., #10F, NYC 10025; Tel.: (212) 222-1546.
  • New York — Queens. Bob Bender, 159 Raff Ave., Mineola NY 11501; Tel.: (516) 248-5118.
  • North Carolina — Charlotte. Flying sessions at a 25-foot gym every Friday night, year-round. Contact Cliff Culpepper, 1401 Ferncliffe Rd., Charlotte NC 28211; Tel.: (704) 366-7350.
  • Ohio — Cleveland area. Weekly sessions year-round in Cat. I sites. One site in Willoughby is at the Andrews School and has a 20-foot flat ceiling with 60 x 80-foot floor area. The other site is at Meridian Euclid Hospital in Euclid and has a 19.5-foot ceiling and 45 x 70-foot floor area. Contact Vern Harker, 25599 Breckenridge Dr., Euclid OH 44117-1807; Tel.: (216) 486-4990.
  • Oklahoma — Oklahoma City. 1995 flying sessions/contests at the Armory: Feb. 19, Mar. 19, 1995. Contact Edsel Ford, 10813 W Country Drive, Oklahoma City OK 73170; Tel.: (405) 691-5411.
  • Oklahoma — Tulsa. Roy O'Mara, 9120 E. 7th St., Tulsa OK 74112; Tel.: (918) 835-6880.
  • Oregon — Albany. Sundays, Jan. 29 and Feb. 26, 1995, 9 a.m. to 3 p.m. The gym will open at 8:45 a.m. Schedule for both meets: 9 a.m. to 11:45 a.m. HL/CL — 11 a.m. Twin Pusher — 11:30 a.m. Noon to 3 p.m. Duration events. Events: EZB, Pennyplane, Limited Pennyplane, Intermediate Stick, Omni-topper, MiniStick, Scale, P-24, Bostonian, Indoor HL Glider, Catapult Glider, Helicopter, Old Timer Challenge, Moorhead Event, and Twin Pusher. Mass launch. Site: South Albany High School Gymnasium, 375 S. Columbus St., Albany OR. Ceiling 42 feet. All entrants must wear gym shoes. Contact Bob Staicik, 5066 NW Picadilly Cir., Albany OR 97321 or John Lenderman, 17086 Hall Road, Clatskanie OR 97016; Tel.: (503) 728-3884.
  • Pennsylvania — Eastern. Walt Eggert, Jr., 26 Moreland Rd., Huntington Valley PA 19006; Tel.: (215) 947-4387.
  • Pennsylvania — Philadelphia. Joe Krush, 403 Wagner Rd., Wayne PA 19087; Tel.: (215) 688-3927.
  • Virginia — Hampton area. The Langley Brainbusters' winter indoor contest schedule includes these dates: Jan. 29, Feb. 26, Mar. 19, and Apr. 23, 1994, 1 p.m. to 6 p.m. All contests will be held at the SBH Gym and will feature the following events: EZ-13, Limited Pennyplane, Bostonian, No Cal, A-6, bench hand-launch glider, and MiniStick. All events count for scoring. Contact Abram Van Dover, 112 Tillerson Dr., Newport News VA 23602; Tel.: (804) 877-2830.
  • Washington state — Seattle area. The Boeing Hawks have scheduled three contests for 1995, all at the Naval Reserve Center in Lake Union, from 9 a.m. to 4 p.m.: January 14, February 18, and March 18, 1995. Contact Gene Stubbs, NWS 67-ML 237, c/o 19, 5505 Ann Arbor NE, Seattle WA 98105; Tel.: (206) 523-6148.
  • Wisconsin — Racine. Tony Italiano, 1655 Revere Dr., Brookfield WI 53005; Tel.: (414) 782-6256.

Partial Motors

This topic has come up before in this column, referring to quarter- or half-motor testing to refine model trim or to actually predict time and maximum altitude to be expected from full motors. (For those who may not have seen earlier discussions, partial motor trimming uses a weighted spacer to replace part of the motor on an indoor model.)

For a half-motor test, the length of the spacer is exactly half the distance between the front and rear hooks on the motor. The front hook must have an extra loop of the rubber very near the body of the motor; the rear hook must be used with a loop of the rubber you intend to use that is of identical weight.

Quarter-motor testing is more common, with the spacer three-quarters or less in size than the hook measurement and weighing three times as much as the short loop. Finally, the ratio of full-motor length to the partial-motor length must be exactly the same as the ratio of weight. Stan Chilton strips short strips, and is careful to make the motor from shorter sections immediately adjacent to the full motor.

How good is the prediction? Stan Chilton claims almost exact correlation between quarter-motor times and full-motor times. He estimates test altitude, so he can't be sure about altitude. If his test altitude estimates are correct, the altitude correlation is good also.

For his quarter-motor tests, Bob Randolph claims that the model goes at least as high as predicted and achieves at least four times the quarter-motor time.

How exact is your hang? Basically, be as exact as you can manage. Stan Chilton uses an electronic balance with 0.1 g sensitivity, and Jim Clem uses a precisely constructed ratio beam balance. Precise is good—but you must have an equally good altitude measurement to predict peak altitude.

Environmental concerns: As with any rubber-powered event, ambient temperature is a major variable. Rubber has a positive temperature coefficient, so it gains energy as the temperature rises. The approximate theoretical gain is 0.4% per degree centigrade — about 4% power gain for each 10° of temperature increase. So where you suspect a large temperature differential, follow a large-motor test with a half-motor test. An alternate choice is to somehow measure the temperature at altitude and compute a correction to turns/launch torque figures. I can figure how to profile the temperature of a site, but the correction calculations require data I don't have now.

Suppose you only want to solve torque/burst rpm problems? Here, your ratio of rubber weight to spacer weight need not be highly accurate, but you need to be very accurate on the total weight of rubber and spacer. Also, you absolutely must keep the model's center of gravity the same as when you fly it for real. In this case, the short motor gives you good test flights that don't take a long time, and (hopefully) don't get too high.

Other uses for partial motors: By now, the US Indoor Team's resounding success at the 1994 World Championships in the salt mine should be well known. In past years, a major problem has been to make use of the approximately 210-foot ceiling. Low temperatures in the mine reduce motor output energy in ways hard to prepare for.

All three members of the US team practiced at Santa Ana until they had a combination of prop and rubber size such that they could reach the top of the hangar on quarter motors. The expectation was that colder air would reduce the (normally predictable) 600-foot climb to a safe value. Apparently it worked!

West Coast fliers planned a December 4, 1994 F1D regional trials, but had only one-day access to the site. They decided to allow only half-motors so all flights could be made in one day. I can think of no better testimony for partial-motor flying!

Transcribed from original scans by AI. Minor OCR errors may remain.