New F1D Rules
by Don Slusarczyk [email protected]
Effective January 1, 2015, F1D rules will change. The rules change was voted on earlier this year and the result is that the minimum weight for F1D is going up from 1.2 grams to 1.4 grams, and the maximum allowable motor weight will be reduced from 600 mg to 400 mg. This rules change will invalidate all current AMA Indoor records for F1D. The slate will be clean starting January 1, so get those record trials sanctions in!
The long-term effect of this new rules change is unclear. Many were not expecting any F1D rule changes, and the news of the upcoming changes was not publicly known to the Indoor community until shortly before the final vote was taken. Reactions have varied. Some feel participation will increase because of the heavier weight; some feel the rules are too restrictive and will no longer fly the event; and others will fly no matter what the rules are.
A few things are clear with these new rules. The 1.4-gram weight means airframes can be made much stiffer than before. Using carbon will no longer be limited to only propeller outlines and VP hubs. Carbon can be applied to other parts of the airframe such as motor sticks, wing tips, or spars. Next year will prove to be interesting regarding F1D's new technological developments.
The reduced rubber will drop flight times and put a premium on having good rubber. With only 400 mg of rubber, using only the best will maximize flight times. Those with stashes of premium rubber will definitely have an advantage.
A recent topic of discussion has been the expected amount of flight time reduction. The initial approximation is roughly 67% of the previous flight times, because only two-thirds of the current amount of rubber can be used. Several contests this year have been held following both versions of the rules and there is some comparison data.
At the recent Indoor FF Nats in Moscow, Idaho, the winning 1.2-gram F1D two-flight total was 69:32. The winning 1.4-gram two-flight total was 50:10, which works out to 72% of the old time. Brett Sanborn flew under the new rules during the July 4 weekend at Lakehurst, Illinois, and had a 30:07. His record at the same site is 42:03, which is 72% of the previous performance.
After his Lakehurst flying session, Brett made this interesting comment regarding the new 400 mg motors. He stated, "I broke a lot of motors yesterday. It was hard to get the thinner motors up to high enough torque to do any time. That was probably the biggest challenge. So I don't believe the people who say we'll use less rubber because we will be breaking more motors to get a flight off."
Last-Chance F1D Records
Following the rules change announcement, many current F1D fliers have been taking every opportunity to set AMA records with their existing models before the new procedures go into effect.
At the Kent State Indoor contest in April, John Kagan and Brett Sanborn were having an epic F1D battle over the Category II F1D record. As nighttime approached on the last day of the contest, after most of the fliers had gone home, Brett put up an F1D flight that set the Category II record. After processing his model, Brett had packed it away and put his model and support gear into his car. John had also been flying his F1D and his flight was only a few seconds away from Brett's newly set record.
With the flying site rented until 10 p.m. and perfect flying conditions inside, John put up another record attempt. As the seconds ticked by, a now pacing Brett Sanborn went back out to his car and took out his models and support gear and was back in the game. With the entire site essentially to themselves, John and Brett flew until there was no more time left before the building lights would go out. In the end, Brett's earlier record fell and John ended up with a 32:44 for the new Category II F1D record. Hopefully next year's Kent contest will be equally exciting!
AMA Indoor Rules Cycle
The initial vote on the AMA Indoor rules has concluded. All but two of the initial proposals passed. The final ballots were sent out at the end of August and the results will be published September 30 on the AMA website.
Of the proposals that passed the initial vote, the two main proposals to watch for final passage will concern allowing plastic covering on A-6 models and adding 35 cm (F1R) as a new AMA record-setting event.
Mike Kirda's Propeller Blocks
At a recent contest in West Baden, Indiana, I test-flew some new F1L models that I had built. I was unhappy with the propellers because they seemed to require a lot of power and I could not climb much beyond 50 feet.
Mike Kirda was also at West Baden and he brought some propeller blocks that he had cut using a band saw and a special fixture he created. I had been using a propeller block for my F1L that was made years ago, so I bought a 26-inch and a 28-inch pitch block. I put my F1L propellers on the 26-inch block and found that my propellers had much higher pitch.
After I returned home, I compared the new 26-inch block to my old one. The F1L propeller fit my old block, but did not fit the new one. I wanted to find a better way to measure the pitch of these new propeller blocks.
I bought a digital pitch gauge used for RC helicopters on eBay for approximately $15. It gives angle readings to 0.1°. Using this device, I determined that my old 26-inch block had roughly a 33-inch pitch, which explained why my F1L propellers were not working well.
Mike's block had a helical 26-inch pitch at all stations that I measured with the digital pitch gauge. He sells his propeller blocks on his website listed in Sources. They come in balsa or poplar and he will even cut custom-pitch distribution blocks as well.
Until next time, keep the weights down and the times up!
Sources
- National Free Flight Society (NFFS) — www.freeflight.org
- Propblocks.com — [email protected] — www.propblocks.com
Transcribed from original scans by AI. Minor OCR errors may remain.
