National Free Flight Society

Clarification on Engines for Vintage FAI Periods 6 and 7

News Release  

The NFFS Vintage FAI Power Committee has voted to make a change in the engine qualifications in the existing list for Vintage Period 6 and 7.

In accordance with the competition rules adopted by the NFFS Board of Directors as stated in the 2022-23 NFFS Rulebook: “All rules presented in this document are official unless noted as provisional. Official rules are subject to the two-year rules cycle described in section 3.2…. “

Additionally, the competition rules require that all rules changes be published on the NFFS website and in the NFFS Digest.

Finally, as the preamble to the Vintage FAI rules in the NFFS Rulebook states, in part:

“The intent of the vintage FAI power event is to build and fly the historic FAI power models as they were originally designed in a competition where the rules have reproduced each time period in such a way as to make one period reasonably competitive with the others….”

The existing rules have defined all of the 7 vintage eras in accordance with historic CIAM (FAI) groupings, making adjustments to design and engine and flight specifications over the years from the early 1950’s until 1979. However, when it came to vintage 6 and 7, engines were lumped together as follows:

“18,2,5 Vintage Period 6 & 7
Rossi, Super Tigre, Cox Conquest, Cossi, A.D.15, K&B 15 Series 72”

What is complicating about the engine grouping is that the model designs for Vintage 6 and 7 are specified, as follows:

18.1.6 Vintage Period 6
Models designed to rules in effect Jan. 1, 1971- Dec. 31, 1975.
As per Vintage Period 5, all rules apply except tuned pipes are banned.

18.1.7 Vintage Period 7
Models designed to rules in effect Jan. 1, 1976 – Dec. 31, 1979.
As per Vintage Period 6, all rules apply except engine run decreased.

Recently, a newly modified release of the Conquest engine became available to the public, and its performance was far above the level of performance of other engines used in Vintage Power.  After reports of this performance were publicized, an inquiry by an interested and active free flightier posed this question: Why is this engine allowed to compete in V-6 when it did not become commercially available until 1976?

At that point, a major review of the literature ensued, and for over a month, various national snd international publications were researched. The results were unequivocal. The Cox Conquest was released to the general public sometime during 1976. The LM Cox Corporation  published a full page ad in the October, 1976 issue of Model Builder announcing the availability of the Conquest.

Inquiries to a number of long time FAI fliers revealed that some individuals were provided prototypes of the engine prior to 1976; however, no nationally published documentation has surfaced that the engine was available to the general public prior to 1976. 

So, in response to the inquiry and to the extensive research done, the Committee was asked to modify the engine listing as follows:

18.2.5 – Vintage Period 6 (new)
Rossi, Super Tigre, AD 15, K&B 15 Series 72 

18.2.6 – Vintage Period 7 (new) 
Cox Conquest and any derivatives including Cossi

Committee members cast their votes, and by a vote of 4 to 1, the change passed. Effective January 1, 2024 these are the new official engine definitions for Vintage FAI Power. This change will be included in the 2024-25 edition of the NFFS Rulebook. Local event sponsors are encouraged to use these new rules in the interim.

The practical effect of this change is that engine runs for Vintage 7 models continue to be 7 seconds for a three-minute max in contrast to 10 seconds allowed in Vintage 6. These engines seem up to the task, and in light of the preamble to Vintage FAI as quoted earlier, this change may help provide:

“…competition where the rules have reproduced each time period in such a way as to make one period reasonably competitive with the others….”