National Free Flight Society

One-Design Rubber Event

In 1998 Bill Vanderbeek instituted the popular One-Design Gas event, for ubiquitous small gas designs such as the Starduster, Mini Pearl and Ramrod. Borrowing from Bill’s great idea, the 2016 NATS featured a One-Design rubber model, My Coupe, in honor of Bill Vanderbeek. This super-simple Coupe design was the 1972 Model of the Year, is easily built of balsa, and equally easy to fly.

The rules for NATS One-Design Rubber are short and simple, and are designed to encourage maximum participation by modelers young and old, novice and expert.

2023 NATs Rubber One-Design
Any documented Coupe D’Hiver design that was airborne before 1/1/70. There are a few Coupes published in the early 1970s where the magazine text says they were flown prior to 1/1/70…in that case the design is legal for this event. Contestants are responsible for providing eligibility documentation.

1. Models must be built to plan. No variable geometry flight surfaces even if shown on original plan.
2. Original airfoils and spar placement must be used. No D-boxes or geodetic ribs unless used on the original.
3. Wood sizes may be increased but not reduced.
4. Carbon, kevlar, fiberglass may be used very sparingly to increase strength in key areas. Don’t overdo it; CD’s discretion on this.
5. Rolled tubes only if used on the original design.
6. Any covering may be used.
7. Takeoff gear may be omitted.
8. Prop must not exceed plan diameter.
9. Prop type must same as original (one-blade or two blade folder, or freewheeler). Any type of prop hub may be used on folders except no DPR or IPR.
10. Minimum 70g empty airframe weight
11. Maximum 10g lubed motor weight
12. 3x120s maxes, then fly-offs increase by 1 minute each flight. No Rounds.

NATS One-Design Rubber Rules

1. Models must be built to the published plan and all wood sizes retained.
Spars may be moved. Carbon and kevlar are not allowed.
2. Propeller not to exceed diameter on plan. Wire and metal hubs may be
used in place of wood hubs. For P-30 AMA rules apply on plastic props.
3. No variable geometry (auto stab/wing/fin) and no instant or delayed
propeller start.
4. No restrictions on covering material.
5. No builder-of-model restrictions.
6. Minimum empty weight: 70g for Coupe, 40g for P-30.
7. Maximum rubber motor weight: 10g lubed.
8. No ROG required; takeoff gear may be omitted.
9. Flight rules: Six attempts allowed to achieve 3 flights, 120 seconds
maximum apiece. Attempt is 20 seconds. Flyoff 1 is180 sec. Flyoff 2 and
ensuing are 240 sec., until a maximum is not achieved.