| Tail Number / N-Number | N21GR |
| Manufacturer | ROBINSON DENNIS R |
| Model | ROBINSON/PITTS S1S |
| Year Built | 1984 |
| Manufacturer's Serial Number | DR-1 |
| Aircraft Type | Fixed wing single engine |
| Category | Land |
| Builder Certification | Not Type Certificated |
| Number of Seats | 1 seat |
| Weight Class | CLASS 1 (Up to 12,499 pounds gross take off weight) |
| Engine Manufacturer | LYCOMING |
| Engine Model | 0-320 SERIES |
| Engine Type | Reciprocating |
| Number of Engines | 1 engine |
| Horsepower | 180 hp (134 kW) |
| Type of Registrant | Co-Ownership |
| Owner Name | ROBINSON DENNIS R |
| Other Names |
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| Street | 1310 E 93RD ST N |
| City | VALLEY CENTER |
| State | KS |
| Zip Code | 67147-9127 |
| Region | Central |
| County | Sedgwick County |
| Country | US |
| Fractional Ownership | No |
| Airworthiness Classification | Experimental |
| Airworthiness Date | 1985-05-05 |
| Certificate Issue Date | 1984-08-29 |
| Last Action Date | 2020-10-21 |
| Expiration Date | 2028-03-31 |
| Status | Valid Registration |
| Mode S Code | 50333717 |
| Mode S Code Hex | A1B7CF |