Report on the Graupner Best.-Nr.1880 Rotary Engine

【Report on the Graupner Best.-Nr.1880 Rotary Engine】

Since the launch of our Wankel rotary engine (hereafter: RE) “NR-20_SERIES”, we have received many inquiries from customers asking, “The Graupner Best.-Nr.1880 (37.41cc RE) (hereafter: RE38), released in 1993, is marked “Made in Japan”, but is this manufactured by NITTO MFG.,LTD.?
Until now, we have not made this public, but in response to the increasing number of inquiries in recent years, we would like to officially report the following.

　　　　　　　▲Fig.1 Prototype of RE38

1) 【About Graupner’s RE38】

■The RE38, released by Graupner in Germany in 1993, is a product in which our company (NITTO MFG.,LTD.) has been consistently responsible for all manufacturing processes, including consideration of processing methods and materials from prototype to mass production.
Although there was a certain demand for this RE38, production has been discontinued.
At the time, we conducted our own tests on the RE38 and found that there were areas that needed improvement, especially in idling and durability.
In addition, we found many areas that needed improvement in terms of design, such as the trochoid curve, rotor outline, intake and exhaust, and plugs, and we determined that fundamental improvements were necessary.
In particular, the RE38 had a point to improve with airtightness because the apex seal was a one-piece type.

▲Fig.2 Main parts of RE38

2) 【About Independent Development of the “NR_SERIES” by NITTO MFG.,LTD. 】

■ Our own redesign and technological innovation (development of our Wankel type RE) After production of the RE38 ended, it was not reproduced or resold even after several years had passed, and full-fledged small Wankel type RE disappeared from the RC market.
So we started our own development to supply a more authentic Wankel type RE to the RC market.
Taking into account the issues with the RE38 mentioned above, we reselected materials for all parts, including the housing and rotor, and started designing and developing from scratch with the aim of improving power output, durability, and practicality.
As a result, we were able to solve all of the issues with the RE38 and complete the “NR_SERIES”, which we currently mass-produce and sell.
With our “NR_SERIES”, we actively attempted processing that was considered difficult with the RE38.
In particular, the apex seal has a two-part structure to improve airtightness.
During the prototype stage, we made a wide range of technological innovations and obtained patents.
We are proud to have designed, developed, and manufactured the product faithfully to the theories of Dr. Wankel, who invented the Wankel-type RE.

▲Fig.3 Technical Comparison　　　　▲Fig.4 NR-20 series

3) 【Completion of “NR-20_SERIES” by NITTO MFG., LTD.】

■ User evaluation of NR-20_SERIES

Through our independent and unique development, the high-performance small Wankel type RE “NR-20_SERIES” which currently manufacture and sell, was completed in 1997.
The “NR-20S” (successor model: NR-20αP) cleared the initial objectives of “durability, idling stability, output, low vibration, practicality” and was featured in the June 1998 issue of “Radio Control Technology” as an RE capable of acrobatic flight.

▲Fig.5 Radio Control Technology, June 1998

▲NR-20αP flight video

Then, in response to requests from helicopter users, we developed the helicopter version of the NR-20H (successor model: NR-20αH), which was introduced in the March 1999 issue of “RC Technology”.

▲Fig.6 Radio Control Technology, March 1999

▲NR-20αH flight video

4) 【The Future of RE NR_SERIES of NITTO MFG., LTD.】

■ Finally

NITTO MFG.,LTD. will continue to develop, manufacture, and sell small rotary engines with excellent reliability and performance, making use of the unique technology and know-how we have cultivated up to now.
We look forward to your continued co-operation and support.