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Rotec R2800 in Germany installed on Klemm 25 d

Rotec R2800
Owner: Detlef Oberbach and Josef Schmitz
Aircraft: Klemm 25 d
Status: Flying as of March 2013

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Introduction to Detlef Oberbach's and Josef Schmitz's Klemm 25D Project:

Radial Powered Klemm Intro Klemm Kl 25 (source Wikipedia) was a successful German light leisure, sports and training monoplane aircraft, developed in 1928. More than 600 aircraft were built, and manufacturing licenses were sold to the UK and the USA.

General characteristics

Length: 7.5 m (24 ft 7 in)
Wingspan: 13.0 m (42 ft 8 in)
Height: 2.05 m (6 ft 9 in)
Wing area: 20.0 m² (215 ft²)
Empty Weight: 420 kg (926 lbs)
Max Take-off weight :
720 kg (1,587 lbs)


Max Speed: 160 km/h (99 mph, 86 kts)

650 km (404 mi.)

Service ceiling: 4,800 m (15,748 ft)

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Detlef Oberbach and Josef Schmitz Rotec R2800 Powered Klemm 25 d was completed and flying March 2013

8th of March 2013:

All involved in getting the Rotec Radial Powered Klemm finished Klemm 25 powered by Rotec Radial R2800.

Top Left First photo: all the people involved, L to R: Josef, Detlef, and Maria 'König.

Flights 2, 3 and 4 took place. We have become quite confident with both plane and  engine by now.

We plan to change the prop, to that end we are lucky to have a prop manufacturer at the airport who will give us different props for testing. We hope that the info is right that the prop hub is the same as the hub of the Rotax 912.
The plane is a Klemm 25 d, you can find some information about this type of aircraft on wikipedia. The Klemm came with different kinds of engines, the 'd' was with both radial and in-line engines.

Klemm 25 powered by Rotec Radial R2800.

6th of March 2013
Detlef and Josef
To: Rotec
Subject: first flight Klemm 25 Germany

Hi Paul,

The maiden flight took place yesterday and everything seemed to be OK. It took 30 minutes.

Paperwork for Rotec powered Klemm

October 2012:The Klemm 25D was covered, sent of to be painted, on return a final installation of the engine was completed. The Rotec Radial was started for the first time and ground testing of the engine commenced on home base EDKA ...

Klemm 25D off for a paint job
Klemm 25D comes home after a paint Job
Detlef and Josef do some final checks before a first run
First start of Rotec R2800
Klemm 25D ground testing the Rotec Radial R3600
off for paint job
back from paint job
final checks for 1st start
Ground tests at EDKA

2nd of August 2012: Engine arrives and is test mounted.

Rotec R2800 fits perfectly to the Klemm 25D
... Rotec R2800 is a perfect fit!

June 2012: A critical event - testing the wings with 1,5 tons on each side.

Klem Wings Load Test
... each bag of mortar weighs 25Kg

February and March 2012 were devoted to the fuselage frame.

Klemm 25 Fuselage Construction
Kemm Fuse with Maria
February Fuse bulkheads
Fuse bottom view
March Maria Takes a seat

By the end of January 2012 the framework for the wings and rudder are completed

Klemm Rudder - difficult job
Klemm rudder
End of December 2011 and January 2012 were devoted to to the rudder

Ribs and Spars for Klemm 25D Wing Spars Klemm 25D Glueing Klemm25 Wing Spars Klemm 25 Wing Assembly Nose ribs for Klemm 25D
November was devoted to making wing spars. By December we were doing a lot of gluing and assembly including the nose ribs

October 2011:

Pine for Klemm 25
Detlef (Right) guides the first plank for Joseph (left) to saw

Detlef and Joseph built the Klemm from scratch starting with choosing an appropriate tree trunk of  Scandinavian pine in October 2011.  

Building the plane was conducted on the basis of a more or less complete set of copied plans (rather less than more ) and hundreds of pictures taken during the restoration of an original Klemm which were given to us.

Detlef has already built 10 RVs, but has never worked with wood. Josef used to be a model carpenter and is the technical director of a foundry now, but does not even have a pilot's license. Together they managed to finish the Klemm on the basis of their respective knowledge in a little more than a year. A good team!

- Construction begins with the first cuts into the Scandinavian pine

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