1:4 1928 RRG Professor

[ErichS]

I came on this thread a bit too late. The Rhȍngeist was the prototype for the Professor built by Schleicher and was intended to replace the RRG Falke. It arrived at the Wasserkuppe in 1928

Kronfeld made 4 very importants flights with the "Rhȍngeist":-

- 30th April 1928: (Probably) the 1st Variometer flight in Gliding-History; starting at the Kuppe with a flight to the Weiherberg and back to land at the Kuppe at the same place he started. The Vario was built into the instrument panel and fitted horizontally and hidden under a leather flap, Georgii, Lippisch, Kronfeld and Nehring knew of it and how it worked.

- 6th August 1928: The Himmeldung (a mountain at the Rhoen) flight; the first official Vario flight. A handful people of the RRG were involved, including Hirth. For the international scene the Vario is a "german secret" untill 1930 when Hirth travelled the US and Kronfeld toured Britain. See photo attached of the Vario

- 14th August 1928: Kronfeld's Record flights at the Rhoen Competition; Duration Flight: 7h54min - Course record: 41 km - Altitude record: 660m --- winning the 9th Rhoen.

- End of January to about 20th Feb 1929: The Rax-Expedition; first international RRG Tour (to Austria), for the first Alpine Expedition. The Tour was lead by Fritz Stamer. Kronfeld made his important flights on the 4th and the 12th Feb.

In 1929, Kronfeld moved on to the Wien, which was basically an improved Professor. The Rhȍngeist was overhauled and reworked, but it made no further records.

I have several photos , including the Rax expedition and a 3-view depicting the cartoon image of the Rhȍngeist which was on the fuselage. Apart from the Vario, nothing seems to be known about the instruments on board. The 3-view can be found here: https://scalesoaring.co.uk/VINTAGE/3.../3-views3.html

Was looking at the different planes in the link you posted and saw this crazy one (Kupper Ku-7). The wing tips twist to turn and also can go up and down to act as flaps.

[Tango Juliet]

There are several "interesting" designs on those pages.

[ARUP]

Yeas... that Ku-7 is on my 'list'!

[Tom]

Was looking at the different planes in the link you posted and saw this crazy one (Kupper Ku-7). The wing tips twist to turn and also can go up and down to act as flaps.

Markus Frey built one.....1/2 scale..... http://www.ig-albatros.ch/baubericht...er-ku7-mst-1-2

[ARUP]

That's a cool model! I wonder why he didn't paint it gray like the full scale?

[ARUP]

All day was used to put ply on the fuselage. A Coverite iron set on 'hotter than...' was used to pre-bend ply as needed like around the pylon to fuselage junction. The iron was used kind of like a paint brush to heat the ply while pressure exerted to curve it. My fingers were getting a little hot, too! One section of ply was fitted but not glued to the nose so that lead ballast can be added if needed, later, after the model completed. A stereo pair of pics are shown!








More later. Time for supper!

[ARUP]

More plywood skinning! There isn't much to show except the progression of the skinning process. Paper and card patterns were used before cutting the ply. Then the ply was cut and sanded to fit. two 4' x 4' sheets of ply were used with ~1' x 1' left over. The first two pics are a stereo pair.









More...

[ARUP]

'Andmoreagain' by Arthur Lee. More skinning! It is finished except for the tail end. The fin and skin have to get built onto the fuselage before the plywood skin can get totally done. The last pic of the cockpit is similar in composition to the one VinceC posted.







On to the tail!

[BobM]

Really beautiful work Michael !

[ARUP]

Thank you very much, Bob! Are y'all staying warm up there? We had single digits a couple of weeks ago, including some minus temps, it went up into 20s and 30s, will be in 60s end of week then snow coming! No wonder Native Americans never stayed here permanently... it drove them crazy, too!

[lenb]

All I see is a beautiful floor?

Oh, wait..... There is a something sitting there... oh, sorry now I see it.
Nice color match to your surroundings. Love your workmanship Michael.

[ARUP]

Thanks, Len! The fuselage wasn't too bad but the fuselage to pylon transition was 'ticklish'??? An 'expletive deleted' could be used to describe the effort! lol

[Dion Dunn]

Beautiful work Michael. Can I put in an order for a nice end table with inlays next please?

[ARUP]

Sure... 1/4 or 1/3 scale? Thanks for checking in the build!

[ARUP]

Music wire was cut, bent, cleaned, soldered (Stay-Brite brand), cleaned again then painted to form a tail skid. It inserts into a 1/4"marine ply block inside the fuse and attaches to a bass block in front of the fin post. The fin is getting built.





Dobranoc!

[kjkavaney]

Can't wait to see this beauty next season Michael....inspirational..
kevin

[ARUP]

Me too! lol The fin and rudder were started. These are getting built 'clam shell fashion' so the flat hinges can be more easily installed. Bass is being used for the fin TE and rudder LE. It would be a little difficult making accurate slots for them especially since the rudder will be removable. To make that happen the hinge pin has to be guided by a tube. The is no access to the hinge pin from below because the tail skid is in the way so the pin and its guide tube are fitted almost the whole length of the rudder. This has to be perfect!







The basic fin structure has a balsa LE added to it. It is shown tapered... like the drawing. There is no way to sand a nice round shape to it because there isn't thick enough wood at the top. The off-cut was glued back onto it. See Kevin... another 'almost scarph' joint! lol

[ARUP]

In the previous post's last pic is the fin and LE halves of the rudder. These halves were grooved to receive the hinges just like what was done with the fin's TE. You can see this and how it works in the next picture. The rudder's LE stock was tapered from just above the topmost hinge up to the tip. The rudder LE was laid down to the board so that ribs and ply laminate outlines could be glued in place. After the parts were dry everything was sanded and re-stained... just for grins! The aerodynamic balance portion of the rudder will get built after the other half of the rudder is done. Ply skin will go on these parts, partially, too.





Don't ask me why that one picture is so big because I resize all photos the same. Danged computers.

Buna notg!

[Swiss1]

5 days since an update "Jelly", whats happening

SCCAAA TT TN

[ARUP]

Here it comes!

[Swiss1]

5 days since an update "Jelly", whats happening

SCCAAA TT TN

[ARUP]

Ibid lol

[ARUP]

Jeremy... here it is! Work gets done every day but sometimes there isn't much to show for it. The aerodynamic balance portion of the rudder was made of balsa. The cross section of it had to match that of the fin at the gap. There was lots of trial and error sanding going on here! A taper was sanded at the rudder bottom end to match the skid fairing which will get built soon. Another picture shows the fin and rudder connected with the hinge pin in place. There will be a little tube fitted into the rudder to receive and capture, via an interference fit, the 'hooked' end of the pin. The rudder horn is made of 1/16" music wire Stay-Brite soldered together. The ends of brass tubes were flattened then drilled to receive rudder cable shackles. These tubes were then epoxied to the music wire horn. They could be soldered in place but I was lazy and didn't want to go downstairs into the cold garage and fire up the torch. The horn was let into the rudder LE at the proper height relative to the cable exits on the fuselage and a balsa block was epoxied in place to hold the horn. The fin and rudder will get some 1/64" ply later. The gap between the fin and rudder was filled with tapered bits of balsa. The second to the last picture shows the bits on the left side. They have notches to clear the hinges. These bits can be seen in the last picture pinned in place as the glue is drying as I type! I hope to start the stabilators this weekend.









Oiche mhaith!