Heinkel He 70 High Speed Mail Plane - RC Groups
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Dec 06, 2013, 12:03 PM
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Heinkel He 70 High Speed Mail Plane


Heinkel He 70 High Speed Mail Plane

From wikipedia: "The Heinkel He 70 was a German mail plane and fast passenger aircraft of the 1930s, that also saw use in auxiliary bomber and reconnaissance roles. It had a relatively brief commercial career before it was replaced by types which could carry more passengers. The He 70 was a leading design for its day, setting eight world speed records by the beginning of 1933."

It got turned into a bomber and was sent to fight in the Spanish Civil War. Eventually, it was re-designated He170 and did service in WWII.

Of interest is its eleptical wing, later to be seen in the Spitfire and the Japanese Aichi DeA "Val" dive bomber. It was the direct decendent of the He. 111.




It even made the cover of M.A.N. in 1936:



http://www.jitterbuzz.com/MAN_1936_11.HTML

NACA TM 746 can be found here:

http://digital.library.unt.edu/ark:/...9930094671.pdf
Last edited by TedD60; Dec 23, 2013 at 09:07 PM.
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Dec 06, 2013, 05:02 PM
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Sep 09, 2017, 01:31 PM
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I got interested in the He-70 last winter as a possible scale project. At the time of it's introduction in 1932, it was the fastest commercial design in the world. Considering how far behind the Germans were in aircraft engine design at that point, it was quite an achievement. As far as I know, there are no surviving examples of the airplane nor are there any factory drawings for it that survived the war. There are a number of artist drawings that exist, and they are incorrect in details of the fuselage construction.

Unlike most aircraft of that era, the He-70 fuselage skins were not riveted to bulkheads, at least in the tailcone behind the wing. They were only riveted to the stringers which themselves were riveted to the bulkheads. This allowed simple conic sections to be pieced together and butt jointed for a very smooth surface finish without lap joints or distortions of being pulled down to the bulkheads by rings of rivets. I have managed to find a couple photos of the fuselage in its construction fixture, and they clearly showed the bulkheads each mounted to vertical posts to hold them during the initial skinning of the sides. Since they are simulating of compound curve with conic sections of flat sheet metal, they terminate at different positions down the length of the fuselage.

The greatest difficulty is using search engines. Searching in English for scraps of info is limited at best. More success is found using German terms, which makes it rather tedious since much of their technical language has also evolved over the past 85 years.

The design itself and its development were very interesting. It was the first German design to use retracts, the wing was all wood with wood skins and it also changed as more was found out about high speed drag reduction. It was an inverted gull wing for ground clearance for the 3.25 meter prop on the direct drive BMW V12 engine. Because the geared drive engines were not yet available, this engine only turned about 1600 rpm.

The design first flew with no flaps on the wing, no fillets on the fuselage, and a pure elliptical platform shape (no notch at the trailing edge at the fuselage). The gear were either fixed or locked in the down position and the holes for the wheels were covered with plywood covers for the first flights. At that time there were no markings on the plane, but once the retracts were enabled it was marked with D-3 on the fuselage and wings. Later, flaps were added and it was then marked as D-2537, but still no notch in the wing or wing fillets. It was then remarked as D-UHUX and I believe sold to Lufthansa. This was also known as the He-70a.

The second one was the D-3114 which had the notched wing which was standard from this point on, however it was initially built and flown without the fillets. This was the He-70b which was remarked as D-UBAF.

One strange feature of these early commercial 70's was the canopy was offset to the left side of the fuselage, that only the pilot could see out of. As the design got shifted to military use, the greenhouse got centered and lengthen, export versions got a radial engine, and Rolls Royce traded some engines for one that they used to develop their RR Merlin engine for the Spitfire. The Germans even built one with a DB601, and both with the high hp fighter engines were quite fast considering their size.
Sep 09, 2017, 05:28 PM
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more He-70 images


Some more ...
Sep 09, 2017, 05:43 PM
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more He-70 imgaes from airwar.ru


These files are from the airwar.ru web site. These images download as .tiff files, but have been converted to .jpg format. They are large (>3mb) files.
Sep 09, 2017, 06:40 PM
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A picture from inside the pilot's area taken from the radioman' seat. Note the offset to the left where the upper torso of the pilot would be.
Sep 10, 2017, 10:46 AM
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He 70 in construction jig
https://books.google.com/books?id=66...0rumpf&f=false
Sep 10, 2017, 01:53 PM
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It is a good looking airplane. And it's advanced historical importance make it more enchanting, as a model subject.

The offset pilot was carried on into the He 111 bomber of early WWII. I got sit in one once and was astonished by the field of view. At this point, the entire the cockpit green house was also asymmetrical. IIRC, the British also used an offset pilot position in a number of it's bombers. Mosquito and Lancaster come to mind.

From a practical scale model standpoint, how does the prototype address the straight nature of aileron and flap LE's, as shown in the drawings? A straight line section imposed upon an elliptical surface means the thickness of the movable surface, has to vary, over its span. Think Spitfire aileron.
Sep 11, 2017, 03:32 PM
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ONE He 70 incident COULD have changed WW II - in the Allies' favor!


Dear Fellow RC-Groupers:

The PIPE Here...here's hoping that all the 1930s "P-aircraft" documentation "goodies" (for "Pietenpol" and "Polikarpov"-designed historic aircraft!) I've been posting in the threads of this forum have been, or will help, some RC Scale models of 'em as time goes on...

...but what not TOO many people might realize is, that ONE particular example of an "incident" with an He 70 mailplane on June 3, 1936, is quite likely to have changed WW II's events, AND eventual outcome, permanently in the Allies' favor on that date!

The main advocate for Nazi Germany to have a strategic bombing doctrine in any "upcoming conflict", AND to possess the heavy bombers to have the ability to execute on such a doctrine, was Luftwaffe Generalleutnant (Lt. Gen) Walther Wever. He took command of Adolf Hitler's then-new Luftwaffe as its Chief of Staff on February 26, 1935 and sponsored the "Ural Bomber" heavy bomber design competition by asking both the Dornier and Junkers firms to build usable four-engined prototype heavy bomber designs, the Dornier Do 19 and Junkers Ju 89 respectively, to see which design would be able to give the Luftwaffe a strategic bombing capability.

The "fateful day" of June 3, 1936 began as Wever was due to speak in Dresden's Klotzsche borough to a class of Luftwaffe air combat college cadets about his strategic bomber strategies, when he'd heard that a former World War I hero of the former Kaiser's German Empire had lost their life...he was getting a ride on an He 70 from Dresden back to Berlin, one that...just like the "incident" on October 30, 1935 that killed Les Tower and Ployer Peter Hill on that date when the Boeing Model 299 crashed for nearly the same exact reason...forgetting to remove the "gust lock" mechanisms before flight...was fated to end tragically for all concerned...

...and in the resulting crash of his He 70, Wever lost HIS life, ending any serious chance for the Luftwaffe to have a truly usable and effective strategic bomber force "in place" for WW II's offensive needs.

Just thought I'd touch on that "incident" that involved an He 70, that changed WW II's path a bit over three years before it even broke out in Europe.

Yours Sincerely,

The PIPE....!!
Sep 11, 2017, 10:03 PM
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As I read the story, Wever was not a natural pilot and insisted on flying his He-70 whenever possible. He was at the controls waiting on his "mechanic" and forgot to remove the aileron lock. His son went on to be an ace.
Sep 14, 2017, 12:46 AM
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NACA had an earlier report on the Blitz.

https://ntrs.nasa.gov/archive/nasa/c...9930090277.pdf
Sep 20, 2017, 04:14 AM
Scale Builder
Great thread with some good information on a rare and beautiful design. Certainly one that deserves to be modeled more than it has.


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