• 
• 
• 

• 

The "Bumblebee"«By
Mrs. Stamer.
Referring to the editorial in the "Flugsport" of 25.11.31 and to the small note that the "Hummel" flew from the Wasserkuppe to Griesheim, I would like to tell you a few things about the "Hummel" here
.
There is a lot written and a lot of talk about a so-called people's plane. So much so that it soon came to the point that someone who spoke of the people's plane was looked at shyly from the side
, because one was prepared for completely different things.
After there was once a competition of small and light motor aircraft on the Wasserkuppe, the matter fell asleep again in Germany. Unscathing people have come
together and argued about two-stroke or four-stroke, water or air cooling, high-wing or low-wing aircraft, but always agreed in
a common grumbling about the evil engine industry, which is so backward, about the evil DVL, which would probably cause trouble, and about
the evil authorities, who should make freer regulations for such aircraft.
It should not be denied that these last three points would be more favourable for the construction of people's aircraft, so that there would be a strong stimulus, but
what is not is not.
Gliding actually teaches you to look for a way where there is none.
3 years ago there was also a group of such complainers together on the Wasserkuppe and I was in the middle of them. It was necessary to convince a representative of the
authorities that the existing provisions should not apply to the imaginary aircraft.
The answer was simple and hit the nail on the head: "Build such an airplane and we'll see!" I didn't ask the engine industry and the DVL anymore
, the answer would probably have been similar. I was given permission to develop a small powered aircraft in the workshop of the flying school.
What was the aircraft supposed to do? It should fly, just fly, that was point 1. It was not to be fully aerobatic, it did not need to take part in the Coup Schneider
or the European sightseeing flight. Who should fly the plane? Anyone who can fly and pious wish, if possible also someone who is an
experienced glider pilot and also everyone who cannot pay RM 80 for the flying lesson. Where should the plane fly? If there is no other way, only around the
airfield, i.e. within the airport zone.
How much should the plane cost? And that was point la. If possible, nothing ferments! Why? So that it becomes a people's aircraft.
Who is to build the aircraft? Our glider industry and if possible the club itself, which can already build, because point la demands that!
So what did the plane have to look like? High-wing aircraft, because it comes directly from gliding and the glider pilot feels more comfortable on the high-wing aircraft. view of the
wheels, then you make less breakage. A bit sleek, otherwise you won't enjoy it. Even if an airplane is severely undernourished in terms of engine horsepower, it should
not look like a wild dovecote. Timber construction — because of self-construction and repairs.
After this was clarified, the necessary was created with the help of paper and the big bearing thumb. And now the engine! Rich people look on the left of the wine list,
others look on the right, where more detailed information is given in regard to marks and pfennigs. That's how I came up with the 2-cylinder DKW engine. Kg/hp is not so good,
but kg/mk. satisfied, and hp/mk. is quite good. Where were the results available? Martens-Kegel-Lippisch. All experiments with air-cooled DKW engines and all
cooling difficulties. In the car, the engine runs water-cooled until the pistons are gone. Extra weight? Yes, but "safety first!" — In the spring of 1929, the bird was standing.
Radiator! — Thermo-Syphon, so on top! How big, how much content? Try! The engine was equipped with a reduction gear, as used by DKW for stationary pumping
systems. Engine tours 3000 to 4000. Reduction ratio 1:2.5. Lippisch faithfully helped with everything. And then the bird stood
on the Reizner slope and roared around on the ground, growling bitterly evil. The box had lost the name "Hummel" — and I had the name
Hummelvater. A new propeller was built and the stems were covered and lo and behold, the humming became friendlier and the ground remained under
me. Not long and not far, but still. Then the Pelzner slope was left by air, the cooler began to boil so that one sat as if in a
Roman steam bath, the altitude was lost and the landing took place in the southern slope foreground. This happened several times and would have gone smoothly every time if
I hadn't rolled into a ditch, with the propeller saying goodbye. The third propeller was good and a new radiator was ordered. In the meantime it had turned out that the machine would
do well with a little more surface area and so the wings were sawn through and 80 cm into each surface. Now everything went quite
well, but the reduction gear was not reliable, and it was now necessary to call on the engine company again. In the winter of 1930/31, a special gearbox was built and delivered by
the DKW company. At the same time, the DKW company kindly exchanged our engine for a higher
compressive sports engine.
With this engine, pleasing results were achieved immediately and the actual testing of the aircraft began. The new gearbox, the new radiator and the
Propeller III proved to be excellent. According to the flight log, the aircraft carried out a total of 63 flights in 1931 under 19 different pilots. In order to hear quite
a lot of opinions, we put quite a few guides on the machine, all of them were enthusiastic. The machine flew
to an altitude of 2500 m and was able to carry out a cross-country flight from the Wasserkuppe to Griesheim near Darmstadt in 3 hours, despite 501 km of headwind, without a stopover on the basis of a permit from
the RVM. The machine has a
normal speed of 90 to 100 km, a landing speed of 30 to 35 km, carries fuel for 5 hours of flight, has a remarkably short take-off of 100 to 150 m even in calm conditions and in
bad places, does not need to be pushed, is very pleasant to fly and costs,
factory-made, after several hours.ca. RM
In the winter of 1931/32 a second engine with some improvements is to be built, and for this type licenses are to be issued and the
drawings are to be submitted. The machine, which is of course single-seater, has a flying weight of 300 kg, which corresponds to an empty weight of about 200 kg.
The two-stroke engine has the advantage of the greatest simplicity. There is little to maintain on the
engine and once it has suffered, you will probably buy a new engine before you start long overhaul work.
Now you can continue to argue about the three points mentioned at the beginning, but it's no longer a dispute about Kaiser's beard!
Anyone reading this does not believe that the Wasserkuppe has become unfaithful to gliding. Gliding must not and will not suffer from a development into a people's aircraft from
gliding.
As a small proof that this engine was developed on the side, the result of the flying school in the summer of 1931 may be cited.
A total of 325 students trained and passed 115 A, 100 B, 132 C and 37 official glider pilot examinations on 4992 flights. 35 students were trained as
tow glider pilots * in special courses in Griesheim near Darmstadt. As is a matter of course for the Wasserkuppe, as many types
as possible were flown and the "Professor" was also used quite often. Flights of more than 5 hours, 800 m take-off elevation and 20 km distance were carried out on it.