When I was just a 14 years young boy I saw
them flying at a model-air show in Germany : Lawn-mowers, build in wood
and styro-foam, equipped with a 10-cc-motor and a tuned pipe. They were
loud, fast and very impressive – in the eyes of a young boy like
Today, 20 years later, I browsed on a lazy
Sunday afternoon in the World Wide Web. Suddenly – I hope nobody
will ask me how – I reached the website of a small model-shop
in eastern Germany, named Flugwerft Brendel (www.flugwerft.com).
That company offered a kit for a flying lawn mower, nearly the exact
same model, which I’ve seen as a young boy. The mouse click on
the order-button was almost instantaneous and several days later I received
a package with a lot of plywood- and styro-foam-parts. While studying
the plans and the parts, old childhood-dreams were coming true. But
that the model will be as big as the plans were exciting, I haven’t
forgotten this over the years.
Philipp Gardemin (Aufwind's editor) show this
lawn mower is really a full scale model !
You can see a small
video by switching
(630 ko, format wmv)
The central section of the flying lawn mower
is the wing, with an S-profile and two big flaps on the trailing edge.
Built with plywood-ribs, pine-wood-stringers and a balsa-planking; it’s
a very stable and impressive piece of wood. The RC-components, the battery
and the motor are included a big plywood-box in the middle of the wing.
The design-elements, which everybody can see that this is a flying lawn-mower,
are made from foam and glued on the central-section with white glue.
Three servos of the standard-class are operating the two flaps with
a delta-mixer and the front-wheel. The whole model is moving on three
wheels of 70 mm diameter. The four wheels on the side of the lawn-mower
are just dummies without any function. The big handle on the back of
the lawn-mower is made from 6-mm-balsa. It looks very realistic, but
it’s very susceptable to breaking. If the handle has some aerodynamically
functions I haven’t found out until yet – and I’m
not willing to test it! The colour-scheme is scale: The famous German
company Wolf-Garten is using the same colours on their lawn-mowers.
Acryl-colours and “Orastick”-foil were used.
Two big flaps are mixed for elevator and roll
The lawn-mowers 20 years ago were flying with
10-cc-motors. Today it sounds better with an electric-motor. I used
a “Compact 490”-outrunner from Graupner with 18 cells and
a 12”x6”-APC-prop. To my biggest surprise it was no problem
to fix the centre of Gravity at the right position and the flying-weight
was exactly in the area which the manufacturing company suggested before.
But there was a final question : How will that
crazy thing fly ? On one of the first warm evenings in Germany I put
that flying lawn mower on my grass-airfield and gave it full power.
Much earlier than I expected the model took off and climbed fast and
in a stable manner into the sky. My surprise was such that I nearly
forgot to control it. The first round gave me a good feeling, how the
rudder function is : smooth but direct, never critical. For two minutes
I flew that crazy lawn mower around the airfield. All spectators were
more than amused by the flight-image and the sound, which the model
sent back. The first landing was no less impressive : With 30 per cent
power I flew the lawn-mower to the strip and with a deep “bump”-noise
the flying lawn mower was back on earth. My old childhood-dream came
Each time on the field, this simple lawn-mower
make the show...
Several days later I visited
an electric-flight meeting with 50 pilots and several hundred spectators.
And what shall I say : Between the most expensive and biggest model-airplanes,
my cheap and simple lawn-mower stole the show. I flew many more times
on that weekend – each flight was a show stopper !
a glance :
Wingspan : 780 mm
Length : 900 mm
Height : 950 mm
Weight : 2990 g
Motor : Compact 490, Graupner
Battery : 18x CP-1700, Sanyo
Flight-time : 3 minutes
Propeller : APC 12”x6”
Kit-price : 49,- Euro
Address : Flugwerft Brendel,