Powered Horten H IX V2 model

constructed by Erik van den Hoogen and friends

The Horten H IX V2 model coming in to land

Picture of the Horten H IX V2 model. All photos © Erik van den Hoogen

Back to Huib's Aviation Books and Flying Wings Page

On this page a presentation is given of some data and a selection of photos of the powered model of the Horten H IX V2. The model is build by Erik van den Hoogen and friends and they kindly supplied the photos and data shown on this page.
For further information Erik van den Hoogen can be contacted at: erik-rc-electric@hetnet.nl.

Specifications of the Horten H IX V2 model

The Horten H IX V2 is built to ¼ scale. The wingspan is 4.2 m and the centre rib has a length of 1.86 m and is 29 cm thick!
The nose wheel has a diameter of 200 mm, the main wheels have a diameter of 165 mm.
Two AMT turbines delivering 17 kilo's of thrust together.
Estimated speed more than 150 km/h.
Weight 20 kg (18 kg empty).

Construction of the Horten H IX V2 model

Wings and centre section
After completion of the ground plan, all the ribs were drawn and the wooden form with the right twist for the bell-shaped lift distribution was build. The wing was build in this form in one piece to secure that the right half was exactly the same as the left half. After placing ribs and spars in the form, it was cut in three pieces, two outer wing panels and the centre part. Spars, wing attachment points, servo leads and finally the top sheeting were glued together. On this upper side, a counter form was build to make it possible to turn the whole model upside-down and then the wing was turned on its back to be placed on the bottom sheeting. In the mean time the undercarriage parts were constructed.

The Horten H IX V2 under construction

The Horten H IX V2 under construction

Front view of the Horten H IX V2 under construction

The Horten H IX V2 under construction

Now the next important piece of work was starting, the building in of the two turbines. They are mounted inside the wing, so a long exhaust pipe was needed to guide the hot gasses through the center part. A double pipe was made out of thin stainless steel, 0.07mm as the inner pipe and an aluminium outer pipe from a 0.25mm sheet. Both pipes were spot-welded. On the inner pipe, a venturi-shaped inlet was constructed, which was attached, adjustable to the outer pipe.
The turbine was mounted inside an epoxy/kevlar duct. The turbine, the duct and the two pipes were mounted on an aluminium strip so giving a one piece propulsion unit, which can be put in the inside of the centre part of the model. This was done to have easy access to the turbines for maintenance. Also in case of a crash, the turbines are protected. After building in the two turbines, the top sheeting of the center part was applied.
Also the three legs of the landing gear were built in as complete units so that they can easy be removed. The air supply comes out of a soda-bottle of 1 litre and is controlled by a Robart-valve.
The RC-set is made up from 9 digital JR servo's (8411 and 8301) and a S-PCM receiver R1000. Two 5 cell 1400 mAh Sanyo NiCD battery are used in combination with a DPSI, a hi-tech power regulator. The transmitter is the JR PCM-10X, with the new S-PCM code, a handheld transmitter with a lot of possibilities in mixing the separate channels. The range of this set is great, more than 150 m with the turbines running and the TX antenna in! The antennas on the model are 1.2 mm piano wire, sticking out just after the canopy.
Nearing completion, a vacuum-formed a clear canopy was constructed.

The mainwheels of the Horten H IX V2 model

The nosewheel of the Horten H IX V2 model

Close up of the nose and left turbine of the Horten H IX V2

The cockpit with 'Herr Scheidhauer Junior'

Camouflage and markings
After sanding, filling etc, it was time to put the model in silk. The whole structure was doped once and then the large pieces of cloth could be applied with dope. The dope was first painted on and then rubbed-in to get a good contact between the wooden skin and the silk. After two extra layers of dope, the model was painted in the original colours, top "Violet-Grau" and bottom "Hell-Blau" The interior of the landing gear bays was painted "Hell-Grau". After applying the markings, text block, panel-lines etc, the whole model was sprayed over in a semi-gloss clear paint to make it fuel proof.

Further development and first test flight

Final preparations
Now there was a model, empty weight 18kg, with a problem. The centre of gravity was very far forward, with the big nose gear in, it was very nose heavy. The C of G was almost on the neutral-point, normally very dangerous. Calculations showed that this was caused by the two big holes in the leading edge for the inlets of the turbines.
Transferring the pump battery and both receiver battery's to the back, a still little nose heavy model was the result.

First flight
On the 25th of May 2001, some 2 years after construction of the model was started, the Horten H IX V2 model took to the air for the first time.
The weather was very good, a soft breeze from the east and lots of sun. After the range check the tanks were filled again, the turbines lit and with shaking knees full power was applied. In 30 m it accelerated to the point of lift-off and with still full power it climbed at 30 degree into the blue. Throttling back was necessary because the model was still going faster. Testing aileron and elevator response, the flaps were tried to see what moment it would bring: nose down, more than could be compensated so the flaps went up again. The nose gear produces a lot of drag that can nicely be compensated by a little up elevator. After a nice low-pass, the landing was on. Due to a incorrect C of G, the landing speed was very high. When the model touched down, the nose wheel broke of and the model came to a stop on its nose. What we learned was that on landing, the angle of the wing is less than the 7-degree during take off.

The Horten H IX V2 model in flight

The Horten H IX V2 model in flight

The Horten H IX V2 at the Scale Treffen in Würzburg 2002

The Horten H IX V2 at the Scale Treffen in Würzburg 2002

The Horten H IX V2 at the Scale Treffen in Würzburg 2002

The Horten H IX V2 at the Scale Treffen in Würzburg 2002


The Horten H IX V2 model project members

The following people were involved in this project:

Further information (and photos) can be found at the: Dutch-Horten Internet Site