Hansa Jet: the lost German jet (now RC!)

The Hamburger Flugzeugbau HFB-320 Hansa Jet was an all-metal, twin-engine, 10-seat business jet that was built by German aircraft manufacturer Hamburger Flugzeugbau between 1964 and 1973.
The most notable feature of the aircraft was its forward-swept wing, which was mid-mounted in the fuselage. This arrangement allows the wing spar to pass through the fuselage behind the passenger cabin without decreasing cabin volume. As of 2011, it remains the only civilian jet ever to use a forward-swept wing.

The jet was last known to fly in 2009 with the Luftwaffe (German airforce)

The jets interesting shape, uniqueness and on top of all the Forward Swept Wings appealed to my sense of adventure and after much hunting around I found no evidence of there ever being an RC model of it, this sparked my build instinct :p and so started this project.

The first thing I set about was finding a 3 view and after much searching I found this 3 view and a reference drawing

So after scaling up and much math I decided upon a 44" wingspan jet and set about building it.

First I cut floor panels and added formers, shortly followed by some skin panels.

Then I began building the wings, sizing up and guesstimating the correct size and shape of the control surfaces, placing spars, ribs, so on so forth.

I then began cutting the rudder and building the elevator,

The next step in the process was to build the rear half of the jet in order to support the tail.

Then I set about building the lower half of the fuselage and squaring-up the fuselage and wings.

After much thinking I had settled on the fowler method for hinging the flaps and mounted them and they're hinge fairings.

I took the liberty of building a scale cockpit too while I was at it

The next step was to carve and gradually sand and carefully shape the two tip tanks to which where then attached to they're respective wing-tips

When my fans and landing gear arrived I immediately set about installing my retracts so I could set the bird on her feet!

I then begun the task of soldering up mating up her twin 50mm Changesun 11blade fans to the 50A Red brick ESC's ( I have only ever had good results with red brick ESC's) and soldering on the connectors.

Afterward I mounted the power system and took some beauty shots! ( how artsy! )

there is some ply wood mount plates for the landing gear hidden within the foam Superstructre and can be barely seen when viewed from above 

The next step was to build and mount the slat mechanism, which was relatively simple and had good results.

Now that my main gear was in I set about building the belly fairing ( that the gear retracts into), I started by first placing formers and then a few stringers to build up the shape of the belly fairing,

When my carbon arrived I set about bracing the wings to prevent too much wing flex and also to hold the correct amount of dihedral.

After more beauty shots I weighed her to work out roughly what the wing loading would be and to find out roughly what the AUW would be,

The two turnigy 2200Mah 3s 30C Lipo Flight packs

Total is looking at around (3.5lbs)

Seems like the wing loading will come out at about 20oz/sq.ft so still pretty light

Still gotta add nacelles and remaining skin panels
Being curious I took her out for a Taxi test in the midst of the night and begun a few high speed taxi runs to which on one she hopped into the air ( butt clench moment as she doesn't yet have her flight controls) flew a few feet (at 40% throttle) and settled down gently in the short grass...

here is a short video of the Second Taxi test 

it was mostly filmed at 60% percent throttle and above  

she seems pretty nippy and i absolutley love the sound of these Fans!! 

they have a nice Whoooooooosh....

im beginning work on the nacelles this weekend as i have printed and cut-out the templates :)

also in other news an engineer freind of mine at Teledo Airfeild managed to snap a few pics of the last surviving US Registerd Aircraft (it was a Grand Aire Cargo Aircaft)

More progress

31/3/14

Got some major skinning work done and built the nacelle framing 

i closed up the wings and added the balsa leading edges, the wing is ten times stiffer now (i can pick up the aircraft fully loaded by the wing tips and the wing seems plenty stiff torsionally) 

i then set about CG'ing the Aircraft 

With the CG Set on the main Spar the batteries sit just infront of the Wings LE which works out perfectly for me.

i then began sheeting the nacelles with some 3mm Depron 

i still have yet to add the intake lip but id say it looks good so far 

i then set about reshaping the tail cone to better resemble the real thing 

i still need to figure out how to make the bump on the tail cone after sheeing the tail and add the ventral fins 

i then began cutting the second nacelles skin panel 

a little artsy beauty shot showing just how big she is 

more updates to come soon so stay tuned for the completion and up and coming maiden!

Keenan smith