Blohm und Voss BV-141 (oz16034)

About this Plan

Blohm und Voss BV-141. Radio control sport-scale model. WIngspan 54 in, for .40 engines.

Quote: "Blohm und Voss BV-141. Go asymmetric with Ken Sheppard's 54 in wingspan replica of the German light bomber.

Love it or hate it, the eccentric layout of the BV-141 is, to say the least, different. It's been on my build list for a long time, awaiting the time that I felt confident enough with my flying ability to handle the anticipated problems with the asymmetric configuration. Perhaps I should have waited a little longer, but more of that later!

The full size aircraft was conceived at a time when aircraft design in Germany tended to be derivative based. Imagine the raised eyebrows and derisory sniggers when the radical design was submitted for government funding. It says a lot for the charisma of the designer, Richard Vogt, that he persuaded B&V to build three prototypes and ten production aircraft, despite Luftwaffe support being denied.

It was, however, a surprisingly fine-handling aircraft and as an observation/light bomber it would probably have been very successful, had B&V been able to overcome the German High Command's prejudice against the unusual. I found the challenge irresistible, to reproduce the character of the original and make it fly well.

Made mainly of blue foam, the prototype model weighs 4.1/2 lbs. With a wing area of 520 sq.ins., the wing loading of 20 ozs./sq.ft. gives it a sprightly performance with an OS4OFP.

Design criteria: With regard to scale fidelity, 'sport scale rules OK', so I took a few liberties. Larger tail area (scale size is minute), larger nose moment (easier to fit the tank), slightly increased tip dihedral and cockpit glazing painted on - in essence, real cartoon scale. However, it does look good and recreates the flavour of the full-size aircraft. And that's what really counts!

I used blue foam and brown paper, because it's quicker than a traditional structure and because I had the remnants of a large block of foam to use up, not to mention the reduced costs. Using this method of construction, I can work from sketches rather than proper drawings and can incorporate mods when I finally draw up the design later.

The wing is sparless, with tip panels epoxied to the centre section. Undercarriage loads are taken by a hardwood beam, which also acts as a sub-spar. The brown paper covering, in addition to that of the glass clothed joints, is sufficient to take all flight loads (I haven't had a wing fold yet).

Building notes: The motor boom is made up around a 1/4 in square balsa longeron box section with liteply doublers from the engine bulkhead to aft of the wing seat. The box section is clad with 3/4 in sheet foam; this is carved and sanded to circular section, thinning to oval at the tail end - minimalist stuff, but adequate. The tail feathers, from 1/4 sheet balsa, sit on an elevated balsa tail seat and an aluminium tube with flattened ends supports the tailplane.

The crew pod was carved from a block of blue foam and hollowed out to save a little weight. I didn't bother covering the pod with paper, relying on PVA to seal the surface ready for painting. The lower boom and pod fairings were slotted spanwise to allow fitting and removal of the UC torsion legs, the gaps being filled with foam off-cuts. This allows the aircraft to be flown with or without the UC (if you take the latter option, you will need a helper to do the launch - the offset balance makes her tricky to hold one handed, the second hand being needed to steady the RH wing tip).

For security the fuselage boom is attached to the wing using two dowels at the leading edge and a nylon bolt through the wing at the rear. The pod, not being stressed, locates at the leading edge by one dowel, with a screw plate, aft of the trailing edge, clamping the pod to the wing..."

BV-141 from RCM&E March 1996.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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