Avia BH-3 (oz10535)
About this Plan
Avia BH-3. Free flight scale model monoplane fighter.
Quote: "Free flight scale model for 0.5 - 1.0 cc IC power, or geared Speed 400 electric motor. Avia BH-3, by Andrew Hewitt.
Czech this out! This 1920s low wing monoplane was ahead of its time. The Avia BH-3 makes a great subject for FF or micro RC.
Built in December of 1921 in Czechoslovakia, the Avia BH-3 represented probably the most advanced single seat fighter of its time, possessing the classic monoplane form, which was to rule the roost 20 years later. In many ways it was too advanced - monoplane aerodynamics were in their infancy; this high speed, fast-climbing fighter proved too tricky to fly for the average pilot. Despite being built in small numbers, some survived remained in training units up until 1929. Some of the full-sized flying characteristics were not too good however, it spun out of turns, was unstable in a dive and once inverted, preferred to remain there!
However, the Avia is an attractive scale subject with good proportions, except for the rudder area - but the deep rear fuselage makes up for this shortfall. The construction is straightforward and only requires care and accuracy, not years of experience. The prototype model has been flying and crashing for 15 years and will not die, despite my efforts! Any 0.5 cc to 0.8 cc diesel engine will suit this model, using a 7x4 or 8x4 propeller. The prototype has gobbled up two DC Merlin engines and is currently on its third. Only two-thirds power is required for sedate flight.
Although designed as a free flight model, with the micro R/C equipment available now, it should be quite an easy job to fit 3-channel gear and power it with either IC or electric Speed 400.
Construction. Study the plans till you know them inside out, as a good deal of information has been placed on there for your benefit, not for show. Take your time and build carefully, do not allow any stress to be built in - do not force joints, but trim each to suit, this will minimise warps.
Wings, The wings are simple, all that is different is the strange taper. Note that the deepest rib section is at R5, the strut rib position. The section then tapers away towards the root and tip from there. Cut out all the ribs and number them, to save confusion later. Note that the leading edge is cut from 3/16 sheet and that the aileron spars are cut from 1/8 sheet. Choose firm, 1/8 square balsa wing spars and hard balsa for the trailing edge. Pin down the leading and trailing edges, the aileron spars and the two bottom wing spars..."
Avia BH3, Model Flyer, January 2002.
Direct submission to Outerzone.
Supplementary file notes
Article pages, thanks to RFJ.
Did we get something wrong with these details about this plan (especially the datafile)?
That happens sometimes. You can help us fix it.
Add a correction
Do you have a photo you'd like to submit for this page? Then email firstname.lastname@example.org
User commentsNo comments yet for this plan. Got something to say about this one?
Add a comment
* Credit field
The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.
This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.
© Outerzone, 2011-2019.
All content is free to download for personal use.
For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.
Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.