DH9a - plan thumbnail image

DH9a - completed model photo more pics (2)

by Eric Coates
from Aeromodeller
January 1975 
50in span
Tags: Scale IC F/F Biplane Military Bomber
all formers complete :)
got article :)

This plan was found online 28/02/2012 at: http://www.rcgroups.com/forums/showpost.php?p=20881116&postcount=248
Outerzone planID: oz2503 | Filesize: 498KB | Format: • PDFbitmap | Credit*: algy2


About this Plan

DH9a - Free flight scale power model, for 1-1.5cc diesel. Scale is 1/8 with 33oz flying weight. This is a Nationals winning model. Jan 1975 Aeromodeller.

Quote: - "The model is 'bang-on' scale: tail areas are exact, the dihedral is correct at 3deg, providing ample lateral stability, while wing incidence and section are also exact scale. Although thin, the spruce spars, assisted by working bracing wires, area adequate to carry the loads. The design is the culmination of over twenty years of development of practical working scale structures which look delicate yet are strong enough for years of hard flying. The structure is designed to bend and give in an awkward landing, rather than knock-off. The only part I have reservations about is the undercarriage - I normally fit a torsion-bar type on this class of model, but for the sake of authenticity I fitted a rigid job, allowing the scale bungees to do all the work..."

Update 02/01/2017: added article, thanks to RFJ.

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User comments

A great flier and I added a small Tatone timer under the fuse and by it pulling back a pin (after about 10 to 30 seconds timer) the two balsa bombs on loops held by the pin and staggered so they dropped 1 to 2 seconds apart would drop in FREE FLIGHT mode. I could not get a rise off ground as it only had a MILLS 1.3 cc engine and 9X6 prop or 9X4 I recall, but perhaps a PAW 1.5 cc would have done the trick for R O G. But still from hand launch I won many free flight contests with it. It was a bit heavy as a free flight SCALE model tissue and silk outer cover and little thinned dope with hardwood wing spars by that method of designer Eric Coates, but from a running hand launch at the correct speed pretty fast it would just lift and FLOAT out of my left hand and right hand guiding the stern of the model near the rear sprung suspension with sheering elastic springing as per plan? Never chuck a free flight model, just let them go away at THEIR lift off speed. The profile publications did a colour picture as I recall of a WW1 type for my colouring with a grey rear fuse , I think. Many years as a robust model and so many flights, luckily only short fuel supply in the Mills tank PARTIALLY full so no thermal flyways, but I did have my name and address on it . Today it would easily take small r/c , and i/c but has to always fly minimalist VERY SLOW (again a big prop 9" or 9 1/2' with no rev head flights to stop torque affect and speed crashes!
Lyle - 02/08/2016
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