Greyhead

This is one of my all time favourite aeroplanes, and model. I built it back in 1997/8 before I went digital so unfortunately no construction photos, just a quick talk through some of the “interesting” building methods used.

It took several trips to use the school photocopier to enlarge the 1/72 nd scale 3 view to the 54" span I’d decided would be suitable for the Laser 70. The problem with using a photocopier is the thickness of the outline increases so a new “plan” with thin lines has to be traced after only a modest enlargement and the process repeated but I hope you’ll agree the end result is most pleasing.



The fuselage is a simple girder box using 1/4" square spruce longerons with balsa cross braces. 5 sets of formers were fitted, nose, wheel attachment points, front of fin/tail plane and fuselage rear, to give the correct circular section with polystyrene blocks glued in-between. The fuselage was then shaped using rough sandpaper, this must be the messiest modelling job I’ve ever done; the polystyrene “dust” sticks to everything (static electricity?)! Individual panels of Obechi veneer were then attached with “wing skinning” adhesive.

The wing construction was rather unusual but works well, in fact an SE5a I previously built using this method is now on it’s 4th owner and still flying regularly. The top main spar is 1/2" x1/8" balsa with 1/8" square spruce glued top and bottom and faced on one side with 1/64" ply, the lower wing has a thinner section so used smaller balsa. Polystyrene aerofoil sections, cut with a hot wire bow, are glued in front and behind the spar then balsa leading and trailing edges added. Then “false” ribs from 1/16" square balsa glued in place and excess polystyrene from spar to LE and spar to TE removed, again using the hot wire bow, to allow the covering to sag

The spinner is made from fibreglass and the entire Litho plate covered cowl is removable for easy access to the radio gear and engine.

Next post will be about flying the model and this is where the title will be explained!

wonwinglo

*** She is a beauty Grahame,your fuselage construction is perfectly practical for this type of full size structure,the originals were built by top class furniture craftsmen,a practise repeated with the Mosquito in WW.2.
A very sleek biplane for its day and your model certainly captures the graceful lines.
Regarding your wing construction I used a similar method on a DH.71 monoplane,once covered you would never know there was no conventional structure underneath,the torsional strength is superior to the normal thin section built up wings.

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'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

Greyhead

Barry

I believe the method of wing construction using a full depth laminated spar and foam was originally developed for high aspect ratio, thin aerofoil section gliders, the original foam / veneer wings just weren’t up to the job. I adapted their method by missing off the veneer, adding “false” ribs and covering with Solatex, as you say indistinguishable from the “real thing” and certainly a lot quicker to build. All this was of course when carbon fibre was still prohibitively priced.

Unfortunately it wasn’t a viable construction method for the Elf with folding wings and associated locks etc.

Grahame

Greyhead

When reading articles in the modelling press about own designs they always seem to say something along the lines of “a couple of clicks of right trim and she was flying hands off”. Well this has never happened to me! Usually it takes at least 4 or 5 flights to get the trim sorted out.

You can imagine my delight when the Albatros took off and "with a couple of clicks of right trim" flew near enough dead straight with a steady climb out. At a safe height, a gentle left hand turn, not too much bank and head downwind gaining speed as we go. My heart rate had slowed already; this is too easy, so another gentle left turn to come into wind. PANIC, the turn keeps tightening and she dives into the ground.

Thinking about it now this was not dissimilar to the recent demise of the Gordon Nichols B52!

It’s a testimony to the strength of the construction methods used that the damage was relatively light. A crack in the spinner, a bent undercarriage leg and both left hand wings had damaged leading edges.

After repairs subsequent flights proved that it was no fluke, the model still refused to come out of some turns but I was ready for it now so managed some semblance of control. By cutting the power immediately I suspected a problem I managed to get down in one piece.

I, and everyone I asked, was stumped but my brother explained the problem on one of the modelling forums and got a possible reason (useful things these forums!!). More intense research, hence the title of this thread, showed that the early full size DVa suffered from the same problem and actually killed several pilots before a modification solved it.

The model in this configuration flies great, can you “spot the difference” and so work out what was going wrong?



I’ll leave it a there for now and if no one works it out the next post will have the answer and another “interesting” flying episode.

wonwinglo

My guess is that the wings were flexing in flight causing a trim change,I have had experience of this myself with a model of the Flying Flea,it is a bit difficult to see from the last photograph but have you modified the lower 'V' strut arrangement ?

__________________
'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

No.6

wow! she's a cracker Greyhead.

I have started to build an Albatros DVa. ARTF parkflyer. Not a patch on your model of course!

I would like one day to build (and fly!) a DR1 or an Eindecker

Being a beginner, its good to see things that we can aspire to.

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duncan

Looks like you`ve added a couple of small struts at bottom of of main struts( going to L.E.) to stop it(L.E.) "tucking under"?

Greyhead

Give that man a coconut! Oops, get another coconut!!

You’re both right, when the Albatros Company made the lower wings narrower to improve visibility and changed to V interplane struts on the D111 they encountered wing twist problems. For some unknown reason they “transplanted” this wing configuration, without alteration, onto the DV.

Belatedly they added the small struts to the LE and stiffened the construction to eliminate the twist. This site shows the development from D1 to DVa.

http://www.theaerodrome.com/aircraft...batros_di.html

The other “interesting flying episode” happened a couple of seasons ago and clearly shows at least one advantage of flying biplanes.

Perhaps the series of “less than perfect” arrivals early on in the life of the model had weakened the wing structure or maybe I just hadn’t built them strong enough in the first place but on this occasion the spars of both top and bottom left hand wings failed. The model descended quite rapidly with a crazy amount of dihedral but the rigging held everything together and I managed to land with minimal extra damage, just some to the undercarriage. If it hadn’t have been an “old stringbag” it would have resulted in a terminal dive to terra firma!

A fuzzy picture but it goes to prove that she flew again!



Keep up the good work No.6 you can only get better and remember we all started as beginners!!

Grahame