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Nov 26, 2013, 04:54 PM
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the build continues with completion of the basic fuselage box around which are top and bottom formers and 19 - yes 19 1/8 by 1/4 stringers glued edge on along the length of the fuselage

Before the stringers go on I need to get servo positions and control rods path to tail end sorted out as once stringers are on there will be no room for my 10 thumbs to get inside.

The pics show the build up of the box. I have put in 2 extra lite ply formers around the wing position which made it easier to line up and square the box.

Built upside down as top longerons are level - so once the 2 sides were glued together with the 2 formers, it was laid on the plan view of the plan and pinned in place and all x members glued in place.

Now need to check that the 2 carbon joining rods are correcly aligned in the 3D
to ensure wings mate correctly. Thats the trouble with using rods to join 2 wings thru the fuselage - everything has to be perfectly aligned. talk about making a rod..... ( pun intended )

John
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Nov 28, 2013, 03:41 PM
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First trial to check everything mates up and aligns ok. Rods mated up ok although slight difference in angle of attack which can be addressed with a bit of filing.

96” span plus 4.25 fuselage width totals 100.25” - not my biggest model – the 3 times Mamselle is 108” – but it certainly looks bigger because of the relatively small fuselage.

Photo show the model lightly jammed between floor and ceiling to emphasise the span. Photo of the centre section shows the carbon rods passing thru the fus with the piano wire hooks front and rear of rods which will hold the wing halves together.
The strips of Ό by 1” which run from aft of wing to nose have still to be glued to sides – done after alignment is completed. Wing butts onto these strips instead of the 1/8 by Ό strip longerons which are distributed round the finished fuselage

The keen eyed will note an extra Ό sq spar on one wing – still to put it on other wing – these are at point of highest undercamber and and are intended give more grip to stop covering shrinking away from the undercamber.

john
Nov 28, 2013, 04:06 PM
I like real wooden aeroplanes!
Sundancer's Avatar
That really is coming along well John. Looking very elegant.
Nov 28, 2013, 06:58 PM
Experienced Balsa Mangler
Looking very pretty, John! That thing's massive!
Jan 10, 2014, 04:11 PM
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CP,

yes its big but not as big as my 108" Mamselle - must get a photo of it with the Cumulus for comparison

john
Jan 10, 2014, 04:19 PM
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Slow restart before getting back to balsa bashing at the nose/UC end.

Photos show in no particular order, the balsa wing tube boxes for the carbon rod wing joiners. Helps to stiffen the rods as they pass thru the fuselage. Rods are friction fitted into wing halves and the fuselage to help keep wings tight into fuselage, but I have also fitted 2 sets wing hooks which will ensure the wings don’t try to separate out. Rubber banding can be seen and is easily accessed from the top. No form af attachment of the wings will be seen once hatch is on.

Elevator and rudder servos shown in place to get the 1/8” carbon tubes lined up thru to tail end. As tubes are about 36” long, they need a guide about midway to prevent bowing when pushing. !/8” balsa sheet guide can be seen about ½ way along fuselage – cyano’ed in position once the tubes in place. Photos show the pushrods in place.

john
Jan 10, 2014, 04:55 PM
I like real wooden aeroplanes!
Sundancer's Avatar
Glad to see you are back at the balsa face John.
Jan 31, 2014, 11:35 AM
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Finally got back to the workbench with work on the undercarriage.

One photo shows the soldered up UC cut in two to make it removable and to make covering easier. Also shown is 2 sets brass tubing which will be pushed into built up ply tubes after covering.

The UC wire fits into the smaller diameter brass tube which then fits into the larger diameter tube. This covers me if the thin wire turns out to be too weak for the model, in which case I can pull the inner brass tube out and fit heavier gauge wire. However, I think the thinner wire is going to be ok, as now that its all soldered together, it feels fairly stiff and the only weak point is likely to be the bend on the wheel axle.

The other 2 photos show the ply tube being built round the brass tubing.

Once I have the rest of the front sheeting – 1/8 balsa onto the side framing and then 1/8 lite ply over that – both precurved - I can then start to fit the ½ formers top and bottom followed by the 20 or so Ό x 1/8 stringers.
Mar 02, 2014, 05:41 AM
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olblueyez's Avatar
Been lurking in the Vintage section for awhile now. I have Quaker Flash on the brain.

I've seen too many beautiful planes to mention but I must say, this plane with the racy "Arrow" look does/will look simply amazing.

God I hope its red.
Apr 20, 2014, 04:01 AM
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Back again after another layoff – too easily distracted

Finished the stringering – 20 off 1/8 x Ό balsa strips – biggest problem was keeping them straight round the compound curves – slots easy to cut thanks to Permagrits 1/8 slotting “file”

Thought I would put the model together to see how it looks – 48” fuselage is tiny by comparison to wings which makes the model look even bigger

Few pics to show various points.

The removable U/C track is small compared to the span – it will be interesting to see how it behaves on takeoff and landing on crosswind.

One pic shows the Ό” carbon rod wing joiners and the hooks for rubber banding the wings together. The rods go through 2 layers of 1” x Ό” side runners and then thru 2 “tubes” built up from balsa. These can be seen in some of the pics

Whole of front top deck is removable hatch – so no excuses on accessing everything behind the motor bulkhead. Held on by 2 locating dowels at front and magnets at back.

Motor bay and cowling still to be done but will do the tail end first as a break from the fuselage

John
Apr 25, 2014, 07:08 AM
KNS
KNS
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beautiful, just beautiful!
Looks like a relatively short post-CG fuselage for this design. But maybe it only looks like that given the angle the picture was taken?
May 04, 2014, 12:56 PM
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Tailplane and fin construction more or less complete with sanding still to do to tidy up.

Both featured tapering symmetrical sections – meaning either variable packing to build on plan -or, as I did – trimmed one side off the all the ribs and built flat on plan.
You can just about make out the trimmed sections cyanoed back onto the fin.

The tailplane however – I might leave flat – as this will give a thin lifting section which will help to reduce zooming when varying flying speeds between gliding and climbing. The tailplane has zero incidence

Rudder and elevators were built rear of the main spars shown on the plan – the natural point to do this from. I don’t think the large rudder will produce any problems but the resulting elevator is huge – so I trimmed ½ “ off its width. Both need to be fairly big as the short fuselage produces a short moment arm for the control surfaces to work on.

Elevator sections joined by a short length of 1/8” carbon fibre tube cyanoed into grooves – very light and very strong.

The spars and rudder and elevator leading edge strips are all 3/8” sq balsa – much too big – but again tying in with the plan x-sections.

The rudder will sit between the additional ribs on the tailplane – tight fit at moment and will be even tighter when covered. But will also be held in with a woodscrew coming up through the bottom of the t’plane into the sheeted section of fin base.

Photos illustrate most of points above

Just leaves the nose and motor mounting to do before a final sanding and then covering

John
May 29, 2014, 05:15 AM
I like real wooden aeroplanes!
Sundancer's Avatar
Has it stalled John? Or is the flying season to blame!
May 29, 2014, 10:18 AM
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Quote:
Originally Posted by Sundancer
Has it stalled John? Or is the flying season to blame!
yes and no - I get a bit done now and then - mostly then

what flying season ? - weather has been abysmal - but unbelievably sam1066 event at middle wallop looks good for this weekend and I hope to start training my 6 yr old grandson in the noble art of fetchermiting.

Only odd bits to do to complete construction on the cumulus and then onto covering - more decisions

john
Jul 01, 2014, 03:36 PM
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With exception of a few bits and bobs, construction of the Cumulus is finished.

Weight with all the gear in is 4 lbs 4 ozs (incl 3S 3000 lipo ) so I am hoping to come in at 5 lbs completed. This is for the 96" span model.

CG uncovered without the lipo is at 33% - so not expecting any CG problems as lipo can be placed anywhere from 5" behind to 8" in front of CG courtesy of the very long removable top deck.

Photos below show the disassembled bits then the assembled. Motor mounted on a removable slide in 1/4" lite ply plate.

Thought the frame against the green grass would show up nicely.

Now all I have to do is decide what to cover it with and the colours

I was tempted to cover with doped tissue over mylar as all sections of the frame are very stiff and dont need a strong covering to strenghten it up. That would be about the lightest weight and would be under the 5 lbs but the doped tissue does not adhere to the mylar which results in hanger tears.

Colours are still between translucent red with white trim or translucent blue with white trim but not sure on visibility of the blue when thermalling up high - Any comments re this Allen ??

john

john


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