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        Discussion FROG Build off - 2012 Raven x2

#1 sparks59 Jan 07, 2012 10:51 PM

FROG Build off - 2012 Raven x2
 
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I finally cleared away the Christmas decorations and made some space on the dining table to set out my building board.

The object of the exercise is to get started on the Raven. I had already upscaled the plan to 200% but hadn't really studied it much, other than to see it's a relatively simple build, even the conversion from rubber power to RC electric should be ok.

The stock plan primarily uses 1/16th balsa for the build. I know that many would use 1/8 when building at 200%, but I think that will be over the top and finish up too heavy for my liking.

So, I had a look in the balsa box and found I had a couple of sheets of medium 3/32 that were going spare. Decision made. As I was down sizing the thicness, I left out the 'holes' from the fuse sides, cutting only the slots to accept the formers.

#2 sparks59 Jan 07, 2012 11:00 PM

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Then, onto cutting formers and ribs etc.and getting the fuse sides together using my 'special' fuselage rigging jig....

I hadn't thought about the use of thinner material whilst cutting out the formers, with the obvious result that the tabs protruded a little too far externally. Nothing a razor blade and sandpaper won't sort out when its all dry though.

sparks

#3 sparks59 Jan 07, 2012 11:28 PM

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Made a little more progress yesterday, after spending the morning at the flying site in wonderful cool, flat calm conditions. The repaired Popsie still flies just as well as it ever did, so I must have got it about straight, does need a little more downthrust though!

Anyway, cut out the remaining ribs, also from 3/32nd balsa. Determined the position and designed a motor mount former. I'm not entirely sure yet, but will probably be using a HXT Blue wonder motor. I have a selection of these in various kv guises and they are all the same size and mounting, with only minor differences in capacity.

So long as it doesn't finish up too heavy, (it should be less than 1lb), I think the motor will have enough wallop. If not, the mounting is far enough back to enable a slightly more powerful lump to be fitted.

Also fitted the UC, using a proprietary one that was found in the bits drawer. A little shorter than the plan, but then again it doesnt have to accomodate a big rubber powered 'punka' prop. With wheels, it should take a 7 or 8 incher with ease.

That's all for now

sparks

#4 Sundancer Jan 08, 2012 01:44 AM

Hello Sparks, glad to see you back at the board. Good progress, told you it would be a quicky!

#5 owlsabie Jan 08, 2012 03:16 AM

Hey Sparks ! Great to hear that Popsie is alive and well again. Wow - fast progress on this one:popcorn:

Owl

#6 sparks59 Jan 08, 2012 04:25 AM

Thanks for your words of encouragement guys.
I was really pleased to get the old Pops repaired and over the moon that it has only gained about a half ounce in weight, and still flies really well. I couldn't get on with anything until I had done the repairs!

Owl is right, progress has been rapid, but I have only been at it for a couple of evenings. There isn't really a lot to do, and the shapes are mostly square / angular which can be cut quickly.

Thinking of making built up tail surfaces rather than sheeted as the original plan. I would not normally think twice about changing a design, but would welcome any comments on this aspect.
sparks

#7 RFJ Jan 08, 2012 04:29 AM

Quote:

wonderful cool, flat calm conditions
Lucky so and so :D Not had one decent flying day here since Christmas - too windy - so the Gladiator is yet to fly.

Will be following the Raven build with interest - you may be a candidate for a Billy Whizz merit award. Good progress so far and I like your eatable fuselage jig :eek:

As for the tail surfaces - if you have a suitable bit of wood then use it. If not, build them up.

Ray

#8 Yak 52 Jan 08, 2012 04:39 AM

Looking good Sparks, watching with interest...

Jon

#9 Sundancer Jan 08, 2012 06:29 AM

I'd personally go for built-up fin and tailplane (3/16" thick, criss-cross 3/32 square internals) and solid rudder and elevators, but that's just me - never use one piece where 20 will do! I'm sure solid sheet (? 1/8") would be fine if it is decent quality, but I would include opposite grain anti-warp keys.

#10 sparks59 Jan 08, 2012 07:06 AM

Thanks guys.
I don't think i'm in for a BW award just yet Ray... but here's hoping for a special mention eh ;)


I think I will go for the built up jobby. Might do a criss cross even, have to see what material I have. I know that I have some 3/16 sq as that's what I was thinking i'd use. Think i'll probably build the fin as well.

sparks

#11 marksherlock Jan 08, 2012 07:57 AM

Hi Sparks,
The Ravens looking good:)
Thats the same size as my Linnet.
I went with a built up tailplane in the end(not least because it looks nicer) and 3/32 sheet fins. I think the Raven wing was very similar to the Linnet.
I get the impression when I fly mine that even if it were built heavier with more wood, it would still be a great flyer:)
Keep up the good work!
Mark

#12 sparks59 Jan 10, 2012 12:16 AM

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Thanks for your words of encouragement Mark.

Progress update.
A little bit of progress on the Raven last night, set out the plan of the horizontal stab and had a rifle through the wood box to see what could be utilised. I didn't have sufficient 1/8th to make it solid, but had already decided to build it from sticks.
I did think about using George's most elegant methods of lamination and criss cross construction, but in the end I need this build to be simple and fairly quick, so I just roughed out the angles in pencil on the plan and started cutting and gluing!

I'll prob make the elevators from sheet and then set about the fin!

sparks

#13 sparks59 Jan 10, 2012 01:10 AM

Reminder to self. Need to put in a pair of guides to allow the fin to slot in, to keep it square, straight and well supported.

#14 Sundancer Jan 10, 2012 03:34 AM

Just beat me to it Sparks, I was about to say "don't forget the fin mounting"! Nothing worse than getting to some advanced stage and finding you have missed out a bit of vital structure - don't ask how I know:D

Glad to see good progress

#15 czirh Jan 10, 2012 03:35 AM

Hello Sparks,
looking good. :)

Cem


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