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Old Jan 19, 2013, 11:31 AM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
665 Posts
Day 19 -- Motor

OK, I just pulled the trigger on a Turnigy Park 300 and a Turnigy Plush 12 ESC. Both came to $31.11 (USD), which includes S/H. I held off ordering batteries, as I still need a charger, and want to shop a bit more.

This will probably mean I have to revise those former patterns again to match the "X" mount, but that's not a big deal. What's another day's work, right?
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Old Jan 20, 2013, 07:33 PM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
665 Posts
Day 20 -- Fuselage Formers (Again)

I never thought I was going to get this deep into re-engineering the design when I first thought about tackling the Envoy. Adding controls and electric power has required a bit more work to the layout than I anticipated...

The next challenge will be cutting out these formers with my old scroll saw. I just have to remember to "leave the line", use a file to clean out the little notches, and sand away the rest.

All six pieces are attached together internally with lengths of 1/8" spruce. At the front, there is an opening with six notches in three formers (F0, F1, and F2). This forms a snug little cavity for the battery pack once some foam rubber padding is attached. Doing this places the pack as far forward as possible to aid with the CG. Just aft of F2 is a retainer for the pack to push against.

F1 through F4 are cut from 1/16" AC plywood, and will be used for wing attachment points on F2 and F4. Much of their mass is removed, and this allows for the passage of pushrods to the tail surfaces. F0 is cut from 1/8" AC plywood, since the motor's "X" mount will be attached to it. When the motor arrives, I'll check to see if there might also be a need for some doublers behind F0 where the mount screws go.

The longest of the spruce runners provides an attachment ledge for a plywood shelf that the receiver and servos can mount to. I won't know what size openings will be needed for the servos until I get them.
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Old Jan 22, 2013, 04:33 PM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
665 Posts
Day 22 -- Status Report

Still waiting on the arrival of the motor and ESC, should be in by Wednesday or Thursday.

Located the scroll saw blades (finally!). I was shocked to not find them at Home Depot, but happy to spot them at Lowe's. Looked at a couple of tools that I really want (imagine a "Tool Time Tim" grunt here... ), and happy to see they were both Porter-Cable brand. One was a 6" disk/belt sander, and the other a variable-speed scroll saw. Daddy like...

Still have to dig out my 20+ year-old Sears scroll saw, and need to dig out my nearly 30-year-old Delta-knock-off drill press.

The thought has occurred to me to cut F0 out of 1/16" ply, then just use some doublers to thicken up the screw holes and not make the whole former from 1/8" ply. The remainder of the build somewhat hinges on these formers, so until I'm holding them in my hands, I'm temporarily stalled.

I've been lurking through the other build threads, and love the variety of models. It's also given me a couple of "next builds" to think about, once the Envoy is finished.
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Old Jan 22, 2013, 05:00 PM
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One additional tool I've been looking at is a spindle sander. The belt/disc sander is a really nice tool to have, and I use mine a lot, but when sanding to a concave line the disc sander is a good way to mess up (another "ask me how I know this" moment).

Anyway, worth thinking about I believe. I'm of the opinion that as easily as balsa sands, it shouldn't take a high dollar sander to do the job. If anybody has experience with a spindle sander, I'd be interested to know what you think. Will the 1/2 HP 130.00 dollar one do it?
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Old Jan 22, 2013, 05:26 PM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
665 Posts
Quote:
Originally Posted by cd_webb View Post
One additional tool I've been looking at is a spindle sander.
Yeah, I've seen those and know they would work well. But there's an attachment that I use on the drill press which is far less expensive and does (for me, anyway) everything that dedicated tool can do. Check out these Sanding Drums for $30. I bought a set from Sears way back when, and used them quite a bit. Probably need to get a new set...
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Old Jan 23, 2013, 11:45 AM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
665 Posts
Day 23 -- Powerplant

The motor and ESC arrived today. I'm sure it was packed into the smallest box USPS offered, but there was still far more box than content. It felt like they were shipping helium...

Photo 1 shows the combination. As I suspected, I'll need to revise F0 again to fit the "X" mount. Now that I have the motor handy, I can get a more accurate placement of the former at the front of the model.

ADDENDUM: They shipped the wrong "X" mount...
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Old Jan 23, 2013, 12:15 PM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
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Day 23 -- Powerplant

Well, so much for speaking too soon...

The "X" mount does fit, it just fits one way. The hole pattern was slightly wider in one axis than it was in the other, and needless to say, with a 50-50 chance of hitting it, I missed completely. Maybe I should try flying instead. I might succeed...

(Blatant Douglas Adams reference there...)
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Old Jan 23, 2013, 01:04 PM
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South-west France
Joined Sep 2007
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Funny thing about these "X" mounts - most of the ones I have had supplied with motors only fit one way. No problem once you realise this, but it does seem a bit weird - surely it would be easier to produce them completely symmetrical
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Old Jan 25, 2013, 01:57 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
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Craig - don't mean to derail your thread, but I have a question you may be able to answer...

Having seen that you have been working in Inkscape, I downloaded it and after much grunting and swearing and wrestling with concepts I knew nothing about, have managed to trace and adapt a part on the enlarged Dart Kitten plan. It is scaled correctly on the screen (I am using a 1mm grid), but how on earth do I get it to print out exact size? It keeps coming out too small - and the Inkscape instructions are worse than useless for any help for a chap like me who still feels that the loss of the guinea as a unit of currency was where the rot set in.......

PS 'Haven't got a clue, go Google' would be considered an allowable and non-offensive answer.....
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Old Jan 25, 2013, 02:31 AM
KNS
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Switzerland, SO, Olten
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Hi Colonel,
I have realized the same effect when you have someone scan a plan for you and they come back with a pdf -there is often a few percent of loss in size. There was no loss, however, if you have them give you a tiff instead, so this seems to be a file format issue.
My solution is to use a file format other than pdf, and, of course, avoid the "fit to printable area" type of functions (check the diffferent tabs when printing). Print actual size instead.
HTH
-Kai
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Old Jan 25, 2013, 04:57 AM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
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Quote:
Originally Posted by Colonel Blink View Post
Craig - don't mean to derail your thread, but I have a question you may be able to answer...

Having seen that you have been working in Inkscape, I downloaded it and after much grunting and swearing and wrestling with concepts I knew nothing about, have managed to trace and adapt a part on the enlarged Dart Kitten plan. It is scaled correctly on the screen (I am using a 1mm grid), but how on earth do I get it to print out exact size? It keeps coming out too small - and the Inkscape instructions are worse than useless for any help for a chap like me who still feels that the loss of the guinea as a unit of currency was where the rot set in.......

PS 'Haven't got a clue, go Google' would be considered an allowable and non-offensive answer.....
Colonel, welcome to my battle zone with the Gimpscape Dragon!

This is what I was having to deal with. Look in FILE | INKSCAPE PREFERENCES, and click first on the BITMAPS section. Notice the little scroll box marked "Resolution for Create Bitmap Copy". Yours is probably set for 90 DPI. Change that to 100 DPI.

Next, come down to the IMPORT/EXPORT section, and look at the top of that screen for "Default export resolution". Make sure that is also set for 100 DPI.

If you're using a separate bitmap graphics program, like GIMP, make sure it is set to IMPORT images at 100 DPI.

I was having the devil of a time getting images to match until I spotted these settings. You're absolutely right, the documentation is atrocious. Try these changes and see if the output imagery starts to shape up...

ADDENDUM: You might also check to see what the resolution of your PDF scan was. Match the IMPORT/EXPORT value to that when you bring it in to work on in Inkscape.
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Old Jan 25, 2013, 05:37 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
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Thanks Craig - I have simply been using the Inkscape 'Print' command, and stupidly expected that to work.....

I'm away this weekend (snow allowing) but I'll have a look at the settings etc when I get the chance next week.
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Old Jan 25, 2013, 06:17 AM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
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Originally Posted by Colonel Blink View Post
Thanks Craig - I have simply been using the Inkscape 'Print' command, and stupidly expected that to work.....

I'm away this weekend (snow allowing) but I'll have a look at the settings etc when I get the chance next week.
That reminds me of one additional "gotcha" -- check to see if your PRINT command is scaling the image to fit the paper. You might have to "force" the image manually to print at 100%.
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Old Jan 25, 2013, 07:58 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
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Quote:
Originally Posted by cpmcgraw View Post
That reminds me of one additional "gotcha" -- check to see if your PRINT command is scaling the image to fit the paper. You might have to "force" the image manually to print at 100%.
It's OK - I've been looking for that - but some routes to print don't seem to have that option! The other 'gotcha' I encountered was that zooming right out and asking to show the paper outline showed that the drawing was miles away from the paper.....

I know, George, you don't have these problems with a pencil & ruler!!!!
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Old Jan 25, 2013, 04:42 PM
Experienced Balsa Mangler
United States, AL, Tillmans Corner
Joined Oct 2012
665 Posts
Day 25 -- Progress Report

I dug out my old Sears scroll saw today, and managed to get it to run after 15 years of (unkind) storage...

...For all of 10 minutes...

The motor decided I had not paid it enough attention over that 15-year span, and it's now taken to sulking and whining. I think the bearings have either rusted, or whatever lubricant the bearings did have has gummed to the point of not being a lubricant any longer.

Now, I'm trying to decide on whether to just break down and buy a new, cheap, single-speed saw (Harbor Freight for $70), blow for a more flexible, variable-speed saw (Skil for $120, or Rockwell for $130), or try to fix the old one ($???).

Sigh...
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