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It’s Roddie’s Fault Empty It’s Roddie’s Fault

Post  batjac on Fri May 06, 2016 5:08 pm

I wasn’t going to start anything new until I’d finished off all the other stuff I’ve got sitting around, but Roddie reminded me that I’ve not done anything with the BTC concept in a long while, so I had to get something going.  I like the BTC-4 line the best, which uses the SIG 4” airfoil shaped balsa for the wing.  So my next project will be the BTC-4A.  "A" for Akro.  I grabbed my SIG Akromaster and did a quick measurement of the dimensions, and then scaled them down 62% for the 4” balsa wing stock.

Here’re my initial working drawings:

It’s Roddie’s Fault BTC-4Akro_zpsdgraiave


I’ll have to clear off some room and get this thing thrown together.  One of the principles of the BTC-4 line is that since they’re “Built to Crash”, they build fast and just get a clear coat for fuel proofing, and no time wasted on painting them nice and pretty.  I’ll have to dig around in my wood box and see if I can find wood of different shades to make the surfaces and canopy stand out with just the clear coat.

The Finger Pointing Mark
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Post  batjac on Fri May 06, 2016 5:46 pm

DUH!!!   Rolling Eyes


When I have to draw a straight line greater than 12”, but less than say 18”, I usually draw a line with a 12” metal rule, and then just move the ruler to draw the next leg that I need to get the length I need.  For over 18” I have a longer steel rule.  But, sometimes I don’t get the ruler lined up well with the existing line and the extended line’s a hair crooked, or I make a stupid mistake and the line is longer or shorter than I want.  Anyway,  I was just going through my desk drawer and picked up these two molded plastic rulers to move them out of my way:

It’s Roddie’s Fault Rulers1_zpsdolyd9v4


I don’t normally use the plastic ones for drawing lines, as I think the steel ruler gives me a better edge for the line.  But, I put the two rulers together and started to put them away, when it hit me.  They’re molded.  They have the same shape.  I can nest them together and telescope one over the other.  Voila!  Straight lines and exact measurements over 12”.  How did I not see that before?

It’s Roddie’s Fault Rulers2_zps4uhdvyhu


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Post  NEW222 on Fri May 06, 2016 10:17 pm

Well, allow me to be the first to say "It's about time you figured that out!" Now, I don't have to wait that long to figure it out as you did my homework for me. Very Happy See, I had it all figured out in about one minute from reading your post. Now, all I got to do is go out and find myself a couple of 'nesting rulers'. Glad tomorrow is shopping day. Thank you.
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Post  batjac on Sat May 07, 2016 3:38 am

Okay, I cleaned up the working drawing.  Should be easy enough to build off of now.

It’s Roddie’s Fault 6296f119-7149-4dd1-88e8-fc2e10132ada_zpspcvppu8p


But, looking at it, it's kinda pudgy.  I may take a little off the bottom and the top of the fuselage....

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Post  NEW222 on Sat May 07, 2016 8:29 am

Mmmm. Nice straight lines. Very Happy I actually like it as it is. The thicker fuselage kind of gives it that old warplane look.
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Post  roddie on Sat May 07, 2016 12:15 pm

Hey Mark, I'm glad that I was a catalyst for your designing another airplane. I also like using graph-paper for drawing full-size plans. I bought a pad of 8-1/2" x 11-3/4" sheets and tape two together on the backside, the long way. This provides enough area to draw up to a 23-1/2" span wing.. and usually enough to draw-out the fuse and tailplane either above or below the wing.

It’s Roddie’s Fault 5-7-1610

A set of French-curves and circle-template come in handy for contouring. (I used to use round/oval container-lids and a compass) Drawing a belly-contour, canopy, wing-tips, radii etc. are a lot easier.

It’s Roddie’s Fault Dsc03010
It’s Roddie’s Fault Drafti10
It’s Roddie’s Fault 1-1-1610
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Post  KariFS on Sat May 07, 2016 1:53 pm

NEW222 wrote:Mmmm. Nice straight lines. Very Happy  I actually like it as it is.  The thicker fuselage kind of gives it that old warplane look.

Kinda like P47 Thunderbolt, no?
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Post  batjac on Sat May 07, 2016 4:51 pm

KariFS wrote:
NEW222 wrote:Mmmm. Nice straight lines. Very Happy  I actually like it as it is.  The thicker fuselage kind of gives it that old warplane look.

Kinda like P47 Thunderbolt, no?


*** SIGH ***

Now I have to draw up a BTC-47...

The Easily Suggestable Mark
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Post  RknRusty on Sat May 07, 2016 7:53 pm

Good to see a new BTC in the works, Mark. As for clear, I think Minwax Polyurethane(not Polycrylic unless it's electric) is as inexpensive, easy to apply, and more fuelproof than anything on the market. And it looks great, wiped on with a t-shirt rag. And your fingernails get a lovely yellowish crust around their edges for a couple of weeks. Now that Summer is coming, toes are optional too.
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Post  JPvelo on Sat May 07, 2016 10:21 pm

I recently shot duplicolor clear acrylic enamel on a bare balsa plane, it's holding up to 10% very well.

Jim
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Post  pkrankow on Sat May 07, 2016 10:23 pm

Consult the White Lightening plan on hip pocket. Stretch the nose an inch if you lack true contest balsa.
Phil
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Post  batjac on Sat May 07, 2016 11:26 pm

pkrankow wrote:Consult the White Lightening plan on hip pocket.   Stretch the nose an inch if you lack true contest balsa.
Phil

Already built one.

The Been-There-Done-That Mark
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Post  roddie on Sun May 08, 2016 10:49 am

Hey Mark, do you have any dark-colored Mono-Kote? I realize that you want to go "natural" (clear) with the finish.. and I doubt that you'll get much color-contrast between different balsa sheets. I was thinking that some trim accents cut from the film and applied before the clear might look real good.. and not take much time at all.

These little gliders wouldn't look like much without the graphics. Just doing your canopy and a stripe down both sides of the fuse; nose to tail would stand-out nice in flight.

It’s Roddie’s Fault Natura10

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Post  batjac on Sun May 15, 2016 11:13 pm

Roddie,

I'm sure it would look light years better to do trim, but that would violate my self-imposed rules about a simple as possible build. Maybe after I've flown it a while I'll add some trim.

The Plain Mark
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Post  batjac on Sun May 15, 2016 11:15 pm

Well, after cleaning up a bit yesterday, I was able to start on the BTC-4Akro.  I spent about 2 or 2 ½ hours on it last night.  I’ll try and get a couple of hours this evening to finish it off.

Here’re the plans and wood ready to start:

It’s Roddie’s Fault DSCN4421_zpsoxk272rk


The lines drawn on the 3/16” wood for the fuselage and the engine bearers glued in place.  The engine bearers are ¼” square, so I sanded them down flush with the 3/16” sheet.

It’s Roddie’s Fault DSCN4426_zpsrrbnx1dm


All the wood cut out and rough shaped.

It’s Roddie’s Fault DSCN4428_zpsngcybps5


Aligning the engine in the bearers.

It’s Roddie’s Fault DSCN4433_zpsizff7ds9


The flaps glued to the wing trailing edge and sanded to shape, the tail surfaces glued up, and the canopy and fuselage doublers  glued to the fuselage and sanded.

It’s Roddie’s Fault DSCN4437_zpsktjdkgkq


And trial fitting everything together to see how it all looks.

It’s Roddie’s Fault DSCN4440_zpsikd5im7i
It’s Roddie’s Fault DSCN4441_zpsefdfukmx


Hopefully more tonight.

The Optimistic Mark
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Post  batjac on Thu May 19, 2016 11:34 pm

Well, I got some time to work on the plane again, so I glued up all the wood, installed the bellcrank and bent up the pushrod, and installed the engine.  I balanced the wing at about the 20% point, and then glued in the leadout guide after seeing where it would best be located to get a slight nose down hang.

It’s Roddie’s Fault DSCN4442_zpsvkhyf5yz
It’s Roddie’s Fault DSCN4445_zps42civi9q


I was initially going to use a Medallion .049 and a hard tank, but decided for simplicity to use a balloon tank and a Tee Dee.  I couldn’t find any fishnet like Roddie uses with his bladders, so I just glued two pieces of wood together for a box to hold the balloon in flight.  Again, simple and quick.

It’s Roddie’s Fault DSCN4446_zps4nialixl
It’s Roddie’s Fault DSCN4447_zpsdtxgnhyl


Without the clearcoat, the plane weighs 4.8 ounces, so it should be light enough to perform well on the Tee Dee.  Now I just need to shoot it with the fuel proof coating and it’s ready to test fly.  I figure to start on 35’ lines, and have some 40’ lines at the ready.

The Hung Mark
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Post  roddie on Fri May 20, 2016 4:09 am

batjac wrote:I was initially going to use a Medallion .049 and a hard tank, but decided for simplicity to use a balloon tank and a Tee Dee.  I couldn’t find any fishnet like Roddie uses with his bladders, so I just glued two pieces of wood together for a box to hold the balloon in flight.  Again, simple and quick.

It’s Roddie’s Fault DSCN4447_zpsdtxgnhyl

The Hung Mark

Did you mean "Andras" (Balogh) when speaking of a fishnet (sleeve)? I think he does that with his balloon-tanks.

You might wanna' install a pushrod guide mid-way.. and see if you can straighten the bow in the pushrod near the bellcrank. You may experience some flexing otherwise. Will you be able to easily remove that weight under the stab if it ends up tail-heavy after paint?

It’s Roddie’s Fault Dscn4410
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Post  batjac on Fri May 20, 2016 1:15 pm

roddie wrote:Did you mean "Andras" (Balogh) when speaking of a fishnet (sleeve)? I think he does that with his balloon-tanks.

You might wanna' install a pushrod guide mid-way.. and see if you can straighten the bow in the pushrod near the bellcrank. You may experience some flexing otherwise. Will you be able to easily remove that weight under the stab if it ends up tail-heavy after paint?  

Sorry, Roddie.  I was thinking Rusty.  I believe I saw his Baby Flite Streak with some black fishnet type material holding his bladder tank.  But, I'm probably wrong.  I was up for 36 hours yesterday when I was finishing this up, so my memory was probably kinda fuzzed.

The only pushrod wire I had to hand was thicker than I normally use, so my Z-bend pliers didn't do such a good job on the z-bends.  The little bow near the bellcrank was necessary for free movement of the bellcrank.  The wire is probably thick enough that I don’t need a wire guide, but I’ll use one anyway.  I'll install the safety pin wire guide after clear coating.

I’ve accounted for  the weight of paint in the balancing already.  The plane is still a shade nose heavy.  As soon as the clear is applied, it should be just right.  That’s how I usually do these BTC planes.  If it’s not, I’ll do some tweaking.

But, the more I look at this, I find that little balloon doghouse is quite offensive to my sensibilities.  I’m meeting my wife for dinner later, so I may swing by the Dollar Store or the fabric store and see if they have any kind of fishnet material.

The Goldilocks Mark
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Post  pkrankow on Fri May 20, 2016 1:23 pm

Save some produce bags! Recycle!

Wrap a piece of balsa on a dowel. The curved doghouse will be more aesthetically pleasing.

Phil
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Post  getback on Sat May 21, 2016 9:11 am

pkrankow wrote:Save some produce bags!  Recycle!

Wrap a piece of balsa on a dowel.  The curved doghouse will be more aesthetically pleasing.

Phil
I got some of those saved the Lit Cutes are nice and flexible and good for you too , Mark how does the plane fly she was looking good !! Eric I Love This Forum!
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Post  roddie on Sun May 22, 2016 12:20 pm

Just throwing this out there Mark.. (you know me..) Do you have any of this style cap/hat hanging around?

It’s Roddie’s Fault Balloo10

One mesh-panel would probably be enough to form a balloon sheath/tube and stitch the seam together with thread. As far as attachment to the nose; maybe use a couple dots of epoxy (frt./rear). The mesh-weave imbedded into the glue-dots should be enough to hold securely with the fueled-balloon inside.
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Post  RknRusty on Sun May 22, 2016 1:35 pm

It’s Roddie’s Fault Bladde10

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Post  batjac on Sat Jun 04, 2016 1:40 am

I just weighed the plane in RTF trim.  It's a total of 4.95 ounces.  When I get the TeeDee .051 behaving, I'll try and get some test flying in.  The .051 should fly it a treat.

The Tricky Mark
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Post  fredvon4 on Sun Jun 05, 2016 2:10 pm

Ever since Rusty showed us how he did bladders and the neat side of Fuselage method

I have been finding and saving the various expandable mesh bags some grocery store produce comes in like Tangerines/onions

Yesterday my wife asked me what I was doing  popping all the onions out of the mesh bag and I told her...

She took my hand and walked me out to her Quilting shop and showed me her similar mesh in Yards that she uses over a spool of thread to keep it unraveling

This cheap stuff:
http://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Store_Code=TTE&Category_Code=Thread_Sock

It’s Roddie’s Fault 20160611

Left...black from tangerines
Middel...white fron some onions
Right... white 6" from a yard of her stuff
Far right...Thread Sock keeping it from unraveling
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