SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old May 05, 2012, 10:28 AM
Wasn't my fault, I had it and
Wacky1's Avatar
United States, WV, Ripley
Joined Jan 2012
147 Posts
Earl, you should change the "prefix" of this thread to a "build thread". I am enjoying this, as I plan one day to enlarge my "new" to me Pica Waco Great deal of learning already here!!!.
Wacky1 is offline Find More Posts by Wacky1
Reply With Quote
Sign up now
to remove ads between posts
Old May 05, 2012, 08:28 PM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
Well now! This is a first!-You have to understand,I'm not an Antique modeler,although I am an Antique, in my own right.
I just "Googled'the Sparky,and found much information.It's the longest running Comet kit,designed in one lunch hour,and kits can still be found today.
The airplane balances at-get this-75% back from the wing leading edge.A high lift stabiliser negated the need for nose weight,in order to limit the full power zoom at launch.
A minor scuffle broke out when I accused someone of improper math during a scaling discussion,saying he enlarged one to 48",by enlarging it 150%.
I wasn't privy to the fact that Sparky began life at 32"....my plans were already enlarged 200%,when I started.
I am going to take liberties with the upper nose design,rounded,rather than angular.Feedback says to also enlarge the rudder and elevator areas.I may add teeny ailerons also..I'm going to make functional wing struts,made with a spar and wing ribs,covered ala a small,high aspect ratio wing...because I want to.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Last edited by epoxyearl; May 06, 2012 at 06:34 AM. Reason: wording.
Reply With Quote
Old May 06, 2012, 10:56 AM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
lots of little pieces.

Just though I'd say hi,while laminating the fin/rudder outlines...7 layers of 1/16" balsa.Soaked over night and spaghetti wrapped around little nails.I LOVE building-I'm having a great time.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Old May 07, 2012, 07:44 PM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
I went to the guys in'Antique and Vintage Airplanes' and asked for help carving propellors.
Within 2 hours,i had a prop blank cut,and one side shaped.I'm making a 16" x 4" pitch prop for the Sparky.I wanted it to be handmade,like the rest of the airplane.

Next,I need to make pitch templates for the second blade to match the first.I washed out the last 1 " of each tip,so the engine thinks it's only turning a 14" diameter prop,instead of the full 16".
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Old May 08, 2012, 08:40 AM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
All the laminating work paid off with a beautiful fin and rudder set..
I've laminated the stabilizer leading edges,and the trailing edge.I'm cutting the stab spar from two pieces of spruce,with shear webbing about half way out ,then sheeting a little bit of the center section.

The stab is 52" in span,but built quite light.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Last edited by epoxyearl; May 08, 2012 at 08:58 AM.
Reply With Quote
Old May 08, 2012, 09:21 AM
Laser Cutter Guy
United States, PA, Greensburg
Joined Oct 2009
247 Posts
Looking good. I am gonna get moving on those wheels for ya in the next day or so. I Gotta get the shop cleaned up a bit first, lol.
RCROBBY is offline Find More Posts by RCROBBY
Reply With Quote
Old May 08, 2012, 11:47 AM
Wasn't my fault, I had it and
Wacky1's Avatar
United States, WV, Ripley
Joined Jan 2012
147 Posts
Very impressed!!!
Wacky1 is offline Find More Posts by Wacky1
Reply With Quote
Old May 08, 2012, 11:48 AM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
Quote:
Originally Posted by RCROBBY View Post
Looking good. I am gonna get moving on those wheels for ya in the next day or so. I Gotta get the shop cleaned up a bit first, lol.
As I said-no big hurry-are they done yet?lol. Actually prefer 5-1/2" if you can.I haven't even started the wing panels yet,so be cool.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Old May 08, 2012, 01:36 PM
Laser Cutter Guy
United States, PA, Greensburg
Joined Oct 2009
247 Posts
Quote:
Originally Posted by epoxyearl View Post
As I said-no big hurry-are they done yet?lol. Actually prefer 5-1/2" if you can.I haven't even started the wing panels yet,so be cool.
5 1/2" it is then.
RCROBBY is offline Find More Posts by RCROBBY
Reply With Quote
Old May 09, 2012, 10:25 PM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
wooden wheels and such

Well,today's Old F---- Breakfast was fun....A discussion concerning the scaling up of Sparky produced many comments,all favorable...

Many were surprised to learn the Balance point was at 75% of the wing chord,toward the tail....But the tail is a lifting wing also,and can carry it's share of the weight.

Someone suggested using a smaller size crankcase for the forward bearing/prop holder,and I may concur.I'll think more about it.At least....

RcRobby is designing a set of wheels,replicating the wood ones from Comet Kits of past years. If the wood is nice enough,we'll just clear coat them with polyurethane.If not,they'll get the blue and cream paint of the airplane.

I'm testing the waters of a one piece 114" wing.The Van will accommodate it,just dont know how practical it'll be.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Old May 10, 2012, 07:42 AM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
Back at the start of this thread,you saw the build of the fin/rudder combination.
I bent 7 -1/16 " strips of wet balsa around a row of nails to hold them while the water used to soften them evaporated. Once they've dried,I disassemble them,and use any white wood glue to glue them securely together.

I've been laminating surface outlines for years....well,this time I didn't put the nails close enough together,and the inner strips formed 'steps' rather than a curve around the nails.

A better way was needed,to make the curve smoother.So following some hint from long ago,we cut a 'pattern',to bend them around..Oh Yeah!

If you ever hear the phrase-'I've forgotten more than he'll ever know' that applied here ....once I remembered that hint,I made a pretty nice bend..
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Last edited by epoxyearl; May 14, 2012 at 06:47 PM. Reason: add pics
Reply With Quote
Old May 14, 2012, 06:51 PM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
The poplar prop worked out,well enough,so I cut a Beechwood blank and have started a "for real" prop construction today.
Progress shots in a couple of days.

Strangely enough,a hand made prop looks like a manufactured one.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Last edited by epoxyearl; May 16, 2012 at 05:05 PM. Reason: Picture added
Reply With Quote
Old May 16, 2012, 07:24 PM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
Old flying buddy wants to go to Seaford tomorrow to get the universal for the test conversion.
Says draggin' my feet won't help...so we're off to see the Seaford Hobbies selection of boat stuff.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Old May 18, 2012, 07:05 PM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,817 Posts
The Sparky prop is finished and working.I'm happy with all facets of it....the total run-out averaged .011,so I dragged it around on a bit of sandpaper on a sheet of glass,to even it out.
Funny-I don't check run out on factory props,but I did on this one..Rather pleased,and surprised that it was so close.
The engine runs very smoothly, and is quiet...Some final sanding and clear finish now,paint when it's ready to go on the airplane.
epoxyearl is offline Find More Posts by epoxyearl
RCG Plus Member
Old May 19, 2012, 08:21 AM
AndyKunz's Avatar
Illinois
Joined Sep 2001
24,049 Posts
You know, I giant rubber-style prop spinning at 300 RPM would have been a neat touch on this.

Andy
AndyKunz is online now Find More Posts by AndyKunz
Site Sponsor
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question upgrading an old thunder tiger sparky 400 to a brushless setup hermanmango Electric Plane Talk 11 Mar 16, 2012 04:41 AM
Discussion How to enlarge scale captainscott Scale Boats 4 Feb 26, 2012 02:08 PM
Discussion Vivell 35 Old sparky engine. Punkie Engines 11 Dec 14, 2011 04:19 AM
Build Log Vintage Sparky electric conversion Jennik Parkflyers 1 Dec 02, 2011 12:44 PM
For Sale REDUCED!!RTF!!!Thunder Tiger Sparky 400 Super Combo Brushless!! Trade? kramer Aircraft - Electric - Airplanes (FS/W) 17 Oct 09, 2011 03:44 PM