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General control line discussion => Open Forum => Topic started by: sleepy gomez on June 26, 2010, 09:45:44 PM

Title: I like big biplanes and foam structure
Post by: sleepy gomez on June 26, 2010, 09:45:44 PM
These are photos of SILK.  I use foam, poplar, and no balsa. Covering is silkspan and Rustoleum.   I love biplanes.   Except for the engine, the cost to build SILK was under $20. 
Title: Re: I like big biplanes and foam structure
Post by: sleepy gomez on June 26, 2010, 09:47:20 PM
Maybe my photos are too big for more than one.
Title: Re: I like big biplanes and foam structure
Post by: sleepy gomez on June 26, 2010, 09:49:03 PM
Here is the last of three photos of SILK
Title: Re: I like big biplanes and foam structure
Post by: Gordon Tarbell on June 26, 2010, 11:05:11 PM
What are the specs and power?  I love Bipes also. That is a nice one.
Title: Re: I like big biplanes and foam structure
Post by: Serge_Krauss on June 27, 2010, 08:06:23 AM
Sleepy-

'very interesting plane! So you just covered the foam with silkspan, and the Rustoleum solvent did not attack the foam. With that narrow-ish gap, you also have a pretty reasonable wing loading and neat tips. That's pretty cool...and only $20. Please let us know how it flies.

SK
Title: Re: I like big biplanes and foam structure
Post by: sleepy gomez on June 27, 2010, 10:34:11 AM
For Serge, The covering is silkspan applied with 50/50 Elmer's white glue and water.  It then gets one coat of hot water/unflavored gelatin mix, one packet to 1 1/2 ounce hot water.  This provides a seal where you can pour lacquer thinner on the foam!  I've been doing this since '73.  You mentioned the wing gap.  The RM wings have a 9" average chord.  Measured here at high point to high point the separation  is 5.5". 

For Gordon, click on the photos to enlarge.  All the specs are in captions. 

I hope to fly it next weekend. 
Title: Re: I like big biplanes and foam structure
Post by: TDM on June 27, 2010, 12:00:41 PM
Did you ever see how people build discus launch planes? Take a look at this link and see if you can apply something to your plane.

http://www.rcgroups.com/forums/showthread.php?t=634176&highlight=tabooish

If you need help with the wings I have a CNC hot wire cutter at home.
Title: Re: I like big biplanes and foam structure
Post by: sleepy gomez on June 28, 2010, 08:36:36 PM
Traian, Gee, It must be nice to have a CNC foam cutter.  I have to cut mine using 2 templates.  I don't have a machine.  I simply follow the templates by hand standing over the foam block.  Seldom miss where a light sanding doesn't clean it up.  Course I've been doing this since '73.  I wrote the how to article in Flying Models in '74.  I have even been able to hot wire an elliptical wing with an elliptical planform and elliptical airfoil.  About 20 minutes with a sanding block does the whole wing.  Being on a fixed income, building foam planes allows me to build a lot.  I have 7 all ready to fly hanging in the shop.  I manage to build almost as fast as I crash! 
   Is your CNC hot wire machine store bought or is it a do it yourself type.  I would like to know more.
Sleepy Gomez 863-899-0656   sleepygomez@gmail.com
Title: Re: I like big biplanes and foam structure
Post by: wwwarbird on June 28, 2010, 11:30:21 PM
 Ringmaster wing panels? Huh?
Title: Re: I like big biplanes and foam structure
Post by: sleepy gomez on June 29, 2010, 08:54:25 AM
YUP!  I used Ringmaster wing panels.  They are the foam panels (modified airfoil) from Mike Gibson.  Double tapered, 9" average chord, 42" span with 3/8 x 1/8 spars top and bottom.  I then added foam tips for a total 52" span on both wings.
Title: Re: I like big biplanes and foam structure
Post by: John KruziK on June 29, 2010, 07:24:09 PM
Do you have any building pictures? I really like the idea of a $20 plane. John
Title: Re: I like big biplanes and foam structure
Post by: sleepy gomez on June 29, 2010, 09:34:14 PM
No building photos right now.  On my next build I will photo the whole process and post them.  It is a simple process really.  It does require a hot wire setup (transformer $50) or some other source.  I have a cheap table saw to cut poplar and cedar planks and an old hand elec jig saw mounted under a platform.  The Home Depot is my hobby shop. 
    John, send me your email and I will be sure you see the photos and answer any other questions. 

sleepygomez@gmail.com   863-899-0656
Title: Re: I like big biplanes and foam structure
Post by: john e. holliday on June 30, 2010, 07:13:33 AM
Post the pics on here so the rest of us might learn something.   H^^