Go Back  RCU Forums > RC Airplanes > RC Jets
Reload this Page >

1/4.5 T-38C Talon scratch build

Notices
RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

1/4.5 T-38C Talon scratch build

Old 03-25-2020, 07:47 AM
  #76  
ravill
My Feedback: (11)
 
ravill's Avatar
 
Join Date: Jan 2003
Location: Granite Bay, Ca
Posts: 5,110
Received 5 Likes on 5 Posts
Default

Thomas and Paul for president!

The work you guys are doing, and sharing, is simply amazing and inspiring.

To see this fly will be amazing!
Old 03-25-2020, 08:49 AM
  #77  
invertmast
Thread Starter
My Feedback: (22)
 
invertmast's Avatar
 
Join Date: Dec 2003
Location: North Port, Fl
Posts: 7,808
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by ravill View Post
Thomas and Paul for president!

The work you guys are doing, and sharing, is simply amazing and inspiring.

To see this fly will be amazing!

im just avoiding sanding that fuselage! LoL
Old 03-25-2020, 01:21 PM
  #78  
invertmast
Thread Starter
My Feedback: (22)
 
invertmast's Avatar
 
Join Date: Dec 2003
Location: North Port, Fl
Posts: 7,808
Likes: 0
Received 2 Likes on 2 Posts
Default

First halves of the T38 horizontal stabs and rudder molds are done:

abrasion resistant surface resin in place





First 4 glass layers in place and epoxy tooling dough to beef up the edges of the rudder mold and thicken up the horizontal stab molds to provide some additional rigidity.







last 4 layers of fiberglass down. This half of these molds are now down.



Old 03-25-2020, 06:42 PM
  #79  
JSF-TC
My Feedback: (2)
 
JSF-TC's Avatar
 
Join Date: May 2002
Location: Fort Worth, TX
Posts: 988
Likes: 0
Received 1 Like on 1 Post
Default

Thomas,

Great work on the molds. Your parting planes and process looks familiar

Questions

What are you using for your alignment dots?

How do you like the tooling putty? I've been making up a thick epoxy mixture with thixotropic silica to support the sharp corners of the mold surface coat before I start laying up the glass. Does putting some glass down first then using the putty work better, and force the glass into the corners?.

I seem to have settled on using 6 layers of 9oz satin twill weave for my molds - it works out to be a 2-3mm thickness and seems plenty stiff once cured.



Rav,

Thanks for the vote of confidence, but I'll stick to model building. I'm the most apolitical person you've ever met. Wouldn't touch that job with a barge pole!

Glad you are enjoying my stumbles through self-taught scratch building. I'm also working on a Spitfire using similar methods that is turning out reasonably well.



Paul
Old 03-25-2020, 07:40 PM
  #80  
invertmast
Thread Starter
My Feedback: (22)
 
invertmast's Avatar
 
Join Date: Dec 2003
Location: North Port, Fl
Posts: 7,808
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by JSF-TC View Post
Thomas,

Great work on the molds. Your parting planes and process looks familiar

Questions

What are you using for your alignment dots?

How do you like the tooling putty? I've been making up a thick epoxy mixture with thixotropic silica to support the sharp corners of the mold surface coat before I start laying up the glass. Does putting some glass down first then using the putty work better, and force the glass into the corners?.

I seem to have settled on using 6 layers of 9oz satin twill weave for my molds - it works out to be a 2-3mm thickness and seems plenty stiff once cured.



Rav,

Thanks for the vote of confidence, but I'll stick to model building. I'm the most apolitical person you've ever met. Wouldn't touch that job with a barge pole!

Glad you are enjoying my stumbles through self-taught scratch building. I'm also working on a Spitfire using similar methods that is turning out reasonably well.



Paul

Paul,
the laser cut parting planes are a life saver!

im using rubber furniture bumpers for the alignment dots. The ones on these are about 3/8” diameter 1/2round style.


as for the putty/dough, the stuff is awesome. I have used it on numerous other projects and if works great for doing small molds like gear doors, hatches, etc.

i put 1-2” wide strips of glass on the parting plane surface with the edge butted up into the corners by the parts. I then mixed up chopped CF strands and epoxy into a moderately dry mixture and put that into the corners to act as a fillet. Then 2oz glass went over it all and i pressed firmly into the CF filled area’s to help remove any air bubbles from the mixture.

i put the tooling putty/dough between the layers of 22oz to help add some additional rigidity to the entire layup.

From trimming the excess, it looks like just the glass area’s is about 2-3mm thick. In total it took about 3 1/2 hours to do these mold halves.
Old 03-25-2020, 09:21 PM
  #81  
jetspud
 
jetspud's Avatar
 
Join Date: Dec 2001
Location: shreveport , LA
Posts: 1,112
Received 0 Likes on 0 Posts
Default

Were is the buy now button 😁

David
Old 03-26-2020, 04:52 AM
  #82  
JSF-TC
My Feedback: (2)
 
JSF-TC's Avatar
 
Join Date: May 2002
Location: Fort Worth, TX
Posts: 988
Likes: 0
Received 1 Like on 1 Post
Default

Thomas,

Thanks.


i put 1-2” wide strips of glass on the parting plane surface with the edge butted up into the corners by the parts. I then mixed up chopped CF strands and epoxy into a moderately dry mixture and put that into the corners to act as a fillet.
That is a great idea, and that provides more direct reinforcement to the surface coat that an initial fillet of thickened epoxy. I'll try that on my next one.


My laser crapped out the other day, after nearly 2.5 years of use. Not bad I guess for a cheap laser, but currently over 1month delivery of a new tube. Back to CAD work in the mean time.


Paul
Old 03-26-2020, 06:01 AM
  #83  
invertmast
Thread Starter
My Feedback: (22)
 
invertmast's Avatar
 
Join Date: Dec 2003
Location: North Port, Fl
Posts: 7,808
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by JSF-TC View Post
Thomas,

Thanks.




That is a great idea, and that provides more direct reinforcement to the surface coat that an initial fillet of thickened epoxy. I'll try that on my next one.


My laser crapped out the other day, after nearly 2.5 years of use. Not bad I guess for a cheap laser, but currently over 1month delivery of a new tube. Back to CAD work in the mean time.


Paul

yea i have tried various things over the year to prevent the molds from chipping in corners, nothing seems 100% full proof, you almost have to put the glass cloth into the corner while the surface coat is right before the point where you can leave a fingerprint, but not transfer the surface coat to you finger. That way the glass kind of “sinks” into the surface coat.

if there’s anything i can cut for you, let me know....


thomas
Old 03-26-2020, 06:01 AM
  #84  
invertmast
Thread Starter
My Feedback: (22)
 
invertmast's Avatar
 
Join Date: Dec 2003
Location: North Port, Fl
Posts: 7,808
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by jetspud View Post
Were is the buy now button 😁

David

couple months away. Lol
Old 03-26-2020, 04:12 PM
  #85  
invertmast
Thread Starter
My Feedback: (22)
 
invertmast's Avatar
 
Join Date: Dec 2003
Location: North Port, Fl
Posts: 7,808
Likes: 0
Received 2 Likes on 2 Posts
Default

Trimmed up the mold edges and removed the parting planes. I’ll wax and pva these and then the second halves will be ready to lay up.






Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.