Community
Search
Notices
Scratch Building, Aircraft Design, 3D/CAD If you are starting/building a project from scratch or want to discuss design, CAD or even share 3D design images this is the place. Q&A's.

design questions

Thread Tools
 
Search this Thread
 
Old 01-27-2015, 06:00 AM
  #1  
wildwillie3
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: Claysville, PA
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Default design questions

I am designing a Skyvan and I'm trying to make it as close to scale as I can. My question is should I use the real airfoil or should I use one that is more suited for RC?

I can't find what airfoil is used on the real plane.


Thanks in advance

Bill

Attached Thumbnails Click image for larger version

Name:	2516557.jpg
Views:	158
Size:	357.7 KB
ID:	2068220  
Old 01-27-2015, 07:48 AM
  #2  
All Day Dan
My Feedback: (5)
 
All Day Dan's Avatar
 
Join Date: Dec 2002
Location: MANHATTAN BEACH, CA
Posts: 4,606
Received 3 Likes on 3 Posts
Default

You are always better off using an airfoil that has been proven successful for model airplane use than any of the full size airfoils. The two are unrelated. I have used the NACA 2415, 2417 and 2419 over the years for all of my models. Compufoil software is excellent for this. Dan.
Old 01-27-2015, 08:10 AM
  #3  
mmattockx
 
Join Date: Apr 2005
Location: Calgary, AB, CANADA
Posts: 2,428
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by All Day Dan
You are always better off using an airfoil that has been proven successful for model airplane use than any of the full size airfoils. The two are unrelated. I have used the NACA 2415, 2417 and 2419 over the years for all of my models. Compufoil software is excellent for this. Dan.
+1. It may look like the real thing, but flies as a model and the conditions inherent to that. Use an airfoil that suits the flight conditions it will see. I also agree on the NACA 24XX series as an excellent choice for much of our model uses.


Mark
Old 01-27-2015, 08:48 AM
  #4  
perttime
 
perttime's Avatar
 
Join Date: Dec 2005
Location: Tampere, FINLAND
Posts: 1,726
Received 7 Likes on 7 Posts
Default

It seems that the full size Skyvan uses NACA 63A414
http://m-selig.ae.illinois.edu/ads/aircraft.html

What size is the Skyvan model?

Last edited by perttime; 01-27-2015 at 08:56 AM.
Old 01-27-2015, 08:56 AM
  #5  
R8893
My Feedback: (20)
 
Join Date: Oct 2002
Location: Cincinnati, OH,
Posts: 973
Likes: 0
Received 11 Likes on 10 Posts
Default

I like the NACA 23XX airfoils vs the 24XX because the high and low point of the airfoil are both at 30%. Makes for ideal D tube construction.
Chuck
Old 01-27-2015, 09:40 AM
  #6  
wildwillie3
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: Claysville, PA
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Default

@ perttime I have it laid out both at 81" and 90" wing spans.



@ R8893 can you be explain D tube more?
Old 01-27-2015, 04:11 PM
  #7  
R8893
My Feedback: (20)
 
Join Date: Oct 2002
Location: Cincinnati, OH,
Posts: 973
Likes: 0
Received 11 Likes on 10 Posts
Default

wildwillie,
A "D" tube refers to the end view of an airfoil where the leading edge is sheeted back to the top and bottom spar and there are shear webs between the spars. The outline looks like a stretched out capital letter "D". Pretty common design for models. You'll get the most strength out of a spar if it is at the thickest point of the airfoil.
Chuck
Old 01-27-2015, 05:00 PM
  #8  
wildwillie3
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: Claysville, PA
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Default

Oh ok, I know what you mean now.

Thanks
Old 01-28-2015, 06:42 AM
  #9  
wildwillie3
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: Claysville, PA
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Default

Does anyone have a recomendation for power (motor size)? I would like to go with electric.


Bill
Old 01-29-2015, 12:06 PM
  #10  
aeroscale
 
Join Date: Jan 2002
Location: Grant, FL
Posts: 439
Likes: 0
Received 1 Like on 1 Post
Default

It's an easy build and a fun flyer. Two here are electric. 62" span.
Attached Thumbnails Click image for larger version

Name:	DSC_0006w.jpg
Views:	62
Size:	227.2 KB
ID:	2068907   Click image for larger version

Name:	Combo2.jpg
Views:	65
Size:	326.1 KB
ID:	2068908   Click image for larger version

Name:	DSC_0028w.jpg
Views:	72
Size:	317.1 KB
ID:	2068909  
Old 01-29-2015, 12:10 PM
  #11  
aeroscale
 
Join Date: Jan 2002
Location: Grant, FL
Posts: 439
Likes: 0
Received 1 Like on 1 Post
Default

Here's my plan.
Attached Thumbnails Click image for larger version

Name:	PlanONLY.jpg
Views:	107
Size:	2.94 MB
ID:	2068910  
Old 01-30-2015, 04:30 AM
  #12  
wildwillie3
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: Claysville, PA
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Default

Very Cool! Rich
Old 01-31-2015, 12:34 PM
  #13  
BMatthews
 
BMatthews's Avatar
 
Join Date: Oct 2002
Location: Chilliwack, BC, CANADA
Posts: 12,425
Likes: 0
Received 22 Likes on 19 Posts
Default

Originally Posted by wildwillie3
Does anyone have a recomendation for power (motor size)? I would like to go with electric.


Bill
It's hard to say because the motors should be selected for the final model power to weight. And that will need to also be based on if you are intending to carry any payloads and how much the gross weight will be with payload.

You'll find that at 55'ish watts per pound that the model will fly in a scale like manner. At 70 watts per lb it'll fly like a WWII fighter or hot modern private plane. More than 80 watts per lb and you're verging on jet fighter territory. At 100 watts per lb it will be very close to unlimited vertical climbing.
Old 02-02-2015, 04:26 AM
  #14  
wildwillie3
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: Claysville, PA
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the guide lines for power, I guess I will just leave space on the firewalls for larger motors if needed. I do plan on using it for payload.


Bill

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



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.