HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by z80, who may elect to delete unwanted replies.
Old Jan 23, 2013, 07:29 AM
bbz
Registered User
bbz's Avatar
Australia, QLD, Aroona
Joined Jan 2008
87 Posts
What does the "Chassis CoG" value represent? Is this the COG of the wing with no gear?
bbz is offline Find More Posts by bbz
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 09, 2013, 07:06 PM
Fearless!
mrfx2001's Avatar
Joined Apr 2006
3 Posts
Well I think the nose heavy issue is not balance but the need for something called reflex. A little up in the elevons is required on almost all of the tapered flying wings I have built in the past 40 years. Use the graphic method to find the MAC and do not exceed 20% of the MAC for the first flight . If you do, the aircraft control sticks will be a lot more than TWITCHY. (Mostly uncontrollable) My final balance point is located by pushing the balance point back as I increase expo or mechanically decreasing the control throws or with rates. It's a touchy\feely kind of thing. Washout will help stability. All of your first flights (tuning) should be launched into the wind even if you have to toss it in the direction of the parking lot. Yes, I have hit my own car! No lift from a down wind launch guarantees a botched takeoff. After the third or fourth test flight you should be able to accelerate to full throttle without the wing pointing strait up all by itself. (strait and level flight maintained without elevator correction) If your build has the model approaching 100+ keep in mind that dual rates will be an excellent idea as you will need a lot less throw at high speeds. On some of my deltas I have had less than 3/16s throw max. You will know the balance is correct when you notice the width of the balance zone is about 1/4". (Feels nose heavy to uncontrollable front to back.) The last bit of information I can pass along is if flying electric learn to launch the aircraft with your left hand and fly the aircraft with your right hand thumb on the right stick. I see all to often a person throwing with the right hand and then reaching for the most important control gimbal while the aircraft is burrowing into the ground. Way to much time is wasted. If your thumb is on the right stick you are already flying the wing before it leaves your left hand. OH, did I hear someone in the back with some crack about how do you work the throttle? While holding the TX with your right hand, push the throttle with your chin. Works every time. Build lots of them, you might break a few and all the speed freaks at your field will want one.
Hope I haven't bored you guys with all this. (2/9/2013)
Tomorrow flying my PopWing (TeckOne version) 3300 KV 450 propped 4.75 x 4.75. Awesome. Flies for 4 min on a 3 cell 1300 65c (You can't stand any more than that at full throttle in a tight coarse. (The ground comes up awful fast.)) Fearless
mrfx2001 is offline Find More Posts by mrfx2001
Reply With Quote
Old Feb 25, 2013, 01:41 PM
Registered User
United States, SC, Greer
Joined Nov 2012
68 Posts
If you click on the original wing COG calulator on the first page there is a link to go to the extended version. Does anybody know what the Chassis COG parameter is?

Thanks
SOOFLY is offline Find More Posts by SOOFLY
Reply With Quote
Old Feb 28, 2013, 03:32 AM
Suspended Account
Joined Jan 2013
35 Posts
wow good calculator. Appears that the area computation is showing a value double what it should be. Also appears that the sweep angle to be specified is the sweep of the wing's quarter chord. If I am correct, you might mention that. Thanks for sharing
mark552495 is offline Find More Posts by mark552495
Reply With Quote  (Disabled)
Old Feb 28, 2013, 03:36 AM
bbz
Registered User
bbz's Avatar
Australia, QLD, Aroona
Joined Jan 2008
87 Posts
Quote:
Originally Posted by SOOFLY View Post
If you click on the original wing COG calulator on the first page there is a link to go to the extended version. Does anybody know what the Chassis COG parameter is?

Thanks
its the point at which the wing balances without any gear in it.
bbz is offline Find More Posts by bbz
Reply With Quote
Old Mar 01, 2013, 09:50 PM
Registered User
United States, SC, Greer
Joined Nov 2012
68 Posts
Quote:
Originally Posted by bbz View Post
its the point at which the wing balances without any gear in it.
Thanks for the reply.

One more question.... Is the original calculator at the beginning of this thread in MM's?

I'm assuming it, but I just want to be sure. Thanks
SOOFLY is offline Find More Posts by SOOFLY
Reply With Quote
Old Mar 01, 2013, 09:54 PM
bbz
Registered User
bbz's Avatar
Australia, QLD, Aroona
Joined Jan 2008
87 Posts
Quote:
Originally Posted by SOOFLY View Post
Thanks for the reply.

One more question.... Is the original calculator at the beginning of this thread in MM's?

I'm assuming it, but I just want to be sure. Thanks
It works for whatever units you want to use.
bbz is offline Find More Posts by bbz
Reply With Quote
Old Mar 01, 2013, 10:19 PM
Registered User
United States, SC, Greer
Joined Nov 2012
68 Posts
Quote:
Originally Posted by bbz View Post
It works for whatever units you want to use.
Thanks again for the quick reply. As always, RCG is an invaluable resource.
SOOFLY is offline Find More Posts by SOOFLY
Reply With Quote
Old Mar 02, 2013, 12:17 AM
Registered User
United States, SC, Greer
Joined Nov 2012
68 Posts
I'm not getting the expected results using this calc. Its my first time so I will assume I'm using it incorrectly. Somebody let me know what I'm doing wrong please.

I'm trying to build the following.

Wing Span: 40 inch
Root Chord: 11 inch
Root Tip: 9 inch
Sweep: 11.5 inch

When I apply these measurements I get a wing span of 32 3/4 inch. What am I doing wrong?

Update: Well after reflecting, it seems I should have measured out 20 inches from the root chord to the root tip. I measured 20 inches along the leading edge, which was incorrect. I am cutting one side at a time. Time to get back at it.

Thank you in advance
SOOFLY is offline Find More Posts by SOOFLY
Last edited by SOOFLY; Mar 02, 2013 at 02:04 AM.
Reply With Quote
Old Mar 02, 2013, 02:12 AM
Envies his own avatar
rockyabq's Avatar
Albuquerque, NM
Joined May 2008
594 Posts
Let me try the geometric method and see if that approximately agrees with what you're getting from the calculator...
rockyabq is offline Find More Posts by rockyabq
RCG Plus Member
Old Mar 29, 2013, 07:22 AM
Registered User
Joined Feb 2008
3 Posts
hej all i have a plank i carbon 2800mm i vill youse for f3f soon smile
hobbylars is offline Find More Posts by hobbylars
Reply With Quote
Old Mar 29, 2013, 07:24 AM
Registered User
Joined Feb 2008
3 Posts
i like to her from jour all wat do you thing sent to hobylars1@gmail.com
hobbylars is offline Find More Posts by hobbylars
Reply With Quote
Old Mar 29, 2013, 07:24 AM
Registered User
Joined Feb 2008
3 Posts
hobbylars1@gmail.com
hobbylars is offline Find More Posts by hobbylars
Reply With Quote
Old Apr 02, 2013, 03:26 AM
Registered User
Twawsi2's Avatar
Italy, Veneto
Joined Jun 2004
205 Posts
how do you factor in the use of a blunt section for a wing?
Twawsi2 is offline Find More Posts by Twawsi2
Reply With Quote
Old Apr 02, 2013, 04:20 PM
Envies his own avatar
rockyabq's Avatar
Albuquerque, NM
Joined May 2008
594 Posts
Do you mean a center section that isn't swept?
If so, use this...
http://rcwingcog.a0001.net/
"Fuselage width" will adjust the "span" of your unswept center section.
rockyabq is offline Find More Posts by rockyabq
RCG Plus Member
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
flying wing cg ?'s mscj Foamies (Kits) 1 Mar 03, 2003 10:53 PM
Flying wing CG with shortened span MSB Foamies (Kits) 2 Jul 28, 2002 08:23 PM
Flying Wing CG Choppa Nutta Power Systems 8 Apr 17, 2002 12:45 PM
Flying Wing CG Paul Susbauer Parkflyers 2 Jan 29, 2002 02:31 PM
Flying wing CG Anders Power Systems 4 Oct 05, 2001 05:39 AM