HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by skunkworks2006, who may elect to delete unwanted replies.
Old Feb 26, 2013, 08:03 PM
radian 4700
francoishaha's Avatar
Canada, QC, Saint-Hyacinthe
Joined May 2011
167 Posts
Still under construction, maiden planned for this week end.
I set the CG 1/2" behind the leading edge of the wing for the maiden... i hope this will be right. I need to make some air intake for the motor and it's ready to go!


francoishaha is offline Find More Posts by francoishaha
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 26, 2013, 08:48 PM
What goes up, must come down
crazy1pilot's Avatar
United States, MI, Midland
Joined Sep 2009
698 Posts
Should add a canard!I hope it flys as good as it looks

Crazy1
crazy1pilot is offline Find More Posts by crazy1pilot
Reply With Quote
Old Feb 26, 2013, 09:12 PM
AP-stick
ggtronic's Avatar
Montreal
Joined Nov 2005
1,587 Posts
Quote:
Originally Posted by francoishaha View Post
Still under construction, maiden planned for this week end.
I set the CG 1/2" behind the leading edge of the wing for the maiden... i hope this will be right. I need to make some air intake for the motor and it's ready to go!
video
ggtronic is offline Find More Posts by ggtronic
Reply With Quote
Old Feb 26, 2013, 10:59 PM
Crashaffinity on youtube
CrashAffinity's Avatar
Joined Nov 2012
2,920 Posts
Quote:
Originally Posted by francoishaha View Post
Still under construction, maiden planned for this week end.
I set the CG 1/2" behind the leading edge of the wing for the maiden... i hope this will be right. I need to make some air intake for the motor and it's ready to go!
damn that is a purdy plane!
CrashAffinity is offline Find More Posts by CrashAffinity
RCG Plus Member
Old Feb 26, 2013, 11:37 PM
cheapskate extroardinairé
United States, CA, Marin
Joined Jul 2011
1,040 Posts
oooooh, seeeeeexy! looks like it will be nose heavy tho, maybe some canards are in order? either that or chop the nose down a bit. 1/2" seems pretty nose heavy to me.
baconflyer is offline Find More Posts by baconflyer
Reply With Quote
Old Feb 27, 2013, 07:38 AM
radian 4700
francoishaha's Avatar
Canada, QC, Saint-Hyacinthe
Joined May 2011
167 Posts
I made a .25 scale of the plane and made gliding test. Yes my plane is nose heavy, but experience tell me that i prefere a nose heavy trimmed up rather than a tail heavy for the maiden. And i go with the flow, i will put a canard.
francoishaha is offline Find More Posts by francoishaha
Reply With Quote
Old Feb 27, 2013, 08:12 AM
Registered User
Joined Jan 2005
413 Posts
The CG is not 'dependent' on the nose length. The CG depends on the wing design. I've never heard of a main wing with a CG of less than ~25% - 33%. At 1/2" from leading edge CG I think you'll need an elevator the size of mount Everest!
TigerPilot is offline Find More Posts by TigerPilot
Reply With Quote
Old Feb 27, 2013, 09:03 AM
radian 4700
francoishaha's Avatar
Canada, QC, Saint-Hyacinthe
Joined May 2011
167 Posts
Quote:
Originally Posted by TigerPilot View Post
The CG is not 'dependent' on the nose length. The CG depends on the wing design. I've never heard of a main wing with a CG of less than ~25% - 33%. At 1/2" from leading edge CG I think you'll need an elevator the size of mount Everest!
I check the funjet cg and it look realy close to the leading edge...
francoishaha is offline Find More Posts by francoishaha
Reply With Quote
Old Feb 27, 2013, 11:10 AM
2^p - 1
signflyer's Avatar
United States, MO, Springfield
Joined Feb 2003
1,326 Posts
Unless your wing is rectangular, it's incomplete to describe 'cg at 25%' or worse 'CG at 2in from LE'.
CG should be described at a percentage of MAC. For typical planes, 25% of MAC is a good estimate. For deltas, flying wings and others, it may not be.
signflyer is offline Find More Posts by signflyer
Reply With Quote
Old Feb 27, 2013, 11:21 AM
cheapskate extroardinairé
United States, CA, Marin
Joined Jul 2011
1,040 Posts
can you give us the dimensions of the wing? then we can help you with the cg. it looks to me like you have about an 8" chord, which means 1" from the leading edge would be a 12.5% cg, meaning you will be using constant up elevator. this will increase drag (reducing both top speed and efficiency) and also you will have to land very, very fast so as not to run out of elevator for the flare. I would recommend 2" back as a good starting place, then move it rearwards from there until it is a little too tail heavy for your liking, then move it forward a little bit. at this point, it should fly level at neutral elevator. good luck!
baconflyer is offline Find More Posts by baconflyer
Reply With Quote
Old Feb 27, 2013, 11:36 AM
radian 4700
francoishaha's Avatar
Canada, QC, Saint-Hyacinthe
Joined May 2011
167 Posts
Quote:
Originally Posted by baconflyer View Post
can you give us the dimensions of the wing? then we can help you with the cg. it looks to me like you have about an 8" chord, which means 1" from the leading edge would be a 12.5% cg, meaning you will be using constant up elevator. this will increase drag (reducing both top speed and efficiency) and also you will have to land very, very fast so as not to run out of elevator for the flare. I would recommend 2" back as a good starting place, then move it rearwards from there until it is a little too tail heavy for your liking, then move it forward a little bit. at this point, it should fly level at neutral elevator. good luck!
The wing have 43in wing span 12in root chord and 6.5in tip chord, zero sweep.
francoishaha is offline Find More Posts by francoishaha
Reply With Quote
Old Feb 27, 2013, 11:42 AM
Registered User
Shadrack's Avatar
Winnipeg
Joined Feb 2002
4,218 Posts
Quote:
Originally Posted by francoishaha View Post
Ggtronic, awsome video btw.
I remember the nose ripping of ur polaris, in fact i was watching it from my fatshark google hehe, suddently a bunch of tree apear and then we heard a crack in the wood :-)
We were watching from the side. I remember how dark it was when he crashed.
Shadrack is offline Find More Posts by Shadrack
Reply With Quote
Old Feb 27, 2013, 12:02 PM
Waypoint Collector
TNug's Avatar
United States, NC, Raleigh
Joined Feb 2012
440 Posts
Quote:
Originally Posted by francoishaha View Post
The wing have 43in wing span 12in root chord and 6.5in tip chord, zero sweep.
This is just one of many CG calculators I found Googling.
http://www.friendlyflyers.org/cg-calc.html
Here's the output from your wing dimensions and a 25% MAC:


I believe 25%MAC is still on the nose heavy end of the typical range. Hope it helps.

Cool looking plane by the way. Any details on construction technique, payload, components?
TNug is online now Find More Posts by TNug
RCG Plus Member
Old Feb 27, 2013, 01:08 PM
Mobius Cables... I got em'
chanyote66's Avatar
United States, TN, Oak Ridge
Joined Dec 2011
3,474 Posts
Quote:
Originally Posted by TNug View Post
This is just one of many CG calculators I found Googling.
http://www.friendlyflyers.org/cg-calc.html
Here's the output from your wing dimensions and a 25% MAC:

I believe 25%MAC is still on the nose heavy end of the typical range. Hope it helps.

Cool looking plane by the way. Any details on construction technique, payload, components?
25% MAC as nose heavy??? for such a short wingbase that would be light... And create a more sensitive flight characteristic. I personally would start around 20% and work back as desired.
chanyote66 is offline Find More Posts by chanyote66
RCG Plus Member
Old Feb 28, 2013, 06:42 PM
Psalm 37:4
HawkHunter's Avatar
Litchfield Park, AZ.
Joined Jun 2006
200 Posts
Quote:
Originally Posted by crazy1pilot View Post
Should add a canard!I hope it flys as good as it looks

Crazy1

+1..........A canard would be a good thing!
HawkHunter is offline Find More Posts by HawkHunter
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Show Us your US Navy Ship ! Chophop Life, The Universe, and Politics 68 Sep 18, 2013 12:07 AM
Gallery Show us your plane! (Part 2) skunkworks2006 FPV Aircraft 2585 Dec 09, 2010 11:04 AM
Discussion Show us your fleet. lovegroove FPV Talk 3 Sep 28, 2010 01:42 PM
Gallery Show us your workshop or man cave! TopSecretBoats Racing Boats - Internal Combustion 10 Sep 25, 2010 12:08 PM
Discussion Show Us Your Clumpy Grass Chophop Electric Plane Talk 11 Sep 24, 2010 10:15 PM