Eagler's Nest

Airframes => Double Seaters => Topic started by: ToddK on April 10, 2019, 12:52:18 PM

Title: CG -lengthen tail?
Post by: ToddK on April 10, 2019, 12:52:18 PM
With the info regarding the center of gravity concerns on the Double eagle, is there any consensus about how clean it up a bit?  It seems that pushing the empennage out a few inches might help and be preferable to adding or relocating weight.  Ideas?
Title: Re: CG -lengthen tail?
Post by: MrG on April 10, 2019, 05:30:46 PM
Center of gravity concerns on the Double eagle
That's totally how you look at it when you build it - build to plans you should not have any issues 
If you do what a few of use have done well that's a different story, if you add weight to the front than you need to do 1 of two things
1: Add more weight to rear  
2: Extend rear
with saying that there nearly the same thing with total different out comes  

is there any consensus about how clean it up a bit? (2: best option Extend rear)
There is a lot you can do - wind drag should never be offset with horse power trust me i tried
clean the lines up first, there is a heap of drag from the cabin, both from under were wing attach is and rear of the fuse

You will see with the image i have attached - is my answer to the problem 
Stretching the fuse, gives 2 out comes , 
1: longitudinal stability and we know from ones that have done this already it works
2: Ref the link below - way less drag  

so out come is easy if you have not started, this is a no brainer - now's the time to do it 
i was already about to fly when this info come about, so for me now its chop chop time and head down that path  

This is a good read if you want to do this 
https://www.eaglersnest.com/forum/index.php?topic=1509.30 (https://www.eaglersnest.com/forum/index.php?topic=1509.30)

I cruise around at 65knts (75mph)  im not really after more speed i want a more stable to fly plane and burn a bit less fuel 
plus winter is coming and its a bit cold flying in winter with a cabin i can put a heater in it 

I will post what ive done after i finish the fuse mods
Title: Re: CG -lengthen tail?
Post by: rfeenstra on April 10, 2019, 09:17:53 PM
I added a cabin on my DE extending the wingspan by about 32".  The mod I did greatly improved the stability of the airplane, which suffered because of the extended wingspan.  My tail is 26" longer which made the airplane fly hands off even in slight turbulence.  The flare is greatly improved, partly because the CG is now at about 29-30% MAC, partly because of the additional tail authority.  It flies much better than it did.  Realize that my original build was highly modified from the plans with the extended wing span and the A65 up front.  The streamlined fuselage styled after a champ gave me about 10 mph.  For pics, see my gallery:  rfeenstra
Title: Re: CG -lengthen tail?
Post by: Leonard on April 11, 2019, 03:50:12 PM
Hi ,
I would like to have a picture of your changes.  Leonard
Title: Re: CG -lengthen tail?
Post by: rfeenstra on April 11, 2019, 05:23:07 PM
Hi Leonard.  I have photos in my gallery.  Go to user galleries and find rfeenstra.  The entire build is there with the tail mods being the last few photos.
Title: Re: CG -lengthen tail?
Post by: scottiniowa on April 12, 2019, 08:53:15 AM
  Go to user galleries and find rfeenstra.  The entire build is there with the tail mods being the last few photos.
Rfeenstra,  could you provide a link to your gallery?  I can get to one photo by you, but not a gallery of photos.

Or anyone that can provide how to get to the gallery of photos per poster, and NOT a single photo by such.

And yes, I have gone to "gallery" and tried to do a search via your "rfeenstra" 
Title: Re: CG -lengthen tail?
Post by: Kenny on April 12, 2019, 09:12:41 AM
https://www.eaglersnest.com/forum/index.php?action=gallery;su=user;u=98 (https://www.eaglersnest.com/forum/index.php?action=gallery;su=user;u=98)

Here you go
Title: Re: CG -lengthen tail?
Post by: rfeenstra on April 12, 2019, 09:56:45 AM
Thank you, Kenny!
Title: Re: CG -lengthen tail?
Post by: Kenny on April 12, 2019, 10:13:17 AM
Anytime
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