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Old Oct 22, 2014, 08:19 AM
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United States, NC, Troy
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Originally Posted by IAFoamie View Post
It would be nice to see more of Ed's style of building and more Armin wings here.

IAFoamie
I agree it would be nice to get back to Ed's techniques and $Tree board. There is another thread for the depron stuff, I think.
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Old Oct 22, 2014, 08:25 AM
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Joined Oct 2014
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Triple Axon

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Originally Posted by 7AC View Post
The 2200kv motor is what I had so that is what I used when I couldn't get the cg to balance without ballast and I had the 10 inch prop on hand. (
Hello

I built a "Triple Axon" myself. It is a bit longer than the original and the motor&wing a bit farther away from the tail than EA Axon had. It crashed on launch with both 5"+1 and 7"+2 wings. It acted extremely nose-heavy and I got it to fly a bit with 50% wingchord CG. Before finding this post I thought my motor was tilting the plane too much forward, but I am not sure any more.

Where would you place your CG on 7" wing? How do you choose the location for your wing?
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Old Oct 22, 2014, 11:15 AM
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United States, WI, Oconto
Joined Mar 2013
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This should help

Quote:
Originally Posted by Havardr View Post
Hello

I built a "Triple Axon" myself. It is a bit longer than the original and the motor&wing a bit farther away from the tail than EA Axon had. It crashed on launch with both 5"+1 and 7"+2 wings. It acted extremely nose-heavy and I got it to fly a bit with 50% wingchord CG. Before finding this post I thought my motor was tilting the plane too much forward, but I am not sure any more.

Where would you place your CG on 7" wing? How do you choose the location for your wing?
Aircraft Center of Gravity Calculator
http://adamone.rchomepage.com/cg_calc.htm
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Old Oct 22, 2014, 03:59 PM
Whoa……it flies
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Australia, VIC, Geelong
Joined Feb 2007
177 Posts
Quote:
Originally Posted by iwlf View Post
I agree it would be nice to get back to Ed's techniques and $Tree board. There is another thread for the depron stuff, I think.
This IS the thread for depron EA inspired designs, as well as all other types of foam board, including obscure regional variations like $Tree board.

The Professor of EA Uni himself uses depron for tail parts and references depron techniques in the very first post (BENDING DEPRON AND UK FOAMBOARD by Wayne's RC) and more recently my depron Armin wing build video.
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Old Oct 23, 2014, 09:29 AM
What could possibly go wrong?
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Market Harborough
Joined Apr 2006
3,741 Posts
Quote:
This IS the thread for depron EA inspired designs, as well as all other types of foam board, including obscure regional variations like $Tree board.

Thanks for that A.N. For me the clue was in the title. EA got this thread off to a great start with his fine models. Since then there have been all sorts of ideas, insights, help and inspiration etc. I wasn't the first to post semi scale models here. I've been doing it for a couple of years now.

I'd be the last person to try and hijack someone else's thread, but I still think Depron qualifies as foamboard and "university" implies variety and breadth.

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Old Yesterday, 11:01 AM
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United States, ME, Bar Harbor
Joined Jun 2011
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Peace Drone used in Syria ......to help people!!!!!! You go Ed! Awesome. You never know how you designs could be used. I never imagined......

Delivering food to refuges at night when the bad guys can't see the peace drone fly.

http://diydrones.com/profiles/blogs/...-a-new-mission
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Old Yesterday, 03:29 PM
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Quote:
Originally Posted by fl_rider View Post
Aircraft Center of Gravity Calculator
http://adamone.rchomepage.com/cg_calc.htm

Hi,

I have seen many of Ed's excellent video tutorials for construction techniques. (Many thanks Ed! - it's lots of fun.) From what I understand in the videos the wing spar is placed at a point about 1/3 of the way back on the fuselage and then the plane is balanced so the CoG is around that point.
So if the fuselage is 36 inches long then the wing spar is placed at 12 inches behind LE of fuselage and CoG is balanced there.

Some one please correct me if I'm wrong but I "think" based on the Aircraft Center of Gravity Calculator you can put the wing anywhere on the fuselage and then balance the plane to the calculated CoG. This CoG can be anywhere - on the wing or off the wing. This calculator takes into account the distance between the LE of the wing and the stabilizer; it does not care about the length of fuselage ahead of the LE of the wing.

Anyways I have the same question as well and a bit confused on how to go about positioning the wing and getting the CoG... can anyone please clarify?

Thanks.
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Old Yesterday, 04:51 PM
What could possibly go wrong?
nickchud's Avatar
Market Harborough
Joined Apr 2006
3,741 Posts
Quote:
Originally Posted by goodkebo View Post
Peace Drone used in Syria ......to help people!!!!!! You go Ed! Awesome. You never know how you designs could be used. I never imagined......

Delivering food to refuges at night when the bad guys can't see the peace drone fly.

http://diydrones.com/profiles/blogs/...-a-new-mission
Absolutely bloody fantastic! go Ed
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Old Yesterday, 05:52 PM
What could possibly go wrong?
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Market Harborough
Joined Apr 2006
3,741 Posts
Hi Dropout

This website is really helpful. The way I see it, where pitch is concerned, a plane is a see-saw. There's a fulcrum somewhere and all the upward and downward forces act around there. Weight works down vertically always and it's usually assumed to operate as if all of it is through the Centre of Gravity.

Lift is more complicated. It works upwards at right-angles to the wing, not always at right angles to the horizon. And when it stalls it doesn't work at all. That usually happens when the angle of the wing against the angle of the airflow (Angle of Attack) is about +12 to15 degrees. But lots of things affect that number. If the Angle of Attack is close to zero then :
Quote:
It has been found both experimentally and theoretically that, if the aerodynamic force is applied at a location 1/4 from the leading edge of a rectangular wing at subsonic speed, the magnitude of the aerodynamic moment remains nearly constant even when the angle of attack changes.
This location is called the wing's Aerodynamic Centre AC.
Going back to the see-saw, if the downward force is equal and opposite to the upward force around the fulcrum, you'll get stability. A long fuselage with a small "horizontal stabiliser" can have the same effect on pitch as a short fuselage with a larger one. Canards have the main lifting wing behind, but the principal is the same except: With any plane you want the front of the plane to stall first so that the angle of attack goes back towards zero, the nose drops and speed increases. This means you want the canard wing to be doing more than its fair share of lifting. You have to take that into account when working out where to put the Centre of Gravity.

At this point, it's best if I stop boring you and suggest you visit a specialist website like the one I've recommended above. Hopefully, you've been bitten by the bug of this puzzle and you will soon find there are thousands of possibilities, thousands of different kinds of planes to solve the basic puzzle in different ways. Go for it.

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Old Yesterday, 08:47 PM
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Canada, BC, Sicamous
Joined Jun 2012
31 Posts
I managed to finally maiden my plane today. I called it the Albatros. The wings are full sheets of Dollar Tree foam board. The motor batteries are 2 2200 mAH Nanotechs and a 750 for the video transmission and camera. It has a basic pan and tilt board camera in the center pod and a fixed mobius above it. All up weight is 3.5 pounds. The motors were the cheapest turnigys HK sells at $6 each. With a 8x4.3 on them they make 3.2 pounds of thrust between them. My launch was awful and ended up with about a 75 degree climbout. I got it settled down and trimmed out and it ended up being a nice plane to fly. It has far more power than my Bixler, but I'm not sure if its quite as floaty. The wing is 60 inches but it weighs 3 times as much. Anyways I'm happy with it. I hope I get as much time in the air with it as I did my Bix. I likely have 100 hours of flight with that thing and it's getting pretty tired.
One question I have for you guys is there a stronger way of securing parts together such as the fuselages to the wings than the 3M two way tape or hot glue? I used the tape and for a 3 and a half pound plane it doesn't inspire confidence.
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Old Yesterday, 09:57 PM
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United States, MO, Stockton
Joined Oct 2013
665 Posts
albatross

looks neat enough I'm building a foam version of an ugly stick, about a 25 size,, 50" wing, 7" chord, the fuse is 36, I'm powering it with a turnigy I had from a converted sporster, It'll probably be too much motor, it'll weigh about half of what the sporster did about 2 lbs loaded would like to have it done by sunday but I doubt it sam
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Old Today, 09:04 AM
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Joined Feb 2014
47 Posts
Quote:
Originally Posted by nickchud View Post
Hi Dropout

This website is really helpful. The way I see it, where pitch is concerned, a plane is a see-saw. There's a fulcrum somewhere and all the upward and downward forces act around there. Weight works down vertically always and it's usually assumed to operate as if all of it is through the Centre of Gravity.

Lift is more complicated. It works upwards at right-angles to the wing, not always at right angles to the horizon. And when it stalls it doesn't work at all. That usually happens when the angle of the wing against the angle of the airflow (Angle of Attack) is about +12 to15 degrees. But lots of things affect that number. If the Angle of Attack is close to zero then :


Going back to the see-saw, if the downward force is equal and opposite to the upward force around the fulcrum, you'll get stability. A long fuselage with a small "horizontal stabiliser" can have the same effect on pitch as a short fuselage with a larger one. Canards have the main lifting wing behind, but the principal is the same except: With any plane you want the front of the plane to stall first so that the angle of attack goes back towards zero, the nose drops and speed increases. This means you want the canard wing to be doing more than its fair share of lifting. You have to take that into account when working out where to put the Centre of Gravity.

At this point, it's best if I stop boring you and suggest you visit a specialist website like the one I've recommended above. Hopefully, you've been bitten by the bug of this puzzle and you will soon find there are thousands of possibilities, thousands of different kinds of planes to solve the basic puzzle in different ways. Go for it.


Yes - I agree there are many possibilities.
I made a version of the Axon with a 40" kfm3 wing and COG was actually around 4-5 inches back from LE of wing. The wing chord was 7 inches.
It flew pretty well - I mean I was able to go home with the plane fully intact 😃.
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Old Today, 09:12 AM
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Joined Feb 2014
47 Posts
Oops I hit reply button to quick ...
Only thing is the plane flew with a bit of an up angle with respect to the horizon.
Maybe it was the CoG location or it wasn't moving fast enough or I had the elevator engaged or a combination of things...
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