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Old Mar 09, 2013, 07:43 AM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
And here is a weight report of the structures.

Rudder - 1.1 g
Fin - 0.7 g
H Stab - 2.1 g
Elevator - 2.9 g
Wing & Hatch - 24.5 g
Fuselage - 39.0 g

This totals to... 70.3 g (or 2 and a half-ish ounces).

The flying weight of my E-Flite Carbon Cub is 90 g. I still might be able to use a Park 180 size motor.
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Old Mar 12, 2013, 11:28 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
Tonight, I installed the receiver, 2 x servos (5g because I had them), a 10A ESC, a Park 180 2200Kv motor, and a 6030 prop. The front of the plane is quite large and masks some of the prop. I may have to make a streamlined nose piece, while I was hoping to make it look like a flat radiator, like the SE-5a.

The fuselage weight increased to 91.5 g... total now at 123.8 g.

A 2S 300 mAh battery runs about 15g... 140g

The carbon cub weighs in at 90g, so I probably need to up the motor and, perhaps, the ESC.
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Old Mar 13, 2013, 12:45 AM
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central AZ
Joined May 2002
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My, that is a good bit of weight for that motor to haul around, based on the numbers I've seen for it. Perhaps a Park250 would better serve your purposes? Just a thought... But it looks very good, I must say!
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Old Mar 13, 2013, 05:46 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
Thanks for the kind words... I wasn't thinking. When I thought about my Carbon Cub's 90 g, I knew better. I've ordered a Power Up 250 plus from HeadsUp RC that should do nicely. I had larger motors but no one in the 250-300 range.

My spreadsheet tells me that for:
-- 40 mph Vmax
-- 2S system
-- 200 g weight
-- 90 W/lb (so 40 Watt system)
-- 1400 Kv at 75% efficiency
-- 7 A Cmotor
--10 A ESC

That I can swing a 7x4 prop with 6 A on the motor. So I will put an 8040 on it and bench test it in case the efficiency is better. At 80% efficiency the 8040 prop should give 20% more power at 7 A. At lower efficiency the current goes up.
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Old Mar 15, 2013, 11:21 PM
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conrad907's Avatar
China, Guangdong, Shenzhen
Joined Feb 2012
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Looking great David!
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Old Mar 19, 2013, 07:19 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
Thanks, Conrad.

I finally got the motor I was waiting on. But, I don't have a prop adapter for a 2 mm shaft; and, the prop keeper I have won't hold the thrust I'm generating... fratzen ratzen, stinken winken...
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Old Mar 19, 2013, 09:27 PM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
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I remember pushrods like that!

Well, nearly like that...

She's looking good.

D
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Old Mar 21, 2013, 02:08 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
I just got the motor rigged up with an EP 8040 and the 2S system draws 5 A and produces 35.5 Watts at WOT. Let me see if I have a 9040!

Edit: I put a 9047 on the motor and it puts out 44 Watts at 6.5 A... I need to adjust the math in my spreadsheet. Now to do some more covering...
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Last edited by davidterrell80; Mar 21, 2013 at 04:25 PM.
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Old Mar 21, 2013, 06:28 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
Finished the basic covering...

To do list:
-- Wing struts and attachment fittings
-- Wing-fuselage attachment fittings
-- Cockpit
-- Pilot, which is also the after wing-fuselage attachment latch
-- Nose block
-- Vent in the electronics bay for cooling air exhaust
-- Landing gear
-- Control horns
-- Windshield
-- Exhaust pipe
-- Guns
-- Markings
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Old Mar 21, 2013, 09:34 PM
Heads up...
RMCCOR7737's Avatar
United States, VA, Stafford
Joined Jun 2009
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Looking great David...
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Old Mar 22, 2013, 05:25 AM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
Thanks!

You may remember from my Blackburn Skua, that my finishing skills are still underdeveloped.

I'm working to do better, this time.

David
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Old Mar 22, 2013, 09:04 PM
UMs & parkflyers... for now.
davidterrell80's Avatar
United States, VA, Herndon
Joined Apr 2012
2,800 Posts
I built the wing-fuselage attach mechanism.

Weight so far is 180.4 grams.
Remaining weight will consist of:
-- landing gear
-- wheels
-- pilot
-- headrest
-- wing struts
-- nose block
-- control horns
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Old Mar 22, 2013, 09:07 PM
Heads up...
RMCCOR7737's Avatar
United States, VA, Stafford
Joined Jun 2009
744 Posts
Quote:
Originally Posted by davidterrell80 View Post
Thanks!

You may remember from my Blackburn Skua, that my finishing skills are still underdeveloped.

I'm working to do better, this time.

David
The Knight is a good plane to improve on with its simple design. Practice makes almost good enough, as I always say....
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Old Mar 22, 2013, 09:52 PM
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conrad907's Avatar
China, Guangdong, Shenzhen
Joined Feb 2012
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The covering looks good David! You are getting close to your maiden, very fast build! This plane looks like it should be a gentle flyer.

Conrad
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Old Mar 23, 2013, 01:40 PM
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dmbaerry's Avatar
United States, NC, Burlington
Joined May 2012
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Looking Great David... will be following.. oh your covering is great.
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