One Knight in Boston, FF to RC conversion of Bill Hannan design - Page 2 - RC Groups
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Mar 09, 2013, 08:43 AM
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davidterrell80's Avatar
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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Mar 13, 2013, 12:28 AM
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davidterrell80's Avatar
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.
Latest blog entry: Remembering Bob Hoover
Mar 13, 2013, 01:45 AM
Registered User
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!
Mar 13, 2013, 06:46 PM
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davidterrell80's Avatar
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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Mar 16, 2013, 12:21 AM
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conrad907's Avatar
Looking great David!
Mar 19, 2013, 08:19 PM
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davidterrell80's Avatar
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...
Latest blog entry: Remembering Bob Hoover
Mar 19, 2013, 10:27 PM
Visitor from Reality
I remember pushrods like that!

Well, nearly like that...

She's looking good.

D
Mar 21, 2013, 03:08 PM
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davidterrell80's Avatar
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...
Last edited by davidterrell80; Mar 21, 2013 at 05:25 PM.
Mar 21, 2013, 07:28 PM
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davidterrell80's Avatar
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
Latest blog entry: Remembering Bob Hoover
Mar 21, 2013, 10:34 PM
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RMCCOR7737's Avatar
Looking great David...
Mar 22, 2013, 06:25 AM
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davidterrell80's Avatar
Thanks!

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

I'm working to do better, this time.

David
Latest blog entry: Remembering Bob Hoover
Mar 22, 2013, 10:04 PM
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davidterrell80's Avatar
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
Latest blog entry: Remembering Bob Hoover
Mar 22, 2013, 10:07 PM
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RMCCOR7737's Avatar
Quote:
Originally Posted by davidterrell80
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....
Mar 22, 2013, 10:52 PM
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conrad907's Avatar
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
Mar 23, 2013, 02:40 PM
Registered User
dmbaerry's Avatar
Looking Great David... will be following.. oh your covering is great.


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