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Old Sep 23, 2012, 01:50 PM
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United States, IA, Keosauqua
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Originally Posted by Tucci View Post
Acetech,

You might be way out of line with that motor recommendation. Punching it into WebOcalc leads to some suprising results.

I think I better read that thread again. (Nevermind, i revisited the WebOcalc thread)

Also I think that while the 10 oz AUW in the plans is a little low, I think 2.4 lbs is on the high side. If this thing goes 16 oz, I'll be surprised.

link to plan: www.indoorflyingmodel.com/Documents/Snapper%20Plan-PDF.pdf

I do have an experienced instructor.....thank God.

Also Bob: What's the flight time on those 800mAh batteries? I'm thinking of going 800 or larger, just to keep it in the air longer that 3 minutes.


Sorry I took so long to respond Tucci--(I've been gone). With the 3S-800 batteries I set my timer to 10 min. on the Blu Baby and 8 min. on the Divinity. Most of my flying is at about 1/2 throttle except for 4 or 5 loops or rolls. Batteries typically read between 11.3 -11.5 v after I land.

Bob
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Old Sep 26, 2012, 06:03 PM
Learn to build with wood.
Tucci's Avatar
United States, NC, Newport
Joined Sep 2012
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Almost ready to cover fuselage, and wing....

Any tips for taking out a small warp in the wing either before or during covering?

The left wing has a slight warp. The outboard trailing edge is lower than it should be. If I wrap a piece of scotch tape from that corner of the wing to the inboard leading edge, I can pull it straight.

I'm not sure how it got warped, it was straight as an arrow a few days ago. I tried sitting it on a flat surface with some weight on it for a couple days, and it didn't make any difference.
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Old Sep 26, 2012, 08:27 PM
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United States, NC, Newport
Joined Sep 2012
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Also, control surface throws..

I'm also looking for recommendations on control surface throws.

Elevator and rudder. Plane has no ailerons.

Looks like right now, maximum deflection on the elevator is 35-40 degrees or so, and the rudder is somewhere between 30 and 35.

This is way too much, right?

Measured with a protractor, with temporary tape hinges.

Anyway, what is good for deflection? Maybe 20 degrees?

I just want to know how much I should dial it down with the Tx.
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Old Sep 26, 2012, 08:55 PM
I think I'm inverted. Maybe.
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United States, CA, Pacifica
Joined Apr 2012
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Got a computer radio? When maidening a plane with large control throws, I normally set dual rates. One at near max deflection (30 degrees), while one at about half that. I attempt a takeoff with the half throws, but if handling is too limited, I flip it back to full throws. If that's on the touchy side, land it, and adjust the throws accordingly.

I don't know the area of your control surfaces, but 20 degrees sounds about right if they aren't too small.
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Old Sep 27, 2012, 01:00 AM
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United States, AK, Fairbanks
Joined Aug 2009
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Quote:
Any tips for taking out a small warp in the wing either before or during covering?
Cover it and then use the covering to get it straight. Basically just give it a twist in the right direction as you apply a little heat, then let it cool, eyeball it, and repeat as necessary. A lightly-built warped balsa wing is no match for the shrinking/pulling strength of iron-on film.
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Old Sep 27, 2012, 01:02 AM
The original Flying Pigs Sqd.
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Netanya, Israel
Joined Aug 2002
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Originally Posted by Tucci View Post
Any tips for taking out a small warp in the wing either before or during covering?
Try spraying some window cleaner liquid on the wing, and twist the offending tip back.
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Old Sep 27, 2012, 01:04 AM
The original Flying Pigs Sqd.
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Netanya, Israel
Joined Aug 2002
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Quote:
Originally Posted by acetech09 View Post
Got a computer radio? When maidening a plane with large control throws, I normally set dual rates. One at near max deflection (30 degrees), while one at about half that. I attempt a takeoff with the half throws, but if handling is too limited, I flip it back to full throws. If that's on the touchy side, land it, and adjust the throws accordingly.

I don't know the area of your control surfaces, but 20 degrees sounds about right if they aren't too small.
That sounds about right. But please, let an experienced pilot fly her first and let him/her decide on the throws for you.
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Old Sep 27, 2012, 07:52 AM
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United States, NC, Newport
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This site is the best.

Thanks for all the help so far. You guys have been awesome.

I'll be using a DX6i (that I scored for $100 NIB ) so I'll be able to set limits and rates to make it flyable.

The control surfaces are big, compared to the size of the plane.

So far, with everything in it but with no covering on it except for the tail assembly, the CoG is right on the money according to the plans, and I have room to slide the battery around for adjustment if need be after it's covered fully.

A friend of mine who has been building/flying for years and years looked at it and said, "Yup, that'll fly."

Doesn't mean I'll be able to fly it, but those were encouraging words.
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Old Sep 27, 2012, 10:15 AM
The original Flying Pigs Sqd.
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Netanya, Israel
Joined Aug 2002
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Large control surfaces on a small model means small throws. To much will stall the plane.

And "Yup, that'll fly" is not proof of airworthyness...
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Old Sep 27, 2012, 11:13 AM
Sure, I can fly after sunset!?
United States, MI, Novi
Joined Jan 2011
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Quote:
Originally Posted by Tucci View Post

A friend of mine who has been building/flying for years and years looked at it and said, "Yup, that'll fly."
I highly suggest that you get him, or someone with experience, to maiden your plane. It is amazing how terrible a plane will fly (and crash?) if only slightly out of trim. You already mention problems with some wing warp. An experienced pilot will (probably) be able to control an out of trim plane long enough to get it trimmed out right. He could also set your DX6i to tame down the plane to a point where you would have success on YOUR maiden.

Another suggestion: Buddy Box!
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Old Sep 27, 2012, 08:37 PM
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United States, NC, Newport
Joined Sep 2012
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Well I covered the wing and most of the fuselage today. I was able to get that warp out during the covering procedure. I shrunk it up some, then straightened the wing and took out the wrinkles while holding the wing straight. Worked good.

I'm not real happy with the covering on the fuselage, but I suppose it's not awful for my first try!

I did not mean that "it'll fly" was proof of airworthiness, just that it was better to hear than "throw it in the trash, you're doomed"

I'm going to spend some time next week buddy boxing on some high wing trainers!

I've also found that the stabilizer assembly is not strong enough for my liking, so I'm going to redesign and build that. I thought the covering would stiffen it up more than it did.
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Old Sep 27, 2012, 08:48 PM
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United States, FL, DeLand
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Remember to glide test it first from a hand launch over tall grass. That will tell you if it is flyable and if you can fly it without endangering the plane. I'd do several hand launches and note trim and responsiveness to control inputs.

One thing you might consider is putting flat plates on the ends of the wings that are the same shape as the wing but present a vertical surface both up and down. That will help the stalling tendencies at the ends of the wings. Also you should twist the wing so that the trailing edge of the outside of the wing is about a quarter inch above level. Twist the wing and shoot it with the heat gun to shrink the covering. That will retain the shape. That's washout, which ensures the inside of the wing stalls first, while the outside remains flying. Makes for straight-ahead stalls instead of falling off on a wingtip and spinning. Spins are bad for you right now...
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Old Sep 28, 2012, 12:33 AM
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Netanya, Israel
Joined Aug 2002
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Redesigning the stabilizer will most likely put more weight in the tail. You already have a long tail movement. That means you'll need more weight in the nose to balance. You'll get a heavier model, with a higher wingload, which will make it fly less "user friendly".

I strongly suggest to leave the tail as is. At the most CA some thin carbon flatrods along the spars. But use CA sparingly. Not for nothing is it dubbed "liquid lead".
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Old Sep 30, 2012, 06:41 AM
Sure, I can fly after sunset!?
United States, MI, Novi
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Quote:
Originally Posted by Up&Away View Post
Redesigning the stabilizer will most likely put more weight in the tail.
YUP!

There is an old saying...

A nose heavy plane flies poorly

A tail heavy plane flies once!
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Old Oct 04, 2012, 01:50 PM
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United States, NC, Newport
Joined Sep 2012
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Redesigned the tail anyway

Ended up ripping the whole back of the plane off, and redesigning the whole thing.
I added 0.1 oz. of weight to the stabilizer assembly but shortened the tail moment slightly to offset that.

The added rigidity is fantastic.
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