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Old Sep 28, 2008, 08:43 PM
Tinkerer
jfhspike's Avatar
RI
Joined May 2005
184 Posts
Quote:
Originally Posted by Tony65x55
Hi Speeddemon, welcome to the BB thread. We'll get you flying in no time, that's what we do here. Tony
Speeddemon-
Right now my son and I are building a 33, and taking pictures along the way. We'll be using a 2805 from HobbyCity rather than the CDRom motor like you, but otherwise it should be pretty easy to follow along together. First step is definitely to get some fan-fold at Lowes if you can, and cut out the parts. For the monoblock, we're using some 1.5" foam that I picked up from a job site -- they were insulating SOMEthing and I grabbed the scraps. Since 1.5 is neither 1 nor 2 inches, we had to re-cut the top and bottom pieces...but that's the only change.

When you cut out the parts (esp. the two wings and two fuselage sides), you'll notice that your fan-fold has a sort of "skin" on one side. Tape the fuselage plan to that side, and cut out one fuselage-side. Then FLIP the fuselage-plan over and lay it down, again on the skin side of the fan-fold, and cut out the other piece. The result? Two fuse-sides that will have skin on the outside, and raw foam on the inside.

For the wing, do the same thing: the plans give you the shape for one half of the wing. Cut that, and then flip the plan over and cut the other half; now you have two half-wings, each with the skin on the top. (If it seems as if the skin's on the bottom, flip both over...it'll work!).

Cut neatly, use a ruler and an exacto, and if you get a cut that's a little rough -- some torn foam -- put in a new blade. Get all those FF parts cut out, and label them, and call it a night.

On the same evening, see if you can find a friend who has a bandsaw. THere's nothing like it for cutting out the monoblock.

* When you cut the monoblock, I suggest that you omit the narrow slot for the landing gear -- there's a better design available involving sort of spring-loaded landing gear, and we can talk you through that.

* As you'll see in the attached pics, we decided to experiment with an extended monoblock. Not at all necessary, but seemed like it'd give us a good place to mount the servos.

More pics/hints later. Keep us posted on progress.

Summary of tools used so far:

*X-Acto knife and about 3 blades
*Electric drill (for making holes in monoblock, but knife would work too)
*Clear packing tape; I like the slightly-stretchy, quite heavy variety for making hinges.
*Long straightedge
*Ballpoint pen
*We also used a ruler with a thin metal insert, but could have used the straightedge instead. We used the ruler to measure 1.5" as well. :-)
*Solder/soldering iron to put bullet connectors on the ESC and motor
* Wire-cutters
* I used a nifty little bevel-cutter to do the V-slot for the hinges, but I've done it with a hand-held exacto knife as well, and it comes out fine.
* Friend's bandsaw for cutting out monoblock; could also be done with careful use of a multi-blade utility-knife (available at a local Dollar Store), which can be extended to give you a utility-knife with a 3-inch long blade. Harder to get all the cuts perpendicular, but since all that matters is that the SIDES are parallel, this isn't a big deal.
* Needlenose pliers for bending a zig-zag in the music wire to fit the servo arms
* Jeweler's screwdriver (philips) for putting the screw into the arm on the servo.

Materials so far:
* one sheet of fan-fold protection board
* (Packing tape)
* Some 1.5" in blue foam (1" or 2" pink foam is fine, too!)
* A table or piece of scrap on which you can cut with an X-acto knife without annoying anyone.
* Receiver, two lightweight servos, an ESC, and my 2205 motor, bullet connectors and heat shrink, and
* two pieces of .039 piano wire (next size larger would work too, but would be heavier)
-John
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Old Sep 28, 2008, 09:03 PM
If it flies, its cool
bondohead's Avatar
Atlanta
Joined Apr 2007
1,114 Posts
great log so far! im going to show your pics to a noob in anothetr thred
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Old Sep 29, 2008, 01:54 AM
If it flies, I will crash it
mxspode's Avatar
USA, CO, Westminster
Joined Jan 2008
3,017 Posts
Quote:
Originally Posted by bondohead
ive ben following the phlat printer thred (sort of) i hadnt herd no plans. are you sure? what are mark and wife charging for the kit?
The "Bones" kit they are selling for $140 plus $30 for shipping. Not to bad really. Of coarse from there you need to buy all of the electronics and steppers and so on plus a Comp to run it. The Premium, kit is $628 plus $70 shipping. I have all of the material in the shop if they still sold the planes.

Oh well, I am just a few days to late. Now I will have to wait a little longer. If I could just talk a couple of people into paying for it.

Rob...

Edit; Link to Phlatprinter purchase page.
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Old Sep 29, 2008, 03:54 PM
Foam Fighter and a Bloody Mick
grenadapult's Avatar
Hermann, MO
Joined Jul 2008
386 Posts
Quote:
Originally Posted by jfhspike


"On the same evening, see if you can find a friend who has a bandsaw. THere's nothing like it for cutting out the monoblock."

I have an external garage, about 200ft down a STEEP hill, so I get kinda lazy about going down to use the bandsaw. At least i used to, until I cut 2 monoblocs with a blade, then did one with the bandsaw! Amazing difference!

"When you cut the monoblock, I suggest that you omit the narrow slot for the landing gear -- there's a better design available involving sort of spring-loaded landing gear, and we can talk you through that. "

Please hurry along with the walkthrough on this one, its what I'm planing for my Pirahna!

"I used a nifty little bevel-cutter to do the V-slot for the hinges, but I've done it with a hand-held exacto knife as well, and it comes out fine."

I got tired of everything I tried looking terrible, and finally started sanding my bevels. it takes a long time, but the come out close to perfect. Where did you get the "nifty bevel cutter", and could you incude pics of it?

"A table or piece of scrap on which you can cut with an X-acto knife without annoying anyone."

You didn't miss ANYTHING!!! My wife was pretty angry about her tablecloth getting a 7 inch slash in it.
I have already built 2 BB33's, yet i can't wait to see the rest of your log. I have never seen so much detail and "how-to" on here. Even the build guides posted with plans aren't THAT detailed. As far as the noobs are concerend, you are a godsend. I hope at least a link to your post gets put on page one.

Keep up the good work!
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Old Sep 29, 2008, 05:28 PM
I just want to fly
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USA, IN, Jeffersonville
Joined Aug 2008
690 Posts
Thank you mxsplode i have mine built ill post pics hopefully she will fly!
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Old Sep 29, 2008, 06:05 PM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Quote:
Originally Posted by grenadapult
I have already built 2 BB33's, yet i can't wait to see the rest of your log. I have never seen so much detail and "how-to" on here. Even the build guides posted with plans aren't THAT detailed. As far as the noobs are concerend, you are a godsend. I hope at least a link to your post gets put on page one.

Keep up the good work!
I agree with you, Grenadapult.
Excellent stuff. I'm from the "Hack-n-Slash" school of building and seeing your attention to detail makes me ashamed, jfhspike. Though probably not enough to significantly change my building methods. You should consider putting a tutorial in a blog or something. Your instruction would be a welcome addition for new modelers and a good review for those with experience.

Which prompts me to ask a question to all of you. Do you build so you can fly, or do you fly so you can build?
For me, it seems I build so I can fly and I crash so I can build.

The maiden was a disaster. I had hot-glued the elevator horn over the hinge tape and it pulled loose in flight. I got her up to about 50 feet then straight down on the nose in rocks. The duration of controlled flight was about 12 seconds. I put in a little rudder trim then...

Sorry no pictures.

Steve.

PS. I may start drinking again. Nahhh!!!
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Old Sep 29, 2008, 11:15 PM
Tinkerer
jfhspike's Avatar
RI
Joined May 2005
184 Posts
More build log

Quote:
Originally Posted by justwanttofly
Thank you mxsplode i have mine built ill post pics hopefully she will fly!
I see that my target audience has raced ahead of me...but I'm still going to continue with details/photos. By the way, you often see my hands in the photos, but that's because my son likes using the digital camera. Rest assured that he's involved in the building as well.

A couple of folks asked about the landing gear I was planning to make. This post http://www.rcgroups.com/forums/showp...postcount=5449 explains it very nicely, and this one
http://www.rcgroups.com/forums/showp...postcount=6369 gives details and drawings. I've included my own photos, but those prior posts are probably better anyhow.

Today's steps: wing stiffening bamboo skewers, fuselage sides onto monoblock, velcro "strap" for battery bay, routing of control rods, top and bottom and stabilizers (horiz and vert) glued into place, landing gear.

Supplies in addition to yesterday:
* bamboo skewers, about 1/8" diam
* spray adhesive (but you can use hot glue, or polyurethane, or epoxy, or ...)
* scotch tape
* "Hook" velcro, about 6", without adhesive
* Loop velcro, about 1" and 3", with sticky back.
* One old credit card
* A couple of rubber bands
* Some stiff music wire; I've seen 1/16" (which means at least .063) recommended. I'm not sure what mine was; I just used the thickest I had on hand.
* Two popsicle sticks
* One coffee-stirrer tiny straw
* Some hot-melt glue

Tools in addition to yesterday:

* teakettle
* needlenose pliers
* hot-glue gun
* wire cutters.

I'll let the pictures tell most of the story.

Hints on wire work: don't try to cut through piano wire. Instead, cut it a little, and then bend quickly; it'll usually snap at the cut-mark.

For figuring out where the wire will come out through the fuse sides and top, we just taped things in place, more or less, and made a decent guess. The wire's flexible enough to forgive some error here.


* Added a "rear wheel" in the form of a bit of skewer sticking down the back.

* Added stiffening bamboo rods on the leading and trailing edge of the wing, to prevent the fold-up problem. Small mistake here: now the wing no longer fits the saddle, because it's 1/4" longer (bow to stern) than it used to be. We'll have to enlarge both ends of the saddle a tiny bit to accomodate.

* Although we used spray adhesive for the vertical stabilizer, it just didn't adhere very well. A 5" long, 1/4" wide glue strip just isn't a lot. So I ran a thin bead of hot-melt down the side. If it still seems flimsy, I'll steal an idea from gpw's "Trainer-One" and put a diagonal piece of skewer, about 3" long, from the vertical to the horizontal stabilizer, to strengthen it.

I'm sure that even with all these details, I've forgotten to say some stuff.

Two main ideas:

* Build light. You can add weight later, in the form of hot-glue repairs, etc., but it's very hard to remove it.

* Build inventive: you don't have ot use the same music wire I did, or the same glue (but polyurethane and spray-adhesive are both nice and light!). You can use something other than a credit-card in making the landing gear base. You can use a drill-bit rather than a scrap skewer in your drill. You can skip the landing gear completely if you like. It'll still fly (on grass!).

I guess that I left out two steps: figuring the angle for the motor mount, and attaching the motor. More on these, if I remember, tomorrow.

-John
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Old Sep 29, 2008, 11:59 PM
I just want to fly
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USA, IN, Jeffersonville
Joined Aug 2008
690 Posts
very nice build log jfhspike.i was talking about my KFM3 wing for my BB42. i have pics of it a few pages back..i have crashed it over 20 times and it is still is 1 piece ive had to do some maintenace here and there but no real damage to fix..i tried to do a loop remeber this is a 42 no spar in my UC wing.
i did a nose dive to pick up some speed for the loop and my wings folded it fell from 60 feet and no damage. Tonys monoblock is the best for these foamies everytime i crash and no damage i thank tony lol..i had a parkzone j3 cub 6 crashes i had to replace everything i didnt i just built my BB.Now ive gotten good enough that i start in a parking lot across the street to taxi dodge a few light poles and trees and start flyig in the feild its sweet i just built my KFM3 wing but my new servo hitec hs55 for my alirons just didnt work but i put them flat as i could and used elevator and rudder it cut right through the wind it was sweet.. i Love my BB.. its time to build a 60 now
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Old Sep 30, 2008, 12:15 AM
If it flies, I will crash it
mxspode's Avatar
USA, CO, Westminster
Joined Jan 2008
3,017 Posts


These Foam board cutters are real nice. They allow you to cut the foam perfectly square and it is very handy when you have two identical parts such as the fuse sides. Just pin two pieces together and set the depth of the cutter to cut both. One thing I have noticed if you are the picky type. If you cut all of the way threw the foam with the cutter it will tend to "wade up" the foam on the underside. To avoid this I actually set the depth so it cuts almost all of the way threw and then finish with a single edge razor blade or an exacto knife.

The perfect 45 degree angles are another nice feature. I usually cut the angels first before I cut the rest of the out line. Even on parts that are shown attached in plans. Just cut the bevel and then re-cut the square cut on the same line or the reverse for big throws.

It is a good tip and a very nice tool. I rarely cut foam without it.

Rob...
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Old Sep 30, 2008, 06:24 AM
Glue-it-again-Ben!
blxpy's Avatar
Adelaide, Australia
Joined Apr 2008
813 Posts
Flew my new BB today with the Kfm3 wing that I accidentally set with only 3/4 inch dihedral per side.

It flew fantastically well!

Less twitchy than my UC BBs, and more than maneuverable enough. I'm not saying you'd get it around in a basketball court, but outdoors with some air space no problems. I'm sure I'd have no trouble bringing it down inside a soccer field for a few laps on the way to landing.

It's my first Kfm BB, and I have to say I'm really pleased with it. This is much more my style than the UC wing. Fast, efficient, and super smooth. Mine pulls unlimited vertical with Blue Wonder 1300 kva, 800mah 3 Cell and GWS DD 9x5 prop. It sat really well in a bit of a breeze today which is really pleasing.

This is my 3rd BB, and is by far my favorite. Stall speed is a little higher than the UC wing, but for me the benefits outweigh that. I tend to fly between 75 and 100% throttle anyway. If you haven't tried a Kfm3, Go for it!
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Old Sep 30, 2008, 07:55 AM
Foam Fighter and a Bloody Mick
grenadapult's Avatar
Hermann, MO
Joined Jul 2008
386 Posts
Spectacular build log again. Seriously, i would love tose that all compiled into one post somewhere. then i could print it out along with the plans, and drop it off with some foam for a buddy of mine who's beeen "gonna build a plane" for some time now. I may tryto build that Landing gear tonight.

Thanks, Spike!
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Old Sep 30, 2008, 08:24 AM
Jack
USA, ME, Ellsworth
Joined May 2008
16,699 Posts
blxpy,

Congrats on the KFm3 maiden. That wing design is amazing.

Your description of the KFm3 wing sounds like it is exactly like mine as far as dihedral and performance. You are obviously a better flyer than I am if you're running it at high to full throttle and staying with it.

I have had to fall back to a KFm2 (the KFm wing shown on the BB 33 plans) with 2" dihedral and no ailerons to better match my abilities. But that is still a very maneuverable plane. It does not have the "snap" on rolls but it is a good advanced RET trainer.

The KFm2 with more dihedral has better directional stability and will fly itself hands off pretty much once it is trimmed out. Even do a hands off recovery if you have enough altitude.

My KFm3 wing had to be flown pretty much full time. I'll get back to flying it eventually and I'll bet it will be more fun when I get where I can handle it. My son is a good flyer and he loved the BB with KFm3 wing, it was fine for him.

And I second your vote on the motor and prop combo too. I'm using a 2410-12D, 1200KV, 55 gram motor from lazertoyz and getting the same kind of performance. We had a storm through here over the weekend and yesterday there were winds of 10-15 MPH and gusting a little higher when I flew and the BB let me handle those fine. Lots of stick movement, having to throttle up and down for up and down wind, and really keeping your head into it. Great training and fun too.

I went with the heavier motor because I was replacing an apparently defective motor of a similar weight and wanted to keep the CG about the same. I think the BB's with the KFm2 and KFm3 wings really come alive with a little more motor than the 24 gram motors. I like having more power than I really need available and flying throttled back.

Jack
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Old Sep 30, 2008, 12:49 PM
Registered User
Canada, MB, Oakbank
Joined Dec 2004
657 Posts
Hi there all. I am just about finished fixing my BBY33 and need a bit of help. I could not remember which side stick the rudder goes on. I unplugged all electronics and forgot to write it down. I have throttle on the left stick and elevator on the right. I know this is a stupid question, but I cannot remember. Thank you all.
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Old Sep 30, 2008, 12:54 PM
Foam Fighter and a Bloody Mick
grenadapult's Avatar
Hermann, MO
Joined Jul 2008
386 Posts
Quote:
Originally Posted by NEW222
Hi there all. I am just about finished fixing my BBY33 and need a bit of help. I could not remember which side stick the rudder goes on. I unplugged all electronics and forgot to write it down. I have throttle on the left stick and elevator on the right. I know this is a stupid question, but I cannot remember. Thank you all.
Its quite alright. After years of 2 channel rc cars, i had trouble with it as well. The rudder goes on the left stick, Ailerons on the right. perhpas a good way to remeber is "right=ons" (Ailerons, elevons) LOL!
And to date, I still fly mostly with Ailerons.
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Old Sep 30, 2008, 01:18 PM
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Toronto, Canada
Joined Feb 2002
151 Posts
Hi Tony
I drive by Oshawa every other weekend. Where is the Lowes out there and do they have FFF?
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Old Sep 30, 2008, 01:36 PM
Tinkerer
jfhspike's Avatar
RI
Joined May 2005
184 Posts
Quote:
Originally Posted by NEW222
Hi there all. I am just about finished fixing my BBY33 and need a bit of help. I could not remember which side stick the rudder goes on. I unplugged all electronics and forgot to write it down. I have throttle on the left stick and elevator on the right. I know this is a stupid question, but I cannot remember. Thank you all.
It's true that ailerons go on the right stick and rudder on the left...when you have both. When you have only rudder, I think that many people put it on the right stick, so you get used to the idea that the right stick is used for turning; when you move to an ailerons-and-rudder plane, you still do your turns with the right stick, but learn to use a little rudder to make things work out. [But I'm no authority here...I'm sure others can jump in to correct me on this.]

-Spike
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Old Sep 30, 2008, 01:40 PM
Tinkerer
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RI
Joined May 2005
184 Posts
Quote:
Originally Posted by justwanttofly
very nice build log jfhspike.i was talking about my KFM3 wing for my BB42.
My bad! I saw "justwanttofly" and thought "that jammed-together name is the one who's starting a build," when it was REALLY "speeddemon." So perhaps my intended audience is still reading along.

Last installment later tonight; we flew the plane this morning in the backyard, and it was a pleasure, except that

* we have much more power than we need (and the 3S 1500mAh battery is more weight than we need, too -- switching to the 2S-1200 or 2S-700 should improve things a good deal)
* we needed to reduce the throws a LOT
* You just can't use landing gear with small wheels in grass

I assume that when I get home from work, I'll find out that my son's been doing some more flying and has things all figured out.

--Spike
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Old Sep 30, 2008, 02:00 PM
AKA Don
bz1mcr's Avatar
United States, MI, Houghton Lake
Joined Dec 2002
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Quote:
Originally Posted by NEW222
Hi there all. I am just about finished fixing my BBY33 and need a bit of help. I could not remember which side stick the rudder goes on. I unplugged all electronics and forgot to write it down. I have throttle on the left stick and elevator on the right. I know this is a stupid question, but I cannot remember. Thank you all.

It is commom practice for those flying 3 channel RET airplanes to put the rudder on the right stick. So, you have R and E on the right and throttle on the left.

4 channel planes using mode 2 are A and E on right and R and T on left.
Don
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Old Sep 30, 2008, 02:41 PM
Registered User
Canada, MB, Oakbank
Joined Dec 2004
657 Posts
Thanks all for the help. Once this cold is over will be back up.
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Old Sep 30, 2008, 02:42 PM
Registered User
Canada, MB, Oakbank
Joined Dec 2004
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One more question. Would a three channel remote( such as one with a Slo-V) work. I mean one with a sliding throttle on the left and R/E on the right? I was thinking that I may strip it out of my Slo-V for a second BBY.
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Old Sep 30, 2008, 03:01 PM
AKA Don
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United States, MI, Houghton Lake
Joined Dec 2002
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Sure, that should work fine for a RET BBY.
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Old Sep 30, 2008, 03:05 PM
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United States, NY, Kings
Joined Feb 2006
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Quote:
Originally Posted by bz1mcr
It is commom practice for those flying 3 channel RET airplanes to put the rudder on the right stick. So, you have R and E on the right and throttle on the left.

4 channel planes using mode 2 are A and E on right and R and T on left.
Don
What I did with my Optic 6 is I programmed a mix Aileron->Rudder and reduced rudder rate. That way, if I put kfm3 wing on, I fly normal mode 2. If I put UC wing on, I just flip the Rudder Dual Rate switch and control feels pretty much the same - you roll with right hand and feed a little left hand for coordinated turn.

Sergey.
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Old Sep 30, 2008, 07:59 PM
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RI
Joined May 2005
184 Posts
Build log, part 3 (final part)

We finished up the BB this morning. Final steps:

0. Paint bottom of wing using Krylon fluorescent yellow and pink for visibility.
Nothing special here -- just a light coat of paint from 8" away, after testing that it didn't attack the foam substantially. I used some masking tape and newspaper to make stripes.

1. Adjust wing saddle to make room for bamboo skewers on wing.
I just cut out 1/8" extra at each end. At the same time, I marked the CG limits, from 2.3 to 2.6 aft of the leading edge of the saddle (before I extended it!)

2. Install control horns
Just small scraps of plastic I had lying around. Credit card would be equally good. My son melted holes for the control wire by heating a scrap of control wire with a lighter until it glowed red and then spinning it as he pressed it through the plastic piece. The control horns were about 1/2" x 1", and we cut a slot for each in its control surface, all the way through to the other side, and put a little hot-glue on as we pushed the horn into place, and a little more on each side of the control surface for good luck. The horn tilts forward so that the hole for the wire is right at the hinge line, although this is not as important as some people would insist . The important thing is "how far from the control surface is the hole?" If it's 1/4" away, you'll get HUGE movements. If it's an inch away, you'll get too little. We went with about 3/8" - 1/2", but should have gone for maybe 3/4; as it was, we had to adjust the rates on the xmitter to 30% to make it fly well.

3. Test CG (center of gravity) and worry that it's too far aft.

This part's easy: you just attch the wing with some rubber bands and put a finger under the plane and find the balance point, then see whether it's pretty near the marked center of gravity.

4. Trim control wires to proper length and put Z-bends at control horns; removing all that wire at the back end moved the CG forward so that all's well.

We forgot to put the V-notch (for adjusting) into our wires, but that's OK because (a) I bent them pretty well, and (b) we used a small "trim" adjustment in the xmitter to compensate for my forgetfullness.

5. Test all electronics; make a notch in the vertical stabilizer to hold the antenna.

You can see the notch in the picture. We did the "idiot test" first: "Can the antenna, coming out the back under the wing, actually reach the prop? Because if it can, it will." Alas, it could. So we made the notch to hold the wire back. A dab of hot glue would have been a good thing too, but I skipped that.

As for testing the electronics, we found that both servos needed reversing, and that the prop centering-ring needed a little adjusting to make it fit the propsaver. It would start out OK, but slip about 1/16" to one side, and then the vibration was HORRIBLE. Found the right centering ring, and all was well.

6. Measure all up weight, without battery.

We got 6.3oz for the fuselage (including landing gear) and 1.55 oz for the wing. I think that I should use heavier wire on the gear, though, so maybe add .5 oz. So: all up weight as built: 7.9oz; all up weight if we'd used the right wire: probably 8.4oz.

7. Replace landing gear rubber bands with others, and hang them from the wing-hold-down peg, because it felt better.

8. Test glide and fly!

Supplies:
* Newspaper (not required)
* Masking tape (not required)
* Krylon fluorescent spray paint (not required)
* Small model-scale (not required)

Tools:
* No new tools used.

Results: it flies great. With the 2805 motor from Hobbycity, it's overpowered on 3S (and the 3S-2000mAh battery is too heavy). With 2S-1200mAh, it's a peach. My son flew it a lot this afternoon, and reported "It was totally awesome. I could make it climb up at about 45 degrees, up to twice the height of the big trees in the backyard, and Luke and I flew our blue-babies around together and had lots of fun." (Luke is a neighbor kid who's also build a BB). They also set the elevator rates back to a little larger (60%, perhaps), but kept the rudder rates small.

Summary thoughts:

* If I were doing it again (and I probably will be!), I'd use the spray-glue for the monoblock-to-sides joint, but on the top-to-sides and bottom-to-sides joints, it didn't hold as well as I'd like, and we had to do a little bit of after-thought patching with hot glue. Maybe next time I'd use polyurethane. I'd also remember to put in the V-notches in the control wires. The extended monoblock seems like a keeper of an idea.

* I don't like the vertical stabilizer attachment. 4 inches of 1/4-wide glue-strip just doesn't seem like enough (and in our case, it started to fail before we got going, so I re-glued with hot-melt). I'd like to see a little re-design in this area of the plane.

* In fact, getting the tail right is more of a pain than I'd like. For flying, this plane is terrific. For BUILDING, I think that GPW's Trainer-One is a little easier for someone who's never built before. It'd be nice to figure out a few tweaks to help THIS plane be as easy to build as the T-1.

* I'd also make the saddle a straight-line, and build an adapter from the undercamber wing to the saddle, so that I could swap it out for a KFm3 later, as others have described. I'd have done that this time, but I forgot.

* Finally, if I weren't in such a hurry to fly, I'd spend some time sanding a few rough edges and painting the whole plane.

THANKS, TONY, for a great design!!

--Spike

PS: Tuppertn: mMaybe when you return we can show you this BB. We're just a few miles up the road from Newport.
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Old Sep 30, 2008, 08:10 PM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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Spike,

Nice build log. I really like the built in velcro strap battery retainer. Will use in future builds.

Ken
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Old Sep 30, 2008, 10:08 PM
Glue-it-again-Ben!
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Adelaide, Australia
Joined Apr 2008
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Well done on the build log spike. Excellent for the first time builder, and there's also great new ideas/techniques there for us all to try.

When the BB index gets compiled I'm sure your Log will be a major feature.

Ken - with your inbuilt velcro, try joining in a piece of elastic between the two bits of velcro. It gives you nice tension actually pulling the battery against the mono-block. Works a treat with mine.
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Old Oct 01, 2008, 02:36 AM
Glue-it-again-Ben!
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Adelaide, Australia
Joined Apr 2008
813 Posts
Quote:
Originally Posted by jackerbes
blxpy,

Congrats on the KFm3 maiden. That wing design is amazing.

Your description of the KFm3 wing sounds like it is exactly like mine as far as dihedral and performance. You are obviously a better flyer than I am if you're running it at high to full throttle and staying with it.

I have had to fall back to a KFm2 (the KFm wing shown on the BB 33 plans) with 2" dihedral and no ailerons to better match my abilities. But that is still a very maneuverable plane. It does not have the "snap" on rolls but it is a good advanced RET trainer.

The KFm2 with more dihedral has better directional stability and will fly itself hands off pretty much once it is trimmed out. Even do a hands off recovery if you have enough altitude.

My KFm3 wing had to be flown pretty much full time. I'll get back to flying it eventually and I'll bet it will be more fun when I get where I can handle it. My son is a good flyer and he loved the BB with KFm3 wing, it was fine for him.

And I second your vote on the motor and prop combo too. I'm using a 2410-12D, 1200KV, 55 gram motor from lazertoyz and getting the same kind of performance. We had a storm through here over the weekend and yesterday there were winds of 10-15 MPH and gusting a little higher when I flew and the BB let me handle those fine. Lots of stick movement, having to throttle up and down for up and down wind, and really keeping your head into it. Great training and fun too.

I went with the heavier motor because I was replacing an apparently defective motor of a similar weight and wanted to keep the CG about the same. I think the BB's with the KFm2 and KFm3 wings really come alive with a little more motor than the 24 gram motors. I like having more power than I really need available and flying throttled back.

Jack
I wouldn't say I'm necessarily a better pilot - I don't fly very consistent patterns, I pretty much let it go where it wants and generally just noodle about the place. I do like to fly them pretty fast though. Don't forget it's only 3/4" Dihedral per side too - it's a little slower to correct itself, but then it not going to drop a wing as easy when I 'over turn'. This Kfm3 one is only an RE plane too, though it's got me pretty fired up to try flying ailerons.

I decided to build it without landing gear to keep it as clean flying as possible, and it really shows. I also dropped my fuse width down to about 1 1/2 inches, and I think those two changes help the wing achieve what it does without too much struggle.

Just on flying styles too, it's funny how we all like to do it a bit differently. One guy I know just flys the same rectangles every time he goes out, and likes to keep it pretty slow and close to the ground. No loops, stall turns, nothing. It's not very exciting, but it's got a real scale look to it. Quite nice to watch really. He flys the straightest lines and neatest turns you'll see. He could probably fligh circuts of a soccer pitch an even 20 ft. high and directly above the lines the whole way around.

I'm the opposite really - Almost either full speed or super slow on a pass, high, low, here, there, half a turn, upside down, vertical, stall turn, half a low pass, gee I think I'll land, no I won't, glide a bit, Figure eight, nah too hard, just make it a few circles, nah back to stall turns... etc. etc.

My goal is to try to fly with more discipline, and try to stick to a smaller area, and perfect the art of neat consistent circuits. As we all know - that basic stuff is harder than it looks, and so important to get under your belt if you want to progress to more serious aerobatics and or bigger planes
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Old Oct 01, 2008, 05:30 AM
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Australia, QLD
Joined Jul 2008
178 Posts
I maidened mine last weekend, well, actually, I had two other pilots fly it first as I have never flown fixed wing before. Both said it was twitchy. We reduced the control travel and they still found it twitchy. Their recommendation was for me to reconstruct the fuselage and make it a few inches longer. Is this a good idea?
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Old Oct 01, 2008, 06:52 AM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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Twitchness

Quote:
Originally Posted by TongueTied
I maidened mine last weekend, well, actually, I had two other pilots fly it first as I have never flown fixed wing before. Both said it was twitchy. We reduced the control travel and they still found it twitchy. Their recommendation was for me to reconstruct the fuselage and make it a few inches longer. Is this a good idea?
TT,
Welcome to the BB thread. What version of BB did you build?

In general I would say that your bird is probably just a little tail heavy, unless you have a 24"er. They are a might touchey, as with any small model, but if yours is a 33" or larger. It sounds initially like a CG issue.

Certainly adding moment to the fuselage will tame any twitchy habits, but will add to tail heaviness. Check CG first.

Ken
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Old Oct 01, 2008, 07:02 AM
Glue-it-again-Ben!
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Adelaide, Australia
Joined Apr 2008
813 Posts
Quote:
Originally Posted by TongueTied
I maidened mine last weekend, well, actually, I had two other pilots fly it first as I have never flown fixed wing before. Both said it was twitchy. We reduced the control travel and they still found it twitchy. Their recommendation was for me to reconstruct the fuselage and make it a few inches longer. Is this a good idea?
Ken is right - CG is very important. 1/2 inch either side of recommended can make quite a bit of difference.

If it is correct, here are some other ideas...

Have you got a computer radio TT? If so you could limit the travel further (especially rudder), an dial in some expo.

My standard UC BB's have been pretty responsive too - much more so than I would have thought. Don't forget the original design was made to get around in a basketball court. They'll turn pretty hard, especially at speed. Small and gentle movements on the rudder are the way to go.

If your looking to modify the plane itself, I'd look to something simpler than re-making the entire fuselage. How about increasing the size of the rear stabilizer, and decreasing the size of the rudder to the same degree? To do this you could start with the same shape as the original, and just move the hinge point 10mm further rearward.

Really though, it's all about the thumbs. Get it up nice and high so you've got some room for errors, and practice making your turns and corrections with nice small gentle movements. You'd be surprised how quickly you'll get the hang of it.
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Old Oct 01, 2008, 07:09 AM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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Blxpy,

Great comments and advice!

Ken
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