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Old Sep 07, 2010, 08:09 PM
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Originally Posted by BEC View Post
One thing I love to do on days when people say it's "too windy to fly" is take a plane up and park it in the sky, or fly backwards (relative to the ground).
I did exactly that last night. Flew pretty much stationary... or just keep climbing up. My favorite plane to do this with is the Nutball.... but that's another thread.
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Old Sep 07, 2010, 08:17 PM
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Wonderful tips, everyone. I've used the "over the shoulder" trick with a newbie and you're absolutely right--it has some magic ability to trick the brain! And I do like the "wing still in one piece" idea for building dihedral. Seems like a more reliable way to get a pretty joint.

You guys have inspired me to make three wings, so we can incoporate some experimental design into the build. One undercambered (no ailerons), one KFm (no ailerons), and one KFm (w/ ailerons). Might as well, eh? For the goals of the club, the building process is just as important as the flying. One further question: would you recommend the KFm airfoil without ailerons, or would another KF airfoil be a better choice?

Awesome help everyone. So pumped to get cutting! And I just found out our school has a laser cutter capable of cutting through sheet metal....I think it should handle Depron just fine
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Old Sep 07, 2010, 09:11 PM
Jack
USA, ME, Ellsworth
Joined May 2008
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"..PS, does th BB fly well when cows are flying over the barn, the train is zooming in the air like a torpedo, and people can fly bikes 200 feet up???..."

The BB with a KFm2 or KFm3 wing will do pretty well in 10-15 MPH wind once you've masterd the basics of RET flying. In fact, it can be a lot of fun. You can do helicopter landings, pick it out of the air by hand, etc.

If you build a heavier BB and over power it a little it can be flown in winds even higher than that. My 24 to 27 ounce "Industrial Strength" BB's were what let me learn to fly in winds that ranged from dead calm to a steady 15-20 MPH and gusting up higher. That was with KFm2 and KFm3 wings (RET only, no ailerons) not a UC wing.

One thing you have to remember about flying on winder days is that it is important to pay attention when you launch. If you do not have enough power to make reasonable progress directly into the wind it is not a good idea to fly.

And if you have enough power to launch but none in reserve (i.e., you have to launch at full throttle to fly into the wind) you are still on shaky ground. Because if the winds are a little higher at altitude and/or if they pick up a little, you run the chance of losing it downwind.

You can fly year around in Maine but a UC winged BB with a Blue Wonder is not the hot ticket for very many of the days. A BB 33 that weights 18 or 20 ounces or even more and that has 100 to 150 watts on tap with a low Kv motor and a big slow fly prop is the hot ticket for the windier days.

Ken mentioned a few posts back that "..the BB is a purpose designed 3 channel RET plane..." and I don't argue with that.

But it was designed by a guy with an open mind, who loved anything that enhanced the RC experience for him, and he soon took it way beyond it's original intended purpose. So all things said, if you want to embellish or change the BB to better suit your conditions or enhance your experience, there are no rules against it.

How many here really know what the design purpose of the Blu Baby 33 was? Not many I'll bet. To quote The Master Himself from post #1 and refresh your memory I'll remind you what he said:

"..It was developed for a specific reason; to provide a platform that my flying buddy, Airplane Ed, and I could actually fly inside an armoury without bringing home a bag of parts after every flying session. You see, we’re not very good pilots and concrete walls, terrazzo floors and steel beam ceilings are murder on our dumb thumbs. Every indoor session was followed by three nights of rebuilding and that was getting pretty thin. As we have a pretty long indoor season up here in Kanuckistan (nine months of winter, three months of road repairs) something clearly had to be done.

Enter the Blu-Baby. She is a 3-channel high wing monoplane of 33.5” span. She sports oversize tail surfaces for exceptional stability, moderate dihedral for tight turning and spiffy looks, a 4-40 undercambered airfoil wing with generous area for slow speed performance and pleasant stall characteristics and a simple taildragger gear with a rear landing skid. The Blu-Baby pioneered a method of construction I refer to as ”monobloc” construction, a technique I now use on many of my planes...."

Thanks again for the Blu Baby, Tony!

Here are some more history lessons. About 9-10 months before he started Blu Baby thread, tony65x55 started messing around with the Kline-Fogelman airfoiled flying wing that eventually came to be called the Zagnutz. That wing was producing some very interesting and positive results and it was only inevitable that the Blu Baby eventually got a Kline-Fogelman wing of it's own.

And Tony, thanks again for bringing the Kline-Fogelman airfoil to electric RC!

And of course, thanks also to Richard Kline for playing with paper airplanes and noticing something interesting in a stepped airfoil!

Jack
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Old Sep 07, 2010, 09:13 PM
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Originally Posted by doughpat View Post
One further question: would you recommend the KFm airfoil without ailerons, or would another KF airfoil be a better choice?
I've flown KFM2 and KFM3 airfoils both with and without ailerons. They work well either way. Just be sure to sure to use the dihedral shown in the 'world' plans... both aileron and non-aileron (RET) versions are shown.
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Old Sep 08, 2010, 01:07 AM
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Originally Posted by philipa_240sx View Post
Just be sure to sure to use the dihedral shown in the 'world' plans... both aileron and non-aileron (RET) versions are shown.
'world' plans? I'm guessing that this is a specific 'view', the one that shows the completed plane from the side (fuselage view), the front, and the top? It shows the CG as 2.3-2.6" back from the LE.

Pumped to start cutting!
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Old Sep 08, 2010, 01:12 AM
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Omaha Nebraska
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Quote:
Originally Posted by doughpat View Post
'world' plans? I'm guessing that this is a specific 'view', the one that shows the completed plane from the side (fuselage view), the front, and the top? It shows the CG as 2.3-2.6" back from the LE.

Pumped to start cutting!
Correct. Howeber the CG is for the KFm airfoil, the undercambered wing is more forward, as shown on that specific wing plan.
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Old Sep 08, 2010, 01:13 AM
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Why are there 32 and 33 inch versions? Seems like an awful small difference to bother with a whole new set of plans...
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Old Sep 08, 2010, 03:47 AM
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Originally Posted by doughpat View Post
Why are there 32 and 33 inch versions? Seems like an awful small difference to bother with a whole new set of plans...
Specific to the undercambered and KFm wing differances, and related wing seat area (shape). With CAD the changes were minimal, I'm sure, and if you print all the parts, you will see most are the same.

I'd venture all the other sized BB's are just 'scaled' up or down in CAD too!

Fred
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Old Sep 08, 2010, 01:40 PM
treefinder
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SE MI
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Actually in Tony's original plans, they aren't just scale up/down. I made a 24" BB by scaling down the 42 inch plans I'd already downloaded, then shortly after Tony posted the "official plans" and I discovered he had increased the tail surfaces a good bit, and made wing chord longer. So I made one to his plans, and as you might expect, his version flew better! (mine was faster stall and more twitchy to fly - probably more control surface movement to get equivalent response) I don't know about the 33 to 42, however, but wouldn't be surprised if there were tweaks from the original at 33 to the larger size as well. All that said, if you just scale up down, it'll still be a good flyer! In my 24" BBs situation, the difference was noticeable, but only when doing an A to B comparision.
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Old Sep 08, 2010, 07:34 PM
A Day @ a Time - Matt. 6:25-34
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North AL, USA
Joined Nov 2009
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I don't know how Tony does it, but the 42 kfm2 RET I built flew great the first time I launched it into the air. You won't be disappointed!

I'll also give credit to many who frequent this thread who helped me avoid some of the pitfalls...

Now, if I can just get some more flying in, it has been a busy summer (unfortunately not at the field!).
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Old Sep 08, 2010, 08:06 PM
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Build begun! Started cutting foam last night. Being my first scratchbuild, it isn't the prettiest pile-o-parts in the world. So I asked another teacher here (a bit of a guru in all things mechanical) and he says "Well why didn't you ask to use my laser cutter?"

Yes, that's right, a laser cutter. Apparently one that can cut through sheet metal (depron shouldn't be a problem ). It has a bit of a small capacity (12" x 18"), so the wing will have to be in two pieces (I like the idea of one!) but the monoblock, hoz/vert. stabilizers, fuse keels, etc. will all fit. The only "but" here is that the cutter uses exclusively Corel Draw (anything below version 11). So here goes: Are there BB plans in Corel Draw?

Also, does regular sand paper to an OK job at smoothing/rounding edges of depron?

Thanks to everyone!

Ryan
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Old Sep 08, 2010, 09:52 PM
treefinder
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The trick to sanding is to make a sanding block or shingle. Jack uses actual cedar shingles split to an inch or so width and glues sandpaper on them for sanding sticks. I have glued emery cloth onto a 2x2 about 15 inches long that makes a nice sanding block. It's especially nice when setting the UC wing dihedral angle when using Ken's (dz1sfb) technique for making wing joints. I also use it like a block plane to round the LE and any other rounded parts of the plane.
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Old Sep 08, 2010, 10:33 PM
Jack
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Here is is in action - The Sanding Shingle

Use open grit woodworking paper, I like 60 grit and 100 grit. That one has been in use for three years and has plenty of time left in it.

This was a KFm4 wing on the Divinity 42, it is five layers of FFF at the centerline (3 wing layers and two more on top at the center).

Jack
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Old Sep 08, 2010, 10:42 PM
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Originally Posted by doughpat View Post
Build begun! Started cutting foam last night. Being my first scratchbuild, it isn't the prettiest pile-o-parts in the world. So I asked another teacher here (a bit of a guru in all things mechanical) and he says "Well why didn't you ask to use my laser cutter?"
The trick to cutting foam is using a very sharp blade. I use single edge razor blades meant for scrapers and #11 hobby knife blades. I have never needed a CNC, laser, etc.
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Old Sep 08, 2010, 11:00 PM
Crash it first, Then fly it
Griffindor's Avatar
The Big Apple
Joined Jul 2008
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Maybe buy a sharpnening stone too. After a couple of cuts, sharpen, and it never gets dull!! Saves you tons of money spent on new blades, and it's cheap at Home Depot or most other hardware stores.
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