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Old Sep 01, 2010, 09:37 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
North AL, USA
Joined Nov 2009
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Quote:
Originally Posted by jackerbes View Post
With the ease of wing swaps on the BB's I'd encourage anyone who has mastered the RET setup with a wing with dihedral and is interested in trying ailerons and more spirited flying to consider building a flat (no dihedral) KFm3 wing with ailerons on it.
Jack,
I'm not far off being ready to go with ailerons; I know I need to cut the dihedral by 1/2, so my thought is to cut the existing kfm2 wing I have in half and re-join with the reduced dihedral then cut out the ailerons.
Do you have any tips for re-joining the wing? I'm sort of concerned about getting the angle right. It went together real well the first time though...
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Old Sep 01, 2010, 09:45 PM
Jack
USA, ME, Ellsworth
Joined May 2008
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Sand the edges vertical and butt them up and glue them like they were originally. With the tape wrap and all.

But it would be a great chance to build a KFm3 wing with a one piece center panel, a one piece KFm strip, and a one piece full width spar. Without the center joint it would make for one tough wing.

Jack
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Old Sep 01, 2010, 10:18 PM
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Freddie B's Avatar
Omaha Nebraska
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Since the easy way to set dihedral is to lay one wing down flat, raise the other tip while gluing, just use what ever height you like. The Original was 1 1/2' per side (3" for raised tip), if you want 1/2 then go with 1 1/2" raised tip.

If you have aileron experiance, I don't think you need that much with ailerons, so if you go anywhere between 1" and 1 1/2" it should be fine. No aileron experiance keep it at about 1 1/2"

I do KFm2 or KFm3 with two seperate panels and join in the middle, epoxy perferred, some type of center section wood joiner (bass or popcycle stick), but on the 33" version, I don't find a need for a spar. A KFm2, fiber strapping tape will do, KFm3, just foam!

And yes, you can just cut ailerons into the existing wing if you like. I usually never final cut/remove ailerons until I ready to hinge anyway.

So many ways to go, and so many people have built these in so many different ways....Get the hint, what ever works or 'feels right' for you! Hard to get it wrong!

Fred
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Old Sep 02, 2010, 11:27 AM
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I've started getting the bits together to build the 33" version.
I'll be using 6mm depron and was intending to laminate this to produce the monoblock.However I've just found some 1.5" expanded polystyrene so as there are already 1" and 2" monoblock versions I would assume this would be ok as long as I resize the rear bulkhead and top and bottom parts to match?
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Old Sep 02, 2010, 12:11 PM
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Omaha Nebraska
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Originally Posted by ade h View Post
I've started getting the bits together to build the 33" version.
I'll be using 6mm depron and was intending to laminate this to produce the monoblock.However I've just found some 1.5" expanded polystyrene so as there are already 1" and 2" monoblock versions I would assume this would be ok as long as I resize the rear bulkhead and top and bottom parts to match?
Correct! I use 1 1/2", and 2" white expanded polystrene for mine. It actually helps as the fuse is too narrow at 1", and the polystrene I usually find is very light!

I just use a ruler and measure my finished width, draw with a fine point sharpie right on the foam, and custom cut to the sixe I need! Makes it more personal anyway! I really like the looks best in 2", but 1 1/2" looks real good too!
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Old Sep 02, 2010, 12:36 PM
If it flies, I will crash it
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USA, CO, Westminster
Joined Jan 2008
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Not sure if you have caught this earlier in this thread, it has been mentioned many times but laminated mono blocks have shown to be a little stronger then the solid foam block ones. The choice is yours and both will work fine and of coarse the solid one is a little easier to build.

Rob...
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Old Sep 02, 2010, 02:41 PM
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Germany
Joined Jun 2009
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Some weeks ago I posted pics of the blubaby I made for a friend.
He enjoys it a lot but although I have some other planes to show off with I had to give MY BB a new unique touch

Here's what I came up with:
I recently ordered some LiPos from HKs german warehouse and they happened to have these things in stock: http://hobbycity.com/hobbyking/store...dProduct=10793

They were cheap so I thought why not give it a try and turn my BB into a nightflyer.

I just finished embedding around 150 LEDs into the existing plane and I tell you it looks awesome.
Unfortunately it doesnt look that good on the pics, but you'll get a slight idea of what it looks like.

Btw.: Im running my BB on 2s wich makes those LEDs light bright and nice. On 3s its almost blinding. Also the red light is a true red and not the magenta-ish I've seen other super bright LEDs emit.

Can't wait to see the faces at the field when its dawning and I plug in those lights to keep flying some more
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Old Sep 02, 2010, 04:25 PM
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Thanks for the replies Freddie B and mxspode.


Ierwin, the lights look great
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Old Sep 02, 2010, 05:25 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
North AL, USA
Joined Nov 2009
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Quote:
Originally Posted by jackerbes View Post
But it would be a great chance to build a KFm3 wing with a one piece center panel, a one piece KFm strip, and a one piece full width spar. Without the center joint it would make for one tough wing.

Jack
OK, I saw your earlier post about a flat wing panel with no dihedral. I don't have any aileron experience, although I know when and when not to use them, and make very slight movements. Does the flat wing really behave that well on the BB? Does it have a tendency to right itself if you center the stick? I just know on some models with a flat wing you better know what you are doing (of course the BB doesn't behave like an Extra 300)...

I made a kfm3 wing for a OK30 I have with the dihedral per the plans, and even with the glue and taping it is one tough wing! How far out would you recommend the spar? All the way to the tips?

Thanks!
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Old Sep 02, 2010, 06:44 PM
Jack
USA, ME, Ellsworth
Joined May 2008
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I built one KFm3 wing without ailerons and it has sagged over time until it has a scant 3/8" or so on each tip and it flew very well that way.

I had gotten to be a better pilot over time but I know I could still let that thing fly itself to a great extent and that it will self recover from mild turns.

If there is a point where the dihedral might be missed it would be if you let it get close to a stall and got one wing way low. It probably would not recover from that whereas the classic BB's with 2" or so would have a fighting chance at a self recovery.

I also built a SPADET LC-40 (a Coroplat copy of the SIG LT-40 high wing advanced trainer/sports flyer) with a one piece flat wing and had some misgivings about my ability to handle anything that big and heavy (6.5 pounds, 64" wing span). But that turned out to be a very stable flyer also. The amazing part about the SPADET was that with all that weight, it really handled gusts and cross winds well and yet it would seem to want to glide forever.

So I don't want to talk anyone into building something they cannot fly. But I really think when you get to the point where you are starting to feel the desire for a little more performance and maneuverability, maybe even getting a little bored with the RET/dihedral wing, a flat wing on a BB 33 is not going to be a Hyde to Jekyll transition. And as your skills progress you'll probably like it better.

Jack
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Old Sep 02, 2010, 07:14 PM
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Forums are great, as opinions differ. I'll give you mine, but you have to make that final choice. There are no 'right answers', just passing along something I believe in whole heartedly. I have flown hundreds of R/C airplanes, and have trained other to fly too. I wish I had someone back when, because I was self taught, and that made me a good builder.

With little or none aileron experiance, some dihedral recommended. Even basic trainers have some. A flat wing would almost not work on full scale, but then again tapered wings have dihedral 'built-in' with their changing rib thickness. R/C models with our great radios help us out a lot.

Yes, no dihedral is cool, and fun, but with experiance behind you! It's called netural stability! No you do move the ailerons a lot, after you know what you are doing! Bank and crank is the term, and so much fun. Basic, aileron and elevator is similar to rudder and elevator, but much more precise.

Beginners over control, so then have to over control even more, until wham! So a beginner needs smaller travels, and absolutely does a flat wing not correct itself anything like a wing with dihedral does.

I will add this, I have been looking at lots of KFm airfoil data, and although I have not proven this personally, there is info that unlike conventional wings, KFm is more stable without dihedral. Flat plate, say goodbye on self righting stability! Delta wings have tons, but the sweep gives the same affect as dihedral, like in ever 2 to 3 degrees of sweep, same as 1 degree of dihedral.

So the opinion, based on what you stated, no aileron experiance, should you have some, yes. After it is easy enough to make a wing with none, but learn the next step in your skill building first.
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Last edited by Freddie B; Sep 02, 2010 at 07:21 PM.
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Old Sep 02, 2010, 07:40 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
North AL, USA
Joined Nov 2009
1,934 Posts
Type of Material for 12" BB?

We have an indoor fly-in every month in my area and I would like to build a small size BB to fly in the gym; this facility is small and I don't even think it is the length of a basketball court. I'm thinking the 12" BB plans may be a good fit. I flew my OK30 in the gym; fuggetaboutit, all I could do was constant full left rudder and one big circle!

I have some Air Hogs gear I can salvage if the airplane isn't suitable indoors (thrust differential steering). I haven't been happy with the way it performs, but that might be just me and trying it outdoors. I'll be flying indoors in about a week, so we'll see what happens. I really like the way the BB handles, and I think I would be much happier with it than the stock airframe. I'm not all that interested in a traditional servo arrangement because of the size.

I saw an earlier thread for a re-use of Air Hogs gear by yarsmythejr, but wasn't sure what kind of material to use, or how he put it together. yarsmythejr, if you are around could you provide some info on how you put this together? Looks like from your pic you had a solid block for the fuse with just enough cut out for the electronics package. What thickness of material did you use for the wings, stab, and fin?

Thanks.
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Old Sep 02, 2010, 07:45 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
North AL, USA
Joined Nov 2009
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Freddie B, thanks for the feedback. I learned to build with balsa 35 years ago with my dad, who is very precise. That has helped me make sure I have things right when building these. I'll certainly weigh the options...
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Old Sep 02, 2010, 09:33 PM
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Canada, BC, Williams Lake
Joined Jan 2010
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I have a straight wing Kfm 3 4 channel BB33 ( say that fast 5 times ) . The 1 thing i really notice over my 3 channel UC BB33 is that on landing it likes to dip a wing so you really have to watch . My first few flights with it were great but landings were sketchy , Almost snapped the tail clean off on 1 when the LH wing caught and spun it around . I find it also has very little self righting ability , it is fun to fly but you have to be on the sticks alot more then the 3 channel ( no more daydreamin when flying i geuss )
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Old Sep 02, 2010, 11:29 PM
Addicted to building...
Freddie B's Avatar
Omaha Nebraska
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Quote:
Originally Posted by ruff1 View Post
yarsmythejr, if you are around could you provide some info on how you put this together?
Thanks.
Try sending him a PM (private message). If he is still around I'm sure that is a great way to get ahold of him.

Fred
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