** Blu-Baby Primary Trainer ** Plans, Pics and Fun! - Page 63 - RC Groups
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Aug 18, 2007, 02:14 AM
Registered User
I have been having a problem with my battery packs over heating on this plane due to a lack of air flow, and I think my motor starting to over amp, but none the less I wanted to correct it.

Here is my 'quick fix' for air flow into the battery bay. Sorry for the poor picture quality, I am using a ghetto digi cam.

I am in the process of getting the plane ready to paint after hours of flight time. I finally decided I should paint it when someone asked "What made you paint it pink and blue?" to which I had to explain that was the default color of the foam.
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Aug 18, 2007, 03:46 AM
Registered Aircraft Offender
Truglodite's Avatar
i never had that problem with my original bb. then again, it never had a battery hatch. i admit, your table tennis ball idea looks better.

when ppl ask me why it's blue i tell them it's a spy plane & sky blue is harder to spot. j/k nobody has even asked me about colors or materials yet; they just ask "what's the wingspan?".

please post pics when you're done painting. i'd like to see it.
Aug 18, 2007, 09:11 AM
Micro Flyer "Q"
qban_flyer's Avatar
Originally Posted by warhead_71
I took the plans for the 33" BB and enlarged them to 48" - the exact width of a piece of FFF. It has KFm airfoil and I "slightly" modified the nose to accept my cowl, which is simply a plastic 1-quart oil bottle (2-3/8"x4" cross-section) - which leaves the perfect sized hole for a BP-21 when the neck is sliced-off. I'm using polystyrene for the monobloc and capping the ends with FFF. My KFm wing has about 1/2" dihedral and will have ailerons, perhaps flaperons just for kicks. Also, the KFm wing has a 1/2" step at the wing-tips and tapers to 3/4" in the center (total height, including the FFF). I won't be using that heavy LG and huge wheels, just balanced the plane on them to see how it'll look.
Gotta love that cowl, gotta love it!
Aug 19, 2007, 04:00 PM
Registered Aircraft Offender
Truglodite's Avatar
hehe, i totally love that cowl. when i saw that i was imagining what it would look like using mobil 1 gear oil bottles (the tall skinny kind with the handle).

btw warhead, i like your idea of capping the mono block with fff. i also used eps for the block on my 60" (home depot 2" white foam w/ the plastic skin peeled off). it's nice that it is less "pink". the capped block looks better & probably makes it much stronger regardless if it's pink or white.

Aug 19, 2007, 07:48 PM
Out the Window
High Flyin''s Avatar
I am thinking of building a Blue Baby with a KFm wing for my second plane. I had great luck with a STC with a blue wonder motor, but would like to try something different and maybe larger. I have one of these UH motors: https://www.unitedhobbies.com/UNITED...idProduct=4706

How large of a Blue Baby should I shoot for? I kind of like the idea of putting some wood spars in the wings for strength. Also the built up front end might help me as I was always breaking the front end off of the STC...not a fault of the airplane but bad pilot errors.

Any help would be appreciated!
Aug 20, 2007, 05:35 AM
Went to mow a meadow
frank48's Avatar

Check out post #439 by Kaos2, he's built a 40" with exactly the same motor. It flies great you can see his video on post 440

Aug 20, 2007, 09:59 AM
Always Ready!
warhead_71's Avatar
Yeah - the motor-oil 1-qt bottle makes a great cowl. Best thing is, every time i change the oil I get to make 5 more cowls. Like I said, I had to cut down the nose of the fuse "slightly" to make it fit... keeping the same thrust line and be careful that the motor lines up with the hole for the cut off neck. I originally thought I'd use the same bottle for a cowl for my 40" Tiger Moth that I'm building -- and it's a very, very close fit -- but I decided to make something more scale for that.
Aug 21, 2007, 12:46 PM
Registered Aircraft Offender
Truglodite's Avatar
ray, 33" is a bit too small for for that motor (blue wonders turn a 33" into a hotrod trainer, more than that & you should start looking at faster designs meant for higher wingloadings). 52/60" would be on the floaty side with that motor. so i agree with frank: a 40" kfm with ailerons & that motor would make a great second plane. should be fun to fly when learning basic aerobatics like loops, rolls, inverted..., but it will still be cake to land in one piece.

Aug 21, 2007, 01:24 PM
Micro Flyer "Q"
qban_flyer's Avatar
YEP, elight50 has a BP-21 on his on two cells, spinning a GWS 10" prop. It will loop right out of your hands on hand launch if throttled higher than 1/2 open. Those motors are better used with the larger versions of the BB.

I will be using an E-Flite Park 300 on mine. It should be just about the right motor for it.

P.S. BP hobbies has that same motor for $12.50 and the ESC for an additional $16.95 which is a bit more than what you would pay from UH, but you would get it quicker and being a US purchase I would consider a bit safer.

They have one of their "own brand" BP outrunners that looks quite a bit like the Park 300 selling $17.95 (first link below). Second link leads to a Blue Arrow 10A ESC for $20 from them too. It should be just fine for the smaller BB .


Aug 21, 2007, 07:00 PM
Registered User

Link Request

I can't seem to find the 42'' BB with the KFM wing marked on the drawings. Assistance appreciated.

Aug 21, 2007, 08:18 PM
horton's Avatar

I think Tony is working on the plans. He mentioned he'll have them up within a week.

I'm looking forward to them.

Aug 21, 2007, 09:38 PM
Registered Aircraft Offender
Truglodite's Avatar
elight50, i'm not sure if the 42" kfm wing tony will post is the same, but i know kaos' 42" kfm flies great. if building the wing is holding you back from flying you could use some info from his posts to improvise one.

kaos cut the standard 42" wing then taped a 5" wide fff kfm strip to the LE (post 531). he also claims the optimal step thickness is between 7-9% of the chord (post 528). this equates to using a ~1/2" spar/filler under rear of the strip.

hope this helps.

[edit: btw, kaos used 2" wide ailerons if you're curious.]
Aug 21, 2007, 10:29 PM
Registered User
Originally Posted by horton

I think Tony is working on the plans. He mentioned he'll have them up within a week.

I'm looking forward to them.


Tony, I hope you will publish the full-size plans also (like you did before), instead of just the tiled ones like some others do.

Tony, thanks for a great design, and for sharing.

Aug 21, 2007, 10:35 PM
John 3:16
Daddy-O's Avatar
I am going to start building a Blu-baby with my 11 year old son this week. He has been asking me to teach him how to build planes, and he wants an easy flying plane. I figured this would be the perfect plane. We have already built a STC with an epp fuse that I have since attached lights to, and fly at night. I think this will be a great plane for him and I to do together. We are going to start on Thursday after school, and work on it each night until it's finished. I am going to let him do most of the cutting and gluing, so I don't know how it will turn out. It should be interesting. He will have to learn to be careful with the sharp blades we use, and be sure not to glue his fingers together. Should be fun!
Aug 21, 2007, 10:36 PM
Registered User

33" KFm with Ailerons Build

I'm almost done with my 4-channel 33" BlueCor KFm build. As planned, I used dual HS-55 servos for the ailerons with radio mixing for flaperons and differential compensation. Ailerons are 2" at the root and 1.5" at the tip. Actually, I did not span them quite to the wingtips because I plan to experiment with different tip configurations and want a full cord fixed structure at the tips.

The only thing I'm a little puzzled about is the very narrow elevator cord. The horizontal stabilizer seems adequate, but I wonder about the authority of the elevator. Oh well, nobody else seems to have reported any problems with it, so I'll assume it's all right.

AUW is right on target at just under 9 oz. with AXI 2204/54 motor and 400 maH 2S. I hope to maiden Thursday or Friday.


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