** Blu-Baby Primary Trainer ** Plans, Pics and Fun! - Page 996 - RC Groups
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Aug 12, 2010, 08:27 AM
Registered User
Originally Posted by insomaniac45
hey guys,
i have a question.

heres my problem,
my bb flies ok, but it is really sluggish, and i can only really keep it in the air with approx 75% throttle, anything less and it struggles to climb.

i am using: -
8x4.5 prop
850mah 15c 2s lipo
2829-10 brushless outrunner

bat i know is low, but its all i have atm

it is currently 52"
would it be better if i cut it down to 42"

also my horizontal stab is floppy, would reinforcing it with cf tube be a good idea?

i reinforce my vert stab with a coffee stirrer from mc donalds but i have ran out of them. i have loads of cf tube from kites,

cheers guys

You need to know how much power you are putting out. You need a watt meter, or a volt/ohm/amp meter + math. Otherwise, you are still just taking educated guesses about how much power you are producing. It would be better still to figure out how much actual thrust you are producing.

I reinforced both elevator and rudder.
Last edited by rdhood; Aug 12, 2010 at 10:52 AM.
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Aug 12, 2010, 08:44 AM
Not always grumpy!!
insomaniac45's Avatar
cheers guys,
springer that is my exact motor i will (fingers crossed) be getting some new batteries next week,

i will prob try making a new wing for the moment, (a 42") as the fuse is the ap1, (i thought the wings were interchangable with the fuse)

cheers guys, your help is much apprechiated
Aug 12, 2010, 01:28 PM
springer's Avatar
Just looking at the plans for the ap1, I think Tony scaled it up to the 52" wing, so fuse will be big for a 42" wing. Best to build a new wing, as you will probably want to reuse the 52 when you get the new packs.
Aug 12, 2010, 03:23 PM
Not always grumpy!!
insomaniac45's Avatar
i had another flight today,
(unchanged from previous post) plently of gently elevetor to get me to altitude,

i was circleing the bottom of my field, a little like a glider catching a thermal

and something caught my eye, right behind my BB. about 15ft behind. following me.

an adult redkite what a sight. where is the bloody camera when you need one.

for those who dont know. a red kite, is an endangered bird of prey here in england. their numbers are on the increase. but it is a rare sight to see one. (i have seen this red kite many times before (its nest is near my stables some where)

so next time you might just see a bird as big as my plane, following my plane

oh what fun that was. i really cannot stop smiling. being followed by such a beautiful bird of prey, fantastic

also you know when you have really had a great flight, when you come back to your hanger, when all your batteries are dead. and the plane is undamaged
Aug 12, 2010, 03:37 PM
springer's Avatar
Congratulations on a successful flight and luring a real bird out! Ain't it great to be up there with them?
Aug 12, 2010, 04:26 PM
Went to mow a meadow
frank48's Avatar
Congrats on your flight & seeing the red kite. We have one pair nesting up here in the NE. There are quite a few around Henley on Thames, they fly up and down the river, its quite a sight

Aug 12, 2010, 04:41 PM
Not always grumpy!!
insomaniac45's Avatar
cheers guys,

well if he is interested in my plane again i might just get some really good pics

i guess his wing span must be about 1-1.5m. absolutly beautiful bird, (all in all i have seen 3 together. i have learnt there is a nest behind where i fly, so you never know )
Aug 13, 2010, 09:53 AM
Registered User
Dick, Johns Pop, Springer , et al,
Thanks so much for the "heads up" and the research on the spackle !
So... use the newer stuff...don't use too much...(so you don't have to sand too much)...
and use it and let it dry in a well ventilated or open area...
...and if you are not using an applicating device (spatula , popcycle stick, table knife etc.)
but using your fingers....wear rubber gloves!....right?
Very good to know
Thanks again
Aug 13, 2010, 10:37 AM
Registered User
My second Piper, now in white colour.
Built as crash kit for my previously made J3 Cub .
You are welcome to suggest some colour scheme for this babe.

Aug 14, 2010, 02:52 AM
Registered User
I'm thinking of building the 48" BluBaby with the stock dihedral wing and possibly making the aileron wing later. We'll see. I figure the 48 incher is the largest I can build with a Blue Wonder. I think it'll have enough oomph for lazy flying, but I'm worried it won't be powerful enough for an aileron wing for minor aerobatics like loops, stall turns, or inverted. What do you guys think? Maybe a 36 incher is more in order.

I think most of you guys know me by now, I'm not a newb or anything, lol. But I'm looking for a break from ego/adrenaline driven models. I hope I won't get too board with this plane. After all, I have been cruising my Dart around at 1/4 throttle for multiple packs in a row the last couple days. It's actually been kind of relaxing.

I might build the BluBaby, I'm not committed yet though. Just want to do another quick scan of the plans thread to see if there's some other choices to consider.

- Jeff
Aug 14, 2010, 09:18 AM
Registered User
philipa_240sx's Avatar
Originally Posted by jkarnacki
I figure the 48 incher is the largest I can build with a Blue Wonder.
You can use the simple w/lb rule to determine if you have enough motor:

50 watts/lb: Minimum required for flight.

70-90 watts/lb: Trainer and slow flying aerobatic models.

90-110 watts/lb: Sport aerobatic and fast flying scale models.

110-130 watts/lb: advanced aerobatic and high speed models

I typically shoot for 80-100w/lb on most of my planes. I hate being short on power!

The BW maxes out around 85 watts on a 3S lipo and GWS 9x5HD (straight blade) prop.

IMHO, this is sufficient for up to a 16oz AUW plane with decent performance including a 4ch aileron version. Just to give you and idea, my last 4ch BB42 build came in around 16oz.

If you build light and very carefully, you might be able to keep a 48" WS BB under 20oz. But I'm not sure If I would try a 4ch setup with such little power.

Personally I would just build the BB42 3ch RET to start with. If your build comes in light (16oz or less), then it would be a fine platform for a 4ch aileron version.
Aug 14, 2010, 09:55 AM
jackerbes's Avatar
Not to argue the point but just to share my experiences, I've found a flat KFm2 or KFm3 wing with ailerons to be something that is relatively easy to fly once you have mastered the BB's with dihedral and RET systems.

The high wing generates pretty good stability, even when it does not have dihedral. I think there is a slight "pendulum effect" in high wing planes that makes them want to return to level flight by themselves.

On one of my BB's and later on the high winged SPADET I built I found that if I started a turn with the ailerons and then let the stick center itself, the plane would slowly return to level flight by itself. This was with the plane trimmed out and and balanced for level flight of course.

If you wanted to return to level flight more quickly you could apply aileron that countered the turn of course. But there was not really any amount of inherent instability nor any need to "fly the plane full time" when I went with a flat wing with ailerons from a dihedral wing. And in most cases, the ailerons were much more effective without dihedral than with it.

Once you get past the RET phase and fly with ailerons for a while, you are also probably making a lot of small and subtle control inputs that you are not really even conscious of.

And if you want to be able to keep the wings level in turns because you are shooting videos, the flat wing will really help with that. By using the rudder to make slightly "skidding" turns and applying a little countering aileron I could make perfectly flat turns, especially with the SPADET.

Some fliers are not the least bit interested in using the rudder with ailerons and making coordinated turns but I love flying like that. It has given me the control instincts that give me much better control of the plane on cross wind approaches and things like that.

It will probably start an argument but I think someone that flies "yank and bank" on ailerons all the time is not really a complete pilot. When I hear people brag that "..I never use the rudder..." I don't think "skilled pilot", I think "not fully trained pilot" or "pilot that is not using all his tools."

Aug 14, 2010, 11:17 AM
Registered User
JohnsPop's Avatar
Eeeeasy Jack, eeeasy..... I haven't had time to build much of anything here lately, but I'm looking forward to building a flat KFm wing to get more practice flying just like you're talking about. My BB42 with KFC wing still flies pretty good although a bit chewed up, so I think I'm going to build a whole new 42 with a KFm wing.
Aug 14, 2010, 01:01 PM
Registered User
philipa_240sx's Avatar
Admittedly my 4ch experience is limited to my BB33. So far it's mainly aileron only turns, I've just barely begun to perform coordinated turns with rudder.
Aug 14, 2010, 02:57 PM
Registered User
Thanks, philipa.

I'll take your advice and go with a 42" RET to start.

Now to decide between an undercamber wing or KFm2.....Might have to try the undercamber wing as I've never made one before and I've recently acquired a heat gun. Woohoo!

- Jeff

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