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Old Jun 30, 2009, 06:27 PM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
10,541 Posts
Quote:
Originally Posted by airheli1201
hi guys
i just finished building my BB 24 with the following specs

UH 10g 2000kv motor
gws 5030 prop
10a esc
3 hxt500
2s 460mah rhino

plane specs:
"full house"
flat simple wing with no dihedrel
around 150g AUW (with 1/2oz lead up front, too tail heavy!)

had a short madien this evening and after encoutering the following problems i stopped flying.
I notice that when turning, the BB was losing altitude very very fast! which resulted in a few crashes, also the plane requires some speed to fly otherwise it would fall out of the sky. I wonder if these 2 problems is as a result of me choosing the flat simple airfoil for the main wing??

can anyone give me some advise on how to make this fly better?
maybe if i put on a kfm2 wing it would make the whole plane fly slower and better at turnings?
I agree with Rbrown3rd, go with the undercamber wing. I have flown the 24 with ailerons (KFm3) and without (UC). Much more fun to fly with the UC wing. The geometry of the 24 just does not lend itself well to ailerons.

Ken
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Old Jun 30, 2009, 06:35 PM
Addicted to flight since 1944
rbrown3rd's Avatar
southern Florida
Joined Feb 2004
1,750 Posts
Quote:
Originally Posted by Wuwu
First video.

BBAP2 - Blu Baby Aerial Photography mk 2 (7 min 21 sec)

Wuwu
Nice. Looks like you got up to 1,000 feet or more. Loved the birds passing by in the early part of the video. There was something streaming by the camera at about the six minute point. Looked like water or something. You have a bit of vibration too. Prop out of balance? I notice that a lot of the AP'ers shut the motor off completely when shooting stills. When you throttled back for landing the video got sharper so I think the vibration was blurring it a bit. Thanks for taking us along on your flight. I really enjoyed it.
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Old Jun 30, 2009, 06:51 PM
Registered User
United Kingdom, England, Milton Keynes
Joined May 2007
596 Posts
thanks dz1sfb and rbrown3rd. for replying so quick
i will build the UC wing tomorrow.
I had a look at the video on how to roll the wing. thanks for that it looks very easy! I may have to apply some heat in order to roll depron but it's no big deal.
will post flight report with UC wing.

oh btw how many inch of dihedral is needed?

there sure are many helpful people here.
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Old Jun 30, 2009, 07:50 PM
AKA Don
bz1mcr's Avatar
United States, MI, Houghton Lake
Joined Dec 2002
7,608 Posts
Quote:
Originally Posted by airheli1201
hi guys
i just finished building my BB 24 with the following specs

UH 10g 2000kv motor
gws 5030 prop
10a esc
3 hxt500
2s 460mah rhino

plane specs:
"full house"
flat simple wing with no dihedrel
around 150g AUW (with 1/2oz lead up front, too tail heavy!)

had a short madien this evening and after encoutering the following problems i stopped flying.
I notice that when turning, the BB was losing altitude very very fast! which resulted in a few crashes, also the plane requires some speed to fly otherwise it would fall out of the sky. I wonder if these 2 problems is as a result of me choosing the flat simple airfoil for the main wing??

can anyone give me some advise on how to make this fly better?
maybe if i put on a kfm2 wing it would make the whole plane fly slower and better at turnings?
I think you need more power.

I have two BB24's. One at about your weight (mine uses 2 servos and 760 mAh 2S battery). It also has a 2100 Kv motor (23g) and a 6-3 GWS prop. I have flown it with a 7X3.5. It a great flyer with a 24" UC wing (about 1" total dihedral).

The other uses a 10g 2100 Kv motor and batteries from 250-460 mAh using a 26" UC wing with about 2" total dihedral. At 80g it is almost half the weight of the larger one. It has never been a good flyer even after I carved out a new battery bay in front of the gear location to move the CG forward. I have played around with CG, wing incidence, motor thrust line and props. It flies best with a GWS 6-3. I have yet to find a combination I really like. I am thinking the 2.5g servo I used aer not centering well. You just need to be on the sticks all the time.

With any of the KF wings you need to fly a lot faster. That means more power. You could try 3S, or get a motor with higher Kv and use a larger prop. Perhaps a 7-6.


Don
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Old Jun 30, 2009, 08:52 PM
Fred
warydragon's Avatar
Concord, North Carolina, USA
Joined Jun 2009
55 Posts
Quote:
Originally Posted by warydragon
Since my childhood, one of my "Bucket List" items is to fly RC. A couple of weeks ago I started spending time with FMS simulator and bought an Easy Star and started reading this newsgroup. Now, I can land somewhere near the landing strip on FMS and I have read about 1/3 of this newsgroup and I have about an hour of flight time on my AS. Thank you Tony and others for providing the incentive and information.

Today I completed my Blu-Baby33 using the Dow blue fanfold foam. Thank you Tony for your contribution to RC aviation. Your BB has also piqued the interest of my old U-control flying buddy. We last flew U-control in the mid 70's.

My Blue-Baby has a few small changes. I extended the angle of the outer portion of the wings back to the fuselage. The chord of mine UC wing measures from about 9" to 7".Skewers are bent at leading and trailing edge of wing. The fuselage was adapted to accept this wing. The front of UC wing is taped with 2" extreme 3M packing tape. I will hand launch for now so I haven't provided for landing gear. My fuselage is 2" overall width and about 1/2" shorter. I raised the stabilizer 1/2" which took some area from the bottom of the rudder. I made the back of the rudder proportionally larger.

Motor: 2712-12 Outrunner Brushless Electric Motor from HeadsupRC.com, 1200KV, 0.9oz
Mount: Aluminum firewall motor mount
Prop: GWS EP 8040, 8 ounces thrust at 3.5 amps with a pitch speed of 26 mph on 2 cell LiPo.
Prop Saver: Prop Saver for 3mm Shaft - with Rubber 'O' Rings ID 0.56"x0.06"
ESP: Power Up, 10 Amp, 0.3oz allows up to 4 servos.
Battery: Lipo 7.4v 500 mah 20C - 10 amp Lithium Polymer
Servo: Tower Pro SG90 9 gram Sub Micro Servo, 0.37oz, universal "S" type connector
Receiver: Futaba R617FS 7-Channel 2.4GHz FASST Receiver, 0.25oz
flying weight: 7.5 oz

I am securing the 500 mah battery to the top of the fuselage behind the motor. I plan to use a 1200 mah later in the battery bay.

I used Gorilla white Polyurethane [PU] glue for almost everything and hot glue to secure the servos and push rod tubes. I have an aesthetic problem with the excess foaming of the PU glue at the joints. What glue is used to fillet the joints?

I hope to glide test my BB33 ASAP.

Fred
Concord, NC, USA

Thanks for the glue advice. I'll try all these techniques the next time. This is an impressive group.

My maiden flight this afternoon with my BB33 lasted over 11 minutes with the 500 mah battery. I had a little wind so I had to really fly it most of the time. It was easy to land. I would slow it down to a stall a few inches off the pasture and it would just gently plop into the 6" grass. I landed it 6 times and didn't even knock the prop off. This a cool airplane. The little motor sort of buzzes like a big bee. Actually I expected it to be more quiet. I see why everyone loves to the Blu-Baby33 so much.

In flying it I did noticed several irregular behaviors:
1. I had to dial in a lot of up elevator when trimmed for level flight at slow cruising speed.
2. At this trim, when I chopped the throttle for a glide I had to give more up to keep a good glide path.
3. And, anytime with some acceleration I would have to give down to prevent a stall condition. It would really try and climb.

This might be the solution; upon rechecking the CG, it was 2" from the leading edge. I think I need to move it back to 2.6", or more, since my wing is a little wider than Tony's plan.

Another thing is I have "0" incidence on the UC wing in relation to the angle of the stabilizer. Meaning the bottom of the leading edge and training edge of the wing form a line parallel to the stabilizer. Maybe I need to shim the front of the wing up a 1/4" or so like someone has suggested. Although, I don't understand this.

My motor is angled down about 3 degrees.

My rudder was right on from the start. I had put my push rods in the 3rd servo hole from the end and the control horns in the outside hole for about a 1/2 ratio. This was plenty of control for both the rudder and elevator.

Thanks for the help.

Fred
Concord, NC, USA
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Old Jun 30, 2009, 09:42 PM
BANDITRCN28
cvoyles's Avatar
USA, NC, Salisbury
Joined Jan 2008
808 Posts
Quote:
Originally Posted by warydragon
Thanks for the glue advice. I'll try all these techniques the next time. This is an impressive group.

My maiden flight this afternoon with my BB33 lasted over 11 minutes with the 500 mah battery. I had a little wind so I had to really fly it most of the time. It was easy to land. I would slow it down to a stall a few inches off the pasture and it would just gently plop into the 6" grass. I landed it 6 times and didn't even knock the prop off. This a cool airplane. The little motor sort of buzzes like a big bee. Actually I expected it to be more quiet. I see why everyone loves to the Blu-Baby33 so much.

In flying it I did noticed several irregular behaviors:
1. I had to dial in a lot of up elevator when trimmed for level flight at slow cruising speed.
2. At this trim, when I chopped the throttle for a glide I had to give more up to keep a good glide path.
3. And, anytime with some acceleration I would have to give down to prevent a stall condition. It would really try and climb.

This might be the solution; upon rechecking the CG, it was 2" from the leading edge. I think I need to move it back to 2.6", or more, since my wing is a little wider than Tony's plan.

Another thing is I have "0" incidence on the UC wing in relation to the angle of the stabilizer. Meaning the bottom of the leading edge and training edge of the wing form a line parallel to the stabilizer. Maybe I need to shim the front of the wing up a 1/4" or so like someone has suggested. Although, I don't understand this.

My motor is angled down about 3 degrees.

My rudder was right on from the start. I had put my push rods in the 3rd servo hole from the end and the control horns in the outside hole for about a 1/2 ratio. This was plenty of control for both the rudder and elevator.

Thanks for the help.

Fred
Concord, NC, USA
I think your on the right track Fred, with the wing incidence and shimming it up. Also it sounds like it is a little nose heavy and if you move the CG back I would try 2.5in back or a little less...

Chris...
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Old Jul 01, 2009, 02:18 AM
wave-off
Wuwu's Avatar
Polska, Śląskie, Świętochłowice
Joined Aug 2006
139 Posts
vibration

Quote:
Originally Posted by rbrown3rd
Nice. Looks like you got up to 1,000 feet or more. Loved the birds passing by in the early part of the video. There was something streaming by the camera at about the six minute point. Looked like water or something. You have a bit of vibration too. Prop out of balance? I notice that a lot of the AP'ers shut the motor off completely when shooting stills. When you throttled back for landing the video got sharper so I think the vibration was blurring it a bit. Thanks for taking us along on your flight. I really enjoyed it.
Thanks. I changed prop saver to prop adapter (colet type).
I'm glad You enjoyed it.
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Last edited by Wuwu; Jul 01, 2009 at 02:50 AM.
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Old Jul 01, 2009, 08:35 AM
AKA Don
bz1mcr's Avatar
United States, MI, Houghton Lake
Joined Dec 2002
7,608 Posts
The need to adjust elevator when speed changes seems to be a characteristic of UC wings. I think you will find increasing wing incidence makes it worse. A shim under the back of the wing might help, but the fundamental characteristic will still be there,
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Old Jul 01, 2009, 09:40 AM
wave-off
Wuwu's Avatar
Polska, Śląskie, Świętochłowice
Joined Aug 2006
139 Posts
dihedral

Quote:
Originally Posted by airheli1201
thanks dz1sfb and rbrown3rd. for replying so quick
i will build the UC wing tomorrow.
I had a look at the video on how to roll the wing. thanks for that it looks very easy! I may have to apply some heat in order to roll depron but it's no big deal.
will post flight report with UC wing.


oh btw how many inch of dihedral is needed?

there sure are many helpful people here.
1 inch
If you have aileron, dihedral is not needed.
Otherwise is mandatory.
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Old Jul 01, 2009, 10:42 AM
Postcards From The Purple Edge
tuppertn's Avatar
United States, OK, Sand Springs
Joined May 2007
3,919 Posts
Quote:
Originally Posted by warydragon
In flying it I did noticed several irregular behaviors:
1. I had to dial in a lot of up elevator when trimmed for level flight at slow cruising speed.
2. At this trim, when I chopped the throttle for a glide I had to give more up to keep a good glide path.
3. And, anytime with some acceleration I would have to give down to prevent a stall condition. It would really try and climb.

This might be the solution; upon rechecking the CG...

Another thing is I have "0" incidence on the UC wing in relation to the angle of the stabilizer.
The plans call for 2 degrees of positive incidence for the UC wing. UC wings, like most "flat bottom" airfoils, need to fly with some positive incidence. If it's not built into the wing saddle then, as you've already seen, it has to be compensated for with up elevator trim. Same effect--just coming from a different location.

The CG is probably contributing too as cvoyles already said, so it sounds like you've got two things working against a good trim configuration. I would fix the wing incidence first then work with the CG.

kendall
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Old Jul 01, 2009, 03:17 PM
where did my wings go?
estlin76's Avatar
livingston, tx
Joined Jun 2009
103 Posts
Hello everyone, well i finally joined the forum after spending some time reading the posts and figuring that for a new flyer (well crasher) there is a lot of knowledge here. My first plane was a j3 piper i built from scotta's design. I came across the plans for this Blue Baby and had to try it. thanks Tony for the great plans! I am at the point of powering it and was hoping yall could gimme a lil info. . do i need downthrust and right thrust as i learned this seems to be required to fly. I am using a turnigy bl2210/30 brushless with a 20 amp esc and a lipo 11.1v 1500 mah battery, will this fly it apart like it did my j3?? or should i be ok. Also how much movement should i have on my control surfaces ( just using rudder and elevators.) I want a good maiden and hopfully a good plane to learn to fly on.
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Old Jul 01, 2009, 04:07 PM
Registered User
Xanadu's Avatar
Canada, MB, Winnipeg
Joined Nov 2006
1,584 Posts
Wow.........my new 3s1500ma lipo's came in today, and I tried them on my 32" BB.

Straight vertical, unlimited!... ......LOL..........Hauls that BB around in 15 mph winds, (25km) with no effort at all.
The KMF5 wing handles it extremely well, with no flexing, floats nice, and best all of is strong enough to cut the wind like crazy.

Tony.......you have to build a KMF5 wing and try it!
Put it through the paces so you can give your review.
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Last edited by Xanadu; Jul 01, 2009 at 04:20 PM.
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Old Jul 01, 2009, 04:17 PM
Registered User
Xanadu's Avatar
Canada, MB, Winnipeg
Joined Nov 2006
1,584 Posts
Quote:
Originally Posted by estlin76
Hello everyone, well i finally joined the forum after spending some time reading the posts and figuring that for a new flyer (well crasher) there is a lot of knowledge here. My first plane was a j3 piper i built from scotta's design. I came across the plans for this Blue Baby and had to try it. thanks Tony for the great plans! I am at the point of powering it and was hoping yall could gimme a lil info. . do i need downthrust and right thrust as i learned this seems to be required to fly. I am using a turnigy bl2210/30 brushless with a 20 amp esc and a lipo 11.1v 1500 mah battery, will this fly it apart like it did my j3?? or should i be ok. Also how much movement should i have on my control surfaces ( just using rudder and elevators.) I want a good maiden and hopfully a good plane to learn to fly on.
Nice looking BB, very well done. The only thing you might have a problem with at one point, is the wings flexing back if you get too carried away with the power and hard maneuvers. By adding a KMF strip to it, you will greatly increase the strength. I use the same wing as you, but add a KMF strip to the top leading edge, making it into a KMF5 variation.
That motor and lipo will give it big power, more than enough to bend the wings back if too much throttle is used, and a hard maneuver performed.
When I started doing loops with my first BB, I used to see the wings flap back like dog's ears when they run.

Yes, you do need tad of down thrust, and right thrust to counteract the prop torque, etc. About 3* for either one a good start.
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Old Jul 01, 2009, 04:37 PM
where did my wings go?
estlin76's Avatar
livingston, tx
Joined Jun 2009
103 Posts
Thanks Xanadu, thats what happened to my j3, switch to this power setup and was bout half way thru a turn and off came the wings, talk about feeling helpless! i did reinforce the uc wing but am going to do it like yours also. Do the ribs help as well? this is all new to me and certainly appreciate the advise.
Shawn.
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Old Jul 01, 2009, 04:47 PM
Registered User
Xanadu's Avatar
Canada, MB, Winnipeg
Joined Nov 2006
1,584 Posts
Quote:
Originally Posted by estlin76
Thanks Xanadu, thats what happened to my j3, switch to this power setup and was bout half way thru a turn and off came the wings, talk about feeling helpless! i did reinforce the uc wing but am going to do it like yours also. Do the ribs help as well? this is all new to me and certainly appreciate the advise.
Shawn.
Yes, the ribs help immensly in keeping the airfoil consistent thru the entire wingspan.
I have a total of 3 per side. One at the tip, one in the center, and one along the edge where the wing straddles the fuse.
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