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Old Aug 27, 2008, 06:50 PM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Quote:
Originally Posted by MadDuc
Hi Steve,

Really like the idea of the sliding panel (but adds a bit of weight as well?), I may do something like that as well.

If you're worried about your landings, are you sure you want to land on water? Sure you may have enough space on water, but not sticking it perfectly may cause the plane to crash on the water with the possibility that all your electronics die

Not sure what kind of radio gear you have, but if you can mix you may think of using flaps, you will need 2 servo's for the ailerons in that case (possibly lighter than your floats), but that will help in slowing down the plane for your landings.

Edit: looking at your pictures in enlarged version, I see that there is probably no real extra weight with that sliding door! Clever design!
The panel doesn't add weight it's self but I'll have to add a way to secure it. Probably rubber bands. I think the panel is a good feature. I have the gear layout figured out and I have a ton of room to move the battery for balancing. I'll upload a picture or two.

Servos are just in front of the tailplane on the top. The whole thing right now without linkages is weighing in at 265 grams. (9.35 oz) I project about 3 ounces for the wing, maybe 4. I'd like to keep it down to 5 oz per sq foot. I want enough weight for a bit of wind penetration but don't want to use more than half throttle for slow cruising around. Floats will add a bunch of weight too.

We'll see how it goes.

From your comment, Tony, I should be OK with the bp21 motor. I have a 10 x 4.7 on it now and I have 8 x 4 and 8 x 6 props coming in the order from Hobbycity. I think of 16 oz as absolute max all up wt.

Edit: I can't add flaps coz the radio is only 4 channel. First it'll be rudder steering then I'll add ailerons later. If I like getting back into the hobby I may spend a bit more for a 6 channel and go AP with flaps as you suggest.
Steve.
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Old Aug 27, 2008, 08:00 PM
Jack
USA, ME, Ellsworth
Joined May 2008
16,642 Posts
BB 33 Industrial Strength

The build continues.

I made a centerbloc to replace the bulkhead, provide a wing support, and serve as a center point for the CF arrow shaft to be glued to that will stiffen the fuselage.

Ran the CF arrow shaft 2" into the monobloc. It passes through the tail platform/minibloc and the midbloc/wing support and is glued to each bloc with GG PU. Two hours later and, WOW! Is this thing stiff! There is no perceptible flex or twist in it. I'm not sure when and if I'll ever break this one but it will be interesting to see where it fails. The fuselage weighed 67 grams at this point.

I did some testing and decided that covering surfaces with Uline color tape and then hot gluing them together produces joints that are strong enough to use for the tail mounting. I was unable to get a test glued tail mockup apart without destroying the foam so instead of building and then taping, I am taping the fuselage before mounting the tail assembly with hot glue (regular temperature, slow setting type).

Got the fuselage partially covered, motor mounted, and am ready to start working out the battery location and getting the CG right.

Jack
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Old Aug 27, 2008, 08:15 PM
Jack
USA, ME, Ellsworth
Joined May 2008
16,642 Posts
Tony wrote:

"..Good looking build Jack, watch the weight in the tail!..."

Thank you, Sir.

I think I'm okay there. I checked it today it looks to be OK. I made a CG checker with a scrap of 1 x 6, two pieces of 1/4" dowel, two rubber dental pick tips, and some heat shrink. That will the the Genius CG Checker in the photo below.

With a small screwdriver and a stick of hot melt glue simulating the weight of the two servos that will go in the aft electronics bay, I was right on the money at 2-7/8" back from the leading edge.

I'll go ahead and get the servos mounted and finish up the fuselage and then make one final check before I route out the battery box.

Jack
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Old Aug 28, 2008, 05:41 AM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Quote:
Originally Posted by jackerbes
Tony wrote:

"..Good looking build Jack, watch the weight in the tail!..."

Thank you, Sir.

I think I'm okay there. I checked it today it looks to be OK. I made a CG checker with a scrap of 1 x 6, two pieces of 1/4" dowel, two rubber dental pick tips, and some heat shrink. That will the the Genius CG Checker in the photo below.

With a small screwdriver and a stick of hot melt glue simulating the weight of the two servos that will go in the aft electronics bay, I was right on the money at 2-7/8" back from the leading edge.

I'll go ahead and get the servos mounted and finish up the fuselage and then make one final check before I route out the battery box.

Jack
Looking good Jack but I'd check the incidence to be sure it's about +2 degrees. Looks in the picture that your horizontal stabilizer is angled up at the same angle as the back deck. Maybe it's my eyes or the way the picture angle was when it was taken. I'll have another look.

Hey folks,

I have a chance to pick up a motor locally for a backup to the b21 and it's new but I'm not familiar with it. Any one know if the Onedime 2208-12 is any good???

Steve.
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Old Aug 28, 2008, 06:10 AM
Jack
USA, ME, Ellsworth
Joined May 2008
16,642 Posts
"..I'd check the incidence to be sure it's about +2 degrees..."

Humm... I thought I remembered that the KFm3 did not have any incidence and the UC wing had a few.

But I just looked at the plans and it does look like it shows about 1/10th of an inch over the 8" chord. I think that trigs out to about 0.72 degrees?

At any rate, I can add that with a thin spacer under the leading edge.

You must have a pretty good eye to spot that! Thanks for the help.

Jack
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Old Aug 28, 2008, 08:09 AM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Quote:
Originally Posted by jackerbes
"
You must have a pretty good eye to spot that! Thanks for the help.

Jack
My error. The plane looks fine. I thought the tail looked like it angled down to the back but on zooming into the picture I see it doesn't. I forgot about the KFm3 having 0 decrees incidence. Though I think the zero degree incidence we talk about is between the bottom of the wing and the horizontal stabilizer. The center line of the chord's lift plane, front to back, is not the bottom but angles slightly upwards through somewhere around the middle of the leading edge. That actually provides some positive incidence in flight. The plane of lift is parallel to the bottom of the wing only in a flat plate. Any Aeonautical Engineers out there jump in and correct me if I'm wrong. BTW, If you want to set me off just ask my opinion of Bernouli's Law.

Steve.

PS. Jack, The eyes are shot and these Filipino glasses don't help.
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Old Aug 28, 2008, 09:22 AM
I'm not flying backwards!
Tony65x55's Avatar
Oshawa, Canada
Joined Sep 2004
3,753 Posts
Steve, You have it right. Measured against the bottom of the KFm3 airfoil, there is no incidence. Your observation regarding the center line of the lift plane is also correct.

Tony
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Old Aug 28, 2008, 10:13 AM
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SergeyK's Avatar
United States, NY, Kings
Joined Feb 2006
854 Posts
BB24 Mainden report

Quote:
Originally Posted by dz1sfb
Sergey,

Beautiful! I really like the color scheme that you used here. Very easy to see and discern orientation. Can't wait to hear flight report. Stick with the lighter battery. You will be amazed at the difference that 18g will make at this scale.
Now I can authoritatively declare that it indeed flies just as good as it looks

Very nice, floaty. Takeoffs are no-event, very straight (unlike my Acro-bipe that I can't keep straight on the ground). Landings are almost vertical.
Did a bunch of touch-and-goes, some loops, tried some rolls.

Just needed a few clicks of trim. Might need to increase right thrust a little (keeps turning left at higher throttle). I have no problem compensating, but my daughter might complain. I hope she likes it, though.

I tries 3 batteries: 360mAh, 460mAh, and 910mAh, each one 10 minutes. Will charge tonight to see what I pulled. On the lighter batteries, it loops from level flight, on the heavier - a little dive is needed. But for a training flights, the heavier would work quite well.

Overall, an excellent plane

Hey, anybody is going to NEAT ? I'm going to bring this Blue-Baby there among my other stuff.

Sergey.
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Old Aug 28, 2008, 10:24 AM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
10,225 Posts
Sergey,

Congratulations!

Lighter wing loading is safer for beginners. Less likely to get into a stall or aggrevated stall, and easier to get out of trouble if you do get into it.

The 24"er got punch even in the wind.

Ken
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Old Aug 28, 2008, 10:43 AM
Foam Fighter and a Bloody Mick
grenadapult's Avatar
Hermann, MO
Joined Jul 2008
386 Posts
Well, I added a black stripe to the side of the fuse on my BB 60" AP1. I alo got video, which JHTitan was cool enough to post to youtube for me. STILL no crashes (Thank you FMS!!), and still no landing gear. The prop saver DOES save it, and stay away from gravel!! The kids in the video are some strays I picked up when they saw my plane. LOL! Welcome to scenic and historic Hermann, Missouri.

Tim's BluBaby, 1st great flight!

Thanks again for this design Tony!!!
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Old Aug 28, 2008, 10:43 AM
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SergeyK's Avatar
United States, NY, Kings
Joined Feb 2006
854 Posts
Quote:
Originally Posted by dz1sfb
Sergey,

Congratulations!

Lighter wing loading is safer for beginners. Less likely to get into a stall or aggravated stall, and easier to get out of trouble if you do get into it.

The 24"er got punch even in the wind.

Ken
Thanks. And I completely agree.
What I'm saying is that even 910mAh was still quite adequate for the model. I tried stalls and they were non-event. The only real limitation is that you can't loop from level.
So, if one was to train with this 24", I'd say the optimal strategy would be:
first few flights with 300-500mAh to make recovery safer, then one can train level flight with 900mAh for maximum duration, and return back to lighter battery for loops and tricks.

Oh, yeah, and it indeed was not bothered by wind.
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Old Aug 28, 2008, 11:30 AM
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jhtitan's Avatar
Washington MO
Joined Jul 2008
567 Posts
Video to follw

OK
so I went and maidened my 42"BB fuse last night with the 60"wing I had built. what it did could loosely be called flight. it stayed off the ground of its own accord but however I had no control and in the end picked up the pieces and headed home a little (read A LOT!) Frustrated. not sure what the problem was but she didn't seem to have any climb. I was expecting more thrust but couldn't seem to get any kind of flight. she kept nosing up and hanging or pulling right. I barely had any control and couldn't seem to trim it at all. gonna build a 42" wing and new H Stab for her and will see how she fly's this Sunday.
I have some video to post later and will let you guys give me your opinion of what my issue was.
thanks
Jon

And I forgot to add. Nice looking video Grenadapult. looking forward to Sundays flying
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Old Aug 28, 2008, 11:52 AM
Geaux Saints
Hopalong X's Avatar
Grafton, Il
Joined Nov 2007
1,913 Posts
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Mike
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Old Aug 28, 2008, 12:32 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,410 Posts
titan: when mine do that, it is usually tail heavy, or not enough down thrust. how did it glide power off?
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Old Aug 28, 2008, 12:46 PM
Registered User
jhtitan's Avatar
Washington MO
Joined Jul 2008
567 Posts
well the one or 2 times I tried killing the motor to bring it in it seemed to be ok. but I was normally too close to the ground. I was wondering about the down thrust. I may have to add a little more. I honestly wasnt payin much attention to down only to a little right for prop twist. I will look at it tonight
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