Bud Nosen 1/4 Citabria conversion

[Mucksmear]

Hello,

Thought I'd finally get around to posting some progress after a year or two of stalled or insignificant work on this project.

Started out as a gas job over 15 years ago with a Zenoah G23 as the intended powerplant. Finally a little over 5 years ago I got the bug to finish it. Now two kids later I'm finally on the final stretch.

Progress thru 2005 can be seen here:
http://www.elliotfan.com/art/flight/citabria/cit_img_01.htm

A 79Ah AGM field battery should be arriving in a few days. That should get me about 3 or 4 charges at the field.

Here she is unpainted as of a couple months ago:

[Brian Allen]

Nice looking Citabria. I flew one for years with an OS160 twin and it was simply great. Wonderful flyer but the kit is a bit of a bear.

I have a kit in the stash that I want tobuild up one of these days for E power.

Let us know how things turn out.

Brian Allen

Veni Vidi Volavi

I came I saw I flew

[Mucksmear]

Thanks Brian. I'm currently trying to figure out how I can get it to the field without folding down both passenger seats so my son can join me at the field. She's 99% painted now, minus a couple of minor details. Will post a pic when the weather clears and I have time.

Should be around 1100 Watts with the Torcman 430 pulling arounod 37A from 30 GP3300 cells.

[staggerwing]

I have one of these w/ a Q35, an older build I just re-painted @ 18.5 lbs RTF.(more masking than I care to do right away again)
I think it's a tad heavy to think about converting for it to fly aerobatically. What is AUW of yours ?
Will soon be posting pics of my 96" Bridi Rearwin Speedster w/ Hextronic C6374 on 8s. Not sure about this power train till I test it---waiting on 12s ESC now finally being shipped .

Bob

[Mucksmear]

AUW looks like it will be 19 lb, 11.5 oz.
I had originally estimated 16 to maybe 18 lb, so she's a bit heavy.

The 30 cell pack is about 5.8 lb

[hermperez]

what paint are you going to use?

two dewalt lipo packs would be 3.1lbs, 10s2p at 4400mah, about $220 total. Make sure you cycle those gp3300 about 3-5 times to wake them up before the first flight. With nice slow overnight charges to equalize all the cells.

[Mucksmear]

I used latex house paint (Behr) over a medium grey surface coat, brushed on with a foam brush. I also mixed in Flowtrol. I'll try to post some pics this weekend.

Yep, plan to cycle/slowcharge the cells - I bought them a while ago but they haven't really been used except for a couple very short test runs of the motor.

The 2 Dewalt lipo packs sound interesting. Can't afford that right now... Can you tell me more about them? Where do you get them? Do you need to modify them or break them out of a battery case or anything like that?

thanks
-E

[hermperez]

I am really interested in that painting method, how do the brush streaks look?, sure is a lot less work than spraying. You used semigloss or gloss paint?

The A123 cells are very popular now for big planes and helis.. I buy them at Ebay for usually $95-$110, shipping around $10.. you have to break apart the cases, remove the 10s1p packs and attach a couple of leads to them.. usually I reconfigure them slightly and add balancing taps to them.

You can use a heavy duty nicad charger along with a special adapter that will stop the charge at a certain point. Here is the adapter and the a123 cells:
http://www.slkelectronics.com/lipodapter/index.htm

[Mucksmear]

I used interior semi-gloss enamel.

Next time I may go with flat and then use a clear spray (acrylic or poly-U) to achieve the desired gloss, semi-gloss or whatever finish. Flats dry faster and I think they cover better in fewer coats as well.

I alternated the orientation of my brush strokes between coats to get the cross-hatched appearance of fabric. Solartex already has a fairly fine weave patter. If I had used more Flowtrol, I suppose it's possible that the Solartex weave would have come thru, but my paint was on the thicker side. Definitely make a few test scraps out of the same material/covering of your model first.

Best part: I could paint after the kids were in bed - no fumes, no overspray, no air compressor noise, water cleanup, cheap paint, computer color matched (they still screwed up on that one though).

[Mucksmear]

Ok, great weather today so I took the Citabria out back and took a few shots.
Pretty happy with how she came out. Stand off scale if you will. The strut system is more Cub like than Citabria, but it looks scalish so that's fine by me. Also did a motor test run. Got 42A static, but that quickly droped down into the mid 30's.

Right now, this evening I'm cycling the cells as they've been sitting around for quite some time. They're in solderless power tubes so if need be, I can easily balance or test individual cells.

-E

[hermperez]

Good luck with the cells, I never have any luck with nimh that have been sitting for a while. Plane looks pretty good..

I love that picture with the kids!

[Mucksmear]

Had a successful maiden flight this afternoon!

I started this kit about 18 years ago and now it's finally flown.
No hard numbers yet as time was limited.
Had the field to myself (and family). I estimated a 7 - 8 mph wind at about 5 or 10 degrees off center line at our BARCS club site (Richmond, CA), .

Takeoff roll was very short (thanks to headwind) and climb was steeper/better than expected, eventually ended up with many clicks of down elev trim. Ailerons very effective, but as expected, lots of rudder needed to make nice turns (didn't do too many of those today). Cub-like "performance".

I made a total of 4 circuits. A little bouncy on the landing (a bit turbulent down low). Will try to post some video soon.

-E

[Mucksmear]

Video's a bit choppy, compression's too high, and the touch and go's very bouncy. I can fly smoother, honest!

Video:

-Edit:
Video's now "higher" quality and split in two:

1st flight:
http://video.google.com/videoplay?docid=7332365915872600925

2nd flight:
http://video.google.com/videoplay?docid=5443121935194526962

-E

[KOMET 44]

Mucksmear,Nice test flight and video.Have fun with the future flights.

KOMET44

[Mucksmear]

Couple more pics from the 2nd flite. Established that she'll cruise at 1/2 throttle.

Once again, shamefull landing "technique". You can clearly see that I dropped her onto the runway. Still need a calmer day with several consecutive flights to explore flight characteristics and to test the possiblity of 3 pointing it or at least rolling her in on the mains.

Appended the 1st flite footage with 2nd flite footage - somewhat steadier camera work:

http://video.google.com/videoplay?docid=7112285313760656515

-E

[megawatt]

Woo hoo Mucksmear, she's a beauty!Looks like she likes to fly fast.Not sure how I ever missed this thread.Great job!I haven't had a chance to put anymore flights on the Cub yet, but hope to do so soon.

So,what is the span,area ect of this model.Also, what esc are you using.

Jeff

[Mucksmear]

Hi Jeff,
Thanks - just saw your query in your thread, but since you're over here, I'll just answer it here!

Winds were blowing between 5-10 possibly 7-12 mph, roughly down the runway, so going downwind she picks up quite a bit of ground speed. I need just the right convergence of free time and calm conditions... still waiting.

Span: 108"
Area: 1550 sq. in.
AUW: 19-1/2 lbs.
Torcman 430-30 10pole
APC 20 x 8 (thin electric)
GP3300 nimh x 30 (Initial pack voltage: 40.7V)

At full throttle (static):
5880 rpm
30V-31V
39A
That's roughly 1206 Watts static.

I'm curious what your voltage and current draw is at 1/2 throttle (static).
-E