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Old Aug 28, 2011, 12:16 PM
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Japan
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CrazyBall clone

Hi all
I'm working on a clone of the CrazyBall:
CrazyBall RC Electric Foamie Plane | a DIFFERENT flying plane (7 min 58 sec)

Here's a bit more build info:
http://www.rcuniverse.com/forum/m_10385290/tm.htm
This fellow has made a clone and posted some rough plans:
http://bfishersc.wordpress.com/

I have a prototype almost done. I'll post more after I get it done. I'll keep working at it until I get a decent basic model working. At that point I can post some PDFs.
I have a few ideas for modifications, but want to get a basic model working well first.
Any and all help appreciated, as I am like many on here a beginner to RC and scratchbuilding.

Current prototype is using things I had around the house: 5mm depron, 1700kv bluewonder, 8040, 20Aesc, 9g servos, 3s lipos. It's a 60cm (24") diameter version. Obviously lighter is better if you can manage it, and a lower KV motor with larger prop would be quieter.
As far as I can tell the prop shroud is acting as an aerofoil and a thrust duct. This increases lift and adds stability to the round shape. The prop is mounted center, and the shroud is thick enough to shape the intake's inner edge round. There appears to be several ways to make this shroud. I'm trying 4mm corrugated plastic, although laminated foam carefully joined should also work.
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Old Aug 28, 2011, 05:08 PM
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Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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So that design is very interesting. I will be watching as I am very curious to see more about this guy. Is that 4 servo's I see? Not sure I would be able to fly this thing with an old Conquest with just dual rates & no expo or programming.
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Old Aug 28, 2011, 10:47 PM
Canadian Bacon
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Kingston, Canada
Joined Jun 2004
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Finally got some pics of one I'm building for a buddy. Here's the EPP ring being made. 2 layers of 6 mm. Hope this helps.

Gord.
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Old Aug 29, 2011, 06:44 AM
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Jimmy JFlyer's Avatar
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Joined Dec 2008
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I would like to see how the controls are set up.
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Old Aug 29, 2011, 08:34 AM
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Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
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Quote:
Originally Posted by Jimmy JFlyer View Post
I would like to see how the controls are set up.
It's set up like the Great Planes VFO, it can be either rudder/elevator or with mixing so that all surfaces move together.

http://www3.towerhobbies.com/cgi-bin...?&I=LXXYL8&P=7

Azarr

OK, I changed the link. The video is the 2nd one listed

Azarr
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Old Aug 29, 2011, 08:47 AM
Canadian Bacon
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Kingston, Canada
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Must be a glitch in the code. I get a (webpage cannot be found)

Gord.
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Old Aug 29, 2011, 11:08 AM
Old age is not for sissies
Azarr's Avatar
Dayton Intl, Ohio, United States
Joined Jan 2000
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Quote:
Originally Posted by flypaper 2 View Post
Must be a glitch in the code. I get a (webpage cannot be found)

Gord.
Fixed the link to just take you to the VFO page. The setup video is Video 2.

Azarr
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Old Aug 31, 2011, 08:56 AM
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UPDATE:
Sorry for the delay. I was off line and spent many hours over the last few days planning, scratchbuilding with stuff on hand, and troubleshooting.

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Special thanks to Gord for the bamboo pushrod idea. I was able to solve a lot of problems with these made from a sushi mat of all things.
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I had a feeling it was going to be too heavy and brittle, but decided to see it through anyway. Total completed weight is 400g without lipo. 1000 3s is 90g. So the AUW/thrust is close to 1:1.
I accidentally folded shroud on installation, but was able to rough it.
I also noticed I made a mistake on mounting the elevon servos. I'll have to mount them on the top of the wing, as the pull is full power, but the push is weaker and often flexes the rods or loosens the connections.
I mounted everything as far forward as possible. The lipo-less COG is at the rear of prop shroud. With lipo I can get CoG at about front of prop shroud. I also put lipo down, as IIUC front/low Cog is easiest flight characteristics.

I finally got to do the maiden today and it didn't go well. I need full throtle to get takeoff, and couldn't keep it up for more than a few seconds. Half the time it would suddenly lurch forward and dive (under full throtle) into the ground with a huge "THUD". I'm amazed the fuselage survived at all. Lots of rod flex, so servos OK.
At this point not sure what to do with it. Any ideas?
I'm thinking stiffen rods, remount elevon servos, and try again. Other than that, maybe a new build, smaller diameter and lighter using all single layer 5mm depron (dollar store foam board). I'll need new smaller lipos then, as it will be very fragile I imagine. Maybe that small and heavy will be too squirly to fly?
I would love to use EPP, but no idea where to get it at a reasonable price. Gord, how did you square the vanes? I just eyeballed it. Looks like you notched the rudders for clearance? I used 4mm corrugated plastic sheeting for the prop shroud, very tough, but more than double teh weight of 5mm depron. I test made a depron prop shroud and was surprised it worked well on a small diameter 8" prop, but you need to be very careful not to crack it until its laminated and epoxied.

Any ideas what to do at this point?
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Old Aug 31, 2011, 10:31 AM
Canadian Bacon
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Yeah, way to heavy. Think Light Mine is 184 grams and Brians is 182 grams. Your foam itself is light enough. I'd get rid of the coroplast ring and the scotch tape and see what it weighs. The paint itself adds a lot of weight too. I only added enough paint at the front for orientation. Maybe better to start from scratch. I just weighed the bare foam frame with the ring and ails for a buddy as shown above and it weighs 92 grams, to give you an idea. This is the 20 in. version. The ring id. on mine is 9.5 in. and the prop is 8 in., so the prop in the tunnel doesn't work in this case. To get the ail. size, I measured out from the foam at 2 in. at the trailing edge. 3.5 in forward to the hinge line, and hinge line measures 1 in. from the centre to get the angle. For the length of the ail., from the inner trailing edge to the outer tip is 9.5 in. Sounds pretty mixed up so I'll see if I can make a pic later. If you can, go with the smaller 5 gram servos for weight purposes. For pushrod guides, I use plastic drinking straws, about 1/2 in long, you can slit them from end to end and tuck the pushrod in. The plastic is stiff enough to keep it in. Here's one on the side of a HK MIG 15 You can make a Depron V to space it the necessary distance away from the fuse. Remember Light Is Right

Hope this helps
Gord
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Old Aug 31, 2011, 05:19 PM
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Ya, I'm thinking a new build is a good idea.
That paperweight has a lot of hours in it
How are your reinforcement doublers set up? 1 on each elevon and 2 on bottom rudder? Did you just eyeball the 90 degrees when connecting the 4 vanes ("wings")?
I'm thinking of making a really small one, as light as possible, as I'm using an 8" prop. My on hand electronics weigh 75g, 4 9g servos and fixings 50g. So 125g + fuselage + battery = ?. That's a lot heavier than your guys' stuff, so this project may be doomed.
The depron I'm using is stiff but very brittle. Comes in nice 3'x2' sheets in different colors for about $4. That 24" one I made was from 2 sheets exactly, with enough for a prop ring.
Maybe I could make an 18" or 20" ball.
Maybe its bets to buy all new electronics for a new one. I really want a whisper quite safe flyer to use at the tiny parks near my house.
I'm wondering if the 1/4" clearance on the prop shroud is worth all teh shredding thats bound to happen. You may have it better with lots of room.

If shipping isn't too bad, I thought of getting one from the "gittarpikk" and save some hassle. These might make good presents for kids here. I put in a request but haven't heard anything back. The guy doesn't seem to want to reply.
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Old Aug 31, 2011, 09:13 PM
Canadian Bacon
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Kingston, Canada
Joined Jun 2004
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Hi Jonny: Don't know how your electronics comes out so heavy. my rcvr, ESC and 4 servos comes out to just 42 grams. 430, 3 cell batt also weighs 42 grams. The pic in post 3 shows the half moon cut stiffeners. One for each wing if you will. I just glued in the ring and the 1/32 ply firewall, so the foam plane comes out at 90 grams. So the electronics is 42 grams, the batt. 42 and the foam 90 for 174 grams total . Still need the pushrods, surface horns and paint which should come out close to that 184 grams that my flying one comes out to. Yeah, I did just eyeball the right angles.

Gord.
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Old Aug 31, 2011, 09:20 PM
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Oh, so each 'wing' gets 1 stiffener, on 1 side. Do you see any yaw drift? The reason I ask is that I imagine teh stiffeners act as KF steps to generate lift, so I was worried about asymmetry on the vertical axis.
I'll double check the electronics again.
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Old Aug 31, 2011, 10:13 PM
Canadian Bacon
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Kingston, Canada
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I never did cater to the KF thing. I've used these doublers on many different planes and couldn't find any difference in performance. No yaw drift that I can tell.

Gord.
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Old Sep 02, 2011, 12:17 AM
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I re-weighed everything, and all electronics are: 77g + 52g (4 servos+horns, etc.)+ pushrods 6g= 129g total. Lipos are 1000 3s 91g. I have 3 of those in new condition. I have 1 battered 800 3s I can try at 67g.
So 129g, plus lipo. Using these lipos and electronics that either 220g/196g. Plus airframe. Maybe too heavy for this type of 3D model.
I guess 20" is about the smallest you'd want to go? Is that the size most people are using?
The depron sheets I am useing are 155g for a 3'x2' (90x60cm). These are very stiff, come in all colors, and cost about $4. I can buy them just down the street.
I could make an 18" (45cm) version from 1 sheet. This would include 1 doubler per side as you've done, as well as a depron prop shroud. With a 3s 1000, that would bring the weight to about 375g+.

Alternatively, If someone was going to make a perfect version of this, what foam and electronics would you order?
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Old Sep 02, 2011, 06:20 AM
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Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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One thing I would keep in mind is just going as light as possible.
Take a peek at this link to RCRich's version called the angry fish. He made his RET only to keep it simple. It flies real well. Maybe thumb through it and check out what he is using too.

http://www.rcgroups.com/forums/showt...ighlight=angry

ok back to getting ready for work.
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