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Old Aug 08, 2011, 06:46 AM
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Originally Posted by jhtitan View Post
ahh, I think its the Elmers board I use Dollar Tree Redi Board. Its much lighter. Redi Board is covered in heavy paper, Elmers board is covered in poster board. I have built in both and the planes come out about 5oz heavier in elmers board on average, and on this plane it would all be on the tail.

that would be a big difference, if you have a dollar tree somewhere close, try that foam next time you build in it, it is also about 1/3 the cost.

Jon
Ok that makes sense and glad I understand the issue now. I do have a Dollar Tree about 1 mile from the office so I think I need to make a trip at lunch to stock up.

Thanks for your help!
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Old Aug 08, 2011, 06:50 AM
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For foam I use the blue "Fan Fold" foam that you can get from Home Depot or Lowe's. Home Depot sells the pink Pink Panther Foam and Lowe's sells the blue stuff made by Dow. Both are 1/4" thick which works with plans calling for 6mm foam. It costs between $35-$40, but you get 25 sheets that are 2'x4' each which means you pay only about $1.60 for each sheet, not a bad deal. Each sheet is enough to build a whole FunBat and then some.

You seem to very close attention to detail as your build looks very clean. Even using the materials you used I don't think that was your cause for failure unless they flexed and collapsed, which I doubt was it.

I hope you did put some reinforcement in the wing as per the instructions. My 1st FunBat did well until I flew it with my 1800mAH and then the wings gave out after a couple diving moves. I prefer my much lighter 1050mAh batteries since they put much less stress on the airframe and allow for more life. Even still, I think you should be able to make it work with your 2.2AH.

The biggest factor you need to be sure about where to balance this. I recommend some heavy duty velcro to give yourself a little bit of room for adjustement. If you have a nearby field with tall weeds or hay that would be an ideal place to work out the balance issue. But I found that the directions have you right where you need to be whith the balance line 1 3/4 inches back from the leading edge of the wing.

One other thing I would HIGHLY recommend is a prop saver which was not on the plane in your pic. If you are unfamiliar with these, they are a type of hub that allows the prop to spin as normal but if the prop collides with anyting it flexes instead of breaking. They only cost about 3 bucks and will save you in what you will likely spend in breaking props. And when you go this route, always double up on rubber bands so that if one fails you have another keeping things together. When you hear a funny buzz, check those rubber bands.

I tried building a bigger fuselage version to keep the prop away from the ground but that made the flight handling much worse and I still broke props.
The first two crashes would not have happened if I paid more attention to the servos - one was reversed . I did install a carbon fiber rod in the wing so it held up pretty well. Yeah I think I do need to get a prop saver as I did destroy one of the props in the second crash.

Thanks for the info!
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Old Aug 08, 2011, 06:53 AM
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Originally Posted by chris1379 View Post
Are you leaving the paper on the Rediboard?
on this plane, yes I leave the paper on. It adds a lot of strength, the foam core of readi board is pretty soft material and fairly thin. I have had a flight buddy build one after peeling all the paper off and got his down to under 9oz. It flew great with a small blue wonder size motor and a 500mAh 3s LiPo, but didn't survive the first crash. So if you plan on combat leave the paper, if you want to build one for a fun park flyer you can peel the paper off.

Jon
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Old Aug 08, 2011, 01:47 PM
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@ jathef, I feel your pain having flown my shortest flights with an unknowingly reversed elevator. I think about it in slow motion and it's almost funny (the nose is too low so I pull back which puts the nose further down so I pull way back and boom). Well... not so funny when it happens. After some time though. It has been teaching me to not be complacent with the basics. It only takes a few seconds to go through some plane saving checks. The juice is definitely worth the squeeze.

My next build will likely have the servos inside the fuselage. We'll see. I;m going to have some more fun with the FunBat 1st and see what else I want to change.
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Old Aug 09, 2011, 09:09 PM
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So far so good with peeling the paper. I have built several planes this way, including 2 Blue Funders and a Hobby-Lobby Yak. The Yak is mostly skinned with packing tape and the Funders had quite a bit. The failures I've had on the Funders were the fuse separating from the wing and stick. They were easily repairable. The Yak is fine except a slightly bent chin. I did the same thing on my factory kit so I can't blame the foam I'll try it without the paper and see how it goes.

I'm still not clear on the concept of folding the fuse and wing. I can't figure out how to cut a "V" at the fold line without cutting all the way through. I can cut the step away on the wing and sand a nice leading edge but what about the fuse? Has anyone built one by separating the pieces? If not, can you point me to a video of folding the fuse?

I'm currently cutting the parts and should be done tonight. I still have to decide what kind of control horns and linkages to use. I prefer Dubro EZ connectors but I don't have them on hand. I may use z-bends. Don't know yet. I'll probably use a 2408-21 motor with an 18A ESC and 800mah 3S lipos. Should be fast enough to be fun but not a screamer. The Funder has an 1130Kv motor with an 8x4 GWS prop and it's fast enough. Oh and no, I won't be doing combat. I'm still looking for park replacement for my long-gone Sig Wonder.

Chris
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Old Aug 10, 2011, 03:18 AM
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Is the laser-cut firewall for sale separate from the kit?
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Old Aug 10, 2011, 06:09 AM
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I'm still not clear on the concept of folding the fuse and wing. I can't figure out how to cut a "V" at the fold line without cutting all the way through. I can cut the step away on the wing and sand a nice leading edge but what about the fuse? Has anyone built one by separating the pieces? If not, can you point me to a video of folding the fuse?
you can cut the pieces separate and then bevel them and assemble them. I have done this many times in the past before I had my CNC, it makes cutting the bevels a bit easier. the folding of the fuse is just a 45 bevel on both parts. if you cut the bevels without separating the parts from each other then the paper on the outside is one continuous piece I am working on a new one for my self, I will see if I can get you some photos of what I mean.

and yes I do offer the motor mount separate on bloodymicks.com

Jon
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Old Aug 10, 2011, 04:25 PM
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BTW, did you ever finish the speed challenge plane? What was its top speed?
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Old Aug 11, 2011, 04:52 AM
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BTW, did you ever finish the speed challenge plane? What was its top speed?
no its still on the bench. I ran into some build issues that I need to work out. It will get finished. I currently have about 3 planes half built lol, bad habit to get into.

Jon
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Old Aug 11, 2011, 02:58 PM
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no its still on the bench. I ran into some build issues that I need to work out. It will get finished. I currently have about 3 planes half built lol, bad habit to get into.

Jon
True, so true. You'll get them done if you concentrate on one at a time. I am attempting to make my own firewall/ motor mount and I have some questions. Is the front part of the mount doubled or just a single thickness of 1/8 ply? How long are the side pieces of the mount? I'm thinking of extending them back a little further for some added strength on the sides. I also thought about some flat CF strips on the sides or even using drywall mesh coated in epoxy. I want to keep as much as possible inside the fuse for cosmetics but I'm leaving the lower nose open, hence the need for strengthening the sides.

Chris
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Old Aug 11, 2011, 03:41 PM
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True, so true. You'll get them done if you concentrate on one at a time. I am attempting to make my own firewall/ motor mount and I have some questions. Is the front part of the mount doubled or just a single thickness of 1/8 ply? How long are the side pieces of the mount? I'm thinking of extending them back a little further for some added strength on the sides. I also thought about some flat CF strips on the sides or even using drywall mesh coated in epoxy. I want to keep as much as possible inside the fuse for cosmetics but I'm leaving the lower nose open, hence the need for strengthening the sides.

Chris
The original mount (the one pictured on my site) had a double layer firewall, but that was because I could only find 1/4" long blind nuts. RTL Fasteners carries 1/8" long Blind Nuts in 4-40 thread so I modded the new mounts to be much lighter, the side plates are .75" wide by 1.25" long and the firewall is 1.5"x1.5" the tabs and slots for the side plates are .125"x.5".

They hold up very well to all but the hardest nose first crashes. I recommend epoxy not hot melt glue for gluing them up. I wanted them as light and strong as possible and to go inside the fuse not wrap out side of it. this mount is also designed to fit every plane I currently have on my site as well as most all of the rcFoamFighters planes as well. Some of rcFF's newer designs need a different motor mount style tho.

Jon
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Old Aug 12, 2011, 01:01 PM
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Thanks for the measurements. I got my motor mount glued to the fuse now. The next question is where and how to mount the gear. How much cooling does an 18A ESC with a 2408-21 motor need? I'm thinking of mounting the ESC inside the fuse on the underside of the wing. The battery would be directly under it in a velcro strap which puts them in very close proximity. The RX would probably end up outside the fuse on the side or under the wing. Would the ESC get too hot this way? it could be mounted on the outside of the fuse but I really want the battery inside. Are there pics of similar models so I can see how others did their gear? This is the part of a build that always stumps me.
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Old Aug 12, 2011, 02:59 PM
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Thanks for the measurements. I got my motor mount glued to the fuse now. The next question is where and how to mount the gear. How much cooling does an 18A ESC with a 2408-21 motor need? I'm thinking of mounting the ESC inside the fuse on the underside of the wing. The battery would be directly under it in a velcro strap which puts them in very close proximity. The RX would probably end up outside the fuse on the side or under the wing. Would the ESC get too hot this way? it could be mounted on the outside of the fuse but I really want the battery inside. Are there pics of similar models so I can see how others did their gear? This is the part of a build that always stumps me.
I personally like to keep my ESC's outside. Think of the foam plane like a foam cooler, it keeps the inside hot or cold depending on what you put in it. you can route the ESC's battery plug into the fuse though. Thats how I ran mine, rx on one side, ESC on the other with the LiPo inside between them.

Jon
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Old Aug 12, 2011, 03:10 PM
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I know my ESC has been fairly warm in the past but I've never burned one out and I would prefer to keep it that way. I also like to keep my electronics inside where they are protected from physical hazards. So what I like to do is make sure I always have plenty of airflow for the motor, the esc, and the battery. I have yet to lose one to overheating.

I did post a pic that showed my air intake resembling a bat's mouth. THis is with the larger fuselage but you can put incorporate intakes many ways, with a scoop for example.
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Old Aug 15, 2011, 11:41 AM
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I'm getting there. Here is what it's going to look like. Yes, it's very pink!
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