Scratch Build - 29" Balsa Stepped Cat
#1
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From: Centerville,
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Well since everyones complaining that the forum is dead, I figured I'd begin posting on my current (1st) build project. I saw a post here about a year ago about a balsa cat and couldn't forget about it. "Shockerman" designed the original one based on picture of a full sized Callan Marine boat. There's a great build thread on RRR. Ive increased the size from 26 to 29 inches, full scale and then added about another inch to the width of the tunnel. The boat will be about 29" without the running hardware. Right now I plan on skinning it like he did with 1/32 balsa under 1/64 ply and then coating it with urathane. Power will come from a 9XL through a hydra 120 to a standard flex drive and either fullers or SM hardware. I'll start testing on 12 cells with likely a 637. I'm thinking of making some changes and puttin the rudder on a pylon further back and directly behind the prop. Any advice or feedback is welcome.
Word of warning I have a lot of other things on my plate so this one will require some patience for all of us.
Dayton
Word of warning I have a lot of other things on my plate so this one will require some patience for all of us.
Dayton
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From: , MI
Hi I'm interested in seeing how you build your boat from balsa. I'm thinking of building a hull from scratch but I've never done that. My prior boat was a RTR model that I modified.
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From: Centerville,
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Same here, how hard can it be?[&:]. I'll tell you what I did but I won't garuntee that it's the best way. I think it's all a matter of stregnth vs. weight, but I have a feeling that this boat will be strong and light by comparison any way I do it. The question is to I want to copromise weight for stregnth or stregnth for weight? I think I'll go farily conservative and keep it pretty stout. I still need to do some research before I apply the second layer of wood.
#6
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Thanks Ryan. Hopefully I'll start skinning it this weekend. I need to keep my momentum.
Thanks Ryan. Hopefully I'll start skinning it this weekend. I need to keep my momentum.
If you believe you may use LiPo or even a more powerful motor in the future I would recommend building strong vs keeping it light. It's much easier to over power a boat in the future vs swim for the pieces after a blow over.
Ryan
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From: Centerville,
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I've seen the only working prototype of this boat blow over going fast and it came back to shore under it's own power. The builder claims the hull is very rigid. It'll be full of foam too. I'm going home to work on it.
#9
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From: Centerville,
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OK then who did? He said he caded it from photos of a full size Callan. Do you credit the cad guy, the original designer of the full size or the photographer?
Do you know something I dont?
PM

Do you know something I dont?
PM
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From: Tottenham/Orillia, ON, CANADA
i recall him saying that it was not him. it was a german fellow. I have his email as well. Just forget which it is.
I remember when i wanted the plans a while back he said sure but didnt want to give alot out because they were not his
I remember when i wanted the plans a while back he said sure but didnt want to give alot out because they were not his
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From: Centerville,
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Not accurate.
shockerman80 said:
http://www.rcuniverse.com/forum/m_58...tm.htm#5891948
He was a little hesitant to send out the design until he got it running good. He sent them to me but not the autocad, just an adobe file. I don't recall any germans involved. He sent the plans to a ton of people but I haven't seen a build yet.
another quote from shockerman80 the RR forum:
shockerman80 said:
Heres a link to the cat i designed. If theres enough interest ill post the info.
He was a little hesitant to send out the design until he got it running good. He sent them to me but not the autocad, just an adobe file. I don't recall any germans involved. He sent the plans to a ton of people but I haven't seen a build yet.
another quote from shockerman80 the RR forum:
Yes i did all the cad drawings first then built it. I am a cad teacher and the drawings are pretty close or my building skills are a little off so i have to make some minor changes to them. I honestly drew the boat off some pictures of the callan marine boat with some rc specific changes. I still consider the boat my own design though. Im not going to send out the drawings till i run it. i dont want anyone else to build it if it has any major mistakes such as bad handling characteristics.
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From: buffalo, NY
i did design this hull. there was another hull that i built that i did not design. the 26" balsa cat was completely my own design It took me almost 2 months to design it.
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From: Centerville,
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They do look the same. Yours was cut with a laser and mine with a scalpel. That would have been faster. I'd have tried to cut it on our abrasive waterjet but as you know I only have the prints. Did you get that from Shock? Did you widen the tunnel on yours? I bought some additional supplies this weekend, but no progress as of yet. I'd say I think about it for at least 1/2 hr a day but no action right now.
#21

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From: Tottenham/Orillia, ON, CANADA
no i did it my self. its not hard when you are good at cad.
i did widen the tunnel and did a bit of changes to the sponons
i did widen the tunnel and did a bit of changes to the sponons
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From: Centerville,
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Ryan,
Watch me for a while. I'm very sarcastic. If wasn't large I'd likely be dead.
Next "step" no pun intended is to put a 1/32 skin of balsa over the all the bottom surfaces. I plan to start with the tunnel and then the bottoms of the sponsons followed by the sides. Then I'll urathane the interior, add foam and then do the top. Then repeat with 1/64 ply, and urathane the outside. Im not sure how I'm going to bond the ply to the balsa but I'm going to try to cross the grain as much as possible to increase the stregnth.
Watch me for a while. I'm very sarcastic. If wasn't large I'd likely be dead.
Next "step" no pun intended is to put a 1/32 skin of balsa over the all the bottom surfaces. I plan to start with the tunnel and then the bottoms of the sponsons followed by the sides. Then I'll urathane the interior, add foam and then do the top. Then repeat with 1/64 ply, and urathane the outside. Im not sure how I'm going to bond the ply to the balsa but I'm going to try to cross the grain as much as possible to increase the stregnth.
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From: Hudsonville,
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ORIGINAL: Taylor Shaw
ours look the same
mine has been like this for a while. to lazy to finish it, don't know what to do with it
ours look the same
mine has been like this for a while. to lazy to finish it, don't know what to do with it



