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Thanks Jim, 
I'll send them a note today.
Here's what will work, let's see if they will print them in this tiny scale.
I'll send them a note today.
Here's what will work, let's see if they will print them in this tiny scale.
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A nation of sheep breeds a government of wolves -
hopefully they wont loose too much detail in the size you need"Our society strives to avoid any possibility of offending anyone except God.
Billy GrahamComment
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This looks great Dr jet. My only comment is that from a scale perspective the stacks is are too far forward see here
Sent from my Moto G (4) using Tapatalk"Our society strives to avoid any possibility of offending anyone except God.
Billy GrahamComment
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Let me finish prototype testing (another week or so) and I'll let everybody know about availability. The kit will include a motor mount and I really think I should include the 1/16" stainless steel tube and 1/32" wire to make the wire drive and water-tight rudder push rod.
I highly recommend helicopter outrunner motors for a number of reasons. They are fan-cooled which eliminates the need for water-cooling plumbing (takes up a lot of valuable space). They have a lot of torque for a given Kv so they can spin a decent-sized propeller. They are compact (short). And lastly, they can be had for a very low cost (sometimes under $10). These's no need for a $100 NeuMotor in these, the cheap Chinese outrunners will easily over-power the hull.
See photos for battery, ESC, servo, and Rx locations. I've modified the motor mount side supports and bulkheads to facilitate putting the battery and ESC in the shown locations.A nation of sheep breeds a government of wolvesComment
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Yes and no. Look where the stacks are in relation to the hole for the engine air intake. I think the "scale" issue is that the cowl is too long. Nothing a few minutes on the belt sander can't solve.This looks great Dr jet. My only comment is that from a scale perspective the stacks is are too far forward see here
Sent from my Moto G (4) using Tapatalk
A nation of sheep breeds a government of wolvesComment
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After Jim brought it up, I've been looking at the cowl and he's right: Something was amiss. Realize, I essentially traced the cowl shape from Garry Finlay's plan without studying photos of the actual boat. After I looked at a lot of photos, I realized that I would have to make the hatch quite a bit wider to make it work. I didn't want to do that for a lot of structural and building issues. I decided to keep the hatch as-is and just deal with a "skinny" cowl.
Well, The existing cowl got a short ride on the belt sander and lost about half an inch. It looks much better now. The laser-cutting drawings received a similar slimming process. Regarding to the actual building process, I mounted the stuffing tube and even went so far as to order some blue paint for the hull.
I've been perplexed as to how I could sand the bottom of the hull in the area between the air traps and the tunnel sump while keeping everything sharp and square. Note: As it sits right now, some of the edges are sharp enough to draw blood!!
The wood sanding blocks I had been using just weren't the ticket. I bought some Delrin blocks that should do the job. They have good sharp square corners, they don't flex, the "un-sandpapered" sides won't scratch, they're waterproof for when I use wet-or-dry; they're the ticket. 
I have adhesive sandpaper in several grits and I use spray adhesive to attach the wet-or-dry. The clean, hard, sharp edges of the Delrin blocks allow me to trim the sandpaper right to the edge with an X-Acto knife without the sandpaper going past the edge to create a groove on the surface adjacent to the one being sanded.
LOTS of primer going on with the occasional schmear of really "dry" epoxy/Cab-O-Sil mix. It's a drag that the epoxy takes 24 hours to go off unless I heat it. I've discovered my oven will go to 125° and the balsa/plywood is just fine at that temperature. Think putting it in a rock garden in Phoenix sometime in August.....
Photos to follow.A nation of sheep breeds a government of wolvesComment
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Shortened Cowl
What a difference half an inch makes.
UPDATE: I've also lowered the height of the cowl at the rear. It's starting to look like something now.Last edited by Dr. Jet; 01-25-2019, 08:04 PM.A nation of sheep breeds a government of wolvesComment
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Winging It
It's time to fit the wings. Each fin/wing is a sandwich of 1/16" balsa and 1/32" ply. The ply has notches in it to allow for the insertion of 1/16" carbon fiber rods. The hull and wing mounting holes in the fins will get pieces of 3/32" brass tube that the CF rods will go into to hold everything in place.A nation of sheep breeds a government of wolvesComment
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I looked at the new photos where stuffing tube and coupler area and am wondering the space allowed is too much. I run flex of which I leave 3/8" space. Will the wire flex with that spacing?Comment
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That's not the wire between the coupler and the stuffing tube; it is a stainless steel tube (with the 1/32" wire glued inside). Remember, this is about a 200~250 Watt system; the stainless steel tube is more than stiff enough for this application and the brass stuffing tube provides excellent support. I've used a similar arrangement in the Micro Scat Cat Twin with great success.
The key to making this system work is the alignment of the motor and the stuffing tube. I mount the motor and coupler in place and use a piece of 1/16" brass tube or straight music wire of the proper length to mark the location of the exit hole on the floor of the hull (I made a slit in the floor piece to get you close). When I make the hole, I make it slightly oversize to allow for some adjustment. Then I put the stainless steel tube into the coupler (it will stick out of the bottom of the hull) and insert the stuffing tube over the SS tube. I rotate the motor to look for any horizontal or vertical movement of the stuffing tube. If it does, something is out of alignment and I enlarge the exit hole as necessary.
When everything looks copacetic, I tack the stuffing tube into place with a TINY drop of CA, then remove the SS tube. I re-insert the SS tube to make certain it slides directly into the motor coupler. If it doesn't, there will be friction in the system and I re-adjust and repeat the procedure until the alignment is perfect. Once it is, I re-assemble the SS tube back into the coupler to help hold everything in place. Then, I tack the balsa-1/32" ply-balsa sandwich stuffing tube support in place, and epoxy everything.
One final note: K&S does not make 1/16" SS tube. After searching long and hard, I have located a source for high quality 304 stainless steel tube. I will include enough in the final kits to make the drive shaft and the rudder pushrod, which uses a nearly identical arrangement.A nation of sheep breeds a government of wolvesComment
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Better Cowl Profile
Here's the "Improved" cowl profile. I think Jim will approve. I do need to make it a bit thinner aft of the exhaust stacks though. It never ends.....
A nation of sheep breeds a government of wolvesComment
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Somebody Stop Me!
So as I'm getting close to finishing the design of this kit, I got to thinking: What's next??
I have an idea!!
A nation of sheep breeds a government of wolvesComment
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Well, for "ships and giggles", I started working up some drawings for a classic round-nose shovel (actually, there is a tiny bit of a point on the nose, but I digress....). The first thing I noticed is there is a WHOLE LOT lower parts count. I'm also going to eliminate the 1/32" ply parts that were in the Atlas and substitute 1/16" ply instead, in an effort to keep cost and complexity down. This should be a snap to build.
But, I think there may be an issue; or better stated: A challenge. The MHZ and H&M micro shovels were occasionally prone to blowing over with a small 3000 Kv motor and 6~7 NiMh 1000mah cells turning a 29mm x 1.6P prop. I'm planning on powering the Atlas with a considerably larger 3550Kv motor on 2S LiPos and will start with smaller props. The Atlas, with a more modern "pickle fork" hull may do just fine with the additional power, but a light-weight shovel may get a lot of "air time"
That's where the challenge will be: Keeping them on the water. 
I'm not going to produce any parts until the Atlas and the Twin Cat are finished, but I will be refining the design so I can produce a prototype kit quickly.A nation of sheep breeds a government of wolvesComment
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