Tadpole Sub! Yet another strange BD project!!

[Larry Kuntz]

BD,
Your going too far.

BD,
Your going too far. I'm starting to hear sounds coming from your sub like " Hello Dave, I'm Hale, your computer. Sorry Dave, I can't allow that. Dave, stop touching me like that" Ha!

[Guest]

Ha,ha! Open the watertight doors,

Ha,ha! Open the watertight doors, Hal!

[bigdave]

But Larry,
Here is a

But Larry,
Here is a sub you don't have to paint.
It is just the boat for you!! BD.

[Guest]

Looked around sometime ago for

Looked around sometime ago for plastic jars suitable for one of these boats. Never found anything- Hellman's is still sold in glass jars over here in the UK!

Plenty of screw top plastic tumblers available, but unless it's disposable packaging, it doesn't seem quite right.

[raalst]

this is just a start

this is just a start of yet another hobby :
blowing your own (glass) WTC ! or, heck, your own glass boat.
imagine : NO SANDING !
from now on, Lexan is for losers

[bigdave]

Well she is done except

Well she is done except for the ballasting.
Looks like it will require a good amount of weight in the nose.
I think I will use shot for ballast.
Then melt it and mold it into a dome shape then attach the dome to the outside of the plastic jar with Marine Goop.
I will save a small % of the weight to add to the lower rod on the inside of the jar to keep her from doing torque roll.
Good news is a in water test showed no leaks!
Bad news is the motor is throwing off a SHIPLOAD of RFI.
I have three caps on it too.
I guess I will have to pick another motor.
You advance the ESC and both servos do a crazy dance.
Putting in a different motor will be easier than unscrewing the 32 nuts from the BLEEPING threaded rod!!
Who designed this stupid thing anyway!!
O! I guess I did!!
Here are a few more photos of the progress. BD.

[raalst]

you could try a smaller

you could try a smaller inexpensive motor in the wet, directly in the tadpole's tail.
will save you on ballast in the nose as well...

There, now you've done it. I get all creative now.
how about a foam outside in the shape of your favourite
sub, then add ballast until it does what a sub does.
It would be the subversion (ha, pun intended) of the dreaded
ARF plane kit.

[raf]

hallo

so the plastic jar is

hallo

so the plastic jar is not the right solution
the glas jar was already a part of the ballast

regards raf

[bigdave]

The glass jar is the

The glass jar is the best as far as easier to ballast.
I figured that when I started. But plastic was my only option.
It just added more to the challenge.
Looks like it will take about 18 OZ of ballast.
What I have done so far is to make a 12 OZ lead disc and have bonded it to the front of the jar with Goop. I used an old end cap mold and added molten lead. I guess you could say I made a lead end cap.
With this weight the Tadpole sits level in the water. Now the extra weight will be added to the lower rod at the CG.
I also corrected my RFI problem. I replaced the motor and it was better, then I replaced the R/X and it went away. Some receivers are more prone to RFI problems than others. BD.

[bigdave]

Well the ballasting is done.

Well the ballasting is done. All that is left is a test run.
Once I added the nose weight it was very easy to finish the trimming.
I ballasted the sub with the upper rod just under the water. It seems very easy to push under at this trim and the prop should not cavitate.
I still get a little servo twitching at times. I think it may be all the brass.
I may try and ground the motor casing to the brass assembly.
I even painted the sub (Larry) as I knew the brass would look really bad after a few runs in the pool.
I used Tug Orange and Tug Yellow.
I think it does not look too bad.
Once I confirm that is does indeed run and dive I will give all the info to Paul so he can do a basic plan. I will get some photos and video when she hits the water. Hopefully soon. BD.

[Guest]

How about fitting a couple

How about fitting a couple of LED's inside to light it up?

[bigdave]

I had the same idea

I had the same idea in mind.
A few bright white ones connected to the clear plastic to illuminate the jar itself. That would look cool. BD.

[bigdave]

I just wanted to post

I just wanted to post a quick photo. The Tadpole ran great untill it sank.
More info tomorrow. I am tired!! BD.

[bigdave]

Here is a short video

Here is a short video of the Tadpole in the pool.
We should have started the camera sooner as we could have gotten more footage.
At the end of this section she came to rest on the bottom which is not a good thing with a dynamic diver.
The problem was the O-ring seal I was using on the jar cap was too hard. The flexing of the jar caused the seal to leak.
This should not happen if a softer seal is used. But over all she ran great!! BD.

[Larry Kuntz]

Hey BD,
You really got

Hey BD,
You really got to get Steamboy to stop drinking when he's taking videos. Cheers Steamboy.