Vic Smeed’s Hydro-Bat

[OVERLORDParticipant @overlord]

Hi All,

In the thread "Vic Smeed's model boat designs" my build of the Hydro-Bat was mentioned. It keeps me busy for a few months now and I'm enjoying it. The model will be powered by a Black Lynx engine made by Model Engines in the US. It's in fact a modern Cox engine made with performance parts. I won this engine with a picture contest on Cox Engine Forum. The build is coming along well. I did a small modification on the rudder because I didn't like the rudder arms and push rod above the deck. I also changed the canopy. It became a bubble canopy with dashboard. Plan is to fix a pilot figure afterwards.

Some pictures:

(I can't figure out anymore how to insert a picture, I did it before though. can someone explain? th.

Lieven

[OVERLORDParticipant @overlord]

[ashley needhamParticipant @ashleyneedham69188]

Hi Lieven. Look at the home page FAQ bit. Basically you create an album, put pictures in it and these can be put into a posting.

​Performance parts for a Cox engine!!

Ashley

[OVERLORDParticipant @overlord]

Thanks Ashley, All clear.

[Dave MilbournParticipant @davemilbourn48782]

Coming on nicely. Incidentally I've never needed more than tinman's {soft} solder and Baker's Flux to fit a rudder blade to a shaft, as long as you cut a slot in the shaft to fit and peg it with 1/16" dia brass rod. As you've found, brazing can be cruel to thin brass sheet and the high temperature will soften the brass rod and allow it to bend easily.

Dave M

[OVERLORDParticipant @overlord]

Thanks Dave for the tip. On this model, the rudder stock is only 2mm in diameter. The rudder blade is stainless steel. That's why I had to silver solder the 2 together. The rubbish you see in the picture is the flux on the blade. After cleaning, it looked like this:

[Dave MilbournParticipant @davemilbourn48782]

That's two lessons for Kevin, then!

DM

[Andy CParticipant @andyc56856]

Okay so how the heck do you saw a slot in a rod that small?

Andy

[OVERLORDParticipant @overlord]

Posted by Andy C on 08/09/2017 07:01:00:

Okay so how the heck do you saw a slot in a rod that small?

Andy

I didn't. The rod is just put on top of the blade. That's what Vic must have done when making his prototype. According to the plan, he uses 1/16 piano wire. The blade was cut from a paint scraper or putty knife. The central fin was made from the same material. I think it's a little less than 1 mm thick.

[OVERLORDParticipant @overlord]

Posted by ashley needham on 07/09/2017 08:28:26:

​Performance parts for a Cox engine!!

Ashley

**LINK**

[OVERLORDParticipant @overlord]

Yesterday, I finished the hull.

[ashley needhamParticipant @ashleyneedham69188]

Master. How will you access the inside for battery and equipment fit and so on ?? Will you have a man in the dome? Ashley

Killer bee crankshaft !!!! my word.

[Dodgy Geezer 1Participant @dodgygeezer1]

Posted by ashley needham on 13/09/2017 17:46:09:

Master. How will you access the inside for battery and equipment fit and so on ?? Will you have a man in the dome? Ashley

Killer bee crankshaft !!!! my word.

Looks like the dome is at the centre of a balsa hatch…

[ashley needhamParticipant @ashleyneedham69188]

I thought as much. These things are usually very wet on top. Water exclusion is always an issue.

Ashley

[OVERLORDParticipant @overlord]

The article in Grid Leaks by Vic says to sheet the entire model and then cut out the hatch for access to the radio compartiment. The hatch will be fixed with "surgical tape". I don't know what that looks like but I'll use sticky tape. The dome will have a pilot. It's a light plastic pilot figure of IM Products of Japan. I have since I was a youngster. Finally I could find a use for it. The dash board is already in place.

[ashley needhamParticipant @ashleyneedham69188]

One method of sealing the hatch is simply to (once the gear has been turned on and found to be working ok!) stick clear sellotape over the edges of the hatch. As long as the gloss paint is well adhered to the balsa there should be no issues with ripping bits of paint off, and the tape is undetectable once on the water. It is also 100% waterproof and easy to do.

Ashley

[Dodgy Geezer 1Participant @dodgygeezer1]

Posted by ashley needham on 15/09/2017 07:51:04:

One method of sealing the hatch is simply to (once the gear has been turned on and found to be working ok!) stick clear sellotape over the edges of the hatch. As long as the gloss paint is well adhered to the balsa there should be no issues with ripping bits of paint off, and the tape is undetectable once on the water. It is also 100% waterproof and easy to do.

Ashley

If you are worried about pulling the paint off, run your finger once over the sticky side of the sellotape. This will suppress the strength of the adhesive a bit, but leave it still capable of sticking to a smooth surface….

[Trevor HollowayParticipant @trevorholloway99134]

I have also found that "Scotch tape" is better suited than "Sellotape" as it is less sticky and leaves no residue.

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