Off the shelf and into the drink...MTB ahead.

[ausf]

Been staring at this box far too long after snatching it up as a preorder, can't wait to build...

The Italeri Vospers MTB. I did try to start this once, but was shorted a sprue. They only replaced it after sending them the box UPC as proof, so the length of time was enough to for me to lose fo c u s.......

Anyway, I'm planning on running this beast on three brushless motors, to get the proper scale movement.After waiting on the motors from Hong Kong, I slipped while pressing the shaft out (these motors are designed for planes and don't hsve an exposed drive shaft) and bent a housing. So while waiting on the new motor, I'm skipping my normal urge to box it all back up, andI'm moving astern to making rudders.

I copied the kit part in brass:

Mounted them, icluding the linkage for the servo. Once I mount the servo, I'll go ahead and glue this to the hull and thin coat the seams and connecting points with marine epoxy. One set, I'll add all the detail parts.

 

[Sherman 18]

WOW!

 

[Swordsman]

Nice work .... looks very original ... :captain

 

[moon puppy]

I be the hardest part was getting that brass tie rod right.

 

[Paulw]

that looks real cool. What are the dimensions of that transom?

 

[Hippy Ed]

 

[iambrb]

neat!

 

[ausf]

Thanks guys.

Bob, it was easy to make, but you're right about calibrating. I was amazed how much the rudder blades would change based on the slightest change. It seemed that just applying pressure by pinching with my thumb and forefinger was enough to tune it in. I seesawed back and forth for about a half hour before it was dialed in.

Paul, it's 1/35, so the stern is about 4 inches wide.

 

[Jeeves]

 

[ausf]

Got the guttywuts installed, I'm going to try to run it with three individual controls so I can steer with the motors. I have no idea how it works, my only experience with the idea was my friend was going for his master's license for multiple screws, so I guess there's a science to it over a single engine.

We'll see.

 

[moon puppy]

That's cool! Guess backing one screw will help make a tight turn? Would that work at high speed though?

 

[Sherman 18]

:skipper

 

[ausf]

That's cool! Guess backing one screw will help make a tight turn? Would that work at high speed though?

I hope so, I'm not sure how it'll react. The RC guys think using three screws is absurd, too much work and not worth it in scale. But to me, it'll aways be a model first and will spend much more time on the shelf than in the water, so I'd prefer scale props and rudders. I'll also go to the lengths of detailing that would be stupid for something that will bounce around, but that's what I enjoy.

I can switch it so they all work as one. The way it's set up, as either outboard is controlled, the center motor will run the same as the fastest outboard. I can mix it so the center is always running faster (by percentage) than the fastest outboard to provide center thrust.

I really won't know until I get it wet. This way I have to throttle it with two sticks of the transmitter. It might end up being too hard to steer that way or just not fun, I don't know. I like a challenge, but I'm not heading to the lake to work... :hmmm

 

[moon puppy]

From what I've seen some RC guys are more into function than accurate. Gotta wonder if the rudders are enough to turn it once it gets up on plane. It might be to scale with the real one but that's not scaled water it'll be riding on.

Can't wait to see test runs. :captain

 

[sharkman]

Looks great Ausf!

I've done some training on Fast Rescue Craft with the Canadian Coast Guard on twin screw RHIB's and we were always taught to just trim the engines down for making high speed turns (whether that be for single engines or twins). Maybe it helps more for larger vessels to cut one of the outer props. Would be interested to find out the answer! I suspect the cut prop would create a lot of drag!

 

[lupanzer]

Nice!....

Luiz.

 

[Tankbuilder]

Got the guttywuts installed, I'm going to try to run it with three individual controls so I can steer with the motors. I have no idea how it works, my only experience with the idea was my friend was going for his master's license for multiple screws, so I guess there's a science to it over a single engine.

We'll see.

Turns will be a LOT slower when using just the center screw/prop. That's because there's no rudder directly behind it to deflect the water coming off that screw. I had that exact same problem with my 1/32 scale Lindberg PT-109 models with no center rudder when i ran it with just the center motor running.

Cheers

 

[moon puppy]

Looks great Ausf!

I've done some training on Fast Rescue Craft with the Canadian Coast Guard on twin screw RHIB's and we were always taught to just trim the engines down for making high speed turns (whether that be for single engines or twins). Maybe it helps more for larger vessels to cut one of the outer props. Would be interested to find out the answer! I suspect the cut prop would create a lot of drag!

That's what I was thinking about sharpening the turn, drag one side but what do I know, I haven't even been on a boat in years.

 

[Tankbuilder]

Looks great Ausf!

I've done some training on Fast Rescue Craft with the Canadian Coast Guard on twin screw RHIB's and we were always taught to just trim the engines down for making high speed turns (whether that be for single engines or twins). Maybe it helps more for larger vessels to cut one of the outer props. Would be interested to find out the answer! I suspect the cut prop would create a lot of drag!

That's what I was thinking about sharpening the turn, drag one side but what do I know, I haven't even been on a boat in years.

I have two radio-controlled Lindberg PT boats. I've run another one for many years. These models have the two wing props. i put a center prop and motor in one for two reasons. #1 was that the model on the center motor only would run for a lot longer time. #2 is that the center prop only was used in real life for idling along on patrol as that prop was deeper in the water than the wing props and thus didn't creat as much turbulence.

However, without a third center rudder the model turns VERY slowly on just that one motor. Here's why. All the props when running create streams of compacted water. That compacted water hits each of the wing rudders and that deflects/turns the boat. However since there is no center rudder there is no water hitting it to deflect/turn the boat. Another way of looking at it is that the two stream of compacted water striking the two wing rudders ADDS greatly to the turning effect of the rudders. There is very little additional affect on the rudders by the compacted stream of water from the center prop because it mostly passes between the two rudders.

At speed my PT boats turn extremely fast. When using just the center prop and the wing rudders the turning is extremely sluggish.

Cheers

 

[ausf]

Great info Tankbuilder, thanks!

I'm running three brushless on three separate ESCs and batteries. My thought was that if I hit LVC while on the water, I could use the at least one motor to get back if necessary. When you run your PTs, do you have the center prop runnng at all?

Originally I was thinking that having the center mixed in at 125% it would provide some stabilzing thrust, but maybe the best way is to drop it to less than the wing motors or cut it out altogether and just use it for a boost of speed.

Right now I have the Left motor on throttle, the right on elevator and the center on the rudder channel with the actual rudder as aileron. I mixed the center motor into both wings, so it goes equal with the fastest movng motor. But if it doesn't pose a drag risk, keeping it slow (or idle) until a burst is needed might work best for everything.