Stingray Build

[RCnut]

Lol Is that rain as well? Cheers David, I am a Plane flyer and have a fondness for banking and yanking. I cant do much more till The WTC is sorted so with that in mind I will sort out a set of parts in the next couple of weeks and send the whole kit and kabboodle to you.

[He Who Shall Not Be Named]

Lol Is that rain as well? Cheers David, I am a Plane flyer and have a fondness for banking and yanking. I cant do much more till The WTC is sorted so with that in mind I will sort out a set of parts in the next couple of weeks and send the whole kit and kabboodle to you.

Excellent. Then your transition from airplane to this beast is a simple one: you will fly STINGRAY around -- just a slower airplane.

If you do make the stern horizontal stabilizers working control surfaces, gang them to the linkage that operates the gimbaled PJ nozzle about the pitch axis. That would insure pitch control even if you throttle back on the PJ.

When I get the kit I'll size a SubDriver for it, outfit it, get my STINGRAY working (control surface linkages as well as the scavenging type ballast system that'll be used to de-water the hull) thenI will freeze the design. I then build up and outfit (less receiver -- you UK types have your own legal bands that I don't have receivers tuned to) a SubDriver for you, as well as the mechanisms that will employ your PJ hull mounted intake portion to take a suction on interior water to get the STINGRAY to a high freeboard when surfaced, and send it all to you in exchange for the STINGRAY kit.

Can't wait. You have created a beautiful model there and I want to do it justice with the mechanisms needed to animate it. I'll need to know what motor, ESC, and battery (with dimensions) you recommend for that PJ.


I remain amazed at the speed and quality of your work!

Me? I like making weird things work well in the water. Below is the Rick Teskey kit r/c'ed.


David

[RCnut]

Ok Heres the first thing, The kehrer I was going to send is junk as they have upgraded it anyway. this is what you will need.

http://www.jet-drive.de/index.php?page=shop.product_details&flypage=shop.flypage&product_id=9&category_id=4&manufacturer_id=0&option=com_virtuemart&Itemid=17&lang=en

And this is what I had to do to make it conform. So You would have to order a spare Stator box as well.

[He Who Shall Not Be Named]

Will do. I'll get that unit and take it from there.

I also realize, after examining that ad photo of the pump-jet nozzle, that the nozzle is not gimbaled -- it only provides for one-axis pointing of the stream. Yaw only. I'll have to work up a two-axis gimbaled nozzle that will fit over the stator tube and not get in the way of your RateMaster drive wheels. That will happened when I get the parts in hand and can size things to work within the geometry presented.

Below are shots of the two-axis PJ I worked up to steer and dive the DeBoer Concept-2 SEAVIEW model:

[Captain Scifi]

That's an interesting Seaview model, looks like the next evolution, I like it.

What effect do you think the cabin wings will have on the dynamics of the model when submerged?

I would like to get your jet unit David but can't find it in the store, is it still available?

[He Who Shall Not Be Named]

That's an interesting Seaview model, looks like the next evolution, I like it.

What effect do you think the cabin wings will have on the dynamics of the model when submerged?

I would like to get your jet unit David but can't find it in the store, is it still available?

Yeah, I'm worried about those two big dorsal fins too, Captain. They look to have positive incidence to the boats longitudinal centerline. They're very close to the boats CG, a bit aft of it, so the pitching moment is short and they won't be much consequence to the dynamics of the thing. But, man! the drag they will introduce!

What 'jet unit'. Be specific. And what's the application. I'll fix you up.

David

[Captain Scifi]

A Stingray capable one please, as I can't find your listing for them I can't answer this specifically. I am trusting you will make a WTC or a modified version thereof and a custom thruster unit to match. It's this "best fit" recommendation I am really after as a place to start.

[He Who Shall Not Be Named]

A Stingray capable one please, as I can't find your listing for them I can't answer this specifically. I am trusting you will make a WTC or a modified version thereof and a custom thruster unit to match. It's this "best fit" recommendation I am really after as a place to start.

Bernie,

I'll be going with the PJ Mamas recommends -- the only modification in that department will be a customized gimbaled nozzle as the commercial one is only able to swing in the yaw axis -- we need one that will throw water about the pitch and yaw axis.

I will indeed develop a specialized WTC/SubDriver for this particular model. No ballast tank and it will be outfitted with the ESC and motor recommended by Mamas. Once I get mine going I send one to Mamas in compensation for the STINGRAY kit, then, with the design frozen I'll produce them commercially.

Back to the pump-jet: I will be making an 'add-on' device that taps into the suction side of the PJ -- this to de-water the models hull using the PJ as the 'pump'. More on that here and in Cabal Reports as work gets underway.

Oh ... a thought for Mamas:


I'm thinking a separate, well geared, smaller motor to work the RateMaster. It has its own ESC which is controlled in parallel with the input to the PJ's ESC. So, two motor outputs from the SD's motor-bulkhead: one from the brushless kick-ass motor to the PJ, and a second output driving your three-wheel RateMaster rotating gizmo. Whacha think, oh Wizard of all things Anderson?

David

[Captain Scifi]

Bernie,

I'll be going with the PJ Mamas recommends -- the only modification in that department will be a customized gimbaled nozzle as the commercial one is only able to swing in the yaw axis -- we need one that will throw water about the pitch and yaw axis.

Hi David, that's sensible, he is an expert fettler when it comes to making it go/stop/left/right/up/down and backwards.

I will indeed develop a specialized WTC/SubDriver for this particular model. No ballast tank and it will be outfitted with the ESC and motor recommended by Mamas. Once I get mine going I send one to Mamas in compensation for the STINGRAY kit, then, with the design frozen I'll produce them commercially.

Ok, I'll wait to see what develops and jump in when the hard work is done.... :biggrin:

Back to the pump-jet: I will be making an 'add-on' device that taps into the suction side of the PJ -- this to de-water the models hull using the PJ as the 'pump'. More on that here and in Cabal Reports as work gets underway.

Oh ... a thought for Mamas:


I'm thinking a separate, well geared, smaller motor to work the RateMaster. It has its own ESC which is controlled in parallel with the input to the PJ's ESC. So, two motor outputs from the SD's motor-bulkhead: one from the brushless kick-ass motor to the PJ, and a second output driving your three-wheel RateMaster rotating gizmo. Whacha think, oh Wizard of all things Anderson?

David

[RCnut]

Hi Guys!

Back from the seaside and ready to start fettling, lol. David, I have been thinking along the same lines for the ratemaster motor and to that end got hold of a Graupner item but the ratio is still to high. It needs a very low rpm and high torque to spin the Rt at a reasonable RPM. I did consider a High power disabled servo but its configuration would make fitting awkward. I think you need to have the Stingray asap to be able to solve these and many other questions Oh wizard of all things Submarine type stuff.

[He Who Shall Not Be Named]

Flattery will get you everywhere, Mamas!

Yeah, we yank the pot out of a 'standard' sized servo, put a heat sink on it's 'amplifier', wire it in parallel with the main motor ESC and we're in business if I can raft the servo above the main motor. If that turns too quick/not enough torque we simply use one of those old, nasty Astro-Flight motor-planetary gear units (the stacked gears permit a zillion-to-one ratio if we need it) and a little MTronik's ESC to drive it. We'll make this beast work!

Get me that kit, I'll size the largest SD diameter that will fit and perform my magic tricks.

I'm stoked! Break out the Bongo-Drums!

David

[RCnut]

David

Something for you to answer, How good are sealed bearings for keeping out water? The spin gizmo has 3 sets of 2 bearings holding the mandrels. I was thinking of using brass bushings instead. The RM does not need a high RPM so I would have thought this would be an acceptable option......?

[He Who Shall Not Be Named]

David

Something for you to answer, How good are sealed bearings for keeping out water? The spin gizmo has 3 sets of 2 bearings holding the mandrels. I was thinking of using brass bushings instead. The RM does not need a high RPM so I would have thought this would be an acceptable option......?

So called 'sealed' bearings, in water, aren't!

The seal is a keeper of factory injected grease, it is not a water barrier -- the sealing element actually works against us. Here's how:

The bearing spends most of its life out of the water, enjoying an atmosphere that has a significant fraction of oxygen in it. Yes, yes, they say, stainless steel, but there's always a whiff of iron in there (intentional or not). Your bearing spends a very small fraction of its life in fresh water, just long enough for the water to get into the seal, soaking the balls/rollers and races. And when you pull the thing out of the water, the seal does a great job holding the water against all the metal parts, where the water starts working with its good buddy, Oxygen, to eat the bearing elements alive! Put unlike metals nearby and Mr. Ion joins the pig-pile!

Go with oil impregnated brass bushings. We're not launching the frig'n Space Shuttle here!

David

[RCnut]

So called 'sealed' bearings, in water, aren't!

The seal is a keeper of factory injected grease, it is not a water barrier -- the sealing element actually works against us. Here's how:

The bearing spends most of its life out of the water, enjoying an atmosphere that has a significant fraction of oxygen in it. Yes, yes, they say, stainless steel, but there's always a whiff of iron in there (intentional or not). Your bearing spends a very small fraction of its life in fresh water, just long enough for the water to get into the seal, soaking the balls/rollers and races. And when you pull the thing out of the water, the seal does a great job holding the water against all the metal parts, where the water starts working with its good buddy, Oxygen, to eat the bearing elements alive! Put unlike metals nearby and Mr. Ion joins the pig-pile!

Go with oil impregnated brass bushings. We're not launching the frig'n Space Shuttle here!

David

Thought so and will do.

[RCnut]

The RM housing rings as supplied will need to be glued together with solvent weld. Three Blind nuts will need to be fixed to the back so the modular part, whatever its function can be inserted using three screws. I heated up the blind nuts and pulled them into place and reinforcing with Superglue. As you can see quite a neat little affair. Next the jet installation.