Let's design a model for one of our Cox engines.

944_Jim wrote:Roddie,
I feel like I haven't seen anything from you in a while. I think I checked your profile a couple of weeks ago, and noted you hadn't posted in a long minute.
It makes me feel good to see you are alive and kicking!

Regarding your request, I dreamed of doing a twin-screw deep vee when I was a kid. Dumas still had their hardware packages for the 1/2A engines. I think I looked a while back, but none of their IC kits were on the website. All of the smaller boats were electric drive.

Hi Jim. Thanks for your concern and comments. I miss being here and posting regularly like I had been. It's all good with me though. I'm taking many things in stride these days.

Regarding "your" request.. why not design a twin-screw deep vee? Aqua-Craft has produced marine-drives small enough to be adapted to Cox 1/2A glow engines. You may need to do some silver-soldering.. and source a flywheel. Sterling models made a flywheel for the Cox .049. Dumas's flywheel for Cox engines.. has a center-bore for a 6-32 machine-screw. This made it possible to run .09 Medallion or Tee Dee engines in their kit offerings. It's vitally important to bush that bore, if you're running the smaller diameter 5-40 machine-screw utilized by the Cox .049 engines.

You may already know most of what I stated.. but it's always satisfying to design and build a "one-off" model. If it performs its function.. even if substandard; it can still be looked at as a success.

I've also been into powering a small speedboat with a Cox 1/2A engine... I wanted the Dumas Kit of a little runabout that they used to offer. It's been out of production for a long time. It's called the "Half-Pint".. and I've wanted to build one for 2ch. RC with Cox .049 power.. ever since the RC electronics entered the "nano" state of function.





It's just such a cool little boat..

Roddie, I've always thought there should be a CEF Special CL airplane and a CEF Special R/C airplane.  Designs that could be built for .049 engines, and scaled up to a .15 size or scaled down to a .010 size.  It wouldn't be hard.  Just need to get an idea of what it should look like.  I think they should be simple designs.  Something that anyone could build.  Nothing complicated or a hot rod that's hard to fly.  No multi-channel beasts, just a 2- or 3-channel RC plane for easy flying, and an easy to fly CL plane that will do roundy-roundy and a few loops and easy eights thrown in there for good measure.  I've had all kinds of ideas, but Jacob should be the one to decide what one should look like, if he's interested.

The Up-Scaled Mark

Roddie,  that Dumas Half Pint kit shows as available on the Dumas website:

https://www.dumasproducts.com/?product=half-pint-cabin-cruiser-kit-1209


They also sell the running hardware kit for the .049 engines. $35.00 seems quite reasonable:

https://www.dumasproducts.com/?product=running-hardware-kit-2314-for-1209-1410-1411-1422


I have a running gear set somewhere for a 1/2A boat.  I think it's a Sterling kit.  I got it in a parts lot and think that it's all there, but I haven't tried to put it all together to see.  I'll add the Half Pint to the list in my head for uses for the drive.  But there's no local boating group around here, and I don't know that people'd like the sound of a 1/2A screamer if I took it to the local park.

The Not All There Mark

batjac wrote:Roddie,  that Dumas Half Pint kit shows as available on the Dumas website:

https://www.dumasproducts.com/?product=half-pint-cabin-cruiser-kit-1209


They also sell the running hardware kit for the .049 engines.  $35.00 seems quite reasonable:

https://www.dumasproducts.com/?product=running-hardware-kit-2314-for-1209-1410-1411-1422


I have a running gear set somewhere for a 1/2A boat.  I think it's a Sterling kit.  I got it in a parts lot and think that it's all there, but I haven't tried to put it all together to see.  I'll add the Half Pint to the list in my head for uses for the drive.  But there's no local boating group around here, and I don't know that people'd like the sound of a 1/2A screamer if I took it to the local park.

The Not All There Mark

It's GREAT to hear from you Mark! Thanks for researching the Dumas 1/2 Pint model boat. I'll have to take a look. Oooo just did.. $55.00 I need to ask myself; what's the allure? I can answer right away.. in that it's the "cabin".

Here's a photo of my kinda' boat...



I always looked at that little Dumas boat as a candidate for a Vintage Century 19' runabout with a big-block FOMOCO 390-V8 inboard drive. A big-boy lake-boat. Pull 4 skiers out of the water in a heartbeat.

batjac wrote:
The Not All There Mark

Every time unique, always in context...I don't know how you find the different ways. You slay me, Mark!

I'm definitely not all there. I like to spread myself out a bit..

Model boats to be conventionally powered by our Cox engines, present some challenges. Ever since I was a child, I've always loved the idea of small-scale modelling.. so nothing seems "undoable" to me.

Cox developed and offered the "Sea Bee". A true inboard-drive "lake-style" runabout for pools and small ponds.

944_Jim wrote:

batjac wrote:
The Not All There Mark

Every time unique, always in context...I don't know how you find the different ways. You slay me, Mark!

What can I say, I was always a Peter MacNichol fan...

The Slayer Mark

So what we got going on over here ? Boat/car/plane ??

Eric,
I took it to mean "what would build if you designed your own ____."
Insent your dream on the line.

I was given a boat hull when I was first playing with balsa. This boat was the impetus to learning what dope was. I couldn't afford the drive hardware, nor had any tools for fashioning an engine mount. It was never finished and tossed.

That's why I selected "boat."

944_Jim wrote:Eric,
I took it to mean "what would you build if you designed your own ____."
Insert your dream on the line.

I was given a boat hull when I was first playing with balsa. This boat was the impetus to learning what dope was. I couldn't afford the drive hardware, nor had any tools for fashioning an engine mount. It was never finished and tossed.

That's why I selected "boat."

Yes.. That is what I meant. It's been a while since we had some mutual participation by our members. People have flown "shop-rags" (free flight).... with their Cox engines. While I don't recommend that.. it does imply what can be done with minimum time/effort and monetary investment.

Living in USA/New England?Rhode Island; I see a distinct 4-season change with warm Summers, cold Winters.. and wonderful changes of Spring and Fall. That stated; there is usually freezing temperatures in the Winter. There may not be much snow.. but usually there is ice on the ponds. I've often thought about building an "Ice Yacht", powered by a Cox engine with an aero-propeller.. and "blades" to glide over the ice.

Half the fun for "me".. is thinking the design through before I start gathering the items needed to bring a model to fruition. Take the "blades" for the aforementioned ice-yacht for instance. I envision some 1/2" (12mm) aluminum angle-stock (90 degree) to serve as both; blade-runners as well as frame-connectors and possibly a pylon for mounting the engine. I'd want the option to remotely steer the model, which would only require a single RC channel to either actuate an air-rudder.. or possibly a "pivoting-frame" which might prove superior to the former.. and depending on the design; allow for easy disassembly into two pieces for storage.

That's just an idea at this point.. and not something that we all could realize.. due to our members varying regions of climate.. but sometimes it can "get the creativity juices flowing.." when reading about someone else's ideas. You know?

OK Got it , get the juice's flowing ! I been thinking Twin something looking at some kits

@roddie does your excellent design include Barbaralla? :lol!

Yabby

Ok. So it seems a few would tend to go the boat route, which is what I just thought as well. However, I was thinking very unconventional. Not even sure it would 'fly' so to speak. Not meaning a plane that would fly, but rather a boat with a low mounted engine in a pusher configuration that would utilize 1/2 or even 1/3 of the propeller in the water for propulsion. Of course, whatever is above the water would also help, but thinking it would produce a 'rooster-tail' of sorts......

Or is this just a plain old stupid thought.....

NEW222 wrote:Ok. So it seems a few would tend to go the boat route, which is what I just thought as well. However, I was thinking very unconventional. Not even sure it would 'fly' so to speak. Not meaning a plane that would fly, but rather a boat with a low mounted engine in a pusher configuration that would utilize 1/2 or even 1/3 of the propeller in the water for propulsion. Of course, whatever is above the water would also help, but thinking it would produce a 'rooster-tail' of sorts......

Or is this just a plain old stupid thought.....

Hi Chancey! We would not want an aero-propeller to dip into standing-water while spinning. There are two reasons that come to mind; the first being that the prop could "shatter".. which is a safety issue. The second reason is that the model would experience a pronounced "paddle-wheeling" effect. This effect is there; albeit to a lesser degree, when running a conventional marine prop. The boat will turn a tighter radius when steered in the direction in which the prop is scooping water. There is generally some rudder-trim applied. to compensate for this, in order for the boat to maintain a straight course while underway. Steerable marine out-drives are no exception.

roddie wrote:

NEW222 wrote:Ok. So it seems a few would tend to go the boat route, which is what I just thought as well. However, I was thinking very unconventional. Not even sure it would 'fly' so to speak. Not meaning a plane that would fly, but rather a boat with a low mounted engine in a pusher configuration that would utilize 1/2 or even 1/3 of the propeller in the water for propulsion. Of course, whatever is above the water would also help, but thinking it would produce a 'rooster-tail' of sorts......

Or is this just a plain old stupid thought.....

Hi Chancey! We would not want an aero-propeller to dip into standing-water while spinning. There are two reasons that come to mind; the first being that the prop could "shatter".. which is a safety issue. The second reason is that the model would experience a pronounced "paddle-wheeling" effect. This effect is there; albeit to a lesser degree, when running a conventional marine prop. The boat will turn a tighter radius when steered in the direction in which the prop is scooping water. There is generally some rudder-trim applied. to compensate for this, in order for the boat to maintain a straight course while underway. Steerable marine out-drives are no exception.  

See, I knew it was a bad idea! Lol.

NEW222 wrote:Ok. So it seems a few would tend to go the boat route, which is what I just thought as well. However, I was thinking very unconventional. Not even sure it would 'fly' so to speak. Not meaning a plane that would fly, but rather a boat with a low mounted engine in a pusher configuration that would utilize 1/2 or even 1/3 of the propeller in the water for propulsion. Of course, whatever is above the water would also help, but thinking it would produce a 'rooster-tail' of sorts......

Or is this just a plain old stupid thought.....

I love the thought of an "air-boat" design Chancey. Such a design IMO would need to out-perform (in terms of straight-ahead speed..) any other model of equal scope, that's been previously done.

There are of course; varying classes for vessels here. "Free-sail", "Tethered" and "Radio-Control". One aspect that could equally influence "all" classes, is hull-design combined with hydro and aerodynamics.

Lets look at a hull-design approach, aimed at utilizing a single Cox aero-configured engine. I would personally try to source a lightweight/water-resistant material for the hull.. which would be user-friendly to common adhesives and fabrication.

As you mentioned  mount the engine as low as possible.. without the propeller striking the water. Make the engine-mounting "pitch-adjustable". Deflecting the engine's prop-wash "downward" will create lift. If your design is of a "catamaran" style hull.. you could vector that thrust down at the open water between the two outriggers.. to create lift.

You would need to optimize the C of G just like an aircraft.. but that's what makes it really interesting and worth the effort.

Chancey,
Twist your idea a bit. Get the engine up front, above water, and build a water plane. I've even seen where the machine is built like a hydroplane flying on a cushion of air in the tunnel through the boat.

https://youtu.be/MYZgUZgS24o
https://www.popularmechanics.com/military/aviation/news/a27927/russia-is-working-on-a-new-sea-monster/

Hi All,
Back in the 1970s any information was gathered via Model Airplane Magazines.
I had some Dumas/gear/ props I hooked up to a Cox.049. With a big Heatsink.
Priority was saving the then new R/C control.
Allot of swimming in the 16mile creek to get it back.
Dismal failure.
Next Model Mag had a design for a 'Florida Swamp Buggy'.
In two weeks, we had three going.
Great fun.
Your Friend,
Dave

Please note that I edited the 1st post today by adding paragraph 2..

(read it here)