robot797

i am still fixing my boat
(hull)

and when i am done i am boating

with a video

R.J. West

ROBOT!

There you are, we missed you. How long are those winters over there? Its 73 degrees over where I'm at already, shorts N' sandals
Whats wrong with your boat?

robot797

well lets say i need a batery coffer

and yes the winters are long here it is freezing 1.5 degrees (celciuc)
and we are getting more snow soon

so it is gonna take a month or 2

we have a saying here
april doet wat ie wil
april does what he likes

it means that we can have a blizzard in april of 30 degres

it depends on the year

Will Sgarlat

This isn't A Dumas and there's an OS .15 in it now, but this is how it looked right off the draftboard with a Tee dee .051 in it.
Are we strictly Dumas boats, or are 1/2A powered boats in general fair game?

Pond Skipper

Your golden if your using 1/2A range of power.  =)  Do you have any vid of it running on the cox engine?

Pond Skipper

I got lucky and found on ebay a aluminum carb body for my Tee Dee 20, unlike the one I bought for the 051 this one fit like a glove. Heres a pic.

robot797

i did not have time to finish my cox boat
i could not work on it cus i was buzzy with a turbine engine
i had to write the software and i am just halfway (my atmega368P got fryed)

in about 2 weeks i will finish it and make it sail

i also found a cox 049 (black widdow) r/c mini i wil post some pictures (tonight) for the heck of it

and that is using my boat equipment this last week


that was it

jetpack

My Feedback: (1)

I bought a bunch of mahogany veneer for my boat projects and going to use a balsa/mahogany composite to build my own Drag N Fly Jr 18".

I have it drawn out but I cant get it to print to the scale I want with my printer its driving me nuts. I'm about to surrender to kinko's on this one instead of trying to tile print it.

It's a hydroplane but almost a tunnelhull the way the tail is built on it.

Will has the right idea about it using a tunnelhull. Thats a nice boat, Will! Welcome! [8D]

The problem I had with my first 1/2A boat (Atlas Van Lines hydro) was not being able to adjust the thrust and height of the prop and that's a huge play area going with these motors because there's not a big window for power.

If I'm able to get a Drag N Fly scaled down and built nice and light with an adjustable strut, I have lots of props and engines to play with to get all the speed possible with the Cox.

One thing I'm missing which would help a bunch is a micro RX with a small lipo. Right now all I have is a 4 cell AAA pack and standard reciever.

I am still working on restoring a bunch of vintage power benchtop tools to build my boats with, but I picked up an old drafting machine that will help clean up and make accurate my boat tracings.

Me having my own woodshop has been super slow getting here but I'm at the point of not wanting to work on anything until I get a shop this time so hang with me.[]

Skipper, I bought those aluminum intake housings when they came out and I had the same trouble with it being undersize like you did. I used Copper Cream as a lapping compound and my oldest TeeDee case I had to size it.

I wrote him a note and also provided a batch of measurements for him to have of my cases.

I am glad I bought one that wasn't anodized I would have been really disappointed having to hurt the anodizing if it was. They are nice items over the plastic I think. Your small .020 TeeDee rig is looking serious.

I remember owning a TD .020 early in the control line days I've had and they are amazing little power packages capable of some really high revs.

Pond Skipper

Thank you Jetpack, looks like your info may have prompted him to fine tune his work as the 020 carb housing fit perfect. I was fully ready  to have to labor the new part to fit. I need a lil more fly wheel weight for the 020. the one on there right now is only half the weight needed. I have dug around to no avail for something small. The only thing I can do now is a washer stack / have a custom one made or grind down a 049 fly wheel.

Will Sgarlat

Wow Jetpack, that is an impressive bunch of Cox bins! You are rich with parts! I visit this thread regularly cause I love Cox engines and little boats. I'm looking forward to seeing your progress with your 1/2A hydro. Thanks for the complement on my yellow boat. I think it (was) a sweet little thing. I have no vids of it running, but the power was marginal: it went great in the straights, but bogged down in the corners. I tried all sorts of adjustments to prop height and thrust angle, I also added lead weights to the nose to change the balance, but the best I could get was...marginal. I wonder if I did a new version and used a small Lipo like you suggest, it might go a whole lot better! The outline of the bottom of the sponsons has a "rocker" at the stern like a Dumas Sprint tunnel hull; it's not a straight line from the middle of the bottom to the back end. I think if it was straight it might run with a flatter attitude. These kinds of details may sound dry and boring, but changes to one design element can make the difference between a great-running boat and one that "goes pretty well".

Pond Skipper

Based on the pic of the yellow tunnel hull you was over propped. The lower pitched dumas props made for  1/2A will work better in the turns and the lil motor will be able to breath down the straights.

R.J. West

Lets keep it alive!

When I had my Dumas Miss Unlimited kit I did trace all the parts onto paper for the purpose of creating more hulls in the future.
I plan on doinga 3/32balsa laminated with 1/64 ply version of the hull next which after I built the 18" Atlas van lines, Ilearned alot about these small Cox .049 powered hulls.

jetpack

My Feedback: (1)

Okay!

Not much, but I was in Ace Hardware tonight for restoration screws for my woodworking tools I'm doing and looked at aluminum shapes in the stock rack.

I've been meaning to look at the size and thickness they have of C channel to duplicate the stock Dumas rudder and water pickup bracket of their standard hardware for it to fit the Drag N' Fly Jr. project.

I can get the right size of channel to fit, but now the problem is stuffing it with a rudder post that is light but large enough in diameter to work with.

The regular size posts are solid 3/16th inch steel rod that is sawn to accept a brass rudder plate that gets soldered to it.

I thought about staying with just a music wire setup which probably is the lightest way to go and would take just two small hole drilled through the channel, but it would be nice to have a better setup with bushings for a better fit and no metal to metal for the radio interference problem it can give.

Pond Skipper

I have located a local club where I can run nitro powered boatslegally and will be pursuing 2 designs. Tooo bad no one has a video that would really help juice up this thread and get more people on board wanting to make something run on 1/2 A power.

R.J. West

In my next project I think you might like what i have in mind for it. I also bought some U channel aluminum stock to use as a rudder bracket, however I bought mine first so you cant say i copied off of you. I chose to use 3/8 X 1/2 channel. Its soft stuff and easy to cut down with a razor saw and dremel. I would just go for brass tube as a bushing for the wire that your rudder is soldier on to and keep it simple and not over think it..

robot797

i am almost done

but somone is trowing my vome tape

i cant seel the battery compartment of my boat

rcrob625

My Feedback: (1)

HELLO i am new to boating and i would love to make a small but fast nitro boat. i was looking at a dumas 10 deep vee with running a .12 car motor air cooled with a pipe. something i can run in the mangroves with 1" waves. i was wondering i i can make the boat with a surface running prop and turn fins ect like the big boys down here in the keys. any help would be nice. i am on kind of a limited budget and i have tonnes of 10th scale nitro car stuff so i was thinking i would like to stay small. more fun and lots cheaper but it is hard to find parts and ect to fit. any links or tips would be a great help! thank you

R.J. West

Thats a cool boat and its also designed for 2 channel radio control as well! I dont think you'll be happy with a .12 engine as it was done before on a similar hull, a ski daddle jr powered by a .15. That particular boat couldnt be run at more than 1/2 throttle without spinning out and going anywhere but straight. I would suggest finding a Cox medallion .09 r/c. Dumas still sells the running hardware for either a .049 & another kit for use with a .09. The hardware kit for that boat is useable, but you can also find other more user friendly hardware to use instead, however you are going to need the flywheel from dumas. Good luck and welcome to the hobby!

Tee Bee

I just stumbled on this neat thread after finishing my Dumas Lil Swamp Buggy. I know it's an airboat but thought I'd post up anyway. I'll be sure to go back and read this one more thoroughly. I'm mostly an airplane guy but am heavily invested in Cox engines and parts so this peaks my interest.

Pond Skipper

Hey Tee Bee, looks like you did a great job on your air boat how does it run?Do you have any vid ? Anything 1/2A boat wise will work in this thread = )and its a one of akind the only thread Iknow of that discuses 1/2A boats.There is a local pond near methat is full of the green goo a swamp boat would be perfect for that. As it isIhave to drive further for the water propped boats.

robot797

well guys great news

my boat runs great
the only problem i have now is the comming lose/of of the fuel line

and the firsth run has no video
the next run (this week) has a video

nice boat "tee bee"
is the piston/cilinder a psi or a normal?

Pond Skipper

Trick to keep the fuel line on is cut a small piece of line and open it up with a pair of needle nose pliers and slip it over the end of the fuel line that goes to the nipple of the engine carb.  This will cause the line to bite down better over the carb nipple. Another trick is thin wire, such as from the wire tie that is used to hold loafs of bread.  Wire that thin can be placed around the fuel line once its on the carb nipple, just twist it till it's snug. And congradulations!!! Look forward to seeing your vid wooot

robot797

i will try that when i come home
and i finaly fount the fuel for my diesel cox engine

i only need a boat or a plant to mount the engine on
in the worst case i am goeing to mount it on a kyosho mini cooper

if pictures are needed i wil post them

jetpack

My Feedback: (1)

Skipper and all, I wanted to check in and let everyone know there is a flywheel I found that seems to be manufactured at one time. It's more of a starting pulley for an .049 than it is a flywheel for an .020 but I thought it would be something to try out. Skipper mentioned having trouble with finding the right flywheel and wondering if this would be it.

It's made of aluminum, and about the same size as the back of the tank. The hole is drilled 1/8th though so that would have to be bushed with tubing or tapped in to run true. I have a couple of them that came with the deal.

R.J.West

Soooo. Basically what your saying is you just wanted to keep the thread alive, right?

I'm currently refinishing my little dumas Ace sailboat which may or may not quailify as a 1/2A boat but it is a 18" Dumas.....
hey Jet when you get one of your boats finished I'l challenge you to a race to the other side of the pond against my Ace sloop, whadda say?