Tim Wiltse-RCU

Well it's not much to look at yet but after a little CAD time this is what I have so far. Sponsons will be balsa covered foam with .75oz fiberglass and WB poly-u, tub will be all balsa with ply for transom and hardwood motor mount, carbon booms. Most likely I will use a Hughey .098 flex cable and strut with my own rudder and strut brackets. Rudder will be offset on the rear sponson. Power will be via Norvel .061 will carbon fiber tuned pipe. Throttle servo will be a 5gram servo and HS-55 or HS-81 for the rudder. The more I do look at it I wonder if the front sponsons are alittle narrow...hummm.

Later,
Tim

Ron Olson

My Feedback: (1)

Interesting design but it looks like the tub and sponsons will be fighting each other aerodynamically. The front of the tub has lift in it and the sponsons seem to have some downforce built in. The sponsons don't appear to be too narrow as I've experimented with wide and narrow ones on my .12 'rigger. The record setting boats are really running narrow ones. You might want to use 1/64" ply instead of balsa. I went really light and used double-sided tape instead of glue to attach the wood to the foam. I got a 5-finger discount on some really good stuff from work. Use CA or epoxy at the joints and other critical areas.
Go with the metal gear servo for the rudder as the plastic one can't take any abuse.

Ron Olson

My Feedback: (1)

Tim, you might want to hold off on getting a Norvel for now. I was scanning through the latest issue of RCCA (I was bored) and ran across an article where several manfacturers are coming out with some really small buggies and trucks with maybe just what you're looking for. How about a Sirio .09? That's comnig out in a Kyosho Mini-Inferno. Team X-Ray has a slightly smaller .08 coming out for a NT18T

Tim Wiltse-RCU

Ron,

I believe the NT18 is using a Toki .05. They are gutless paper weights. I have not heard of the Sirio before. No worries on engines I have a pretty good stock of 1/2a sized mills. Heck I have 5 sitting on my desk as I type!!!

Later,
Tim

Ron Olson

My Feedback: (1)

I saw that some others are going to 1/2 A sized engines.
Sirio is pretty well-known around the car and truck circles. We might be seeing a tiny explosion in the neqar future if they start to take off.

jetpack

My Feedback: (1)

I am also into 1/2A motors and cannot find a prop other than the 1" Dumas plastic prop. Where else can I look? It would be nice to find a copper prop for this size.

Ron Olson

My Feedback: (1)

It's going to be tricky as the smallest Octura is an X-427 which is 1.06" in diameter. I don't know where the micro-hydro guys are getting theirs. A decent 1/2-A may be able to spin a 427 on a surface drive setup.

jetpack

My Feedback: (1)

Here's how Dumas compares to the Octura

Dumas: #3001 1" Dia. 1.25" Pitch LH

Octura: #X427 1.07" Dia. 1.498" Pitch LH

Both are 1/8" bores.

My boat plans for 1/2A are for a SK-Daddle, Jr. kit or the 18" Atlas Van Lines. There is also a set of plans from Boat Modeller for an electric balsa of the Atlas of a latter year which I think can become a good candidate if converted to ply.

The rigger would be fantastic I think with a hot .061 setup like you have plans for. I have a few 049/051 Cox motors I have gone through, even special carbs to try out.

My first outing with boats was with a free-running Dumas 1/2A Atlas Van Lines using a Cox 049TD, and the 10hp Merc fishing boat had a good time keeping up with it. It was all Dumas hardware and once planed out rode the prop and the motor would max out just perfect.

A metal prop would be great to play with, cutting it down or giving it a better pitch, as you try and get the speeds up. Plastic your pretty limited, and I'm sure nylon wouldn't be holding its shape too good if thinned, but on the plus side its (probably) a more accurate mold than a cast one. I bet the Octura will match the Norvel setup pretty well, even being a 1/16" larger diameter and might even want more. However the pitch is a 1/4" faster.

I haven't run any outriggers but watched them at the races and have a pretty good idea yours looks about right to me. I agree there might be some will be downforce issuses. Once on step the bow I think shouldn't need to be as high to handle any size chop on a pond.

I guess the best way to determine where the bow should reach is to wait till its balanced and running good, then see where it sits in the water. A bow only has to reach slightly above the waterline if it is expected to be self-planing. Drag vs. Lift/Downforce are always an issue to be chased.

The concern about narrow sponsons in this class is floatation at a reduced speed before it won't get back on step again. How slow do you want to go before it fails might be the right answer, say after a spin.

Looking at the motors on my desk I was checking out the AP Wasp, which basically has the same case as a Norvel. As with Cox engines there are no bearings and it brought up an old concern. I know most don't worry about it but it would be nice to install some type of bearing to get away from just a thrust washer between the prop driver and the case. Has anyone had ideas on this?

Will Sgarlat

Hey Tim,
I tried a couple home made .049 R/C boats and had some fun with them for sure. Here's the (really old) outrigger that started out using a Cox tee dee .061, then an OS .10. With the .061 it went straight pretty well and was really neat to watch, but it bogged down in the turns. I used micro radio equipment and made it as light as I reasonable could (1/64" ply over white foam sponsons, balsa tub), but I was not satisfied with the slowdown in speed when it turned.

It could be that I built a boat that was hard to turn, or that the .049/.061 power wasn't up to the task!

Maybe you can design your boat so it turns more easily than mine. Who can tell us how to make an outrigger turn well, with the least extra load on the engine?
Regards,
Will

BTW: the best part of this boat is the stand!

GiantScale

Interesting thread. I like your design. How far along with the project are you Tim?

How long is that rigger Will?

Another option are graupner props. I plan on a cut down 26mm. But a cut down 427 would probably be the easiest to mod.

Im concerned about the strength of these motors also. Marine engines have beefed up parts to handle jumping out of the water and back in etc.. These 1/2a engines might not like that. And if it ingests water it will be all over.

Any I idea on the flywheel size and weight? And where I can find a VA or AME engine.

Ron Olson

My Feedback: (1)

Dumas is the only place that I know of that has a flywheel that will fit on 1/2-A engines.

Tim Wiltse-RCU

GS,

Larry Driskill was the guy to get VA's from. He is out of them and I have been told that they are not making anymore. As for the Norvel AME's well that one is alittle tricky too. SIG is now the importer. The Norvel factory in Russia moved last year and they have been really slow getting engine sent back here to the states. There was word last year that Norvel was going to stop making the AME line of engines and just staying with the Big Mig line. There has since been word that SIG was able to get them to make more of the AME line. But still with that said most Hobby Shops that carry Norvel engine have a few in stock still you might just have to look alittle harder if you are looking for one.
I have not had alot of extra time lately so this project has not gotten much farther that more drawings and throwing around more ideas at myself. The more I think about it I do think I will go with a GZ .061 though. I will use the standard non tuned pipe version. It's still running in the mid to high 30,000rpm's so the power is still there just down some from the piped version. I will tweak the engine and mount either a Norvel, AP or CS/Brodak carb onto it. Pick up a flywheel from Dumas or just make one on my lathe myself. For the flex cable and strut I guess that should be easy to get from Hughy, Fullers or one of the other e-powered shops. Rudder and bracket again made by myself on my Milling machine, anodized to match the hull. Turn fin maybe carbon fiber?
Your sponsons that you posted over on the 1/2a plane forum look really nice! Keep us posted on the build and I'll do the same as I hope to get going on it in a couple more weeks.

LAter,
Tim

GiantScale

Sig was the only online dealer I could find. So its like shopping for antique's I see now. I need to just start asking who wants to sell one from there collection.

Are exhaust restricters or throttles easier to setup? If I find a good engine will you guys walk me through building one?

Larry Driskill gave me a contact for cyclons. Thanks. But $200[sm=tired.gif]

I can buy one of these for that money.
http://cgi.ebay.com/OS-12-TZ-Turbo-C...QQcmdZViewItem

I need to find a reasonable good used engine or settle for a AME .061 rc

Where do I find the GZ engines? Please?[8D]

Make some time Tim. Lets build these at the same time.

Tim Wiltse-RCU

GS,

You can get the GZ engines from Bill Huges, here is his contact info....

William Huges
113 N. Chase Ave.
Bartlett, IL 60103
[email protected]

630.736.6036

The GZ comes in both the .049 and .061 and piped and normal timed. Last I knew they are $85 for either one. I was going to get one myself last year for one of my many many plane projects but I ran out of time. My wife asked me the other day what I wanted for fathers day and I said nothing I could think of, well I think I know now
I think your right I need to dust off my work bench and finally get to work on this thing!!!

Later

GiantScale

William replied and confirmed he has the GZ engines and parts. I need to make a decision and order something. I wish someone would offer me a used engine with pipe so I would not need to break in and maybe even have a exhaust throttle already installed. Anyone? I Don't think I'm ready for building a exhaust throttle unless its simple. I don't have any experience with these small <.10 engines.

I'm sure you will enjoy this..

http://www.hydroworld.de/coppermine/...s.php?album=73

.09 AP engine. He starts it with a O-ring and an 12v 700series motor. I need to ask him some details. Watercooled. Marine flywheel and collet flex.

I will try a single channel approach I think. Throttle will be WOT while steering is neutral or right turn commands. Left turn commands will close the throttle. Then run it rich to limit speed the first times out.

Ron Olson

My Feedback: (1)

Tim, back to your first posting. It will help if you do take the sponsons wider for more stability in what will be considered rough water with a small 'rigger. The Japanese do this even with their larger ones as they do run in worse stuff than what we normally do.

On the Cox engines, they did have an exhaust throttle setup in 2 forms that I knew of and one had an arm long enough to make hooking up linkage to a lot easier. I used to have 2 of those but sold them to someone who needed them as they must be hard to come by.

jetpack

My Feedback: (1)

Just a side note on throttles. A VA throttle will thread into a TD housing with just a little help from teflon tape to take up the air gap. Seems to be the same pitch, just smaller... the throat seems small though on those. I haven't tested.

Tarno carbs are bigger, but less common...good throttle response from them though.

Cox throttle sleeves...be careful the type you buy, dont buy them loose they are not all the same size. Get one thats on its original cylinder then your sure of a match up.

GiantScale

Any progress Tim?

Im pretty much done with my hull. And I need to order a engine. Im thinkin a wire drive might be the lightest and easiest to fabricate. How thick of music wire do you think it would take? I have some .032 which I might try.

Tim Wiltse-RCU

GS,

No real new progress on my end. I am trying to get some other projects out of the way before I get started to far on another one. Thinking about the problem for a throttle for the GZ engine. There are a couple of different carbs out there that may work. The AP carb is around $15 and the Brodak/CS carb is a whole $5.00 I think. Both are said to work well on their stock engines and I am sure they could be fitted to the GZ.
I think the music wire idea would be a bad idea for the drive shaft. These engines while small put out a heck of alot of power. A .098 flexcable would do just fine. The stumbling blocks are going to be fitting together a hardware package that will work well together i.e. strut, shaft, collet, prop and flywheel. I am going to have to buy the engine first before I do any work on a hull so I know what I have to start with and then start machining from there.

Your hull looks really nice!

LAter,
Tim

GiantScale

Thanks Tim. Did you notice the breakaway wooden waterpickup rudder?

The drive line and engine is what I cant decide yet. I wrote Bill Hughes
about the GZ. His response was this..

" It is NOT a Boat Engine. It was designed for use in a Model Airplane. A Control Line Speed
Airplane. It has shown that it does not Throttle down very well." He then went on to say it was used in a RC tractor with a larger cooling head he sent a pic of.[sm=confused.gif]

Im disappointed because the GZ prop screw is a 4M (instead of the 3M norvel) from what Bill said. Which could be replaced with 4M threaded rod. Then lathe the hole on the flywheel to 4M and attach with nut. The threaded rod after the flywheel nut could be turned to 1/8" to mount a set screw octura .098-1/8" flex hex.

Now what? Back to the norvels and deal with the 3M screw?

Or still go with the GZ engine despite what Bill said? He sent me a price list which shows a tuned pipe for $25. Why wont it work on the normal timed engines? He also has a heat sink head available. Why would that be available if the engine was strictly for airplanes?

And others have said use a exhaust baffle on CL engines. Which would work better? The carb or baffle?[sm=confused.gif]

1993fordprobe

I have beeenlooking for plans for a .45 to .90 rigger, it seems like alot of people responding to this thread may be able to help. heck, i would even pay someone to design me one, maybe a twin .45. If any one can help me it would be greatly appreciated. thanks.

Oh, good job on the plans

GiantScale

http://www.firefighterboats.com

Tom has "tested and proven" plans.

I bet his new gas rigger would work with a .90