Re: R/C airboats

PV Pilot Fri Sep 07, 2012 11:35 am

microflitedude wrote:Would you mind if I tested it first before pulling the RC assembly off? I love throttled engines, and am more relaxed when running them vs wide open the whole time. Noise is also an issue where I live. But if it won't get up on plane then I guess I have no choice.

I switched out the servo plugs on the receiver and it worked. They were plugged in the right way, doesn't make sense. (Futaba connectors won't go in the wrong way)

It was too late though, I had already chopped up the harness again. I am now using a switch like the one you linked to. I ordered a silicone boot to waterproof it.

How/where would you put the charge lead for the RX battery? I don't want to take the screws out after every session to recharge it.

In October I'll take it to my club's float fly.

It's your boat Matt. try it the way it is if you like. Nothing I put down is a set-in-stone orientation, just putting my experience out there for you. I like the throttled stuff as well. I don't mean to sound condecending or teacher-ish in my posts, but I feel they come off that way sometimes.

With that weight so far back, you can add washers on the top motor mounting lugs to change the thrust angle to force the nose of the boat down sightly to see if it will jump on plane.

Sounds like you might have a socket or pin connection in the tiny little servo connection plugs that isn't happy or is moving in the plug end when you shove the plug together with another or onto the reciever pins. Those are very delicate connections, try not to force anything if possible, make sure the pins and sockets line up correctly and the pin and socket wires stay latched in there little plastic plugs for connection. If you get a rudder glitch or throttle glitch, it is usually because those are loose or have a bad connection somewhere in the system. I custom build all of my servo connections and wire lengths with the available pin/socket/plug kits, so I have put a few of those together over the years.

It's a pain to remove the hatch screws every time to recharge. Socket head screws and a Allen head ball driver eventually can turn into a friend to speed that process up. You can bore a hole thru the hatch of the boat and have your charge wire protrude, just make sure to water seal around the wires that exit, and sufficently seal that plug end with a balloon chunk and ribber bands wrapped tightly. It's better to have that end down inside the radio compartment, but it can be made to work outside considering all options for a short circut. A few pieces of paper towel cut to fit down inside the radio compartment to soak up any water that might intrude,,it's also a good indicator of where you might have a leak if any. If you see dry paper towels down in there after pulling the hatch after a few runs, you have a good seal around the hatch.

Please make sure to shoot some video for us, would like to see it run.

microflitedude Fri Sep 07, 2012 12:23 pm

Not at all, very grateful for your postings.

It does twitch, more than I would like it to. The RX has had a rough life. So you would put the connector inside the hatch, or have it loose on top?

I've got socket heads on there now. I need to find a nice driver that fits them better.

Thanks

PV Pilot Fri Sep 07, 2012 12:41 pm

Personally, I would have that plug down inside the radio compartment,,and still wrap a balloon or some type of waterproofing for that plug end.

Always do a range check on dry land before you launch it. Everything on and walk away as far as you feel comfortable controlling it. Have a buddy standing by to watch the throttle and rudder to see if they go crazy. Run the motor on dry land with everything powered up, and check again. If it is going nuts on those tests, well,, it's your call then. You obviously don't want to toss it in the water if you can't control it sufficiently.

Crystal set radios are a pain sometimes,, they can be very finicky delicate gear.

microflitedude Fri Sep 07, 2012 1:10 pm

Could I use a 2.4ghz JR aircraft receiver?

PV Pilot Fri Sep 07, 2012 1:30 pm

So long as you use the 2.4 transmitter. As you probably know 2.4 transmitters and recievers have to stay paired up. There might be a new system out now that allows both crystal to 2.4 and vice versa,,but unknown to me. Same for crystal radio stuff (paired crystals of the right configuration/ architecture)

SuperDave Fri Sep 07, 2012 1:49 pm

My throttled Sure Start/ Lil' Swamp Buggy combo lauches best at WOT with a gentle "toss" to get it on plane right away. I have an assistant hold the Tx while I do this. Once the boat scoots away I immediately take back the Tx and the fun begins.

The boat is far more responsive to rudder input when on plane rather than when plowing water off plane.

microflitedude Fri Sep 07, 2012 3:18 pm

Yeah, I would use it with my Dx6i.

I have been out running it, and am going to tell in detail how it went.

The good news is, the radio set worked great and didn't skip a beat. Now the bad news.

I fueled it up and tried to start it. First flip it started right up, but died back down. I thought it may be the spring, which was rubbing. I took all that off, and tried again - same thing. Put on a different glow head, same thing. I noticed it was vibrating considerably, so I switched it out with a rubber ducky 5x3. Started it, and the prop flew off. "Okay" I thought, "I'll just tighten it more this time and it should be good to go. It decides to start backwards, four more times.

Finally it starts, peaked it out, back a few clicks, and set it in the water. It wouldn't get up on plane. It got very close though. Throttle response was great, the engine was running like a top, then SHREEEEEEEEEEEK.

The prop flew off. I now have my only rubber ducky prop, an aluminum spinner, and a custom made socket head bolt at the bottom of the pond. The engine is probably screwed up too. It's covered in black/grey sludge, which is mainly oozing out from the drive plate. Probably grinding away at the crankcase; a thrust washer is needed.

Can't decide if I'm going to take all of it off and go electric. The idea seems so nice now.

Sorry I didn't get any video. I was trying to get it running for an hour and a half, and nobody else was around.

PV Pilot Fri Sep 07, 2012 5:19 pm

Dang,,so close. Dont give up on it yet Matt. Pull the motor apart and see if you dimpled the piston with the free rpm's then report back.

Working now but i will check it later tonight/early morning

lousyflyer Fri Sep 07, 2012 5:31 pm

Welcome to the world of boating. You have to be dedicated to run boats. I am not that dedicated.

SuperDave Fri Sep 07, 2012 6:09 pm

lousyflyer:

You should check out my EP Dumas Chris-Craft 28" mahogany speedboat. It's not quite ready to run because I need to do some soldering. It's been over two years in construction.

It's been my most difficult modeling endeavor ever by far.

microflitedude Fri Sep 07, 2012 9:50 pm

I guess I should remove the throttle servo and box now? The throttle sure was nice. Maybe I can rig up one of Bernie's 6 gram servos to control it. How are you supposed to keep the prop screw in? Thread locker?

I'll try to stick with it and work out all the "bugs".

Thanks for putting up with all my questions. I have never owned a serious RC boat before.

microflitedude Fri Sep 07, 2012 10:00 pm

This is a "Rubber Ducky" right?

http://coxengines.ca/cox-.049-propeller-5-x-3-safety-tip.html

Now to find a way to justify buying a $2 prop with $4 shipping...

PV Pilot Sat Sep 08, 2012 3:46 am

Just grab one or two of the LH/Pusher props Matt. A more suitable design for a airboat.
http://coxengines.ca/cox-.049-propeller-left-hand-pusher-5-x-3.5.html

Tower has a rip snorting MA 6x4 that I use on my brushless swamp buggy. really light weight prop,,it litterally screams on a 30C 2 cell lipo brushless setup,,it hard powers the boat across wet or dry grass,,kinda scared to stick it in the water, it's just to much,,lol.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNGV1&P=7

There used to be stiff grey 3 bladed Cox pusher props that worked great,, long gone now I think, wish they were still around.

It can only help things if you remove that throttle servo., just my thoughts and what i would do,,but that's me. I will leave that up to you to decide.

SuperDave Sat Sep 08, 2012 11:07 am

Matt:

I'm running an APC three-blade "pusher" prop and have never had a problem with loosening even when my Sure-Start starts backward.

I'm running Bernie's throttle conversion with "hot" plug to get the best idle speed. I'm using Futaba S3114 micro-servos @ .27 ounces with Sullivan "Golden Cable" control connections. Electrical components are contained within rubber balloons for water protection.

This setup performs great and to my expectations.

microflitedude Sat Sep 08, 2012 8:27 pm

Alrighty. The servo on the transom goes for now. Later on I'll mount a 6g servo somewhere, but not until I get the engine happy.

I've got another problem. The bottom of the rudder is cracked where the pin is that holds it to the boat. Some epoxy should fix it.

You weren't kidding when you said boating required dedication... Smile

lousyflyer Sat Sep 08, 2012 8:50 pm

I have a friend that used to take Ryobi two cycle weed trimmer engines and put them on boats with a direct shaft drive to a prop. The local pond was not very large so he would do all his test runs there. In the middle of this tiny pond was one little clump of grass that was almost invisible.

So he's running his boat back and forth and the throttle linkage falls off, and the little spring on the throttle returns the engine to idle. So he turns the boat toward the shore and "BUMP", the boat runs aground on the clump of grass. But it's sitting there, idling - ding, ding, ding, ding, ding. Just like a regular weed trimmer.

He forgot to bring a fishing rod to retrieve the boat, so there it sits while he hopes it will nudge itself off the clump of grass - ding, ding, ding, ding,ding,ding.
But it doesn't move. He waits, and waits until he realizes that the boat has a quart of gasoline on board and it could probably idle for a couple of hours. Ding, ding, ding, ding, ding with no sign of dying.

Well, there's nobody else there so he decides to leave the boat there and go home and get his fishing rod. 15 minute ride home, 15 minute ride back. Gets out of the truck and walks through the woods back to the pond and there's his trusty Ryobi weed trimmer motor still sitting there after at least 45 minutes Ding, ding, ding, ding, ding, ding just like it was when he left it.

Boats require dedication and patience.

microflitedude Sun Sep 09, 2012 8:42 am

Somebody doesn't like to get wet. Smile

lousyflyer Sun Sep 09, 2012 10:00 am

Rule #1 - Never venture into unknown water to retrieve a toy. Just don't do it. Bring the fishing pole.

SuperDave Sun Sep 09, 2012 10:00 am

When I run my boats, power or sail, I ALWAYS bring my life jacket and fishing float tube. Can you guess why? (In colder weather I also bring my chest-high neoprene waders) Wink

PV Pilot Sun Sep 09, 2012 6:47 pm

microflitedude wrote:Alrighty. The servo on the transom goes for now. Later on I'll mount a 6g servo somewhere, but not until I get the engine happy.

I've got another problem. The bottom of the rudder is cracked where the pin is that holds it to the boat. Some epoxy should fix it.

You weren't kidding when you said boating required dedication...

Sounds good. It should plane for you now Matt, once you get it dialed in. A little shuffeling (weight placement) of the reciever pack might be in order for that, but you are one step closer. If i remember right, that pack should be slightly left to the keel of the boat (looking at it from the back of the boat) and then in the center-ish area of the radio compartment. You might have to play around with that a bit to get the weight distribution correct so the boat floats level for the most part and doesn't turn real tight one way or the other. Basically trimming the boat like a airplane.

When I first built my boat, I didn't get the rudder bearing block mounted straight on the transom, so when I would turn to the left, the prop thrust would blow/wiggle the rudder out of the block. A little dubro collar on the bottom remaining rudder pin material fixed that problem. My rudder cracked out also in the same area as yours I think. Not alot of material to hold that pin in the rudder wood. A little blob of epoxy on BOTH sides so it wouldn't happen again.

Airplane-ing requires dedication also,,just a different, more serious kind.

microflitedude Sun Sep 09, 2012 7:35 pm

Here it is. Sorry for the bad picture, the lighting is really bad in my bedroom - it looks worse than it actually is. I have it smoothed out, all it needs now is some paint.

I opened it up, and it was dry inside. cheers

PV Pilot Mon Sep 10, 2012 6:48 am

Very good, looks lighter already. On a skimp, you cant just coat that Dumas mahogany wood area with epoxy if you like. That stuff is like a sponge and is very brittle. On my boat the Aerogloss paint kept lifting there in that area under the engine stand from fuel. You'll get some fuel soak in that area from the "cast off" of residuals from the motor spinning and such.

SuperDave Mon Sep 10, 2012 9:38 am

For the mahongy finish on my "Lil' SB" I first tried Pacer Z-poxy finishing resin but it never gave me the smooth finish that I was after. I sanded the boat down smooth and tried it again several times.

Finally I sanded it smooth once again and gave the Z-poxy a light coat of Model Master's Clear top-coat spray can varnish. The "Lil SB" Laughing

now looks as I had hoped.

Haven't experienced the "cracking rudder" because I over-lapped the rod/rudder joint with light fiberglass tape. The boat performs to my satisfaction.

PV Pilot Tue Sep 11, 2012 11:53 am

I had the same results and frustrations with the Z-pacer stuff Dave. The stuff would lay heavier in spots than others, creating high spots and it would load the surface with bubbles. Tried everything, a heated mix, thinning, this that and everything else. Frustration got to me,,which is rare. A bit more research and then the wallet creaked open, slowly.

West Systems epoxy to the rescue. Mixed up a slow set batch and laid it on, then carded/scraped off the heavy layer. Let it set for 72 hrs and it sanded baby bottom smooth with no side effects. Filled the mahogany grain just like you would like it to on the first shot. Ready for primer and paint. Been using the West Systems for about 6-7 months now, and so far really good.

SuperDave Tue Sep 11, 2012 12:42 pm

Keith:

Having several coats of "sanded off" (GRRRRRR) Z-poxy my "Lil SB" was plenty smooth before the application of top-coat varnish. The boat looks great now but is probably a little heavy for the multiple coats.

Were I to go for a natural clear mahogany finish again I'd try you suggestion to use West Systems.

Thank you for the tip.

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