ic-racer

I made this fiberglass Dumas DV 40 back when I was a teenager. I re-discovered it about 10 years ago and got it running again with its original engine and its old Futaba first-generation steering-wheel controller.

Now I'm stripping the whole boat and planning on a fresh engine, and new radio. I'll also replace any worn hardware. Lots of pictures to follow.

ic-racer

Here is the To-do list:

1) Radio box (it never had one! I wrapped the radio in a plastic bag!)
2) New engine. (The existing engine was a Fox 45 non-BB. The front bushing is worn out as expected. But this was the only engine I could afford at the time)
3) New strut bearings (see related thread on conversion from needle bearings to lead-teflon bearings)
4) New radio. Nothing fancy, just a Futaba FM reciever.
5) New servos. Again nothing fancy. I have about 15 of the S3004 servos lying around. I'll use two together for the rudder and one for the steering.
6) New flex shaft and new teflon tube.
7) Flex shaft collet. I always wanted one of these. The hardware it had used two grub screws to hold the flex shaft to the engine shaft.
8) New exhaust routing. Now it has a big expansion chamber. This is way too loud for the place I now run. I'm going to use a standard aircraft muffler and route the exhaust out the side, rather than out the back. The outdated Fox 45 made about 1.0 HP with the tuned pipe. The new OS 46AX makes about 1.6 HP with a standard aircraft muffler. So the boat will be both quieter and faster.
9) The flywheel from the Fox fits right on the OS 46AX. The Octura Kool Klamp also fits the new engine.
10) Re-drill the Octura engine mount for the new engine.
11) Shift the engine mount slightly and re-mount it to the hardwood in the hull using fresh holes and fresh stainless steel sheet-metal screws.
12) New silicone fuel and water tubing.
13) New rubber stopper for the Du-Bro tank.

Dreamin Hemi

Pictures? My imagination is down right now.

ic-racer

Here is the old Fox 45 after many years of good service. The replacement is an OS 46AX. This was flown less than five times, and is like new. The main reason I'm using his engine is that our flying field was closed down about 3 years ago and at this point there is no hope of it ever flying there again. So, this will be putting a good engine to good use.

I'm re-using the old Octura engine mount. I have shifted the engine so that the boat mounting holes line up with fresh wood.

RaceCraftRC

Boat pics please!! I am always interasted in the classics!! I thought useing a aircraft engine was a big no no! Don't they get real hot?

ic-racer

Here is the old radio. I'm saving this with the intention on building a 70's vintage 1/8 RC car. I saw an old unbuilt Associated kit a while back but they wanted too much for it.

Dreamin Hemi

Oh wow, I used to have one of those radios LONG time ago, definitely remember those servos. Matter of fact I know where it is! I'll try to retrieve it and post a few pics.

ic-racer

Here is the hull. Its still in very good shape after all these years. The boat did not get a lot of hard use. Mostly because it was precarious to drive, so I was always careful driving it.

ic-racer

Here is the radio box from Aquamarine Laminates. I didn't realize the flange width is not included in the dimensions, so it just barely fits.

ic-racer

Exhaust systems: New and Old.

Nothing wrong with that old pipe, I'll save that for a future project. Back in the day, I wanted to squeeze all the power I could out of that old Fox engine. Now the engines are so powerful that is not a concern.

In fact I specifically avoided that new OS Turbo plug 0.21 Marine engine for this project. My son will be driving this (he is six) and I did not what a powerful high revving engine in this boat. There really is nothing out there in a low-revving recreational marine engine in the 0.40 size, thus the desire to use a converted aircraft engine again.

RaceCraftRC

LOL thats great I love the metal flake !! That is a super old radio, My dad still has one that he had to put together has a kit!!

ic-racer

Here is my rebuilt drive system. I was able to re-use the strut blade by removing the old rusted needle bearings and inserting 3/11" adapter bushings which take the new lead-silicone bearings.

Also, a new flex drive shaft and prop shaft. The prop is one of those "test it and see if its right" plastic props. I was never sure if it was right because it seemed to cavitate in slow corners. Thus, I never got the matching bronze prop. With the new engine, I'll have to experiment again.

ic-racer

A few notes on this hull. It is very heavy! I don't think they make them this thick these days. Also, I got the kit for 1/2 price from the hobby shop in 1977 because the front of the hull was cracked in shipping. My repair added even more weight to the hull.

What this means is that those little Pull-start 0.18 Marine engines are just not going to cut it with this boat. The cool thing is that because the weight of the hull the boat has a very realistic manner in crashing through the waves at full speed. It does not look like those little light-weight boats that just bounce around on the waves. Also, from what I can tell the contemporary 0.40 deep V racing hulls have less of a V and are presumably light weight to aid performance.

As a comparison, my son got a Magnatech .18 as a gift. Even though the hull was almost as long as the old DV 40, the Magnatech just bounced around like a toy. (The worst of it was the Magnatech hull fell apart before the engine was broken in, but thats another story that I am sure has been told here before).

ic-racer

I sanded the engine mount wood blocks to get the engine to tip down about 2 millimeters. Now the coupler lines right up with the hole in the hull.

ic-racer

I found these nice plugs at the hardware store. This one plugs up the old hole where the tuned pipe came through the transom.

ic-racer

I needed to come up with some way to mount the radio box. This plywood plate has stainless steel blind nuts in it. I will fiberglass this to the hull and mount the radio box to this, though it's bottom.

ic-racer

I filled all the holes in the bulkhead with epoxy. Getting ready to repaint the engine compartment.

ic-racer

Masking and ready for engine compartment re-painting.

ic-racer

Here is the new engine. I re-used the existing engine mount. I still need to hook up all the silicone lines and gas tank.

ic-racer

Here is the radio box. It looks like a lot of wire because I am re-using a very, very long "Y" cable from a plane. When I get a shorter one, it will clean things up a lot.

As you can see I had a lot of those 'standard' servos to use up, so I linked two of them together for steering.

I'm still deciding on a good way to mount the switch. The 'access plug' for the finger hole in the radio box cover sticks down about one inch, so I can't mount the switch too high, otherwise the plug will hit it.

The steering control rod is at an angle because it needed to avoid the mounting screws for the strut. The "ideal" route for the control rod would have been right through the mounting hole.

ic-racer

This little plastic applicator from a Bondo kit was perfect in size and taper to make a wedge to offset my strut. You can see it as a flesh-colored plastic piece between the strut mounting and the transom. It had a one millimeter taper from side to side.

advanced builder

Nice rebuild ic-racer,any date to get her wet ?

RaceCraftRC

It looks like its going togther real well.

black talon

My Feedback: (5)

not trying to tell you what to do but i would run a piece of silicone tubing off the muffler and out the back to get rid of the oil coming from the engine. that can make a nasty mess.

ic-racer

Here is a shot from its first 'start-up.' The engine had about less than 5 plane flights on it, and as I recall I had not fully leaned it out yet. Exhaust is carried to the left of the boat via one of those popular grey silicone exhaust extenders. I had been apprehensive about a hole in the side of the boat, but I had to just 'man up' and do it. It turned out great. The rubber extender squeezes into the hole, so no sealant is needed around the hole.

Since the muffler opening points upward, I need to remember to drain the muffler after running.