RE: Rebuilding a 30 year old Dumas DV 40!
Yes that is a standard "Y" cable. The one in the picture was from the plane wing and it was 3 feet. I got a six-inch one to replace it.
Posted on: 6/30/2009 9:55 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8894312

RE: Rebuilding a 30 year old Dumas DV 40!
Performance report: I had the boat out at the lake for a week and got a lot of good runs. I had not commented on engine temp, and the marine conversion because I did not want to give misleading info until I had verified this on the water. Initial temps on land once went as high as 255F with the water bottle about 2 feet above the engine. I was pretty concerned, but in the end all worked out OK as this was a fresh engine (less than 5 aircraft flights in its previous life) and after a few sloppy-rich break-in runs on the water I believe it now runs with reasonable temp. After a run, with a 30 second lag to get to my temp gun I never got a reading over 200F. Mostly 160 to 170F. I ran 15% aircraft fuel and an OS #8 plug after break-in. So I can say that a modern aircraft engine can still be converted to make a good general-purpose non-racing marine engine. I bent the Octura kool-clamp to conform to the square shape of the OS 46 AX cylinder head and also put thermal conducting grease between the kool-clamp and the cylinder head. The flywheel was a Dumas from the original DV-40 kit and the collet was an Octura Flex Coupler for 1/4-28. I kept the original aircraft style muffler (reversed in direction) and used a muffler pressure on the fuel tank. The pressure nipple is on the lower side of the muffler, so I may re-locate the nipple to the top side of the muffler, now that I am pretty sure I'm keeping this engine in the boat. BTW the boat is faster than the old 1975 Fox 45 with tuned pipe that the boat had before. The OS 46 AX has more advanced porting and a much larger carb. So, even with the aircraft muffler, it makes more power than the old engine did with the pipe.
Posted on: 6/29/2009 4:43 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8891683

RE: Dumas Thriftway Too Rebuild
So here is an update on the boat's performance. I had it out on the lake last week and it is great for a 'fun' type boat. I put a turning fin on it and it turns really well. It is a little faster than I expected. Stability was good. It is a pretty heavy package, so its no racer, but certainly more for the pond than the display shelf. There were no driveline or engine problems
Posted on: 6/29/2009 4:17 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8891603

RE: Dumas Thriftway Too Rebuild
The only thing screwed onto the engine shaft is the pilot shaft which holds the flywheel on and provides a shaft on which the clutch bell can spin. There is no collet, The propeller shaft fits into the end of the drive dog and is held in place with a set screw. The propeller shaft is nice in that it has flats for the setscrews at both ends. I got some replacement parts (new pilot shaft, bearing and drive dog) here, and they had the parts in stock. http://www.rchobbyexplosion.com/Megatech_Boat_Parts_s/57.htm
Posted on: 6/14/2009 12:56 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8851023

RE: Dumas Thriftway Too Rebuild
I remember that name from some old Dumas ads. Looks like it is coming along nice. In terms of my hardware, everything is directly out of the Megatech Wicked Angel. It is a .16 engine with a somewhat small flywheel with two RC car type clutch shoes. There is a needle bearing for the clutch bell (the Achilles Heel of the system) and the drive dog is screwed on to the clutch bell in place of the pinion gear that would normally be on a car. The drive dog then goes to a solid shaft that is supported in a stuffing tube. There are bronze bearings on either end to support the shaft.
Posted on: 6/13/2009 5:46 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8849498

RE: Dumas Thriftway Too Rebuild
Some recent pictures showing the completed engine installation and radiobox.
Posted on: 6/11/2009 10:04 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8843708

Dumas Thriftway Too Rebuild
Here are some pictures of a current project. I'm redoing a Dumas Thriftway Too that I built in 1973. At the time it used a huge single channel radio that filled the whole rear of the boat and a control-line aircraft engine. Current engine and running gear come from a .16 Megatech Wicked Angel that crumbled to pieces after a few runs. The little picture is from about 1974, it's maiden voyage. [IMG]http://img.photobucket.com/albums/v670/ic-racer/DSCF4666.jpg[/IMG]
Posted on: 6/11/2009 10:02 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8779257

RE: Flying off water
A lot depends on the plane and how good you are. I also have a cottage in upper MIchigan and only learned how to fly at my local field just so I could get a float plane. I spent one summer learning the basics on land and got a Modelfly Beaver on Floats for the lake. That plane builds and flies very nice. With the Beaver, I had no problem taking off and landing on the water without ever having done it before. That plane is so easy to fly, I would highly, highly recommend it to anyone learning float flying.
Posted on: 6/8/2009 12:59 PM by Author "ic-racer" in the forum "Seaplanes"
http://www.rcuniverse.com/forum/fb.asp?m=8835523

RE: Dumas Thriftway Too Rebuild
Here is the Wicked Angel's stuffing tube.
Posted on: 6/6/2009 12:22 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8830326

RE: Dumas Thriftway Too Rebuild
Here it is while the glue sets on a little bulkhead I made to separate the engine compartment from the radio box. The drive shaft stuffing tube is right from the Wicked Angel. The muffler looks a little funny but I'm not excited about tearing up my mahogany deck to make room for the muffler pointing the other way. A muffler extension would work, but they don't come in this small of a size.
Posted on: 6/6/2009 12:20 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8830313

RE: Dumas Thriftway Too Rebuild
I converted this portion of the hull into a radio box. This will have a plexiglass cover, held on with radio box tape.
Posted on: 6/6/2009 12:13 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8830308

RE: Dumas Thriftway Too Rebuild
I have the servos mounted and the stuffing tube is glued in. Pics to follow....
Posted on: 6/4/2009 9:31 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8824773

RE: O.S. .21 rebuild
I use this for On-Road .21 engines. Though, heating, as suggested works well also. http://www.amainhobbies.com/product_info.php/products_id/3528
Posted on: 6/4/2009 9:29 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8824763

RE: Help with electric plane that can crash land on tall grass
Can't find trainer software for the Macintosh. Does anyone know of any?
Posted on: 5/19/2009 9:32 AM by Author "ic-racer" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=8781301

RE: Dumas Thriftway Too Rebuild
Here is a picture of that airboat design from the original construction article. I don't have a date on the article, but they speak of two channels each for steering and throttle, so I am thinking probably 60s with escapement servos. [IMG]http://img.photobucket.com/albums/v670/ic-racer/MissTake.jpg[/IMG]
Posted on: 5/19/2009 9:21 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8781271

RE: Dumas Thriftway Too Rebuild
://img.photobucket.com/albums/v670/ic-racer/strippingthefront.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v670/ic-racer/sizecomparison.jpg[/IMG]
Posted on: 5/19/2009 9:16 AM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8781263

RE: Dumas Thriftway Too Rebuild
Maybe you can see, I used that trick of heating the fuel tank to melt it a little and re-shape it to clear the flywheel and clutch. It worked out very well.
Posted on: 5/18/2009 3:07 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8779278

RE: Dumas Thriftway Too Rebuild
I'm using these little micro servos because this really is a small boat (24"), and there is not much room. These tiny Hitecs have 33 oz/in of torque, so they will be more than adequate. Interesting that I found the drive-dog adapter to be drilled off-center. I thought the Megatech vibrated a lot, That probably contributed to the early demise of the Wicked Angel :) I found a place that has a new one, lets hope it is straight. Since the Megatech hardware is practically brand-new, I'd like to use it. If I went with another setup, I'd need everything from flywheel to prop and that would be more that I want to spend. I don't expect this to be a super-performer, I'm just re-building it for nostalgia. [IMG]http://img.photobucket.com/albums/v670/ic-racer/DSCF4667.jpg[/IMG]
Posted on: 5/18/2009 3:06 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8779272

RE: Help with electric plane that can crash land on tall grass
Ok, so its belly landing. Am I correct in assuming that this is the standard mode of landing these models? The manufactures pictures etc. show these planes with tiny wheels. I guess that would work if they were "Parking Lot" flier. I 'was' an experienced pilot, but I used the simulator at the hobby shop the other day and boy am I rusty. I also have a nitro Beaver float plane, so this electric Beaver looks about my level. I just need to come to grips that that thing will belly land OK without destroying itself. http://www.rchobbies.org/gws_beaver.htm#
Posted on: 5/12/2009 1:35 PM by Author "ic-racer" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=8762762

Help with electric plane that can crash land on tall grass
About 4 years ago my field was closed down, so no more flying. I have been eyeing my local park as a place to start flying again. I was just out there and the grass is about 6 inches high. I don't think any of my 0.40 to 0.60 sized conventional planes will take off or land on that. I was wondering about those electric planes designated "park flyers" I presume they are hand launched and crash landed on the grass. How big a plane can safely do that. I was thinking a 35" to 40" wingspan plane. Maybe something like the Mini Super Sportster as I used to fly a conventional 0.40 Super Sportster. So, any recommendations of 35" to 40" easy-to-fly planes in the ARF category that are designed to crash land on tall grass?
Posted on: 5/12/2009 10:48 AM by Author "ic-racer" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=8762363

RE: Sig Kadet Mark II Build
I just saw this thread. Good work on your plane. I have a Sig Kadet Mark II also.
Posted on: 5/8/2009 12:21 AM by Author "ic-racer" in the forum "Kit Building"
http://www.rcuniverse.com/forum/fb.asp?m=8750385

RE: Rebuilding a 30 year old Dumas DV 40!
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.
Posted on: 5/6/2009 1:26 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8745671

RE: Rebuilding a 30 year old Dumas DV 40!
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.
Posted on: 5/4/2009 6:19 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8740529

RE: Rebuilding a 30 year old Dumas DV 40!
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.
Posted on: 5/4/2009 6:16 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8740508

RE: Rebuilding a 30 year old Dumas DV 40!
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.
Posted on: 5/4/2009 6:09 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8740497

RE: Rebuilding a 30 year old Dumas DV 40!
Masking and ready for engine compartment re-painting.
Posted on: 5/4/2009 6:08 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8740492

RE: Rebuilding a 30 year old Dumas DV 40!
I filled all the holes in the bulkhead with epoxy. Getting ready to repaint the engine compartment.
Posted on: 5/4/2009 6:06 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8740482

RE: Right Thrust on Strut...
Just so there is no confusion, here is a graphic representation of how I have just set up my strut angle. [IMG]http://img.photobucket.com/albums/v670/ic-racer/Newstrutangle.jpg[/IMG]
Posted on: 5/4/2009 2:46 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8739936

RE: Right Thrust on Strut...
I think there is just a question of nomenclature here. I am referring to the thrust vector that is in the same direction as the direction of travel. That would be the thrust of the water on the boat. This thrust vector is from the transom to the bow; it points toward the front. So, in my case, I am angling that thrust vector slightly to the right. Of course there is also an equal and opposite thrust vector from the boat to the water, and if that is your reference point then, in my vector would point more toward the left. Both ways of describing it are correct but using the angle reference with respect to the direction of travel is the way it is usually described on a plane. When I think of an outboard "pointing" to the left, I was referring to the handle (same as a tiller). But, yes, the prop would "point" in the opposite direction if you use that frame of reference.
Posted on: 5/4/2009 2:45 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8739917

RE: Right Thrust on Strut...
[quote]ORIGINAL: Sean Bowf Wouldnt the thrust be pointing to the left a little?? Or am I misunderstanding?? Propwalk would drag the rear of the boat to the left, making the boat turn to the right. So would you want the offset to try to stear the boat to the left, to counteract the propwalk?? Sean [/quote] Pointing the strut to the RIGHT makes the boat go LEFT. Thats how an outboard or stern drive 1:1 boat steers. I found a little plastic applicator from a BONDO kit that is about 2 inches square that is molded as a perfect wedge. It is 1 millimeter thick at one end and 2 millimeters at the other end. This will make a perfect wedge to offset my strut. I think it will mount more securely than with just two one-millimeter washers under one side of the strut.
Posted on: 5/3/2009 6:20 PM by Author "ic-racer" in the forum "Speed - RC Nitro Boats"
http://www.rcuniverse.com/forum/fb.asp?m=8737357