MatejO

Interesting reading. My 3,5ccm hydro is allready cutted. But. I will use flat nose on my second build (I was thinking of a 7,5cccm nitro).
Thanks for information. In my country the nitro boaters are building fsr-o mono boats (all from molds) . The design of hydroplanes is a Spanish village for them (like we say
It is nice to hear something about design on base of a real hydros!

Thanks again. I am sure that I will need more of your knowledge in design.

p.s. Do you have some kind of plan for boat that I was looking in the page 7?

Hydro Junkie

If you're refering to the pictured boat you included in your last post, that one is based on the Dumas kit that is being documented in this thread. The cross frames have been changed to include upgrades I've incorporated into the design. The closest design plans I can refer you to for this basic boat would be one of the many boats drawn in set 108 at http://www.nwetonmarine.com
Some of the changes I've made are based on plans I purchased fom Newton Marine as well as from other boaters that have made changes that are known to work, such as changing the bottom profile as I have done. You mentioned the "flat nose", which has me wondering if you're refering to the exposed forward frame or the flat bottom profile. This boat will be getting rounded "bow blocks after the decking and bottom has been installed.

MatejO

Flat nose (for sliding trough the corners-as you said) with the red.
And the nice one.

toyotatruckin

Whiplash from http://blazermarine.com/ one of the top performing hydros on the market (he seems to be having some issues with his website right now)

Hydro Junkie

Okay, I think I see where the problem is. Where you drew the red line is actually where the bottom of the boat is going to be as the boat is pictured upside down. Here's two pictures of the same hull built off plans from Newton Marine rather than being based on the Dumas kit. The area that I was referring to about being flat to help the boat slide sideways is the side of the boat behind the sponsons. The sponson is the the part of the boat that points forward of the center's flat front and is where the boat is the widest. If you follow the boat from right to left, the boat gets narrower. The sides in the narrower area are referred to as "nontrips", which help the boat to slide due to the angle in which they are installed. In the older round nosed boats that raced starting in the 50's, the sides of the boat were vertical with a small area being bevelled. The side of the baot would "catch" the top of the water as it got rougher due to racing and would actually alter the boat's turn, forcing the driver to have to compensate and hope he was able to stay in the boat as the boat was bounced around

advanced builder

I'm smelling nitro. Looks like a K&B red carb. looking-good Buddy That pipe look like a winner. I get excited when I first put that engine inside the hull. Now your cooking Do you have a turn-fin? other than the Dumas one. Joe at Zippkits has a few that may work. I seen his NIB mini Rigger. He released it today. $20.00 off your subscribe to his news letter. I was at Joe's yesterday. He had my trailer and I had his. he blew a bearing last season picking up a snowblower. My son's moving to a new house,soon I have my cellar full. I'm off to Ottawa to race ,I met a few guy's last week from OVR -Ottawa Vally Racers. they came to Elmira. Bunch of good guys. I know no French and I can't hear too good ,should be fun. will that qualify me as a world racer?? or do I need to go the Australia.

Hydro Junkie

Slow Down Dude, that is a sport 40 boat made from Roger Newton Plans. I pictured it to show MatejO a better picture of how the boat will look and to clear up some confusion. You were dead on with the red carb K&B, but in this case it's a .45 with front exhaust, not a NR .21 and a Macs quiet pipe

MatejO

Confusion indeed
The non vertical side for better cornering is logical.
The straight (red line) nose was in my mind all the time.

That is done.
Let's get back to building some hydros!

Hydro Junkie

Unfortunately, this morning I'm in Ogden Utah headed for southwest Wyoming for the weekend. building will resume most likely on Tuesday so stay tuned

advanced builder

Are you lost in the badlands? They have pointy boots down yonder. Dick Chaney lives around there. dead eye dick DON'T shoot
. I seen your post dropping down so I 'll post some to give it a lift.

Hydro Junkie

Nope, not in the "Badlands". I was in Evanston Wyoming for a dance festival weekend. After 16 or so hours in the car each way and two days in Wyoming, I finally got home at 3:00 this morning. This was a good thing, considering that traffic was backed up for 20+ miles on I-90 over Snoqualmie Pass today. As I said in my last post, construction resumes tomorrow now that I've had the chance to recover from lack of sleep

Hydro Junkie

Spent the day at the minimill working on a skid fin bracket for the race boat as a prototype for the Pak. It still needs some final trimming and polishing but, all in all, it turned out nice

advanced builder

Looking good .I just looked inside my new .12 NR yup the con rod bushing is shot. I have 2 Go.18 sitting right here. but we have a problem the Zippkitt is made for a .12 .the width of the hull is off. Now what. more money that's what. I got 1 run out of that rod. Let me see if I can cut a mount or destroy something.

Hydro Junkie

It's back to building time. Today was mostly working on the modded boat, but I did get some work done on the kit build. Today's work amounted to assembling the sponson frames, adding glue blocks to the outside of the sponson chines and sealing them so I'll be able to install at least one sponson side tomorrow. I didn't take any pictures as it's basically the same as I showed on the modded boat in post 167. If anyone want's to see pictures let me know and I'll take some before I install the skin tomorrow.

advanced builder

Putting down the skin is a real joy. All your work is sealed on the inside. Get the sanding blocks out. on to sealing and painting. And Hardware w/servos

Hydro Junkie

I can't help but agree on all of that, though I did get slowed down somewhat. The frail nature of the mahogany has required me to do a little bit of rethinking on the sponson chines. I've decided that the only way to get them strong enough, in my opinion anyway, is to add glue blocks to the inboard side of the chine rails. This, and trying to determine the best place for the outboard side chine glue blocks has had me rethinking how I want to attach the sponson sides. I should have that figured out by the end of the day and have a picture of my solution. This kit's material is totally agrivating[:@]

advanced builder

Dumas still had some old ways of doing things. Been skimping on the Quality of Material for as long as I can recall. Airplanes they sell the most of. Boat hulls are probably a loss money wise. Same with Octura. If they had a web site ,Who knows how much they would make. money wise. Snail mail business.

Hydro Junkie

I finally decided how to strengthen the sponson chine as well as install the added(and not specified in the instructions) glue blocks. I ran 1/8" square stock along the inside of the chine in the aft three bays. this greatly stiffened the chine. I then ran another solid piece along the outside of the chine, butted up against the bottom of the cross frames where the material was removed by Dumas. the next step will be to sand the glue block to a bevel so there will be more material to epoxy the sponson side to. In the pictures below, you can see the difference in thickness between the right sponson chine and left. The thicker block at the front of the sponson is there to give even more area to epoxy the front of the sponson side to as this is the area that will fail first. The reason it will fail at this point is there isn't much gluing area to hold the front of the sponson side.

Hydro Junkie

I have the outboard glue block sanded and, right after I'm done with this update, I'll be mixing up epoxy to attach the sponson side to the kit build and the sponson bottom on the modded boat. The rest of the night will be spent at the mill making a skid fin bracket for the kit boat so I can install it before putting the sponson bottom and deck on

Hydro Junkie

And with all of that, the sponson side is epoxied in place

Hydro Junkie

I figured it was time to show why this build is taking more time than some think it should. Here is a picture of the kit build next to a highly modified and remanufactured Dumas Pak hull. I'm not going to go into all the changes I've incorporated into the remanufactured hull at this time but, in short, it's a major redesign compared to the kit build. The kit build has the right side sponson side installed, only requiring some trimming before the bottom goes on while the remanufactured kit will have the right deck installed in the morning after a little more lightening done to the cross frames between the right sponson inside and right nontrip

advanced builder

I like to use Electrical tape you can stretch the tape some. It does leave a black mark on the ply. but it sands right off. LOOKINGOOD

Hydro Junkie

Glad you approve, considering I've got two weeks to have the redesigned boat done. As they're pictured, the redesigned boat, less deck is about 23.6 ounces while the kit build is 13.75 prior to trimming off the excess sponson side material. It's going to be interesting to see how they compare when the hulls are finished. One thing I'm still debating on is whether I go old school on the drive shaft in the kit and install a hard shaft instead of a flex. The redesigned boat is getting a 3/16" flex drive so again, comparing might be fun

advanced builder

New school all the way. I never ran a hard-drive. Why maintenance. Them needle bearings on each end make for oiling on each end-dirty Dirty inside.
I have a extra one from a Miller America. still setting here someplace. Will never use it. I did goof up my brass bend on the cat. snapped a shaft. I see why my old bend had a ding in the brass at where the flex shaft broke. Ive messed up before.not on a bend in a long time. My new one will work you do enough of em- you get good.

joseywales

You can use clear electrical tape,works great and leave no marks. Most of the time I use the good old 3M masking tape.