grant118

My Feedback: (26)

I'm considering building a 1/6 scale hydro (based on unlimited hydroplae of about 30' long x 15' wide). So it would be about 60" long x 30" wide. questions:

1. Is it best to take Roger Newton plans and blow them up to 1/5 or 1/6 scale?
2. What power plant to use to get about 50-60 mph? Singel zenoah, inline twin?
3. Servo size for rudder?
4. Anyone out there done this?

Would like to build a turbine version of a late 80's early 90's hydro

thanks

martno1fan

Best bet is stick to 1/8th scale at arround 46-50" and use a single zenoah,rcmk or similar in my opinion especially if you want to see anywhere near 60 mph which isnt an easy speed to reach.
Mart

grant118

My Feedback: (26)

Thanks for the post Mart. Watching F1 right now. How about that Red Bull team?

I was looking at RCMK inline twin motors. They have one for under $600, 10 hp... thought this would be good for a bigger hydro. I don't plan on racing, I just like scale hydros. Also like the Thunder boats like your zipkits boat... really nice job on that one.
chris

martno1fan

The only problem i see with the rcmk inline is its untested ive not seen many running them as yet so id be wary of buying one untill theyre proven.As for any other inlines like zenoahs i wouldnt even bother they allways seem to fail,far better in my opinion to go with a good single motor.I too am interested in the rcmk inlines but im waiting till im sure what im getting is going to do the job .
Mart

grant118

My Feedback: (26)

Thanks Mart. I want something with more cc's so I can turn a bigger prop. I see people talk about "Blata" engines but i don't know where you can get these or their clones???

Chris

Dreamin Hemi

www.viperhulls.com/

FlogginHarvey

You can get the "real" Blatas from MHZ Germany. I have one in the Apache and it has nice power...they also make a set of mounts and exhaust kit for them...the "real" ones are rated at almost double the HP of the clones.

Not sure if it is appropriate here but I have been thinking about playing with some new power in the Apache and might consider selling the motor, mounts, pipe, etc?

If you are curious shoot me a line at tprice AT villagemarina.com

martno1fan

One thing to consider is the weight of them,will it really be as good as a modded zenoah in something like a hydro,weight is crtitical in hydros as is the cog which might be a big issue with these engines.
Mart

Hydro Junkie

If you want to build a gas powered hydro, take a set of Newton plans and blow them up to 120%. That will minimize the effect of the engine weight some and also make the hull better able to handle the torque of the gas engine. We have a club in Washington State that is racing hulls of this configuration that are stable and fairly fast so I'm using proven info in this post and not conjecture

dicko

Mart,

Lots of people have been running the RCMK inline twins for a while now. Danny at Sonic has been running one for several months & I know he runs every weekend. There are write ups on them on several sites & they are looking the goods. I know Danny said he won't be making any more of his twins any more, not because they failed but because of the time he had to put into them compared to picking up an RCMK off the shelf. I've not heard of anyone having one of Danny's Zen inlines fail either.

Jason.

martno1fan

I think signs are looking good but then again so did the orriginal rcmk then the problems started so im still not confident enough to go ahaead and buy one just yet .
Mart

grant118

My Feedback: (26)

HJ,

Thanks for the reply. If I increase the size to 120%, would it be a 'dog' with a stock zenoah? Or better to go larger? I know this is a open question but I would like to set a goal to go at least 50 mph... What do you think?

Thanks for the other replys as well.
chris

chief3452

Check out Mr. Benoit's boats.

http://www.vintagehydroplanes.com/mo...it_robert.html


I am sure he could provide you with some helpful info on large scale gas hydros. If you click on his name at the bottom of the page it will link you to his email. Hope this helps.

Scott

Hydro Junkie

My preference is to go larger for more stability. What you have to remember is that speed is a balance of boat weight, balance and engine torque.
Since a boat 20% larger doesn't weigh 20% more if properly built, the larger size isn't the problem. Where many have problems is they overbuild or gob on extra epoxy for a perceived added strength. Adding fiberglass or major amounts of extra blocking can quickly add weight to a boat that does nothing for you. Keep your build as lite as possible
A boat that is poorly balanced won't run well either. If it's too tail heavy, at best the prop can't free up and performance will suffer while at worst it will want to blow over. Conversely, too nose heavy will make the boat plow and hard to get on plane.
This brings us to engine torque. You will notice I didn't say HP as HP isn't what spins the prop. You want as much torque as you can get with as much RPM as possible. A low RPM engine won't give enough push to really get a boat running. A low torque engine won't let you spin a prop big enough to push the boat either.

Bhelm

are you looking for somthing like thisto model off of or something smaller? this is 9ft long and has a 300cc single or a 550cc twin that bolts in

tennessee_

I have read about joined crankshaft failures with the inline twin RCMK's but have also read recently of a single piece crankshaft asa fix.

f4joe

Chris,

Call me my name is Joe Steimann and I have a 1/5 scale miss budweiser that I run and I have it running in the low 60's with a quickdraw 35cc. I have the molds for the cowlings for the bud or winston/smoking joes. the boat is 66" long and weighs around 25lbs. it is a very stable boat and runs fantastic. My number is 314 757-6547 I can help you out with almost any questions you might have.

f4joe

[youtube][/youtube]http://www.youtube.com/user/gasprops#p/u/3/RN1H0Ml9C8Q

roostRtale

My Feedback: (1)

I would like to build a hydro close to what you have here. I have an unlimited supply of carbon fiber & resins. With proper planning I believe I can keep the boat ultra lite & not lose structural integerity. From some of my calculations. I should be able to exceed 90mph. I have never built a boat before... But I always say Go BIG or Go HOME. any constructive advise and/or help would be welcome. I plan to begin building mid April Is there anyway I could look at your boat or if you know of one around the Saint Louis area. Just simply enlarging the 1/8 scale plan sounds like the right approach but I believe just increasing the size proportion is a huge mistake. Some custom hull adjustments are going to be calulated from scratch to obtain the proper lift. The degree angles will be off if I use a proportional sliding scale. BUT I could be wrong. as I said I have never built a boat.....YET

Hydro Junkie

Just enlarge a set of Newton plans to 120% and you will be fine. Newton took the time to optimize his plans for R/C, meaning the boat's aren't a true scaled down replica per se'. Something else you can do is contact the guys at http://www.pnwta.org and ask them questions. While you're there, be sure to click on the picture link and check out the fantastic job done on the Elam, a boat that's sporting an RCMK 26

For someone that has never built a boat, that's some serious talk. To claim you can build a boat that will do 90 when guys that have been building and racing for decades, with the exception of a select few, haven't been able to hit that kind of speed has me concerned. That's like saying you can fly a jet fighter before you've learned to fly a Cessna 150. Unless you have a master or doctorate degree in engineering with heavy research on hydrodynamics and aerodynamics, I honestly don't see that happening. Could you give us a few examples of your "calculations" that will let you do what few have been able to do with years of experience?

advanced builder

Now that's some building. HJ that's a nice site. They didn't let me browse much. chief3452 Very nice Keep up the good work all of you. The pleasure was mine. Best post I seen all winter!! of course the Universe.

magnum500

wow this thread needs to wake up

Podagee

Build it big. I'm building the 1994 miss bud 72 inches long and 36" wide but I'm running it electric. 

magnum500

how about some pics podagee

Podagee

It's not my boat and that's not me but it's the one that i'm trying to copy. i'm going to try a 5035-760 motor on 10S. this guy races in new zealand.