megamaxx

I am doing my first boat build in over 25 years,i bought a Dumas Miss Unlimited kit. I was hoping one of the enthusiasts here could point me in the direction of a decent marine engine. i am not looking to race, i just want something i can sling out on the water and have a good time with. i have run across the ASP engines at a unbelievable price ,50.00 for a .40( which makes me question it)and then others are upwards of 500.00,then i read researching the forums to beware of plane engines that companies slap a water jacket on and call it a marine engine.........anyway any guidance and info on this will be deeply appreciated

coriolan

If its not for racing, Mecoa has a .46 which is available with or without pull start (kind of a plus for fun running,no starter to drag along!). Would be perfect if your Hydro is one of the 36" unlimited hull. Should be about the same as the K&B .40 used in these in sport-hydro/Div.I in the 80's and not too expensive $99/$139.

Hydro Junkie

Two things on a MECOA engine:
Good luck getting one as I've not been able to get half of what I've wanted from them
That sport engine is a 17K RPM airplane engine with a cooling jacket and flywheel, not a good choise for a boat. You would be money ahead with the OS 18 if you take some time and build lite and liten the hull

Blackout

What length is the hull?

megamaxx

its a 36 inch hull, its becoming quite clear that i have to be extremely careful in my choice,if i under power the boat, wont plane out and be a slug, so me being me thinks that over powering would be better .of course would have to be exercising some throttle control until i get the hull balanced out so i do not launch it..........

megamaxx

http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT





i have found these 2, i like the one with the organ pipes, and i think i can incorporate them neatly into the cowl.

tnltyme

My brother bought one of those motors without the pull start for his 36" Dumas Sport Hydro, Atlas Van Lines, it works great. It's even quicker than the K&B Sport .40............. I wouldn't hesitate to buy one. We're not racers either, but it runs real nice.....

advanced builder

That's a K&B Sport 40 engine. No speed. A putt along engine. `The hot engine is the Nova Rossi at a reasonable price. you can't beat quality http://novarossi.us/
I have a old post on my build of Miss Unlimited. All the tricks are shown. I discarded the sides and went with 1/16 Mahogany and some 1/32 aircraft ply as a backer. I made a sandwich.then epoxied the 2 together. Her are a few tips

advanced builder

one more pic

joseywales

if money is the issue? heres one that would go in your boat. If you run a header and tune pipe on any engine it will perform alot better the those header mufflers. Tune pipes act like a supercharger. Give your engine the extra boost.Like a power band on your dirt trail bike. [link]http://cgi.ebay.com/dynamite-32-nitro-engine-pull-start-/260761608567?pt=Radio_Control_Parts_Accessories&hash=item3cb69a6177[/link]

coriolan

The K&B 40 was indeed just a cross flow scavenged .40 airplane engine with limited rpm hability, but it can swing a bigger prop with more pitch. At a time it was used in NAMBA sport-40/Div-I and you could expect good performances even in those heavy Dumas hydros(most peoples in my club were using the kit's wood only as templates). The Dynamite .32 would be a waste of money at any price and could not move that Dumas hull. In the old days the difference in speed between Division-I Sport-40 (.40/cross flow scav.)and Division-II(.45/Any type+tuned exhaust)was about 20mph which might sound like a lot but each type was exciting to drive and the K&B .40 was a lot easier to deal with than racing type. Have used K&B,Picco and been around all other main brands (OPS,CMB,Rossi) from .21 to .90 for many years and the K&B .40 was the first choice for a relaxed sunday morning at the pond.

megamaxx

thank you all for the great input and info so far,and a special thanks to advanced builder for the great pis( that i will undoubtedly reference through this build)

megamaxx

http://www.rcuniverse.com/market/item.cfm?itemId=733162

http://www.rcuniverse.com/market/item.cfm?itemId=731310


then there are these, the Irvine i have no clue what so ever on,researched it.sounds like a plane engine to me,and the OS .21 should turn the rpm's but will it have the torque to get it moving

joseywales

heres some marine engines..[link]http://cgi.ebay.com/New-Merco-49-Black-Streak-R-C-Model-Marine-Engine-/160565183186?pt=Radio_Control_Parts_Accessories&hash=item25626e42d2[/link][link]http://cgi.ebay.com/Marine-Engine-0-61-ci-9-97-cc-HB-PDP-mount-/110668000392?pt=Radio_Control_Parts_Accessories&hash=item19c453ac88[/link][link]http://cgi.ebay.com/FISHER-REDSHIFT-60-MARINE-GLOW-PLUG-ENGINE-RARE-/170623123744?pt=Radio_Control_Parts_Accessories&hash=item27b9ee4120[/link][link]http://cgi.ebay.com/HB-40-MARINE-ENGINE-WATER-COOLED-HEAD-/230593406793?pt=Radio_Control_Parts_Accessories&hash=item35b0702749[/link][link]http://cgi.ebay.com/K-B-40-ENGINE-WATER-COOLING-HEAD-/230593408124?pt=Radio_Control_Parts_Accessories&hash=item35b0702c7c[/link]

advanced builder

We also forgot the Go Marine. I'm not sure who's selling them now. Good find JW and megamaxx My K&B.67 was my first engine. I'll never sell that engine. The K&B .21 isn't a bad choice. http://www.mecoa.com/index.htm
my mahogany came in the carton I have 1 sheet is left. I used it all on stuff. http://www.midwestproducts.com/

joseywales

nationalbalsa.com 413-277-9500. [link]http://www.nationalbalsa.com/birch_plywood_s/138.htm[/link]There prices are cheap! I'd just got back from toleto hobby show and they was there. Got two sheets of 12x48 of 1/32 and one sheet of 1/16 ply. costed me 25.50! Costed me 8.50 asheet=way cheaper then hobby shops that charges 20.00 asheet! The sheets are birch ply. If that was my boat? I would skin it with 1/32 ply. By doing that will lightern it up. Going to order some more from them.

Airbear

No such thing as to much power, if it will float , if it sinks......... then its to mucmh motor

joseywales

yes there is. Wife has a 1/12 oberto hydro with a CMB.21 RS Redhead that if she goes over 3/4 throtle it will get to squarly and blow over. So to much power can hurt. over kill. You want to have fun running it without worring about blowing over or wrecking it.

megamaxx

joseywales I would skin it with 1/32 ply. By doing that will lightern it up. Going to order some more from them.

good idea, i will keep that in mind

advanced builder

I did happen to notice Midwest changed the site. you can no longer buy bulk. Good site JW Also, Ck your local hobby shop. Happy boating.

joseywales

also you should replace all the mahogany too.. Wife built a dumas sport40 eagle. The mahogany if not carefull it will fray apart. Don't like it. Unless your is in good shape? Think wifes kit was old.

Hydro Junkie

JW, I want to thank you for two posts:
1) Wife has a 1/12 oberto hydro with a CMB.21 RS Redhead that if she goes over 3/4 throtle it will get to squarly and blow over. So to much power can hurt. over kill. You want to have fun running it without worring about blowing over or wrecking it.
2) You should replace all the mahogany too.. Wife built a dumas sport40 eagle. The mahogany if not carefull it will fray apart. Don't like it. Unless your is in good shape? Think wifes kit was old.

These are two thiings I've been trying to get people to understand for years, nice to see you're FINALLY AGREEING WITH ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

1QwkSport2.5r

Thunder Tiger makes a few marine engines.. for a 36" hull, perhaps the TT Pro .46M would be a possibility?
http://www3.towerhobbies.com/cgi-bin...&I=LXAHSX&P=FR ($150)
http://www.canyonhobbies.com/Product...54&click=62061 ($130)

23,000rpm should be enough to move it well, I Think.

joseywales

not really. I have a friend that has on in a V and its a slug.

joseywales

If she had to do another Dumas kit. She would be scrapping all the mahogany. If I remember it was 3/16 frame work. Would've done it 1/8 ply,even light ply would be a better upgrade then that mahogany.