Dumas 7.5 Sprint /wood...setup

[Bobboat]

I was wondering if anyone has any input on set up for the wood 7.5 sprint.I am ready to start painting and would like to know if any weight should be added for proper balance or any other things that may help performance that would take place before blowing alot of time on trick paint.Thanks very much.

 

[Jerry Dunlap]

Bobboat,

I would recommend adding 4 oz. of lead to the front sponson tips - 2 oz. in each sponson tip. With the wood hull, cut an access hole about 2" from the sponson tip. Then mix up 2 oz. of chopped up lead and epoxy and insert this mix into the sponsons. Place the boat on the floor with the sponson tips down. Once the "lead soup" has hardened, cover the access hole with a piece of 1/16" plywood that extends from the sponson tip back about 3". Make the cover strip the same size as the sponson bottom.

Jerry Dunlap

 

[Bobboat]

Thanks alot Jerry,much appreciated...........

 

[Bobboat]

Hey Jerry,what do you like for a prop on this thing.I would guess I will run a pretty much stock 7.5 KB

By the way,my 3.5 W.O.F. is almost done,cant wait to try that,the plans for it were great.

 

[Jerry Dunlap]

Bobboat,

A good prop for general sport running is an Octura X447. Just balance it and it should work fine for you.

Glad to hear the WOF 29 has worked out for you .

Jerry D.

 

[Ron Olson]

Jerry (or anyone else), have you tried the M447 prop? I got one last year but din't get much time to play with it before it got damaged. For those that don't know, it is an Octura X447 with a lot of the leading edge removed built for a 7.5 OB tunnel.

 

[Jerry Dunlap]

Hi Ron,

Jeez, I don't think I've even seen a M447. For 7.5 tunnel heat racing, I usually use a 1450 that's been back cut and had the blades slightly cupped. However, for someone just starting I think using a stock propeller is much easier.

Jerry