Fuel

[duc]

Ok here the topic about oil content in our fuel:

You guy's say use no less then 5% castor. I will change the 3% (which I did use until now for the reasons you mentioned) to 5%. Don't want to ruin my engine especially with no parst from K&B left in Europe)

Is 12% synthetic a good average for using on a 3,5 K&B with the 25% nitro?

And when I deside to use 40% nitro does this affect the amount of oil or not?

Last question: Does this all work on the bigger engines like the 7,5 (.45) and 11 (.67) engines to?

Lots of question, hope you guys can help me out.

Later

Oscar

 

[ggillman]

Oscar check this site, It has more info on fuel than any I have seen. "Red Max Fuels" Try the FAQ's and Racing Oil and Fuels links.

http://members.aol.com/FHSoil

Gene ;D

 

[TimD]

Oscar,

I use the following ratio's in all my engines from 21 to 67;

50% Nitromethane

15% Klotz Techniplate (Synthetic oil)

5% 1st pressing castor oil

30% methanol.

Another thing worth mentioning is that after a day's racing I run some 4:1 fuel (20% castor, 80% methanol) through it on the bench then apply the after run oil. The 4:1 fuel get's rid of any nitro still in the motor.

 

[duc]

handling

Thanks!!

By the way my old 3,5 K&B with the car muffler and the OS 2D carb on the abs Dumas Hot shot did do 73,3 km/hr (45,8 mls/hr) last weekend. Stil hope to go a bit faster tomorrow!!

After that I'll try to improve the handling. Even with the cg on 33% the hull flipped with the engine on 0 degrees......

Any tips on this ?

 

[GRand]

let off the throttle a little!!! ;D

 

[duc]

Not until I reach 50 mph

I'm quicker now as Paul from Xtremepowerboats with his 3,5 K&B leecraft but he's planning of buying a cmb greenhead so I'have to set the record as High as possible!!! ;D

(in Holland we don't do races because there are not enough compatitors in each class but we do saw just for fun)

 

[ggillman]

Oscar, very good!!!!

You and Paul keep up the good work, If you can find the stick on lead weights, you might start out by adding 2 ounces to each sponson tip, that should help to hold it down as the speed climbs.

Always nice to hear how my Dutch friends are doing,

Gene ;D

 

[duc]

Gene thanks for the tip!

I already have about 100 gr. of led and a extra battery pack (4 penlites) in front of the radio room, which is in front of the tunnel.

The hull doesn't really flip anymore. After it is in the air and the prop is out of the water the front comes back and mostly it lands head up.

Disadvantage of this setup is when you get of the throttle for a turn the front digs in and the hull hooks......

So I'm thinking of adding weight at the cg......

Not that I like to do that but I don't know any other way.....

Oscar

ps I did try a x440 today but that was really bad. It was hopping al over the water and no speed at all.....

ps2 You guys should try a car muffler to! My old engine with allmost no compression left is really screaming. I can hold full throttle for only a few seconds......and it is quite to

 

[Propjockey]

Hey Oscar...what car muffler are you using?

 

[duc]

I guess you don't recognise this type because I've already posted this one time earlyer and nobody did but here it is:

Mega 21 turbo.

It is a pro pipe for buggy's. But you can use all the serious .21 car mufflers I guess......

 

[TomMoorehouse]

posting for oscar

 

[Jerry Dunlap]

Inquiring minds want to know, "Did the boat blow off, or recover?"

Jerry Dunlap

 

[ggillman]

Oscar, The Sprints seem to turn better if you leave a little hull still in the water, Ha,Ha,

Excellent shot!!!!!!!

Gene ;D

 

[duc]

Tom thanks for posting. (is there a way to do it myself by the way?)

Jerry

Our boating club counts many gas deep vee's, crackerboxes and even some twin (gas) powered hulls. When they are not on the water making big waves it is possible to do this for about ten meters and stil recover

Gene the problem is steering indeed!! But that is because the cg is on 33% and it hooks when you throttle back.

But remember: 25% nitro, old motor with hardly any compression and stil this happens after three or so seconds at full throttle!! I only say this once more: try using a car muffler........

 

[Jerry Dunlap]

Oscar,

There's a reason the guy who designed the 24" Hotshot Sprint 3.5 doesn't run the design anymore - IT'S TOO SMALL FOR THE POWER OF TODAY'S MOTORS!! However, it sure looks awesome blowing off the water.

Jerry Dunlap

 

[duc]

My motor is not really from 'today' but you're still right.

It is nice to drive when you're just having fun though. Would like to get it over 50 some day!

How long is a morden .21 hull? 28" ?

 

[ggillman]

Oscar,

Usually from 27 to 29 inches here in the US,

The Sprints are bigtime fun!!!!!!!

Gene ;D

 

[duc]

hmmmmm well that is a big difference....

anyone ever tried to increase the length of the cavitation plate? Today we had a 7,5 Prather lapcat which had that and the driver was very happy with it. No more blow owers today for him?! ???

 

[ggillman]

I tried adding a plate to extend length on my 3.5, kinda like a Lawless, wound up trying out different mods later to the lower unit.

Gene ;D

 

[Kris Flynn]

hey all

so Oscar you said you use a car pipe on your 3.5? how did you attach it or set it up? just curious thats all

and that is definately a nice pic

Kris