7.5 Hawk

[gooycheese]

I'm not real sure I mentioned this, but during the last heat of Saturdays race my boat was acting real weird last lap started bogging down. I wasn't really sure what was going on but the boat did finish the race and when I went to bring the boat in it wouldn't shut down with the TX so I was a little confused and why this was happening. Today I have been doing some setup and fixing of the boat since the race and discovered the control arm on the carb had come loose, I got really lucky the boat decide to get stuck on slow it could have been a really bad day.

Paul

 

[gooycheese]

Hi all,

I am hoping someone will have an some direction for me to look for answers. I now am running a Mac .45 in my Hawk. I think I got the ride worked out the boat doesn't hop as bad, today wasn't the best day to check for that because of the 28mph winds but the boat did fine. The problem I am having is the boat wont hit the pipe, I am using an OPS6280 with a rumracing muffler and I am running it at 10 1/8" right now on 50% nitro. Here are somethings I think maybe I should try first reducing the stinger to 3/8 will that help? Second Running the pipe a little shorter? Third maybe 60% nitro? Fourth maybe try and get a AB parabolic? The boat is only hitting 50mph and a 1455 and 1457 prop get the same speeds. Please Help I am looking for advise on things I should try first.

Thank You,

Paul

 

[Tofastformellow]

try a mc 59 plug , sounds like the plugs are to cold to me.

Jason

 

[aaron alberico]

Paul

First shorten your pipe, at least 9-1\2in or even shorter

you will have to reduce the stinger size to about .375 or little bigger for the mac

or parabolic pipe about 9-1\2 or shorter

and go with 1655 prop with about 4.3 to 4.5in cup

you should be running 70mph+

good luck

regards Aaron

 

[gooycheese]

Thanks all,

Ok from what its looking like the 60 size pipe without a stinger reduction could be the problem along with it being longer than whats recommended for a 45 pipe. It has been suggested to me that the volume of the 60 pipe is more and I am running the larger pipe longer that what the 45 pipe should be, does this sound correct? If I shorten the 60 pipe and reduce stinger will this help? I have looked for 45 AB parabolic and have had no success, will the AB 45XT pipe work just as well as the parabolic in this case? Using the 1455 prop I should be able to get the engine to pipe up pretty easy I would guess, am I wrong thinking this? Please Help, I am looking into sleeves & pistons and pipes now ( I am hoping to make this engine preform before the winter season).

Thank You,

Paul

 

[gooycheese]

Hi All,

Did some running today, boat ran better and tried different lengths on the AB XT45 and it did seem to hit the pipe. I do get the hops every now and then and it seams like it only happens when I cross my wakes on an angle or sometime for no reason it just gets the hops? Im running strut at the same angle as the rear sponsons, I have heard it could be my prop does this sound like it could be the problem? I have maybe 3 degree's AOA on the front, sometimes i think the boat looks great and then others its actually jumping out of the water? A little confused?

Thank You,

Paul

 

[Topfuel666]

Paul,

What is the actual negative strut angle set at then? My strut is set at 1* negative, more and you tend to introduce hopping. My angle was more and the hopping was really noticable. If you bring the rpm up, it will become more noticable. My strut bottom is flush with the botton of the rear sponsons on an SGX hull.

Bill

 

[gooycheese]

I am not exactly sure but i think my angle is .5 , I think I will try going with try with a flat and work from there. I hope to run with Tom Moorehouse in the morning and maybe he will be able to suggest some things to try. I will also try and get some video of how the boat is acting. Thank You for all the Help, sorry I ask "dumb" questions but am trying to learn as much as I can.

Thank You,

Paul

 

[Dr Hydro]

Thank You for all the Help, sorry I ask "dumb" questions but am trying to learn as much as I can.

Thank You,

Paul

Asking questions is "smart". Not asking questions is "dumb".