Impulse 31 porposing at full throttle.

**magnum500sw** · 09-07-2011, 08:46 PM

i`m just a noob and im sure someone with mono expertise will chime in but i think your bats are far enough ahead , i`d try adjusting the tabs slightly . i think if the bats go too far ahead you will have some turning issues .

**Racer944** · 09-07-2011, 09:50 PM

A combination of things may help... Determine and set your center of gravity on the boat. It should be about 30% of the length of the boat from the transom. Set your batteries in such a way to have your CG as close to that "ideal" as possible as a starting point. Next check your strut and set it level as a good starting point.

Run the boat again and see what happens. If still porposing then try adjusting the trim tabs down and retest and see what changes. You can also try moving the batteries slighly forward to move the CG forward then retest. In the case of tabs down and/or batteries too far forward, worse that will happen is that the boat has trouble getting on plane and rides with too much hull in the water and you loose speed. Be sure to try one thing at a time though so you know what is helping and what is not. Too many changes at once and you won't know whats doing what...

Eric

**svtfrank** · 09-07-2011, 10:19 PM

I had the same problem right out of the box. I put a degree or 2 of trim tab down and all porposing gone. Now i just have to get rid of the chine walk. I've seen Impulses running in the 50's to low 60's perfectly smooth. I'll get her there. You will too! This is a great boat w/TONS of potential!

**Mtwinste** · 09-07-2011, 10:33 PM

Move them all the way forward and test then move them back 1/2 inch at a time until it start bouncing again then move 1/4 inch forward until it stops. This way you have least amount of now in water as possible.

**burgerchow1** · 09-08-2011, 12:29 AM

My first time out of the box, mine opposed as well. Brought it back to the dock and bent the trim tabs down a degree and it was perfect.

**Steve@TheHardRichards** · 09-08-2011, 04:36 PM

Hey, thanks for the fast replies ! I found / set center of gravity at as close to 30% as i could determine(it was pretty much there). Still a slight porpose. Charging again now and im gonna give the tabs a slight 1-2 degree bend down this run. if it chimes,ill reverse the tab change and try a strut adjustment., thanks again..
Oh yeah, this thing is fast as .... allready. I little dialing and it should be that more of a beast.

**Steve@TheHardRichards** · 09-08-2011, 10:26 PM

Ok,got it.I even think im getting the hang of what the changes do to the performance,ride of the boat!(its a little different then the r/c cars ive run for years)

I ran it with the first changes stated in post b4 and it ran bow down and no porposing,but a bit slower then before( due to more hull in the water i presume ).She also chime walked a little.
I moved the battery back to the original settings ( 1/2 inch up from rear of battery box) and left the trim tabs bent down at about 2 degrees down from stock.
She was a tiny bit slower out of the hole but screamed at full throttle ,with very little chime or porposing.
Think i will upgrade to true "adjustable" trim tabs. Any suggestions?
I also took some very fine wet sand paper and lightly (very lightly) sanded the imperfections out of the stock prop.(it had a few little nubs ,and a tiny nick)
Overall i will have to say this boat is impressive,and i look forward to some slight mods in the years to come.

trim tab suggestions?

**Racer944** · 09-09-2011, 09:31 AM

Good news!!

For trim tabs I took Darin Jordan's recomendations; the trim tab mounting holes match exactly the bolt pattern on Speedmaster tabs from OSE (see URL below). They need to be modified slighly though to be able to adjust properly.

See this thread - Post #13 and 15:
http://forums.offshoreelectrics.com/...-quot-Deep-Vee

See my reply in this thread for more pics - Post #2 and #10
http://forums.offshoreelectrics.com/...-31-misfortune

OSE link to SpeedMaster trim tabs: http://www.offshoreelectrics.com/pro...d=ros-spdt-150

Cheers;
Eric

**FE_Chris** · 09-17-2011, 10:55 PM

I went to run mine for the first time today and it was SLOOOOOW. It was porposing at WOT and needed WOT to even get on plane. I estimate she was doing maybe 15-18MPH. Not fast at all. I was running 4s1p Zippy 5000Mah 40c packs.....

I have been reading and it looks like I may need to bend my tabs down a hair, but what about the strut? Any advice on where to place the strut running the stock prop?

I will say, overall the boat is excellent quality....very nice....

**Steve@TheHardRichards** · 09-18-2011, 01:45 PM

well stock form, with (2) 5000 , 30c 2 cell lipos gets me around 34 avg. mph according to my gps on my phone. i run the strut about 2 millimeters lower then stock was on boat(being factory assembled ,not sure if they are all gonna be the same ) but looking at the stuffing tube the shaft is just a hair off center favoring the bottom of the tube. ( i dont know if that made sense,little hungover today)
Im running the batteries to the rear, with the tabs just bent down a hair( lake side trials prove these tabs make a huge impact with little adjustments.
1 adjustment at a time is suggested so that you can come to understand the way your boat and equipment reacts to the changes.
I also took a small xacto knife and made a little line where the stock strut lined up on top of the mount,so i could easily return to the exact same spot if the changes where wrong.
have fun and good luck..

Lol ,i m addicted to fast boats now.... i built a pvc trailer to tow behind my axial scx10 honcho and built a launch ramp/marina on my small lake behind my house. My wife,neighbors and friends all think im nuts...

Impulse 31 porposing at full throttle.

Impulse 31 porposing at full throttle.

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