Traxxas M41 - Real Speed & Porpoise????

[bonefisher]

Greetings... I acquired an M41 for a great deal to give to my brother who is not a super experienced modeler... but knows enough to make this run ok...

So, I replaced the trim tabs, put in dual cooling, new motor jacket, and a set of nice 60C 5000 3S batteries...

Issue is no matter the battery placement, the boat seems to want to porpoise, but onto to its right side (almost like a torque roll)... I moved the left battery further forward thinking staggered batteries may work, but no joy... I have not tried dropping the left trim tab down yet (both are set in line with hull)...

And I am also topping out at just 38 MPH on the boat... while the porpoising may kill some, I saw on the box it was supposed to be 50MPH?

Would love any thoughts and help... this one has me a bit stumped...

Thanks!!!

[boredom.is.me]

Sounds like you didn't adjust the only thing that needed to be adjusted. It's that thingy that holds the thingy that actually pushes the boat. :)

[Doby]

And I am also topping out at just 38 MPH on the boat... while the porpoising may kill some, I saw on the box it was supposed to be 50MPH?

Would love any thoughts and help... this one has me a bit stumped...

Thanks!!!

Ahh Traxxas and their advertising gets another one!

The 50 Mph claim is probably with the boat properly set up by someone who knows what they are doing (no offense meant) and with an appropriate (non stock) prop in just the right conditions (whatever those may be).

Like boredom said, the height of the prop can also affect the angle of the boat in the water as it runs.

How much adjustment is there for prop height?

What prop do you have on?

[Mxkid261]

The 50 Mph claim is probably with the boat properly set up by someone who knows what they are doing (no offense meant) and with an appropriate (non stock) prop in just the right conditions (whatever those may be).

Yep Doby has a great point. Your probably not going to pull the boat out of the box, toss in some 3s packs and do 50mph Lol. It doesn't matter if Traxxas did 200 runs with the boat and only hit 50mph once, the fact of the matter is they got the boat to do 50mph therefore they can put that on the box

[bonefisher]

Thanks all... def figured there was some overzealous advertising... just seems far off...

Will try to drop the left tab a bit to see if i can get her more in the water...

Would love any other ideas...

Chris

[boredom.is.me]

You completely missed the part where we told you what to do to fix your issue...

[Mxkid261]

A video of it running would help too. Try adjusting the strut, trim tabs and moving your batteries. The manual should have illustrations on adjusting the strut and tabs. Dropping the trim tab is going to put more hull in the water. If you want to go faster, you need to get less hull in the water

[bonefisher]

If I missed it, then my bad... but I did not think "Sounds like you didn't adjust the only thing that needed to be adjusted. It's that thingy that holds the thingy that actually pushes the boat" was clear enough to action upon...

That could be the strut itself, the strut angle, the strut depth, the shaft, the drive dog space, etc... I certainly appreciate the help but did not feel I had enough to work with from that comment...

[Mxkid261]

If I missed it, then my bad... but I did not think "Sounds like you didn't adjust the only thing that needed to be adjusted. It's that thingy that holds the thingy that actually pushes the boat" was clear enough to action upon...

That could be the strut itself, the strut angle, the strut depth, the shaft, the drive dog space, etc... I certainly appreciate the help but did not feel I had enough to work with from that comment...

Like I said, read through the manual and it should have a section on adjusting the trim tabs/strut, and how it affects the ride attitude of the boat

[bonefisher]

Unfortunately manual is VERY light on this... one page... two paragraphs...

No big deal... just seemed odd to be so far off (25%) from speed... will continue to tinker... will try the tabs first...

[fweasel]

angle the strut down, the bow will ride lower, more hull in the water, less speed, potentially more stable. Angle the strut up, the bow will ride higher, less hull in the water, more speed, potentially less stable. I'm not familiar with the M41 strut, so I don't know if its mounting hole is slotted to allow you to maintain a constant trim angle and simply adjust the height of the strut/prop. My 29" Blackjack likes the strut angle level with the bottom of the sponsons and roughly 1/8" higher than even with the sponson bottoms. Raise it too high, speed falls off. Set it too low, speed falls off, electronics get hot too.

[TonyRomano]

Yep Doby has a great point. Your probably not going to pull the boat out of the box, toss in some 3s packs and do 50mph Lol. It doesn't matter if Traxxas did 200 runs with the boat and only hit 50mph once, the fact of the matter is they got the boat to do 50mph therefore they can put that on the box

I just got 52 out of mine!

Stock....

I am having issue with boat bouncing. I swear the overall weight is the reason. So light!

I moved 3s batteries more toward front, not sure if that helped.

New to boats, so any suggestions welcome.

Water is like glass and low wind.

[Jesse J]

If all suggested adjustments still leave the bounce in her step, I’d look at the ride pads and make sure the are flat (no concave spots) - if the are not, then fill with bondo and sand until flat. Also that all the angles are sharp.

If the sponsons are flat and you have pulled all your hair out, you could try a tunnel flap. I have had success with making an adjustable trim tab like flap that works with the air flowing under the tunnel. Possibly an air dam in the tunnel would be something else to try.

[TonyRomano]

The boat is plastic, I do not see any flaws on the bottom. Every “pad” seems perfectly flat. Boat has no wopple on flat surface.

The prop had a slight crack in one blade, if that is the cause then Traxxas makes on hell of a prop. I have a racing prop from “Dasboata” I will try next outing.

Is the goal to have all 3 “pads” on the water? 3 per side that is. Boat should be horizontal to water surface?

[fweasel]

You won't see the imperfections by just looking at the ride pads, unless they're REALLY bad. Take a straight edge and lay it across the width and length of each ride pad to look for low or high spots.

No, you wouldn't want all three ride pads in the water when running. That would be considered running "wet" and with that much hull in the water, will result in slow speeds and potentially higher temps on the electronics. Ideally, a cat will be riding on just the last ride pad as air is packed into the tunnel and pushes the hull up. This can be achieved with a combination of center of gravity adjustments (moving batteries forward or backwards), strut adjustments (angle of prop), height of the strut, and numerous other smaller tweaks.