Stock Pursuit with 3660 1620kv 4S = 42.4mph?

[ydesigner]

I have stock TFL Pursuit purchased in October 2016. 3660 2620kv motor and stock 2-blade 42mm prop. I've provided a Seaking 180A ESC and a Turnigy 4S 5000mAh 25-35C battery. I had my old iphone with a Runtastic cycling app on board for a run today. It said I hit 42.4 mph. Not sure I believe that. I didn't think this setup should run that fast. Here's a video:

https://youtu.be/Zg1jN_Tjnwg

Question: is the 42.4mph a believable speed?

I plan on trying x442 and x440/3 props.

[Doby]

yup.

[ydesigner]

Made a run later today. Smoother water and seemed, if anything, faster. App said 26.6mph. I don't believe that either. So much for any confidence in that speed monitoring technique.

[martin]

The first run didn't look like 42mph to me, it also calculates with the stock equipment to around 34-35mph. Which looks more realistic to me.

[Turbo Dan-O]

Yeah, mine went 33 all stock but changing to an M445 picked it up into the low 40s. That stock prop is terrible...

[Newboater]

I have experience with my boat running at 47mph. Not to be rude but your speed looks closer to 32mph

[SD Eracer]

Seems slow for your specs. Did you make sure to do a throttle calibration with your ESC? If you don't, the 180A ESC will only run at about 80% power. I suspect you need to do a calibration, especially how low the rpms sounds on your boat, it definitely isn't running at full power. It takes about 10 seconds to do a calibration, it should be done regularly. Once you do that, your speeds should go up noticeably more than what you are doing now. I like the fact that Aquacraft forces you to do a calibration every time you arm the ESC, wish Seaking would do the same for 180a. I make it a point to sync my throttle every time I put a new battery in.

To do a throttle calibration, plug your battery in (with ESC switch off), turn on the transmitter and hold the throttle at 100%, turn on the ESC. You should hear two beeps, then lease the throttle to neutral, you should hear 1 longer beep. It then should arm normally. Do not adjust the throttle trim on your transmitter after you have done a throttle calibration, if you do, redo the throttle calibration again.

On a side note, a Pursuit with a Leopard 4082 1600kv, 180T, on 6S on a X642 prop will hit 60 mph consistently. This setup is both reliable and cool running. If you want to up your game, get the SSS 4082 2000kv instead, temps will be slightly higher but not by much, speeds will increase to about 67 mph.

However, the stock Pursuit hull needs to be reinforced at the side seams and also the canopy at anything above 50 mph. At least two layers of fiberglass cloth and resin at the seems and at least 1 layer on the canopy. If you know how to lay carbon fiber cloth, even better.

[ydesigner]

Newboater - I completely agree that it did not look like 42mph.

SD Eracer - Thanks for the instructions on calibrating the ESC. I'll get on it. Are you aware of any posts that give good instruction on how to reinforce the seems? What about the bottom, should it reinforced?
-
Thanks for all of the great feedback and suggestions.

[SD Eracer]

Newboater - I completely agree that it did not look like 42mph.

SD Eracer - Thanks for the instructions on calibrating the ESC. I'll get on it. Are you aware of any posts that give good instruction on how to reinforce the seems? What about the bottom, should it reinforced?
-
Thanks for all of the great feedback and suggestions.

Ideally you want to reinforce everything within access. I got most of the seams reinforced on my Pursuit accept for about 5 inches past the beginning of the nose, where I was too lazy to do it. Unfortunately, my Pursuit recently was sucked down underwater at about 60 mph and hit the bottom of the lake, stayed submerged for about 3 minutes before it slowly floated back up to the surface, completely filled with water.
Luckily, no electronics or batteries were damaged since it was freshwater, but the area where I didn't reinforce cracked slightly. Easy fix however.

If you do the seams, nose, and hatch, you should be good. The majority of the hull is thick, but where it connects is the weak points.
Here is a good link that shows you how to do an inlay into a hull. These basic tips, especially on cutting the cloth with tape work just as well when doing isolated reinforcements such as the seams.

http://www.kbbforums.com/carbon-fibe...ial-t1041.html

Just go to Walmart and buy some fiberglass cloth (not the mat), then order some two-part finishing resin, like Z-Poxy PT-40 finishing resin. You will need some throw away mixing cups (use the small medicine sized cups), wooden mixing sticks and some disposable epoxy brushes.

You will then need to cut some fiberglass cloth sheets to reinforce the seams. Using some thin 1/4" masking tape, tape up a 2" x 12" or longer rectangular shape on the fiberglass cloth. Then using scissors, cut right in half of the masking tape until you cut out that long rectangular sheet in the fiberglass. The masking tape prevents fraying of the ends when you cut them for a nice clean install.

I would cut up about 2 sheets for extra strength on each seam down the side of the boat. Make sure to lightly sand the area with some sand paper before you start laying the fiberglass cloth. When you are ready, mix up some resin and apply a thin layer with a brush down the side of the boat. Laying the boat on the side will help here. Then lay down the first sheet of fiberglass cloth, brush some more resin until the cloth is fully saturated. Then lay the 2nd cloth and brush some more resin. Then let it set and cure.

After that, do the other side. I would also do all the edges along the transom as well. For the tip, I would mix a couple of ounces of resin and pour it in so it fills the first couple of inches of the tip of the boat.
This adds a little bit of weight, but really didn’t affect the handling of my boat. In fact, my Pursuit is often complemented for its performance out at the lake.

You could save some weight by using carbon fiber cloth and a roller to soak up the excess resin. But it takes more skill to do it correctly. If you want easy and effective, fiberglass cloth if very effective at adding strength at low cost.

To do the hatch is super simple. Tape up the sides that are painted yellow with masking tape so you don't get any resin on it. Lightly sand the underside of the hatch with some 100 or so grit sand paper. Then cut out a sheet or two of fiberglass cloth about an inch or so wider then the hatch.

Mix up some resin and brush a light coat onto the bottom of the hatch. Lay the cloth on top and brush additional layers of resin until its fully saturated. You will need to sit there while it slowly sets to make sure the cloth doesn't pull away from the more complicated curves of the hatch. Just keep working the brush until it lays flat with no air bubbles.

Once it sets in about 30 minutes, let it cure overnight. Then you can take some scissors and cut the excess cloth around the sides. Then finish up with 100 grit sand paper until all the sides are completely smooth. This should take you about 5 minutes to do, fiberglass sands away cleanly and easily.

Then decide if you need to add another layer, but usually 1 layer is enough for the hatch.

[ydesigner]

SD Eraser,

Thanks very much for taking the time to spell all of that out. Extremely informative! I'm planning on doing some surgery on the boat over the winter and will use these tips.

[SD Eracer]

No worries, I just copied and pasted from my past posts

[ydesigner]

SD Eraser
A couple last thoughts before I get accused of milking the post.

Sorry to hear about your submarine mission, although I'm sure it was earned in an exciting manner. You must be running quite the setup.

Question: what makes working with carbon fiber more difficult than fiberglass cloth?

[SD Eracer]

Carbon fiber doesn't lay down flat, it's woven in a cross cross pattern, you have to work with it constantly until it sets.

It will constantly pull away from the surface until it gets tacky enough to hold.

Fiberglass is about 10 times easier to use, lays down super easy, still very strong especially with 2 or more layers. Though weight is higher.

[ydesigner]

This week I got a X442 prop, detongued, sharpened and balanced it. In hind site, it pretty much matches the prop that came with the boat. No appreciable speed gain. Good experience anyway....
I finally got brave enough to mount my new GoPro on the boat. In addition to the adhesive mount, I added a tether in case the high CG resulted in a bad situation. The water was pretty calm and there were no incidents. You can see the video at the link below. Looks like my starboard side turning fin may be set a little deep.

https://youtu.be/5m-RUPSoUFQ

[fweasel]

runs pretty smooth. Funny, watching the video of the reverse run, it's just like staring out the rear of a real boat, maybe less the turbulence from the turn fins, but realistic just the same.