HK/TFL Pursuit Mods

[Hydrocarbon82]

The HK Pursuit was on sale so...I got it in 5 days from AZ to WI, zero damage. Their website doesn't show updated pictures, so I hope this helps somebody.

The first thing I did was order an OSE single-piece driveshaft. This version uses a full 3/16" shaft, 1/4-3/16" teflon stinger bushings, and 7mm stuffing tube with teflon liner. I got it set up with a Flycolor/Raider 150A with the stock motor & M445 and it only did 36mph - really disappointing. I put in a GoolRC 3674 2250kv and that bumped it up to a consistent 43.3mph, but the ESC was thermaling on occasion. Batteries are Gens Ace 5500mAh 45C 4S.

I decided to reconfigure a few things. First was the stinger - I replaced the lead teflon with 1/4" x 0.014" & 7/32" brass tube to replicate a Speedmaster bushing. The bushings came out with a drift & hammer, but the brass needed some mild sanding. While doing that I noticed the stuffing tube was drilled nearly 1/8" off from the stinger centerline! TFL used a nice silicone gromit, but it doesn't let the tube move down low enough. I just hogged out the hole & added some silicone.

After that I put new SS bearings in the motor. I also changed from 4mm to 5.5mm connectors on the motor. The last thing was to shorten that strut turnbuckle on my lathe. It was maxing out while the strut was even & has more adjustment now.

Next test lead to zero esc thermaling, much cooler motor, and an increase to 48.5mph. It was a busy day on the lake with some mild chop. It still seemed to ride perfect in the water, so I decided just to enjoy it rather than try strut adjustments. Keep in mind this motor is nothing like a Leopard. It's a $23 motor and I'm fine with performance since it's a sport boat.

To condense speed info:
36mph - stock 1620kv motor, M445, mis-aligned strut
43mph - 3674 2250kv motor, M445, mis-aligned strut
48mph - 3674 2250kv motor, M445, speedmaster-style bushing
39mph - same as last but with 2x SPC 2S 5000mAh 40C instead of Gens Ace 4S

[runningman]

What runtimes do you have?

[srislash]

Good improvements, nothing wrong with 48mph. Good work

[iop65]

Prop needs some sharpening

[Hydrocarbon82]

I didn't want to go too far since it's just a sport boat prop. I know it's far from a "bad job", as this M445 is on par with my X642. It was a little faster on my Revolt and a little slower on my Shockwave. The guy who sold me the X642 thinned the heck out of it, sharpened it like a steak knife, de-tongued it, and claimed to have checked it one of those expensive prop modding/measuring rigs.

As far as run times, I can't really say since I mix full throttle passes along with holeshots & slow sweepers to entertain the kids & dogs. The first runs before the stinger mod were 5 mins max & runs after felt like 10 mins. I actually pulled it in before LVC because I thought it wasn't working.


The next step is my custom datalogger. I could have bought an Eagletree, but I wanted bluetooth so I don't need to pull the hatch. It's $15 in parts and will use a 200A version of the Allegro amp sensor, a 10hz ublox GPS, and IC-type thermisters. I also want an RPM sensor, either optical or hall.

[runningman]

Interesting. I put 2200kv motor and with m440/3 prop got 72.9km/h. on 2x5000mah batteries. But not sure if my run times more than 5 min. m445 should draw more umps on more kv motor. No?

[MadProps]

The first runs before the stinger mod were 5 mins max & runs after felt like 10 mins.

whats the stinger mod you did?

[runningman]

The first runs before the stinger mod were 5 mins max & runs after felt like 10 mins.

whats the stinger mod you did?

Just O-ring mode. Nothing special.

[MadProps]

Just O-ring mode. Nothing special.

OK....I was trying to account for your increase in run times

edit: possibly you were running a little wet and then you changed the angle a wee bit positive doing the mod?

[boatsrnew2me]

Mine ready for a evening run 20170918_145905.jpg

[runningman]

OK....I was trying to account for your increase in run times

edit: possibly you were running a little wet and then you changed the angle a wee bit positive doing the mod?

I think you need to ask Hydrocarbon82, not me :)

[MadProps]

Mine ready for a evening run 20170918_145905.jpg

what motor are you running?
I just tested mine with a new 4082 1600kv 42mm octura 2 min ago, runs great, started to do a little tuning then it started raining on me ....will also try a 45mm octura when the rain stops

good luck on the run tonite!

[Hydrocarbon82]

Looks like a healthy 6S setup, Boatsrnew.

whats the stinger mod you did?

Straightening the flex cable's transom exit & replacing the teflon bushings with 2pc brass bushings. The cable has 1 bend now instead of 3, so a bit less friction at 30k rpm.

I eyeballed the strut as level as before. I think it's just good a better combination of strut angle, motor connectors, bearings, and flexshaft friction.

But not sure if my run times more than 5 min. m445 should draw more umps on more kv motor. No?

I'm not a prop guy, but what I've seen shows a 445/2's load similar to a 440/3. 73kmh translates to 45mph. Before the mods I considered a 442/2 due to overheating. Most people seem to run ~2000kv in a 4S Pursuit with an M445, so we're probably near the limit.

[MadProps]

I think you need to ask Hydrocarbon82, not me :)

ya I got members crossed

[boatsrnew2me]

what motor are you running?
I just tested mine with a new 4082 1600kv 42mm octura 2 min ago, runs great, started to do a little tuning then it started raining on me ....will also try a 45mm octura when the rain stops

good luck on the run tonite!

leopard 4082 1600kv with a ose b&s x645 . my best run has been 57.4 . todays best 52.1 ,i could use higher c lipos . most are 50c .achieved my best speed on my turnigy heavy duty 3s 5000 60c set .they are some stout lipos for sure .

motor barely gets warm ,highest i have seen is 105 ,most times high 90`s . the flycolor 150 esc gets a bit warmer then that ,i have seen 150 on the caps and 135 on the sink.
after a few hard passes lvc kicks in and i have to slow down or stop for a few until the lipos recover ,then its back to the races .the flycolor esc does a good job of protecting my lipos so that doesnt bother me .

i set my timer for 5 minutes and my lipos come in at about 30%. i have never tried the front lipo tray ,i went this way because i already had a bunch of 3s lipos for my other boats .

[MadProps]

i went this way because i already had a bunch of 3s lipos for my other boats .

me too
my temps were 90-95F
my LVC also kicked in so I lowered that setting because I run with LV alarms and a timer
I now have the hull dialed in will get a speed check tomorrow

what timing are you using I set mine to 11.25

thanks

[boatsrnew2me]

me too

what timing are you using I set mine to 11.25

thanks

same here

[Hydrocarbon82]

Talk about timing got me thinking. I believe I had mine set to 3.75 or even 0 degrees for another [delta wind] motor. I'm going to try 7.5 & 11,25 degrees next time, it should be interesting.

[MadProps]

talking about timing......
without a data logger what should one expect to see when advancing timing to get better running motors...hotter esc, motor, batts?

[Hydrocarbon82]

Yes everything will get hotter, more timing generally creates more load (amps). The "sweet spot" is generally no hotter than what a non He-Man can touch for over 5 seconds. Once you pass the "sweet spot" for a particular motor or setup, it will use a lot more amps for a marginal speed increase. In some cases you'll draw more amps but be slower, particularly true with delta-wind motors.

You can also lower timing below the sweet spot if you need less heat but can't prop-down, or if you need to run the hull wetter due to chop.

[MadProps]

Yes everything will get hotter, more timing generally creates more load (amps). The "sweet spot" is generally no hotter than what a non He-Man can touch for over 5 seconds. Once you pass the "sweet spot" for a particular motor or setup, it will use a lot more amps for a marginal speed increase. In some cases you'll draw more amps but be slower, particularly true with delta-wind motors.

You can also lower timing below the sweet spot if you need less heat but can't prop-down, or if you need to run the hull wetter due to chop.

thanks

[Hydrocarbon82]

I got the gps unit working and tested some old 4s turnigy batteries in parallel. Max was 48.6mph. The gens aces did a little better at 50.5mph.

The great thing about this gps is i don't have to pull the hatch off to check speed. I drive it next to the pier, connect via smartphone, and it spits out the numbers below. When i send a command it resets the max after saving it.

[Hydrocarbon82]

Slow-motion vids of the 48-50mph runs. Only time it chine walks is after a few decent waves at full speed. The turnigy batts put the CG 35-40% from the rear but didn't alter speed much.

[Hydrocarbon82]

It sounds pretty cool at half speed, almost like a full scale boat might from a distance

[Hydrocarbon82]

I set timing to 7.5*, raised the inner trim tabs just above flush, and trimmed the strut down 1/2 turn. Best speed was 51.8mph. It would start skipping on turns so I put the outer tabs down a bit, but it was also fairly rough water. I got some air a few times but this boat just don't want to flip. My last 2 boats would practically flip at random above 35mph, and trimming them down just lost speed.

[T.S.Davis]

Good ole' Pursuit. Great boats.

[runningman]

Cn you show what you changed lead teflon with? And how it looks like now.

[Hydrocarbon82]

Cn you show what you changed lead teflon with? And how it looks like now.

Unfortunately it looks virtually the same. Look at post #1 - picture #4 shows the 7/32" floating bushing already on the flex shaft and #5 shows the stinger with the 1/4" tube installed. First I pressed out the lead bushings by hand with a drift (towards the front), next I cut a 60mm length of 1/4" x 0.014" tube, then chamfered the edges & sanded the OD before pressing it in. I had to put the stinger on a wood block to tap the 1/4" tube in. I tried a drop of loctite but started grabbing before it was in half an inch.

I found a pic with the K&S tube in the stinger for a test fit:

[Insanity Plea]

I like the stinger mod, I was thinking of doing something similar, thanks for sharing. I've already done the 3/16 flex upgrade and installed a Leo 4075 1750kv, running 5s with a X642 from Dasboata. 48mph has been my best of two outings, stinger is strait, temps are around 110. Fun little boat to play with...

[MadProps]

Unfortunately it looks virtually the same. Look at post #1 - picture #4 shows the 7/32" floating bushing already on the flex shaft and #5 shows the stinger with the 1/4" tube installed. First I pressed out the lead bushings by hand with a drift (towards the front), next I cut a 60mm length of 1/4" x 0.014" tube, then chamfered the edges & sanded the OD before pressing it in. I had to put the stinger on a wood block to tap the 1/4" tube in. I tried a drop of loctite but started grabbing before it was in half an inch.

I found a pic with the K&S tube in the stinger for a test fit:

Im a little confused here are have you discarded the bushings completely and running on the 1/4 tube only?