"Q" Outboard tunnel discussion. 6S motors and ESC's?

[HTVboats]

On another tunnel thread the subject of 6S equipment came up and I think it merits a stand alone discussion. I have been testing several combinations with 30-36 inch hulls that were converted from .45 nitro hulls. The information I am posting here is from my on the water experience. I am looking forward to actually racing heats in Charleston in two weeks at the World Tunnel Champs. Should be some good knowledge there and 4 dedicated FE classes.
First point is the lower unit. I like the K&B or Lawless .45 size lowers with Hyperformance adapters. Simple bolt on availiable equipment.
For ESC's I have used T-180, Swordfish 200-220-240-300 amp units and Castle 240 plain and Ice.
For motors I have run everything from 4074-4082 Leapards 1515-1520-1521 Castle and Neu, plus a Scorpion 4020 outrunner. 1250 to 1900 KV's.
If you are converting a .45 size nitro hull I would recommend a Leopard 4074/1400 or 4082/1250kv for economy and a Neu 1515 1.5Y 1500kv or Neu 1521 1Y 1600kv if you want a bit more quality. The higher KV and watt motors can be run on 5S to start with to get proper setup on the boat. A 1520/1600kv with an m445 on a good hull is capable of 55-60mph in heat race trim and mid 60's with an aggressive prop. Bottom line is there is more HP here than these boats can handle. Finding a larger hull and more hp will just create a new set of problems. If an honest 50-65mph isn't enough go for it.
For ESC my favorite is a SF200 for price and it has data logging. You can toast it with a 1520 motor and aggressive props. I like it because it is compact and narrow and fits in radio boxes easily. From there a SF240 or Castle 240 Ice will give you all you need. The SF 240 is larger. Another good choice is a T-180 but I have had difficulty fitting them in boxes with cooling lines.
I am taking a 1250 Leopard / SF200 to run Q class at the worlds and my son's Q tunnel in open class will be a 1520/1600 Castle with a SF240. 2 3s 6000ma in series on the 1250 and 2 6S 4000ma parallel for the 1600. These will cover 6+ laps and come in at 3.7-3.8v per cell.
I you have a Q OB lets hear what you have and if you have questions this thread is open for business and I hope others will share their successful setups.
Mic

[kendt]

Good timing. I am just finishing up a ts3 build for 6s. (even though I was told it couldnt be done he he). I did a fair amount of work to re enforce the transom so I could use a 7.5 lower unit. For now I will go with the bullet drive. Only because I need to do some cutting on my k&b lower to get some weight off. I will start with the bullet dr and see how it goes. For motors I have a scorpion 3226 1600kv. It should be a good match for this size hull. I also have a 3659 edf motor. It is a 1900kv motor though and likely too much for this hull but once I have my hull set up and running well, I will likely try it. as for props i will be keeping it small until i have logged some good data. I couldnt afford a sf 200 for this build so i had to go with a 120. I have a couple of t180.s but there was just no practical way to get it in the bull.Hopefully be testing in another week.

[Grazacind]

I run a QS370 with a 7.5 Hyperferomance lower and 1520/1600kv with sf200. This runs really well. I then change to a 1518 for a bit straight line fun.

Cheers Andrew

[kendt]

For me Its all about the speed in the turns. I dont race, just play for fun. If the boat has blistering speed down the straights thats cool but if you have to come to nearly a full stop before you turn than not so fun.I see that with many cats. they are wicked fast but dont turn worth a dam. If I am unable to maintain decent speed in the turns with my ts3 and the extra weight of a 6s setup, not much point in swapping motors for more speed.It seems like a good design but time will tell. Worst case I will switch to a 3s setup down the road. That way i can still use my 3s packs for my 6s boats.

[properchopper]

Good timing. I am just finishing up a ts3 build for 6s. (even though I was told it couldnt be done he he). I did a fair amount of work to re enforce the transom so I could use a 7.5 lower unit. For now I will go with the bullet drive. Only because I need to do some cutting on my k&b lower to get some weight off. I will start with the bullet dr and see how it goes. For motors I have a scorpion 3226 1600kv. It should be a good match for this size hull. I also have a 3659 edf motor. It is a 1900kv motor though and likely too much for this hull but once I have my hull set up and running well, I will likely try it. as for props i will be keeping it small until i have logged some good data. I couldnt afford a sf 200 for this build so i had to go with a 120. I have a couple of t180.s but there was just no practical way to get it in the bull.Hopefully be testing in another week.

Where there's a will (and four 90deg. fittings + some patience) there's a way to make T-180's fit narrow confines

DSC04308.JPG DSC04381.JPG

[kendt]

Not even that would do the trick on my ts3. The box is as wide as it could possibly be if it is to fit under the cowl. I thought about putting it farther up front in a separate enclosure, and at some point i might. But for right now I didnt want to get into that. I have too many other boats waiting to be finised.I was tying to keep his one as simple as I could. Once i get it on the water and see how it handles the 6s set up I will decide from there if i will go for more power.

[HTVboats]

The TS-3 is very narrow under the cowl. But it does take power well. If you don't go crazy on watts it will perform well. Especially in a SAW. When I got into FE (thanks Z-man) it was as a spec. I though full P would be a natural progression which it is as you use the same 4S packs. Adding HP and going to 3000-4000w motors I learned what amps are all about. 6S or Q brings 200amps peaks down to 135 or so and powers .45 size tunnels perfectly. Staying under 2000w on 6S and you can use .21 size hulls 28-32". 5S on a 1800-2200kv P motor is like a shot of nitrous.
Mic

[kendt]

Thats good info. Thank you.My boat will be just under the 2000 watt mark. Both the motors i have are 1700w rating.I dont have any desire to go past that with this hull, I have a couple bigger tunnels for that. My main concern was the added weight of 6s but all in all i dont think it will be too much heavier than a nitro rtr.I have a cpl more things to do to shave more weight down the rd. For now I will get it running and see how it works.

[er8sr]

Great info. Iam building a7.5 tunnel right now as well I got a few differant motors iam going to play with but I have a castle 240 esc, I was debating on which lower unit to purchase.oh
Also was wondering if would be better to have one big radio box to enclose battery esc and rx and steering servo
Thanks
Bobby

[Grazacind]

There are a few lowers to choose from and I it personal preference to some extent. One big box is the way to I think.

[kendt]

I have bot the 7.5 bullet drive and a couple k&b 's . I personaly like the k&b just because it looks more realistic. The bullet drives are great for the price. Just a word of caution though if you get one. Two of the holes on the top of mine stripped rather easily. Not sure why, I can use longer screws and put nuts on them so not a huge deal. One big box is likely better and less work. Better to make it a bit oversize if you can. Nothing worse than an over crowded radio box. What motors do you have?

[er8sr]

Who has the K&B Lower? I have not found one only 3.5 stuff, I ahve a good variety of motors from from Castle 2200kv to Scorpion Outrunners along with some Hackers. Kv range from 2200, 1400 for motor choices

[kendt]

The 7.5 k&b lowers are a bit harder to come by than the 3.5. You have to kinda get lucky. Sometimes they come up on ebay or intl wtrs for sale.You can also get them diectly from mecoa but its very hit and miss with their stock supply. There is something very cool about outrunners on an outboard. Scorpions are great. My favourite right now for 7.5 tunnels is the turnigy t600. Very resonable price and tons of torque.

[er8sr]

Thanks for the Info what KV?

[kendt]

The one's i have are 1400 kv. On 6s.

[er8sr]

I was going to start with a1600kv out runner.

[kendt]

Yup nothing wrong with that. I have a 1600kv scorpion for my ts3 that im building. Also a 1900kv 3659 edf motor.
I havent done enough testing yet to determine if tunnels like a smaller prop at higher rpms or vice versa but eventually i will.

[er8sr]

I got a VS1 tunnel in the works as well. You guys using balsa or thin ply to do radio box in tunnel

[kendt]

I think most use ply. i used balsa and bass wood. its light and plenty strong for what it has to do,

[kendt]

20130502_143904.jpg

Ready for testing. Not finished cosmeticaly but ready for some trial runs. I decided to go with this motor first rather than the scorpion.

[ChoppyOne]

looks good can ya take a pic with cowl off ?

Dave

[kendt]

20130502_205216.jpg

Here you are. When I get a chance i will clean up some of the extra silicone, although its not nearly as noticable as it appears in the pictures. The lid is just some fiberglass sheet i had laying around.

[er8sr]

Nice. What hull is that? Ts3?

[kendt]

Yup

[er8sr]

7.5 lower? How does that hull handle

[kendt]

Ya its a 7.5 unit. I hope to test it tomorrow. This hull has a good reputation so im thinking its going to work fine. Time will tell though.

[kendt]

Was able to do some more testing today. The 3659 edf motor has turned out to be an awesome choice for this hull. It is a rocket for sure. Still a bit of fine tuning yet. It rides perfectly on the straights but bounces a bit in the turns. Im using a tfl 442 back cut prop. After a 3min run everything comes back just slightly warm.

[er8sr]

What brand motor? 7.5 lower?

[kendt]

http://www.hobbyking.com/hobbyking/s...90mm_EDF_.html

This is the motor. Its a hyper performance bullet drive.

[er8sr]

Nice..