Darin's New N1-Mono Project - WildThing 22, Rev. 002

[befu]

Strakes

Please do!

Attached are two pictures of the aluminum pieces that I used to make my bondo strakes. I just used scrap aluminum, so they are not that long. I need to make new ones, but am considering a couple of new ideas. One is making them out of silicone so it is easier to demold. I would also like to try making a few out of a urethane liquid plastic. Might be better than bondo. will have to try I guess.

Main thing is, before I make a new mold, how big should they be? I also molded them so they were flat when mounted on the bottom of the hull, 16 degrees. I thought if a strake went negative on its angle, it prevented the boat from being considered a mono hull in the IMPBA/NAMBA. Has that changed? Anyways, here are the pics. The bar is 1/4 x 1 aluminum.

Brian

P.S. The pics of the boat is the other thing I am still working on. The bottom is plenty stiff enough, but having a problem with the vacuum bagging. I am sucking too much resin out of the laminate and ending up with voids in the layup. Not huge, but you can see some spots in the bottom that need filling and the corner strakes have voids also. Weight wise, I think it will work out. The hull with a strong transom is 2.5 oz. The layup is three layers thick in the rear, two or three up front. Still working on it, but have taken some time off lately for family.

[Brushless55]

Power rules are pretty simple:

N-1 Any ROAR-approved stock .05 motor as defined by current ROAR
parameters. Power Limits: Up to 7.5 Volts nominal, any
chemistry. Maximum of 2 packs in parallel. Maximum capacity of
10,000 mAh.

Generally speaking, very few people race these any longer. Used to be 27T brushed, but now we're playing with the 17.5T BL. I think, if I read the ROAR rules correctly, the 21.5T is legal as well.
The two hull types that seem to still survive, mostly on a SAW or 2-Lap time trial basis, are N1-Mono and N1-Hydro.

If you have any legal tricks... feel free to PM me with the info!

Darin, is one motor better than the other for this class of racing?

[Darin Jordan]

Darin, is one motor better than the other for this class of racing?

I don't have first hand information to confirm this, but I would have to suspect yes. Those motors made with better quality copper, cans, bearings, magnets, etc., would have a slight advantage when you are talking about this type of very limited motor.

[Darin Jordan]

Got the strakes finished.

About a week's worth of evenings glueing, sanding, filling, sanding, filling, and sanding, and I was able to primer and paint the bottom tonight.

Will let it setup and cure for a few days, then get back to installing the new stuffing tube and cable, and we'll be back in business.

[Brushless55]

I don't have first hand information to confirm this, but I would have to suspect yes. Those motors made with better quality copper, cans, bearings, magnets, etc., would have a slight advantage when you are talking about this type of very limited motor.

oh sorry, I ment between the 27t and the 17.5t
what do you prefer?

[Darin Jordan]

oh sorry, I ment between the 27t and the 17.5t
what do you prefer?

Well... you are talking about a brushed motor (27T) vs. a Brushless (17.5T)... The 27T can be made to turn quite a bit more RPM out of the box. Depending on which 27T you use, I have some that turn as high as 35K on the bench with a 2S pack.

However, all of the issues associated with running a brushed motor in a boat apply. Hard on brushes, no real way to cool, etc.

The 17.5T BL motors have quite a bit of torque, and have a wide array of controller options. They are maintenance free, can be can cooled, etc. They do, however, take a whole different approach to making the boat go. They are only 2200KV, so around 18,000 max on a 2S pack. BIG props, or figuring out how to convert the torque to RPMs or otherwise get their RPM range up seems to help.

I wouldn't be doing this anymore with brushed motors, personally. I think we've seen what they are capable of, and now it's time to move up and on.

VERY few race the class in heat racing these days. It's just too slow. Even the fast boats only do 33mph at this point, which is quite a bit faster than they used to be. That is a SAW speed, by the way....

[befu]

Roar motors and strakes

The other item on brushless roar motors and racing is the price. How much do these things cost? I think I have seen them for $35, but others have been twice as much. What could you setup a Roar boat for concerning motor/esc? Are there cheaper options to play around with?

I have a turnigy 3650-2300 in my 24" WT, but run it on 3s. Would that motor on 2s be close to a roar motor, just slightly higher kv. Size is the same, but just for comparison, not for sanctioned racing.

Besides being slower, if the above holds true, you have an expensive power system in it that could be beaten by a $12 cheap outrunner and a $15 china ESC. People do not like paying more to go slower, so that is one huge hurdle. But I do like the concept of a limited power system so it is up to driving and tuning (which most races are anyways, but a cheaper investment would be nice for some)

I still think the gearing is the way to go with being limited to 2s and 2200kv. Smaller prop and high rpm on it to help control the prop walk and torque.

Darin, how did you end up making the strakes? Looks good.

Brian

[Darin Jordan]

Besides being slower, if the above holds true, you have an expensive power system in it that could be beaten by a $12 cheap outrunner and a $15 china ESC. People do not like paying more to go slower, so that is one huge hurdle. But I do like the concept of a limited power system so it is up to driving and tuning (which most races are anyways, but a cheaper investment would be nice for some)

You guys need to understand that N1 is a DEFINED power specification. It SPECIFIES that you use a ROAR Stock motor... Period. That's the challenge to the class. If you want to go faster, you go run N2....

I still think the gearing is the way to go with being limited to 2s and 2200kv. Smaller prop and high rpm on it to help control the prop walk and torque.

I wouldn't disagree. However, with the new ESCs, that may not be the only way to get the RPMs up.

Darin, how did you end up making the strakes? Looks good.

Brian

Laid down birch strips, sanded to shape, filled with filler, sanded a few more times, then painted. Pretty easy way to get consistantly shaped strakes.

I may try the form and filler idea on the next set.

[befu]

You guys need to understand that N1 is a DEFINED power specification. It SPECIFIES that you use a ROAR Stock motor... Period. That's the challenge to the class. If you want to go faster, you go run N2....

Oh, I do understand that it is a specified power class, not arguing that. I was just talking that if someone wanted to try running "similar" power for testing or a comparison, that is all. Not trying to change the class or push rules.

I wouldn't disagree. However, with the new ESCs, that may not be the only way to get the RPMs up.

I heard something about a "boost" function on some brushless ESC's.

Laid down birch strips, sanded to shape, filled with filler, sanded a few more times, then painted. Pretty easy way to get consistantly shaped strakes.

I may try the form and filler idea on the next set
I want to make a new mold for strakes on my 24/22" mono's. I wasn't sure if I should try to make the next set larger or stay the same. They are definately pretty fine right now. Of course, with using an aluminum bar, it is easy to machine two options by using both sides of the bar. Mine will be for a 16 degree mono and yours looks deeper than that, but if they would work for you, you are welcome to some strips. I appreciate your guidance on when I was setting up my little mono and it would be a small way to show that appreciation.

Still working on that mono. Had child #5 born last week so I have been a bit busy at home and work is busy right now as I have 5 weeks to merge another factory into mine, so I have my core leadership here split between facilities working on that acquisition! Busy, but it is a damn good life the Lord has given me!

Back to work, Brian

[Brushless55]

Well... you are talking about a brushed motor (27T) vs. a Brushless (17.5T)... The 27T can be made to turn quite a bit more RPM out of the box. Depending on which 27T you use, I have some that turn as high as 35K on the bench with a 2S pack.

However, all of the issues associated with running a brushed motor in a boat apply. Hard on brushes, no real way to cool, etc.

The 17.5T BL motors have quite a bit of torque, and have a wide array of controller options. They are maintenance free, can be can cooled, etc. They do, however, take a whole different approach to making the boat go. They are only 2200KV, so around 18,000 max on a 2S pack. BIG props, or figuring out how to convert the torque to RPMs or otherwise get their RPM range up seems to help.

I wouldn't be doing this anymore with brushed motors, personally. I think we've seen what they are capable of, and now it's time to move up and on.

VERY few race the class in heat racing these days. It's just too slow. Even the fast boats only do 33mph at this point, which is quite a bit faster than they used to be. That is a SAW speed, by the way....

Oh I thought there were brushless 27t motors that you could chose or run a 17.5t motor in this class

either way spending the extra cash for the better motor looks well worth the price

[Darin Jordan]

Oh I thought there were brushless 27t motors that you could chose or run a 17.5t motor in this class

That's exactly right... you can still run the 27T Brushed motors... They are also "ROAR legal Stock 05 canned" motors....

[Brushless55]

That's exactly right... you can still run the 27T Brushed motors... They are also "ROAR legal Stock 05 canned" motors....

so they don't have 27t brushles motor you could run vs. a 17.5t brushless motor

[Darin Jordan]

so they don't have 27t brushles motor you could run vs. a 17.5t brushless motor

No...

Here, you can understand the rules better by reading this: http://www.roarracing.com/downloads/..._Rule_Book.pdf

See section 8.5 and 8.8. You are looking for the references to "Stock" motors. These will be defined as a specifically approved 27T Brushed, or a specifically approved 21.5T or 17.5T Brushless.

You can see which motors are approved by looking at one of these two lists:

Roar Approved Brushed Motor List: http://www.roarracing.com/approvals/print_smotor.php

Roar Approved Brushless Motor List: http://www.roarracing.com/approvals/...lessmotors.php

Again, only those listed for "Stock" (Stock, Rebuildable Stock, Stock/17.5T Spec, Stock/21.5T Spec) classes are allowed in N1.

[Darin Jordan]

Finally got her done!

Moved the motor back. Got rid of the .047 wire and replaced it with .098 flex. Installed three Boca 1/8"ID x 1/4" OD bearings in the Fuller's strut with the aft one being flanged. Fabbed and installed some trim tabs as well, and added hard points to the mounting for the turn-fin (was just double-back taped on before).

I went a little bit crazy with my buffer... polished up all the hardware, including the coupler. All the transom mounting screws are aluminum 4-40's, by the way... every gram counts. I even polished the propeller shaft. The drivetrain is SUPER smoothe and drag free on this one!

I now have room for any battery setup I wish to use. Boat weighs 1lb 7.6oz RTR minus battery. Just a hair over 2lbs with a full 5000 mAH 2S 40C hardcase pack. With this pack, the balance point is back at about 29% with the cells fully back, and the ESC where shown. LOTs of room for adjustment. Should be solid!

[Brushless55]

that looks cool!