turn fin tuning

[rc_speed]

Hello,
I bought my first boat, a UL-1, and am going to race it at the local club. I have changed the prop to the aquacraft recommended L38X55. I am using Zippy flightmax 30C 5000 lipos. Everything else is stock.
On the test and tune day, I flipped it one time. Now I see a couple of hairline cracks at the seams. I would include a picture, but I don't think you would be able to see the cracks in it. The cracks don't seem big and they don't appear to be deep. However, when I finished running for the day (4 runs), i pulled the plug out of the back and dumped out about 1/8 cup of water. Is this normal?
What is the best way to seal the cracks? I bought some marine epoxy. I thought I would mix it up and then spread a LIGHT coat along all the seams of the boat.

Now for my other question.
I bought a replacement aluminum turnfin that is thicker than the stock one, but is straight. I did this on the recommendation of a fast guy at the club. He said the stock prop can bend under the forces of use.
Can somebody explain to me how to tune the turn fin?

thank you,
tim

[longballlumber]

On page 7 and 8 of the manual there is some info on tunning the strut, rudder, and turn fin. I would suggest starting there to establish the basics. Once you've done that, test test test. While testing keep notes on what you changed and how it affected the performance and handling of the boat. Only change one thing at a time. If you make more than one you won't know which change had the most affect on the performace.

http://manuals.hobbico.com/aqu/aqub20-manual.pdf

Most important, HAVE Fun!!!

Later
Mike

[Capt. Crash]

Hello,
I bought my first boat, a UL-1, and am going to race it at the local club. I have changed the prop to the aquacraft recommended L38X55. I am using Zippy flightmax 30C 5000 lipos. Everything else is stock.
On the test and tune day, I flipped it one time. Now I see a couple of hairline cracks at the seams. I would include a picture, but I don't think you would be able to see the cracks in it. The cracks don't seem big and they don't appear to be deep. However, when I finished running for the day (4 runs), i pulled the plug out of the back and dumped out about 1/8 cup of water. Is this normal?

No...you should have NO water in the hull at the end of the day. If it's not leaking in those cracks, it could be leaking around the stuffing tube where it enters the hull....mine did.

What is the best way to seal the cracks? I bought some marine epoxy. I thought I would mix it up and then spread a LIGHT coat along all the seams of the boat.

I have great luck running thin CA glue into those hairline cracks.

Now for my other question.
I bought a replacement aluminum turnfin that is thicker than the stock one, but is straight. I did this on the recommendation of a fast guy at the club.

I tried the straight fin and didn't like it, went back to the stock one.

He said the stock prop can bend under the forces of use.

This should not be a problem unless you thin it down too much.

Can somebody explain to me how to tune the turn fin?

That is down by adjusting it up or down per the instructions in the manual. I just leave mine all the way down.

thank you,
tim

Hope this helps some

Crash

[BakedMopar]

I lost my original plug and the replacement I got was much harder. I now have had water in the hull too. Took that out and covered with tape. Now my hull is again watertight.

[rc_speed]

ok, thanks. I spread some super glue in the tiny cracks that I got. I smeared it along some of the seams. I also spread a bead of epoxy around the joint where the prop tube enters the bottom of the hull. If it still gets water in it, I will try taping over the plug hole
I have my first race on sunday, so I will find out how it does then.

[Capt. Crash]

It's also possible that it's leaking around the bolt holes on the transom or turn fin sponson. I always pull my bolts and dab some clear RTV sealer around the holes and under the brackets then retighten the bolts.

Crash

[Jeepers]

.
. He said the stock prop can bend under the forces of use.

I think you meant the turn fin.

and yes the stock plastic prop can and does flex.

[rc_speed]

oops, I meant turn fin. thanks for the correction.

I saw somewhere that the boat can face 3-4 g's of force during a turn in a race. This can equate to a force on the fin of 3-4 times the weight of the boat on that fin.

I tried to order better fins from kintecracing, but they are out of stock and the replacement production is going slowly. In fact, they refunded my money and told me to re-order them when the web site says they are in stock.

Is there somebody else that makes a replacement turn fin for a UL-1 that is better than the stock one? I know I can make my own, but I would rather buy one.

thanks,
tim

[Diesel6401]

oops, I meant turn fin. thanks for the correction.

I saw somewhere that the boat can face 3-4 g's of force during a turn in a race. This can equate to a force on the fin of 3-4 times the weight of the boat on that fin.

I tried to order better fins from kintecracing, but they are out of stock and the replacement production is going slowly. In fact, they refunded my money and told me to re-order them when the web site says they are in stock.

Is there somebody else that makes a replacement turn fin for a UL-1 that is better than the stock one? I know I can make my own, but I would rather buy one.

thanks,
tim

Scroll to the bottom, 3 to choice from. http://www.offshoreelectrics.com/products.php?cat=67 stock one is their as well other two have similar dimension except stock is .01" thicker & .15" shorter.

[Jeepers]

oops, I meant turn fin. thanks for the correction.

I saw somewhere that the boat can face 3-4 g's of force during a turn in a race. This can equate to a force on the fin of 3-4 times the weight of the boat on that fin.

I tried to order better fins from kintecracing, but they are out of stock and the replacement production is going slowly. In fact, they refunded my money and told me to re-order them when the web site says they are in stock.

Is there somebody else that makes a replacement turn fin for a UL-1 that is better than the stock one? I know I can make my own, but I would rather buy one.

thanks,
tim

3-4 g's maybe more, (I don't know) I read someone data logged 7g in a UL1 powered rigger.

I don't know of anyone else that makes a replacement fin, make your own, I use stainless but it is a pain in the A$$ to cut and work.

[Diesel6401]

3-4 g's maybe more, (I don't know) I read someone data logged 7g in a UL1 powered rigger.

I don't know of anyone else that makes a replacement fin, make your own, I use stainless but it is a pain in the A$$ to cut and work.

7gs, really? that's nuts. I wouldn't have ever thought a rc boat could pull that. 3-4 is a good bit, but 7 WOW you figure a military jet pulls around 10 in high g turns. Impressive

[Jeepers]

Scroll to the bottom, 3 to choice from. http://www.offshoreelectrics.com/products.php?cat=67 stock one is their as well other two have similar dimension except stock is .01" thicker & .15" shorter.

yep and they all bend under hard cornering. in my opinion they flex to much to give precise cornering.

Tim you could add some bracing like in this pic, and attach it to the side of the hull.

[Jeepers]

7gs, really? that's nuts. I wouldn't have ever thought a rc boat could pull that. 3-4 is a good bit, but 7 WOW you figure a military jet pulls around 10 in high g turns. Impressive

Diesel here is the post I saw on the rigger, the data was logged by Eagle tree system

http://www.rumrunnerracing.com/feforums/showthread.php?t=30136&highlight=JAE

[longballlumber]

I would rather buy one.

thanks,
tim

Tim,

I have one of the kintec straight fins I can sell. It's brand new, never used. Let me know if your interested.

Later
Mike

[Diesel6401]

Tim,

I have one of the kintec straight fins I can sell. It's brand new, never used. Let me know if your interested.

Later
Mike

If he doesnt take it I will. I want to try it on my 7xl setup.