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set up for dumas .21 nitro ( porposing)

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set up for dumas .21 nitro ( porposing)

Old 07-03-2005, 10:39 AM
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rcnutman
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Default set up for dumas .21 nitro ( porposing)

hi people,
Me and my buddy just each bought dumas hot shot.21's.....We took his out this mourning and the boat was purposing like a dolphin.[&:][:@][:'(]
I figured if was the height of the motor so i lowered it. This did nothing. I tried to raise it,same effect,nothing. So the i figured it was the angle of the motor. I raised the motor to the farthest positave and negative angle......This also had no effect..The boat seemed to stop porposing a little bit when it hit half throttle.....I messed with this a bit and the boat wound up flipping over on a wind ripple.....
Im not so impresses!!!!!!!!! Is it the smallness of this hull, I dont know what else to do??????
If any of you guys have the instruction manual as far as tips in setup can you post them for me?? Neither of us have the instructions..
Maybe one of you could take a pic for me of the rear of the boat. A close up of the motor angle and height of the motor mount??
Any help would be appriciated ....
thanks ( i did not have this problem with my prather lap cat??)
Old 07-03-2005, 03:04 PM
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biteme
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Default RE: set up for dumas .21 nitro ( porposing)

Perhaps try adjusting the balance, more weight forward or aft. Maybe even some trim tabs. (honestly I'm not even familiar with the boat, gotta pic?) Hadda friend with a similar problem; is your boat fairly short?
Sean
Old 07-03-2005, 04:02 PM
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Ron Olson
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Default RE: set up for dumas .21 nitro ( porposing)

I'm guessing that it's the ABS version. I haven't seen too many that don't porpoise at low speeds. At their length, they really aren't up to todays standards as they are a little on the short side. The ABS version came out with the sponsons too shallow as opposed to the wood kit version. They need an extra 1/8" of wood added to the bottoms, preferably balsa because of the light weight.
Keep the motor angle pretty much neutral for now and the motor height should have the centerline of the prop shaft at slightly above the bottom of the sponsons. If you need to add weight to the nose, about 4 oz. ought to do it.
Old 07-03-2005, 04:02 PM
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rcnutman
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Default RE: set up for dumas .21 nitro ( porposing)

hi there,
Yes, i did just add a few pieces of nose weight to the bow. The boat is a dumas tunnel hull I have a pic of mine ( we have only run his )
The boat is pretty light and is only 24 inches long...... I dont have any set up directions on the boat because we both em off ebay. If somebody knows the cg please post it... I will head out in a few minutes and try the boat with the weight on the nose..well see[8D] what happens. I have the prop shaft about an 1/8 inch below the bottom of the sponson..And the motor is a 0 degrees of pitch.......
I hope it works!!!!!!!
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Old 07-03-2005, 04:15 PM
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rcnutman
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Default RE: set up for dumas .21 nitro ( porposing)

hi there,
I figured the shortness of the hull had somthing to do with it. I had a prather lap cat and it didnt do any porpoising..This boat did it really bad at like quarter throttle it was out of control[:@]..When I went to half throttle it stoped for a few...I tried to go to full throttle and after 3 secomds the boat did a really bad porpoise and flipped ( not a blow over ).....

I added 7 ounces to the nose and i raised the motor a little so it looks like the shaft is even with the sponcen bottom.......
man i hope i have a little more luck tonite,,
thanks for you info guys!!
Old 07-03-2005, 10:56 PM
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rcnutman
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Default RE: set up for dumas .21 nitro ( porposing)

I just got in from running my boat.....I have to say that the boat likes to do a lot of bouncing from 1/4 to 1/2 throttle!!!!!!!
This time i waited till the water was glass. The boat went fine as long as i keep it a 3/4 to full throttle ( which aint a bad thing)......
I was impressed........The boat goes like a bat out of hell!!!!!!!!! It was very stable in the turns for the most-part..The baot turns a lot beter to the right!! I was at full throttle and a hit a wind ripple and the boat did a cart-wheel[:'(]..........Maybe ill go for a little negative angle on the motor........It kinda stinks that i have to run it in glass water only[&o].. two tanks through the boat and 3 flip overs....O well thanks for the tips guys!!
Old 07-03-2005, 11:29 PM
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Default RE: set up for dumas .21 nitro ( porposing)

Keep dialing it in! When you get it where it handles fine, mark the settings on the transom and motor mount if possible so if you try any changes or remove the motor for any reason you can quickly find the sweet spot again.
I'm waiting for OB Nut or krpnova to see this, they know this boat better than I do. My experience with this hull was working on 2 other friends boats. One of those we had finally gotten his dialed in and it was all that I could do to get him off the water. It was 10:00 PM and the park was closing.
Old 07-04-2005, 07:30 AM
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Default RE: set up for dumas .21 nitro ( porposing)

thats a good idea. I will mark my settings.....we sat at the lake in my boat for 1.5 hours last nite waiting for the glass water!!!!
It finally came after 830....we only had about 30 min of light. But it was a great 30 mins..........I would have stayed for another tank but my boat did a 180 flat on it top.............I figure that was a sign for me to call it a nite.....I think I will run my boat a few times...I have it listed on rcuniverse. I want to get top speed tunnel hull when they come out....Its a nice looking boat...you cant beat the price!!!!!!!!!!! I rhink I will have better luck with the 30 inch length hull instead of a 24 inch!!!!!!!!
Old 07-04-2005, 09:07 AM
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Default RE: set up for dumas .21 nitro ( porposing)

They're already out at a few hobby shops or else they must know somebody as Tower is showing them as arriving soon. They're only showing them in 4 colors but there should be 2 more coming out, teal and tan.
BTW, if you look around on the Tower site, there is an online coupon that you can use to knock another $20.00 off the price!!!!
Old 07-04-2005, 02:55 PM
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Default RE: set up for dumas .21 nitro ( porposing)

hey ron.........do you happen to know of a online place that has these in stock rite now????????[8D]
Old 07-04-2005, 04:49 PM
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Default RE: set up for dumas .21 nitro ( porposing)

One place might be www.philshobbyshop.com in Fort Wayne, IN. Call the main store or e-mail them as it isn't on their site right now. This is where krpnova works at so contact Bob at the main store if you call. Your LHS may be helpful in getting one also as most can get Aquacraft boats.
Old 07-05-2005, 12:33 PM
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Default RE: set up for dumas .21 nitro ( porposing)

Most likely the purposing due to one of the following.

- The engine is too far to the transom - try moving the engine up.

- The strut angle is pointed up too far - lower the angle of the strut (where the prop is) to face straight out with a slight down angle.

This should fix your problem.
Old 07-05-2005, 04:54 PM
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biteme
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Default RE: set up for dumas .21 nitro ( porposing)

yep, I thought you might have a shorty like that. the shorter the boat is, the harder it is to find the sweet spot (cuz the spot is smaller too.) The 30 in boat will probably not be so finicky. Also realize that the type of hull is not made for any type of bad weather; it needs glass. If you want something that will handle weather better (for those days when the wind is blowing) add a deep V, or even a tunnel cat to the fleet. the eventuality of having several boats will give you the ability to choose the right boat for the right situation. Definately keep trying...the time you put into it will be well worth it (even if you can't make the little boat run better).
Old 07-05-2005, 05:22 PM
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rcnutman
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Default RE: set up for dumas .21 nitro ( porposing)

I actually have a w-hobbies super-g and a prather funcruiser......I used to have a 27" lap cat...It was my first boat. I only ran it a few times and sold it....figured maybe in a few years i will be ready for a tunnel......After having the big vees.........I started to miss the tunnel hull......I actually put mine together today and took her to the lake!!!!!!!!! She went the same as my buddies[:'(].......I got it to humm on the straight away and holy high dive,,,,,the boat did a 320 rite down under.......It went close to a foot underwater.........Once I got over to it I noticed that the stupid hatch-cowl came off and was slowely sinking to its dume.........down she went bye bye[]......( (not sure why that cowl was a velcro instead of tape. bad idea).....I called dumas and the new cowl is 17.00..............Im all set, time to say bye bye to the little boat that could'nt.....I will not spend any money on her. I am gona sit tite till the top-speed comes out......i think it will be easer to find the swet spot on a 30 incher verse a 24........
Old 07-05-2005, 08:54 PM
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Default RE: set up for dumas .21 nitro ( porposing)

When you get the TS 2 or any boat that has some kind of hatch or cowling, add some kind of floatation to it. I found that out the hard way a couple of weeks ago myself. On my new Sport 40, it has a rear hatch on it. The boat decided to go skyward at around 60 MPH and the hatch that I thought was securely mounted got ripped off when it landed. I got a replacement piece and you can bet that it will have some foam attached underneath! On my tunnels I would use some pipe insulation held in place with double-sided tape as I have lost those a few times also.
Old 07-06-2005, 09:07 AM
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Default RE: set up for dumas .21 nitro ( porposing)

A modified ABS Hot Shot Sprint held NAMBA ( I think) SAW record for 10 years. One needs to work on that boat to get it to run right. I was never able to myself. And I had lead in the front and back. Mine bounced side to side, not back / forth like you described.

Here's my current wood version:


Vid:
[link=http://www.rcflix.com/photopost/data/506/6122.mpg]Hot Shot Sprint vid[/link]

Boat is running with a K&B 3.5 SS motor.

CG should be between 28% - 33%.. Can't go wrong with the TS2 either...
Old 07-06-2005, 09:25 AM
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Default RE: set up for dumas .21 nitro ( porposing)

Oh yea, my wood boat has no extra weight added. It balanced out great as is.. Boat was built with foam instead of 1/4" frame rails to support the sheeting.
Old 08-03-2005, 10:13 AM
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Default RE: set up for dumas .21 nitro ( porposing)

Hi everybody, If you want the number to Phils Hobby Shop, to ask KRPNova about your setup its 260-426-5056, and we have the Top Speed 2's in as well

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