SD3 33" CG

[Flyguy55]

I'm laying out a 3.5 SD3 nitro hull for electric oval racing . Strut and Rudder are from Seaducer .Can some of you that have good running 3.5 SD3 hulls measure and let me know where your CG is ? With everything in it , its going to weigh 7 to 7.5 lbs .

Thanks , Dick Roberts

ABQ NM

 

[properchopper]

I'm laying out a 3.5 SD3 nitro hull for electric oval racing . Strut and Rudder are from Seaducer .Can some of you that have good running 3.5 SD3 hulls measure and let me know where your CG is ? With everything in it , its going to weigh 7 to 7.5 lbs .
Thanks , Dick Roberts

ABQ NM

Dick, When I began to set up my DF 33 some time ago, I talked to [the late and lamented] Ron Green about cg. He told me that he set up his SD at @ 8 1/2 " from the back. { I tried it on the DF and it was blowover city !} 'tho Ron did know his SD's. Hope you get it setup before next week; see 'ya in AZ, Buddy !

I just remembered that Tyler Gerrard ran a FE 'Ducer ; PM him at racemechanix on OSE or RRR. Or should I be helping you kick my butt in P-Mono ? lol

 

[Andy Greene]

Chris Harris and Ron where very close- he may be able to help you,

MrHammerHead on this board.

seems to me like Properchopper said- Ron always used a measurement from the rear of the transom forward, kinda the same way a nitro versions engine is placed.

Andy

 

[RaceMechaniX]

Dick,

I tried running a SD3 P-mono with poor results. I had the CG too far forward which made the hull very wet. The DF is a much better hull in my opinion especially for FE. I have pics of both my set-ups here on IW.

Here is the SD3:SD3 P-mono

Here is the DF33:DF33" P-mono

The ducer had potential, but you cannot set it up like other boats. The FE version is a lot heavier than a .21 powered nitro boat if you run 2P.

Tyler

 

[Doug Smock]

8 7/8" to 10" If you can get that moving your cells fore and aft, you'll be abe to make her happy in oval trim.

IMO 4x 2s is the way to go with the cells outside the rails.

Good luck!!

Doug

 

[Flyguy55]

I'm hoping some of the nitro guys will jump in here . Where do they have their CG .

The boat has 4" rails . The best lipo position seems to be with 4 - 2S 4500 PQ pacs in a 4S2P with one pack out side the rails on each side, and another inside vertical beside the motor mount in a 4S 2P arangment. I pretty much can move the lipos anywhere in the hatch opening .

I have the motor in the mount and it all fits . The hardware is mounted. When I have the CG info I can istall the motor mount and finish the flexshaft housing .

Hmmmm maybe I can race it at WW V . naaaa , Steve is out of cooling jackets .

I'd like to center the motor on the CG if possible. It won't be funished for WWV . I think I'll have enough power to run it wet like the Nitro Guys do. I know Ron and Doug make them fly for SAWs

I'm looking at race water.

 

[RaceMechaniX]

Dick,

What I was trying to say in my post is that you cannot go buy what a nitro set-up is. I still have a SD3 nitro boat that runs well, but the best nitro 21 SD3's are the 29" version not the current 33". The 33" needs very rough water to run at competitve speeds. I made this mistake setting up my FE boat like my nitro and it was just too wet even with 4S2P/hydra 240/neu1521 1.5D power. Make sure you can move the CG back to 8". Start at 9" and move the batts backward till she loosens up.

Where is your motor? Up front like this:

 

[Flyguy55]

I haven't installed the motor mount . I can install it any where in the hatch opening. Tell me where the CG is on your nitro boat . Thats the info I'm looking for. If I center the motor on that CG , I can move the lipos the full length of the hatch opening to adjust the CG.

I had a 29" with 1515 in it and it was squirrel. I think you would get a lot of argument in this country on which is the best boat.

Dick

What I was trying to say in my post is that you cannot go buy what a nitro set-up is. I still have a SD3 nitro boat that runs well, but the best nitro 21 SD3's are the 29" version not the current 33". The 33" needs very rough water to run at competitve speeds. I made this mistake setting up my FE boat like my nitro and it was just too wet even with 4S2P/hydra 240/neu1521 1.5D power. Make sure you can move the CG back to 8". Start at 9" and move the batts backward till she loosens up.
Where is your motor? Up front like this:

 

[M@MRacing]

My 33" sd3 runs well on both rough and smooth it is all in the set up