PDA

View Full Version : Trim tabs on cats?


dmitry100
08-31-2015, 07:31 PM
Hey guys,

Just came across this and found it odd... never seen anyone do this on a cat... only on monos.
Have any of you tried this before?

http://www.rc-silverboats.de/RC-Boote/Ordner%20Matthias/Bilder/HPR06/HPR06-49.jpg
dasboata
08-31-2015, 07:44 PM
I did with bad results, that one looks way to low with not alot of adjustment left ?? The best luck I had with trim tabs on a cat was in the tunnel on the transom of the boat it did help but that was way back when I was a newbie LOL
Rocstar
08-31-2015, 08:22 PM
The best luck I had with trim tabs on a cat was in the tunnel on the transom of the boat it did help but that was way back when I was a newbie LOL
Some full size race cats do it. I've never had a reason to try it on an R/C boat but would be interesting.

http://i339.photobucket.com/albums/n454/tofly95/CECF71D4-956B-4687-87B1-E12410EFBFA7_zps6efziwb4.jpg
Fluid
08-31-2015, 09:31 PM
A fellow club member and I ran tunnel tabs on several of our SAW cats, they do work but need good speed to be effective. They should not be needed aft of the sponson ride surfaces. Ours were adjustable but not radio controlled.


.
dmitry100
09-01-2015, 01:18 PM
I got this pic from an HPR build log... http://translate.googleusercontent.com/translate_c?depth=2&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&u=http://www.rc-silverboats.de/Baubericht/HPR115.html&usg=ALkJrhgzvzBoD1xZarCnIC1qFNNgnXRYjg
dmitry100
09-24-2015, 03:26 PM
Fluid: What do you mean "not needed aft of the sponson ride surfaces"? What kind of cats did you use them on?
Fluid
09-24-2015, 05:42 PM
They were used aft of the cat's tunnel to deflect air exiting the tunnel. Trim tabs on the sponson transoms of a cat should not be needed, they just add drag. The correct way to trim a cat is through CG and strut adjustments. The cat would have to be very poorly designed to "need" trim tabs on the sponsons.



.
blowNover
09-25-2015, 12:54 AM
Look at the picture Joel posted. Look where that it. It's not so much of a "trim tab" as it is a aerodynamic stabilizer. As you would see on a super car. It's there to direct airflow not water. That being said I have seen true trim tabs on plenty of full size cats.
srislash
09-25-2015, 01:11 AM
What ever happened to skullcrackin's take on this. He was doing a 'drop down' in the rear portion of the tunnel to disrupt the airflow.