• If you are new to GiantScaleNews.com, please register, introduce yourself, and make yourself at home.

    We're 1st in Giant Scale RC because we've got the best membership on the internet! Take a look around and don't forget to register to get all of the benefits of GSN membership!

    Welcome!

Stabilizer Design Discussion.

Snoopy1

640cc Uber Pimp
Sorry if I am a little long winded but would like to explain why this interested me. Been in the hobby for well over 30 years. Built a fully moving stabilizer about 20 years ago. It works but not well. Moved the pivot point of rotation back and forth and eventually came up with a location that worked. But the servos that we had at the time were at most 125 oz-inch and were not digital, the centring was not strong. Just getting interested in 3D and have 2 plans so far. looking at the stabilizer on the 2 planes more than 60% is elevator. My question is would the elevator not be more effective if the whole stabilizer would rotate. (Like on some jet planes). With the power and centering of today's servo would it not be a better design.
 

Terryscustom

640cc Uber Pimp
Flutter would be the main issue with a full actuating stab. It would require two servos in a push-pull configuration and a VERY strong structure and linkage system not to induce catastrophic flutter.
 

Snoopy1

640cc Uber Pimp
Flutter was one of the main problems when trying to this. By moving the pivot point ahead it stopped that problem but then the servo was not strong enough to get a decent amount of deflection. With the servos of today this should not be a problem. I agree with you Terry the drive system is not easy but doable. But the design thought is about 3D where every thing low and slow where I believe that this design could have some merit.
 

Spats

100cc
@Terryscustom is right. The configuration would be to much. The best thing for a really powerful stab would be to just make the stab itself barely big enough to hold the servo and 90% of the stab would be the elevator. But not sure its needed. All of my plane already have a huge elevator that does plenty for me.
 
okay so this is a blast from the past... look up the leo loudenslager shark... it was a full scale airplane that would have changed modern aerobatics if he hadn't been killed on a motorcycle.. it has a cruciform tail and once the elevator and rudder hit 45 degrees of travel the entire surface would move to 60 degrees... on that other terrible site someone actually built a 40% version with the moving surfaces. pretty neat and it worked...
 
this is the full scale.. could you just imagine???
 

Attachments

  • Shark 4.jpg
    Shark 4.jpg
    130.7 KB · Views: 409

ghoffman

70cc twin V2
On full scale planes (like F-16) the center of pressure is slightly aft of the pivot on the stabilator. This is something that you have to trade off. The closer they are to equal, the less force it takes to move it, but the more likely it is to flutter.
 
Top