Originally posted by bentwings
Guys, I put a boost tab on our Ziroli P-51 rudder and I can tell you it is a royal PITA. To actually make it operate is the next level followed by truley functional. Keep in mind this is a 100" wing span plane at about 40 pounds with a 5.8 motor. I I removed the the functional part and made it look real instead. The 5.8 destroyed it the first run up anyway.
Having flown the wings off our Z corsair (94" wing) over the last 9 years and replaced a number of damaged servos, my personal opinion is that you are really asking for some disapointment. I have spent considerable effort to prevent flutter on all control surfaces and have been very successful using more or less proven methods..ie tight sealed surfaces, husky linkages, balanced control surfaces, all gaps are tightly sealed, powerful servos with good leverage. this plane has been on countless near vertical dives (bomb runs) aerobatics, nasty winds, encounters with flying and non flying objects. plus more than a few very rough landings. through all of this it still flies very well. I have trashed at least 8 75oz or better servos in flight. several flights were obviouly flown with one servo stripped or jambed with no loss of control. One rudder servo 135 oz (F- giant scale)was destroyed when the gear collapsed and it ground looped snagging the tail wheel on a rock. One 135 oz elevator servo failed after a hard landing. the whiplash of the tail hitting the ground caused the elevator to cycle opposite the command. I would not have any objection the the scale detail of boost tabs, they certainly will look nice, but I would not depend on their functional effectiveness to be able to cut back on the servo size for a few dollars. The second factor to consider is weight. My rudder and elevator servos are very near the CG to keep from having to add anymore weight than necessary to the nose of this plane. Still have 2-3 pounds. Now if you are building a smaller plane weight becomes more important. Keep in mind that weight at the tail take about 4 to 1 balance at the nose. One oz in the tail takes 4 oz in the nose so you have added 5 oz to the plane for 1 oz of detail. I think I would make these look functional and leave the servo do the driving.
This is just my opinion and not any criticism of creative thinking.
goos luck
bentwings
Sorry to hear about your back luck with them, but I have never had any problems with them yet. I started using them way back in the mid 70's
If they are made right, they will work, that is a sure thing. Why do you think all large aircrafts have them.
Sealing gaps won't stop flutter it will make the controls tighter. No slop, and balanced surfaces will stop flutter to a degree.
Were you flying this airplane at a much greater speed then recommended?
To tear off the Boost tab on the ground, maybe the engine was vibrating too much.