warped disk on horizontal stabilizer

B

bobgoodman

New member
so, i quickly noticed that at cruise i need to rest my foot on the right rudder pedal to make my cruisemaster fly straight. i have been living with it for over a year now, but have been looking for a reason. i did some measuring, and my the left tail roundrel (or whatever you call the discs on the end of the stabilizer) is pointed to the right and is warped a little bit. i have tons of documentation from the previous owner but nothing about this.

it looks to me like the fabric will have to be cut to remove it. if i do remove it, can it be straightened? how? is there any adjustment? i was also thinking how convenient it would be to put it on a hinge and make it into some rudder trim system somehow. it seems to me to be pointing to the right and warping inward on the bottom. the other one is solid straight and in line.

im sure it must be slowing me down too. i'm only getting 170 kts at 22 square..on 12 gph. just think how fast it would be if i just took them both off.

bob g
 
....only 170K? If my -2 went that fast I would get a nose bleed. It is barely faster than the 180hp Mooney I had before. Mine flew half a ball out so I adjusted the springs on the rudder cables (nuts go through the firewall on each side which helped a little. I shimmed my Elephant ears with large area washers on the bolts that attach them to the horizontal to trim it to the right. It flys better but I don't know if that is a safe solution You could make a new one out of aircraft plywood. I have one off a 14-13-2 that has been turned into a clock you can have (but has an extra hole).
 
Bob... a few planes have been modified to use the "end plates" as giant trim tabs so this might be an option for you. Remember the main vertical tail is already offset to help with the trim issue. Definitely you don't want to continue to use the plates in a warped condition - that will just create more drag.

Now let's discuss the airspeed issue... if your plane is reaching 170 mph at 75% power that would be amazingly good, but 170kts is not likely except in a dive. Tell us more...
 
sometimes i may be prone to slight exaggeration. occasionally. sometimes. not often, well not very often. maybe pretty often. ok, always.

actually, it's cruise speed is about like every other cruisemaster.

sometime soon i will get around to fixing it. i think it can be done with minimal fabric work. i'll just do a little cutting and gluing.

thanks for all the input.

bobg
 
Bob,
Scott thomas mounted his elephant ears with varying stacks of washers until he no longer needed the rudder trim tab deflected on his 14-13.
I don't see any reason why you couldn't do this on the -2, but you would need to re-index the rudder spring tension to even, the rudder trim tab to even, and somehow get the flaps indexed even before you went test flying. Otherwise you may have multiple adjustments counteracting eachother and just adding to drag.
-Adam
 
i wasn't even aware that there was a spring adjusted rudder trim. you learn something new every day i guess. i never saw it mentioned.

anyway, after thinking the whole situation over the past few days, i think i know what i want to do this winter. you know i really think the roundrels are too big on the cruisemaster. i like the smaller ones on the cruisair better. they seem more proportional to the airplane. i have a friend with a cruisair, and when he gets back from the sandbox i'm going to get him to trace one as a pattern, and make me a matching set out of a fiberglass layup. that way they can never warp or bend again. i don't think the weight difference will matter, since i'm already carrying around a 7 pound weight bolted to the battery box, even though the new ones should be lighter.

but if anybody has some straight cruisair roundrels they want to sell cheap, i'm open to suggestions.

i thought of making some with an aluminum frame and covering them with fabric, but i think they would be too fragile.

got too much on my plate right now, lots of airplanes to work on and starting on a rv14 project next week with a friend. gonna be busy this fall. building a new hangar too.

btw, on the hangar thing, if any of you are considering it, i'm going with a company in bolling green kentucky, dandi building systems, who use laminated wood trusses instead of an ordinary steel building. the inside looks like a church, it's so pretty. cheaper too. and, as we all know, wood is good.

bobg
 
I'm not sure that reducing the size of the auxiliary vertical stabilizers is a good idea, or legal for the airplane.
-Adam
 
Bob, I think Adam has a good point... he's a smart kid and someday he might be president.
 
It would be unfortunate to find out that the stall/spin characteristics with the smaller tail fins were not what you expected them to be. They may have gotten bigger on the 14-19 for a good reason. :shock:
 
" you know i really think the roundrels are too big on the cruisemaster. i like the smaller ones on the cruisair better. they seem more proportional to the airplane."
I just noticed a picture of Cruisair 14-13, N86771 in the recent issue of B-C Contact Vol 29 Number 4 pg 26. The elephant ears are missing, and the vertical stab/rudder look taller.
I looked up the N registration, this ship appears to be normal category (not experimental). I would love to look at the 337 forms for the various mods.
 
Do not change the size of the aux fins...period. Use the old ones as a pattern to make exactly the same size. Use Finnish birch. It has more plies and is stiffer.
Scott, Don't believe everything you read on the registry web site. I catch errors all the time. If this airplane isn't "experimental," I'll bet it is a bandit.
 
I might know some guy that few his -3 with one ear removed (had a ferry permit) and it had no discernible effect for the 50 mile flight.. so, he took off the other one too and tried it. a little less yaw stability but not as bad as a v-tail bonana.
Of course, he didn't try any spins...

I once saw a -2 at a little airport in Oklahoma that they guy put ears on it actually shaped like elephant ears.. it was ugly.. looked like it had a mid-air exchange with Dumbo.. gas island locals said it had been that way for for quite a while.

the previous owner of my -3 reversed the ears-- I didnt notice for several months. When I wrote him about it he said he thought it looked better (it didn't)
 
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