Horz stab vibrating?

[hatz215]

Given the fact that most Hatz's are flying with single wires, I don't think there is much of a load on the front wires. They are there to dampen vibration. Certainly no distortion issues on my airplane. I just finished recovering last year and everything was good inside.

Steve

photo.JPG

[stearmoth]

Hi Steve,

Very nice Hatz by the way! I really don't think it's a problem with the vibration, but Michael's Hatz has an 180hp engine, which will yield in a few more mph!

Hans, Switzerland

[splischke]

I'm using 1/2" 4130 round tube for braces as shown in the attached pictures. Pretty much duplicated what's on the Acro Sport II plans. It's a proven and very inexpensive method to add support to the stab. If I used 4 wires with terminals from Bruntons it would cost about $700.

-Scott

[mtaylor]

I have 8 wires on my tail, top wires streamlined and round on bottom. Yes, the extra Brunton wires are an extra $700. I'd rather have gone with a streamlined tube brace off of the lower longeron up to the leading edge horizontal stab. I did the strut method on my 2nd Pitts because my first Pitts experienced a completely severed front horizontal stabilizer tube due to a crack that formed at the front stab mounting bolt hole. That Pitts had no front stab support. I think a dull bit was used to drill that bolt hole and then the hole was not deburred and chamfered. What kept the leading edge tube from sliding off of the inner H tube assembly in flight, thus causing a snap roll that wouldn't have ended till I hit the ground, was about 5/8" of tubing overlap. Again, I think the crack started due to a badly drilled bolt hole but then propagated due to vibration and stress. My preference is a tube brace over wire brace, and would do it that way if I had to do it over again. But the wires looks good in my opinion and it works to reduce/eliminate vibration.



Just my opinions based on my experience and submitted FYI...

[mtaylor]

BTW, I didn't build my first Pitts...just wanted to clarify that.

[jwhanson]

We have 170 hours on our Classic and so far have never noticed any vibration of the horizontal stabilizer. On an early flight there was a lot of vibration of one of the streamlined cabane wires. After turning the wire slightly to conform to the slipstream the vibration stopped. I would expect that a misaligned tail wire could cause some vibration to be felt.
John Hanson HC-012

[mmcgrew]

Horz stab is vibrating. I took a small hand mirror along and could see the right side vibrating in the wind. I am going to add a stramline strut on the bottom of the leading edge back to the fuselage. I think this needs to be a plan change on all future plans.

Michael
N9648B

[mmcgrew]

The Fix

Support strut.jpg