Vibrating Turtle Deck

[AMK53]

I finally put my entire Kitfox together including the turtle deck after a year of work on it. When running the engine, the turtle deck seems to vibrate a lot. Is this common for Kitfox aircraft? Is there a way to avoid this? There's not a lot of room between the turtle deck and the windshield to add any rubber or foam, so not sure how to deal with this.

[jrevens]

The all plastic turtle deck cover is pretty flexible, and even if you are not going to cut and hinge it, it would help to install a stiffener in the middle going from one side corner to the other side corner, made of a length of aluminum angle or something similar.

[jiott]

I also was bothered by vibrations at idle and during taxi-seemed fine in flight. I put some teflon anti-chafe tape on the upper edge where the turtledeck slides into the windscreen slot to tighten it up some. It did help quite a bit but not completely. I may try what John suggests to stiffen it up.
Actually it does not bother me a whole lot since it is only noticeable at idle; been living with it for 950 hours.

[airlina]

Luckily years ago when I was building , I found out that this was a common complaint from builders who had already finished their airplanes. Turns out that LP Aeroplastics makes a domed turtle deck that I went with to eliminate this. The only time I get the Vibes is in a full slip which is OK because it makes me pay attention. Bruce N199CL

[AMK53]

I also was bothered by vibrations at idle and during taxi-seemed fine in flight. I put some teflon anti-chafe tape on the upper edge where the turtledeck slides into the windscreen slot to tighten it up some. It did help quite a bit but not completely. I may try what John suggests to stiffen it up.
Actually it does not bother me a whole lot since it is only noticeable at idle; been living with it for 950 hours.

my main concern is for it to not break during flight. The vibration doesn’t seem to be isolated to idle though. As I power up on ground, it increases further.

[Dave S]

AMK,

One little trick I did on our kitfox was to use a strip of plastic V seal on the upper forward edge of the turtledeck - mostly to assure closure of an unnecessary "Pneumonia hole" for winter flying; but, also to have something that could take up the space for a better fit. The V seal does quite well at that. Never had any vibration or chattering problems with the turtledeck.

Not sure if all of our aircraft would work out the same - ours has a Rotax and the aluminum framed polycarbonate glazing. If I recall, you have a radial engine and may have the acrylic one piece turtledeck - might react a bit differently - don't know.

What I can say is if you do have the aluminum framed turtledeck with polycarbonate glazing - it won't break. Acrylic one piece - don't know. You can beat polycarbonate with a hammer and only scratch it - won't shatter.

[jiott]

The one-piece turtledeck is polycarbonate; it will never break.

[AMK53]

I think due to my very large prop, the prop wash just has a larger impact on the turtle deck on ground (have yet to fly it). I purchased on the turtle deck hinge to install, so I think I will add a very small 90 angle behind the hinge to stop any of the vibration.

[aviator79]

I finally put my entire Kitfox together including the turtle deck after a year of work on it. When running the engine, the turtle deck seems to vibrate a lot. Is this common for Kitfox aircraft? Is there a way to avoid this? There's not a lot of room between the turtle deck and the windshield to add any rubber or foam, so not sure how to deal with this.

How well it's your prop balanced? My turtle deck used to vibrate like hell at about 2500 RPM. I did a better balance job, and it is much more subdued now. I do have a hinge and Al stiffener.

[n85ae]

I have a Series 5 with the one piece Turtledeck, and the flimsy aluminum frame. As designed/installed
per the plans ... it was annoying since the aluminum housing, with the big piece of polycarbonate is basically
oil canning in flight, and taxiing all the time.

I put a piece of angle aluminum across the mid point of the turtledeck/window fastened to the window with
Truss Head screws, and nuts. The angle stiffens the center section of the window/turtledeck and provides
a connection point for a V brace to the airframe.

There is an inverted 'V' brace (3/8 6061 Tubing, with flattened ends) that I made that connects to the
cross member which the seat belts are attached to with Adel clamps. The V brace then connects to the
Angle/Window with a Camloc.

I had not only a dislike for the ever present rattle when taxiing on turf, or buffeting in slow flight, and
a constant nagging worry about it blowing out when the doors were off in flight.

I don't look out the back in flight, so it doesn't bother me to have the extra structure there, and it
impedes nothing in the baggage area ... So to my thinking a good upgrade.

I'll post a pic next time I get out the airport.,

Jeff