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Permalink Reply by Michael radtke on Tuesday

Hi steve,  thats a good looking 701 you have.  As for the bubble doors (701), i purchased a set from zenith , about $2k w shipping.

Just be aware that they are the fiberglass frame edition, not the new alum sq tube edition like the 750 series.

the fiberglass doors come basically finished , all you need to do is add the door latch hardware which comes with the door kit.

the fiberglass frames 701/750 have the latching handle up front and many builders added a rod going rearward to secure the aft end of door. the bubbles create lots of suction which bowed out the rear and cracking of fiberglass and/ or plexi.

the new sq. alum frames for 750 has latching handle in the middle of lower frame.

im not sure if zenith will come out with a sq alum frame for the 701.  

you should be able to use the already riveted top half of hinge in your existing 701 upper door frame. just match up the lower new hinge on fiberglass frame.

i hope this answers your questions., if not please ask away!

cheers,

michael.

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Permalink Reply by John Austin 4 hours ago

the fiberglass frames 701/750 have the latching handle up front and many builders added a rod going rearward to secure the aft end of door. the bubbles create lots of suction which bowed out the rear and cracking of fiberglass and/ or plexi.

On my 750 STOL (Edition 1) with fiberglass door frames, the latching handle is at the front lower corner of the door as you describe, but midways back there was a pivot with a latching rod that went aft to secure the door at the aft lower corner - this was the standard design and not a builder's mod.  However, you are correct that the bubble creates a lot of lift or suction that tries to pull the lower part of the door out.  If the front latch doesn't sufficiently overlay the framed opening, it can allow the door to slip open.  Two things were critical to preventing this - having sufficient latch overlap and many builders (including me!) added a secondary latch approximately mid-way up the leading edge of the door frame to prevent it from bowing open.

Simple latch on leading edge of door to prevent bowing-out:

Bottom edge door frame showing pivot with rod (actually, I replaced the forward rod with a tube that was more rigid - the original steel rod was prone to flexing) going aft that secures door at back lower corner.  I modified the pivot, extending it so as to make a secondary handle (Walt Snyder's idea!) that is much more ergonomically useful than the forward handle - either one will open the door - (they are red for obvious reasons!):

Zero issues with this set-up for 900+ hrs and 13+ years, so I never bothered to upgrade to the square tube door frames.

John

N750A

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Permalink Reply by Michael radtke 4 hours ago

Hi John,

      Thanks much as always for your posts, yea i didnt know rear rod was standard. this came with 750 door kit?
this is not std on 701 doors, i made my own mod. also good idea. for front latch  where did you get that handle/ latch? i’ll look on amazon for something.

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Permalink Reply by John Austin 4 hours ago

Yes, the rear rod and pivot was standard included with the doors.  The front latch is the standard handle to which I riveted the red grip to improve the ergonomics of grasping the handle.  (Forgot to mention that above!)  The secondary black plastic latch is a marine hatch latch - think I got it from West Marine.

John

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Permalink Reply by Steve Sickle yesterday

Thanks for that info. I think I'll stay with the stock doors, they work fine......Steve

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