Kay C Caldwell
  • Gunnison, UT
  • United States
Share on Facebook

Kay C Caldwell's Friends

  • Scott Raynal
  • Ant Hudacek

Kay C Caldwell's Page

Profile Information

Aircraft Model
Project Status
Nearly done
Building From
Engine installed (or plan to install)
Building Experience
Have worked on airplanes before
Flying Experience
Private Pilot
Home Airport (ie. KMYJ)

Kay C Caldwell's Photos

  • Add Photos
  • View All

Kay C Caldwell's Videos

  • Add Videos
  • View All

Kay C Caldwell's Blog


Posted on May 7, 2018 at 2:57pm 1 Comment

Hey just want to throw this out there, my daughter is the one that did my first flight video from crappy go pro and other clips my buddy filmed.  If any of you would like a video of your projects edited,put to music etc,etc she said she would do it for cheap.  She is a struglging college freshman looking for extra tuition money....Thanks Kay C. Caldwell..

tail dragger

Posted on August 2, 2017 at 6:41pm 2 Comments

Wondering if anyone else thinks Zenith should design an all new STOL that is a tail dragger???  Love the performance but I wish they had a tail dragger version.  Don't much like the looks of the conversions I've seen.....Just a thought..

Kay C

Comment Wall (15 comments)

You need to be a member of Zenith Aircraft Builders and Flyers to add comments!

Join Zenith Aircraft Builders and Flyers

At 1:22pm on October 18, 2017, Michael T. said…

This post was long so I had to break it up.

I was looking over this "Complete CH 640 Errata"

Did you find any problems in the plans worth noting?...like lightening holes in the wrong place..etc?

I was looking this list over and maybe its all been fixed over time, Just wanted to check with you before I start cutting and bending...lol

Maybe this list below is outdated

At 1:18pm on October 18, 2017, Michael T. said…

Fuselage Discrepancies

  • Drawing 640F2, Revision 7 - Item 0, H.T. Frame Assembly.
    • An overall reference vertical dimension of 500 mm should be shown on this assembly and the top (L) rivets should be called out to be installed on assembly. The back of the 640F3-1 Rear Side Skin is 500 mm tall. The H.T. Frame needs this same height when installed. The 495 mm height of 640F2-4 implies an assembly height of 495 mm.
  • Drawing 640F4, Revision 17 - Vertical position of the 640F4-3 should be 143 mm from the top of the upper longeron to the center line of the 60F4-3. This is calculated from the positions of the 640-F27 H.T. Tail stops and the required deflections shown on 640M50. This dimension was confirmed by the factory on 21 Sep 2009.
  • Drawing 640F14, Revision 12 - The assembly drawing in the upper-left shows a callout to part 640F24-2. This part does not exist and should not be shown on this drawing. The older hand-drawn drawings do not show this callout or part drawing.
  • Drawing 640F18, Revision 7 - Engine Mounts.
    • Item 1, Lower Engine Mount - End plate overall length should be shown as dl=52, not 44 mm.
    • Item 3, Upper Engin Mount - To achieve the 17 degree angle, the dimension for the angle on the body should be changed from 7 x 35 mm to 11 x 35 mm. The end plate overall length should be shown as dl=56, not 44 mm.
  • Drawing 640F19, Revision 8 - In the upper-left corner, the length of the crossbar is shown as "l=306 +1/-0". This should be "l=301 +1/-0" to end up with the dimension shown on the bottom as [300 +1/-0].
  • Drawing 640F22, Revision 15 - The fuselage assembly dimensions show "(430)" from the firewall to the instrument panel. This should be "(480)" to match the other dimensions and the length of the 640F14-1.
  • Drawing 640F24, Revision 11 - The upper-right corner shows a dimension of "[360]" between the firewall and the 640F24-6. This should be "[410]" from 640F14 assembly detail.
  • Drawing 640F26, Revision 7 - Item 5, Lower Rear Side Skin Stiffener. Experience shows the top width dimension of 142 mm should be 150 mm. This leaves 11 mm, instead of 15 mm, for the width which is cut. The bottom 172 mm width should be 176 mm.
At 1:17pm on October 18, 2017, Michael T. said…

I was looking over this "Complete CH 640 Errata"

Did you find any problems in the plans worth noting?...like lightening holes in the wrong place..etc?

I was looking this list over and maybe its all been fixed over time, Just wanted to check with you before I start cutting and bending...lol

Maybe this list below is outdated

Wing Discrepancies

  • Drawing 640V1, Revision 4 - Item 1, Wing Spar Extension. The plans dimension "~405" to the first lightening hole. Change this to 350 mm.
640V2 wing spar extension assembly shows the lightening hole half-way between the two (L) pieces.
Adding the dimensions: 25 mm for spar cap overlap + 225 mm from overlap bend to first (L) + 100 mm from first (L) to center of lightening hole = 350 mm.
  • Drawing 640V1, Revision 4 - Item 4, Upper Rear Spar Cap. Minor typo on plans. Length should be 3390 mm, not 3391 mm. Lower spar caps should be 21 mm longer than upper spar caps. See 640V6 spar root detail.
  • Drawing 640V4, Revision 10 - Item 4, Rear Spar Upright. The top "dl=87" dimension should be to the left phantom line, not to the left corner of the cut piece.
  • Drawing 640V5, Revision 12 - Center Web and Spar Cap Assembly.
    • Upper assembly drawing has a callout for 640V3-1, yet points to the 640V3-5. Change this callout text to "640V3-5".
    • The lower assembly drawing shows an (L) callout for the short angles riveted to the 640V3-5. An (L) is defined using 0.025 material, yet these angles should be 0.032 thick 640F40-12 material. See 640F41 Rear Floor Support + Tunnel Installation detail.
    • The lower assembly drawing shows a callout for the "rear spar upright 640V4-3". The part number should be 640V4-4.
  • Drawing 640V6, Revision 8 - Wing Spar Assembly.
    • The top-right corner of the drawing shows a dimension of 102 mm from corner of the web to the first rivet hole. This should be 118 mm. See the Spar Root Detail dimension stack-up: 40+30+30+18.
    • A similar error just below the last one. The 103 mm dimension from the bottom corner of the web to the AN5 bolt hole should be 120 mm. See the Spar Root Detail dimension stack-up: 35+30+30+22 to end of cap + 3 to corner of web.

Tail Discrepancies

  • Drawing 640T7, Revision 3 - Items 1 and 2 Rear Skin and Nose Skin. The drawing shows a 2 mm dimension between the ~1277 horizontal dimension on Item 1 and the horizontal dimension of item 2. This implies that the item 2 dimension should be 1275 mm. The item 2 dimension should be 1315 mm, symetrical to the bottom of this piece. The 2 mm dimension should be to a phantom 1317 mm dimension on item 1 before the corner notch is cut.

At 11:52am on October 18, 2017, Michael T. said…

Hi. I was wondering if you would be open to loaning out your CH640 form blocks and any other jigs. for a month to 60 days, I cover all costs. Treat them well and return them not to badly beat up...lol

At 10:38am on October 16, 2017, Michael T. said…

At 10:22am on October 16, 2017, Michael T. said…

I was watching some of the Ch640 videos online on Youtube.. CH-640 presentation (Part 1)

I think its a Video made by Jeff Paden. In that Video he relates that the Alarus originally had a large rudder, in 2003 the Alarus went to a smaller rudder but the CH640 retained the older Alarus large rudder.

Jeff also posted a materials list in the video and parts sheet cut out. Would be great to find those for current or future builders. Do you guys have any contact info for Jeff, does he post here anymore?. Iver tried to email him from the address listed in his old build website but it just bounces back

At 5:35pm on October 15, 2017, Michael T. said…
The 640 plans make reference to large rudder on some drawings but just rudder on others. Is that a hold over from the ch2000 alerus having a smaller rudder? And they made the ch640 bigger
At 6:54am on October 14, 2017, Michael T. said…
Did you make your own counter weights, any suggestions there if you did, or did you buy some parts from zenith.
At 9:14am on October 13, 2017, Michael T. said…
I was looking over the ch640 plans ...the term dl or developed length, is that just the pre bent size of the parts before bending?

I was going to play around with scrap to get a good idea of what the bending process does to the size of the parts.
At 6:17pm on October 11, 2017, Michael T. said…

Small world, years ago I called Don Parnam from an ad in the back of kitplanes magazine. I was considering putting an auto conversion on my RV-7 kit I was building.

He talked to me at length and answered all my questions. I wondered why he had no web page and he said he was old and didn't have the know how.  I never ended up buying anything from him but he educated me for free....so

As a thanks I whipped up a Geo-cities web page for him with google photos of his installs. You might have seen his site.  but that site would have gone down with Geo-cities closing.

I never knew what happened to Don, is he still around?


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, power distribution panel, Approach Fast Stack harnesses, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2020   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service