Author Topic: Need everything  (Read 4999 times)

Culver Dreamer

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Need everything
« on: December 30, 2011, 11:09:36 AM »
  Hello Guys: I can't find a project Culver Cadet, if you know of one please send me an e-mail at pennair@hotmail.com. Since I couldn't find a project I bought Neil La France's STF plans and intend to go ahead with it. If you have any parts particularly metal ones it would help speed up the build time for me.  Here is a question for some of the more knowledgeable in the group. I see some pictures of cadets that have a strut from the bottom of the fuselage to the horizontal stab. Not all have this what is the reason for this? If there is a weakness back there then why not have flying wires from the fuselage to the horizontal stab and continue up to the vertical stab like the Piper Cub for example.
 Mark

Bill Poynter

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Re: Need everything
« Reply #1 on: December 30, 2011, 01:13:56 PM »
Hi Mark,  I've seen Cadets with the struts that you mention.  I've obtained the FAA airworthiness records for a couple of them to see what I could learn.  So far, I've found no 337 forms on file documenting this strut installation. 
My guess on the question of struts verses flying wires is that the Cadet horizontal stab is one piece with a heavy spar from tip to tip.  The Cub horizontal stabs are two pieces and were designed to be supported by the wires.
There was a service bullitin concerning the Cadet longerons becoming crushed from overtightening the stab attachment bolts.  I believe that the stab attachment is adequate if the longerons are undamaged.  This would be a non-issue on the metal fuselage STF plane.

Paul Rule

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Re: Need everything
« Reply #2 on: January 04, 2012, 04:37:14 PM »
The stab attach bolts could be over tightened on the wood stringer and crush the wood thus causing a loose stab.  The struts are a not approved, home-brew fix.  There is an approved repair to replace (splice) the wood stringers to get back to good wood.

The Helton Lark had a reinforced tail attach but the wood could still be crushed with over-tight bolts.
Culver Service Memorandum #12 (5-28-42)  addresses the issue so it was known early on.
« Last Edit: January 21, 2012, 04:52:47 PM by Paul Rule »

Paul Rule

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Re: Need everything
« Reply #3 on: January 04, 2012, 04:38:32 PM »
See my post in "Culver parts"

Bill Poynter

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Re: Need everything
« Reply #4 on: January 21, 2012, 03:14:03 PM »
Paul,  How does the Lark stab attachment actually differ from the Cadet?  Is that a mod that could be applied to the Cadet?

Paul Rule

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Re: Need everything
« Reply #5 on: January 21, 2012, 05:09:55 PM »
Lark put a solid block of spruce between the two top longerons in the last (tail end) bay.  They then plated it top and bottom with 3/32" plywood.  It has some fancy cutouts front amd back to clear the elevator pushrods but that's about it.

The 3/16" block of hardwood plywood under the forward bolt hole is glued on last as per the #12 Memorandum.  I think there are planes still out there that never had that done correctly ( and maybe got the struts put on as a stopgap).

I have done it to one airplane and I think Carl Badget did it to 3 or 4 that he did.  It really spreads the loading out well and makes the stab really stiff even out at the tip.  The other thing to do is put larg area washers (AN970-4) between the fuselage and stab on all 4 attach bolts.  They give a little more area then the steel fittings alone.  Of course, all 4 holes in the longerons should have thin wall steel bushings (5/16" od x 1/4" id) in them to prevent crushing.

Neal LaFrance

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Re: Need everything
« Reply #6 on: February 08, 2012, 12:41:15 PM »
Mark, Look at the picture posting of the Cadet STF airplane on the web might give you some ideas.

Culver Dreamer

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Re: Need everything
« Reply #7 on: February 08, 2012, 12:58:42 PM »
  Thanks Neil:  I've been studying every picture I can find online of your Cadet STF. I'm really looking forward to seeing it in person!  Mark

Bill Poynter

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Re: Need everything
« Reply #8 on: February 15, 2012, 09:28:15 AM »
  Hello Guys: I can't find a project Culver Cadet, if you know of one please send me an e-mail at pennair@hotmail.com. Since I couldn't find a project I bought Neil La France's STF plans and intend to go ahead with it. If you have any parts particularly metal ones it would help speed up the build time for me.  Here is a question for some of the more knowledgeable in the group. I see some pictures of cadets that have a strut from the bottom of the fuselage to the horizontal stab. Not all have this what is the reason for this? If there is a weakness back there then why not have flying wires from the fuselage to the horizontal stab and continue up to the vertical stab like the Piper Cub for example.
 Mark
Here's a photo of a PQ-14 with struts on the horizontal stab.  I wonder if this was a field mod or if it came from the factory that way.

Culver Dreamer

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Re: Need everything
« Reply #9 on: February 15, 2012, 02:13:30 PM »
Hay Bill thanks for the picture. I had to laugh when I saw the pitot tube. Who designed it like that. I wonder how often on walk arounds they hurt some poor pilot and got bent in the process. Also what are the two forward facing tubes around the top of thefirewall?
  Mark

Brett Lovett

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Re: Need everything
« Reply #10 on: February 15, 2012, 10:05:42 PM »
Very interesting.  I've never seen a PQ-14 with struts before.  I also wonder what the significance of the tail number is "PI-X30".

Bill Poynter

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Re: Need everything
« Reply #11 on: February 15, 2012, 11:59:45 PM »
I think the photo was taken in the Philippines.  That may have something to do with it.