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Messages - Paul Rule

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76
Modifications / Re: Need everything
« 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.

77
Culver General Discussion / Re: Franklin 90hp Engine?
« on: January 04, 2012, 04:31:13 PM »
Franklin 90 is a good engine... just won't last as long as a Continental.  Nothing wrong with that,  it will give you plenty of warning as the rings and valves seem to be the first to go.  Just do regular compression checks. 

I have a Franklin 85hp (which is just the 75HP spun faster) that has 1300 hrs on it and has been topped 3 times without spliting the bottom end. 

Also, wood props ONLY!  Metal props are not approved on the 90hp for sure (but also on the 75 /85 I think).  The crank is lighter and will eventually break.

78
Parts Wanted / Re: LCA engine mounts
« on: January 04, 2012, 04:22:43 PM »
Think I have one... see "Culver Parts"

79
Culver General Discussion / Re: For you Culver guys
« on: January 04, 2012, 04:15:27 PM »
I have flown the Sensenich  -54 prop on a Franklin 90 and found it a little high reving, more like a climb prop.  I think I remember that -54 inches is the maximum pitch for that TC.  Talked with one of the old prop guys Sensenich who told me that there is a manufacturing "plus/minus" on pitch and that if requested, he could make one to the high limit which would be closer to a mid range pitch.

Just a personal observation...  such a clean airframe and wide speed envelope... I have seen 3 different props on the Franklin 90 that would all overspeed in level flight even up at 9500'.  I am not sure there is any (fixed pitch) prop that would not do so.  I do know that years ago 1 (or more) Cadet, probably with 75hp, flew off the end of the runway in ground effect.  I expect it had a high pitch prop and may not have made the minimum static RPM on the ground run.

80
Culver General Discussion / Re: Mechanical landing gear
« on: January 04, 2012, 03:55:24 PM »
Hello all, 
I'll add my two cents to the dashpot...   Even if one is installed and in perfect working order it would be DANGEROUS to release the gear and let it fall trusting the dashpot to lower it slowly.  I have never seen one I would trust.  If it does not snub the fall something is almost sure to let go like the down stop or the push-pull pivot bolt or the "half moon" plate attach bolts.  Next??  An unhappy landing because you have a slim to none chance of getting the lock pins in place.  ALWAYS hold the wheel and let it slide slowly down!!

Why?  The dashpot has no o-ring on the piston, just a close fit in the cylinder so it's not very efficient and a little scoring or roughness on piston or cylinder and it's not likely to work well even if just serviced full of oil.  As someone said earlier most (if not all) leaked.  Just a little air in it and BANG.

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