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Messages - Paul Rule

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Maintenance and Repair / Re: Part # for Marvel Schebler MA3 / Ma3A?
« on: July 16, 2013, 01:27:19 PM »
I have 6 pages of "Operating & Maintenance Instructions for the MA-3A  p/n A10-2302 as part of my 4AC-199 Maintenance & parts book.

The 6 pages include an illustrated parts breakdown... but no data plate..  For me the answer is - no data plate on these early carbs...  the p/n should be stanped into it probably on the lower flange where the air box bolts on.

This is all in the Franklin manual that Bill P. copied elswhere on this site.

Maintenance and Repair / Re: Elevator push rod support tube
« on: July 16, 2013, 01:17:32 PM »
I also thought phenolic to begin with but mine  has no fabric in it.

I think it was a form of bakalite or melmane.   Not sure about that yet.


Maintenance and Repair / Re: Elevator stop
« on: July 16, 2013, 01:11:05 PM »
From an OLD (1973)  Culver news letter the following control surface rigging info:

     Ailerons         UP  17   (+- 1)     DN   15  (+- 1)
     Rudder          R    34   (+- 1)     L     31   (+- 1)
     Elevator         UP   21   (+- 1)    DN   30  (+- 2)
     Trim Tab        UP    19.5            DN   19.5

Aileron stops should be clear of aileron hinge bracket attach bolts.

The PQ8 Military maintenance manual stated: 

     Ailerons         UP  15   (+- 1)          DN   14  (+- 1)
     Rudder          R    37   (+- 1)           L     34   (+- 1)
     Elevator         UP   12.5   (+- 1/4)    DN   30.5  (+- 2)
     Trim Tab        UP    12    (+- 2)        DN   11(+- 2)

Although the PQ8 was the same basic airframe,  the demands (or limits) of early technology radio control may have dictated some of the differences.

P. R.

Maintenance and Repair / Re: Elevator stop
« on: July 13, 2013, 07:29:18 PM »
hello Stefan,

The elevator should have an "UP" stop on the tube where it goes past the two main spars under the seat.

It is a simple tube clamp with a small steel triangle welded to it that hits the spar face at the right angle.

I thought we had posted rigging angles somewhere but will do it again in a later post here.

The PQ8 erection manual (posted elswhere) has control surface rigging angles (that may or may not be the same as the civilian Cadet.

Paul R.

Thaea were 133 Cadets on the FAA registry (as of 2/ 2012).

My guess is that there are maybe 60 to 75 that are airworthy.


Culver General Discussion / Re: New wings for the Culver Cadet
« on: July 13, 2013, 07:17:54 PM »
Here (FINALLY) are those ANC-18 pages on the wing spar tests from long-long ago.

Paul R.

Culver General Discussion / Re: Albert Hook and his Culver Cadet
« on: November 20, 2012, 08:30:48 PM »

This clip was VERY interesting to me....   Al Hook has owned his Culver for many years ( maybe over 55 yrs!).   He was an engineer for Howard Hughes for many years and used his Culver to commute to work in the LA area!

The Culver sat outside at Torrance Airport for several years before I went there and helped him disassemble it and pack it in a U-haul truck.  He took it up to Carl Badgett in WA state who completely rebuilt it.  Al and I then (after local test flight) spent two beautiful days flying it back down to Torrance (2006 if I recall).  Some of the clip was our return to Torrance. 

Al has had some serious health issues recently and the Culver is for sale (or already sold by now).  The clip is a very well done collage; done (I think) by a son in law for the fun of it....and to encourage AL.   

Sorry, I feel sure there is no full length feature to follow.


Culver General Discussion / Re: Franklin engine and prop
« on: November 07, 2012, 10:34:16 AM »

I don't think you can (by looking through the TDS) find a (certified) Franklin 90 turning a metal prop.  Although the Franklin book does not specifically prohibit metal there have been (old) reports of crank failure with metal props.  The Franklin crankshaft, I have been told, has a larger inside bore then small Continentals.  I have not personally confirmed this. 

Wood absorbes power pulses better then metal.

My recomendation... use a wood prop and check that it gives aprox. same static RPM as a certified installation of similar performance.  Then in-flight it should not over speed the engine unless you are near max level flight speed or in a shallow dive.

Culver General Discussion / Re: spar tip repair
« on: November 07, 2012, 10:17:41 AM »

Use the Culver "General Repair Instructions" from the parts book.  These instructions can be considered approved data.

Par. #5 says: "... if the (damage requires) greater then aproximately 20-24 inches it is advisable to replace a section of the spar cap..."  This clearly allows a scarf repair of a cap section anywhere on the spar.

Although this paragraph is addressing inboard damage it is conservative to apply it to outboard sections as the loading decreases as you go outboard.   The essential thing (in my opinion) is that you do a 20:1 scarf as specified. 

The spar repairs in 43.13 allow a 10:1  scarf with reinforcing plates because the (CAA at that time) believed that a 20:1 was too difficult for the average mechanic to do in the field.  The Culver repair data pre-dates the 43.13. 

Both Piper and Aeronca were approved to make 20:1 scarf splices ANYWHERE in their wood spars and did so on a routine basis.  Aeronca also glued smaller boards together both horizinally and vertically the length of the spar (effectively a laminated spar) to build up spars.  I have seen several of these and recently replaced an Aeronca Chief spar that was made up of 7 pieces of wood.

From this it would appear  20:1 scarf without reinforcing apparently generates 100% (or more?) of the required strength.

Culver General Discussion / Re: New wings for the Culver Cadet
« on: September 13, 2012, 10:42:23 PM »
I am not sure if this has been said before or not but there are no differences between the 'light' and 'heavy' spars outboard of the gear attach.  I do not know when the change was made or even if it was a consistant change.  I have a bare Helton spar and it is a 'heavy'.  I have several others but don't recall what they are.  The only advantage I can see is that the 'heavy' spar won't split in the filler wood between the two big attach bushings.   It is a good practice to push out those bushings every time the wing is off to inspect the inside bore for cracks.   On the other side of the coin, those cracks are not in the spar caps... just in the filler blocks in between the caps and probably indicate humidity expansion and contraction more then any over load or stress causes.

The helton spar I have has vertical grain plywood blocks all along the spar at each rib attach point.  I know the Culver Corp spars all had solid spruce vertical grain blocks at the same points but the large blocking was all horizonal grain.

It is possible the 'heavy' was a Helton thing or maybe a PQ-8 thing and over the years we have gotten them mixed together. 

Dan is that 'light' the spar I traded to you?

Culver General Discussion / Re: New wings for the Culver Cadet
« on: June 28, 2012, 12:11:23 AM »
I will get a scan of those pages but not until probably mid July. 

The hollow spar is true.  I do not know when the change occured but I have both kinds of spars.  The hollow was between the outboard fuselage attach and the inboard gear attach.  The hollow was front and back of the center 45% shear ply and the transition to solid blocking was cut on a double curve.  There were also vertical blocks at all rib attach points. 

I doubt that there is any important strength difference between solid & hollow because the failures of the test spars were eithere at the inboard attach bolt or at the landing gear bushings as far as I know.

Modifications / Re: Franklin vs Continental
« on: May 20, 2012, 11:18:32 PM »
I did not use auto fuel because it's not approved for the Cadet and because of the alcohol content.  Non- USA gasoline w/o the alcohol might be worth looking into.  As for oul - here in the (warm) AZ desert I just used Shell W-100 which worked fine and did not spike the perssure at all.   

Modifications / Re: Wing Root Fairing
« on: May 08, 2012, 04:51:34 AM »
Some of my aero design books talk about wing root fairings and when to use them...   Looking that over, it seems that they are most benifical when the fuselage has a marked taper in the wing root area or because the fuselage is rounded, there is quite a bit less then a 90 degree angle between the fuselage and wing.  The Cadet is more or less a straight and square fuselage betwee the FWD and AFT spar attach points and begins to taper rather slowly after that so the value would be much then some other shaped fuselages.  Mooney was thinking speed all the way...  got to think he considered that, or that he built the fuselage as he did to reduce the need for fairings. 

Modifications / Re: Lycoming O-235
« on: May 08, 2012, 04:38:05 AM »
Far as I know only one Lycoming was put in a Culver in So. Cal somewhere back about 25 years ago.  I think there was a bad result (accident) but have no idea if it was engine related.

Modifications / Re: Franklin vs Continental
« on: May 08, 2012, 04:35:45 AM »
Franklin aka: Air Cooled Motors  (back in 1942-43) recomended top o-haul at 250 hrs and major at 500 hrs.   That said, keep in mind that such tools as differential compression testers did not yet exist (or were just begining to be used by a few)  and the gasoline and oil quality was only a ghost of what it is today :).

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