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Rigging - it’s worth a look


GLJA

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Had a J owner friend volunteer to help with the rigging of my 74F. Prior to checking it out, I was getting no more that 130 KTS IAS on the speedometer. 
I flew up to his heated hangar today (we are in Canada. Heat is important in February) and using his travel boards, did the following:

- set both ailerons to 0 degrees (one was +2, other was -.5)

- set flaps to -1 degrees (from 2 degrees on one to 0 on the other)

- rotated the exhaust towards the rear (it was almost pointing straight down)

- rotated the Lasar tie down rings 90 degrees (I had them pointed to the back)

- adjusted the trailing edge on the rudder (I was requiring to use left rudder to keep the ball cantered. The trailing edge was bent to the pilot side substantially)

- adjusted the cabin door so the leading edge sealed better to the fuselage (there’s was a 1/8” step between the door and the fuselage .

Total time, including the BS sessions and checking out his panel improvements was around 2.5 hours  

We took our planes for a rest flight after. The result was a 138 KTS Indicated airspeed! TAS resulted in 147 KTS, which is right in line with the POH expectations.

My aircraft hasn’t been washed or waxed in months, so I’m looking forward to giving her a bath once the weather warms up to see if I can’t break the 150 TAS mark.

It’s worth taking at look at your rigging for an easy speed pick up. 

 

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36 minutes ago, N201MKTurbo said:

Did you check the gear doors? There is sometimes a knot or two there.

We did. He didn’t have Jacks

available, so I did a low and over when I flew up there. Then he flew under my plane when we test flew after. Said they looked good

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Just now, RLCarter said:

There are numerous threads on here about making travel boards, I’ve been looking for a set to buy or copy for years

I do know that the guy made copies of these before and sold them. I could see if he has the CAD 

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Glad you found some extra speed. But beware-

From what I have seen, many of these vintage planes have plenty of worn pieces in the system and plenty of them have had the control linkages meddled with more than once over the years....

A complete (proper) rigging will also include:

1.  setting the position of the aileron center links pivot below the floor; checking the aileron/rudder interconnect spring setup.

2. setting each aileron bell crank to its neutral position

3. adjusting the aileron up and down throws (bell crank stops)

4. adjusting the flap stops and checking degrees of each flap at max extension

5. setting rudder to neutral position and adjusting rudder throw (stops) in both directions

6. checking elevators are equal and checking the throws (stops)

If you are just using the boards to set aileron positions without checking the positions of the bell cranks, you are most likely changing the amount of control travel you have (reducing one aileron travel and possibly increasing the other). In my limited experience, if the aileron bell crank stops are not set properly after [edit] adjusting the centered aileron trailing positions, you’ll end up with uneven aileron throws. The TCDS and the service manual have everything you need if you have travel boards in hand- be sure to follow the process form beginning to end (It’ll take all day). I’ve done 6 planes so far, and have yet to encounter even one where anything was even close to spec. You can set it up to fly straight, but you might not be contacting the bell crank stops on each side in each direction, and may not have enough control throw. 

 

 

 

 

Edited by PilotCoyote
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