SHOULD WE RE-WORK THE S7 TO ENABLE REAR SEAT SOLO FLIGHT?

Piper Cubs are soloed from the rear; why not the S7?

 

Tandem seating aircraft can have CG issues which may suggest that soloing from the rear seat is preferable. For example, early model S7ís tend to have a more forward CG when soloing from the front seat. The pre-1995 models which have a small trim tab and unbalanced elevators can have moderately heavy stick forces when trying to land in a full stall mode. On this 94 with the battery moved forward to the baggage compartment and a 10 pound weight bolted to the lifting handle Iíll still occasionally want to pull back with both hands before touch down and it even has the longer trim tab. The CG with me (190lbs) and minimum fuel is at 44Ē aft of firewall (this is well ahead of the forward limit of 48Ē).

 

With a passenger, which moves the CG to 50 or 51Ē trim and stick pressures on landing are just fine.So, why not remove that additional 10 lb weight and fly solo from the rear seat (CG also at 50Ē)? Letís see what it feels like.

CAUTION: CHECK YOUR AIRCRAFTíS CG BEFORE YOU TRY THIS

Here is the view from the back on the ground:

 

Right off you can see that there isnít a view over the nose, just out to the side; but, hey, that tail still comes up quickly so poor vis doesnít last long.

 

Once in flight visibility is fine and that long nose ahead of you gives a totally different feel.

 

Because there are two notches of flap and Iím climbing, the nose is higher than it would be in a faster cruise.

Taking pictures from the rear is easier too.

 

Now, solo from the rear, I have the landing characteristics of the more aft CG: minimal stick forces and no trim issues with the added plus of lighter weight.

 

On the other hand, as is, the S7 is not set up for this. The flaps and trim are not accessible, nor are the mag switches or fuel shut off (though on this plane I have the master and starter at the rear seat. Further, big winter boots are a little tight at the rear rudder peddles where, on the left side, the throttle linkage cramps the space.

 

So, the question is, should we re-work the S7 to make rear seat solo work properly?One big advantage is being able to move the battery forward which gives better accessibility, less weight due to shorter cables and improved electrical characteristics while not having to add lead or baggage when solo. On the other hand rear seat access to flaps means dramatic linkage changes or going to electric flaps. Also, rear seat instrumentation is no simple task either (it was nice to fly with that highly visible angle of attack indicator up front).

 

It turns out that going to dynamically balanced elevators has a big impact on stick forces with forward CG. One of my previous 94 S7ís had balanced elevators and large trim tab with electric trim and it was very acceptable while landing solo.

 

So, while it was fun to re-visit rear seat solo, I think I may just go to balanced elevators instead.

 

Letís head home:

 

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2009/01/29