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Vortex Generator - VG's

Wayne

Wayne

Well Known Member
Anybody have any experience with VG's on their -10?
I know the -10 handles well but I'm trying to improve elevator authority while landing. (I have a 40lb sack of sand in the baggage compartment now)
My previous experience adding vg's to my beech musketeer resulted in noticeable difference in slow flight handling but more importantly, it gave better elevator authority while flaring - all without negative effect on speed.
 
zig zag tape on stabilizer?

You might consider trying zig-zag tape on the stabilizer, on the underside, an inch or so forward of the hinge line. This energizes the flow over the elevator and usually improves the control power at large elevator deflections.

You can buy zig zag tape from Wings and Wheels I think, a sailplane accessories supplier. It is self adhesive, so only takes a few moments to put on, and if it doesnt work, its easy to take off.
 
AviatorJ said:
Are RV-10's typically forward heavy?
Click to expand...

Each RV-10 is different. Mine came out a little tail heavy initially. And it was very nice to land while solo. However, I could find myself past the aft CG limits in certain loading scenarios.

For that reason, I moved the battery to the firewall to get all my loading scenarios to a happy place. The consequence of that action is that landings while solo are a bit different. I have to use almost all of my up trim on landing, or I can add a 25 pound bag of shot to the baggage compartment. Landings with any load in the back seats or baggage compartment don't require nearly as much up trim.

At no time have I left I was out of elevator authority. The usage of all the up trim is simply to reduce the back pressure required on the stick in the flare.
 
Make sure your elevator has full up travel specified in the plans. Mine is a little nose heavy also.
 
AviatorJ said:
Are RV-10's typically forward heavy?
Click to expand...

Yes with empty back seats the CG is very forward. Handles and lands fine without wieght, but you will have the stick ALL the way in your crotch and significant stick forces if you have no weight in the back. Add even 20 lbs in the baggage compartment and it helps. Most of the time I do fly without anything in the back just because I am too lazy to add anything most of the time, or just don't think about it. Not a big deal, but some weight does help when flying solo or with a copilot.
 
AviatorJ said:
Are RV-10's typically forward heavy?
Click to expand...

Short answer, no.

My most forward CG (solo, low fuel and no baggage) is at 108.8" . My most aft CG at gross with four 170# FAA people and baggage is 114.98. Approved CG range is 107.84" to 116.24".

Bottom line - build per plans and not go crazy with adding weight you get a very predictable airplane.

I do note however that the HS dynamic tail down force is a little more than needed, as evidenced by the elevators slight trailing edge low in cruise. I added a 0.063" shim under the forward HS spar to increase the HS angle of incidence. It could use a little larger shim but then I'd have to replace the empennage fairing - not something I want to do.

Carl
 
AviatorJ said:
Are RV-10's typically forward heavy?
Click to expand...

As others have noted, the answer is 'yes', especially for minimalist interiors (adding interiors typically moves cg aft). IMHO this is what you want. I need 16 lbs in the baggage area when solo (short legs so my seat is nearly full forward) which is easily done with a plastic jug of water. If I pick up passengers I dump the water out. This gives max possible cg range, because you do need to watch the aft limit with rear passengrs and baggage. Also, you must check zero fuel cg - it is usually worse than with full fuel.
 
Carl, since elevators 'fly upside down' (produce down force) didn't you mean DECREASE angle of attack with a shim under the forward spar?
 
Carl Froehlich said:
I do note however that the HS dynamic tail down force is a little more than needed, as evidenced by the elevators slight trailing edge low in cruise. I added a 0.063" shim under the forward HS spar to increase the HS angle of incidence. It could use a little larger shim but then I'd have to replace the empennage fairing - not something I want to do.
Click to expand...

It is purposely designed to be that way. It improves pitch stability. They are experimental airplanes so builders are free to do what they want.... just pointing out that it is not a mistake. If you change it, you are changing the handling and stability quality's of the airplane

Some of the single engine Cessnas are designed to fly with a small amount of nose down elevator (C-182 is one example). Cessna went to the trouble of slightly offsetting the counterbalance arms on each elevator so that they are inline with the hor. stab in flight.

The RV-10 is not like that because it would make the elevators more complex to build and it requires a different tip fairing for the left and right sides.
 
elevator shim....

Carl & Bob, I am a bit confused. If the "normal" RV10 has the elevator trailing edge down (i.e. the elevator is trimmed to create more lift in the tail), then to match that with a change in HS pitch, I think Carl has it right. HS may fly upside down, but then elevators do as well, two upside downs = normal? Maybe a good movie title too.:)
 
Stick force gradient or stick-free stability

Scott is correct that a well balanced design should cruise with slight trailing edge down elevator when the elevator force is trimmed out. This is important to prevent stick force reversal at low speed.
 
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