Razor Back Option

[dginok]

I'm trying to decide whether I should install this on my Super Sport. Does anyone have an opinion regarding this feature, whether it is useful/desirable?

[Dick B in KY]

From pure asethics it looks good, is not hard to install. Don't know if it helps increase anything or not (haven't flown my SS yet).

Dick B

[dginok]

Thanks Dick!

[MotReklaw]

I like it too, but no experience with how it performs.

[jtpitkin06]

The razorback option applies to the model 7 SS. It is a 3 inch high dorsal fin extension to the vertical stab reaching forward and tapering to zero height at the rear of the baggage compartment.

According to the supplement in the builder's manual it "does add to the yaw stability of the aircraft."

The option is made from a 5 foot long piece of aluminum tube and a plywood rib. The parts weigh about 7 ounces. The increase in fabric is negligible.

This photo shows the razorback tubing and the plywood support. It is bonded in place with Hysol at the rear. The front end of the tube slips over a weldment and is bonded to a fuselage cross member.

John Pitkin
Greenville, TX

[Geowitz]

Ahh yes, I just always called it a dorsal fin. Thanks.

[RV6flyer]

The razorback option applies to the model 7 SS. It is a 3 inch high dorsal fin extension to the vertical stab reaching forward and tapering to zero height at the rear of the baggage compartment.

According to the supplement in the builder's manual it "does add to the yaw stability of the aircraft."

The option is made from a 5 foot long piece of aluminum tube and a plywood rib. The parts weigh about 7 ounces. The increase in fabric is negligible.

This photo shows the razorback tubing and the plywood support. It is bonded in place with Hysol at the rear. The front end of the tube slips over a weldment and is bonded to a fuselage cross member.

John Pitkin
Greenville, TX

Were you able to bend the tube by hand?

[HighWing]

I know of guys that are incorporating this idea on the earlier models as well. I have been told that it simplifies the fabric covering in that area. One thing on the IV, there is usually antenna mounting plates on the top surface of the fusalage, and extending the dorsal fin to the turtle deck will eliminate the use of these mounting plates. If going all the way forward, I would suggest cutting them out for weight savings. I terminated mine just aft of the forward plate as I still wanted the com antenna to be mounted there. For weight savings I also eliminated the wood rib most guys are using as I sort of thought that it was a bit of overkill as the linear length of the shrinkable fabric on each side of the tube is less than a foot and shrink pressure on the aluminum stringer would be minimal. I glued a couple of aluminum stand-offs under the rib similar to the stand offs on the side stringer - no wood there and longer runs between standoffs.

Keep in mind that for the IV, it is not a kit option, but a builder design option and I am trying to work toward simple and light.

Lowell

[RV6flyer]

This is what I just did to my 5 project. Bonded with epoxy and flox. The tube is bonded at the forward edge of the antenna mount plate and at that a small rib about midway. Sorry about the rotation. It is OK in m file. Do not know how to fix this.

B287BC98-3DDE-4C82-AEAB-8A0960801C03.jpeg