Talk:Van's Aircraft RV-9

RV-9 derived from?

Three different IP editors 85.211.222.173, 85.211.99.210 and 85.211.225.202 have changed this article to indicate that the RV-9 was derived from the RV-6 and not the RV-7. The closest they have come to citing a ref is the edit summary comment the final time saying : "The RV-9A was created by joining a new wing to the RV-6B fuselage" Source 1998 4th quarter". This summary note about "Source 1998 4th quarter" doesn't mean anything - is that a publication of some sort?

I have found two refs, both from the Vans' website that give somewhat inconsistent information on this subject. RV-9/9A says:

“ What sets the RV-9/9A apart from other RV designs? In a word, the wing. It is longer and narrower than the wings of the RV-4/6/8 series, and uses a new Roncz airfoil. The increased span allows it to climb well on low power and glide a long way. The flaps are a long span, slotted, high lift design that allows the airplane to land slower than many primary trainers. A simplified constant-chord horizontal tail and large vertical tail are proportioned to work with the longer wing. The robust fuselage and cabin are identical to the RV-7/7A and there are the same sliding/tip-up canopy and trigear/tailwheel landing gear options. ”

This seems to indicate that, since it uses the same fuselage as the RV-7, which is larger than the RV-6 fuselage, that it was derived from the RV-7. Another Van's page, Introduction - About RV Kitplanes says:

“ The RV-9A, a side-by-side tricycle-gear design, was first flown in December 1997. A completely new wing with a higher aspect ratio and new airfoil gave excellent low speed flying qualities and very efficient cruise. Similar in size and weight to the RV-6, it cruises at about the same speeds, but stalls several miles per hour slower. This wing permits the use of lower-powered engines, providing an alternative for those who don’t feel the need for a "bigger, faster, more powerful" airplane. Somewhat later, the RV-9 tailwheel version was developed. ”

This ref says that the RV-9 is similar in size and weight to the RV-6 but doesn't give any information about the derivation of the design.

That same page indicates that the RV-9 was first flown in December 1997, while the RV-6 dates from "the early to mid 1980s". It says that the RV-7 was introduced in the "spring of 2001".

This is all odd. If the RV-9 uses the RV-7 fuselage then how was it flown four years earlier? If it is derived from the RV-6 fuselage with a new wing then why is it larger in fuselage width and height than the RV-6? It almost sounds like the RV-6 fuselage was enlarged for the RV-9 and then the same fuselage was used in the later RV-7 design, making the RV-7 a derivative of the RV-9 and not the other way around, but there is no info that I can find to back this up.

It is pretty obvious that all the RV series (except the RV-11 motorglider) are one common design, with evolutionary changes, from the original Stitts Playboy/RV-1 to the present RV-12. Perhaps it makes little sense to say that one was based on another, unless there is a citable ref that specifically states this.

In the meantime I have re-worked the intro paras to indicate the somewhat contradictory information that Van's provides and have cited both refs. Rather than any further edit warring on this, let's please discuss the refs here and see if we can come up with some text that makes sense given the sources that can be found and properly cited. - Ahunt (talk) 12:30, 21 September 2008 (UTC)

I have registered now. Thanks for the explanation and the time you took to write it. My ref was truncated. It should have said "The RV-9A was created by joining a new wing to the RV-6B fuselage" Source 1998 4th quarter RV-Ator magazine, written by Dick VanGrunsven the designer. I'll see what I can find out about the fuselage changes. 9Driver (talk) 15:27, 21 September 2008 (UTC)

Nice to have you on board. That would be helpful. As I outlined above the Van's website is pretty contradictory. - Ahunt (talk) 15:35, 21 September 2008 (UTC)

I think I found a good ref that explains the lineage of the RV-9 and its relationship to the one-off RV-6B. That article says"

“ To prove the concept, the company constructed an airplane that was something of a hybrid. Several years earlier they had built a one-off airplane called the RV-6B. It had a rectangular tailplane and a simplified wing spar that promised to be easier to manufacture. It also served as a test bed for a few other ideas. It flew quite successfully for a couple of years until a fuel sending unit failed and fooled the pilot into thinking he had more fuel than he did.

The engine quit at a very inopportune time, leaving no choice but a forced landing in a raspberry field. Raspberry vines are supported on short steel stakes that look a lot like those installed in fields during the second world war to prevent gliders from landing. They are very effective. Although the low landing speed and sturdy construction of the airplane allowed the occupants to emerge without injury, the airplane was badly damaged. The wings and tail were totally destroyed but the fuselage survived with just a couple of gashes and wrinkles. It sat in the corner of Van's hangar for a couple of years until he pulled it out to form the basis of the RV-9 concept.

The different spars in the RV-6B had worked well, and had greatly simplified the method of attaching the wings to the fuselage. Van combined the spar design with a new Roncz airfoil to come up with a wing like no RV had ever seen. New wings and a new tail were built for static load testing, and when they passed, another set was built and installed on the RV-6B fuselage.

When it came time to install the engine, Van had another surprise in store. Bucking a trend of ever more powerful engines that RV builders seemed bent on installing, he used an O-235 straight off the nose of a Cessna 152. In the clean airframe of the newly christened RV-9, it provided very good performance. The top speed was around 170 mph, and the long wing provided enough lift to get the airplane off the turf of Van's home strip in about 500 feet. After considerable test flying, spin testing and fine tuning, including a fly-off against a C152, the design was frozen and put into production.

While the prototype RV-9 was in the test programme, work was started on a kit prototype aircraft, built entirely from kit components. This airplane, registered N129RV, first flew at the end of June 2000. It is powered with an overhauled Lycoming O-320 of 160 hp (the largest engine specified for this design) turning a three-blade constant-speed MT propeller.

”

Based on this it really looks like they constructed a virtually new prototype using parts from the wrecked one-off RV-6B prototype, which was already somewhat different from the RV-6A production model. Based on the Van's website info that indicates that the RV-9 has a wider and higher fuselage (must have been modified from the RV-9 prototype) I am not sure that, based on this story, one can really claim that the RV-9 was based on any one model from the RV line, but was more an evolution of many past designs. - Ahunt (talk) 16:32, 21 September 2008 (UTC)

Userbox

If you fly an RV-9, please feel free to put this userbox on your user page!

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-Ahunt (talk) 15:44, 21 September 2008 (UTC)

flight stats

Where do the flight stats come from? I see in our info that the RV-9 has a max climb rate of 1,000 ft/min, but I know I have been in one at 2,500 ft/min, so I am wondering about the source for our current information. Googlemeister (talk) 21:09, 15 March 2010 (UTC)

You bring up a good point - they are unreferenced. I will update the format and reference it to the compnay specs and performance figures. - Ahunt (talk) 22:43, 15 March 2010 (UTC)