EAA mag 1997 & RV's the greatest Kit plane of ALL TIME?
doneil said:
Ross
You mentioned "CFD plots on a 6A at 0 alpha". David Roberts
David I mentioned the reference above, April 1997 EAA article with the RV-6A CFD plots. Ross said he has his own CFD program he plays around with.
Kahuna said:
Boy do I disagree with this. There are MANY things he has not spent the time to consider and there are thousands of these flying with incredible mods that Vans has neither contemplated, nor implemented to improve his design. Van brought a basic design to the table which is a tremendous platform to improve upon. He is spending little time doing that. Good on all you guys who are making it better. Best,
Well I think we are looking at it differently.
"There are MANY things he has not spent the time to consider and there are thousands of these flying with incredible mods that Vans has neither contemplated, nor implemented to improve his design. He is spending little time doing that."
I am not challenging you but what specifically are you talking about? What mods are so great that they have changed the basic design or performance significantly?
Many mods I see builders make have nothing to do with the basic airframe kit, like engine/prop mods or the mods are trivial and have little affect on the plane. The exception, in my opinion, is the James cowl inlet/sealed plenum type set-up, which I see as worth while. Not a must but worthwhile.
Most mods are frosting on the cake. Sure builders like Dave Anders RV-4 is an example of taking a 220 mph RV and making it go +250mph. If you follow his work its beyond what most are willing to do, like using a highly modified engine with short engine/prop TBO's.
You say Van is not improving his design? Well the RV-7 and RV-8 are the improved versions of RV-6 and RV-4 respectively. That was some thing. Producing a value priced kit plane with more bang for buck is doing something.
He could continually change the design but at some point you have to freeze the design.
Heck he came out with the RV-10, pretty much a success from what I hear. It uses new construction techniques (composite/metal hybrid structure) and new airfoils, plus a 260 hp engine. The RV-9? In about 10 years he has come out with the RV-8, 7, 9 and 10. How many manufactures do you know who have made as many innovation. Now he's working on the RV-12. I don't think Van's aircraft is resting on their laurels and past reputation and not innovating all the time.
Van has gone back to the RV-3 and redesigned significant parts like the main spar. He has gone back to the RV-4 and made improvements to the engine mount, longer gear and elevator. The RV-6 got top hinged rudder pedals and the RV-7 got a big rudder and so on.
Van does improve the design adding safety and efficiency when needed. He has released 3 wing tips: Horner, shear and symmetric.
Clearly Pre-Punch is a quantum leap in kit value and construction. Also cowls are now epoxy/nomex. Van has made significant progress over the years in my opinion.
You could call me on the RV-6A/7A nose gear controversy. Van has changed the nose gear design recently (the new fork). Some think he should change the whole nose gear, kitandkaboodle. Another debate for another time.
Airplane designs as you know are a million compromises. I know you have done cool and extensive mods to your RV, like a 540 in a RV-8. Is it better? Sure more power is better, but in the big scheme of things a IO360 or now IO390 +200 HP RV is no slouch, even with 180HP or 160HP, you're faster than 90% fixed gear single engine cert GA planes (and many retracts). It's not that Van can't design a 540 RV-8, it's just he felt the "sweat spot" was with the 4 banger. Van is an engineer and like a Chess master thinks 20 moves ahead. Sure we see a mod as improving something, a no brainer, but he sees the affect overall. His conclusion of a mod's value may differ.
Van has been known as the "Flying Dutchman", where
Dutch means cheap. Van is also a frugal designer, not one to make elaborate complicate designs when simple work's. His personality comes out in his design. I think you're addressing personality or preference more than a lack of Van's design skills or thoroughness. I still contend its hard to improve on the basic airframe design or performance, and most "Improvements" are really frosting not the meat of the design.
Not sure specifically what you are talking about, but
in regards to cooling drag & cowl flaps I know Van has explored and tested them. I'm a huge proponent of the Barnard/James/Holly Cowl sealed inlet/plenum design. Why does Van not change his cowl and baffle kit? I don't know, but you can delete the cowl from your kit and buy a SJ cowl. Other factors may be involved, including inertia of manufacturing, why fix what ain't broke. To change major parts adds cost. Van's cheapness is good for us, other wise he would need to charge $40,000 like Lancair charges for their kits.
Did you know the first RV-6 prototype had an annular cowl inlet under the spinner (smiley face), verses the previous RV-4 axisymmetric dual inlets on each side of the spinner. Yep he tried to make the annular inlet work, but after much flight test he went back to the RV-4 design, as used on all current models today. Sure all his planes share common design characteristics, but so do Boeing jets. I don't think he is lazy but again why fix it what ain't broke.
Van wrote a series of articles in the RVator about cooling drag, cowl flaps and ways to improve the design for speed (in the 1993 time frame). He is a trained engineer and clearly his choices are well thought out? I know people complained about drawing inaccuracy or inconsistencies in the early days. Now that dwg and part fit is excellent. There will always be "WHY DID HE DO IT THAT WAY?" Some love Cam-Loks for the cowl verses the piano hinge. So what, its really an insignificant mod and the piano hinge has advantages, not the least of which is cost/weight.
Van is not here to defend his design. I'm sure 9 out of 10 times he would have good reasons for doing what he did. The 1 out of 10 times he may nods and says, good idea, but to get into the kit, it has to contribute a significant improvement with out adding cost, weight & build time. At air shows Van cruises the RV flight-line, when no one is watching. He appreciates SOME mods. Some mods make him shake his head. The KISS and KILL (keep it light lad) principals have their own rewards. Van's way is not the only way. I know that, and the joy of kit planes is modifing them, in part because we can. Nothing wrong with that.
Some mods have negative affect of adding weight, build time and cost.
Is there really a better kit plane on the market? Opinions will vary. With +5,000 flying, they all can't be wrong. I can say without reservation, RV's are the most popular and numerous high Perf kit planes in the sky. There really is no competition on the "total performance" horizon. Van has a fair and balanced design in my opinion even in stock form. Is it a perfect or optimal design in your opinion or mine? No but what's perfect.
We can agree GO forward and modify (carefully and safely).