---------------------------------------------------------- RV4-List Digest Archive --- Total Messages Posted Sat 10/16/04: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:42 PM - Re: Rivets on RVs (Alfredo Santoro) 2. 06:04 PM - >Re: Rivets on RVs (Oldsfolks@aol.com) ________________________________ Message 1 _____________________________________ Time: 03:42:16 PM PST US From: "Alfredo Santoro" Subject: Re: RV4-List: Rivets on RVs --> RV4-List message posted by: "Alfredo Santoro" Thank you Rob, Your answer has been really useful, and it's good news also! Because an RV 4 kit is less expensive, final result is better looking (in our opinion) and I do not need cabin room, being myself quite small. I understand from what you wrote that the RV 8 is not stronger than the RV 4, and that is what I needed to know, since I will like practicing a little of careful aerobatics with my plane, the day I will have one... The only issue that still makes me think about RV4 and RV8 is a message a pilot posted in Matt's Aerobatics List a few months ago. I will cite it here: >GUYS: Those of you who have RV's, and want to do acro. >From a long-time acro instructor. > ALL of the RV's are designed with prop shaft extensions, and please be >aware that this single factor is tremendously limiting in pulling any kind >of "G" with these planes, or in doing any kind of high-angular-velocity >changes. > Remember that the prop is a tremendous gyroscope, and as such, when you >introduce high angular rate changes, the forces on that gyroscope are >tremendous, and when you add in the moment arm of that prop shaft >extension, >you are placing unrealistic loads on the crankshaft. > If you continue with this action, the inevitable result will be, one >day, that your prop instantaneously departs from the plane. There will be >no warning, the crank will just break, and all that forward weight will be >lost. > Think about what that does to your CG, and then decide if you want to >continue doing any kind of serious acro in your RV's. > Van says that it is not an acro bird. He's right. It is a wonderful >plane, but it isn't designed for this kind of flight. >Lee Taylor" Then a guy answered: >Aerobatic-List message posted by: Ken Balch >Not true. While certainly the case with the earlier birds, the 'modern' >RVs (the -7 & -8, anyway) do not require the prop extensions. My RV-8 >(Lyc. IO-360-A1B6 & Hartzell c/s) doesn't have one. This was one of my >deciding issues when I built the plane: I didn't want a bird with a prop >extension. > >Regards, >Ken Balch >RV-8 N118KB >Pitts Model 12 N612KB (under construction) Now, I read that since 1993, RVs have been available with the short cowl option, which allows the use of a 2.25" extension rather than a 4" extension. RVs can also use either FP wood props or CS metal props, which have very different weights. So I guess that to have no worries at all about that torque I only need to make sure my RV 4 had the short cowl and short extension, and maybe a FP wood prop. Do you agree? Thank you. Alfredo. ----- Original Message ----- From: "rob ray" Subject: Re: RV4-List: Rivets on RVs > --> RV4-List message posted by: rob ray > > Hi Alfredo, > > I don't know what he was smoking, but it must have been good...ha! The > RV8 has improvements over the 4 in 3 areas, cockpit room, pre-punched > holes, thicker tail skins...period! As far as aerobatics,aesthetics, > athletics..etc go, the RV4 is superior, having personally extensively > flown aerobatics in both airplanes. The RV4 is smaller, lighter and > slightly more nimble in pitch. The wings internally are completely > different, the RV8 being along the lines of the "new RV's" with the one > piece spar billet. > The RV4/6 wing, back during RV6 certification in 1985 was subjected to > sandbag piling for intergrity for the FAA. At 9G's (150%) design load, > everybody left the room happy with no deformation or rivets popped. After > they were gone, they(Van's) continued to pile sandbags (for grins) to see > where or if it would actually fail. Where it finally broke was a well kept > secret, but one of the witnesses told me it was in excess of 11 G's and > even then it didn't break. The RV8 was only tested to failure at 9G's. For > my money, a layered spar is better for overall strength. Simply use .020 > skins on the tail surfaces, all else stock, you'll love the RV4.Yes it is > more work to build, but worth it. > > I don't know about you, but after 1400 hours, I still haven't gotten tired > of my 150HP RV4, and I get to fly F16's every now and again. Good Luck! > > Rob Ray > > Alfredo Santoro wrote: > --> RV4-List message posted by: "Alfredo Santoro" > > Hello, everybody. > I was thinking that some of you would sure be able to clarify me something > that I was told by an RV 6 builder that I met. > I asked him suggestions about building an RV 4, which is what I am aiming > to do as soon as possible. (Well, I am still at the decision phase about > what kit to purchase). > He was busy, during a home-builder meeting which I was attending as a > tourist or little more, so he explained me the thing rather quickly and I > am not sure I understood it well. > Basically, when he heard me talking about an RV 4 (which I love and had > enjoyed a chance to fly), he suggested me to prefer an RV 8, instead, > because of the different kind of rivets Van's adopted on it. > He said that the RV 8 type of riveting is completely different and makes > the structure stronger, expecially in aerobatics. > Is anybody of you able to explain me the differences among the two, and > confirm me this thesis? > > Thank you very much. > > Alfredo Santoro > Rome, Italy. > ________________________________ Message 2 _____________________________________ Time: 06:04:13 PM PST US From: Oldsfolks@aol.com Subject: RV4-List: >Re: Rivets on RVs --> RV4-List message posted by: Oldsfolks@aol.com I have built two RV-4's and have done just fun aerobatics in both. I used a 150 HP Lycoming with a wood prop on both. The first RV-4 had a 4" prop extension and the second has a 2 1/4" prop extension. The new finish kit has the cowl for C/S or fixed prop using a 2 1/4" extension. I had up to 5 1/5 G's positive and 3 1/2 negative on the first plane and flew 700 hours on it. I like the 150 HP RV-4 because I use a mixture of auto 87 octane and 100 LL avgas. This makes my flying more affordable. If you do smooth aerobatics,and pay attention to the manuvering speed you will be OK, I think. You'll love the RV-4. Bob Olds RV-4 , N1191X A&P , EAA Tech. Counselor Charleston,Arkansas Real Aviators Fly Taildraggers