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  #11  
Old 06-28-2020, 05:11 AM
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ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gilbert, AZ
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Originally Posted by jls32 View Post
I know of only one RV to fly Intermediate and he broke his canopy on snaps.

I think the RV is easier than a Super D thru Sportsman. Most Super D?s won?t snap and stop at Sportsman.

I plan on inverted fuel but not oil for easy acro.
I know of the RV you refer to that "broke" the canopy. Actually the canopy didn't break but the frame somehow torqued and came out of alignment and we're not sure it was as a result of doing snaps. Personally, I have snapped my RV-8 hundreds of times with no ill effects. I stay well below maneuvering speed (122 knots) and find my sweet spot for snap entry is 100-110 knots. I have never seen more than 3.5 Gs during snaps.

BTW, for easy acro you won't even need inverted fuel. You might look into a half Raven system to catch your vented oil though. That will work better than any air/oil separator on the market.
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  #12  
Old 06-29-2020, 03:52 AM
RhinoDrvr RhinoDrvr is offline
 
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Location: Lemoore (Fresno), CA
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Ron,

Just for my curiosity. Did you find any horizontal stab cracks when completing the service bulletin? I don?t snap (or really slip) my RV because of potential stress on the vertical / horizontal stabs. Curious if your airplane exhibited the cracks described with regular snap rolls. If not, perhaps I am being too conservative.
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  #13  
Old 06-29-2020, 04:39 AM
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ronschreck ronschreck is offline
 
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Originally Posted by RhinoDrvr View Post
Ron,

Just for my curiosity. Did you find any horizontal stab cracks when completing the service bulletin? I don?t snap (or really slip) my RV because of potential stress on the vertical / horizontal stabs. Curious if your airplane exhibited the cracks described with regular snap rolls. If not, perhaps I am being too conservative.

I accomplished the stabilizer SB 14-01-31 repair to my RV-8. I did find cracks but I wouldn't necessarily attribute this to snap rolls as many other RV-8s have been found with similar cracks on airplanes which have never been subjected to aerobatics of any kind.

Done properly I don't think snap rolls impose any undue stress on the airframe. I never exceeded 110 knots on entry and I never hit the stops on any controls. I never saw more than 3.5 Gs.

Hammerheads are another issue. I broke the control horn off of my rudder because I regularly hit the rudder stop. After a few thousand hammerheads the horn tore loose from the rudder spar. I replaced the rudder and have since learned that going to the stop is not necessary or advised. Live and learn.
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  #14  
Old 06-29-2020, 10:05 AM
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Jvon811 Jvon811 is offline
 
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I broke the control horn off of my rudder because I regularly hit the rudder stop. After a few thousand hammerheads the horn tore loose from the rudder spar. I replaced the rudder and have since learned that going to the stop is not necessary or advised. Live and learn.
It's a good thing you did live and didn't need to join the Caterpillar Club. Not to beat this dead horse anymore than it already has been on VAF, but I think you inadvertently just illustrated a point that a lot of non-IAC Competitor and many RV owners feel.

I am NOT saying that Competition-style Acro is unsafe in an RV or can't be done. I just don't think it's really built for it. I don't get my -4 out of the hangar without going upside down at least a few times every flight. I love it, please don't get me wrong. But after a couple hours flying Pitts' and Lasers' and other machine's built for that, I like flying an airplane that I know is going to be able to take more than I can. I'm actually shopping around and thinking about getting a good S-1 as an RV stablemate just so I can start competing. I just don't get the warm fuzzies about hitting the stops in my RV on the regular. I think a lot of RV owners probably feel the same way including Van himself. Hence the language on the website.
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  #15  
Old 06-29-2020, 10:05 AM
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skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
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Quote:
Originally Posted by ronschreck View Post
I accomplished the stabilizer SB 14-01-31 repair to my RV-8. I did find cracks but I wouldn't necessarily attribute this to snap rolls as many other RV-8s have been found with similar cracks on airplanes which have never been subjected to aerobatics of any kind.

Done properly I don't think snap rolls impose any undue stress on the airframe. I never exceeded 110 knots on entry and I never hit the stops on any controls. I never saw more than 3.5 Gs.

Hammerheads are another issue. I broke the control horn off of my rudder because I regularly hit the rudder stop. After a few thousand hammerheads the horn tore loose from the rudder spar. I replaced the rudder and have since learned that going to the stop is not necessary or advised. Live and learn.
Did your -8 have the stock rudder stops or some alternate design of stop? Since the stock rudder stop is designed to contact the horn itself, hitting the stop should not cause additional load to be transferred from the control horn to the rudder spar.

Skylor
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  #16  
Old 06-29-2020, 10:42 AM
sandifer sandifer is offline
 
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Originally Posted by Jvon811 View Post
I am NOT saying that Competition-style Acro is unsafe in an RV or can't be done. I just don't think it's really built for it.
But do you actually have competition experience? I don't see you in the IAC records unless your activity pre-dates '06. I only bring this up because nearly everyone who makes these types of statements above don't have experience with, nor really understand the sport and how to fly the maneuvers such that they score well.

Non-competition pilots of RVs do all the Sportsman level maneuvers all the time (and some Intermediate as well) just recreationally, messing around by themselves having fun. There is nothing about flying these same maneuvers simply such that you stay inside a box area, fly X and Y headings, draw accurate 45 deg and vertical lines, fly round loops, center rolls on a line, stop spins on heading, etc. that require abusing the airplane or stressing it beyond its design limitations.

We need to get over this idea that only airplanes "designed" for competition should compete. Very few actually were. Even the Pitts was not "designed" for competition. There is huge diversity among the types that compete. Only RVers themselves for some reason are consistently compelled to disparage their suitability without first really understanding the sport.
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  #17  
Old 06-29-2020, 11:56 AM
jls32 jls32 is offline
 
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Location: Denver, CO
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Originally Posted by AlexPeterson View Post
How does this make sense?
Not sure what you?re asking. ?Lite acro? as in not sustained inverted so no need for the heavy inverted oil system just a light flop tube for fuel to keep it running while floating at the top of a loop.
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  #18  
Old 06-29-2020, 12:05 PM
sandifer sandifer is offline
 
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Originally Posted by jls32 View Post
Not sure what you’re asking. “Lite acro” as in not sustained inverted so no need for the heavy inverted oil system just a light flop tube for fuel to keep it running while floating at the top of a loop.
If you're running fuel injection, the charge of fuel in the lines alone will keep the engine running plenty long enough for temporary zero or neg G exposure, especially if it's so short in duration that you're unconcerned about having inverted oil. If this is all you're going to do, and you have FI, a flop tube is pointless. And if you're running a carb, a flop tube won't help unless it's a pressure carb.

Last edited by sandifer : 06-29-2020 at 12:09 PM.
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  #19  
Old 06-29-2020, 12:23 PM
jls32 jls32 is offline
 
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Originally Posted by sandifer View Post
If you're running fuel injection, the charge of fuel in the lines alone will keep the engine running plenty long enough for temporary zero or neg G exposure, especially if it's so short in duration that you're unconcerned about having inverted oil. If this is all you're going to do, and you have FI, a flop tube is pointless. And if you're running a carb, a flop tube won't help unless it's a pressure carb.
Not necessarily. Depends on how long the fuel pump is unported. I?ve had inverted oil systems lose pressure long enough that it may have caused a burp in the fuel. I don?t think it?s a big deal but nice to avoid. I flew acro in my Cassutt that had a float carb so used to the engine coughing on loops and rolls.
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  #20  
Old 06-29-2020, 01:20 PM
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Jvon811 Jvon811 is offline
 
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But do you actually have competition experience? I don't see you in the IAC records unless your activity pre-dates '06.
Have I actually entered a contest so that I may validate any credibility on the subject? No, I have not. But I have been exposed to IAC judging and critique and flown sequences that have been critiqued. I know what the sport is. I'm aware of the history of the sport, what a good performance looks like and would like to enter contests myself someday to perfect those skills in front of judges. Just not yet, because all I have is my RV...

What I'm referring to little things like popping the stick between straight lines and radius'. Snap roll methods that judges seem to like even though they're not proper snaps. All sorts of things that make a sequence look crisp to a judge on the ground. Can the RV do these things? Sure... But do I want to do them over and over and over in an RV? No.

Look at the aileron hinges (and number of hinges) on an MX or Extra, or the strap hinges some aircraft have such as a One Design on the tail surfaces, versus the tiny rod end bearing's put through a hole in some sheet metal (which are known to sometimes crack) on the RV's. There are a lot of forces on the aircraft that happen in competition style flying (not to mention adrenaline) that might not happen on a lazy afternoon session in my RV. My opinion is that it doesn't take a veteran, documented, competition pilot to be able to see the structural differences. I want my airplane to last longer than I will without the fear of breaking rudder horns or anything else. I don't think I'm alone with that opinion weather the RV pilot knows the sport and has flown in an actual contest or not.

I also know the opposing view to everything I've written... "Well there are plenty of clipped wing cubs and other non-stout or beefy monoplanes that compete all the time. You don't have to fly hard like Mike Goulian or Rob Holland to compete." And you're right. I reserve that flying for my lazy afternoons. But to compete, it'll be a purpose built airplane, someday...
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Last edited by Jvon811 : 06-29-2020 at 01:28 PM.
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