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  #21  
Old 06-29-2020, 01:21 PM
AlpineYoda AlpineYoda is offline
 
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Originally Posted by RV8JD View Post
With this as a goal, pilots can gain this added level of enjoyment and use from their very versatile RV-3Bs, -4s, -6s, -7s, -8s, and -14s. ..."[/indent][/i]
Only 3, 4, 6, 7, 8 and 14s?

There go all my plans for rolling my future -10, mock dogfights, and sustained inverted flight.
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  #22  
Old 06-29-2020, 01:42 PM
sandifer sandifer is offline
 
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I've been a judge for the last 8 years and competed for 10 years through all the categories, so I do have some perspective here, but...

Quote:
Originally Posted by Jvon811 View Post
What I'm referring to little things like popping the stick between straight lines and radius'.
There's more than one technique which can achieve good scores, but the point here is to not be lackadaisical with your transitions and there's no such thing as one right way to do it. Done correctly, this is certainly nothing that causes irregular stress on the airplane.

Quote:
Originally Posted by Jvon811 View Post
Snap roll methods that judges seem to like even though they're not proper snaps.
I don't know what you mean by that, but the judging standards are biased toward actually DOING proper snaps rather than faking snaps. And there's no remote chance of faking a snap in anything but a carbon monoplane, and in my experience actual faked snaps in those aircraft receive majority HZ's from the judges. Certainly this does not apply to RVs, whether you want to snap them or not. It doesn't even apply to Pitts'. In any airplane where snap roll rate is 2-3x faster than aileron roll rate at the same speed, it's painfully obvious when a proper snap does not take place. No two pilots snap an airplane exactly the same either.

Quote:
Originally Posted by Jvon811 View Post
Can the RV do these things? Sure... But do I want to do them over and over and over in an RV? No.
Too bad you could not watch Ron Schreck, Jerry Esquenazi, or Bill McLean fly their RVs though Sportsman and Intermediate sequences. Their flying epitomizes smooth, and they always scored very well.

If you've been coached by a carbon monoplane driver who thinks all aircraft must fit into the carbon monoplane presentation style, then you've been led astray a bit. Rough jerking the plane around the sky and thrashing the controls certainly is not required.

Last edited by sandifer : 06-29-2020 at 01:45 PM.
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  #23  
Old 06-29-2020, 07:47 PM
RV8Squaz's Avatar
RV8Squaz RV8Squaz is online now
 
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Originally Posted by ronschreck View Post
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.

Please excuse my absence from this thread. I just got back yesterday afternoon form a 10 day trip out west in the Bonanza with the family. It was hoot!

Yes, it is I, Jerry Esquenazi, that had the canopy issues. Many people have snapped their RVs without any issues. I unfortunately, have had problems with my canopy which I believe was indeed caused by snap rolls. Most people are concerned about the tail. Who knew the canopy would be a problem?!

In Jan 2019, after being down for three weeks repairing a fuel tank leak, I was out doing snap rolls and rolling turns. I had attempted them before, but this was my first real practice with both maneuvers. I had done half a dozen of each and immediately following my last snap roll, I heard a loud bang. The canopy had cracked. It was 12" crack on the right side starting from one of the screw holes a few inches aft of my seat back. I was fortunate in that when I built my plane, I had assembled the canopy with screws instead of blind rivets. It made it much easier to replace the plexiglass without harming the skirt and the intricate paint job.

Did it crack because of the snap roll, some prior maneuver, or pure dumb luck? I don't know. At the time, my canopy was already 12 years in service, 15-16 years old since I purchased the finish kit. I already had a few hairline fractures around some of the screw holes, and it was quite cold for Georgia.

The airplane was down for 6 weeks while I replaced the plexiglass. In late Mar 2019 I went to my first Intermediate contest cold turkey. The snap rolls and lack of practice proved to be my nemesis. I then went to SNF and upon my return I set out to perfect my snap rolls. During practice, after about a dozen snap rolls to the left, my canopy popped open on the right side near the canopy bow. I had been seeing a glint of light from the corner of my eye to the right on every snap roll, but I thought it was just a reflection. In hindsight, I realize now that the canopy was opening slightly on the right every time I snapped. I suspect this was due to either air loads and torsion on the canopy or torsion on the fuselage. I purposely left the canopy untouched until after shut down. The latch was latched, the rollers in their tracks, and the aft center pin of the frame was fully seated in the block. Yet, the very aft end of the skirt where it rides over the center track, was pushed over about an inch to the left. I asked my coach to push on the canopy and it snapped back into place mostly. Something was deformed.

I suspect the canopy frame was deformed when it opened. Some have asked about my fuselage. I haven't taken any measurements, but there are no wrinkles in the skin, there aren't any popped rivets, the airplane flies straight and true, and my eyeball says it's straight. With that, I have had the canopy apart three times in the last year in an attempt to fix the issues. I've got it very close now, but it's not perfect like it once was.

I don't think it was a coincidence that I experienced a second canopy problem while doing snap rolls. Because of this I decided last year that I was no longer going to compete with my RV-8 since I don't feel comfortable doing snap rolls with it. Sure I can go back to flying Sportsman and avoid snaps. But now that I've tasted the challenges of Intermediate and hope to one day compete in Advanced, I've decided to focus my energy on getting the right airplane for the task. Some of my friends joked that I should try some snaps to the right to bend the canopy back into shape!

For the record I was doing my snap rolls at 90 kts and once I picked up the speed to 100 kts, never exceeding 3 g during the maneuvers. It sure did snap a lot nicer at 100!

I spoke with someone recently at a fly-in that had been receiving instruction from a highly experienced, nationally recognized, aerobatic instructor in their RV-8. Well into the course, they began doing snap rolls and the instructor sitting in the back seat was surprised to see movement, flexing, and deformation of the canopy during the maneuver. His canopy later cracked in an eerily similar location as mine.

I know that both Ron and Bill have had canopy issues with the cause undetermined. In Ron's case, the canopy actually cracked after a flight while sitting on the ramp!

I now have my canopy as good as it's going to get. I'm still enjoying aerobatics and have been watching the canopy carefully. I can do all of the Sportsman maneuvers including spins with confidence in the canopy. I'm not seeing any movement or flexing. That said, I hope the next snap roll I do will be in an Extra 300.
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  #24  
Old 06-29-2020, 08:22 PM
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ronschreck ronschreck is offline
 
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Originally Posted by skylor View Post
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
I see your point. Maybe it was just the sudden stops that eventually fractured the spar.
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  #25  
Old 06-29-2020, 08:44 PM
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ronschreck ronschreck is offline
 
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Default Aerobatics don't have to hurt!

Quote:
Originally Posted by Jvon811 View Post

... 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. ...
If you have ever seen a Cub or a Stearman perform a competition aerobatic sequence you would realize that popping the stick and crisp maneuvers do not necessarily win contests. The RV is a bit crisper than a Cub or Stearman and I would describe the typical aerobatic sequence as graceful. The following clip is my RV-8 doing an Intermediate sequence. Even the snap looks graceful rather than snappy or crisp. It scored well!

https://www.youtube.com/watch?v=gNNKnD2N5sI
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  #26  
Old 06-29-2020, 08:51 PM
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RV8Squaz RV8Squaz is online now
 
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Quote:
Originally Posted by sandifer View Post
I've been a judge for the last 8 years and competed for 10 years through all the categories, so I do have some perspective here, but...



There's more than one technique which can achieve good scores, but the point here is to not be lackadaisical with your transitions and there's no such thing as one right way to do it. Done correctly, this is certainly nothing that causes irregular stress on the airplane.



I don't know what you mean by that, but the judging standards are biased toward actually DOING proper snaps rather than faking snaps. And there's no remote chance of faking a snap in anything but a carbon monoplane, and in my experience actual faked snaps in those aircraft receive majority HZ's from the judges. Certainly this does not apply to RVs, whether you want to snap them or not. It doesn't even apply to Pitts'. In any airplane where snap roll rate is 2-3x faster than aileron roll rate at the same speed, it's painfully obvious when a proper snap does not take place. No two pilots snap an airplane exactly the same either.



Too bad you could not watch Ron Schreck, Jerry Esquenazi, or Bill McLean fly their RVs though Sportsman and Intermediate sequences. Their flying epitomizes smooth, and they always scored very well.

If you've been coached by a carbon monoplane driver who thinks all aircraft must fit into the carbon monoplane presentation style, then you've been led astray a bit. Rough jerking the plane around the sky and thrashing the controls certainly is not required.
Thank you very much for the compliment Eric. While flying smooth and not thrashing the controls and the airplane around, I do feel that I abused my airplane to some degree.

I sincerely believe the RV is perfectly suited for Primary, Sportsman, and is even capable of Intermediate, but I feel that my airplane was talking to me until it eventually yelled at me when the canopy almost departed. In the fall of 2018 I discovered a couple of loose rivets on the belly near the landing gear, then the fuel leak at left inboard rib in Dec 2018, then my canopy crack in Jan 2019, and finally the near canopy departure Apr 2019.

Except for a couple of minor over G, (6.2-6.3. The bottom of the box tends to that to some!), I always flew the airplane within its limits. Bill somehow always managed to keep it under 4 G, but I used most of the envelope regularly doing +5-5.5 to -2-2.5 and from zero to near Vne.

Perhaps it was the frequency of flying that I was doing too. It wasn't uncommon for me to practice 5-6 times/week. As the contest drew closer, I would practice every day, many times twice a day. I converted a lot of AVGAS into aerobatic figures. Maybe my RV wasn't up to that daily grind. I've got 1700 hours on my plane now, several hundred of which were flown as described above.

On the other hand, Ron had years of aerobatic competition and air shows amassing over 2000 hours on his airplane.
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  #27  
Old 06-29-2020, 09:54 PM
sandifer sandifer is offline
 
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Quote:
Originally Posted by RV8Squaz View Post
I converted a lot of AVGAS into aerobatic figures. Maybe my RV wasn't up to that daily grind. I've got 1700 hours on my plane now, several hundred of which were flown as described above.

On the other hand, Ron had years of aerobatic competition and air shows amassing over 2000 hours on his airplane.
Hey Jerry, I hear ya. And lest anyone feel "real" aerobatic airplanes hold up forever to acro, after 1900 hrs on my Pitts airframe, with lots of acro time all flown within limits, it ended up with half the nails worked loose from the leading edge, a broken drag wire block in the wing, and lots of paint cracks. Super Ds have a long history of cracked tank baffles, even without repeated snaps. It's just the territory we tread!
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  #28  
Old 06-29-2020, 11:40 PM
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skylor skylor is offline
 
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Originally Posted by ronschreck View Post
I see your point. Maybe it was just the sudden stops that eventually fractured the spar.
I suppose if it were really getting slammed against the stop the counterbalance inertia would cause that.

Skylor
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  #29  
Old 06-30-2020, 04:25 AM
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Gash Gash is offline
 
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Quote:
Originally Posted by sandifer View Post
I don't know what you mean by that, but the judging standards are biased toward actually DOING proper snaps rather than faking snaps. And there's no remote chance of faking a snap in anything but a carbon monoplane, and in my experience actual faked snaps in those aircraft receive majority HZ's from the judges.
Amen brutha! Monoplane snaps are a big deal to get right, and there’s no faking them in front of real judges. I spent an entire day—2 tanks of gas—with Bill Stein sitting on the ground coaching me through nothing but snap rolls. Sergei Boryak did the same thing the year prior. Talk about brain damage! These guys all know that to make a competent aerobatic pilot, they have to be “Mr. Miyagi” and make you do multiple hundreds of “wax on, wax off” repetitions before you can be the Karate Kid of snap rolls. There just ain’t no faking it.

Also, jvon811, I respectfully submit that 5 years of aerobatics on my RV-8 caused exactly zero cracks or defects. Also, 3 years of comparatively intense aerobatics in my Extra have caused zero cracks or defects in the areas you caution us Extra and MX drivers to look for. As long as one respects G and airspeed limitations, the airplane (RV, Extra, whatever) is going to be fine. Let’s not grasp for evidence where little exists, as this can dissuade aircraft owners from exploring and enjoying the full engineered potential of their flying machines.
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Last edited by Gash : 06-30-2020 at 04:39 AM.
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  #30  
Old 06-30-2020, 04:09 PM
dsowder dsowder is offline
 
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Default RVs and Aerobatics

I've flown RVs and think they're great, but I don't own one, so I hope you don't mind my comments. I've flown competition aerobatics for 27 years, have owned Pitts S-1, S-2B, and for last 15 years an Extra 300L. The S-1 was fixed pitch prop, the S-2B and Extra have counterweighted (i.e. "aerobatic") MT propellers.There's an important point to be made here: If you're planning aerobatics and any negative g time at all, I'd advise against a non-counterweighted (which is the usual) constant speed prop. These use oil pressure to force the blades to coarse pitch; if you lose oil pressure even briefly, the prop can go fine pitch and allow a massive engine overspeed at the speeds that an RV can fly.

I also fly a Lancair Legacy, which has a non-counterweighted prop and a Vne of 274 Knots. I don't even THINK about allowing the engine's oil pump to unport. This airplane is "just transportation".

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