What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Van - A little help here!

ronschreck

Well Known Member
I sure wish Van would remove this wording from his company website.


"Although RVs are capable aerobatic aircraft, we do not recommend them for serious competition aerobatics. Their high speed is not suited to the restricted competition zones. In order to stay “in the box’’ they would have to fly slower and lose the benefit of inertia, or keep the speed up and pull too many Gs."

There are a lot of RV pilots flying in IAC competition who take issue with this. We stay in the box, don't over-G the aircraft and have done quite well against many purpose built aerobatic aircraft. We have the trophies to prove it!
 
Last edited:
Pat yourself on the back, you must be an exceptional pilot to be able to handle such an aircraft with such a terrible handicap....
 
Ralph, I'm not sure what you're trying to say there. Ron is simply stating a well-known fact in the International Aerobatic Club, that Vans RV aircraft are very capable, safe and enjoyable to fly in competition aerobatics. I competed in the RV-8 in Sportsman and won quite a few contests against a slew of certificated aerobatic airplanes. And so did Ron and many others. Ron is absolutely correct. Our RVs can easily stay inside a 1km square contest box while flying competition figures and not even getting close to a G limit. Most Vans RV pilots can fly the heck out of the planes and never go over 4 Gs.
 
Last edited:
Sarcasm

Ron,
I don't know where you found Vans statement about RVs not suitable for aerobatic competition. When I go to Vans home page, I see this:

AEROBATICS
The RV-4 has been flown in aerobatic competitions for years. It makes a great platform for weekend aerobatics, too. But please, get proper instruction!

Want to do some loops and rolls? The RV-8 is a fully aerobatic-capable airplane, stable and responsive. You'll even see RV-8's competing in sportsman and intermediate categories.

If you want to go beyond the Intermediate level, you'll have to move up to an aircraft designed for Advanced aerobatics like Gash has. I think Ralph is just being sarcastic and pulling your chain. HA HA I can't think of a better aircraft than an RV to begin competition aerobatics and enjoy the fun.
Bill
RV-4 slider
lower AL
 
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.
 
Excuse my probably failed attempt at humor.
I have great admiration to those that can make their RVs perform to that high standard. I also see Van's conservative stance as a valid advisory to those less skilled & untrained... like me.
 
thanks for reference

SPX, thanks for the reference, but agree with Ron and the other 20 or so RVers that have competed with their RVs. I know of 4 RVs that have competed at the Intermediate level, and two (Ron, and another, brought home some plaques). That said, the snap rolls may be adding additional stress with possible canopy damage, especially when initiated at and above max maneuvering speed.
Bill
RV-4 slider, 10 years of aerobatic competition:D
lower AL
 
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.
 
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.
 
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. :rolleyes:
 
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. :rolleyes:

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.
 
Rudder Stop Design

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. :rolleyes:

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 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.
 
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:
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.
 
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...
 
Last edited:
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.
 
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...

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.

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.

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:
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.
 
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.
 
Aerobatics don't have to hurt!

... 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
 
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.
 
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!
 
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.
 
Last edited:
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".

Doug Sowder
IAC 14590 Lifetime
 
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".

Doug Sowder
IAC 14590 Lifetime

Hey Doug!

Welcome to the RV Forum. We can use a bit of aerobatic expertise here.
Hope to see you at Nationals this year.
 
Do I need to rethink my inverted oil/fuel??

Dsowder posted:
"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. "

So if I hve a regular Hartzell, does that mean I shouldn't bother with fitting the inverted fuel & oil systems as I shouldn't be doing any negative G in the RV-8???
Or
Will the inverted oil system prevent the situation described by Dsowder from happening - is he referring to aircraft without the inverted oil system??

I had not heard this perspective before - and obviously installing a new prop as well as the inverted systems is a huge expense, which may not make sense for this aircraft.
Have many RV owners installed aerobatic props??? Ron???

Now I am wondering if I need to adjust my expectations for the RV8???
Thanks for any clarification etc
 
...
Have many RV owners installed aerobatic props??? Ron???

Now I am wondering if I need to adjust my expectations for the RV8???
Thanks for any clarification etc

As far as I know there are very few who have installed aerobatic CS props. I know that of all the pilots who flew on Team RV and Team Aerodynamix with me none had aerobatic props. In 10 years of competition aerobatics I have not come across a single RV competitor with one.

Your warning about over-speed is valid to a point. Yes, if oil pressure drops significantly you may get a rapid RPM increase. The engine noise will get your attention right away and even those flying formation next to you will hear it! It has happened to me on several occasions but I have always been able to snap the throttle back before things get out of hand. I have seen RPM jump to 3300 on occasion. Right now many of you are thinking ENGINE TEARDOWN! If you are a Pitts pilot you are thinking RIGHT ON! A momentary RPM surge is not a death sentence and many Pitts pilots keep the RPMs around 3300 all day long while flying aerobatics.

Having said this, I sure would have liked to have an aerobatic CS prop but I never figured the added expense was justified for the type of flying I did. It's a decision you will have to make on your own.
 
Snap Rolls

Since much discussion in this thread has been about snap rolls, I thought I would share a bit of my own experiences.

1. The plane does roll faster doing a snap roll at 90 knots than an aileron roll at 175 knots.

2. I get some canopy skirt "slap" during snap rolls. I have also experienced skirt slap during other high angle of attack maneuvers (I should say, high angle of attack maneuvers when well above the level flight stall speed).

3. Here's a brief clip of my doing a snap roll. I do aerobatics just for fun, but obviously if I were to fly in competition I would need to work on my stopping point a bit!

Snap Roll

Skylor
 
Nice use of the 360 camera. I do the same thing to help me debrief my acro flights. I have a small suggestion that might help your snap roll. I see that you're simultaneously applying left rudder and aft elevator. Pause your video at 0:09 and look at the rudder and elevator deflection. Also note how your nose traveled up and left diagonally prior to any stall buffet. So what you're really getting here is a buried rudder roll (possibly even a coordinated aileron roll) with both wings stalled as you go around. It's not really a snap roll. Also, watching the rear cockpit stick movement, it's hard to be sure, but it looks like you're not getting the stick full forward. It looks to me like you're only going back to a neutral pitch position. Tail view video seems to confirm this. If you pause the video at 0:10 and then pan the camera to the rear, you'll see that the elevator is neutral.

You might get more of a "snap" if you go full aft stick first, getting the wings past the critical AOA, and then briskly put the stick full forward and very slightly left (like an upside down J) while simultaneously stomping in full left rudder. You have to hit the rudder stop. It all happens really fast...like 1/4 second fast. Get that stick back, break the airflow over the wings, and very quickly get the stick full forward and slightly left, with full rudder deflection at the same time. Use two hands on the stick.

If this sounds a little like a spin entry, that's because a snap roll has very similar characteristics to a spin (aggravated stall with pro-rotation rudder held until you're ready for the insanity to stop). So why the need for the quick forward stick movement? That actually helps you "snap" around the roll axis quicker, just like when figure skaters bring their arms close to the body.

A common error is to not get the stick fully forward fast enough, thus causing more of a buried shoulder roll than a snap roll. Another common error is to not be full throttle...I couldn't tell from the video, but it seems like you are.

Finally, a safety nit pick here that's worth noting. It would be a real bummer if that headset and yellow towel under the rear seat harnesses were to come out during aerobatics and get lodged somewhere you don't want it (under a rudder pedal, etc.) Many have made this mistake, myself included. I once did an inverted safety check prior to diving into the box for a practice flight and a half-full water bottle hit the canopy!
 
Last edited:
Nice use of the 360 camera. I do the same thing to help me debrief my acro flights. I have a small suggestion that might help your snap roll. I see that you're simultaneously applying left rudder and aft elevator. Pause your video at 0:09 and look at the rudder and elevator deflection. Also note how your nose traveled up and left diagonally prior to any stall buffet. So what you're really getting here is a buried rudder roll (possibly even a coordinated aileron roll) with both wings stalled as you go around. It's not really a snap roll. Also, watching the rear cockpit stick movement, it's hard to be sure, but it looks like you're not getting the stick full forward. It looks to me like you're only going back to a neutral pitch position. Tail view video seems to confirm this. If you pause the video at 0:10 and then pan the camera to the rear, you'll see that the elevator is neutral.

You might get more of a "snap" if you go full aft stick first, getting the wings past the critical AOA, and then briskly put the stick full forward and very slightly left (like an upside down J) while simultaneously stomping in full left rudder. You have to hit the rudder stop. It all happens really fast...like 1/4 second fast. Get that stick back, break the airflow over the wings, and very quickly get the stick full forward and slightly left, with full rudder deflection at the same time. Use two hands on the stick.

If this sounds a little like a spin entry, that's because a snap roll has very similar characteristics to a spin (aggravated stall with pro-rotation rudder held until you're ready for the insanity to stop). So why the need for the quick forward stick movement? That actually helps you "snap" around the roll axis quicker, just like when figure skaters bring their arms close to the body.

A common error is to not get the stick fully forward fast enough, thus causing more of a buried shoulder roll than a snap roll. Another common error is to not be full throttle...I couldn't tell from the video, but it seems like you are.

Finally, a safety nit pick here that's worth noting. It would be a real bummer if that headset and yellow towel under the rear seat harnesses were to come out during aerobatics and get lodged somewhere you don't want it (under a rudder pedal, etc.) Many have made this mistake, myself included. I once did an inverted safety check prior to diving into the box for a practice flight and a half-full water bottle hit the canopy!

Thanks for the input. It's definitely not a coordinated aileron roll because the ailerons remain neutral until I inadvertently apply "out-spin" aileron during the stop/recovery...but it may be a bit of a buried shoulder roll. I have done some other ones where I have managed to delay the rudder kick until after application of elevator. I haven't worked up the courage to get the stick more forward than about the neutral position during the snap...I am applying full throttle just prior to the elevator.

Good call on the headset and "seat protector" towel. They seem pretty secure under the belts but they probably could be jarred free. Next time I'll take them out.

Skylor
 
Skylor, I might offer an alternative take on the snap roll. In your video, you definitely did a snap. You cannot mistake a snap for a shoulder roll since a shoulder roll is a very uncomfortable negative G roll with a much slower roll rate. A real snap is a smooth ride under nearly zero load in your seat. Producing a shoulder roll rather than a snap is caused by unloading the stick forward of neutral and applying in-spin aileron after failing to produce a snap break. This is usually caused by being too late on the rudder and unloading too early. If the snap breaks at all, it's not going to shoulder roll, even if you don't unload at all. In this case, you'll "bury" the snap and the rotation will be slow, but that's different from a negative G non-snap shoulder roll.

In your video, the main thing to tighten up is your stick movement. You should apply the aft stick MUCH more quickly. Keep in mind that your hand moves faster than your feet, so be careful to avoid being late on the rudder as you speed up your stick input. Consider the elevator and rudder movements as made simultaneously, and you'll naturally lead slightly with the elevator, which is proper technique. You did unload as the snap broke. I'll differ from Karl and suggest trying to AVOID using full deflection elevator inputs both in the initiation and the unload. I've never flown an airplane that required full aft elevator to do a good snap. The cleanest, fastest, lowest energy loss snaps are actually done with the LEAST amount of elevator input as your airplane will let you get away with. In most airplanes that snap half decent, you can do great snaps using less than half aft elevator deflection if your technique is good. RVs may need a little more than some more dedicated acro types, since RV wings really love to fly. Ron Schreck would be the man to advise you on RV-8 snaps in particular.

Regarding snap technique in general, you do NOT need to stall the airplane or necessarily even pull to the buffet on the snap entry. You only need sufficient AOA for the rudder input to THEN cause one wing to stall. If you unload the stick at just the right moment as this happens you'll get that nice clean explosion into the snap. It's a shocking difference the first time you happen to hit the inputs perfectly. The quality of the snap is amazingly sensitive to minuscule changes in the timing of all the inputs. Excessive elevator input just adds excess stress to the airplane, and causes higher drag and more energy loss through the snap. If you want to compete and get good snap scores, you'd need to be sure to show sufficient pitch change to the judges 2,000' below you, but that's another topic.

Regarding the unloading of the stick, most airplanes will do a great snap just by returning the stick to neutral. I've never flown an airplane that required full forward stick on the unload to do a good snap. Universal snap technique involves moving the elevator to a degree forward of neutral, but lots of airplanes have a point where any more forward elevator than necessary does not contribute further to the acceleration of the snap, and only adds excess drag.

Traditional snap technique also involves adding some in-snap aileron along with the unload of the elevator. Just be sure not to add any in-snap aileron until you start the elevator unload movement. The stick movement can be made like a "check" mark - pull straight aft, then in a diagonal line forward with the aileron. Get the aft elevator in and out as quickly as your airplane will let you get away with. You can experiment to see what effect varying amounts of elevator unload and in-spin aileron have on the snap rotation. But you should find that it's minor. The snap is mostly driven by the stalled wing and you can do quite nice snaps by unloading to neutral and adding no in-snap aileron. Some aileron and forward stick should accelerate the rotation a little though. The Pitts for example is generally quite insensitive to various amounts of forward stick and in-snap aileron, meaning you cannot turn a weak snap into a significantly better snap just with the aid of aileron....unlike what our carbon monoplane friends can get away with. :)

Also, read Alan Cassidy's book. Excellent coverage of the snap...and all the other maneuvers too. By far the best acro book out there.

And FWIW, a tail view of some snap inputs I shot in the Pitts years ago. About 2/3 elevator deflection both ways.

https://www.youtube.com/watch?v=TUH1lyerTio
 
Last edited:
Since we're talking aerobatic technique:

What entry speed and rudder-kick speeds do the aerobats here suggest for hammerheads in the RV-8?
 
Since we're talking aerobatic technique:

What entry speed and rudder-kick speeds do the aerobats here suggest for hammerheads in the RV-8?

Entry speed is whatever allows you to get to vertical without stalling or falling out. You could do this from 100mph or from Vne, it doesn't matter. Entry speeds don't matter for the basic figures. Low cruise works for anything in an RV. Regarding when to kick, airspeed indication is not a good way to learn to do a good pivot, since airspeed will be dead by the time you need to pivot. If you're using airspeed as an indicator, you're going to be kicking early, and 'flying' over, meaning a large radius rather than the ideal minimal radius pivot.
 
Entry speed is whatever allows you to get to vertical without stalling or falling out. You could do this from 100mph or from Vne, it doesn't matter. Entry speeds don't matter for the basic figures. Low cruise works for anything in an RV. Regarding when to kick, airspeed indication is not a good way to learn to do a good pivot, since airspeed will be dead by the time you need to pivot. If you're using airspeed as an indicator, you're going to be kicking early, and 'flying' over, meaning a large radius rather than the ideal minimal radius pivot.

Ok then if not airspeed then what do you use for the decision?

I was taught to do hammerheads in a Super Decathlon. There, I was told to wait until the corkscrew slip stream of the prop slaps against the fuselage - you feel a wobble, or vibration. Then kick.

So what's the signal for the hammerhead kick on an RV-8?
 
Ok then if not airspeed then what do you use for the decision?

I was taught to do hammerheads in a Super Decathlon. There, I was told to wait until the corkscrew slip stream of the prop slaps against the fuselage - you feel a wobble, or vibration. Then kick.

So what's the signal for the hammerhead kick on an RV-8?

Here are two techniques you can try for hammerheads in the RV-8. These both worked fine for me while flying in contests, and I never had any problems "flying over".

1. When flying the upline, as you decelerate, you'll eventually need aileron to counter the tendency to torque roll. Looking down your left wing, when you see aileron starting to go up, kick the rudder. This technique is a little subtle, so you can always fall back on 2. below:

2. It's true that airspeed is not a great crutch to use, but it does work once you find the right number for your airplane and you get some feedback from somebody watching on the ground. On my RV-8, as soon as I saw 40 KIAS, I would kick the rudder. I got high scores with this.

Some math here. By the time you're well into your hammerhead pivot, you will have decelerated to something less than 40 KIAS. Let's conservatively estimate that you're now down to 30 KIAS (although you're probably slower). At 30 KIAS, you're traveling 50.6 feet per second. You're not going to "fly over" 2x your wingspan at this velocity as long as you keep the pivot turn going until you're vertical down.
 
Last edited:
Since we're talking aerobatic technique:

What entry speed and rudder-kick speeds do the aerobats here suggest for hammerheads in the RV-8?

I tried the string on the wingtip but that didn't work well.

I observe the airspeed indicator and count two potato after the needle passes 40 knots then kick rudder. With practice you will discover how many potatoes your airplane requires.

Eric Sandifer has already discussed entry speed.
 
Last edited:
I observe the airspeed indicator and count two potato after the needle passes 40 knots then kick rudder. With practice you will discover how many potatoes your airplane requires.

The secrets are now coming out! I take back the ASI comment for RV hammers based on Bill and Karl's feedback. :)

Saville, the clues available for pivot timing vary a bit between aircraft types, and it's whatever consistent method you can find that works. As Karl mentions, some airplanes will start to torque roll as you slow to the pivot, and you use aileron input as a gauge. This is also the most useful method in a Pitts. Some airplanes produce a slight airframe or tail buffet as the prop slipstream tightens at or near the pivot point. The drumming belly fabric is the classic method in the Super D, as you've already learned. You can also tie a string to the sight gauge and observe the flicker pattern as you reach the proper point. This works better for some than others, also depending on aircraft type, as Ron observed. Increasing right rudder is required to control yaw as the airplane slows and could possibly be used as well. I believe Bill McLean said at one point he gauges right rudder deflection in his RV-4.

Besides airspeed indication, those are all the methods that I'm aware of. It seems ASI can be a tool for the RV. The usefulnesss of airspeed indication depends on how slow the airplane can get before pivoting. High power-to-weight ratio ships with powerful rudders (Extra/Pitts types) can practically come to a stop at the pivot. Airspeed cannot be used here. It could be an aid for planes that must begin pivoting with more airspeed. If you can find a way to do it consistently with your eyeballs outside the cockpit the whole time, that's ideal. Ground coaching is needed if you really want to learn to pivot with the tightest radius, but it doesn't matter of course for funnin' around acro.
 
Back
Top