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RV-4 aerobatics question...

FLY6584

I'm New Here
I'm interested in purchasing an RV-4. It will primarily be used for fast economical x-country transportation, but occasionally I'd like to take some friends up to do some aerobatics.

Is that even possible? I'm 200lbs so is it possible to perform aerobatics with a rear passenger and if so what kind of weight will that person be limited to and what kind of fuel load will I be limited to?

Thanks!
 
passengers and aerobatics

In a RV-4, I would not recommend aerobatics with a passenger regardless of their weight except an aileron/ barrel roll (clearing maneuver, no Gs). I've had my RV for 10 years and even with a good looking 120 lb. passenger strapped in, the pitch becomes so sensitive, you can very easily overstress the airplane before you know it. With a 200 pounder, it's a nightmare. Also, when you go zero to negative Gs and into positive, there is a slight lag before their butt hits the seat which really increases the pitch. Then there is the weight of the required parachutes. If you search on this site, you can find this discussed before. Would recommend a RV-8 or a side by side (RV-6-7-14) for any dual aerobatics. By the way, puke on the back of the head ruins the mood.
Bill McLean
RV-4 slider
lower Alabama
 
Lol. Good to know. I've been doing a lot of reading and it seems pretty split. Some people say no way and others say good to go as long as they aren't too heavy and you keep it to the minor stuff.
 
There's an aerobatic maximum weight that's below your normal, allowable gross weight....don't know what it is for the -4 but the RV-6 has a normal gross of 1600 lbs, IIRC, and an aerobatic maximum of 1350 lbs, so check the manual or someone on here may chime in.

Best,
 
Aerobatic gross weight for the RV-6 is 1375 lbs. I believe for the -4 it's 1275.
I could be wrong on the -4.
On the other hand, there have been people get into trouble doing aerobatics in a -4 with an aft CG.
I do not recommend it at all!
 
Well you will get varied opinions so I'll offer contrary view. The -4 is more sensitive in pitch with some one in the rear seat. Simple flight dynamics dictates a conventional aircraft will get more pitch sensitive with a more aft CG location. But how sensitive is too sensitive? The answer to that one is subjective and varies with pilot and experience.

When I first flew the -4 I noticed the change of pitch sensitivity a lot when someone got in the back. Now I just don't seem to notice it. I can tell its there but seem to adjust without noticing it all that much. I don't consider myself some super stick jock but I wouldn't be a pilot worth being called that if I didn't think I was "above average". Maybe I should have grown up in Lake Wobegone?.

As others have pointed out the critical limitation is the aerobatic gross weight. Start with a 200 lb pilot, add in a normal sized backseater, and pretty soon you don't have room for go juice. But assuming you can make the numbers work I see no reason not to do aerobatics with a passenger in a -4. Since its probably not nearly as much fun for them as it is for you the question might well be - "Why would you want to?".
 
Aerobatic gross weight for the RV-6 is 1375 lbs. I believe for the -4 it's 1275.
I could be wrong on the -4.
On the other hand, there have been people get into trouble doing aerobatics in a -4 with an aft CG.
I do not recommend it at all!

Mine (RV-4) shows 1375 lbs
 
I think it’s safe to say that the CG is no more or less important than the Gross weight, both are critical.

As far as the go juice, some have stated including the tall soft spoken fellow himself that with the use of some prudence and common sense the weight of fuel in the wings could be eliminated from the gross aerobatic weight calculation.

Every one of these RV-4s has a different empty weight and different CG, you need to run the numbers for what you want to do in whatever airplane you’re looking at and use your best judgment based on the math and your skills.

I have found that some passengers enjoy a roll and a couple of big steep wingovers very much, all done legally with shoots etc.
 
with the use of some prudence and common sense the weight of fuel in the wings could be eliminated from the gross aerobatic weight calculation
Pure physics would state this might have some validity if, when you overstress the aircraft, the wings break at the root.

A read of the RV-8 double fatality NTSB report reveals both wing spars broke mid-span i.e. outside the tanks.

Max Aeros Weight 1550lbs, actual AuW 1639lbs. Max RV-8 Fuel 252lbs. Not specified in report, but I would guess if you discounted the fuel on board, it is likely ZFW was "approx" Max Aeros Weight.

(RV-4, RV-8 and others have "similar" structural designs).

I am not saying you cannot discount fuel - it is a "grey" area to some... but I would not ;)

The Australian RV-4 accident report also worth a read.
 
A decade ago I was riding in the back of an RV4 fairly often. Upside down on nearly every flight at least once. Rolls, loops, snap rolls and every combination therein. I was approximately 185lb, pilot was about the same. We often had full fuel.

I am by no means an aerobatic expert. In fact, calling me a rookie would be complimentary. But, like everything in an aircraft, one must use a bit of common sense (which I will concede isn't as common in pilots as could be hoped). Did he ever go out and pull the aircrafts max G? No he did not. Gentleman acrobatics, nice and easy. If an airliner can be induced to roll without pulling the wings off....I suspect an RV4 with a passenger wont be a problem for a pilot with some skills. The gent in the front seat was easily up to the task and he kept me from doing anything stupid in the back.

I certainly wouldn't go out and learn aerobatics in an RV4 with a passenger (unless I was learning as the passenger perhaps), but I've been in an RV4 with a 360/CS doing aerobatics and I'm still here. Of course, we each must decide for ourselves where our limits lie.
 
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Pure physics would state this might have some validity if, when you overstress the aircraft, the wings break at the root.

A read of the RV-8 double fatality NTSB report reveals both wing spars broke mid-span i.e. outside the tanks.

Max Aeros Weight 1550lbs, actual AuW 1639lbs. Max RV-8 Fuel 252lbs. Not specified in report, but I would guess if you discounted the fuel on board, it is likely ZFW was "approx" Max Aeros Weight.

(RV-4, RV-8 and others have "similar" structural designs).

I am not saying you cannot discount fuel - it is a "grey" area to some... but I would not ;)

The Australian RV-4 accident report also worth a read.
That RV-8 pulled 9+Gs, I would say prudence and common sense got lost that day, the -8 spar is also different now and also different then an RV-4. Prudence and common sense is code for gentleman aerobatics.
 
A decade ago I was riding in the back of an RV4 fairly often. Upside down on nearly every flight at least once. Rolls, loops, snap rolls and every combination therein. I was approximately 185lb, pilot was about the same. We often had full fuel.

I am by no means an aerobatic expert. In fact, calling me a rookie would be complimentary. But, like everything in an aircraft, one must use a bit of common sense (which I will concede isn't as common in pilots as could be hoped). Did he ever go out and pull the aircrafts max G? No he did not. Gentleman acrobatics, nice and easy. If an airliner can be induced to roll without pulling the wings off....I suspect an RV4 with a passenger wont be a problem for a pilot with some skills. The gent in the front seat was easily up to the task and he kept me from doing anything stupid in the back.

I certainly wouldn't go out and learn aerobatics in an RV4 with a passenger (unless I was learning as the passenger perhaps), but I've been in an RV4 with a 360/CS doing aerobatics and I'm still here. Of course, we each must decide for ourselves where our limits lie.
Your experience is the same as mine both from the front seat and the rear seat of my RV-4.
 
Great discussion here... thank you for the feedback. I am torn between the -4 or the -3 right now.

My wife is moving down to Florida this year to go back to school and we live in Georgia so I'm looking for cheap and fast transportation down there every weekend. I've run the numbers and fuel costs will be quite similar between making a 6hr drive in the car and a 2hr flight in the RV so it's a no-brainer for me. Plus I can keep the aircraft on base for really cheap.

She will occasionally and I mean very occasionally fly with me down to the Keys and places like that in FL, but the only other time I will have passengers is when a friend wants to go up for some aerobatics. Honestly if it's already cutting it close as it is I'm starting to lean towards the -3 to save some money.
 
I know I'm new.....

so I may be missing something.

My 4 weighs 1035 empty, she has an old CS prop and so is a bit heavy. I weigh 200 for a sub-total of 1235.

My aerobatic gross is 1375 - 1235 = 140 lbs.

My favourite passenger is also 120 lbs (with whom I have never done aerobatics), which leaves 20lbs fuel or about 3.5 gallons, roughly the vfr minimum.

So, by my calculations, I can strap both of us in and start the engine but not take off as I won't have my 30 mins vfr fuel.

I am in the process of certifying my plane for aerobatics and read the Austrailian accident investigation as part of my homework. The lesson seemed clear to me.
 
so I may be missing something.

My 4 weighs 1035 empty, she has an old CS prop and so is a bit heavy. I weigh 200 for a sub-total of 1235.

My aerobatic gross is 1375 - 1235 = 140 lbs.

My favourite passenger is also 120 lbs (with whom I have never done aerobatics), which leaves 20lbs fuel or about 3.5 gallons, roughly the vfr minimum.

So, by my calculations, I can strap both of us in and start the engine but not take off as I won't have my 30 mins vfr fuel.

I am in the process of certifying my plane for aerobatics and read the Austrailian accident investigation as part of my homework. The lesson seemed clear to me.

I don't know the Australian rules, but for the US folks following along, don't forget to add two parachutes at about 20 lbs each..... ;)

I've done this math for our -8 and our -6....which is why I essentially never fly aerobatics with passengers.
 
rv-4 acro with a pax

The folks who are discouraging acro with a passenger in the -4 ( especially if it puts the cg at the back of the envelope) know what they are talking about. It is not really a two seat aerobatic aircraft and if you end up spinning out of a botched maneuver it might end up in a bad way.

Chris M
 
The folks who are discouraging acro with a passenger in the -4 ( especially if it puts the cg at the back of the envelope) know what they are talking about. It is not really a two seat aerobatic aircraft and if you end up spinning out of a botched maneuver it might end up in a bad way.

Chris M

Yes but the people that have done it are not necessarily stupid either, I have done quite a bit of it myself and agree I would not do it near the aft limit, that would not be good judgment or prudent, for anyone that has flown an RV-4 at the aft limit (I have) they would or should recognize it would not be wise to do any acro, run the numbers, know what your skill level is and feel what the airplane is telling you in flight, if any of these don?t look/feel right then pass on the acro, it?s still a great ride right side up.
 
Hi Russ

That RV-8 pulled 9+Gs, I would say prudence and common sense got lost that day, the -8 spar is also different now and also different then an RV-4. Prudence and common sense is code for gentleman aerobatics.
The 8 spar was altered only in a minor way, and is substantially same design as 3/4/6/7.

My post was not directed at whether RV-4 aeros 2 up is good / legal. It was purely directed at the idea of discounting wing fuel for aeros weight purposes.

Are you suggesting the RV-8 change, and the RV-4 wing differences, are such that pulling excess 'g' with full fuel will still see the wings fold at the root and not mid-span?
 
Dan, there are aerobatics and "Gentleman" aerobatics, as you well know.

The gross weights are listed to save the spar/wing. I have and you can do gentleman rolls...little or no extra G's, with a passenger...no loops because then things can get dicey quickly.....and no demos of fighter tactics either. To a non-flyer or a pilot with no aerobatic skills, a simple aileron roll is a real treat and safe too.

Let common sense prevail and you'll be fine.

Best,
 
One more (personal) data point:

My -4 is an early model, kit 126 completed in 1983 that weighs in at 1020# with inverted fuel/oil. While little has changed overall, the last W&B was over 20 years ago so I expect that number to be slightly off, maybe +10/-10#. She'll be getting a new W&B at CI this month.

Onto the point--I've run the numbers and with full fuel and a 180# pilot [me], I'm slightly over the aerobatic gross of 1375. Since I currently don't own a 'chute and the front is only a 3-pt harness, I personally refuse to do sustained inverted and anything over 3g. Even still, I've had plenty of fun getting to know the plane, building skill, and growing confidence in it's build during this past year.

If I had a 100# passenger in the back, I'd be fine doing 2G maneuvers; steep turns, aileron rolls, mock dog-fighting sort of stuff. If I had a typical 180# passenger, nothing more than an aileron roll and some easy wing overs.

The numbers by Vans are clear. I'm willing to push them to a finite point based on my ability, confidence in the airframe, and experience others have noted here and in the past. In all reality, I'm most concerned about CG & gross weight at landing since typical passengers don't have the lust for aerobatics that I do.
 
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Hi Russ

The 8 spar was altered only in a minor way, and is substantially same design as 3/4/6/7.

My post was not directed at whether RV-4 aeros 2 up is good / legal. It was purely directed at the idea of discounting wing fuel for aeros weight purposes.

Are you suggesting the RV-8 change, and the RV-4 wing differences, are such that pulling excess 'g' with full fuel will still see the wings fold at the root and not mid-span?
Cant say, aerobatics to me is not excess Gs, all my acro is done well within the gross weight G limit, not interested in going out and pulling 6 Gs by my self or with a GIB, I can get it all done at 2.5 Gs 3 max. Good Judgment combined with skill.

If someones idea of two up acro is pulling 6 Gs or their skill level requires that or more to bail out of a mistake then this is the wrong airplane.
 
A great point

about the parachute, which I do wear for aerobatics....with my helmet, another five pounds.....
 
Go Solo...

I'm interested in purchasing an RV-4. It will primarily be used for fast economical x-country transportation, but occasionally I'd like to take some friends up to do some aerobatics.

Is that even possible? I'm 200lbs so is it possible to perform aerobatics with a rear passenger and if so what kind of weight will that person be limited to and what kind of fuel load will I be limited to?

Thanks!

I built my 4 back in 89' and flew it for 15 years while flying the F16 as a day job. Since mine was light (920 lbs) and a wood prop, aft CG limits were easily attained. I set my max pax weight at 180 lbs and no dual aerobatics, period. Back in the day Van posted all the RV fatal crashes in the RV8R newsletter. The only RV4 crashes I remember reading were all the same two causes, low fly-by's and dual aerobatics, spin into terra firma. Consider the RV4 a solo acro airplane you can give girls and kids a ride in occasionally.

My dos centavos...

V/R
Smokey
 
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Smokey, you never cease to amaze me with your knowledge of this plane. Do you by chance have those articles still? Those newsletters with the fatal RV-4 crashes seem like they would have some good lessons learned.
 
Smokey,

Ditto with hthe interest in the articles on the crash. Especially interested in any loss of control articles in the 4. I have had my 4 for under two years and 200hours in her, still lots of room to learn.

Especially interested in your thoughts on 2 up spins.

From Afghanistan,

Paul
 
Smokey

Thats very good advice from Smokey! My rear seat passenger limit is similar to his. The aeroplane is far more pitch sensitive with 180 lbs in the back seat

I can keep inside Vans aerobatic limits with me, my wife and 10 gallons each side. However, I doubt I would ever do aeros with her, as Smokey says aero solo and give the pretty lady the occasional ride.

Life is short, I want as much time flying as I can before I grow my own wings.

You can't squeeze a quart out of a pint pot!!
 
RV-4 Aerobatics

Have owned an RV-4 for some years now and I will ditto what Paul & Smokey said. Do not do aerobatics in a -4 with a passenger, PERIOD. Can you get away with it most of the time- probably. But you need to do a risk assessment and decide if the few minutes of fun are worth the alternative of an early entry to the pearly gates (or somehere else depending how wild you are).

"Gentleman" aerobatics are not the same as rolling maneuvers. You can do aileron and barrel rolls all day long with a passenger. Due to weight and/or CG issues (depending on your specific engine/prop combo) it is just not prudent to subject youurself or your passenger to the inherent risk of dual aerobatics in an airplane not designed for it.

We like our RV community and would like to see your smiling face at future events. Do not take this advice lightly.

Oly
 
Have owned an RV-4 for some years now and I will ditto what Paul & Smokey said. Do not do aerobatics in a -4 with a passenger, PERIOD. Can you get away with it most of the time- probably. But you need to do a risk assessment and decide if the few minutes of fun are worth the alternative of an early entry to the pearly gates (or somehere else depending how wild you are).

"Gentleman" aerobatics are not the same as rolling maneuvers. You can do aileron and barrel rolls all day long with a passenger. Due to weight and/or CG issues (depending on your specific engine/prop combo) it is just not prudent to subject youurself or your passenger to the inherent risk of dual aerobatics in an airplane not designed for it.

We like our RV community and would like to see your smiling face at future events. Do not take this advice lightly.

Oly
Rolls of any sort are aerobatics and yes many are very gentlemanly.
 
In that accident investigation link, they cited an aerobatic gross weight restriction as well as a tighter CG range. My POH doesn't specify the different aft CG restriction but has the same 67.36 aft limit. Is this something you guys have?

In the article, the CG limit is 1660mm (65.35 inches) as the aerobatic CG and 1711mm (67.36 inches) for normal ops.

https://www.atsb.gov.au/media/24397/aair200701033_001.pdf

The tighter CG range makes sense I guess but this is the first I've seen. I'm an RV neophyte with just over a 100hrs so hoping you guys know. After reading the report though, it's clear that this plane was over gross (even normal ops) and outside of the normal CG range as well.
 
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One of the replies mentioned snap rolls.....

How many of you do snaps in the -4?? Anyone ever ask Van's if the tail is designed for that? Aerobatic certification G limits are about the vertical axis as far as I know. Side loads and twisting loads induced from the entry can be pretty strong on the tail and motor mounts.

I'm pretty sure that is why the metal prop on an S-2B is now life limited - they finally did some calculations and testing on loads induced through snaps and gyro maneuvers.....
 
If I remember correctly Van has always said, "No snap-rolls or tail-slides."
 
One of the replies mentioned snap rolls.....

How many of you do snaps in the -4?? Anyone ever ask Van's if the tail is designed for that? Aerobatic certification G limits are about the vertical axis as far as I know. Side loads and twisting loads induced from the entry can be pretty strong on the tail and motor mounts.

I'm pretty sure that is why the metal prop on an S-2B is now life limited - they finally did some calculations and testing on loads induced through snaps and gyro maneuvers.....

If I still had an RV, I would limit snaps to very low speed as in snaps on top of a loop (Avalanche). Those are fun. These are sub-100mph snaps. Should not hurt the airplane. Van has written about entry speeds and characteristics of snaps in RVs, so he has done them. If Vans makes a general recommendation against snaps, that is probably a good one, since it's a maneuver for which pilots can put undue stress on the airplane if their airspeed is too high, or technique rough/incorrect. Snaps seem to be a very misunderstood maneuver for pilots who have not studied or had quality training on them. This translates to very rough technique and poor results.
 
Maneuvering Flight

There is a fairly extensive discussion of maneuvering flight as applies to RV's in Part 3 of the transition training syllabus beginning on page 279 of draft 1.7. A link is posted in the safety section. G-available vs g-allowable, symmetric vs asymmetric control application and computing maneuvering speeds are discussed.

In an effort to improve the draft, I would appreciate any feedback or critique in the discussion on the safety thread.

Fly safe,

Vac
 
Warner Robins

Great discussion here... thank you for the feedback. I am torn between the -4 or the -3 right now.

My wife is moving down to Florida this year to go back to school and we live in Georgia so I'm looking for cheap and fast transportation down there every weekend.

Hey Dan,
I see you are in Warner Robins as well. Not sure if you have looked up any local RV guys but I'd be glad to introduce you to several. Is it safe to assume you fly JSTARS? If you get a chance look me up and give me a call or PM me. I'm in the global. Always good to meet a fellow RVer :)
 
Hammerheads

Can one safely do hammerheads with a -4? This includes bailing out of a failed hammerhead by cornering the controls.

No passenger...


thanks
 
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Not with a passenger. If you were to enter a spin you'd likely not get out if you had someone of average size in the back.
 
Can one safely do hammerheads with a -4? This includes bailing out of a failed hammerhead by cornering the controls.

Definitely. Though with proper aerobatic training, you should not need to think about having to bail out of an inadvertent hammerslide. Being able to recover a possible inverted hammerspin is another matter. Aerobatic spin training is important. A VAF'er once described accidentally entering an inverted spin from a botched hammerhead. But you would find it very difficult to actually do a tailslide long enough to hurt the airplane during a botched hammerhead attempt. Even if you kick way late, having full power and rudder in will flop the nose back toward the ground fairly quickly before you can get a whole lot of reverse airflow. That being said, you should be careful to avoid a significant tailslide in an RV. But with hammers, most people have the opposite problem - kicking way too early and flying over the top rather than kicking too late. Taping a piece of yarn to the trailing edge of the wingtip is one way to avoid letting the airplane slide backward any. Don't let the yarn go limp.
 
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Plausible but....

I'm interested in purchasing an RV-4. It will primarily be used for fast economical x-country transportation, but occasionally I'd like to take some friends up to do some aerobatics.

Is that even possible? I'm 200lbs so is it possible to perform aerobatics with a rear passenger and if so what kind of weight will that person be limited to and what kind of fuel load will I be limited to?

Thanks!

Hi Dan, short answer, yes. Hammerheads in the 4 are straightforward but my engine routinely quit on a properly performed HH. (Most RV4s aren't inverted fuel/oil) As a Viper dude, I was conscious of G loading in my 4 as well, 3.5 will do all the acro you need to do. I did all my acro solo, aft G loading, as I mentioned previously is critical depending on engine/prop.

The RV4 is a great compromise "sport plane", small, light very clean machine optimized for guys around 5"10" and 170 lbs. your size would be better off in an 8 or something else (one design, Skybolt etc)

I performed acro regularly in the 1800 hours I put on mine. I also competed in the sportsman several times, with a carb and no flop tube. Doable as well but as Eric related, you might reconsider an RV4.

V/R
Smokey

PS: I built my 4 at Misawa back in the late 80"s. Finished it was light and nimble,
and is still flying at 2500 hours, owned by a Hornet Driver.
 
Aerobatics Entry Speed in a -4

Smokey and all

Does anyone know where I can get the recommended aerobatics entry speed and G loads for a -4?

I remember seeing them but I can't locate them.

I just completed the 10 hrs aerobatics course at WingOver in Leesburg , putting emphasis on the maneuvers that can be done in an RV and I wanna start doing gentleman aerobatic in my -4 the right way.

If anyone is looking at taking a good aerobatic course,I also highly recommend Steve Wolf and his wife Kathy Hirst, they are highly qualified and a dream to work with.

Thanks for the info

Bruno
[email protected]
 
Bruno,

Take a look at Part 3 of the transition training syllabus. The link is posted in the safety section. Basic acro is covered in the aircraft handling section at the end of the document. There is quite a bit of info regarding maneuvering flight. Drop a line if you have any questions or you want a copy of the draft in PDF format.

Cheers,

Vac
 
Does anyone know where I can get the recommended aerobatics entry speed and G loads for a -4?

Read all that you can find, but don't concern yourself too much with entry speeds. There is a very wide range of speeds that work for RVs and there's no magic to the speed you select. Folks starting out are often concerned with entry speeds. About the only entry speed aerobatic pilots really need to concern themselves with for any individual aircraft type is max. snap speed, which can hurt the airplane if exceeded. Other than that, we're simply talking about combinations of loops and rolls...and hammers. You can easily do looping maneuvers in an RV anywhere between 100 mph and Vne. Rolls can be done quite a bit slower. RVs are also stressed to +6/-3G, so you can pull anywhere within those limits that you like. You can do a loop at 2G or 6G. Most gentle RV acro is done in the 3.5-4G range. No need for more than that. One nice thing about RVs is that you don't need to dive for speed for any basic maneuver. Cruise flight speed works for any basic figure. Now if you're trying to do a 4-point vertical roll, then entry speed and G pull becomes more important. :)
 
Entry Speed

Thank you guys for the info,

Mike:I'll try to locate the Transition Training manual..

Hans: Thank you for the video, that is what I have in mind for an aerobatic sequence...Gentleman stuff..

Bruno
 
RV-4 acro

The entry speed for an Immelmann is critical. You cannot enter this maneuver at anything close to normal cruise speed and complete it safely. I think that Van specifies an entry speed of 90 to 110 mph IAS for the RV-8. Please be careful if you haven't had aerobatic training...
 
I've been reading this thread with much interest. You guys might have just saved me so to speak. I have been looking for a while now for a 4 but have decided on an 8 for various reasons. I'm 220lbs (for you Yanks) & 6ft so the 4 might be rather limiting in many ways. So a conventional U/C 8 it is:)
Was a great read, thanks to those who know best
 
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