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How much Acro in a -9?

G

gstopyra

Member
I know everyone has their reasons behind what RV they chose to build. I know there are some out there that built with one type of flying in mind, only to find themselves doing something totally different years later. I'm more in the mindset of not buiding a -9 then realize I would have liked to do some mild acro.

The question I'd like to open to everyone is how much yank and bank can a -9 handle? For those flying 9's...are you comfortable trying or doing anything beyond steep turns? For those not flying 9s...how many Gs are pulled in a typical 90 bank, roll, loop, etc.?

I know a -7 can do pretty much everything, but want know how much (if any) a -9 can do.

Thanks!

Greg
 
G's

gstopyra said:
For those not flying 9s...how many Gs are pulled in a typical 90 bank, roll, loop, etc.?
Click to expand...

There is a wide range on some of these things and a difference between a competition loop and a lazy old loop but here are some rough numbers (when they are done 'safely')

Roll - about 1.5-2.5G
Loop about 3-4G

These are rounded numbers for coordinated banked turns.
45 1.4G
60 2G
75 4G
80 6G

Keep in mind that doing the moves 'wrong' can have serious ramifications. Split-S'ing out of a roll is not an uncommon result when people try rolls the first time (even if they can roll the 172 on the sim), this will most certainly result in over speed/stressing your RV.

Chuck

PS You'll be burning of energy quickly with a coordinated 4G
 
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rv9 or rv9a rolls , loops , dives

I would love to hear more about these things, I am sure I will never do any of them but it would be nice to know those limits in reguards to vans g ratings..


even if its not allowed what have some of yall tried so far in a 9 or 9a..


Danny..
 
The RV-9 is not an aerobatic airplane in any configuration! PERIOD. And your Operating Limitations will prohibit aerobatics.
Mel...DAR
 
I understand that the -9 will do a Lomcevak. But just one. ;) :eek:

I'm disappointed in talk not only about the -9 doing ANY aerobatics, but even about the -7 doing advanced aerobatics.
It may not be long before someone hurts themselves (if you know what I mean) and gives the RV a bad rap for forcing it to do things that Van never designed nor intended it to do.
 
banking turns

thanks guys, I knew the 9 was not acro, I just don't know what constitutes
acro, how much of a bank turn is considered acro, 30 degree's or is going upside down ie: a roll acro ? , I don't know enough about any of this.. as far as I know 30 degree's is pushing the limits of a 9.. I don't see any info anywhere on that.. I don't think vans site shows any g rating on the 9 or 9a
I thought I read something that said plus 6, and neg 3 or something like that
but I can't find it anywhere, even if that was just hitting some bumpy air it would be good to know the wings won't fall off.. I don't have any ideas of
flying acro, or I would have built the 7a instead, I just would like to know
the airplane is stronger than straight and level flight, even if it never sees
rought air..

Thanks..
I only asked because I am learning, not planning on hurting myself..
otherwise I would have bought a gyro :) or skydiving.. I don't want to do
either.. can't imagine how that guy felt at swfi that crashed on a test
ride in that gyro, I don't think he will be buying one of those..
Danny..
 
90 degree bank in a 9

While on my demo ride in the 9A, I ask if the plane could do 90 degree banks and how many G's would it be. The answer I was given was that the G's would be infinate if altitude was maintained. My pilot proceded to do two 90 degree banks as we returned to the airport. One to the left then on to the right. We lost about 2000 ft real quick and I don't think that we were at more then 2 G's at any time.

This is what convinced me that the 9A was exciting enough for me.

Kent
 
kentb said:
While on my demo ride in the 9A, I ask if the plane could do 90 degree banks and how many G's would it be. The answer I was given was that the G's would be infinate if altitude was maintained. My pilot proceded to do two 90 degree banks as we returned to the airport. One to the left then on to the right. We lost about 2000 ft real quick and I don't think that we were at more then 2 G's at any time.
Click to expand...

If you were to maintain a coordinated 90 degree bank and maintain altitude the G's would be infinity (i.e. there is no component of lift pointing up), but of course that's not how you would fly it. You would fly it uncoordinated with lots of rudder trying to point your nose up, but that's a different story.

As another poster mentioned a 9 is not made for acro, don't waste your time (or your hide) messing with it.

Chuck
 
FAR 91.303 defines aerobatics as any intentional maneuver involving an abrupt change in attitude, an abnormal attitude, or abnormal acceleration not necessary for normal flight. 91.305 (parachute requirements) goes on to describe any intentional maneuver that exceeds a bank angle of 60 degrees relative to the horizon, or a nose-up or nose-down attitude of 30 degrees relative to the horizon.
Mel...DAR
 
Godspeed,
I have the same question- trying to decide between a 7 and 9.

I do take some exception with your comment: "not planning on hurting myself.. otherwise I would have bought a gyro"

The current crop of centerline thrust gyroplane designs are exceptionally fun, safe, and stable (with training) with or WITHOUT power. Far more so than any fixedwing. :confused: If you think a 90 degree turn is exciting in a RV7, try them in a gyroplane sometime.

If not for high density altitude problems here, I would have gone gyro over fixed for the cheap seat-of-the-pants flying excitement. :D
 
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Thanks for the answers

I appreciate everyone's feedback. I think MEL pretty much gave me the answer I was looking for. While airplanes can DO many manuevers they're not intended for (Tex Johnson and the dash 80 prototype roll), they are prohibited for a reason. Sure, there is a safety factor designed into the airframe, however, that is there for an extra margin should you encounter turbulence in flight or something else unexpected. I don't want to willingly push that limit just for some fun.

So that's settled for me...

RV-9 if you just want to fly without exceding 60 degree bank
RV-7 if you want to do some acro (non-competition)

:eek: I appologize if this gave people the idea or the impression of some newbie wanting to put his life and reputation of a great brand at risk. I'm just trying to get the low down of what the limits are of each model. :)

Thanks again...

Greg
 
more thoughts

Not that I would want anyone to be unsafe, but as far as regulations for expermental aircraft goes. The RV 7 - 9 acro designation is just Vans recommendation. How we register our planes is up to the us the builder. Keep in mind that what ever you claim your plane is capable of doing (acro or grouse weight or ...) you need to preform test during your phase I fly off.

I for one will not register my 9A for acro.

Kent
 
just normal conversation

I was not trying to affend about the gyro, "I am sorry" I was just joining in the thread to learn something, I guess I am not taking life serious enough I suppose, I was just wondering if anyone pushed the limits a little on a 9 or 9a, and I really have no idea what those are, thanks Mel, I have never read the FAR on acro mostly because I don't plan on doing any.. can't we lighten up a little and enjoy some fun conversation without everyone getting affended, stressed or mad ? My new corvette goes 175 mph but you don't see me driving it that fast either.. my porsche 911 goes 160, same thing.. I can follow the rules or I wouldn't be building , have some fun everyone..
 
No offense taken at all- I just did not want to misinform anyone.

Gyro safety has improved greatly in the last 2-3 years through geometric design improvements. My guess is that a lot of newcommers will gravitate to gyros through the Sport Pilot program in the next few years. Gyroplanes are ideal for a person who desires risk free, low cost, low-speed, local flying; they will eventually grow into higher performance aircraft.
 
Yeah, pretty much provided the pilot is trained. I suppose one is always exposed to getting hit by something else in the air or something can break though, so risk free is probably a little overstated, but it is as near to risk free as one can get in aviation.

A CLT gyro cannot bunt over or enter PIO's like the old designs could, the cause of most of past accidents. A loss of power results in a gentile autorotation into a landing flare under full control. The new landing gear designs can fully absorb a hard (~3G+) landing.
 
rv9a g limits

Here is the manual limits, so its good to know what = 4.4 means, I didn't what degree bank or turn pulled what G rating.. thanks guys this is a great learning thread.. I am sure it will help others too..

Danny..


Section 15 in the manual has the aerobatic
> information on the
> planes. The -9/9A is stressed to +4.4, -1.8Gs. See
> page 15-20.
 
RV9 acro

Guys, ALL airplanes are capable of aerobatics...Lear jets and Citations have been rolled and Bob Hoover does/did an incredible job with the non-aerobatic Shrike.
A Cessna 150 is also rated at 4.4+ and 1.8- G's.and have been rolled. looped and spun! Aerobatic only means, according to the beaurocrats, pitch over 30 deg and bank over 60 deg....what a crock. An ag-pilot puts on a show with a stock Grumman Ag-Cat biplane. My boss rolled a Cessna 210 on the way home from a $100 lunch many times.

Acro or aerobatics is in the hands of the pilot.NOT the rating on the airplane. I'm probably gonna catch crap for this post, but I'm in the ag business and have rolled and looped Cessna Agwagons and my Airtractor 301 with 1340 Pratt and Whitney. Unfortunately, most pilots are incapable of performing competent, low g aerobatics, not the airplanes. There are many, many aerobatics performed in "non-aerobatic" airplanes. A Piper Cub wasn't 'designed' for aerobatics but have been snap-rolled, looped and spun.....in the hands of A CAPABLE pilot....there's the rub....capable.
Pierre
 
"Aerobatic only means, according to the beaurocrats, pitch over 30 deg and bank over 60 deg....what a crock."


Actually, No. This only defines the requirements for parachutes for non-essential crew members.

? 91.303 Aerobatic flight.
No person may operate an aircraft in aerobatic flight?

(a) Over any congested area of a city, town, or settlement;

(b) Over an open air assembly of persons;

(c) Within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport;

(d) Within 4 nautical miles of the center line of any Federal airway;

(e) Below an altitude of 1,500 feet above the surface; or

(f) When flight visibility is less than 3 statute miles.

For the purposes of this section, aerobatic flight means an intentional maneuver involving an abrupt change in an aircraft's attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight.

If I believe an instructor I had many years ago (who threatened to beat me about the head and shoulders if I didn't quit "horsing" the controls) I was actually performing aerobatics!
 
For those who care, the g in a coordinated constant altitude turn is equal to 1/cosine(bank angle). Regarding acro in a 9 (or anything else), I think the issue isn't whether you can do acro in it, it's whether you should. Botched manuevers can produce lots of g quickly and it's nice to have a large margin of error. Incidently, the g-ratings for these and other planes are for loads distributed uniformly and in the vertical direction. Acro puts twisting and less predictable loads on the structure as well. The bottom line is that planes do sometimes break and it has happened to RV's as well. If you want to do acro, why not get a plane that was designed for it?

Steve Zicree
 
Asymmetric G loadings

A note from the peanut gallery (ed: as already stated by szicree): Keep in mind that all of the G ratings given to aircraft are in one axis (i.e. pulling straight back). If you apply assymetric loads (i.e. roll and pull), those loads are irrelevant and your limits are substantially less than published. Don't believe me, just ask the T-34 combat simulation schools. :( Fly safe.
 
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more about acro

Steve...well stated.

a similarly related thread from airliners.net talks about the Roll Tex Johnson did in the 707 prototype.

http://www.airliners.net/discussions/general_aviation/read.main/2122750/

I specifically want to point out a post about halfway down:

"There were also those two guys that tried a barrel roll with a Beech 99 and only succeeded in digging a smoking hole into the ground...

Link to the ASN report: http://aviation-safety.net/database/record.php?id=19930428-0

Link to CVR transcript: http://www.tailstrike.com/280493.htm "

Pilot cabability is the key. If you think you're skilled enough, and are willing to risk your life that you can perform a manuever and stay within the limit's of a 9... that's you're hide. Just remember (as evident by the DC airspace incursions) it only takes 1 or 2 bad apples to spoil the bunch...and the rest of US would feel the loss. I sincerly hope that most pilots out there err more on the conservative side of flying. That means adhearing to what the FAA and it's inspectors certify the aircraft to perform.

Perhaps MEL can answer the question better. Could someone apply for an aerobatic certification in a plane normally not certified?

I do remember seeing the Old Reinbeck Aerodrome Airshow back in NY with a routine by the "Flying Farmer". although he doesn't do loops or rolls, he does perform a routine where he yanks and banks a cub quite a bit. He may be skilled enought to not load the airframe in those manuevers (I remember them being QUITE uncoordinated!).

I think I've beat this horse enough... My question has been answered...

(Leaning towards a -7) :)

-Greg
 
As an amateur-builder you are free to apply for anything you want. Whether or not you get it depends on your inspector. For example if you build an RV-9(A) and request operating limitations that allow aerobatics, the first thing the inspector is going to do is check to see if the designer has authorized aerobatics. If not and the builder still wants aerobatics included in his operating limitations, the inspector will ask for reasonable documentation showing that the aircraft has been modified sufficiently to allow them. The inspector CAN include aerobatics, but he likely will not unless the provided documentation convinces him otherwise. If he does indeed include aerobatics in the operating limitations and the airplane is involved in an accident involving aerobatics, the feds are going to look very closely not only at the accident but also the inspector.
I doubt very seriously that any inspector is going to authorize aerobatics in an airplane not designed for such.
Mel...DAR
 
OK, not to pick nits here, (well, maybe a few :D ), but by definition a stall is an aerobatic manuever. While I never experienced this during primary power training, during my glider training I was repeatedly instructed not to initiate any stall demonstrations during the checkride that could not be completed by at least 1500 AGL so as not to bust the "aerobatic" limitation.

While it may not require a parachute because the angles are controlled it definitely meets the criteria of intentional maneuver involving an abrupt change in an aircraft's attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight. Is the training regimen part of normal flight per the FAR's? I suspect not......

If we agree on this, then any airplane used for training would have to be certificated for aerobatic flight? Or, are you limited to only manuevers that fall within the certification, ie; Normal or Utility? Don't you just love the inherent contradictions within the regs?

Absolutely no question in my mind that the pilot's skills will make the difference. I think that even I could self-destruct in something designed for +/- 10 G's!
 
So what about the other RVs

Mel,

I'm sure I already know the answer... but I'll ask anyway.

So do the other RVs (except 9 and 10) qualify for aerobatics? or are they certified for certain manuevers?

I see your point about if something happens and the FEDS coming after the inspector if he certified something that probably shouldn't have been. Lot of responsibility with that inspector job...eh?

-Greg
 
-7 for me

I decided on the 7 for aerobatics. Was comparing the 9 and 7 before I bought. And they seemed pretty equal in performance ( on paper anyway ;) ). But knowing I want to do limited aerobatics I decided to go with the 7.
 
vans take on this

this is what I got back from vans on this subject..


Danny,

Our official statement is that the -9/9A is a
non-aerobatic plane.
With that in mind, if you have a G meter and stay
within limits,
what you do in the plane us up to you. As an aside,
the flop tube
is only needed if you are going to do
sustained inverted flight.
As
long as all maneuvers are positive Gs, no flop tube
is needed.



> <nofill>
Bruce Reynolds
[email protected]
 
The RV-3B, -4, -6, -6A, -7, -7A, -8, -8A are all consider aerobatic when built according to Van's plans and instructions. The RV-3 without the "B" wing has been removed from aerobatic approval.
Mel...DAR
 
Almost anything can be rolled or looped

Yes the Boeing 707 was rolled over lake Washington.

Bob Hoover flew a Strike Commander, medium size corporate twin doing low altitude aerobatics at air shows for years.

A Cessna C-152 can be rolled or looped and even comes in an "aerobatic" version, as does the Beech Bonanza (a regular Beech Bonanza, not a T-34, which is of course based on the Bonanza)

The question is not can a RV-9 do it, but is it safe? There are two parts, handling/control and strength. The RV-9 no doubt has the controls and maneuverability to do a loop or roll very easily. What about strength? Aircraft are designed to load factors with margin of safety. From Van's aircraft, the structure was designed for a lower load factor. Why? To save weight and tailor the plane for the mission. The RV-9s has lower Limit and Ultimate load factors (read, not as strong). I don't know what the RV9 Ult. load factor is but guess it is at least the standard FAR23 utility catagory 6.6G Ult. load factor (4.4G limit).

I can tell you a good aerobatic pilot can do basic aerobatics without pulling more than 3Gs, which is about 1/3rd of the ultimate strength (9G) or 1/2 of the (6G) limit load for other aerobatic RVs. The 3G differnce between the 9G Ult and 6G limit load factors is the margin of safety, to account for small structural and manufacture defects and variations. If the RV9 has a 6.6G ultimate strength or a 4.4G limit load factor, than you would be operating at 68% of the limit load doing 3Gs. Is that OK? Yea, but if you screw up and end up pulling 6Gs, you could be within 10% of ultimate or "failure" load. :eek: What if you pull 6.6? Wrinkled skins or worse

My concern is people who are talking about doing aerobatics in a RV-9 have no experience doing aerobatics, but you have to learn somehow. Many aerobatic pilots are self-taught, but I would not recommend it, especially in a non-aerobatic airplane that is slick and can build airspeed quickly. Plus pilots are drawn to the RV-9 for the more docile handling, so now they want to pull 3Gs and go upside down? Know thy self.

The fact is the RV-9 is not as strong as the other models. RV-9 builders talk about how great it is, but you need to accept the limitations or the pros as well as the cons of a design. Even the "strong" RV's can pull big parts off if you pull too hard. You can do 1G rolls all day, but a screw up could end up in a high speed split-S and bad news.

Cheers George
 
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And don't forget the -9 has a longer wing span, much more horizontal tail area, and a higher lift airfoil thereby creating more problems when outside the intended envelope. Bottom line; If you want to do aerobatics no matter how minor, build a -7!!!!!
Mel...DAR
 
per the mission

This has been great learning, how would a non pilot have learned all this other than asking quesitons, I was not asking someone with a flying 9 or 9a to go try some of this.. I have not intentions of doing any of it, but it would be good to know what the limits are, so I will never exceed a 40 - 50 degree bank, and this will most likely prompt me to install a g meter, I didn't plan on that because I never planned on pushing it, and still don't, a simple roll might be fun one day but I see now that its much more difficult to do a nice one that I knew, in the vans video it shows a roll that starts level flight, goes about in about 6 very smooth like 2 o'clock, 4 o'clock, 6 o'clock, 8 o'clock
10 ect.. 12 that looks like it is not stressing much of anything.. if you have seen the video ( I think its the old one) where are the stress's on that simple roll ? I am still learning so please don't get upset with the questions.. I am not going to hurt my self or my airplane intentionally.. or by trying something
that its not designed to do.. smooth level flight ,straight , rightside up,
no excessive fpm , set it on the ground as smooth as possible, (hell I worked far to hard building this thing to hurt it..) plus I have places to go and things to see.. :)


Danny..
fitting the wingscreen.. today.. (this part of the project is not my faviorite)

Thanks guys..
 
G Ratings for 9

I believe the -9 is rated for +4.4 and -1.8 at 1600lbs, if I remember the manual correctly. Don't have it in front of me right now.
 
This thread has been informative- Ive been thinking 9A mostly because of the lower stall speed. Now Im leaning 7A, not because I want to fly inverted, but because of the higher strength factor.

To those who have flown both, just how much more sensitive is the 7 over the 9, or more to the point, where will it be noticable to a new pilot? Which would be safer/better off of a grassy, rough strip (I notice the 7 has a significantly greater rate-of-climb and higher ceiling listed)?
 
Cobra, if sensitivity were an absolute condition that couldn't be adjusted to, then no one would be able to fly F-16's... ever.

Any aircraft you've never flown before is going to feel "different". I'll bet your first ride in your first GA aircraft was really strange to you and you didn't know what to expect; right? And that was probably a C150 or equivilant.

But no matter what a new aircraft's handling characteristics are, you'll very quickly become accustomed to it, and after just a few hours, you'll wonder what all the fuss was about.

Since I haven't noticed a plethora of -7's littering the landscape in tangled piles of rubble, I'm reasonably sure you'll be just fine with one of your own.
 
Danny,

The roll in the video is a six point (give or take) roll. This is a variation on what's usually called a slow roll. Such a manuever requires constantly changing rudder and elevator inputs as the plane rolls to keep the nose on a point. It looks ALOT easier than it is. For example, when the plane is at 90 degree bank you need a ton of top rudder to keep the nose up and some forward stick to keep from turning off heading. Done properly, there's very little load on the airframe.

A much easier roll to perform is an aileron roll. This is done by basically just shoving the stick all the way to one side and waiting for things to get right side up again. The catch is that the nose is dropping through the entire manuever. So if you don't get the nose up high enough before you start, you'll end up VERY fast and nose down by the time you finish. This can be disastrous, especially in a clean airframe like an RV. Done well, there's very little g here either. Screw it up, and you'll exceed 6g easily.

Finally, there's the barrel roll. This one looks like one of those "corkscrew" type roller coaster rides. It requires coordinated use of all controls, but is fairly easy to get right. It shouldn't go much beyond 2g if done right.

The point in all this is that acro can be done with very little load, but when things go haywire, the g builds up very fast. Proper training and equipment is the ticket if a guy wants to have his fun and not leave orphans behind.

Steve Zicree
 
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