J

JCN247DE

Well Known Member
Hi group,

I wanted to relate my recent 1st adventure into acro with my -7A. I just pulled through 20 hours on my way to completing the 40 test phase and to say that the plane has been fun to this point.... well, that would be a gross understatement.

(Disclaimer = get some aerobatic training if you are going to try this, blah, blah, yadda, gack!)

Anyway, I worked up the nerve to double check my spar and emp bolt torques with some basic aerobatics recently. My hangar neighbor was kind enough to loan me his para-seat chute for the adventure (my canopy is a tip up and I did not install the quick jettison feature... do I think I am man enough to open the canopy and get out if I were plummeting towards earth without a wing? = NO!) the chute looks cool though.

I climbed to 9.5k and began with a few stalls and then progressed to a few turn to final stalls with a bank of 30 degrees. The plane has no bad habits here and it tells you, "hey, I'm going to stall! hear the boundary air separating... want a little stick shake? get ready!" Stalls in this airplane are great. It was time to spin it.

I have enough acro hours in a citabria and decathalon to be dangerous and I am comfortable with g and being upside down. My main concern with the RV was how fast the speed would build on the downline of any stunt. My set-up is O-360 with a hartzell prop and I only have my gear leg fairings on right now (no wheel pants yet). I would love to hear from folks who are flying fixed pitch with all of the fairings on to compare notes on down line speed build up here.

Ok, enter the stall at idle, ease the stick back, when it breaks push and hold the rudder to the side that favors the lower wing and let it wind up. 1st half rev is very docile, 2nd part of the rev is quite a bit more energetic. Opposite rudder stick forward and then pull out of it. The large rudder stops the rotation instantly. I did spins to both sides and to 1.5 revs. I don't see a reason to go farther than 1.5 and the rev speed really starts to get your attention at this point.

Aileron rolls are so smooth in these things that if you closed your eyes, you would not know you did one. Pitch up to 20 - 30 degrees at speed (I was using 140ias) push the stick smoothly 3/4 to the side with no elevator / rudder input and around you go. 4 pt rolls are just as easy if you take the stick to neutral at 90-180-270- it stops right there (just have the nose up as you enter the roll and you will not lose altitude during). Don't enter a roll from level attitude. You end up pointed 30 degrees down and the speed climbs fast with throttle in.

Spilt S's are a non event and this is where I wanted to see how the down line speed would be. Slow to idle and at 75ias roll inverted and pull back down through the back side smoothly. The prop really has a nice braking effect here and the speed is very managable. For some reason I thought that I would have like 2.5 seconds before the ASI would be screaming through Vne but it just isn't the case. Don't get me wrong the speed builds quickly but just not like I thought it would at idle.

Loops are a blast in the tip up as the visibility is amazing. At 180 ias ease in a 3g pull up to vertical, over the top, throttle all the way back, pull back down the back side, pull out at 3g's (the dynon is nice for this as the g's are displayed right in your line of sight. I haven't managed to fly through my prop wash yet at the bottom. It'll come.

What a blast. I still can't believe we build these things in garages (er uh... shops) and can legally have this much fun! Rivet on....

Jeff - N247DE @ 16G (my 401k and kids college funds are going to Air BP for fuel)
 
Aerobatics are like Juggling

Jeff,

I can juggle 3 balls/bean bags...everyone always asks for four. My juggler friend can do 7...everyone always asks him for eight (which is apparently near impossible).

Soooooo, sorry for what's coming: Will it hammerhead?

I'm new to building a -7 but currently own a Bellanca Decathalon. I'm building partly because I want a go-fast airplane, but it'd sure be nice if it did all the aerobatics I like to fly in my Decathalon.

I pretty much keep to positive-g stuff even though I've got inverted systems: loops, rolls, spins, immelman's, split-s's, cuban 8's, hammerheads, and snap rolls.

I can give up the snap rolls if I have to, but I really like hammerheads and haven't yet heard of anyone flying them in a -7. I can't imagine they'd be a problem as they are a very low stress manuever, but I thought I'd ask. The authority of the rudder is probably the biggest issue.

Anyway, excellent write up on you're test flight, congratulations and keep it coming, and don't think just 'cuz I asked about hammerheads I wasn't totally jealous to read about all the other manuevers you've already done.

George
RV7 Empennage in Box in Tucson
 
Acro fun...

greylingr said:
Hi Jeff,

Thanks for the write-up, reading this keeps me pounding the rivets.

Rudi
Click to expand...

Thanks Rudi - Your comment is the reason why I wrote up my experience. If I wouldn't have read about Dan's escapades and drove my wife nuts by showing her his in-flight videos every day... it would have been a lot harder to keep the momentum building. Just trying to share the love.

George - I haven't done a hammer head yet in an RV. I'll give it a try soon though and keep you posted.

Jeff
 
dan said:
The -7 is capable of doing nice hammerheads. You will need an inverted oil system to do it properly.

)_( Dan
RV-7 N714D (683 hours)
http://www.rvproject.com
Click to expand...

Why Dan? Not disagreeing, just trying to figure out why. I would not have thought the Oil Pres would drop that fast (below 55 PSI) at 90 deg.

Larry
 
bird avoidance

rtl_flyer said:
Jeff,

Envious ? we are not allowed to aerobat the 6 or 7 in the UK.

Sounds great,

Tim.
Click to expand...

Tim,

Loops, rolls, spins and the like can all be used to avoid pesky high flying flocks of birds that don't show up on radar! Considering that you as PIC of your aircraft must "see and avoid" such hazards in the air you may have to take full advantage of the spunkiness of these aircraft...

If it is not the annoying birds that one must aggressively avoid in the air then sometimes it's the deer that must be "shooed away" from the runway before landing with a few low level high speed passes.

Watch those animals!
 
rtl_flyer said:
Envious ? we are not allowed to aerobat the 6 or 7 in the UK.
Click to expand...

Now THAT must be a difficult temptation to resist.

You could always just install some extended range tanks and don your life vests. We'll leave the light on for you. :)
 
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Jamie said:
Now THAT must be a difficult temptation to resist.

You could always just install some extended range tanks and don your life vests. We'll leave the light on for you. :)
Click to expand...

Jamie,

Off subject slightly. I met an RV6 owner in France (with N reg), he started building in France, his company moved him to America. He finished his kit, they moved him back to France. So he fitted tip tanks and a big tank in the passenger area, and flew it back to France!! Brave or mad??
Would love to fly mine to America ? figure it will probably be easier than getting aerobatic clearance??.

Tim.
 
Inverted oil

lrfrey said:
Why Dan? Not disagreeing, just trying to figure out why. I would not have thought the Oil Pres would drop that fast (below 55 PSI) at 90 deg.
Click to expand...

Go ahead and give it a try and you'll see what I mean. :eek:

On the vertical line, held for any length of time, the oil is collecting back at the accessory case, and will most likely be chucked out the breather.

Then you go zero G over the top, with some funky light loading in a few different directions as the nose "yaws" in the vertical plane, and oil pressure nosedives.

That said...

If you want to stick with positive G maneuvers, it is kinda possible to perform a "hammerhead-like" maneuver that maintains positive G. It will not look good from the ground, so don't try to impress any judges. :rolleyes: But a vertical line with a reversal to a vertical down line can be done with positive G.

Be careful out there.

)_( Dan
RV-7 N714D
http://www.rvproject.com
 
Will you guys quit it !

We aren't allowed to do ANY aeros in our RV 6, 7 or 8's in the UK. Our version of the EAA want stress tests, spin tests, this test, that test and of course, Vans won't specifically recommend any of it - why should they ?

We are in a state of impasse :mad:

So, I can watch Dan's fine videos and weep, at least I have a Citabria and can still do some while we are building our 7
 
If you try a hammer-head make sure that you have quite flying before booting the nose over. I made the mistake a couple of times and was in an inverted spin faster than you can blink. Have fun and always be careful. I fly a fixed pitch 0-360. I enter a loop from cruise and don't touch the throttle at all during the entire loop. The downline speed does not build up fast nor the rpm's.
 
I have done hammerheads in my RV6. With out an inverted system, you may experience momentary engine stoppage and oil on the belly as a result of the maneuver.
You probably already know this, but...In doing the maneuver, when kicking over left rudder, you also need to put in opposite (right) aileron to counteract the tendency for the high wing to turn you over on your back. (Due to increased relative wind over the high wing and reduced wind over the low wing.) This will keep the hammerhead straight and coming back down on the same line as you went up, creating a 180 degree reversal.
Make sure you don't have any loose items in the cockpit because they could/will float around if you don't kick over before you go negative. (I would suggest you kick over while you still have forward inertia, since I'm not sure what a tail slide would do for an RV!)
As in the down side of a loop, speed can increase quickly, so be prepared.
I tend to stick with the basic positive G maneuvers, although stressed for aerobatics, I wouldn't classify the RVs as unlimited aerobatics capable.
 
Excellent thread. Makes me want to run out to the garage and drill some holes. With the shop getting colder, and the project getting more complicated (wiring, firewall fwd), I've been lacking in enthusiasm lately. I just need to fire up one of Dan's videos.
 
Aerobatics in the RV's is really fun, but please take notice of Dan C's and others comments on hammerheads. What looks like a stone simple maneuver actually isn't and can get you into some really weird situations.

Here's a couple examples...if you accidentally get past vertical on the upline (quite easy to do) then start pushing to get back to vertical at the same time you're almost out of speed, guess what...you're on your back faster than you think in an inverted spin (or at least the start of it) - because instead of pulling and causing the stall, you're pushing and causing the stall.

Also stated was the kicking over cross controlled near the top. If you don't time things right, you can and will end up in either a right side up spin or inverted spin. Don't worry, many people have fallen out of hammerheads either forwards or backwards then ended up in a spin and lived to talk about it (ask me how I know)!

Like others have said, if you have loose things in the cockpit you ought not be doing these types of wifferdills. I got smacked in the face some time ago by an errant bottle of Dr.Pepper one day that quickly got my attention!

As Dan stated, it's possible to do a "near hammerhead" or a really nice tight wingover that provides almost the same amount of fun with a lot less danger and stays at least above zero g most of the time.

I have inverted fuel/oil in my RV6, but rarely do anything that is negative....positive stuff is just so darned my fun by itself.

Last but not least, it should be re-iterated what others have stated. Don't try to teach yourself acro in an RV. They wind up in a spin pretty quick past 1.5 turns, they get going fast pretty quick when going straight down, and lastly, this thing isn't a Pitts. So, no snapping, no herky jerky stuff, just keep it simple and you'll have a blast! - oh - and remember that chute!

Cheers,
Stein.
 
If you do install an inverted oil system, mount the oil valve at an angle of 10 or 15 degrees off vertical with the bottom sticking out. That will keep your oil pressure up throughout a hammerhead, and stop the prop going fine (or coarse with an acro prop) when the oil pressure drops. You want the system in inverted mode on the up line, when all the oil rushes to the back of the crank case, to feed from the inverted pick-up (vac pad or breather pick-up), and in erect mode on the down line, feeding from the front of sump.

For Mike & Tim, go hide behind the nearest cloud - its an impossible rule to enforce.

Pete
 
Norman CYYJ said:
If you try a hammer-head make sure that you have quite flying before booting the nose over. I made the mistake a couple of times and was in an inverted spin faster than you can blink. Have fun and always be careful. I fly a fixed pitch 0-360. I enter a loop from cruise and don't touch the throttle at all during the entire loop. The downline speed does not build up fast nor the rpm's.
Click to expand...


Did you fall into the inverted spin in an RV. I'm interested for more comments on the characteristics of an RV6 or RV7 in an inverted spin. It is my understanding that many aerobatic aircraft will not remain in an inverted spin without positive control pressures. Is this the case with an RV6/7. Left to its own devices will an inverted spin become an inverted spiral dive.
 
Just wanted to expand on the aerobatics from what some people have said. A few rules I live by... I've got quite a bit of dynamic manuvering time in a few different planes.

Like someone said, if you're gonna do it, get training.

Secure everything in your cockpit before an acro flight. My recommendation would be to take EVERYTHING out. Tiny objects can find their way to catostrophic places.

On the loops... if you want to find your own wake on the bottom don't pull power on the back side. More than likely what you're flying is an oblong shape and not a true loop. Pull a steady G like you said (I'd recommend about 2.5 if you're can get an entry speed of about 170) until you're starting to crest over the top, about 120* nose up, and relax the pull. Air speed is gonna get slow... but you're relaxing the pull, and not putting any load on the wing, and lowering the AOA... the wing won't stall... as you start to come down the back side don't start your pull too soon, as airspeed starts to build pull to that 2.5 G again and hold it. Power SHOULD never come off, without and inverted oil system I don't know what to tell you. If you do it right you'll always have SOME (0.2ish at the top) positive G on it. With some practice you can time the pull on both sides to arrive at the exact same altitude you started... even if you have to dive a little for entry airspeed.

When you get comfortable with that try a squirrel cage.... consecutive loop, 1/2 cuban eight, immelman, split-s. If you get real good at it, you should be on the alt, a/s, and heading you started. Always helps to have a reference line on the ground (long road, power line slashes) something on the ground for over the top stuff.

A final note... if you get yourself nose high and freak out or panic...

If you're pure vertical (if not skip to next paragraph), give the stick a little nudge in whatever direction the nose is tracking, use the momentum to get away from bullseye nose high and then...

Neutralize the controls!... center the rudder and stick and HOLD them there.
Power to Idle...

Wait... the nose will fall through (with maybe a few occilations), and when you find yourself down hill and a/s increasing, then start your recovery.


All just acro info I've learned over the years... take it as you wish, expand upon it, etc. I've there's any questions on other manuvers such as barrel rolls, wingovers, etc... and the mechanics... ask!
 
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