Rumbling Thunder
Member
What kind of aerobatics do you guys do in your RV-8s? What are some more advanced maneuvers can you do besides simple loops and rolls?
Van's Air Force
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Aerobatics
- Thread starter Rumbling Thunder
- Start date
smithflys23
Well Known Member
Hammer heads
I’ve just started experimenting with hammer heads. Super fun with a smoke system!
All the standard stuff.....Cuban 8’s, Immelmann, Split S, Spins, slow rolls. It’s more fun when you start stringing maneuvers together, and plan them to maintain your “box”.
I’ve just started experimenting with hammer heads. Super fun with a smoke system!
All the standard stuff.....Cuban 8’s, Immelmann, Split S, Spins, slow rolls. It’s more fun when you start stringing maneuvers together, and plan them to maintain your “box”.
I certified KELLI GIRL for positive G aero maneuvers plus a couple of momentary negative G, specifically loops, aileron rolls, barrel rolls, split S, Immelmann, and half-Cuban 8.
If you build negative G oil and fuel pickups, you can expand the neg G repertoire, as long as you certify the aircraft for it in Phase 1 and write it into the POH. I'm no aerobatics expert, just the casual G-puller.
If you build negative G oil and fuel pickups, you can expand the neg G repertoire, as long as you certify the aircraft for it in Phase 1 and write it into the POH. I'm no aerobatics expert, just the casual G-puller.
ronschreck
Well Known Member
Here you go!
No tail slides and keep the Gs and weight within published limits. Have fun.
https://www.youtube.com/watch?v=gNNKnD2N5sI
No tail slides and keep the Gs and weight within published limits. Have fun.
https://www.youtube.com/watch?v=gNNKnD2N5sI
ronschreck
Well Known Member
No. Enter at 150 - 170 knots with a 3.5 - 4 G pull and you will end up at about the same speed that you entered.
There is no need to close the throttle in any airplane. Laws of physics dictate that from a constant power setting you cannot gain airspeed if your entry and exit altitudes are equal. Leave the power in. If you're blowing out the bottom too fast you're doing something wrong. Some basic acro instruction helps.
ronschreck
Well Known Member
Yes. There are a few snaps in the Intermediate level of IAC competition. The RV does snap!
Plummit
Well Known Member
Foghorn
Well Known Member
Ok I’m a complete rookie. I have done aerobatics in an Extra 300L (Upset recovery training) but would like to do them in my RV8, after getting some training. Oh I need to finish the build to but that’s a different story.
Here is my question.
Should I have a flop tube in one tank for basic aerobics (Loops, rolls, spins) or can I do all that with normal fuel pick ups? I’m not currently installing inverted oil and don’t plan to, at least for now.
Thanks
Here is my question.
Should I have a flop tube in one tank for basic aerobics (Loops, rolls, spins) or can I do all that with normal fuel pick ups? I’m not currently installing inverted oil and don’t plan to, at least for now.
Thanks
ronschreck
Well Known Member
You only need a flop tube for extended inverted flight. If you have not built your fuel tanks yet then this might be a good time to put a flop tube in one tank. It's cheap and easy. You can do the entire IAC Sportsman sequence without a flop tube but you should have inverted fuel (injection) to do figures correctly. And you will want at least a half-Raven system to keep the belly clean. For positive G maneuvers, loops, barrel rolls, spins, etc. you don't need fuel injection or inverted fuel/oil systems.
WillyEyeBall
Well Known Member
Great flying and video. I miss that.
WillyEyeBall
WillyEyeBall
Foghorn
Well Known Member
Thank you! I think I’ll start small (flop tube) and go from there. I have the SDS EFI system and will check out the half-raven.
Thanks again
Nice routine but some of that just sounds so hard on the engine. Is that you Ron? Is that an AEIO- engine? Obviously has inverted fuel and oil and I would assume and aerobatic prop?
RV8Squaz
Well Known Member
It is a Vans prohibited maneuver because the tail is not structurally designed for the loads. As for knife edge passes, pushrods are not required. The correct rudder input will put tension on the appropriate rudder cable. On my RV-8 you can hear some buffeting and wind noise on the canopy.
BTW, I don’t think either maneuver is permitted with the RV-10.
RV8Squaz
Well Known Member
It is hard on the engine, on everything in fact. It is going to be harder on the aircraft than flying at 1 g level flight. Although the airplane is designed for aerobatics, it will require more maintenance and fixing things here and there.
Flying these figures perfectly requires a lot of practice. In order to nail a 1 1/2 turn spin to within 2.5 degrees of rotation and 2.5 degrees of pitch from a perfect vertical line may require a dozen spins in one of many many practice flights. So much for shock cooling!
I’m 99% sure that an AEIO engine is an IO engine with a Christen inverted oil system.
Here’s my Sportsman Known and Free sequences from the 2018 Nationals:
https://nationals-videos-2018.s3.amazonaws.com/IAC1109.mp4
https://nationals-videos-2018.s3.amazonaws.com/IAC1130.mp4
ronschreck
Well Known Member
Yes, that's me. The engine is a narrow deck IO-360-B1E with standard compression, constant speed prop and inverted fuel and oil. The prop is not an aerobatic CS (ie: counterweighted hub) but I never found the need for that. Aerobatic routine is typically flown at full throttle, full rich and 2700 RPM. That engine went for 2250 hours and I overhauled it just because the plane was down for a cracked canopy. At overhaul the A&P was surprised at how little wear was evident. Crank, cam and case were all good.
Aerobatics are certainly harder on airplanes flown in one G flight but with proper periodic maintenance you can expect engine to go to TBO and beyond and airframes to last indefinitely.
BillL
Well Known Member
From my research . . . the crank prop flange is thicker. Not sure about anything else but that was true a few years ago.
ronschreck
Well Known Member
Perhaps you don't! I would never encourage anyone to exceed the weight or CG limitations published by VANs. You must include the weight of pilot, passenger, parachutes and all fuel. I have always done aerobatics solo.
ronschreck
Well Known Member
You see a lot of stupid things on YouTube.
gmcjetpilot
Well Known Member
So you do aerobatics with passenger. I am sure you comply with FAR's and both wear a parachute? Within W&B limits for aerobatics? Just asking. What is your gross 2 up weight. I ask because I find many RV's a little "fat" and two up with more than MIN fuel often exceeds the weight limit for aerobatics. The chute requirement is an FAR's.
Your speeds and G's are unnecessarily high from my experience. RV's can enter or exit any maneuver at 3 or 3.5G's. Your higher G's is due to higher entry speed.
170 kts? You man 170 mph? With skill and proper technique you can do aerobatics at less than 170kts and less than 4 G's.
ronschreck
Well Known Member
Wow, picking up a four year old thread. You must be bored. Anyway, I said knots and I meant knots. Yes you can do aerobatics at slower speeds. I spent ten years in IAC competition with my RV-8 up to the Intermediate level. A sequence of 10 to 12 aerobatic maneuvers in the confines of a competition box demands all the power and speed you can get from the RV. While a 3G 140 knot loop entry is manageable it may not be pretty and the low energy state at the completion of the loop may leave you with insufficient energy for the next maneuver in the sequence. I am full throttle for the entire sequence except for spin entry.
Should there be any confusion or doubt on the subject of RV aerobatics with two on board, I don't do it and caution those who do. Both must wear parachutes (FAA Requirement) and you must stay within published G, weight and balance and Vne limits.
It's impossible to make a loop round with only 200 hp if your initial pull is 3g. There isn't enough energy left when you reach vertical up to make the second quarter the same radius as the first. Increasing the entry speed just makes the first quarter loop bigger, which means you need more energy than you have to make the second quarter the same size.
It's true that higher g causes more induced drag, but the predominant factor is slowing airspeed whenever the nose is pointing higher than the plane can sustain in climb. Higher g in the initial pull means more airspeed when you reach vertical, up to at least 7g in the airplanes I've flown that can use more than 6g safely. Four g is about the minimum for a round loop in a variety of planes, and 5g usually works better. I haven't had my loops assessed from the ground in an RV, but they feel pretty much the same as any other aerobatic plane I've flown.
Of course, this only matters if you're aiming to fly to competition standards. For airshows or recreational aerobatics egg-shaped loops are perfectly fine.
It's true that higher g causes more induced drag, but the predominant factor is slowing airspeed whenever the nose is pointing higher than the plane can sustain in climb. Higher g in the initial pull means more airspeed when you reach vertical, up to at least 7g in the airplanes I've flown that can use more than 6g safely. Four g is about the minimum for a round loop in a variety of planes, and 5g usually works better. I haven't had my loops assessed from the ground in an RV, but they feel pretty much the same as any other aerobatic plane I've flown.
Of course, this only matters if you're aiming to fly to competition standards. For airshows or recreational aerobatics egg-shaped loops are perfectly fine.
Daveflier
Member
I fly the sportsman catalog in an RV-8 usually three times a week. Aerosport IO-375, full Raven inverted, flop tune in right tank( countless times finishing the sequence and realizing I forgot to use the correct tank). Nose heavy Hartzell prop, with an ETX Lithium on the firewall. Followed Ron Schreck’s research and have 18.8 lbs of ballast at station 224.88. Once I did that…..an entirely new aircraft. I don’t even have the seat cushions installed in the passenger seat. With 10 gallons a side at takeoff, my weight with me plus parachute is 1515lbs. Right at the middle of the CG envelope. In general, the faster you fly the maneuver….the better.
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ronschreck
Well Known Member
Hi Dave,
Great to hear you are enjoying aerobatics. Are you competing?
Your RV-8 started out being nose heavy so you can probably put a bit more weight in the tail. I had a composite prop and Oddesy batteries (2) in the front and rear baggage compartments. Nineteen pounds put my CG one inch forward of the aft aerobatic CG limit. Different fuel loads barely moved the CG. With the aft CG you may be tempted to try inverted spins and snap rolls. I found the sweet spot for snap roll entry is 100-110 knots. At that entry speed I never came close to over G. I usually experienced 3 to 3.5 Gs with that snap entry speed. I realize that the G meter doesn't measure asymmetric Gs but I assure you that you are well below the limit. You could stress the structure if you tried snaps closer to Va. Snap entry does NOT require slamming the elevator or rudder to the stops! A quick jerk to about half travel on the elevator will bring the angle of attack near to a stall. Rapid application of (left) rudder should cause the (left) wing to stall and around you go. Snaps to the right are just as easy. The secret is PRACTICE. Once you get the timing down they become easy, repeatable and predictable. Note that I never mentioned ailerons. Keep them neutral!
Hope you get into competition. It's a lot of fun and you will enjoy the company!
Ron S.
gmcjetpilot
Well Known Member
Age of thread aside thought I'd reply. Just asking. Its your plane and you are PIC. RV-8 erobatic Wt. 1550 or 1600lbs (later model) and CG range is from 15% to 25% MAC for aerobatic?
Two chutes, 15lbs each, 30lbs for two. Assume 2 x 190lb pilot/pax w/ gear, 16 gal x 6lbs/gal, BOW needs to be 1050lbs to 1100lbs. If passenger is tiny or fly with less fuel reserves it can help a bit.
Many RV's over the years end up with BOW higher than Van's design BOW, making true 2 up Acro a challange. RV-4 and 6 have lower aerobatic weight limits.
No shame in solo aerobatics and in some cases it is wise and prudent if you can't comply with all limits and FAR's.
Has anyone demonstrated recovery in an RV-8 a fom a fully developed spin at 25% MAC and 1600lbs? Just woundering.
ronschreck
Well Known Member
Did anyone imply that it is shameful to fly solo aerobatics? I maintain that is is wise and prudent to do so!
Never did spins at full aft aerobatic CG limit. No problem with CG one inch forward of aft limit.
gmcjetpilot
Well Known Member
Oh competition. Great. Most are not doing aerobatics in competition, so my comment is for novice. You seem to have throw it out as recommended. I Sportsman a challange in RV's, at least to be competitive. Tjis level can be done w/o inverted fuel/oil supposedly. With 45 degree inverted lines it's marginal. Plan on cleaning oil from belly.
Most common wisdom by people smarter than me RV's are not suited for competitive aerobatics. Speed and G's to stay in the box is a challange.
Agree comply with limits and regulations.
Unfortunately the owner of the RV7 I flew some aerobatics in didn't want me to snap it, so I know nothing about RV snaps. However, someday an RV4 or 8 will be my last airplane and I certainly plan to snap it.
l'm curious about your reason for not suggesting unloading after the break. My experience with two monoplanes and three biplanes (from Sportsman to Unlimited) is that pushing the stick forward to resistance after the break always improves the snap. Less energy is lost because of the smaller difference between the fuselage angle and the roll axis and because the roll rate is faster, and recovery is usually more predictable. The g load is reduced a bit but the difference in lift between the two sides is increased, so there's probably little change in the overall load on the airframe. Is there something about the RV snap that makes unloading unadvisable?
Nah, wisdom is knowing when to comment and when to refrain, based on actual experience. Bill McLean "unwisely" flew his RV-4 to a 2nd place NATIONALS finish in Sportsman in 2016, and Ron Schreck and Jerry Esquenazi whipped plenty of Extras and Pitts in Intermediate in their RV-8s during their time flying RVs in the sport. Competition acro requires a self-starter attitude. Not everyone has this.
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RV8JD
Well Known Member
Here is Van's take on IAC aerobatics:
IAC Aerobatics in RVs by Dick "Van" VanGrunsven (with a sidebar on preparing your RV for aerobatic flight by Ron Schreck)
"SUMMARY
All RV models listed by Van’s Aircraft as hav-
ing aerobatic structural limits are suitable
for IAC Primary and Sportsman level com-
petitions, and even Intermediate level in the
hands of more experienced pilots.
...
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."
ronschreck
Well Known Member
I should have mentioned that unloading after the break and right after rotation starts is necessary. Unloading does make for faster rotation. Failing to unload will make for a sluggish roll. I think RVs respond to control inputs during a snap roll just like dedicated aerobatic planes but the speed of rotation is probably slower than most.
ronrapp
Well Known Member
Nah.
I've been flying, competing, coaching, and judging aerobatics for 20 years. I've seen W670 powered Stearmans win in Sportsman. Ditto for Citabrias and J-3s. I used to get beaten in Intermediate by a low-powered open-cockpit Great Lakes. He had to take breaks to make it through the sequence, and he STILL beat me more often than not.
Even in Advanced, the partners in my S-2B would typically beat the Edges and Extras. I wasn't quite as successful in that category, but I also didn't fly it for as long as they did.
But the RV? It can do Sportsman all day with ease, even smaller horsepower engines with a fixed pitch prop, and be extremely competitive. Whether you're talking about recreational aerobatics or IAC events, it's more about the pilot than the aircraft.
If I've learned anything over the past 20 years, I've learned that.
--Ron
ronschreck
Well Known Member
Hey Ron R.
All well said! I think my determination to squeeze every bit of performance out of my RV in competition was more about proving to myself that I could do it. Many have asked me why I didn't upgrade to an Extra or some other dedicated aerobatic aircraft and it all comes back to facing a challenge; to push that little RV beyond what everyone expected it was capable of. And the thrill of beating a few Extras and Pitts along the way was worth the effort. Ron, you are right, the RVs are very capable of winning at the Sportsman level of IAC competition and we have even challenged the field at the Intermediate level. Now if Dick VanG would just make an RV that can stand up to tail slides we might even give Advanced a try!
Ron S.
smithflys23
Well Known Member
I agree with Dave, and Ron.
More smash = more energy.
Good luck stringing maneuvers at 140 kts.
I consider Ron an expert in RV aerobatics. Considering his pedigree, perhaps you should as well.
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jull_under
Active Member
Question on “No need to throttle back”.
How about FP props. I have a wood Ed Sterba prop & O-320 160HP on my RV-4.
I am looking for an RV aerobatic instructor in the SoCal area so I can learn how to do this thing properly. My RV8 is out of phase 1 and thus I can fly to the training airport within a reasonable travel distance.
My plane has a IO-360 with the adjustable FP propeller.
I am appreciated if you can send recommendation.
Thanks
My plane has a IO-360 with the adjustable FP propeller.
I am appreciated if you can send recommendation.
Thanks
Forgot how good you were !!!
ronschreck
Well Known Member
I hope Bill McLean will chime in here. Bill has championed his fixed pitch RV-4 in IAC competition for years and placed second in Sportsman at the 2016 Nationals at the age of 75! I can tell you that just as we stress the importance of respecting the published aerobatic limits of the airplane you should also respect the limits of the engine when dancing around the edge of the flight envelope. Having said that I know that many Pitts drivers and others regularly see something north of 3000 RPM when flying aerobatics. Perhaps they might also chime in here. From what I have seen on the competition stage, having a fixed pitch prop is not a handicap and for those who are equipping their RV for aerobatics I would consider inverted oil and a ratcheting seat belt long before shelling out the bucks for a constant speed propeller.
Since you asked . . . I put about 1000 hours on an S-1S. The first 700 were with a metal Sensenich pitched at 60 inches. That combination saw 3300 RPM many times every practice flight. Occasionally 3500 when I needed VNE to pull to vertical, outside snap, fly away from the top (at 6000 ft DA). Later I pumped up the engine with higher compression and cold air induction and switched to a wood MT that was pitched at about 63. That prop was limited to 3100 and I got a better top end while the engine mods gave me about the same low speed acceleration.
I had the engine pulled apart at 1200 hours because of a small amount of metal in the oil screen. That came from the tach drive, which was upgraded on later engines. The rest of the engine looked fine according to the engine shop but I replaced the bearings while it was apart. It probably wouldn't have made 2000 hours based on the bearing wear, but Lycoming says the TBO on that model of IO 360 is 1600 when used for aerobatics and I expect it would have made that if not for the tach drive issue. It's impossible to know how much of the wear was due to the absence of an air filter, but that probably contributed as the bearings felt like 1500 grit sandpaper.
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ronschreck
Well Known Member
Many thanks for this post. IMHO most RV pilots tend to be rather conservative when it comes to pushing their planes to the edges of the flight envelope and engines to the manufacturer's "recommended" limits. The sound of a Lycoming at full song at 3500 RPM is not soon forgotten. Aah, music to my ears! And while I caution pilots to exceed Lycoming max RPM limitations at their own risk I am certainly not recommending that an engine teardown and inspection is warranted just because the indicated RPM once exceeded 2700. In that case I would look for corroborating evidence of engine damage (rough running, unusual vibration, smoke, unusual noises, etc). If none is evident, press on. It is incumbent on aerobatic pilots to be especially attentive to the care and maintenance of their planes. RVs are tough by design and can easily withstand the rigors of aerobatic flight but you must keep up with regular maintenance and inspections. (Sermon over...)
ronrapp
Well Known Member
That's the S-1 scene. Such a different experience. In an S-2 you would not want to run it that way. The props take a huge beating in Adv/Unlimited levels because of the gyroscopics. My S-2B once had a broken crankshaft from that. But it saw a LOT of accelerated and flat spins, crossover spins, hard inside and outside snaps rolls, and probably flew 200 or more hours a year of hard acro. After that, we switched from a 2 blade metal prop to a 3 blade MTV-9 series and never had another problem. Well, with the prop that is. Broken longerons, leading edge nails coming out, and a million other maintenance issues, sure. But the propeller was solid.
--Ron
Flyingleap
Well Known Member
I put 795hrs in a Pitts S1S and loved every second of it.
And yes, 3500 occasionally, most of the time 3200/3300. Asked a couple of LYC reps at OSH
about that and they said " don't worry until you get to 4000".
Also, fuel at a minimum.....what a difference.
Have you ever figured the the rate of descent in spins at about 200mph to keep a nice down line, like 16,000fpm and 300 ft/sec, happens fast, try to keep up!!
There was a 'cable' from the engine to the firewall in case the engine blewup and tried to leave the airplane. It was there because it happened !!
Another thing.... Always do a postflight inspection and a preflight inspection. Don't laugh, just do it!!
