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  #21  
Old 12-31-2017, 10:54 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,643
Default Spins

Most of the biplanes are far more prone to inadvertent spins than the monoplanes, the Sukoi being an exception. The Pitts S2B will probably do at least 10 and maybe 20/30 flat spins out of botched immelmans for every one out of a hammer. It was so common that I started calling it the immelspin. The scenario is half roll started with nose way too high,low on speed, when the roll doesn't stop as desired full right stick, when things get even worse, full back stick and off we go. On the other hand the S2B with cg well forward, is very difficult to get to inverted flat spin with a normal power off entry. If the spin is established and then the power is added too aggressively the airplane will often roll upright as power is applied. Note that this is only with cg well forward.
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  #22  
Old 01-01-2018, 06:18 AM
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ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gilbert, AZ
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Default

Quote:
Originally Posted by greghughespdx View Post
Cool - any video of the snaps? Would be fun to see.
There's a half snap at 1:10 and a quarter rolling circle at 3:05.

https://www.youtube.com/watch?v=gNNK...7bNsPg&index=1
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IAC National Judge
RV-8, "Miss Izzy", 2250 Hours- Sold
My Aerobatic Video
My Formation Video
CAF B-25 - Airbase Arizona
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  #23  
Old 01-01-2018, 08:44 AM
fbrewer fbrewer is offline
 
Join Date: Sep 2017
Location: Leander
Posts: 99
Default

Ron,

What IAC class was the video from?

Is this typical of an IAC performance?

I know almost nothing about IAC
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  #24  
Old 01-01-2018, 10:03 AM
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ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gilbert, AZ
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Quote:
Originally Posted by fbrewer View Post
Ron,

What IAC class was the video from?

Is this typical of an IAC performance?

I know almost nothing about IAC
This is the 2016 Intermediate Known sequence that I flew at the East Coast Aerobatic Championships at Warrenton, VA in September.
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Ron Schreck
IAC National Judge
RV-8, "Miss Izzy", 2250 Hours- Sold
My Aerobatic Video
My Formation Video
CAF B-25 - Airbase Arizona
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  #25  
Old 01-01-2018, 11:33 AM
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Gash Gash is offline
 
Join Date: Aug 2009
Location: Goodyear, Arizona
Posts: 949
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That's a great video Ron! Nicely flown!
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  #26  
Old 01-02-2018, 07:31 AM
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ronschreck ronschreck is offline
 
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Location: Gilbert, AZ
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Quote:
Originally Posted by Gash View Post
That's a great video Ron! Nicely flown!
It's entertaining but also very revealing of the painfully slow roll rate of the RV. In the 1990s the father and son team of Ralph and Scott Riddell campaigned a RV-4 with full-span ailerons. Scott flew it in Advanced and did quite well. To my mind, the slow roll rate of RVs is the biggest drawback, performance wise and the biggest barrier to consistent wins at the Intermediate level. I once flew Jerry Esquenazi's RV-8 and found the roll rate of his -8 to be faster than mine. Why? I don't know. I'm busy rebuilding my engine and installing a new canopy so aileron surgery would be a good project if anyone has any good ideas...
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IAC National Judge
RV-8, "Miss Izzy", 2250 Hours- Sold
My Aerobatic Video
My Formation Video
CAF B-25 - Airbase Arizona
VAF 2022 Donor
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  #27  
Old 01-02-2018, 08:01 AM
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Saville Saville is offline
 
Join Date: May 2014
Location: KBVY Massachusetts
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Quote:
Originally Posted by WillyEyeBall View Post
Having done hundreds of inverted spins in my RV4 since it's in my free style for competition for the last three years, I can offer some advice. It takes specific inputs, attitude, and timing to make an RV spin inverted as other RV competitors will concur. I received advanced instruction in an Extra 300 before I tried it. Here's a video of a botched hammerhead that starts a tail slide and possible inverted spin at the 1 minute point, but it never gets to the rotation part:
https://www.youtube.com/watch?v=GLed3Zg40mI

The error with this hammer head was dragging the right wing, kicking left rudder too late which wasn't effective in rotating the nose down.
Be careful and hope to see y'all in the box this year,
Bill McLean
RV-4 slider
lower AL (roll tide)
Willie,

Is your "spider" drawn on the canopy? If so what did you use to draw it?
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  #28  
Old 01-02-2018, 08:08 AM
Pablo Pablo is offline
 
Join Date: Aug 2008
Location: Frederick, MD
Posts: 80
Default Really impressive flying!

I didn't know the RV-8 could look that sharp in the Intermediate category, and the half-snap looked really solid. The slow roll rate at slow speed is certainly a drawback, but the maneuvers sure looked crisp and symmetrical. I assume you've got an inverted oil system for the sustained negative Gs required on some of those figures. Any other modifications?

Dave
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  #29  
Old 01-02-2018, 10:09 AM
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ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gilbert, AZ
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Quote:
Originally Posted by Pablo View Post
I didn't know the RV-8 could look that sharp in the Intermediate category, and the half-snap looked really solid. The slow roll rate at slow speed is certainly a drawback, but the maneuvers sure looked crisp and symmetrical. I assume you've got an inverted oil system for the sustained negative Gs required on some of those figures. Any other modifications?

Dave
Hi Pablo,

Good to hear from you! Sure enjoy reading about your adventures and really jealous to see all the cool airplanes you get to fly. Hope one of them takes you down my way before long.

Sure, I have inverted oil as well as an oil accumulator, inverted fuel, etc. Even those without inverted systems can compete if you are willing to spend a bit of time cleaning the belly. There are no sustained inverted maneuvers in IAC competition at this level so oil starvation may only happen for a few short seconds for those without inverted oil. It poses no harm to the engine. Those with constant speed props should be careful to pull back the power quickly if the prop goes to low pitch due to oil starvation but that should not be an obstacle to competition or recreational aerobatics.
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IAC National Judge
RV-8, "Miss Izzy", 2250 Hours- Sold
My Aerobatic Video
My Formation Video
CAF B-25 - Airbase Arizona
VAF 2022 Donor
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  #30  
Old 01-02-2018, 12:34 PM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Quote:
Originally Posted by ronschreck View Post
I once flew Jerry Esquenazi's RV-8 and found the roll rate of his -8 to be faster than mine. Why? I don't know. I'm busy rebuilding my engine and installing a new canopy so aileron surgery would be a good project if anyone has any good ideas...
I don't know if it is a factor for your airplane or not Ron, but aileron shape can have some influence on max roll rate (though I don't think it would be a big difference).

If the aileron trailing edges are not properly formed with the skin profile flat along the cord line right to the tight bend radius of the training edge it will make the ailerons behave as though they were slightly narrower in cord which will also reduce there effectiveness slightly. A secondary influence is that it will also make the stick forces in roll lighter.

So if yours are not finished correctly you might get a bit more effectiveness by correcting that, but the trade off will be a slightly higher stick force.
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Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
FAA/DAR
RV-6A (aka "Junkyard Special ")
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