Panther, Cougar, and C-3400 Potential Performance

[rludtke]

Hi Dan,
Actually, your roll technique is spot on. The airplane needs to draw a horizontal line. The judges are trained not to look at the airplanes attitude, but the line it draws. Naturally float carb airplanes have a bit of a disadvantage, unless the pilot is willing to let the engine quit during the inverted nose high attitude "push". But like you said, you can wait until you get to knife edge, then kick the nose back up again, and not loose power. This isn't always caught, and if it is, it wouldn't be a significant markdown.

Thanks for the dialog Dan, this is fun. Have a Happy Thanksgiving.

Rick

[danweseman]

Rick, with the current float carb I cannot do a true slow roll the engine stumbles instantly upon easing the stick forward as I pass through inverted. I can fake it pretty well ,enough so that my friends ask me how I can do it, but judges would see my fake(using to much rudder on first and last 90 degrees to keep nose up). Also the extended 45 degree down lines can be troublesome. in general I tend to keep the maneuvers small so the time exposed to "0" g is limited. Will see what I can do when weather improves
Dan

[rludtke]

I don't will try to do the above sequence (improvised for the lack of negative G ability) and post both a cockpit( GO PRO ) and ground video ,as long as you guys promise not to laugh...at least not loud enough for me to hear...
on the "saw tooths" what is flown at the tops and bottoms .just a pull to vertical then horizontal?

Hi Dan, thanks for your response. It sounds like the Panther has more vertical performance than I expected. Penetration is commonly inadequate in light airplanes of my experience, but perhaps not with the Panther. That is cool.

The Sportsman sequence is designed for airplanes without inverted systems, so you shouldn't have any trouble flying it as drawn. however, keep in mind that you don't actually fly it as drawn. It is impossibly to not have a radius in each pull. What you can do though is try to make the radius at the sharp corners smaller than the radius for a loop. The Humpty Bump for instance, can be flown using your hammer head speeds. Pull to vertical, when aileron input will no longer prevent torque roll, pull over the top to a vertical down line, and pull to horizontal when you get your desired speed for the next maneuver. The low speed over the top will result in a very small radius.

Sawtooths are represented in symbology as having a sharp corner at the top and bottom. The top radius will be small as the speed is low. The pulls to horizontal will not be sharp like they are drawn, so don't try. A radius can not be avoided. In my old Pitts, I would pull 6 Gs in a pull up to vertical up line, or a pull from a vertical downline to horizontal. But I did so only because testing determined that this gave me the best trade of drag loss. 4Gs resulted in a longer exposure to the drag of the pull, a larger radius, and a slower exit speed. 6Gs resulted in shorter exposure, tighter radius, and a longer vertical up line. The best G for a high energy corner will vary for each airplane.

A very short primer on IAC competition styled flying:
1) All maneuvers start and end on a horizontal line.
2) All lines are horizontal, vertical or 45 degrees.
3) Maneuvers can be placed on lines or loops.
4) Lines are judged by the angles they appear to have from the ground
Which can be quite different and even incorrect from the pilots view point.
5) Loops are round as viewed from the ground.
Therefore, they do not have a constant angular velocity from the pilots view point. In fact, it may be necessary to have a period of zero angular velocity over the top (e.g. strait line) to create a round appearance.
6) The beginning, end, or a break in the sequence is signified with a "wing wag"
Which is three crisp dips of the wing preferably toward the judges (it is considered bad form to reveal your belly to the judges )
7) Crisp arrivals on a line is rewarded
Show the judges that you are on the line by holding the G to the last moment, then reverse the stick input to immediately stop the pitch inertia.
8) Smoothness is rewarded
It is possible to be smooth and crisp, but always start with smooth, crisp can come later.
9) Maneuvers such as rolls need to be centered on the line.
This is tough to do in a vertical roll. I do know some Suhkoi drivers who purposely got called for "long after" just because they could.
10) The heart of a maneuver is placed in the center of its third of the box
The box is a cube 3000' in each direction. From the judges view point, it is subdivided into thirds- left center and right. Maneuvers shown in the diagram on the left, should be centered in that left third, and so on.
11) The top of the box is 3000' agl.
The box actually goes to the earth for Unlimited, but a bottom is placed at differing levels for the remaining categories. Sportsman is 1500' agl. Effectively then you are contained to 1500 vertical feet, however, nobody gets called for out the box high, unless it is extremely obvious. In reality, rarely does anyone ever get near the top of the box after they first dive in. Energy management tends to be a downhill game.

For comparison sake, my 180+ hp fixed pitch (76x60 cruise prop) Pitts S-1E with factory T model wings installed (360 d/s roll rate) would just barely complete one vertical roll, draw a short line, and still be able to fly away at the top (albeit at zero G). An entry speed of ~180 mph and a 6G pull would generate a 1200' increase of altitude at the end of the maneuver. My fighting weight with partial fuel resulted in ~5:1 power to weight ratio. My top dive speed which seemed to be prop limited was 220 mph. This is the speed I would begin a sequence with after a 45 degree down line dive into the box.

You won't hear any laughter from me Dan, as anything you do will be far better than anything I could do now. I haven't flown in more than 15 years. Your Cougar's affordability is key to getting my butt back in the air.

I look forward to seeing your results.

Cheers,

Rick

[danweseman]

Rick, great questions!
Tony is right , the Panther will do anything the Sonex and RV aircraft will do. I don't compete , but do fly in a "box" environment when I go out to do "Play" acro. I typically start each flight with TO and climb at 120 mph to 1500 ft agl (about 1 min with half tanks me and chute). I then do my clearing turn and line up with runway(but displaced about 1500 feet so not directly above hangars and homes) I come out of clearing turns with about 80% power 150 mph. I typically do a Cuban 8, two consecutive loops, a hammerhead, two barrel rolls in opposite directions a half Cuban then pull to a 45 up line and decelerate in to a spin of 2-3 turns,then another hammer a aileron roll ,a 4 point aileron roll and a half Cuban,then a 45 up into a split S. I don't always do in exact order but do each of these maneuvers at least once. I will gain altitude doing this ,if not careful . I usually adjust on up and down lines to hammers and spins. If I did this a 100% power I would punch out of th top of box.
Panther prototype (LSA)weaknesses
1 slow roll rate. it about the same as a sonex ,a little less than RV, 150-160 degrees per second
We are going to test a aileron for LSA with more area and if forces get high spades.
2 MA3 carburetor hates even a hint of negative. So we cant even dabble with extending inverted sections,rolls must stay positive, and caution must be used on hammers. I routinely have to restart engine during aggressive flight.
Fix = Ellison TB runs great on the Corvair so will be switching some time soon.
3 spins and snaps. the Panther must be forced to spin...and snap also. the light wing loading for LSA and thich wing with large LE radius just dosnt allow a real clean entry. even shifting the CG back to 30% dosnt help as much as id hope. Maybe going a little further aft, or stall strips would help.more stuff to play with...

Panther Strengths
1 5 point harness standard. canopy and cockpit set for quick depart if chute use is needed.
2 The panther retains energy very well ,and can maneuver tight spaces. the current 3.0l engine @100hp and(called 120 others)and correct is plenty for the above manuvers. If you used VNE (200 MPH) entry the humpty would (from memeory) over 1000 ft. tall ?
3 panther presents well in the air and makes you look better than you are.
4 light control forces with long stick and rudder pedal travel make flying acro in turbulence easier than in some others aircraft I've flown (sonex)

I don't will try to do the above sequence (improvised for the lack of negative G ability) and post both a cockpit( GO PRO ) and ground video ,as long as you guys promise not to laugh...at least not loud enough for me to hear...
on the "saw tooths" what is flown at the tops and bottoms .just a pull to vertical then horizontal?

PS Cougar will be very similar to Panther when flown solo and with light fuel load.
Hope this helps Dan (904 563 4337)

[rludtke]

Thanks Tony, I wasn't aware. 2nd place with 80 hp has got to be a testament of both pilot skill, and aircraft performance. I'm impressed.

But could you or anyone else elaborate? I'd like to learn more about the airplanes (in this case the Sonex's) strengths and weakness' in competition, as it probably does compare well with the Panther.

And Dan, if you wouldn't mind sharing your thoughts on the Panther's abilities in the box I would really appreciate it.

Thanks all
Rick Ludtke

[rlweseman]

Rick,

What a Sonex can do, so can a Panther/Cougar! Joe Haycraft has flown both a 80hp AeroVee powered Sonex and a Jab 3300 powered Sonex in Sportsman.

https://picasaweb.google.com/lh/photo/z ... Jy0liipFm0

http://www.usnationalaerobatics.org/IAC ... testID=392

Tony

Good point Tony! Thanks!

[Tony Spicer]

Hello SPA,
I wish to say that your Panther is a brilliant concept, followed up with fantastic execution. Thank you for your ingenuity and vision.

I desire to find a two place LSA design that could be reasonably competitive (assuming reasonable pilot skill) in the IAC sportsman category (with no passenger of course). I am curious about your thoughts on the potential performance of the Panther and the future Cougar equipped with the future 3400 Corvair.

Rick,

What a Sonex can do, so can a Panther/Cougar! Joe Haycraft has flown both a 80hp AeroVee powered Sonex and a Jab 3300 powered Sonex in Sportsman.

https://picasaweb.google.com/lh/photo/z ... Jy0liipFm0

http://www.usnationalaerobatics.org/IAC ... testID=392

Tony

[rludtke]

Hello SPA,
I wish to say that your Panther is a brilliant concept, followed up with fantastic execution. Thank you for your ingenuity and vision.

I desire to find a two place LSA design that could be reasonably competitive (assuming reasonable pilot skill) in the IAC sportsman category (with no passenger of course). I am curious about your thoughts on the potential performance of the Panther and the future Cougar equipped with the future 3400 Corvair.

Have you flown the IAC Sportsman Known sequence in the Panther? If you haven't, please consider doing so, as it would help you formulate your response to my question that follows. Consider capturing your sequence flight(s) on video.

Would you be willing to, based upon what you know of the Panthers current performance, extrapolate what its performance could potentially be with the 3400? Then perhaps you could consider how the Cougar may be similar or different? I won't hold you to these estimates, I am just curious of what you think. Try to quantify the airplanes performance in terms of the expected ability to complete the 2013 IAC Sportsman Known sequence. Consider entry speeds, exit speeds, places in the sequence that altitude could be lost, places in the sequence that altitude could be gained, and any maneuvers that may not score well, or may not be completed because of performance limitations (if any).

2013SportsmanKnown.jpg

For those readers who are not familiar with the Aresti symbols, here is a list and description of the maneuvers:
1) Humpty Bump pull to vertical up line, pull over the top to vertical down line, pull to horizontal
2) Hammerhead
3) Saw Tooth with half roll on 45 degree up line
4) Loop
5) Reverse Saw Tooth with 2 point half roll on the 45 degree down line
6) Cuban Eight with 2 point half roll on first 45 degree down line, half roll on the second 45 degree down line
7) Immeleman (1/2 loop, 1/2 roll)
8) Two point roll
9) I'm not sure if this has a name, but it is a variation of the Immelman: a 45 degree down line, with a continuous pull into a 5/8 loop to horizontal and a 1/2 roll
10) Slow roll.

Performance assumptions:
Sequence will begin from level flight following maximum aircraft speed dive.
No regard will be placed on maneuver position in relation to ground references
Maneuvers will be flown with no break if possible. if not possible, note where and why the break was made in the sequence, for instance "inadequate speed to enter next maneuver". (Breaks are not bad. IAC allows mid-sequence stops and re-starts, and these breaks often leads to less downgrades than a poorly executed maneuver. A low-performance airplane can still be competitive with a strategically placed break to climb for altitude, dive back in, and restart.)

I realize this is a lot to ask, but I think it would be very informative for potential customers like myself who suspect that your products may provide an affordable path back into IAC competition.

I look forward to your response.
Rick Ludtke