First Flights of a Sports Panther

[mayo3808]

Thanks Bob for the updates and write ups. I look forward to seeing your airplane when it get out of the paint shop.

[Jinkers]

Bob,

Great write ups, I've enjoyed reading them. Thanks for taking the time to keep us all up to date... Any chance you have a builders website to look over?

Thanks,

[woolleys]

Just a quick update on the status of my Panther. Some three weeks ago I finished the phase one fly off time and transition the aircraft into phase two. The numbers and performance that were reported in previous posts were confirmed. Additional testing with aft CG and hard aerobatics confirmed that the panther was stable throughout the operating range. A note on the aft CG testing revealed that during pattern work, the stick forces were generally light and required a light touch on the stick. Top speeds remain in the 195 MPH range at low altitude with TAS in the 180 MPH range at 7500 feet. Since I spend much of my time with this airplane doing aerobatics and chasing RV's around, fuel consumption various greatly. The small amount of cruise flight at medium altitudes indicated that the 0320 will burn about 6.5 GPH at 2450 RPM's a cruise at 160 IAS.

I pushed the airplane into some serious gusty crosswinds with demonstrated landings at 20 MPH crosswind component. Due to the light weight of the panther is takes some aggressive control inputs. Of course, wheel landings, I found, was the preferred method of landing. Aileron and rudder control was sufficient and a wing low touchdown was easily done. The airplane did have a tendency to try and fly during the transition to the three point attitude and small inputs and quick rudder control was necessary during this transition period. Grass operations with these type of crosswinds were much easier than pavement. For strong crosswinds on pavement, you have to be on your rudder game to keep the airplane straight. For my airplane the stall speed is just below the 3 point touchdown, thus to get a full stall 3 point landing you will have to drag the tailwheel first.

The last 20 or so hours were spent doing hard aerobatics with spins, snap rolls, vertical and rolling aerobatics. Driving the aircraft hard with up to 5 + G's has seen good manners with accelerated and low speed stalls. The only noted issue is that if you don't have a centered ball the aircraft will have a tendency to drop a wing very rapidly; usually the top wing in a turn. If the G's are not release it will tend to snap inverted. Recovery is easily accomplished with a slight release in back pressure. The heavy fuselage rumble will give you plenty of warning and is easily controllable with stick forces. These conditions usually occurred when I had input full aileron and rudder to get maximum turn/roll rate out of the airplane and demanded more lift than was available. The only noted grip and this is minor, with max. aileron deflection at higher speeds the control forces are quiet heavy but manageable. Dan is working this issue and spades are being considered. The nature of the design for aileron construction, which is less complicated than the RV's, is the trade off. Most pilots will not even consider this an issue except for the most aggressive flying types.

I made the decision to have the Panther painted right after Phase 2. I did not have any major mods., except for resetting the angle of incident on the horizontal stab. and thus it was ready to go to the paint both. And here is where the design and ease of assemble and disassemble paid off. It took me about 3 hours to take the wings, cowl, ailerons, flaps, canopy, elevators, and rudder off. I will attempt to post some pictures once it out of paint and back together.

Each builder has his own set of criteria for why and how he/she is going to use the Panther. By virtue of it being a single seat it has a generally focused mission; solo flight for sure and most likely a sports machine for short hops and just fun operations. It is comfortable and cross country operations is not out of the question. It carries enough fuel to have sufficient legs for traveling and will allow enough room for necessary baggage. So as you progress in your building efforts, be assured that the end product is a quality flying machine that will take the hard punishment that I inflict and still look good and have good flying manners for those who just want to enjoy the experience of flight.

Bringing a new aircraft to the homebuilt market is a serious task and generally has serious teething problems with, sometimes, serious design changes as the product is put into the hands of the 200 hr. private pilot or the 9000 hr. fighter pilot. Dan and Rachel's background and experience has resulted in a superb product that hit the mark on their first pass. I'm sure there will be revisions and updates to both the construction process and product improvement. But to have the performance that I see out of the first customer example with no modifications is nothing short of outstanding.

Once again ladies and gentlemen, I predict you are going to enjoy the end product.

[I_FLY_LOW]

Freakin' awesome!!!! Congrats!!

[Rpellicciotti]

Bob.
Thanks for these detailed reports. I am really enjoying reading them. Did you happen to compute your TAS at altitude? Looking forward to more!

Rick Pellicciotti

[woolleys]

Progress report on flight testing the sport Panther. With just under 10 hours of flight time on the Panther I have acquired some solid data on performance and handling. I have finally got the whirlwind prop dialed in as close as I can. After numerous adjustment in pitch, (changing pitch 2 tenths at a time) I have an acceptably pitch setting of 21.3 degrees which gives me a 2200 rpm static and something just over 2700 R's top end. Speed at 1000 feet is 193 MPH indicated with more power available if prop rpm would allow. Takeoff at gross wt. is about 450 feet with a 750 climb rate the airspeed will accelerate to 115 MPH at the end of our 2200 foot runway. Climb rate at 120 and 2350 rpm is 1750 fpm. I have completed takeoffs with 10 degrees of flap and the takeoff roll is only reduced by 50 to 100 feet. It appears that the best climb speed will be around 120-130 with this prop and engine. Cruise at 6500 feet give a IAS of 165 at 2450 and 173 at 2550. Top speed at that altitude is 182.

Stall speeds on my airspeed is 57 mph clean and 53 full flaps. Recovery is instant with the release of back pressure. A slight right wing drop on this airplane and is more pronounced with full flaps. Accelerated stalls are straight forward with heavy fuselage rumble and a tendency to have a pronounced left/right wing drop depending on rudder position. Recovery is a simple matter of releasing the back pressure. On set of all stalls comes with little or no warning.

The airplane is very responsive and roll rates are crisp. If you want more roll apply following rudder and the airplane will turn on a dime. The Panther does wonderful positive aerobatics and with the 150 HP engine will do all the basic maneuvers with the power set at 75%. A loop can be accomplished at 135 mph without adding power and at 2.5 G's. The over the top airspeed will be around 60. The airplane is solid and has no bad habits during all flight regimes.

I built the Panther to be a highly maneuverable aircraft to provide an excellent platform to hassle with the local RV's. All are powered by 180HP and most have CS props. In the last couple of flights I have pushed the Panther against my neighbors RV 4. The Panther will match and generally exceed the RV's climb, will out accelerate and turn inside the RV. It will hang on the prop while RV falls. The Panther's advantage more that compensates for the 30 less horse power due to the weight advantage. This airplane is exactly what I wanted.

In the pattern, speed has to be managed with the FP prop. It does notslow down, but once at flap speed, my 50 degree of flaps bring the speed under control but you still have to be sparing with the power to control the speed. I have been flying 75 mph on final and it is well controlled and can do wheel and three points from that speed. Wheel landing are simple with the gear being very compliant and has no tendency to seem stiff. Three point landing are easily accomplished with three point touchdown just above a stall. Control throughout is firm and tracking after touchdown is straight. The rudder is very effective and needs little input for control:habits both on pavement and grass are very straight forward and will not surprise you with odd inputs. The one thing that is a to be mentioned here, with the spread of age in ones bottom, and the flap lever being fairly close to your left hip, when you retract the flaps on landing I have the need to shift my body to the right to clear my rear end. The first time I did this on pavement, that shift cause a input of rudder as I shifted. Remember the part about the rudder being very effective. The airplane responded very quickly. Be aware. For you slim trim guys/girls it will not be a problem.

The Panther is living up to my expectations and is exactly what I hope it would be. It will be interesting to see how Buddy Henson long wing 0 320 performs. It should be a stellar performers also.

[psalter]

Saturday Dan couldn't stand being on the ground with another Panther in the air. So Dan joined in on the fun.

wingman.jpg

It is always good to have a wing man especially when it is another Panther.

Panther manuevering.jpg

Of course, they engaged in some maneuvering.

crossing.jpg

having fun.jpg

I think Bob is having a lot of fun. Check out that grin. I have heard of the RV grin, well, this is the Panther grin.

We have a lot more pictures and videos, watch for future updates.

[Seansull]

Thanks Bob!! I really appreciate your detailed flight testing updates. I can't wait to get mine in the air too!


Sent from my iPhone using Tapatalk

[woolleys]

Panther testing continues with over 3 hours of flight time. During the last couple of flights I had the opportunity to fly formation with Dan and his prototype and with several 180 HP RV 4's. Light aerobatics and a incomplete stall series has been accomplished. Stall numbers are going to be around 57/59 Mph clean with 7 gallons of fuel aside. Characteristics are benign with a slight wing and nose drop. The airplane will immediately recover with releasing the back pressure and if the stick is held aft will drop and raise the nose with little tendency to roll off on a wing. Stall response is much like Dan's aircraft. Accelerated stalls results in a shutter with a slight wing drop depending on the rudder displacement. The aircraft has been flown to 4.2 G's and response well to stick input with good feed back and light pressures on the elevator. Slow speed characteristics are very predictable. The aircraft does smooth aerobatics with plenty of reserve power from the 150 HP engine and pulls over the top in a loop at 75% power and 2.5 G's. Roll rate is faster than Dan's long wing and with trailing rudder has a very impressive roll rate. Speed of over 210 have been seen in a slight dive and level speed at 1000 feet at 2700 R's is 191 mph, there was still throttle left, so there is more speed to be had under the right prop conditions. Over all I am well please with the Panther performance and based on what I'm seeing flying against the180 HP RVs it has excellent performance. Turn rate, climb and acceleration is excellent and will hold it's own against bigger HP machines. At 830 pounds it is almost 200 pound lighter that my and the other RVs on our field. After more time on the engine I will be able to explore the aggressive maneuvering aspect of the aircraft.

There is one detraction about the prop selection I made. I am running a Whirlwind ground adjustable prop with 72 inch blades. I have had some trouble getting the prop dialed in to take the speed and power of the Panther. The spread of static to top end is somewhere in the 600 + RPM range with the lower static set at 2250. That static gives sufficient HP for take off but does not keep the RPM under 2700. A lower static RPM results in reduce HP for takeoff and climb. It appears that the prop starts producing good thrust at or above 2400 RPMs; but his could be the result of getting the added HP with engine speed. Since the prop does not allow for operations above 2700 I can't tell how fast the engine will turn at full throttle. A smaller RPM range from static to full power would be helpful with the Panther and allow more proper use of the engine power and aircraft speed. When maneuvering with this prop at the current pitch setting it requires close attention to engine RPM to keep from over speeding. But considering landing speed in the 65 to 70 MPH range and top speed close to 200 MPH it is demanding a lot from a fixed pitch prop.

Flying formation with Dan in the prototype highlighted the HP difference in the two airplanes. The sport wing will easily cruise at 160 MPH at 2200 RPM's with Dan Corvair mounted Panther running close to max power. But with at least 50 extra HP it is expected that cruise would be in the 175 to 180 MPH range and with the shorter wing.

Guys and girls, keep building, you're going to enjoy the end product.

[ccsmith51]

Outstanding report BRB. Can I have your RV-4 now that the Panther is taking up the hangar space and your flying time!!!

Seriously, congratulations on another plane completion and the first Panther Sport flying. You are an inspiration to all!