0320 on LSA version

[psalter]

It is physically impossible to increase the max gross weight to 1320 lbs and still keep the LSA stall speed with the current design of the Panther.

Stall speed is a combination of 4 things, air density, wing area, weight and max lift coefficient.

Air density is not something we can really change obviously.

Max lift coefficient is set by the airfoil, most airfoils that work well at higher speeds use high lift devices to increase the max lift coefficient, but FAA regulations do not allow the use of high lift devices to lower the stall speed for the LSA category. They can be used, just not counted against stall speed. Most airfoils have very similar max lift coefficients without high lift devices. While there are some highly cambered airfoils that have great max lift coefficients, they come with penalties of high drag, and large pitch moment changes.

Wing area is the only thing that can really be changed, the LS series increases wing area for the stall speed. However, increasing wing area has other drawbacks: More weight because of heavier structure for the larger wing, larger tail because of the larger wing, more drag, usually causes a decrease in roll rates, and makes it harder to fold the wings and trailer.

Everything is a compromise to give the best performance for as many conditions as possible.

Unless your mission is to beat a high powered RV-4 or Panther in nearly all regimes, there is no reason you can't have just as much fun with a smaller engine. Bob just flew my Panther last night, (see his comments in the flight ops section). He had one key comment after flying it, "One great thing about Panthers, they all fly well regardless of the engine.". He did all the aerobatics you would expect for an aircraft with no inverted fuel and oil systems.

Dan and myself both tip the scales at more than 225 lbs and are around 6ft tall. That was one of the design criteria, fit larger pilots than nearly any similar aircraft.

[Maddpilot]

That was next question I had Joe. I'm a 225 pound 6' tall guy. Of course I need to shed a few pounds but am wondering if there are prospects of an increase in go for sport version?
And I know Dan, intent is keep weight and cost down to fit a niche'. I'm impressed with everything I've read and heard and seen of the panther. I have never tackled a build project but am almost ready to pull trigger and attempt a tail kit for starters. Also, I'm very interested in the corvair engine. Bare with me on perhaps some dumb/ or redundant questions. I'm reading as much as I can as I go here and I'm sure some answers may be posted elsewhere here. Thanks in advance guys!
Chris

[Lowrider]

What would it take to get to 1320 gross? There must be folks that tip the scale over 225 and might want to carry a bag too.

[Maddpilot]

How is the corvair engine in comparison? Performance, endurance, approx burn rates etc.

[danweseman]

Dan H
The big issue with using the 0-320 is the useful load.
The weight of Panther LS (long wing) in its lightest form (small tail wheel, light wheels and brakes ,no elevator balance ,no lights, auto pilots ,interior etc), using the lightest version 0-320 with light wood prop etc will weigh at least 825 lbs painted.
for comparison ,currently unpainted 0-320 powered Panther LS empty weights range from 821-851 empty.
Assuming you build super light and have a 825 lbs airplane ,at 1115 gross weight you will have 290 lbs for pilot fuel etc.
SO a 170 lbs pilot would be able to carry 20 gal off fuel.The big thing is that at 138 MPH "lsa max speed"
the 0320 will have a very low fuel burn ,likely under 5 gal per hr so you would have a decent endurance.
This was a very optimistic example. If you end up with a 865 lbs Panther, And weight 220 lbs...... you can carry 5 gal of gas.....
I should also note that SPA does not officially "recommend" or support the 0-320 (or any of the heavy engines) as power plants for the Panther LS.
Dan W

[Tony Spicer]

http://flywithspa.com/panther-completions/

Apparently Buddy and Will are still looking for scales. If you intend to paint, add about 25 lbs.

Tony

[PlaneDan]

Is there an issue with staying within the LSA criteria given the extra weight of the 0320?