O-200 and cowl

[danweseman]

Rick that could be a very detailed post
Generally speaking ,In the most basic terms shortening the wing shifts the load distribution closer to the fuselage and allows the wing to support more load at the same stress level. Think of your CG calculation
load x arm = moment , you can have many different combinations that result in the same moment

Many aerodynamic loads we calculate during the design of an airframes structure are based on wing loading. So as wing loading goes up loads on loads on tail, control surfaces etc. go up also. The Panther was designed to cover a wide range of loading conditions.

[at7000ft]

Question for Dan W - why does decreasing the wingspan allow for a higher gross with the same design limits as the wider span?

rh

[psalter]

One thing I will add to Dan's statement, first rule of aircraft design or buying an aircraft is "define your mission".

Everything about aircraft design is a compromise, you are constantly trading one item for another to get an aircraft that is best for a mission.

If you want an airplane that is optimized for longer range and more payload (for the same gross weight), go with a smaller engine with better fuel burn, same if you want to have it meet LSA specs. You can still have fun with aerobatics/dogfighting as proven with the prototype.

A larger engine will give you a higher rate of climb, about 1 more sustained 'G' in a turn, and a modest increase in speed, but you do that at the expense of payload, stall speed, and fuel burn.

Chris, realistically the O-200 will have similar performance characteristics as the Corvair.

[danweseman]

HI Guys
I'm in process of writing new FAQs to help cover this better.
in general be cautious when looking a engine manufacture's weight and power numbers.
as far as LSA concerns with heavier engines ,it comes down to useful load. a panther LS with a 0-320 may be over 800 lbs. empty. with a 1115 gross weight to maintain LSA stall speed this leaves 315 lbs. for pilot and fuel. for a 180 lb. pilot this would be fine, for a 230 lb. pilot he could only carry 14 gal of fuel ,which is about 1 hr. plus reserve with a 0-320.
from structural POV for the Panther LS you can carry 1050lbs and ADD the 160 lbs. of fuel for a gross of 1210 (about 410 lbs. of payload) and be within design limits and margins
(note this will not make the LSA stall speed)
For the Panther Sport you can go 1150 and add fuel up to 1210 lbs. We may at some point go to a 1250 max gross for the sport models after testing.
Hope this helps.

Dan the 175 lbs. number for a UL 350 is not realistic. I love the UL and we had one in our shop for about 6 months. I think they will work great but plan on it being about the same weight as your Corvair with about 15-20 more HP.

[PlaneDan]

Anybody considering the UL Power 350iS ? 130 HP at 175 pounds. I know the Lyc 0320 is highly available and relatively in-expensive, but if you really care about power and weight, maybe you should give it a look. Also, it is sold by SPA, so you should be able to get good support.

If I can sell my Corvair, that is what I am going to do.

Merry Christmas to all Panther builders and Enthusiasts.

[Sacpilot]

Yeah, I was thinking Lycon high compression o-200 with 9:1 pistons/cylinders. As I have already built an o-200 for my Zenuth that just sold. Only about $2k to do it. Would kick the o-200 up to 110-115 hp as per Lycon. Could also put a c-85 crank in to increase torque further. Could run with a true 110-115 dyno without appreciable wear on engine or high rpms, and you get a solid small engine like corvair for those who like aviation engines. Not better then Corvair, just different, for the WW fans.....

Paul, I do not care about LSA, and would do an o-320 in a heartbeat, but I thought gross was a hard number. Don't want to exceed gross or have to add rear ballast to offset for w and b. I am 240 lbs without belt and shoes, and I want to be able to carry more then 10 gallons of gas without exceeding the gross for aerobatics. Please clarify the o-320 comment

[at7000ft]

It is not that it is too heavy for the LSA wing, but too heavy if you want to fly it as an LSA. There would not be much useable load left with the 1115 gross weight to keep in the stall speed. If you want to fly it with a medical and standard EAB there is more of a margin.

Correct, but if the FAA removes the 3rd class medical requirement it won't matter.

[psalter]

It is not that it is too heavy for the LSA wing, but too heavy if you want to fly it as an LSA. There would not be much useable load left with the 1115 gross weight to keep in the stall speed. If you want to fly it with a medical and standard EAB there is more of a margin.

[Sacpilot]

My understanding was that the 0-320 was too heavy for the LSA wing. I assume you mean you are going o-320 with sport wing.

[Renegade007]

I think as Dan weighted everything the AE verison with the Christian Eagle system is slightly heavier than the 208 pound std IO-233.

doc