182 STOL driver wrote:

Emory Bored wrote:An early 182 is not an 1100 pound useful airplane. More like 900 and some change. A Mooney M20C can do that.

EB

N5502B 1515 Empty Weight now = 1035 useful .I do have set of wings with Wing-x(Flint tip tanks off 206) good for another +300 lbs.Yes it can run on mogas .P.S. I have set of digital scales for Weight &Balance-and
computer program -all certified and calibrated ever other year.

Bill, Is that the number reached after a pretty radical strip down, or with an intact interior? Either way it's really an academic exercise though. You just can't expect a Mooney to do the full monty over against the 182. The Cessna is a heavy hitter in so many categories while the Mooney excels primarily in the speed/economy race. A 182 would be my 1st choice but hardly my dream airplane. There isn't just one dream.

EB

I'm not sure what my dream plane is; something with the capabilities of a 180 that is an experimental and has a little more style.

Your probly right Z. I don't put as much weight on a new plane as others but you do have a point.

Think this 195 would be about right...

My looks into wing extensions for my '54 skywagon will put the useable load at more than 1300 pounds and it does have the MoGas STC and 150 MPH over the ground and I just like it! Pretty sweet. I assume, without checking, that this would be close to the same for 182's if you like nose wheels. As I understand it, the only 235HP Maule that can run MoGas is the O540C model. I think the C motors were used sometime in the '80s.
I am diggin the 180 and the wing extensions option is WAY high on my wishlist! I know after the ~$100+ per hour that the 206 was eating while me and my dog flew around was kinda painful, this MoGas thing is good.
As an aside, from an hourly guy in the oil industry, it looks like the big supply of light sweet oil from the Bakken fields should keep us in relatively cheap gasoline for a good long while.

I've always had a problem understanding how wingtip extensions can increase max gross. Doesn't it actually make the stress on the wing past the strut attach point greater?

So, what is the point of a max gross weight? Is it to prevent operators from exceeding practical performance limits? Or is it to protect the structural integrity of the airframe?

Fuel must be carried there, thus less fuel in wing tanks, more weight in cabin.

As I understand it the wing extensions use an additional spar strap so there is some additional structural change. There was a Lycoming O435 powered Stinson in the Portland Craigs List for $15,500. It was in annual when I talked to the guy a while ago but otherwise sounds like a dog. It might be worth the time and money though...?

Phone number in the CL ad for that Stinson is 503-701-7590.

Zzz wrote:I've always had a problem understanding how wingtip extensions can increase max gross. Doesn't it actually make the stress on the wing past the strut attach point greater?

So, what is the point of a max gross weight? Is it to prevent operators from exceeding practical performance limits? Or is it to protect the structural integrity of the airframe?

Seems to me that the specific loading on the wing would be lower with extensions - but yes you are right - the lift struts need to take more lift overall, and so do their attach points. That would also mean more compression on the fuselage.

In the Bearhawk, you are able to take off and fly at 2700lbs (if you're careful of course) but landing maximum gross is 2500lbs. That is dictated by the extension of the landing gear at that weight, and the oleo springs which are compressed - at 2700lbs the springs have almost no room left to compress, so takeoff on a smooth surface is possible, but landing would put the fuselage structure at risk if you bottomed out the undercarriage. It would seem that the wings are not the limiting factor in that case? But I understand the wings are certainly the limiting factor in terms of G-forces, so there must be some penalty there??

To that point, I've wondered what wing extensions would do for a Bearhawk's takeoff performance. While it's all in pieces on the table, it seems the easiest time to fit extensions anyway.

Sorry about the thread creep Whee.

108- Stinsons w/ 180 Franklin would perform better, 80 octane, same speed. 220 Franklin might go faster, climb even better, 100 octane.

flyingzebra wrote:Phone number in the CL ad for that Stinson is 503-701-7590.

For what it's worth that Stinson seems to have been on CL the last few years.

Battson wrote:To that point, I've wondered what wing extensions would do for a Bearhawk's takeoff performance. While it's all in pieces on the table, it seems the easiest time to fit extensions anyway.

I think that Mark/Budd/Bob B address that question in an FAQ I read recently. They basically say "not recommended."

Whee,

Let me know when you want to go and we will get together.

Regarding wing extensions and speed.....longer wings are generally considered to produce more drag. However, these wing x extensions would seem to me to change the cessna wing to more of a "high aspect" configuration which is supposed to be faster. So what do they do to your cruise speed (same rpm/mp settings please)?

What about a M6/235? The O-540-B4B5 is approved for mogas and can be installed on the M6. Looking at the numbers is seems like they have about ~1000lbs useful and that is all an early 182 has.

Sounds like a good choice....

I think you would get even more useful out of an O-360, for only a little less horsepower (180hp vs 235hp). So it really all depends how much grunt you want v.s. how much you want to haul?

Just my 2c, it seems a shame to haul that big -540 around all the time to only get 235hp (the "Lazy Six"). They are comfortably a 250hp-260hp engine. They are regularly boosted up to 300hp or even 330hp on experimentals just with higher compression cylinders, so they are still very under-worked at 250hp and will be very reliable. And of course you're still burning Mogas (although I am not sure how the certification works out there).

Battson wrote:I think you would get even more useful out of an O-360, for only a little less horsepower (180hp vs 235hp). So it really all depends how much grunt you want v.s. how much you want to haul?

We recently had a discussion that very thing recent, regarding an M5-180.

viewtopic.php?f=9&t=11590

I think the consensus was that it all depends on how heavy you run. If you're going to fly solo, the O-360 would suffice, but put any family meat or gear in there and you need the ponies of the 540.

Get the 220-TC, it packs 1100 pounds and makes 220 ponies to 20,000 feet. Good site if you don't already have it: http://www.risingup.com/planespecs/

I think Lyc. O-360's must be derated(170 HP) w/ lower compression pistons to burn MOGAS.

"Useful load" figures are not really the whole story. If I could get the paperwork approved, I could, modify a c150 gross to about 2100# to come up with a useful load of1,000-- but it would need an awful lot of real estate to get airborne & would barely get out of it's own way. Better to look at power loading (power/weight) and wing loading (wing area to weight) ratios, if you wanna get an idea of performance.

Zzz wrote:I've always had a problem understanding how wingtip extensions can increase max gross. Doesn't it actually make the stress on the wing past the strut attach point greater?

So, what is the point of a max gross weight? Is it to prevent operators from exceeding practical performance limits? Or is it to protect the structural integrity of the airframe?

In fact, max Gross Weight of a particular aircraft is rarely a wing or fuselage structural issue. There are lots of things that may limit the max GW. Consider that at least one current production airplane's max gross weight is limited by NOISE on takeoff. If an airplane can't climb at a steep gradient, it'll fly close to the noise monitors off the end of the runway. Too much noise, and either the prop has to be dialed back, or the GW limited to permit higher initial rate of climb.

Landing gear and attach points are often limiting factors in max gross weight. Remember, these things have to pass a drop test, on the off chance that a pilot might actually land kinda hard one day.

Climb performance, Takeoff Performance and even landing performance can limit gross weight.

For the most part, manufacturers seriously overbuild the wing structures, the fuselage structures and the tails of airplanes. These fail, someone is going to die and more than likely sue the company.

The new noise regulations in the certification process are causing some fits for manufacturers, and may in fact end up as the single primary limiter of aircraft and components. Witness the Aviat model A-1C....when they upped the GW to 2200, they had to turn the prop rpm back from 2700 to 2600, to pass the flyover noise tests.

The PA 18 ended production as a 1750 lb GW airplane, but Wipaire was able to certificate the airplane at 2000 pounds by adding a couple of small cap strips to the wing spars and a tube or two to the fuselage in the landing gear area. Pretty minor changes structurally, considering a well over 10 % increase in GW. THe stall speed, however, changed from 42 to 53, at least on the early conversions.

Stall speed can govern GW as well, at least on faster single engine airplanes. Certification rules require that single engine airplanes stall at 61 knots or less. By the way, that should tell you something about the importance of slowing down if you're about to land after an engine failure.....

The TBM 850 had plenty of power and plenty of performance, but they needed to increase the GW to offer more loading flexibility. The limiting factor was that the airplane stalled right at 61 kts, and that was what was limiting the GW. Increase the weight, and the stall speed increases....

They petitioned the FAA to allow them to exceed the 61 knot stall speed by installing and demonstrating the crashworthiness of their new 26 G seats. The FAA bought off on it, and they increased the GW of the TBM by a couple hundred pounds, which was ALL useful load.

Etc. Lots of similar examples where the GW was limited due to performance rather than structures.


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