PA1195, Gary,

I don't have enough math and physics knowledge to understand your triangulation, but think the wide gear helped the CallAir a lot. Nothing to do with ground loop, but does the ribs in all the control surfaces give it the fine control feel? If you have flown helicopters it is like the difference between having hydraulics or not. Pawnee is like loss of hydraulics all the time. I always thought that was the flat control surfaces in Pawnee. Really hard on the back to be pulling on the stick so hard with a load. Also maybe why A9, both A and B models, were considered so dangerous. The insurance thing with number in service compared to number of fatalities may have something to do with that reputation. I loved the airplane, yes, even with a load. Wouldn't haul as much as the identical wing area Pawnee, but hauled it like a sports car instead of a Mack truck.

Jim

The only tri gear aircraft I've flown since I started flying tail draggers, was a little Titan Tornado. With a sub 20' wing span, helicopter like over the nose viz, and though I hate to say it, the tri gear, I never felt more confident in making road landings. It was stupidly easy, no real skill involved. It made me re-realize how some tri gear pilots really have to wake their feet up when they go over to the dark side.

courierguy wrote:The only tri gear aircraft I've flown since I started flying tail draggers, was a little Titan Tornado. With a sub 20' wing span, helicopter like over the nose viz, and though I hate to say it, the tri gear, I never felt more confident in making road landings. It was stupidly easy, no real skill involved. It made me re-realize how some tri gear pilots really have to wake their feet up when they go over to the dark side.

Funny,
had the same experience a couple years ago when i did my biannual flight review in the 172 i got my license in 15 years before while my plane was getting its annual finished. After over 1000 hours of flying a tailwheel, landing a trigear was very anticlimactic, only issue was getting used to how much shorter it sat, kind of dropped it the last few inches till i got recalibrated.

I read the whole 7 pages of this, wow! There is one class of groundloops that i didn't see mentioned and that is those caused by mechanical issue. A stuck brake, a frozen wheel, a flat tire or in my case a broken tail wheel bracket.
For the OP, I think the Stinson is maybe one of the most forgiving. it may not be all that much better about the loop but if the gear is working like it should it is so soft and doesn't toss you back up so it helps to not get bounding or porpoising that can lead into a ground loop.
Fun discussion, lots of food for thought.
Lets all strive to have a happy and safe new year.
Shane

shorton wrote:I read the whole 7 pages of this, wow! There is one class of groundloops that i didn't see mentioned and that is those caused by mechanical issue. A stuck brake, a frozen wheel, a flat tire or in my case a broken tail wheel bracket.
Shane

Good catch! I purchased a really sweet 1975 Grumman Traveler (which uses a castering nose wheel with differential braking for steering). It had been "ground looped" twice – and properly repaired by one of the Grumman Guru shops both times. In both "ground loop" incidents, a brake failed while taxiing – once veering into a Mooney parked in a tie-down spot, and once into a hangar. One was caused by a ruptured brake line (improperly secured fitting), and the other was caused by a slow leak that eventually allowed air into the system when the brake fluid reservoir ran dry. So it does happen!

Needless to say, pre-flight inspection of the brakes on that plane became a high priority item for me, including checking the brake fluid reservoir. It wasn't easy, because of the tight-fitting wheel pants, but that's what inspection mirrors (and fingers to feel for "wet" fittings) are for...

Agreed on mechanical issues associated with ground loops. Happened to me in a Super Cub in very cold weather. Not my airplane, it had been put on the gear, then parked outside in very cold weather. Airplane was equipped with North River brake boosters. Owner complained to mechanics after he taxiied it to parking that left brake was mushy. Mechanic topped off that reservoir.....at -20 or so.

We took off, did some air work to warm up. Plane had a great heater, which coincidentally blew right on the left brake reservoir. Came back to airport, and did stop and go. On takeoff, I noticed that the left tire slowed and stopped fairly quickly after takeoff.....hmmm.

Next landing, plane swerved hard left, left brake was essentially fully applied due to heating of the reservoir.....North River boosters are not vented. Result wasn't pretty, but we were along as passengers at that point.

FAA authorized mechanics to move plane off runway....they moved it into their hangar. When FAA Inspectors came to examine the plane the next day, left wheel turned nicely......duh. So, I got a 709 ride out of the deal.

The lesson: Never, ever fly an airplane with non vented brake boosters. My airplanes since have had vented boosters.....a MUCH better program.

MTV

But the FAA looked good, a operator, mechanic, or pilot was blamed, and somebody in the office got to deal with the rest.

A friend had his tailwheel spring broke in flight on his Christen Eagle II. He wasn't aware of it and ground looped to the right upon touchdown. No damage, just a dirty airplane which is amazing considering how low the bottom wing is to the ground.

Touching down as slow as possible, in low ground effect, makes a gear and wingtip difference at least. Wooden prop helps, but they are mostly gone.