Thread: tail strikes

Originally Posted by runtoeat

... My usual CTSW final approach in light wind is with 15 degrees flaps and throttle totally backed off. Once in a while I need to add in a squirt of throttle during short final. This prodedure doesn't work with the CTLS. I start my appraoch with some throttle and need to be ready to add more on final due to higher sink rate of the heavier CTLS...

a power off approach will work with the ls as well as the sw. the difference is judgment. think of the ls's "higher" sink rate as a result of your speed, configuration and pitch attitude as opposed to it being heavier. think of the sink rate control as an energy management problem.

in a power off approach if your sink rate is too high you only have 2 choices. the easy choice is to raise the nose, increasing aoa resulting in more lift and less sink. if raising the nose results in more sink you are behind the power curve or too slow.

if you learn power off in the sw with 30 degrees you will improve your energy management skills.

Charlie Tango, I see your point. 30 degrees of flaps on SW can result in pretty sudden sink rates if the pitch and speed and height above the deck isn't mangaged - very similar to sink rate of LS at zero or 15 flaps. I get a little smile on my face when I recall thinking that flying light sport planes was going to be simple!

Dick

Originally Posted by runtoeat

.. I get a little smile on my face when I recall thinking that flying light sport planes was going to be simple! ...

this is a coin with 2 sides. in the early stages it is evident that a ct is more challenging to land in gusty x-wind conditions and the result is a demand that you become more proficient. the result in becoming more proficient in a ct is a lot of pilot enjoyment.

every niche has it's own rewards and drawbacks. the ct allows me to experience the micro-meteorology while remaining fuel efficient and a useful x-country plane.

having a close relationship with the micro-meteorology is a 2-sided coin as well. the ct has made me a better pilot and put me more in touch with mountain, desert, and coastal conditions.

In my defense, this was at gross on a hot day (1PM in Dallas, June) where the air just over the runway is probably 120F. The ground effect you're used to in the winter/spring/fall isn't there. If I had too much speed I would have bounced several feet into the air, but I didn't. My rule of thumb is to bring an extra 5 kts at mid-day, especially on asphalt.

Did I mention "simulated emergency", hence the -6 flaps (power failure or motor burn-out) return-to-field at idle?

All I can say is that... one day the tail will strike, and the lightweight construction of the ventral fin will not stand much abuse.

After one incident the damage was as shown in the first photo. The repair beefed up the lower corner of the ventral fin and added a replaceable tail skid. Of course since the skid was added, no more tail strikes. The cost? About $150. The ventral fin is not a structural component.

Incidentally, the strike occurred while doing practice zero flap landings = high nose attitude on approach. Fly the aircraft on while being conscious of your attitude. The only thing that suffers then is your brakes... but if you have the Matco replacements... no problem.

What do you expect for $130 grand?

If it happens, they ought to protect against it.

Waggles, that is a nasty looking runway rash but the modification is a work of art. The skid is well done and might be something that FD should consider incorporating. Rough calculation of adding 2 pounds 96" reward (??) indicates shift rearward of CG less than .2" (to 15.23") on CTLS I am flying. You are right, sooner or later and after enough hours, good odds of a strike happening.

My tail "skid" has a little paint missing and maybe a tiny bit of glass abraded off. My guess is that we just scraped it during a landing or over-rotated with the CG aft (can be easy to do). It's not damaged at all like the other photos, just a little rough. It's entirely possible that it's gotten roughed up in the hangar, partiaularly at our local A&Ps.

I agree that the ventral fin is not a structural part. It is probably a good place to locate the ELT antenna, VOR antenna (if you really need to have a VOR) or second COM antenna.

Doug

For those who might be considering a similar mod, the weight added to the ventral fin was less than 1 lb (480 grms) and in my own case this was about a pencil thickness on the CofG graph. It was such a small change I considered it a "non-event" for all practical purposes.
The skid itself is made from 1/2" (13mm) high density polyproplene, attached with two 5mm diam bolts that screw into a 5mm thick alloy plate at each bolt location.

I molded some body putty on the end of the vertical skid. I wold caution against a "hard point" fix as you want to prevent shock damage to the tail structure. That is why airliners have skids with shocks. I think the putty will absorb the shock better than a metal surface.