Larry Mednick
Forum Replies Created
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I think the real trick is to either find a wall to block wind from behind or make sure the wing has “some” positive AOA. I have seen trikes flip over while tied down when the nose of the wing is down and wind is coming from behind. Our wings DO NOT LIKE WIND FROM BEHIND!
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With a naturally aspirated engine, the horsepower reduces, very similarly to the reduction of resistance on the propeller. Meaning if you’re getting 5500 RPM at sea level you can expect to get very close, although it will be slightly lower, RPM at high altitude at WOT.
With an electric motor, the RPM is limited by the KV, or RPM per volt. So the reduction in drag on the prop at high altitude will have no bearing on the RPM. And sure, the amp draw will reduce significantly at high altitude, but it will simulate the same effect as a naturally aspirated motor at high altitude.
Much like a turbo charged engine you MUST either repitch the prop for high altitude or have a variable pitch prop to be able to even take advantage of the motor keeping its HP at high altitude.
So to sum in all up, an electric motor with a fixed pitch prop will give you a very similar reduction of thrust, the higher you go, to a regular combustion engine without a turbo.
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Hey Roger, the yarn should work. Have a look.
slipping turns
https://youtu.be/evPA1h6hXfkslipping turns
https://youtu.be/evPA1h6hXfk -
Ted, I assume you are referring to Reb’s fatal accident. In that case the student’s attempt to exit the maneuver was attempted just seconds before impact. I am pretty sure Reb was planning to pull out of the spiral at the last moment when the student in the front seat beat him to the punch by pushing the bar out.
What was clear from the NTSB report and the recorded dialogue, is the student was very scared and was even yelling profanities, the instructor was cool as a cucumber and enjoying the maneuver and the student wanted the spiral to stop and seemed helpless.
The moral of this story is if your student is scared for whatever reason they can lock up your controls and if the instructor doesn’t have enough time to get the aircraft away from the student, bad things will happen.
Reb’s last word was “IN” and I assume the student was pushing out at that last moment before impact. I believe if they had more time and altitude all could have been avoided.
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Was hoping for some more comments. But here is my own personal view. In triking I believe well over 80% of fatalities are spiral dive related. Sure loss of power and weather account for many, but not like spiral. Spiral can happen any time. Any time the pilot makes a bank steeper than their air speed allows. Sometimes the pilot does not properly coordinate the turn and what I am coming to the conclusion now is there are 2 types of spirals. One where adding power and or pushing the bar forward will not only not stall the low wing, but will actually reduce or eliminate the descent. I believe many trike pilots are using poor technique which works on these “mild” spirals. And then there is a breaking point with a little more bank and a little more nose down attitude where those rules instantly change and throttle or bar out can stall the low wing, but more importantly tighten the spiral and increase descent.
In summary if you are not sure of what I am talking about and you fly trikes, take some time to familiarize yourself with proper and improper spiral dive recovery.
spiral training
https://youtu.be/KPhIc97z_4gspiral training
https://youtu.be/KPhIc97z_4g -
Yes that’s the only trike mid air fatality I am aware of. The HB was irrelevant since the keel, the leading edge, the keel pocket, the wing strut all broke as well as the 5/16” bolt the safety cable went to.
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It is probably a “J” type sender and if that’s the case call 1-800-LA—ROTAX. They have them.
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Hey Roger, on the point of the wind pushing you after touchdown, even in a 15 mph tail wind the wind will not be pushing you until your trike slows below 15 MPH on the runway. The much bigger effect is if you touch Down at 40 MPH, now you are touching at 55 MPH. If we have brakes, then we generally rely on stopping power and not drag to bring us to a stop. Neutralizing the wing will allow your brakes to do their job. Not finishing a flare will allow the brakes to start doing their job earlier as well. So I agree neutralizing the bar is important for stopping short, but not because the wind is pushing on the top of the wing.
Short Field Demo
https://youtu.be/yQ29hOZU55oShort Field Demo
https://youtu.be/yQ29hOZU55o -
A few tips:
1) Treat X wind landings like any other landing. The only difference is you stay in a crab and touch down crabbed.
2) you can add a touch of power in the flare to soften the touch. A soft touch is the key when on hard surface. In grass don’t even worry about it.
3) touch down on the “trailing” rear wheel. If the wind is coming from the right, touch on the right tire first. The right tire will slide, the left tire will bite.
Sliding for a 1/2 second will gently align the nose. Dropping the trike in a crab will make the tires bite on hard surface. Grass or dirt will ensure the tires slide.
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Hi Ted, I haven’t looked at the NTSB report on that one, but I have the whole video of what happened. Definitely a spiral, definitely used full power to try and exit. His trike responded 100% correct to the pilot input. Very sad…
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The spiral is a safe and effective maneuver. I don’t know why any instructor would avoid teaching it to students. But you have the real life reality of the situation.
REAL LIFE SPIRAL
https://youtu.be/G75bt1gL8FAREAL LIFE SPIRAL
https://youtu.be/G75bt1gL8FA -
The 2nd bird strike similar to the Sky Catcher was an RV4. Both cases required hot landings with lots of rudder. The 3rd one was Craig Ewing in his REVO. No BRS and it was fatal.
The wing landed about 1/2 mile away from the carriage. The carriage apparently free falls inverted and so the seat belt was undone and the pilot was found a few hundred feet away. If he unbuckled the seat belt and bailed, I’m sure he could have pulled a chute. The wing floated down very gently and landed in high soft grass. allowing us to see the damage and the impact zone that happened in the air. Unfortunately no DNA on the wing but the impact zone was so clear and the wing strut hit the engine when it turned 90 degrees to the carriage before separation. The 4130 mast was also twisted 45 degrees. The leading edge was also broken and the HB torn in half (before we had CNC HBs)
And unfortunately this was in IMC conditions and the pilot was on 2 different “no fly drugs” with a history of accidents in all types of aircraft with FAA violations. So the NTSB report reads inaccurate as best the evidence showed a mid air. No telling how fast he was going or what he hit. I have all the photos. It was fairly obvious to me and others what happened.
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I have 3 friends that have had mid-airs with birds including my father. My dad was in a Cessna Sky Catcher and a vulture pushed his leading edge all the way back to the spar with over $10,000 damage. The impact knocked his students headset off his head. Because of the way a trike wing is attached, it cannot withstand much of a leading edge impact. The structure is simply not designed to take a load in that direction. We did a test on a fairly standard hang block and found it to break at 2500 foot pounds. That may sound strong, but 15 feet out from the HB that means a force of 166lbs will snap the HB. And that sounds scarier, now multiply a 6lb bird getting hit at 60 MPH and you exceed that number by quite a margin. I forget the math used to calculate that, but your wing will probably not survive a large bird strike.
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Almost anytime you can get above the lower cloud layer or sometimes there is a haze layer, you can expect smooth air above. If there are mountains, then that is a whole other story and you must be upwind of the obstruction. But let’s not forget, we have to land in these conditions. So if you are uncomfortable in the air, you will probably be very out of your comfort zone to land. And anything upwind of your landing zone can make it dangerous and impossible to land safely depending on your skill, the wind speed and the size and proximity of the obstacles. So that is always my main concern with loss of control from weather. Let’s face it if you let go of the controls the trike would enter a spiral dive within several seconds and then you would have about a minute for every 1000’ to recover. There is simply almost never anything to crash into up in the sky and the trike will not flip over from turbulence. Only a rotor has the ability to flip an aircraft.
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Flying anytime you are pushing your own personal envelope is a recipe for trouble. Some new pilots should not fly past 8:30 in the morning. Some advanced pilots should not fly in over 20 MPH surface winds. Whatever your skill level, it is important to build skill while staying within your safety envelope. And this takes a lot of will power and good decision making. I tell my students that they should not do a Xcountry until they know they can handle substantial wind and turbulence. The reason is things can change when you fly away from the airport and return 2 hours later. CONTROL YOUR ENVIRONMENT until you know you can handle whatever weather might develop. And the way to do that is shoot touch N go’s every 5 min in the pattern while the weather is changing in the mornings. When your last landing was challenging, stop and put the trike away.
If you want to fast track the learning, go up with an instructor in rough mid day conditions and get your technique right and effective with an expert in the back seat.