Numb Thumbs !!

[apprentice1]

Just got in from flying four 12-minute pac's with the Apprentice. With the exception of a scary moment on flight 2 all went well. But I did have a new experience. The WX was clear, calm winds and 35 F. I was on down wind for landing when my left thumb went completely numb ! I couldn't feel a thing, absolutely no physical connect between my brain and my thumb. It caused me to over control the plane that resulted in a very ugly base leg and final, I almost lost it. I went around, got it up to about 100', flew in circles for a minute and then came in for landing. I've only been flying a couple of years but have never had that happen before!

[AV8TER65]

What do you do for a real job apprentice? I am a Aircraft Structural Mechanic and have been for awhile now. I have the early signs of Carpul Tunnel where my hands and or fingers are starting to go numb. Just a thought, I hope you get to feeling better.

[apprentice1]

I'm a ground and simulator instructor for the Fairchild Metroliner (SA227) for a charter company in San Marcos, TX.

I have experienced that before why riding a cycle.

What city do you work in?

[WJCJR1]

Numb thumbs happen when you are doing little activity and your fingers are exposed to 35* weather and a little wind for almost an hour.

I had a horrible landing the other day too, first flight Sunday and it was 32* with a 9 mph wind, came to set-her down and no feel on the thumb. I ended up pulling WAY UP on the elevator and looked skyward with the plane, pulled the Apprentice back level but had to abort otherwise the front nose gear was going to be blasted into the ground. Did the same went around a lap and ended up landing by motor reduction of speed more than anything else.

Went back to the running truck and warmed my hands, put Seal Skins on and went back at it.

Apprentice1 what is the voltage rating on your battery before flight and after you pull it out after flying. YOU should be getting WAY more than 12 minute flights. My flights are lasting 23-36 minutes now, if I am trying to rip the wings off I get 23-24 minutes if taking it leisurely well over a half hour.

Please check your voltages, I am curious. The flight times I mention have voltage readings of 12.56V preflight and running down to 10.09V-10.15V postflight voltage. These numbers are very consistent and flight times predictable by the clock. If your pre/post numbers are far from these numbers we can do something to extend your flight times.

Wayne

[ATIS]

Lipos HATE the cold. A little trick I use in the winter is to get a little plastic insulated lunch box from Wally World in the fishing section and a package of the toe warmers. Put 2 of the toe warmers onto the inside of the lunch box and set a towel in the bottom. Stick your fully charged lipos in the box and take to the field. It will keep them warm and you will have near full power from the start. On really cold days if you dont do this the power will be down for the first few minutes of flying and then you will notice the power slowly increase as the lipo warms from use...on really cold days it wont warm at all and the power will be way down.

[WJCJR1]

Yeah I usually leave the heater blasting in the truck for a bit then the start it every hour to keep the batteries warm. Kind of an expensive way to heat though, so I will look at that method you mention or maybe even one of those hot/cold packs that hold heat forever; heat these packs in mocrowave.

Wayne

[apprentice1]

Numb thumbs happen when you are doing little activity and your fingers are exposed to 35* weather and a little wind for almost an hour.

I had a horrible landing the other day too, first flight Sunday and it was 32* with a 9 mph wind, came to set-her down and no feel on the thumb. I ended up pulling WAY UP on the elevator and looked skyward with the plane, pulled the Apprentice back level but had to abort otherwise the front nose gear was going to be blasted into the ground. Did the same went around a lap and ended up landing by motor reduction of speed more than anything else.

Went back to the running truck and warmed my hands, put Seal Skins on and went back at it.

Apprentice1 what is the voltage rating on your battery before flight and after you pull it out after flying. YOU should be getting WAY more than 12 minute flights. My flights are lasting 23-36 minutes now, if I am trying to rip the wings off I get 23-24 minutes if taking it leisurely well over a half hour.

Please check your voltages, I am curious. The flight times I mention have voltage readings of 12.56V preflight and running down to 10.09V-10.15V postflight voltage. These numbers are very consistent and flight times predictable by the clock. If your pre/post numbers are far from these numbers we can do something to extend your flight times.

Wayne


Wow, what a coincidence that happen to both of us on the same morning!

I have two batts for the Apprentice, the 15C 3200Mah and a 20C 3200Mah. The volts where 12.58 at start and 11.6 at the end. I don't know if it's me, but the plane gets really sluggish at about the 12 to 15 minutes.

[AV8TER65]

If your asking me apprentice, i'm currently in Japan at Naval Air Field Atsugi.

We have a Japanese flyer that is a big electric guy and now i know why he brings his cooler with him full of batteries. He has like 10 he brings on any given Sunday

[WJCJR1]

Apprentice1 if your Post-Flight voltage is 11.6 you have gobs of time left.

For the sluggishness, in increments add some weight to the tale, either right at the entry to the fuselage or like I do further back above the servo arms.

Well first check your COG. Mark where it is and move it back with the aid of installed weight by a 1/4inch. This should loosen up the plane, sounds real nose heavy to me and after 12-15 minutes the drop in voltage is spinning the prop less/rpm thus the nose is dipping and you are wasting power holding up the nose. If the 1/4 inch moving of the COG is not giving you a looser plane go back another 1/8th then another and so forth.

Do the above instruction and see how she flies. Be careful now do not get over zealous, a little too much tail weight you'll be flying a plopter, that's WJCJR1 for plane-helicopter. An aft heavy plane flies ferociously loose and makes for a white knuckle return to the airstrip.

Please report back if the COG change if you try improves your flight characteristics and flight length. You should be able to drop to 10.50V before she gets doggy.

Wayne

[apprentice1]

Thanks for the info, I'll give it a try!