Ice Pilots

thehaze · January 03, 2013, 03:53:56 PM

Can't get anything by you...

pmackenzie · January 03, 2013, 06:59:07 PM

Quote from: flying saucer on January 03, 2013, 12:06:04 AM
Many planes pitch up under power, especially flying upwind, this is normal. I'm surprised it doesn't happen with your Sundowner?

Once a plane has left the ground wind direction is irrelevant to how it flies. It only affects ground speed, and hence our perception of its airspeed.

flying saucer · January 04, 2013, 02:40:22 PM

I would agree, however I have noticed my models tend to climb slightly when flying upwind at a given throttle setting, when flying downwind they fly level or lose altitude slightly. Although most of my planes don't fly "perfect", I have become used to utilizing the sticks to fly around bad habits and strange tendencies.

piker · January 04, 2013, 05:08:43 PM

Oh man, I had this exact same discussion with a fellow flyer in 1995!

I was of the same opinion as Jeff and I was too determined to accept anything else because I Knew (and still know) I could see a difference. Here's my current opinion on the subject:

I agree that in theory (and reality) the aircraft knows nothing about wind (besides gusts) when in the moving mass of air. What I think is causing the effect that we are talking about is the fact that we, the pilots are standing on the ground and therefore that is our frame of reference. I believe that when flying into a head wind, we observe the craft slowing down and tend to hold a bit more power to try to maintain a comfortable ground speed. When the plane is flying down wind, we subconciously tend to want to slow the plane a bit and will hold less power. This is my only explanation for what I observe. Oh, and when turning from one wind direction to another, we want to see a nice smooth radius, not one where the plane is drifting downwind (as it would while moving with the air mass), so we do the same thing by compensating with power, whether we know it or not.

What do you guys think of my pet theory?

Robert

pmackenzie · January 04, 2013, 07:52:39 PM

Sounds about right to me.

Wingnutz · January 06, 2013, 01:06:59 PM

Have enjoyed the various twists and turns this thread has taken so until my new knee lets me get back to flying, thought I'd post on the joys of being an Ice Pilot...
In response to Andy's post showing a mechanism for pushing the ski into a positive AofA without actually going vertical once the model lifts off, I re-installed the skis on my trusty Apprentice and have included pics of the wheel collars and spring arrangement used to achieve the above. My variation took several sessions to evolve but seems to work well with the Apprentice's three pound weight.
Also some photos of Ice Pilot Ken Ross flying his truly all-weather F-18 pusher in February 2012...yes, there were a few days last winter with snow! These were taken with my dumb phone last Feb so hardly photo award quality! Get out there...enjoy winter!

Ededge2002 · January 06, 2013, 01:32:15 PM

That method of ski positioning is amazing. Very well thought out and minimum parts. Nice show I must say.

pmackenzie · January 06, 2013, 02:38:09 PM

If you run the end of the wire through a tube glued to the ski it will both hold the tips up and also stop them from going too high.
This is on my brothers old Easybuilt Turbo Porter.

How old? First flew at Miliken Park, brushed 550 and 6 cell NiMh.
Very efficient setup that would cruise around for 15 minutes.
A lot of fun to fly off fresh snow, just skimming it so only the tails of the skis are touching.

Pat MacKenzie

Wingnutz · January 06, 2013, 11:36:18 PM

Very neat idea Pat! Gotta try that this winter!

Andy Hoffer · January 06, 2013, 11:52:32 PM

Today (late afternoon) was very interesting for ski "flying", and very different from my earlier post. The snow is now saturated, wet and heavy, as opposed to the nice light fluffy stuff of just a day ago. I could taxi fine, but as soon as I started my takeoff run, the ski created a bow wave at the tip, effectively providing a packed snow chock in front of each ski which resulted in a nose over. No amount of finesse could get the plane airborne.

Re control of ski angle of attack after takeoff, I am intrigued by the elegance of the designs used by Bill and Pat. I had used the approach evident in most of the full scale ski planes I found by Googling "ski plane images", all of which show bungees attached to the ski tips and travel-limiting guy wires on the ski tails. The original DuBro skis I used had torsion springs attached to the struts, but I thought rubber bands and string would achieve the desired performance with less weight.

Now we just have to wait for some more real snow.

Andy Hoffer

sihinch · January 07, 2013, 08:20:45 AM

Floats worked great!

Bobmic · January 07, 2013, 08:21:49 AM

Quote from: pmackenzie on January 06, 2013, 02:38:09 PM
If you run the end of the wire through a tube glued to the ski it will both hold the tips up and also stop them from going too high.

Pat MacKenzie

Hi Pat,

I understand the section of the wire that goes into the tube but how do you attache the spring wire to the landing gear axle. The Du-Bro method wraps around the axle and the spring is only pushing the ski while a mechanical stop is used to limit the travel down lower than parallel to the wing.

Now I have a second question:
I was at AJ on Saturday and bought a set of skis for my Toledo Special, he also had plastic floats that should fit this plane and do not cost like a new one as the H9 (they were something like $50 less then double the price of the skis).
I am not sure what is involved in taking off and landing of water etc. but what do you guys think - should I keep the skis or swap them for the floats as I am sure they can also work on snow even if they will not look as nice or efficient...

Thank you

Bobmic · January 07, 2013, 08:31:33 AM

Hey Simon, Nice plane !
Next time you have to put more effort in the photos and lay on the ground level with the plane as Andy does - we will have better appreciation on the scale and beauty of your plane.

piker · January 07, 2013, 09:55:58 AM

Hey guys. Fair weather flyer here (a feel a little reluctant to post in the Ice Pilots thread

)

But, like they say... opinions are like A$$H*les... everyone's got one

First, I don't think most people here would get the Milikan Park time frame reference, Pat. To clarify, I think you're talking 1990ish... right?

And in my very humble opinion, Bobby, floats are a good way to go, especially considering what Andy was talking about. My opinion is that ski's are great (and cool) when the snow conditions are ideal. Soft and fluffy, but not too deep with the fluffy stuff. The ski's have a pretty modest contact patch for the weight of the plane (unless we're talking about a light foamy. Floats distribute the load better, have a large bow to "ski" up onto the snow, have a longer bow to prevent nose over, and generally a wider stance for lateral stability. And of course, then you'd be set for float flying in the Spring

Andy Hoffer · January 07, 2013, 11:31:14 AM

Quote from: piker on January 07, 2013, 09:55:58 AM
Hey guys. Fair weather flyer here (a feel a little reluctant to post in the Ice Pilots thread )

But, like they say... opinions are like A$$H*les... everyone's got one

First, I don't think most people here would get the Milikan Park time frame reference, Pat. To clarify, I think you're talking 1990ish... right?

And in my very humble opinion, Bobby, floats are a good way to go, especially considering what Andy was talking about. My opinion is that ski's are great (and cool) when the snow conditions are ideal. Soft and fluffy, but not too deep with the fluffy stuff. The ski's have a pretty modest contact patch for the weight of the plane (unless we're talking about a light foamy. Floats distribute the load better, have a large bow to "ski" up onto the snow, have a longer bow to prevent nose over, and generally a wider stance for lateral stability. And of course, then you'd be set for float flying in the Spring

Especially when the snow melts at TEMAC !!

ANdy