Earthstar Forums

Why not bypass all the complications and expense of the electric stuff, put on a good HKS and simplify your flying by carrying a couple of gas cans?

Since Mark is not responding, I can offer only very rough estimates:


Soaring Gull



Hard data assumptions as published :



Stall Speed: 23 mph

Max L/D: 16



My rough Estimates:



Speed for Max L/D: 1.31 x 23 mph = 30 mph



Sink rate at Max L/D:

Convert everything to metric system

30 mph x 1.6 = 48 kph = 13.3 m/s



13.3 m/s divided by 16 = 0.83 m/s = 163 fpm sink rate @ 30 mph



Min Sink will be in the order of 140 fpm @ 34 mph



At 45 degrees wing inclination min sink rate will be in the order of 197
fpm @ 40 mph. With typical piloting imperfections, 220-240 fpm will be most
likely. A typical 500 fpm thermal will give you a positive climbing rate
of, say, 250 fpm




Notes: Sink rate and stall speed increases proportional to the square root
of the increase of (New higher Weight / Initial Weight) Where initial
weight is 550 lbs.



I do not advise to buy a Total Energy Variometer. They are very useful only
with high speed competition sailplanes. It will be a waste of money where
cruise speed is very close to thermalling speed. The kinetic energy
differential will be too little to confuse you on whether it is a real
thermal or a "joystick thermal".


The performance you will get will be very similar in min sink rate as the
SGS 1-26 buy your thermalling speed will be about 30% higher. I used to
thermal at about 34 mph with the 1-26. Under my assumptions, you would be
thermalling at about 40 mph. with larger circles.


Hope this helps you.

Wow. You guys are a great group.


Jaime: You told me what I wanted to hear... total energy was unnecessary. When looking at current varios they all specified using a Total Energy (TE) probe. When I flew gliders thirty years ago, connecting to the static line gave you a non TE vario. Will a modern, non-reservoir vario work properly in non TE mode?


Scot: You are right to say using gas cans would be much easier for me. I have already done that with 'conventional' aircraft. I loved flying long distances on multi day treks. But now I want slow, quiet and low vibration. If an egull does not work, I suppose I could do a reversion conversion to gas.


Mark: That's great news a cherry picker hoist will do the job! I believe that issue was the only potential show stopper remaining. I will email you at Thundergul in a few days to discuss next steps.


Thanks to all who responded.


--Ray

"Will a modern, non-reservoir vario work properly in non TE mode?"

I am sorry I can not answer that one. You will have to ask the experts on
varios.

Happy New Year

This is a great thread everyone.

Lots of useful info and helpful, even to an Odyssey driver.

Each plane is slightly different, as each builder may add a thing or two.
Go take your plane up with a sensitive VSI (vertical speed indicator), and look for minimum sink rate and the airspeed. do it at idle, then do it again with the engine shut down. Just beware once the prop stops, no amount of diving is going to spin it again, unlike a Cessna. Be sure your over a land able site like an airport. It gives the real numbers in case of engine stoppage. I haven’t checked it lately with my add-ons, but as I remember it was much closer to 10 :1 glide ratio, maybe better. Mark knows as the prototype was built and flown and had those numbers in his design. The Titan guys are kinda falling apart. Funny since they pirated the design from Mark.

Kess, I like the test procedure. I have always been amazed at how often a bit of real test data can destroy the most elaborate theoretical predictions.



Jaime, I did a little more digging into vario operation. I think I understand a bit more what to expect. Using TE probes automatically compensate for the change in density/pressure as the altitude increases. Replacing the TE probe with an ordinary static line will still give an instrument that would read accurately at sea level. As altitude increases the indicated value will gradually diverge from true, similar to the difference between indicated/calibrated airspeed and true airspeed.


Regardless, the uncompensated, zero reservoir vario will still allow me to center thermals. Although the indicated climb can differ from true, the VSI will give a more accurate overall value. For a conclusive measure of success, net altitude change determines the merits of each thermaling attempt.


--Ray

this quiet "paw" been customized as a generator carrier, light plane tug and more. a hoist may be added on. (got to read up on electric transmissions now..)

http://www.electricpaw.com/customdesigns.html

2cents, r

Great news! I found a way to get electrical power outlet at the airstrip I use. There is a hangar on the other side of the strip that has power. They are willing to provide me an external outlet for recharging.


So now, after every flight I will temporarily tie down next to the power hangar, recharge overnight, then return to taxi over to my hangar. Much easier and safer then trying to extricate the massive battery in and out of the plane.


--ray

why not an eOdyssey, Ray? why fly alone, when one can take family&friends&kids along, just one at a time. Congratulations!
rahul