Productive Flight

[flyguy]

Last Friday I needed to fly up to a little airport at Lincoln, Calif, about 130 miles north from here. Was time to get the T's rear struts tested.
Sometimes we can get a lot of wind in the summertime here, but I, just by luck, got a REALLY quiet day.
Found out what my 12D-85 actually cruises at--at least for one power setting.

It apparently was dead calm all the way up and back as I got the same numbers both ways. I was trying to run about 2150 RPM, as my experience is that higher cruise than that just burns extra gas without adding proportionate speed. Generally my philosophy is to use the extra HP for T/O and climb.

At 2150 and 3,500 feet I was showing 85 MPH GPS most of the time. The time vs distance in both directions gave the same number.

Had to back down on the power to a pointer width over 2100 several times as it was doing an altitude creep up at 2150 and I was having trouble getting a precise trim with the tab, so I know it is a good solid number.

The fuel consumption worked out to 4.47 gal. per hour, which agrees with the factory charts. If my calculations are correct that is just short of 18 miles per gallon. That is without any mixture adjustment.

I flew almost the entire way up and back using just my feet and the throttle. It was pretty funny that I found the few times I got a slight descent that I could get a noticeable trim up by putting my right arm up across the seat back.

The rear struts both tested good and it was an enjoyable and informative flight.

This week the town (Lincoln) darn near blew up when a bunch of railroad tank cars caught fire. I missed the action by a few days.

Darryl

P.S. I cannot imagine flying her for 4 hours straight as I did when I brought it home from the desert in Souther Cal. Someone would have to pry me out with a crowbar. Chuckle.

[TimHicks]

Re: Productive Flight

Nice!

[Hank Jarrett]

Re: Productive Flight

Darryl, Did you consider that you could have been in cloud street lift or sink? Were there any long strings of Cumulus clouds nearby? I once really messed with a C-150 driver flying from Hampton Roads down to Kitty Hawk. We had two BIG guys in a 65hp Taylorcraft and he was alone in a 100hp C-150. We flew all the way down along side a cloud street where we were in the lift and he was on the other side of the rotor in sink. He would dive and catch up to us, a couple hundred feet lower. He would then try to climb up with us and fall way behind. He was at a high power setting all the way (he said wide open, but I doubt it). We were throttled way back and just loafing along. He wanted to look under the cowl when we landed. Didn't believe we only had 65hp. REALLY built up the Taylorcraft myth that day of the "built in tailwind! I sure wasn't going to tell him how I did it.
Hank

[flyguy]

Re: Productive Flight

Hank, are you implying that 85 MPH GPS is FAST? Chuckle. I was hoping for something more towards 90 but I guess I actually knew better. Though I must add that it might be more towards 87 or so as I kept having to power trim down close to 2100 and I have got that number before under less perfect conditions though.

I have 8.00 tires and no fairings on the outer strut attatch points. This one is almost 900 lbs empty and that doesn't help. This was just the first time that I got an absolutely for sure minimum solid number.
As for up or down drafts, this is central valley California in the summer. One hundred to 300 miles any direction to anything like a hill and clear skies totally devoid of clouds from about April to September. Pretty good thermal bumps are common if there is a cool evening the night before, but this day was slightly hazy and DEAD calm.

My airspeed indicator was of course giving me a nice feel-good number that has no relationship to reality. As an owner of 3 different BC12's over the years I have checked thoroughly and concluded that the static location in the wing is typically good for about a 10% high reading on higher indicated airspeeds. Pretty much dead on down by stall. Checked with multiple certified indicators, same results always. Likely low pressure inside wing as speed goes up. Makes everyone feel good though. LOL. Typical offset would be 116 indicated at 108 true.

I've done thermals in sailplanes and tried it with Tcrafts, but this one seems to be a bit heavy for it. Done close in ridge lift too, but not in this airplane.
Always good to get solid information and have fun at the same time.
DC

[Hank Jarrett]

Re: Productive Flight

No, I was thinking you were more the C-150 in my story and just hoped you were in sink that day. I wasn't aware you had soared and would recognize a rotor.
I plan to do some serious test flight work with mine when she is finished. I have been playing with some ideas on how to find the zero net thrust throttle setting real time so I can measure the L/D, minimum sink, total drag coefficient and a bunch of other fun stuff. We need to find out where all that drag is coming from. You should be faster (and LIGHTER) than that.
I have thermaled my 41 and it was a BLAST! Flew just like a 2-22 with a wheel instead of a stick. Wish it had spoilers.
Hank

[flyguy]

Re: Productive Flight

I had a 45 that was apparently built with the last of the prewar wings. Also no radio or battery, headliner, baggage, extra tanks. Engine was 65 with an -85 carb, (intake?) but still had a long prop, 7446. Would wind right on past 65 redline. Records showed 730 lbs as I remember. Man would that thing climb. I took it to 12,500 one winter and it still was going up strong.

The -85 I have now was one the guy (an AI) tried to turn into a airliner. Extra gauges, standard-sized panel radio, heavy battery, strobe, two complete coats of finish (ie 4 total, like thick.) 24 gal tanks, big tail wheel, you get the idea. Done on 337 with no weight upgrade. With the 85 it still goes up initial about 850 ft/min., but it is really heavy. With full tanks I am allowed 8 lbs of baggage. Front tank only, one skinny kid only as passenger.

By the way, I have some drawings I made of a exhaust heated White-boiler-type steam JATO system that you would be amused by, I'll bet. I have always been interested in devices and ways to utilize the huge waste heat that comes out the exhaust of IC engines. Turbo-compounding and all that stuff. A classic IC engine engineering book I have shows some shocking numbers for waste heat. What the heck, it keeps my brain active better than playing checkers. LOL.
DC

[Robert Lees]

Re: Productive Flight

Turbo-compounding and all that stuff. DC

For about 25 years I've been looking at an IC-powered ducted fan, with reheat for takeoff. I know turbo-compounding is different (R4360's, or Constellations or both?), as is water injection, but for lightweight aircraft, simple boost would help at critical flight times. Not for Taylorcraft, however...you need air bypass.

[flyguy]

Re: Productive Flight

Rob, how about 2 of these. One on each strut. Check the fuel consumption rate. Wow.

http://www.jetcatusa.com/p80.html

DC

[Hank Jarrett]

Re: Productive Flight

Check the fuel consumption? Check the PRICE! $2,395 for the P80-SE and they have one (the P200-SX) that runs $5,496! Of course for a working gas turbine that is pretty reasonable. The P200-SX has 52# of thrust. If we hung 8 of them from the wings we could pretend we were flying B-52s! How fast could a Taylorcraft climb with over 400# of thrust?
Hank

[magman]

Re: Productive Flight

I don't think it would go UP faster than the bank account goes DOWN.

[flyguy]

Re: Productive Flight

Soooo, question is (that I want to know) have always been curious about--how much static thrust does a 65 or 85 HP engine with say a standard (whatever that means) prop generate at full throttle? Would give one some idea of the performance possibilities.

Anyone ever see any numbers on a Longeze with the jet engine? Has anyone ever actually flown one? Not the rocket version, but the turbine.

As for the 52 lb one, I suspect just one slung under the fuselage of a Tcraft would be pretty exciting.

DC

[Hank Jarrett]

Re: Productive Flight

Kind of like that WACO they used to bring to AirVenture for aerobatics demos. Could climb like a scalded dog!
Hank

[TimHicks]

Re: Productive Flight

Soooo, question is (that I want to know) have always been curious about--how much static thrust does a 65 or 85 HP engine with say a standard (whatever that means) prop generate at full throttle? Would give one some idea of the performance possibilities.

Anyone ever see any numbers on a Longeze with the jet engine? Has anyone ever actually flown one? Not the rocket version, but the turbine.

As for the 52 lb one, I suspect just one slung under the fuselage of a Tcraft would be pretty exciting.

DC

I'll take a crude swipe at this. If Hp = Torque * RPM / 5252,
then at 65 Hp and 2300 RPM, Torque to turn the prop would be about 150 ft#.

Of course, not all of this is in the direction of flight, but if we assume 85% efficiency and that the average resistance happens at about 2 feet from the hub, the static thrust would be about 60#. Adjust the numbers as you see fit. Most of these are crude assumptions, not realy data.
So yes, in the ballpark of these turbines.

[Hank Jarrett]

Re: Productive Flight

How about one of us just go our and put a fish scale on the tail wheel to a fence post and start her up? Tom did it the engineers way, the way anyone in my office would probably start out. I am guessing you are just a wee bit off. I am guessing the thrust should be between 300# and 350#. Prop theory isn't as intuitive as you would think. I wish my plane was ready to fly, this is the kind of thing that is really fun to do.
By the way, if someone decides to try this get a second person to read the scale and have a couple of extra ropes to the lift handles. If that scale breaks you could be on a weak, but danged scary, cat shot!
Hank

As a second note, the thrust IS NOT the same in flight as static! One of the reasons I am looking for a way to set the zero thrust rpm in flight so I can adjust the power to simulate no prop.

[Larry Lyons]

Re: Productive Flight

The EAA has done this with a sensor that shows the position of the prop shaft forward and back while in glide. I just remember the name! CAFE competition I believe. Don't reinvent the wheel; or am I so far behind that down looks like up? L