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Old May 29, 2002, 03:12 PM
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TedLarson's Avatar
Los Altos, CA
Joined Sep 2001
607 Posts
Schreiner F-18 Project - Part #2

I am getting close to completion on the Schreiner F-18 project. The only things remaining to do, are securing the canopy, balancing the plane and reinforcing my battery box to I can be 100% sure those 5 pounds of batteries won't come loose in-flight.

If all goes well, I will be attempting the first flight of this bird this coming Saturday, June 1st. I normally fly at Rancho San Antonio Park, however, the Tomcat field in San Jose is having an electric fly-in on Saturday. They have a nice, big, paved runway, so it will be a perfect opportunity for the test flight. I know alot of you have ancitipated the flight of it for quite some time. I have been talking about it non-stop for the last 6 months as I built it.

Anyway, if you want to see it fly, show up at Tomcat's on Saturday. More information about the fly-in can be found on their website at: http://www.sccmas.org

No matter what, even it is not ready in time for the flight on Saturday, I will bring the plane with me, so all the RSA flyers can check it out in-person.

Thanks again to Gordon "Plane Crazy", and Joe "UncleJoe" for all their help getting this moster bug together. I would have torn my hair out without your guys help and support.

Here are latest pics, I just shot today.

- Ted
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Old May 29, 2002, 03:25 PM
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Los Altos, CA
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Here are some shots of the inside, when I was installing the Schubeler fans. Joe, you will be happy to know, that I went for a similar mounting scheme you went for, although I am not quite the lite-ply master you are...;-) You can see my 1/16th in fan saddles in one of the photos.

The plane is powered by Twin 90mm Schubeler Fans, with twin Hacker B50-15L's, 44xCP-1700's Zapped. I followed Gordon's advice and went for the dual Schultze 55-bo speed controllers. This setup should give me over 200 watts per pound of power.

It has Spring-Air 305 retracts, with working gear doors. You can see the retract main mounts located just below the fans. The wheels pull up in the small gap between the wall of the plane and the ductwork, and take advantage that toward the bottom of the duct, the curvature widens the space slightly. I used 2 1/4" Sullivan Skylite wheels. The 1/4" made the difference. Everything barely fits. It took me a month to get the mounts designed right so that it would all fit together.

I have not taken a final weight on it yet, but so far, I am guessing it will weigh in between 11 and 12 pounds.

- Ted
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Old May 29, 2002, 03:36 PM
Col.Hooligan Air Force
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Joined Jul 2001
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Ted
you did a great job,........ to acheive the CG with ease try X the sets of batteries. using the Lex areas to support the ends of the packs the other packs between the intakes (worked for me) note for CG :Gear UP
IF it tracks ok , it should become airborne in 200 some feet FLaps 10 to 15 %
keep power up in turns. Good Flying

BUGS RULE !!!!
Joe
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Old May 29, 2002, 07:48 PM
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Awesome Ted!

Wow, you have been working. I can't wait to see it. I will try and make it to the maiden flight on saturday. I have not been doing any flying for a couple of months now, just too busy to build one after my spit lost a wing in mid air and did the old death spiral.

What time are you planning on going to the Tomcats site?

regards,

Jonathan.
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Old May 29, 2002, 11:41 PM
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Johnathan: The fly-in starts at 8:30am. I am going to try to get there as early as possible. The current weather forecast for this weekend is calling for cooling weather, so I imagine it will get a bit breezy in the afternoon. I would like to get the flight in before the winds come up.

Joe: Did you find you had to mix in any elevator on your flaps?
The flaps on this bug are gigantic. Also, did you balance the plane per the mark Axel made on the paper instructions? i.e. 110mm from the leading edge? Or did you find the balance point needed moving?


Thanks,

- Ted
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Old May 30, 2002, 01:29 AM
Col.Hooligan Air Force
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CG

Ted
Used the mark 110 mm from leading edge

Did not mix Flaps & Elevator should have as you know it was a short flight , Yes the flaps are HUGE, great brakes might need 200 or so feet for take off but for ~ 12 pound aircraft you can stop it in 100
No surprises, , let it take off ,get the airspeed , then enjoy .
Joe
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Old May 30, 2002, 04:04 AM
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France, RA, Yvoire
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Ted,

Terrific work you did with this one, looks sooooo great
All the best for your first flight, keep us informed...

Olivier
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Old May 30, 2002, 11:01 AM
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Boy, I wish I could see this one... Please keep us posted, Ted.

Is there anyone with a small plane in the Eugene area who want to fly to San Jose on Saturday?
:o)

Dieter
http://shredair.com
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Old May 30, 2002, 11:35 AM
Col.Hooligan Air Force
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Phoenix,Arizona
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Ted
How are you securing the main hatch and canopy ? I used masking tape (real high tech) . Have latch pins for main hatch just haven 't installed .FWIW.... For the first flight I would keep it the flight to 3 mins that way if you need to go around again you have the power


Semper Fi
Joe
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Old May 30, 2002, 02:30 PM
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Beautiful model Ted,great scheme too!
Best of luck with test flights,I'll be watching with great interest.

Matt.
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Old May 30, 2002, 02:46 PM
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Looks good! Good luck on the first flight ...



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Old May 30, 2002, 03:19 PM
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Los Altos, CA
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Great photos Herb! Good inspiration. Hopefully mine will fly as beautifully as the one in your photos.

Joe: I used 3 small screws to secure my canopy two near the front on each side, and one in the rear. I have this thing about scale-looking aircraft needing a pilot, so I temporarily mounted jet pilot bust I found at the LHS in the cockpit. He is a bit large, but he will do until I can find a better one. I attached a small, spring-loaded, hobby latch to my fuse cover, and I plan on using small wood tabs to hold it in place. I haven't finished this yet. I am going to try to get this done tonite.

I will shoot some snapshots later, and post them so you can see what I am talking about. By the way, I got your battery mount photos...they look great! I actually, already went for a really different approach. I will make sure to shoot a picture of it too.

All that remains are detail items to finish now. The hatch, final receiver mounting, a few tweaks to my gear door wires, final balancing, and a full-throttle engine test in the back yard.

A buddy of mine who owns a video camera is going with me on Saturday, so hopefully we can get some good video.

- Ted
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Old May 30, 2002, 03:50 PM
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Reno, Nevada
Joined Jan 2001
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Hey Ted..Don't forget to make sure the Schreiner F18 will fit in your car. . Boy that would be a bummer.

Don't forget the range checks with the fans running all out.

Most of the hatches on mine used 2 metal pins on the front with a screw or spring latch on the back. The metal pins slipped into holes in the fuse hatch openings.

Good Luck

Gordon
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Old May 31, 2002, 01:33 PM
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Los Altos, CA
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I did a full-throttle engine test last nite, on fully charged packs.
I was speechless. WOW! Incredible power!

Those Schubi fans sound like mini turbines when they are dialed-up. I taxied around the driveway a-bit. This bug really wants to fly. I don't think it will have any problem getting off the ground with the amount of thrust this thing produces.

I do have one concern though. I hooked my current-loop up, and at full-throttle, I am drawing exactly 55 amps per side. My calcs indicated it should be more like 49 or 50 amps. Could it be that the advanced timing on the Schultze speed controller is causing the extra draw? Perhaps I should switch to mode #2? Opinions?
I am sure my draw will drop some once I am in-motion, but this seems a bit high.

At 55 amps, those battery packs get mighty toasty. Although, the motor temp seemd ok. I should probably jam a thermocouple up one of the tailpipes and into the back of the motor tube after my first flight and see where the motor temp is. I am definitely pushing it.

I think I better pick up a small halon extinguisher to take along on the first flight, just in case I have a fire.

Gordon....how many amps do you estimate you were drawing when you blew one of your Schultze 55-bo's?

Thanks,

- Ted
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Old May 31, 2002, 01:53 PM
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Irvine, Calif USA
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Quote:
Originally posted by TedLarson
...I am drawing exactly 55 amps per side....- Ted
Consider the following three points:

1) Fans don't unwind a whole lot in flight unless your plane is ultrafast and your fan is super-pitched (I did a few Doppler measurements of various planes in flight vs static), so it's a reasonable guess you'll be drawing close to the same current in the air.

2) As you cycle your new NiCd packs, they'll get better and will deliver more punch. So your Amp draw on the next few flights could go up a bit.

3) Hackers run fine & efficiently on moderate advance timing (2-5 degrees), they don't need more.
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