Flight Troubles?

Greg Doe
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Re: Flight Troubles?

Postby Greg Doe » January 7th, 2010, 2:46 pm

Shorti96,
The Freedom Flight props are the Ikara props. Scissors work great. Follow the kit instructions,
and just cut the tips off square to comply with the 20cm. rule. You can play around with different
tip designs, but most of us think you don't want to reduce the blade area, so squared off is a
good place to start. We put a small (about 1/8 inch) radius at each corner after we cut the tips
square. There is another wide blade Ikara prop that can improve performance, but it is not the
standard prop supplied in the kit. That prop requires some more serious rework. It probably
needs to be repitched, and the blade area modified. If you are interested in experimenting
you might consider ordering a few of these props. Good luck.
Greg Doe
Smyrna, TN

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planemaker
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Re: Flight Troubles?

Postby planemaker » January 8th, 2010, 5:03 pm

Greg Doe wrote:I have a lot of confidence in all of the Freedom Flight products. This years WS airplane is based on
last years nationals winning airplane, with 2010 rules changes incorporated. I have every reason to
believe that this kit will produce 3 minute flights in 30 foot gyms, and close to 4 minutes in 70 foot
venues (such as the Illinois State field house). I coach, but I also fly the same designs that my
students fly, in order to learn the airplanes flight characteristics. All of the kits that are available
are good. Which one is best is hard to determine. Obviously, a good design that is poorly built,
will not fly as well as poor design that is properly built. Read and follow the instructions. Build the airplane as carefully as you can. Trim the airplane for flight, as close to the instructions as you can.
If you are having flight problems ask for help. Try to find someone locally who has indoor free
flight experience, or post your questions here. Good Luck, and let us know how successful you were.
Greg Doe
Smyrna,TN

Thanks A lot Greg it is good to know that i have invested in a solid kit.
2010 events- Wright Stuff;Rad Scholar; and Bio Process

NORCAL 4 TW

Hamtown009
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Re: Flight Troubles?

Postby Hamtown009 » January 11th, 2010, 10:01 am

We have the new freedom flight models hit Greg. We already rebuilt our plane, and we have improved it by a lot. The motor stick is more stiff now, and the connection between the motor stick and the tail boom is a much stronger connection together. We are going to fly tomorrow. I'll keep you posted. Thanks
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Wright Stuff
Bio-Process Lab
Shock Value
Pentathalon
Write it Do it
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eta150
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Re: Flight Troubles?

Postby eta150 » January 14th, 2010, 8:53 am

I don't actually have a flight trouble, but i figured that this would be the place to ask why my plane under this years rules is going for 40 seconds longer (on average) than my best flight last year?
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jander14indoor
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Re: Flight Troubles?

Postby jander14indoor » January 14th, 2010, 10:22 am

eta150 wrote:I don't actually have a flight trouble, but i figured that this would be the place to ask why my plane under this years rules is going for 40 seconds longer (on average) than my best flight last year?


Where do you get 40 seconds longer than last year with the new specs? For same height, I don't expect that much change for same level of trim.

In other words, if you could fly three minutes (nationals winning time, close to limit of capability) in a 'normal' 30 ft high gym I don't see 3:40 with this years specs. If you could fly two minutes last year in the same site, you might get to 3 minutes this year with improved trim, not because of the rules changes.

Now, going from that 30 ft nationals site last year to this years nationals site with its 100 ft ceiling, more time is possible under both the old and the new rules. Guesstimates are around a minute, but little hard data yet.

Side comment, I'm not sure how close last years winning time was to the full capability under the rules, I suspect more time is possible, but its a good chinning point.

Jeff Anderson
Livonia, MI

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eta150
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Re: Flight Troubles?

Postby eta150 » January 15th, 2010, 4:56 am

It was 2:50 in a 22' gym (on my third flight) as compared to last year having a best flight of 2:10 in a 30' gym.
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Re: Flight Troubles?

Postby jander14indoor » January 15th, 2010, 6:19 am

OK, I doubt rule differences caused that. What are the detailed differences in your plane, this year to last. Weight, wing dimensions, tail dimensions, design differences, prop-rubber combinations.

I strongly suspect the difference is not due to rules, but either last years plane was not optimum, or it wasn't well trimmed. Both may have been fixed by what you learned last year. Details as requested above will help sort out what you improved so you can repeat it.

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Re: Flight Troubles?

Postby jcollier » January 21st, 2010, 5:11 pm

eta150 wrote:It was 2:50 in a 22' gym (on my third flight) as compared to last year having a best flight of 2:10 in a 30' gym.


Good time! :D

As far as the difference between last year and this, the only real rules difference is the larger horizontal stabilizer. It's just a guess but I would think that might be worth 15-20 sec. at most. If your wing last year was not as big as it could be, that might explain some of the difference. The rest is likely better trim, or a better prop/rubber combo.

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Re: Flight Troubles?

Postby Hamtown009 » January 22nd, 2010, 8:27 am

When we fly our plane, it tends to climb, but not fly consistently at a height of 6-8 feet. It flies for about 10 sec when it is 1 foot above the ground. Why is it consistent at a low elevation and not a higher one? (dimensions are ----- tail boom and motor stick: combined is 60 cm, wing: 37.5 cm, Horizontal Stabilizer: 18.5 cm prop is 20 cm in diameter)
2010 Events-
Wright Stuff
Bio-Process Lab
Shock Value
Pentathalon
Write it Do it
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calgoddard
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Re: Flight Troubles?

Postby calgoddard » January 22nd, 2010, 9:50 am

I am not sure I understand your question, but maybe this answer will help. When a Wright Stuff plane is flying very near to the ground, if there is still sufficient torque in the rubber motor, the plane my experience ground effect. This is a phenomenon that provides extra lift, so the plane drammatically slows its rate of descent and may fly for a third or a half of a circle only a few inches above the ground.

During the cold war, the Soviets built a number of ground effect vehicles that used a stubby wing configuration very close to the surface of the water to lift massive loads. Enter "Caspian Sea Monster" into the Youtube search window if you want to see some fantastic videos of the largest of these Soviet vehicles in flight.

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Re: Flight Troubles?

Postby calgoddard » January 22nd, 2010, 10:01 am

See my last post.

The largest Soviet ground effect vehicle was called the Ekranoplan.

Here is a link to a Youtube video showing the same in flight, and giving a history of its development:

http://www.youtube.com/watch?v=rUTWWsh6iGA

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Re: Flight Troubles?

Postby jander14indoor » January 22nd, 2010, 10:04 am

calgoddard got it exactly right about why it flys nice close to the ground. Ground effect improves the lift of any wing.

As to not climbing, the usual suspects are too heavy, motor not wound HARD enough, too high prop pitch (or too skinny motor), not enough elevation from the rudder.

Oh, and for nice cruise in mid flight, you want the plane cg and elevator trimmed VERY close to a stall, just short of it. In fact as you descend on low power you may see some stalling. If so, you are close, trim for just a hair less elevator at that point. That should give you a good climb at the beginning with a FULLY wound motor. And yes I know about backing off to avoid ramming into the ceiling. You have to get TO the ceiling first.

IF everything else is right, (minimum weight, max wing, trim seems right, motors wound to near breaking, right prop motor combo) and your plane just won't climb, try adding a tweak of wash-in to the inside (usually left) wing. Washin means you raise the leading edge SLIGHTLY wrt to the trailing edge at the tip vs at the root of the wing. Said another way, the angle of attack for the inside wing tip is higher than the angle of attack for the root or outside wing tip. In still other words, if the wing is level to the motor stick at the root rib (center of wing), the leading edge should be say 1/16 to 1/8 inch higher than the trailing edge at the tip. Go slow here. You are trying to make the plane fly level in the circle, maybe SLIGHTLY inside wing low. Note, the outer wing should remain flat, same angle of attack at root and tip. I'm not really sure why this works, but it does, repeatably.

Jeff Anderson
Livonia, MI

sr243
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Re: Flight Troubles?

Postby sr243 » March 4th, 2010, 5:16 am

I am not doing this for competition but needs to help my team not fail at this event. So far i have built a plane that glides decently with the propeller but the plane doesn't fly. I am not sure exactly why but i think it might have to do with the rubber band. The rubber band was from a kit and worked kinda well except after 1000 rotations, it snaps. When i use half the length, i can only get 500 rotations and it dies in 15 seconds, but my plane fly upwards for a while. When I use the full length (about 70cm) it doesn't fly and fall down after 10 seconds. Otherwise i suspect my wings aren't getting enough lift since I attached them on to the motorstick directly. As for weight, the plane is about 9g. Regionals are next week so I am trying to get a plane that goes for a minute by then.

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Re: Flight Troubles?

Postby jcollier » March 4th, 2010, 7:27 am

One week? OK, from what you are describing, it sounds like your plane needs a lot of power to fly at all. Your center of gravity may be too far forward (probably is), or the wing's angle of attack is not giving enough lift. With only one week to go, the 9 gram thing (compared to the minimum 7) is something that will have to wait. You can try putting a little bit of clay at the very far end of the tail boom, right at the stabilizer to help your CG. That is something you can try without changing your plane. I saw some 9-10 gram planes fly for close to a minute at states last year, so it can be done. A better way would be to cut the wing off and use paper tubes and wing posts to allow you to adjust the wing. Little changes make a big difference. Last night, my son got an added 20 sec. with a 1mm wing post change. That may be too risky for you with so little time to regionals, so you have to decide what you are willing to risk.

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Re: Flight Troubles?

Postby sr243 » March 6th, 2010, 10:57 am

Thanks for the advice, and I have redesigned the plane and now it should be around 7 g but my question is where should the center of balance be for the plane? Right now the center of balance for my new plane is about 20 cm from the front and 28 cm from the back. Should I add weight to the back? Also is it okay to test outside because I don't have a gym I can access for testing? BTW I live in Wisconsin where thre is snow on the ground but not much and no wind.


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