O-1/L-19 Birddog Flight Dynamics Modification Update

Everything concerning Cessna O-1/L-19 Bird Dog is discussed here.
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Blackace16
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O-1/L-19 Birddog Flight Dynamics Modification Update

Post by Blackace16 » 07 Jun 2010, 07:25

During the past year I have been involved with other testers in assisting the developers in creating a realistic simulation of the venerable O-1 Birddog. The credentials I have brought to the project have been in the form of actual flying experience in the O-1. I have logged over 900 hours of pilot time flying O-1A, D,E,F and G versions of the bird. Most of that flight time was in combat. Between April of 2009 and December 2009, I provided input to the developers regarding technical, visual, and flight dynamics issues. After testing several beta versions, the product was released by the developers for sale in December. At the time, I and other testers did not feel comfortable with the flight dynamics of the bird. Visually, the bird was (and is) stunning. The overall quality of detail is second to none. But both the ground handling and in flight characteristics were less than acceptable.

The developers realized that the flight dynamics of the product were not acceptable. Those of us trying to assist the development team were also frustrated because of the difficulty in articulating what needed to be done to improve fight characteristics. Consequently, the development team decided several weeks ago to seek assistance from an outside source with a proven record in creating realistic flight dynamics for flight simulation aircraft. They contacted Alexander Metsger who has a proven track record in flight dynamics development (http://www.metzgergva.de/site/). Alexander was provided with a U.S. Army O-1 Operator's Technical Manual which described the flight and mechanical characteristics of the bird in precise detail. Armed with that information, Alexander went about the process of developing a realistic flight simulation. A new air file was created and tested by myself and several other highly capable testers with a good knowledge of flight physics. With our input, Alexander revised and fine tuned the file several times.

The last file was finished several days ago and is a vast improvement over the original. In fact, in my estimation, Alexander has done a superb job in duplicating both ground handling and in-flight characteristics. Just like the real bird, the aircraft is a little tricky handling on the ground. For those of you who might not be aware, in real life the bird is noted for being a very unforgiving aircraft on the ground and is noted for its tendency to ground loop if one loses directional control!! In the air, however, the real bird is a pure joy to fly -- and so is the revised simulation air file. The bird now closely resembles reality in several key areas: air speed and landing characteristics in full range of flap and throttle settings, in-flight power -on and power off stall characteristics, glide characteristics, etc. Takeoff characteristics are now much closer to reality with about the right amount of right rudder needed initially to overcome the p-factor. In all, a great simulation.

I have contacted the developers to find out when they expect to release their revised bird to all of you out there who are waiting patiently to get the new revision. According to them, they are 98% ready to go. During the testing, several other physical and mechanical operational glitches with the flight instruments were noted by testers. The team wants to correct those issues also and then have the testing team try out the revisions one last time before making a formal release of their final product. I can understand this as it has been clear all along that they are very detailed minded and want the bird to be as perfect as possible. The problem they have is that this project is not their main occupation. At present, they are finding it difficult to find time to complete the project due to other priorities. Unfortunately, I could not get any time line as to when they expect to do a final. So folks, for all practical purposes we are in a "holding pattern" to use an applicable aviation term. In the meantime, I have decided to make available to you the same manual Alexander used to fine tune program flight dynamics for the O-1. You can download it at: http://www.4shared.com/document/n-yXuZp ... anual.html. This was my bible during my birddog flying years!! Hope you enjoy and happy flying!!
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Ron Attwood
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by Ron Attwood » 07 Jun 2010, 13:39

I'll recall the guys who were on their way to Moscow then. Terrific post.
Computer: Black box with a bunch of electrical looking stuff inside. Lots of fans and blue lights and it sits there humming away gently and lets me play games on it.

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thunderstreak
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by thunderstreak » 08 Jun 2010, 00:39

Can't friggin' wait! Thanks for your efforts Blackace16!!
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bmd
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by bmd » 08 Jun 2010, 18:21

Hello Blackace16,

Thank you very much or the copy of the O-1 Pilot Operating Handbook. It is a gold mine of technical informations about the Bird Dog.

Thank also for the information about the Flight Dynamic developmeent of the Bird Dog. I am sure that, with a realistic time scale, the Team will bring us an already wonderful model with a realistic dynamic behavior. It take time to test everything but the result will be great.

Have a good day

Benoit

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Ron Attwood
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by Ron Attwood » 08 Jun 2010, 20:38

Computer: Black box with a bunch of electrical looking stuff inside. Lots of fans and blue lights and it sits there humming away gently and lets me play games on it.

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mos
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by mos » 08 Jun 2010, 21:53

Sounds promising. Thank you "Blackace16" for your information.

(by the way, great photo)

sg38
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by sg38 » 09 Jun 2010, 16:21

Does she spin now? When they kicked me out of the beta team for the 'new' FDEs she wasn't capable of that and had an awful 90deg pitchup during the stall.

Blackace16
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Location: Ripley, OH - The Villages, FL USA

Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by Blackace16 » 10 Jun 2010, 18:26

The bird spins now -- more consistent with real world capabilities. However, in accordance with the U.S. Army's operator manual, spins should be entered clean (no flaps) since the use of flaps puts unacceptable stress on the fuselage. Although the engine is relatively large (213hp) the aircraft was not designed to do acrobatics. The purpose of the large engine and flap settings is to give it a shortfield takeoff/landing capability and a relatively high climb rate.

Jigsaw
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by Jigsaw » 10 Jun 2010, 23:27

Thanks for the heads up and also thanks to everyone involved in redoing the flight model. The flight model issues where the only things that I didn't like about the Bird Dog. It will be an excellent plane with the new flight dynamics, no doubt.

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Ron Attwood
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by Ron Attwood » 22 Jun 2010, 23:24

A few more days. :grin:
Computer: Black box with a bunch of electrical looking stuff inside. Lots of fans and blue lights and it sits there humming away gently and lets me play games on it.

hews500d
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Re: O-1/L-19 Birddog Flight Dynamics Modification Update

Post by hews500d » 22 Jun 2010, 23:41

Wow! I'm glad I took the time to check the Sibwings forums today! I had almost given up on enjoying the Birddog after trying it again this past weekend. It's a pleasant surprise to hear the update is almost ready (hopefully :) ) plus to find the "real" O-1 manual available for download. Thanks Blackace16 !!! I'm looking forward to putting it to good use with the new flight dynamics.

Darrell

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