Chuck,

THAT IS A BEAUTIFUL DIRTY BIRDI!!

Great job. Good luck on the maiden.

Gene

Thanks for the kind words David and Gene!
The flying season starts late up here, ( we still had snow this week, but I should get the maiden in within a month.

Hi Chuck. Glad to hear that the notes were helpful. You've got a nice looking DB there. It should really cook with the piped FSR and retracts!

Dave

Hi All,

I did maiden the yellow Dirty Birdy today. It flew great, took me right back to the 80's when I first flew pattern competitively. It only needed one click of down trim. My CG is 1/4 inch ahead of what the plan showed for safety on the first flight, but it seems just right, no pull out in a hands off vertical power off dive.
I set the wing incidence at just shy of 1 degree. I will go through the trim process, but right now it loops straight and doesn't pull in knife edge, so I think it will be an easy trim job.

The OS 61 FSR I got on the famous bay for $60 started with little fuss and tached at 14K plus with an APC 11X7. A bit too much I think, I hate using too many glow plugs up, so I changed to an 11X8 which it turns at 13,100 on the ground. I haven't flown it with that one yet. It was fast with the 11X7 and nearly unlimited vertical. An OS 55 would be plenty and would have saved 4 ounces of tail weight in my case.

However, it flies with a light feel at 7 pounds 3 ounces and slows down nicely to land. Even the retracts worked flawlessly, except I think I will need to find a check valve to put in near the fill because it leaks too much out as I remove the air pump. I only get two cycles. Does anyone make check valves that fit our thin air lines?

Once again thanks dbaque for the instructions that helped me get things right the first time! They really made a difference.

Chuck

Chuck,

Good to hear the maiden went well, sounds like you've got a great airplane.

You're very welcome for the notes. Glad they were useful.

Dave

I have a "nib"DB plan on building it this winter for upcoming "SPA"contests. I have flown in one placed 2nd with a kaos(it was my first ever contest)
I would gladly except any info you have on the build, an flight trimming of the db. Tks in advance
Falcon

I have a "nib"DB plan on building it this winter for upcoming "SPA"contests next year. I have flown in one placed 2nd with a kaos(it was my first ever contest)
I would gladly except any info you have on the build, an flight trimming of the db. Tks in advance
Falcon

Once area that can give you trouble is engine mounting. The plane is designed for a small block .60. Compare your engine to the plans to see if you'll have to make any firewall location adjustments.
Another area of "greyness" is mounting the stab. Be sure to mark centerlines on the fuse sides at the horizontal stab location before building the fuse. In fact it may benefit you to go ahead and cut out the stab opening before building so you can compare the cut-out to the plans.

Other than those two items, PLEASE round the top of the fuse as it shows on the plans. Some people give up early and just round the edges. Looks soooo much better when it's done right.

Jeff is spot on in everything he mentions. The engine mounting and cowl carving would be much easier with a small case like an OS 55. That would also save tail weight ( 4 ounces or so in my case). I have an OS 55 and removed my 61 FSR just to check and it would balance nicely without the tail weight with the lighter motor. Read all of Dave's revisions, they saved me a ton of time and helped make the airframe more precise. Pay particular attention to his incidence notes and the notation that the plans show one side of the stabilizer longer than the other. He has done us a great service by taking the time to make these notes!

Chuck

Xacto makes a decent plane for shaping blocks. Cheap and helps get the material removed in a neat and quick fashion!
Chris...