Electrified Bird-Dog ( Kit #902 )

[SpiceMan]

Greetings to all you fellow Guillow's Airplane Kit lovers.

Recently finished my little Bird-Dog 3-Channel RC electric, and thought some of you might be interested in seeing it.

Did the maiden flight a couple of days ago. Had a couple of rough take-offs until I tweeked the rudder & elevator travels. After that ... turns out that she flies quite well. First flight was 5 minutes, and the second was 6. I like it.

I've posted a YouTube video Slide Show of the build if you're interested.
See it at: https://www.youtube.com/watch?v=a3H8DuD ... tDGGzbDUtg

Here are a few Pics.

[davidchoate]

What was your AUW?

[SpiceMan]

What was your AUW?

Hi David,

I'm thinking that "AUW" must stand for All Up Weight ... same as Flying Weight to me.

If that's what you're asking, the Bird Dog weighs in @ 46 Grams flying weight, compared to the Champ, which weighs in at 44 Grams Flying weight.

As of today, I've got a total of 7 very successful flights on the Bird Dog ( one 5-minutes, and six 6-minutes ).

Any more questions, or anyone else with questions, feel free to ask.

[Konrad]

Is the dihedral stock, per the plans?

[SpiceMan]

Is the dihedral stock, per the plans?

Greetings Konrad,

Yes, the dihedral is per plan ( no strut length reduction ).

In flight, my Bird Dog wants to "climb" quite a bit. Not sure if that's because I might not have put enough down-thrust in the motor angle, or if it's due to the extreme dihedral. I have a feeling that the down-thrust is OK, so if I were to build another one with the same set-up, I'd probably reduce the dihedral by maybe 25 to 50%. But even with the stock dihedral, she's a good flyer, even in moderate wind ... much like the Hobby Zone Champ.

Much more information than you asked for, but hope it helps.

[David Lewis]

To reduce climb under power you might trim in some down elevator or reduce (the absolute value of) stabilizer incidence. Glide tests will tell you what is needed. Generally you want enough up trim during the glide to maximize lift coefficient (equilibrium angle of attack) without stalling. Then you can fine tune the CG location through a series of dive tests. I'm pretty sure dihedral doesn't have any effect on longitudinal trim -- it only affects roll stability.

[SpiceMan]

To reduce climb under power you might trim in some down elevator or move the CG forward. Glide tests will tell you what is needed. Generally you want enough up trim during the glide to maximize lift coefficient (equilibrium angle of attack) without stalling. Dihedral doesn't have any effect on longitudinal trim -- it only affects roll stability.

Thanks for the info David.
I'll probably try the down elevator trim as you suggest. That will probably yield the slight improvement for more level flight. I hesitate to do any glide testing, because that's best done in tall grassy areas, which are few and far between here in sunny Phx AZ. Thanks again for your input.

[David Lewis]

No worries. As soon as the power cuts off, you can see what the plane does during the glide. Normally power-on and power-off phases are trimmed separately anyway.

[Bill Gaylord]

I just live with trimming these models a bit as David stated. The wing incidence is set by the fuse formers so it would be a bit of work to change, although the stab could be reset. My Robin loves to climb also. As a general rule after converting a number of these models, I've found setting the flat bottom of the wing at zero degrees (parallel) to the stab works well for r/c.

[davidchoate]

Although I cant brag about any recent flying successes. I have found that starting at zero degrees, I call it 'nominal', settings on the wing and tail, and then glide it. Maybe its My poor piloting, but My planes never seem to fly as straight as I glide trim them. And 2deg. down and 2deg. right thrust is My start point on the motor. This I just copied from Foam planes that work Well. Maybe David Lewis can help Me here. I notice that My foam trainers all seem to have a much thinner wing, and even a bit of undercamber. I do not kow why, or what effect it may have to use this in My building. I love to listen to people, and learn from them Thanx And I love your Bird Dog. Mine did well on rubber power, and I also considered it a candidate for an electric conv in future. Your build helps, and gives Me confidence I can make it work. Thanx.

[SpiceMan]

Thank you, guys, for your suggestions, comments, and compliments.

I'm assuming that you all took a peek at my YouTube Slide Show video that shows my process.

For anyone thinking of building the Bird Dog similar to what I did, here are a couple things that I'll mention that will probably help you out.
1). Bend the landing gear wire so it is makes the plane sit a little higher. About 1/4 inch should do it. This will allow for prop clearance to the ground when taking off. Mount the landing gear wire on the BACK SIDE of Former "C", and reinforce it vertically along the fuselage with some spare stringer sections, using Medium CA along the length. This needs to be done BEFORE the control board is installed.
2). Make yourself a "dummy" control board ( length & width ) out scrap balsa or light plywood. You can use the "dummy" to determine where to glue the control board supports to the sides of the fuselage, so your control rods will line-up properly. This worked well for me, and eliminated the risk of damaging the control board. For the control rods, I just started from the back of the fuselage and "poked" them through the formers, trying to aim them where they'd need to be to connect to the control board. After the former holes were in place, I connected the control rods to the control board and fed the rods from front to back of the bird. A little "flexing" was required here, but it worked, and the control board dropped right down onto its supports. Secure the control board ( and motor ) in place with some flexible adhesive of your choice. I think I used Canopy Glue, or Rubber Cement ... can't remember for sure.

[PsyberPhlier]

That is a nice Bird Dog, SpiceMan.

I plan to build one for the 2015 challenge. I can only hope its as nice as yours when done.

Ted

[davidchoate]

Nice Job ! I wish you had more photos of your build though. The climbing is just the way it is. The Champ climbs as you give it more throttle just cause its so light. I dont even need any elevator except to land or loop with it. I am definitely going to do a RC Bird Dog now.

[SpiceMan]

Ted and David ... thank you for your compliments and comments.
David ... your Bird Dog looks SWEET

My apologies for not responding sooner, but I've been working on my next project, which will be a Guillow's "Electrified Cessna 150". Taking plenty of pics along the way for another YouTube "Slide Show" when she's done.

As for the Bird Dog, shes now got a total of a dozen successful outdoor flights on her ( in light wind ), and still going strong. I'm using a crude flight tracking system by placing dots on the underbelly ( see photo ). Lots of fun to fly.

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