Bücker Bü 180 Student Swappable - design, build, and review log

[nerdnic]

Now you've done it. Another one added to my build list. I'd love a set of plans for a Moth Minor!
I'm now building with depapered foamboard and tape from the Tape Brothers and just happen to have a whole unopened roll of yellow tape.

She would look great next to my yellow Tiger Moth.

Owen

Okay, I think I'm gonna do it once the Bucker is done.

 

[nerdnic]

That would be awesome, nerdnic! Astute observations. That eliptical elevator and its placement/size are very different. I'm interested to see how they perform.

I'm looking for some good plans to reference but I don't think it will be that big of a difference.

 

[nerdnic]

I decided to scrap my beta 1 fuse and build beta 2. Boy am I glad I did! Beta 2 came out GREAT. I feel really good about the design changes and now she looks like an actual Bucker Bu. I will post the new pictures and beta 2 plans in the next day or so. I plan to maiden her within the week and at that point will finish any last tweaks to the plans and release the finale version.

 

[JohnRambozo]

Awesome. It sounds like its time to order my servos.

 

[JohnRambozo]

Edit: Here is a link to a downloadable PDF of some dh.94 plans!

https://dl.dropboxusercontent.com/u/33290287/mmplana4.pdf

 

[nerdnic]

That does help, thanks!

What servos are you ordering?

 

[JohnRambozo]

I'm actually piecing the pages from the pdf into a single image for you. They're scanned with a lot of overlapping sections so it will be easier to look at when I'm done. Maybe another half hour.

I just bought the combo pack from Altitude Hobbies. They have Suppo SP-90 9gram servos. They seem to work well at about $3 each. Do you have some advice in that regard?

Edit: And done. Here's the link to the clean version I pieced back together for you. It should be a pretty good scale. If you have any trouble opening it, let me know and I'll try another format.

https://dl.dropboxusercontent.com/u/33290287/dH94minorMoth.tif

 

[nerdnic]

I used the 3 dollar 9g for a while but I would always strip them out in the car or what not. So I switched to using these 12g metal gear servos http://pages.ebay.com/link/?nav=item.view&alt=web&id=271228503456

They are the same size as 9g but are smooth as butter and I've not stripped one yet. They center very well and I have about 20 in use over the last few months.

Thanks for taking the time on that image, it will help a lot!

 

[JohnRambozo]

Those do look pretty sturdy and at the speeds you're flying, I'm sure you need them. I'll probably grab some. Just so I can be ready, can you tell me what length servo extensions will be needed?

As for the image, I figured you're doing all the hard work designing and testing. The least I could do is save you the effort of piecing those reference plans together. You have more important things to focus on.

 

[nerdnic]

Awesome thanks man!

I'm going to finalize the beta 2 plans and post them tonight along with the pictures of the beta 2 all finished.

 

[JohnRambozo]

Yes! I can't wait. I have foam board at the ready! I have next week off. I'll likely be spending some time building your Bucker.

 

[nerdnic]

First post updated - Beta 2 build photos and plans added!

I couldn't be happier with how the design and build has turned out so far. For my first literally from scratch build it's been a great experience and I hope the final product is worth all the effort. This might be the start of many nerdnic planes I plan to maiden her in the next day or so and will definitely have a video to post.

If you guys have any questions let me know!

 

[JohnRambozo]

beta2

Great job, nerdnic! I can't wait to build it. Beta 2 looks so good!

What are you using for control horns and push rods?

 

[nerdnic]

Flossing sticks
http://flitetest.com/articles/the-cheapest-quickest-control-horns-ever

Bendable wire run through coffee straws
http://www.lowes.com/pd_51214-1463-...1&currentURL=?Ntt=100+hanging+wire&facetInfo=

 

[JohnRambozo]

Thanks again. You, sir, are a wealth of knowledge.

 

[nerdnic]

No problem! I am excited to hear about your build. Definitely keep us posted!

 

[nagromnewo]

Hi

Here's some inspiration for doing the Moth Minor. I'll probably build one whether you do or not, but prefer to let you be the guineapig.

http://www.rcgroups.com/forums/showthread.php?t=1411847

PS. Did you enlarge the tailfeather any in relation to the full size plane? Models often need the empennage a bit bigger than scale. My Ryan NYP (Spirit of St Louis) is a case in point. I have to keep the speed up on landings because the elevator looses authorty when I slow her down, and then she refuses to flare. I don't know if the full size version shared the same probem, but from what I read, she was a bit of a handfull and some say that was deliberate so Lindbergh wouldn't fall asleep.

Owen

 

[nerdnic]

Owen,

I do plan to build the Moth Minor. I will post a new thread in the next week or so with the details, but the post you linked will help a lot. Thank you.

As far as making adjustments vs scale, so far it is as scale as it can be. I didn't intentionally make any size changes vs scale. All control surfaces etc are as close to scale as I could make them. If this causes flight issues I will adjust and try again.

I am in complete ailment with your thoughts on the potential loss of authority/bad tendencies that can occur when flying scale proportions, though. My thoughts on this plane were that because it was originally a 'trainer' the surfaces would have been larger than normal and so a scaled down version might be 'just right.' That was my thought process at least, time will tell.

 

[JohnRambozo]

I'm looking at the printed plans now (great job on those, btw) and the control surfaces look plenty big to me. There is more surface area on any one of the control surfaces than on the spitfire. I don't forsee any loss of control on this one.

nerdnic, do you not overlap your wing spar in the center like the spitfire design? I had a gust of wind bend the wings in half on my spitfire even with the overlapping and heavily glued spar. I'm making a new spitfire wing with a modified foam spar that overlaps twice where the spars join together. Maybe I didn't have enough glue where the center of the wing touches together.

 

[nerdnic]

I don't use that thechniqie because I add an aluminum spar in my wings. I can add it to the plans if others would find it beneficial.

For now make sure to use a lot of glue and tape the seam really good. Another thing to note, this wing has only a little dihedral right now, you're welcome to increase it if you desire, since I don't know how she handles yet I decided to start with less rather than more.