Mini-Sized B7A2 "Grace" Build (Based on mini corsair)

[Polkadot]

After totaling my mighty mini corsair, I decided to rebuild it as something with a little more flair. So I picked an underappreciated plane with a similar layout to the corsair and decided to start on an Aichi B7A2 Ryusei (codenamed "Grace"). The codename says it all as this inverted gullwing naval bomber is really beautiful and has great proportions.

I haven't quite started building yet but for my first prototype I'm going to elongate the mini corsair fuse by around 50% to make up the longer, thinner fuse of the Grace. It's hopefully going to wind up roughly the same scale as the mini warbirds but a bit bigger since it is a bomber.

 

[Polkadot]

After a good sleep, I've realized that I'm massively overscaling this, as the full scale grace is only 12% longer than the corsair, rather than 50%. I'm going to look at some 3 view drawings to scale the width and height of the fuse to the corsair, and then scale it to that, as my electronics are a tight fit even in the corsair, so going thinner is not really an option.

EDIT: After looking at some 3-views, If i want the same fuse width and height I need to scale the grace's dimensions up by 10% and use that to scale the length

 

[Polkadot]

I've been slowly plugging away at the design, and I've come to realize that while I can base the general layout of the parts on the corsair, I really need to do more than change the proportions to get this looking like the Grace. I've decided to do more planning and get all the parts sketched up in SketchUp (pun intended) and It's all ready looking better than the extra long corsair fuse that I initially made.

Overall the size is going to be 24" long with a 31" wingspan, the wing will go into the fuse before the anhedral and dihedral are worked in, as the top and bottom of the main fuselage box conveniently line up with the lowest part of the gullwing and the wingtip height. There will be formers with posterboard over them both on the top and bottom, and I'm going to try to implement a mini mustang style hatch.

Gonna keep at it and eventually it'll work

 

[Namactual]

Looking good so far bud. I can't wait to see the build.

 

[Polkadot]

Looking good so far bud. I can't wait to see the build.

Thanks, I can't wait for the build either. Working with foam is a lot more satisfying than working with pixels.

Progress is being made.

Starting to nail down design elements, but I'm not happy with how flat my top formers are compared to the front view. So it looks like I'll have to lower the box section relative to the overall fuselage, which means making the side pieces more like the corsair where the bottom tapers up and the top is raised above the box for the H. stab.

Much better. It'll make the wing a little bit in the way of the hatch opening so I'll need to fiddle with the cutouts in the top plate, but it's nice to see some progress.

 

[rockyboy]

Looking good! Don't be afraid to make the tail surfaces about 10-15% bigger overall as that can really help with handling characteristics - especially yaw control. Air doesn't scale down gracefully

 

[Polkadot]

Looking good! Don't be afraid to make the tail surfaces about 10-15% bigger overall as that can really help with handling characteristics - especially yaw control. Air doesn't scale down gracefully

Thanks for the encouragement and the tip, Though the tail surfaces on the full scale grace are pretty chunky so I'm probably going to try scale and then make them bigger if I have control issues.

On to the update, I've been feeling a little bleh lately so I haven't made much progress, though I have reworked the hatch to my satisfaction.

The plan is that the hatch will have a tab at the front and a tab with a hole at the back. the front tab will slide into the center slot up front and nestle under the cowl, and then the back will be held in by a BBQ Skewer.

I think next up is the wing, so onwards and upwards!

 

[Mark P]

Can't wait! I've been looking for some dive bombers to go with the mighty minis, there already is an A6M2 so why not complete the picture?