What could be done to reinvent the Affordaplane to a more homogeneous project?

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

FritzW

Well-Known Member
Log Member
Joined
Jan 30, 2011
Messages
3,886
Location
Las Cruces, NM
It's all done on a CNC router. It takes about an hour to cut all the ribs for one wing panel and another hour to cut all the little diagonal stiffener sticks (8 per rib). ...but it only takes about 5 minutes to put a rib together.

As much as I like working with wood, I still think XPS foam ribs are the way to go for an APlane or Afford-A-Storch. It's about 1/10th the cost of aircraft ply and, more importantly, it's easy to find.

The wing is easy. What really needs to be sorted out is the fuselage. If you use finesse instead of brute force I think you could save a whole bunch of weight without adding a whole bunch of complexity.
 

Victor Bravo

Well-Known Member
Joined
Jul 30, 2014
Messages
7,236
Location
KWHP, Los Angeles CA, USA
As much as I like working with wood, I still think XPS foam ribs are the way to go for an APlane or Afford-A-Storch. It's about 1/10th the cost of aircraft ply and, more importantly, it's easy to find.
Did you ever complete all the tests or experiments you wanted to do with XPS ribs and strips of plywood or door edging or wood trim glued on as caps?? My initial guess is that the attachment of the XPS foam to the (wooden) spar is going to be the weak link in the chain... did you come up with some way to strengthen that joint easily?
 

FritzW

Well-Known Member
Log Member
Joined
Jan 30, 2011
Messages
3,886
Location
Las Cruces, NM
Just about anything that works well on the foam will work well on wood, at least from what I've seen.

The clear winner (so far) for gluing on the cap strips is 3M 30NF Fastbond. I'd also use it to glue in the doublers at the spars. Then I'd probably use T-88 to actually glue the ribs to the spars. ...maybe Great Stuff spray foam if I could figure out to use it without making a huge gooey mess.

Remember this idea (Carson Spars)?
Ranger ribs4  2.JPG
Ranger wing3 3a.JPG
 

Victor Bravo

Well-Known Member
Joined
Jul 30, 2014
Messages
7,236
Location
KWHP, Los Angeles CA, USA
Don't you need to tie in the loads from the spars to the rib caps? I don't know how exactly much load there is in between those two parts, but raw foam in between two stiffer/stronger pieces gives me the willies.

Love the old Top Flite leading edge though :)
 

FritzW

Well-Known Member
Log Member
Joined
Jan 30, 2011
Messages
3,886
Location
Las Cruces, NM
Don't you need to tie in the loads from the spars to the rib caps? I don't know how exactly much load there is in between those two parts, but raw foam in between two stiffer/stronger pieces gives me the willies.

Love the old Top Flite leading edge though :)
Tieing the caps to the spars wouldn't really make any difference. They take the tension on the edge of the ribs when the rib trys to bend. The caps might as well be strapping tape, like the strapping tape you put on the bottom of foam model airplane wings. The only advantage to thin, wide wood strips is they also make the ribs very stiff laterally.
 

erkki67

Well-Known Member
Joined
Feb 18, 2010
Messages
1,971
Location
Romont / Fribourg / Switzerland
Is such a foam rib construction also viable with a tube as a leading and trailing edge construction?

and for the diagonals insertion, the 2 part plywood construction was ideal, could such a 2 part foam construction be the answer for this problem?
 

erkki67

Well-Known Member
Joined
Feb 18, 2010
Messages
1,971
Location
Romont / Fribourg / Switzerland
7185AC68-B29A-47EE-B331-25474ACD7B4A.jpeg


No, its not going to be the fuselage, or yes some kind of. This square wooden sticks are going to be built up to a mock-up fuselage. I’m going to check the sizes and fitting!

a friend of mine came up with all the lengths in millimeters and all the angles for the Affordacub layout.

For the Gussets I’m going for this wooden with simple round plywood disks and cut them down once the glue is dry.

for fitting, this should be plenty strong!
 

erkki67

Well-Known Member
Joined
Feb 18, 2010
Messages
1,971
Location
Romont / Fribourg / Switzerland
Yep, the idea is to have a straight upper longeron, for the fuselage.

concerning the wings, I’m not sure yet, but here in Europe they use quiet often 2017 alloys for wing spars, so I’m checking what’s available for those alloys .
 

erkki67

Well-Known Member
Joined
Feb 18, 2010
Messages
1,971
Location
Romont / Fribourg / Switzerland
Just about anything that works well on the foam will work well on wood, at least from what I've seen.

The clear winner (so far) for gluing on the cap strips is 3M 30NF Fastbond. I'd also use it to glue in the doublers at the spars. Then I'd probably use T-88 to actually glue the ribs to the spars. ...maybe Great Stuff spray foam if I could figure out to use it without making a huge gooey mess.

Remember this idea (Carson Spars)?
View attachment 95554
View attachment 95555
what about using a tube as a leading edge and the rear spar just in front of the ailerons.
 

bob

New Member
HBA Supporter
Joined
Feb 12, 2020
Messages
1
Location
Columbia Station, Ohio
Hi Guys, this is my first post on here. I have been following this thread and others just trying to learn as much as I can about home building. A few pages back there was a video posted about a tandem AP. I watched the video a couple of times trying to see what the guy modified to make it a tandem. I subscribed to his channel and there is about a 11 min. video of his build that shows most of what was modified. Full VW engine, dual wing tanks, extra supports under the fuselage. A-Frame landing gear with bungee springs are just a few of the things I picked up. Couldn't understand a word they were saying as it's all in spanish. here is a link to the video. Maybe there is someone on here that could translate it. Thanks for the education.
 

galapoola

Well-Known Member
Joined
Jun 4, 2017
Messages
68
Location
NJ
Click on the closed captioning icon "CC" then click on the gear next to it, select auto translate and choose English.
 
2
Top