StanDouglas

Are the Balsa USA cub struts bass wood or do they have some sort of inner structure? Did they include hardware?
Got my landing gear done. It may be a little springy; I consult with some of the flyers at my field, I can always add a couple of more layers.
I made it with 5 layers of 1/32" plywood sandwiching layers of fiberglass and carbon fiber. If nothing else it's pretty.

Bobt2

My Feedback: (4)

man, they look good. i wish i had that kind time. as to the struts, the balsa usa are solid shaped, bass. i slotted the ends and made the fittings as per the hostetler plans.

Tony Hallo

Interesting landing gear, have you used this construction before?

StanDouglas

This is the first attempt at this method for a landing gear. Here's my source:
http://www.airfieldmodels.com/inform...gear/index.htm

I wet the wood parts and clamped them over night before hand to pre-shape them prior to laying up the resin. It gets a little messy clamping every thing down.
I faced the jig with milar to keep the epoxy from sticking to it and used a strip of milar across the top layer too.

Stan

StanDouglas

I started on the molds for fiber glass wheel pants. I had no top view of them in any of my plans so I studied pictures of the full scale aircraft. One thing that I noticed was that the real ones were much more pointy than the Holstetler planes.

I made the parting plates and joined them with rubber cement so they would separate after being shaped.
These templates still had the rather blunt nose as per the plans.


After shaping them and making the nose sharper..


Here they've been separated glued to a plastic mat and a dam of foam built around them.


Tomorrow I'll pour the hydrocal to make the mold. I also cut 36 5/8"x4"x14-15/16" blue foam blanks for the wing ribs. I only need 24, but that's how it worked out.

Cheers!

StanDouglas

Here's the mold. I still need to give 3 separate coats of epoxy, 3 coats of wax and mold release before I can lay up composite parts. I am using the methods described by Terry Luckenbach in his video "Composite Molding Made Easy".

Bobt2

My Feedback: (4)

would you believe i flew with terry, back in the late 80's thru early 90's in sailplane contests. he had beautyful glass sailplanes.

StanDouglas

Is the Super Decathlon airfoil available anywhere in a CompuFoil or cad format?

I learned a lot from Terry's DVD. Glad I bought it.

StanDouglas

I finished cutting out all the formers and have built up the sides FA and FB. From the plans I cut out F2, where does it go? I don't see it in any of the pictures in this thread.

Bobt2

My Feedback: (4)

f-2 is just showing a fuse cross section, theres no former per say

StanDouglas

I got busy and framed up the fuse. Not too many mistakes! The ones I made will be covered up by 1/8" sheeting. Took me awhile to figure out ho to pull the side together evenly. I finally wound up making a template out of 1/4" ply (cheap stuff in 4' x 8' sheets) of the top view inside from the fire wall to F4. This kept every thing square and true.

The first photo shows the templates glued to the balsa before cutting them out. The second is with the fuse pulled together and the two F15's aligned with the fuse center line, but not glued in place. The first stringer on the nose is crooked because one of my cuts was off. It's the same on the other side as well, but will be covered up by the sheeting.

StanDouglas

Any suggestions on how to rout out F16 and F17 for the wire? Never mind I got it. Used a combination of a grout removal tool and a Dremel tool with 2 disks to get more widrh.

StanDouglas

Pretty much have the wing supports and the wire sorted out and installed. The wing I am going to build has 5/8" blue foam for ribs and I am planning to cut the dihedral into the wing by elevating the tip 1 5'8". This will give me 2 deg. The center section will be cut flat and a card board tube and aluminum tube used instead of the spar construction. My concern is the center section that attaches to the fuse. I want this to be removable so I can access the cabin area for installation and maintenance of equipment.

The J bolts seem rather awkward to me especially with the addition of a wing tube around the CG. It seems like it would be difficult to remove the J bolts at F14 as the nuts are behind J14. What I am thinking of doing is adding a J13a in front of the wire and a J14b behind the wire with blind nuts. These new formers would be permanently attached to the fuse and the structure wires. Then the center wing section with the wing tube would slide in between the new J13a and J14b and attached with hex head bolts. F13 and F14 would end at the center section outer ribs and not continue into the wings.

I have made a drawing. Does anyone have a better solution?

In the drawing the F13 area should have dotted lines for the new former, F13a as it is behind F13 in the drawing, but I got tired of stumbling around in Paint Shop!

Cheers,
Stan

StanDouglas

I made a .cor file for the Hostetler airfoil. It is not the NACA 1412 that the full scale uses. The .cor coordinates that I made exactly match the Hostetler plans. If you have CompuFoil it will in put directly to Eric Sanders program and into Profili. Both programs print out the identical template. I just like the CompuFoil one because it prints the hot wire ramps. I used formica to make my templates.

The forum won't let me upload the .cor file, but if anyone would like a copy send me a note.

StanDouglas

Finished most of the wing center section. Note the missing wing ends of F13 and 14. Instead there is a 3/4" whole for the phenolic wing tube.


Where do you find J-bolts small enough for 1/8" wire? Or do you make them out or threaded rod or something?

StanDouglas

Layed up and then pulled the first 2 halves of my wheel pants last night. Ready to joint the halves and lay up the next one.
The wheel is 3 1/2" for a1/4 scale.

StanDouglas

I'm trying to figure out a minor detail on this Holstetler plan; the J-bolts. Did everyone fabricate their own J-bolts? How or where is a source?

ludfleet

My Feedback: (10)

Hello stan, When I was at that point with my 33% I couldn't find small Jbolts. So I made rectangular shaped sheet metal brackets with a (V) form in the middle to trap the wire. I liked the idea of the J bolts just couldn't find small ones. Joe

Constrictor

My Feedback: (46)

Is a 150 engine too big for the 33%?

StanDouglas

Alright, I made my own J-bolts out of #8 2 1/2" bolts, cut off the heads used a torch to heat and then bent them. Filed out the inside of the bend to 1/8". Seems to work ok, strong. I thin I'll use 3 on each wire. Also finished joining the wheel pants after pullin parts from my mold.

StanDouglas

The right wing is started. The wing tube is parallel to the jig and the tip is cut 1 5/8" higher than the root template to give the required dihedral.
Root end

wing tip end


Looking at some of the photos posted in this thread it looks like some of the builds did not use 2 degrees of dihedral. Is 2 deg. too much?
From trig, if I remember right:
Sine(a) = Opp/Hyp;
sine(2) = opp/48";
.034899 = opp/48;
opp = 1.675152" or 1 and 5/8"


Stan

ludfleet

My Feedback: (10)

To the 150 engine, Yes It's too big, Never heard of enyone trying this engine on the 33%. A100cc would be just fine.

StanDouglas

Engine and mount on a 53cc twin are 6.75 inches to the prop hub face from the firewall.
2 degrees down thrust and 2 degrees right thrust.
Tan(2) = side opp/side adj. (Remember SOHCAHTAO! )

.03492=opp/6.75"
opp= .23571"
That's about 15/64" (64 x .23571)
Set the mount to the left 15/64ths and up by 15/64ths to get right and down thrust and have the prop hub centered in the cowl where it exits.

GerKonig

Today I purchased a built, twice re-painted old and shabby looking used Hostetler Decathlon (30% size). if anybody wants to sell the used plans, please let me know.

My plan is to take off the covering, check the structure (it looks good), paint again inside the cabin, and cover with Century 21 fabric. Possibly install some lights. It had a Z61, so I most likely will install a Z61.

I will need a couple of days to read all this thread...


Gerry

Bobt2

My Feedback: (4)

sorry not to respond sooner. i,m also trying to finish my 1/3 super cub. i got my j bolts from sig mfg. i don;t know about the 21st century but i,m covering the cub in solartex from balsa usa. wow is this stuff great. goes around curves easily and very low heat.when the cub is covered, i,ll use this stuff on the decathlon......