Francherized Twister

[Chris Fretz]

After looking at the PDF under Construction Details it says Outboard Flap 1/8 wider at the tip than inboard flap. So to clarify this is it saying to make the outboard flap 1/8 wider the whole length of the flap or what?   Saying at the tip I find rather confusing.

While I'm at it under Modifications to original kit it says 3/32 plywood doublers. Then it says Replacement Doubler 1/16 plywood. I'm thinking I'll use 3/32 but is it suggesting using 3/32 or 1/16?

Finally it says to make wing jig blocks to the shape on the plans but I can't see a way for me to make them and all be identical.  So what does everyone use to build the wing? Just flat on a building table?

Thanks
Chris Fretz

[rich gorrill]

Hi Chris, when I modified a Twister ala "Fancherized" I built the wing flat on the table, had no problem, the leading edge needs a lot of sanding to round it off, I left the flaps stock, 1/16 stock doublers, increasing to 3/32 cant hurt. I did extend the fuselage 1 1/2 inches as per Danny B. and I did add 1/2 ribs in between reg. ribs. I use an LA 40 which is plenty of power.
worst problem I found is the landing gear. The wire gear in the kit goes into a bushing and uses little plastic clips. If I do it again I would use alum. gear like Brodak and RSM supply in their kits. Good luck.


Rich

[Tim Wescott]

Finally it says to make wing jig blocks to the shape on the plans but I can't see a way for me to make them and all be identical.  So what does everyone use to build the wing? Just flat on a building table?

Cut them a bit oversize, stack them, sand them.  Tacking them together with CA will help.  Sanding them square is a chore, but can be done.

I have some 1 1/4" square finish wood that came with my house, I just tucked that under the TE, like in this post.

[Steve Helmick]

"After looking at the PDF under Construction Details it says Outboard Flap 1/8 wider at the tip than inboard flap. So to clarify this is it saying to make the outboard flap 1/8 wider the whole length of the flap or what?   Saying at the tip I find rather confusing."


It means to make the outboard flap 1/8" wider at the tip. Root chord would remain the same, so the taper is different. Adding area to the outboard flap is a common fix to older designs, to stop "hinging" with the correct tip weight. From my experience, it won't take a lot of tipweight, what with the outboard engine/tank weight.  Steve

[Chris Fretz]

Hi Chris, when I modified a Twister ala "Fancherized" I built the wing flat on the table, had no problem, the leading edge needs a lot of sanding to round it off, I left the flaps stock, 1/16 stock doublers, increasing to 3/32 cant hurt. I did extend the fuselage 1 1/2 inches as per Danny B. and I did add 1/2 ribs in between reg. ribs. I use an LA 40 which is plenty of power.
worst problem I found is the landing gear. The wire gear in the kit goes into a bushing and uses little plastic clips. If I do it again I would use alum. gear like Brodak and RSM supply in their kits. Good luck.


Rich

Thanks for the info,  I remember your name but I can't place a face!

[Chris Fretz]

"After looking at the PDF under Construction Details it says Outboard Flap 1/8 wider at the tip than inboard flap. So to clarify this is it saying to make the outboard flap 1/8 wider the whole length of the flap or what?   Saying at the tip I find rather confusing."


It means to make the outboard flap 1/8" wider at the tip. Root chord would remain the same, so the taper is different. Adding area to the outboard flap is a common fix to older designs, to stop "hinging" with the correct tip weight. From my experience, it won't take a lot of tipweight, what with the outboard engine/tank weight.  Steve

Well that makes a lot of sense! Guess I was thinking too much about the 1/8 and tip! Ill make my flap like that.

[rich gorrill]

Chris, I'm with the Philly Fliers, we met at Bernie's contest and than at our contest at Neshaminy & Benjamin Rush.

[Chris Fretz]

Chris, I'm with the Philly Fliers, we met at Bernie's contest and than at our contest at Neshaminy & Benjamin Rush.

I think it's coming back to me now!

[Chris Fretz]

Cut them a bit oversize, stack them, sand them.  Tacking them together with CA will help.  Sanding them square is a chore, but can be done.

I have some 1 1/4" square finish wood that came with my house, I just tucked that under the TE, like in this post.

Thanks Tim. I can't really tell what you have going on under the spar, it don't look to be flat on the table.  How did you figure out the 1 1/4 under TE?

Chris

[Tim Wescott]

Thanks Tim. I can't really tell what you have going on under the spar, it don't look to be flat on the table.  How did you figure out the 1 1/4 under TE?

Chris

I can't remember what's under there -- probably scrap bits of 1/4".  I figured out what to put under the TE because that made the ribs roughly level fore and aft, along with whatever I shimmed the spar up with.

Just make it level -- all else will fall into place.

[Chris Fretz]

I can't remember what's under there -- probably scrap bits of 1/4".  I figured out what to put under the TE because that made the ribs roughly level fore and aft, along with whatever I shimmed the spar up with.

Just make it level -- all else will fall into place.

Would I benefit from building up the stab and elevators like you did or just stay with my 1/4 balsa pieces I already rough cut out?

[Tim Wescott]

Would I benefit from building up the stab and elevators like you did or just stay with my 1/4 balsa pieces I already rough cut out?

When I built that plane the kit wood was rock hard and had strange grain patterns, and I didn't have any decent wood to replace it with.  If I did it again I'd use reasonable-weight sheet.