2017/2018 Balsa Build Along, SIG HOG BIPE ELECTRIC CONVERSION

[nhk750]

Lower wing construction continues

I have been working on the lower wing every day a little bit, but life is busy right now with Xmas and all. I had a few problems trying to razor plane the trailing edge as the balsa strip was very hard wood and I finally just sanded it to shape, after dinging up the sheeting and breaking the trailing edge sheeting with my gorilla hands...So I repaired the sheeting and still need to fill in some dings and gouges, but it is coming along. The next step is wing tips, then I will install the updated servo mounting kit. I will detail document for others the installation as the directions kind of suck and posts on the internet have not done a great job at explaining how to do the mod.

P-3, interplane strut mount, installed and rough sanding of wing done.

 

[nhk750]

Aileron bays

Working slowly on the aileron bay and came across a few issues. The addendum to the directions for the aileron bay installation has you install the cap strips in step 35 off center to accommodate the aileron bay rails...oops, I didn't read the extra sheet of instructions as I thought they started on step 39. It really didn't make a difference though as I just trimmed the cap strip back to the W-2 rib and it looks great. I may even do this on the other half of the wing to make things the same.



The other issue is the bay rails, they have you install the rails and then sand them to fit the W-2 ribs. I got the thinking it would be easier to pre bend the basswood rails then install them and sand to fit. So, I made a jig by tracing the W-2 rail and cutting it out with a jigsaw, then soaking the basswood in warm water and clamping to the jig overnight to warp it. Seemed to work great and now just a little bit of sanding to fit. I did learn to put some scrap wood on the basswood to prevent the clamps from smashing it though.

Making the jig for bending/warping the basswood to fit the contour of the W-2 ribs.


Clamping the basswood rail to warp it after soaking with warm water for an hour or so.


Fits good and just a little sanding to fit now needed instead of a lot of sanding on a fragile frame.

 

[MKolm1911]

Very nice airplane I have one has a super tigre 75 in it and my dad has one with a COMO 60. That plane is easy to build and easy to fly it’s a true sport biplane.

 

[nhk750]

Aileron bay update

Quick update, the bay rails worked out great and pre warping definitely made the job easier!

Used epoxy to glue rails in for max strength.


Just a little sanding needed to make fit perfectly after pre warping rails to fit W-2 ribs. Sanding was performed prior to gluing in.

 

[Joker 53150]

Well done. Tricks like that take some extra time, but they save you a lot of effort in the long run.

 

[nhk750]

Aileron bay finished

Finished up my first aileron bay and it came out great. Here's some pictures.

Epoxied the servo supports on and reinforced them with some baswood scraps I cut and epoxied in also. I have read a few guys said to make sure these supports are strong as they can fail if not. I also ran some small servo screws into the supports from the cover side as recommended by a few guys.


Hitec HS-485HB servo mounted.




I had to cut out the basswood rail back side of servo a bit so the servo would fit.


Everything fits good.

 

[nhk750]

The lower wing work continues

I'm about half way through the second half of the lower wing, then I will join the halves.

As I build more wings I am learning new techniques for making a very true wing and also do less damage to the balsa by using scrap wood to spread loads and shim things.

 

[nhk750]

Update

I am still grinding away at building the second half of the lower wing, got the sheeting glued with Titebond II today and now I can get moving on getting this bottom wing finished. Our bathroom remodel project has been taking precious build time away from me...

Sheeting drying with some weight on it...

 

[nhk750]

The works continues, I have found new ways to use my magnetic clamps and jigs from building two wings now. I guess your only limited by your imagination when using magnets, magnetic jigs, presses, clamps and lead shot filled containers and bags. So far not one pin was used on this build and I don't plan on touching any pins now that I have learned the art of magnetics. It is so much easier!

Gluing trailing edge on.

 

[nhk750]

Update

I have been working on the lower wing halves a tiny bit each day, and finally have two wing halves. Just need to add wingtips and epoxy/glass the two halves together now.

 

[Dalton10E]

Looking good man!
I did a hog bipe electric conversion last fall and it is one of my best flyers.
Make sure you have strong landing gear, and plenty of power. these suckers get heavy!

 

[nhk750]

More bottom wing progress

Sig has you tack glue the wingtips in place with CA, then hold them in place by hand while wicking CA into the joint. Well, I don't like doing that as I think CA is not the greatest thing to use on ply and I prefer Titebond II. I used my Airfield model's face clamps, attached to the magnetic jigs, and they did the trick perfectly. I applied a generous amount of Titebond then positioned the face clamps to hold the wingtip in the perfect alignment so it could dry, then used a cue tip to remove any excess that dribbled out. Fun stuff! Soon I will join the two halves and then there will be one bottom wing.

 

[nhk750]

Sheeting wingtips

Here is another detailed step. Someday someone else will build the Hog and thank me for such a thorough build thread...

It is the first time I have sheeted a wingtip so I am not sure how this will go. I looked at other people's pictures for the Hog Bipe build and it looks like they did it kind of this way too. I used Titebond II on the wingtip then applied the sheeting, then put some scrap balsa over the top of the sheeting, cut to fit, so the clamps wouldn't damage the sheeting and clamped away. Hopefully this will work. I will see tomorrow after the glue cures as I don't want to rush this step. If this works then I can sheet the last three sheets faster.

 

[nhk750]

Came out great, just need to trim and sand to shape. I used Willsonman's technique of spraying one side with ammonia to help bend around corners.

 

[rockyboy]

That looks great! Very nicely done sir!

 

[nhk750]

When I glued on the wingtip sheeting on the other side I found the clamps would not work and just slipped off. So I used some medical tape and painters tape to hold it on tight. Seemed to work fine as you can see the finished product on the other wing.

 

[rockyboy]

I agree - when in doubt with balsa clamping, good old masking/painters tape and piling on weight with shot bags works wonders too. I need to try the flexible medical bandage idea (like ankle wrap) though. It's springy enough and slightly sticky to itself which seems like a great combo - as long as it doesn't get glued to the balsa

 

[nhk750]

The medical tape, amazingly, does not stick to Titebond hardly at all, I'm not sure about CA though. It's almost like it's made for building airplanes.

 

[rockyboy]

And one more good reason to slow down and use Titebond!

 

[nhk750]

Got the wingtips done and ready to epoxy the bottom wing together. I think the tape is the way to go as the side of sheeting that I was able to clamp on is distorted a bit. It's a learning process, but it will pass inspection. I will only use tape on the top wing when I install the wingtip sheeting.