Glad your enjoying it Mark. The techniques are a mix of things I've learned over the years. Actually I am a bit rusty as I really haven't built a balsa kit in a few years, so some of the joints aren't as nice as I would like.....but that's what covering is for

If you want to try your hand at a balsa build, and I think you should , do yourself a favor, and pick up a Stevens Aero (http://www.stevensaero.com/) kit at Toledo, or at the very least talk with him. Great guy and he makes some of the nicest balsa kits out there. Instructions are top notch too. Great for a first time balsa build. When my daughter was 8 she built the Diddle bug all by herself, well I covered it, and installed the electric goodies. This was the first( and sadly last) plane she built, but had not problems. I did an article for RCModeler (a plane so easy to build, even an 8 year old can do it) that they were gonna publish, but the magazine folded before it was published.

Another of my favorite balsa kit manufactures is mountain models, although I haven't built one in years...(http://www.mountainmodels.com/) Last time I built a Mountain Models kit was when a guy named Doug owned it, and they too were top notch. I hear the new guy has continued the tradition.

 

Thank you for the tips. Just browsing through the planes on stevensaero and I instantly fell in love with the puddle bug!

I will have to get one of these, and try my hand at a balsa build
Thanks again for the great info
Mark

 

But ya thought I forgot about this one, huh?

Anyway where did we leave off... Oh yea, wing is basically built...Need to add the leading edge. Original used a dowel, but I was having problems cutting the 2/3 circle in the LE, so I just made the LE a 1/2" square. Not having any 1/2 balsa stock, I laminated some 1/4" stock I ripped to 1/2 inch. Not wanting to waste any, I made scarf joints for the short pieces. Some tape holds it on while the glue cures.

After that was dried, the LE was sanded to shape. Then tragedy struck..... Those of you who saw the Pronto at Toledo may have noticed the one side of the fuse had some war wounds at the front. While drilling the holes for leading edge pegs, the drill bit decided to go berserk..... I have never seen anything like it. And this was the night before I was leaving for the Toledo show with the Pronto.... Anyway a little CA and lightweight spackle and all was OK.

I added some scrap ply to help secure the LE pins, and some scrap balsa around the area so the covering would have something to stick to.

Final touch was to add some scrap 1/16" ply to the TE where the wing hold down bolts will go. Attached files

 

When I built the canopy, it some how got a warp in it... No worry. Just douse with 90% rubbing alcohol, and wrap with an ace bandage. When dry remove the Ace Bandage, and it's now nice and flush....dang,just realized I don't have a pic of it un-twisted.

Attached files

 

I didn't get a CU pic of the sheer webs, but for those not familiar with them, the are added with the grain vertical joining the top and bottom spars. If you check the other forums you will get 1001 reasons why they should be between the spars (like an I-beam) and 1001 reasons why it is OK to glue them to the Outside of the spars. I've been gluing them to the outside of the spars for as long as I can remember, and have yet to have a wing failure... and I've been known to give a plane the stress test in the air.....just make sure the grain is vertical. May seem counter intuitive, but you are adding strenght by stopping the spars from compressing.

Anyway first pic is how I cut them on my band saw. I can make a whole wings woth the perfect size with scrap balsa in seconds.....

Next pic shows all the parts ready to go. If you look close, you can see the shear webs in this shot.

The original used a big block of balsa to carve out the head rest. I hollowed mine on the original, but decided to go with good old foam for this one. Once carved, and sanded, I filled the "grain" with some watered down super lightweight spackel ( the kinda stuff where the tub feels empty when you buy it). I added just enough water to make it like pancake batter. Once sanded I added 2 layers of 1/2ounce cloth and applied with Water Based Poly-U.
When they poly was cured, I painted on another coat of watered down lightweight spackle, and sanded. Smooth as a new born baby's behind. (no pic yet) Attached files

 

As I made the fuse side from 1/16" balsa, I didn't exactly trust the tail area to be sturdy enough so I decided to add some tri-stock reinforcement. Instead of just slapping it on there, here's what I do when adding the tri- stock. Weight savings is negligible at best, but I think it just looks better.

I use a ball cutter in a drill press with a scrap piece of lumber as fence, and make the cuts progressively deeper by moving the fence closer, and raising the table on each pass.

More to come... Plane is covered, and I need to make some push rods... I may make new gear, or I may just use the gear from the old one. I pulled it out of the rafters to take a picture with the 2 of them together, and boy is that old plane ratty.... Attached files

 

looking great Dave! Can't wait to see her completed shes going to rock!
BTW Love the paintbrush idea!
Mark and Trish

 

Thanks Mark...Did you ever talk to Stevens Aero at Toledo?

Getting closer....

Tail feathers mounted. I made a slight mistake when designing, cutting, covering the rudder.... Notice a problem with the first pic?

Fixed in the second Attached files

 

I used toothpicks as LE pins for the cowl....magnets in the back. Notice 6/32 bolts used to receive the magnets. They are threaded into hardwood blocks so the mate with the magnets exactly. I can never seem to get this right any other way.

Edit: Actually last pic...forgot to add until the end...Next pic is it all covered and ready for the incidentals. Motor has been ordered, and should be here before too long. Looking to get about 200-225Watts out of it.

Next up are a few pics of the new Pronto with the old Pronto I flew for quite a while. I think it last flew in 97 or 98. Can you guess which is which?

I took the Landing gear off to weigh the empty airframes... Old one was 26 ounces, new one is 15 ounces... Hope I didn't make it too light

I also decided to just use the old gear... you know keeping part of the old gal flying.... Attached files

 

Here's are some techniques I used on this build. Hopefully they help on a future project of yours.

I usually cut my own tri-stock. A lot cheaper, and I can get the sizes I want. Here is how I do it with a jig I made for my band saw. Guide is lowered for real cut, left up for photo.

To make the windscreen I first made a few paper template to get it just right. Then I transferred it to a box that a Spektrum receiver came in. I knew it would come in handy

I used this method on the original to make the wind screen combing, so why not use it on this one too. Get some wire of the right color and slit the insulation long wise. First straighten the wire the best you can. It is easier than it seems.

Then glue to the wind screen. They sell canopy glue for something like $6.00 an ounce. I have been using Weldbond for YEARS. It is a few dollars for 4 ounces at the hardware store. It even smells like canopy glue. This bottle was purchased in Jan of 97 (I mark stuff like this w/ the date of purchase just to see how long it lasts). There is still half left, and it is as good as new.... unfortunately the bottle shatter when I picked it up. Hope the transfer container keeps it. Attached files

 

Well I flew the Pronto this weekend. I need to make a few tweaks.

Original plane used an 8" or 9" prop, I have an 11" prop on this one. Problem is I used the gear from the original, and the plane will not sit level without hitting the prop. Take off was OK, as with all the power I had ( 250 watts measured after a 10 minute flight) it lept off the ground with out having to get it up on the step. Landings were fine too as it is so lightly loaded, I was able to land a little nose high. I do like the way a plane looks when up on the step during a touch and go tough, so I'll be making new gear as touch and gos were another favorite with the original. A bunch of us had them at the time, and in the evening we would do nothing but touch and gos in formation. Cools stuff.

I think I need some right thrust too. Original had about 3 degrees down ( which I built in easily thanks to the precision of the Phlat Printer ), but with that big 11" prop, it is behaving weirdly with motor on. Motor off, or low idle it is totally different plane....a lot like I remember the original. With the 8" prop I used to fly the glow one on, it didn't seem to matter the throttle position.

Almost augured it in on the first flight. One of my favorite things to do with my old Pronto was a flat spin. It would go in easy enough if coaxed, but getting out was another story. A few times it would land on the runway with the motor still running if I failed to get it out. Anyway with this one, I was NOT over the runway, but the woods. The old one used to require down elevator, opposite rudder, and full power to get out in about 3 or 4 rotations. Well when I did that with this one, it just kept spinning, and spinning, and... as the ground was getting closer, I chopped the throttle ( only so many things you can try with a 3 channel plane in a spin). The spin slowed, and 6 turns later, it finally dropped it's nose. I eased up on the elevator at that point, but kept opposite rudder; about 3 more spins it stopped, and I was able to pull out....about 3 foot from the tree tops Good thing I started really high, and it fell really slowly when flat.

So I have a few more things I need to tweak, and then it should be a welcome addition to my fleet.
I'll post some in-flight pics when I get home tonight....if I remember. The boss (AKA wife) has a new project for me that just arrived about an hour ago, and it's filling the drive way.....

 

Congratulations on the test fight!!
Sounds like a few more tweaks and you will have it just the way you want it.
I was thinking about the the right angle of the thrust line, I bet you could design that into the model so that you wont have to shim.'
Great job!
Mark and Trish

 

Finally getting around to posting inflight Pics.... I need to get a new photographer for the inflight stuff

New gear is bent so I have better ground clearance. Still didn't change thrust angle as the flight characteristics would indicate left thrust is needed, and that just ain't right I think I'll try a smaller prop first. Attached files

 

AWESOME!!!!
She turned out great!
Mark and Trish