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Jan 01, 2020, 07:07 PM
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Pacific Ace 74 inch


Crashed a trainer last month. My fault before I even started the engine. Was using my old Futaba 7uaf on 72 mhz as I was out of 2.4ghz receivers.
The plane was a pretty touchy on the controls last time out. So I added some expo while waiting in the pitts. Unfortunately I added + expo, not -. What a wild ride to I finally found the ground. And that was that for that bird.

I haven't' had much opportunity to fly since around 1997. To say I am rusty would be an understatement. I have been blessed to find great club about 45 minutes away that caters to vets. 40$ dues, 7000 feet of runway (yep SEVEN THOUSAND). It's an abandoned military runway. But it is the opposite pattern to what I learned and did probably 95% of my flying in. So I do need to build my skills again and get lots of practice with this counter clockwise pattern.

So I wanted a replacement Trainer. And it was just something I sort of just threw together. But I did not want to just build a new version of the one I had crashed. The wife liked the transparent orange I had covered the wing with (what I had on hand). So the replacement seemed it should likewise have transparent covering. So my thoughts turned to Pacific Ace.

I built Pacific Ace 74 inch once before while my ship was swinging on the hook off the coast of Kuwait during the first gulf war (mine clearing). Well I got all the framing done anyway. And then finished it when I finally got home. Learned to fly on it. Did some thermal soaring with it when the engine died. Some fairly long flights.

When the wing survived beyond the fuse I used it for slop soaring. Had some great flights when the wind and slope lift died and was thermalling. Got lots of comments from my buds on the slope.

So I showed my wife the pics I had scanned of the my old Pacific Ace. Showed her the original planes I still have (yellowed and fragile). She loved it. But she loves stick construction anyway.
So that settled it was time to get ready to build a new one. I also just happen to have the plans scanned as well. I tile printed those out and slowly over several days taped them together, but just sections. The Wing the fuse, tail feathers. Much easier to work with.

I hit the hobby shop for some lumber (OUCH$$$) Christmas eve.

Had to make a number of substitutions buying wood, as they did not have what I needed. Bought 1/4" sheets instead of 1/4sqr stick and 6" sheets of 3/32" instead of the 2" sheets I had wanted to buy. But I am blessed with a real nice table saw ) A Delta 5000 series). So I installed my finest blade and went to rip city. Made lots of 1/4sqr sticks and 2" sheets of 3/32" for wing ribs. I then cross cut the 2" pieces into rib blanks. I will stack shape them in one or two stacks later.

I started building with the fuse sides. I did the first one sitting on the recliner sofa with my wife While streaming The New Yankee Workshop. I have a 4' balsa building board. Tools sitting on my laptop next to me. Dog booted from between mama's legs so I got room for the board. Wife's (Windy) tablet on her opposite leg.

So that got one side completely framed up, But that was not going to work beyond that. The second side was pinned right over the first half. Wide transparent tape was put over all of the joints so as not to end up with one double thick side. So for that I worked in the garage. Took a hour for my propane radiant heater to get the garage comfortable enough to work in.

Much of the forward section is spruce. There was no way the bottom spruce stick was going to make the curve. It got soaked in hot water. Then bent and left to dry before gluing. It goes from the firewall to the trailing edge of the wing, and the a 60 degree scarf joint to the balsa back half (epoxied). I found it was easier to over bend the hot wet spruce and let it dry that way. It then sprung back to very close to what I wanted. I was just guessing on how much to over bend it, but i got lucking first try, it really was close. Maybe just a bit over curve. But the vertical and diagonal sticks took care of that.

I, have made some so far minor changes to the structure. I added diagonals every vertical. All of the diagonals are mitered to the vertical and to the top and bottom longerons (correct term?). So there are two miters on each end of the diagonals. Tedious would be an understatement. The plans don't call for that many diagonals. And also I added gussets to every joint, even in between the diagonals. Even more gain tedious.

The gussets have been rounded out. I doubt it saves much weight but it sure does look way better, and they will be visible (transparent covering). Used my dremel tool with a sanding drum for that and a pair of rat tail rasps.

All the vertical spruce joints and the scarf joints are epoxied, the vertical balsa joints are Tightbond 2, and the diagonals are medium ca. All of the diagonals are balsa.

So far that is 4 build sessions. First session with my wife on the sofa, and the rest in the garage. Windy would have been out there with me if we could leave mom unattended for even a few minutes. But mom is 92, senile, virtually deaf and blind, and extremely frail now.
I moved my small disc sander right next to me in the garage. Sure made it a lot easier to fit the parts. And I am real fussy on how tight all of the joints are. Sometimes when the fit was just almost there but not exact, I spun the disc by hand vice turn the switch on so as to take an almost imperceptible amount off a gusset or vertical or the mitered diagonals. Maybe that is a bit anal. But i do believe that it does improve joint strength and beside all of the joints are going to be visible.

Ken
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Jan 01, 2020, 07:14 PM
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Now for some pictures.
First my original Pacific Ace
Jan 01, 2020, 07:19 PM
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And now the current build
Jan 01, 2020, 07:20 PM
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Forgot to mention power plants.
The original was powered with an os .20 four stroke. Really was a cute thing. Enough power to cruise at about 75% throttle.
The current build will use the engine from the plane I crashed. It is an os .25sf.

Oh and this plane is a 3 channel aircraft.

Ken
Jan 01, 2020, 07:22 PM
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Got some work time in today. Fair progress.
All the tail feathers are framed up.
Major task ahead are Building the wing tip bows, framing up the wings, and joining the fuse sides. I will frame up the wing panels on the table saw bed. Nice and true. But only 24" long, so will have to do in sections.
I have been back and forth in my head weather to laminate up the tip bows from thin stock or from sections of 1/4" like I did the tail feathers. to build up the tips I will have to make another 20 minute trip for wood. I will spend more on fuel driving for the wood than the dang wood cost. I drive a F250 diesel pick up. Paying 3.79$ a gallon. Dang me I knew I should have bought one more sheet

Ken.
Jan 02, 2020, 09:17 PM
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BMatthews's Avatar
And so now you'll cruise around at around half throttle..

For next time consider splitting the spruce stick into two or if you can manage to do it cleanly three layers. The resulting thinner sections will easily take the bend and hold them. Even just slitting it along the middle with a thin scroll saw cut is a HUGE help and you can put in a far more aggressive curve easily and safely.

This will be a fun build to watch. Usually such builds are found in the Vintage forum. Hopefully the other balsa builders will find this interesting and try a vintage design of their own.
Jan 02, 2020, 11:49 PM
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Thanks for the tips Bruce and glad you think it will be a fun build.

Yeah I will confess I did not think the spruce bending thru very well. Witch is a kick my own but moment. I've done bending before by laminating thin strips. Works a charm. Heck that even opens up transitioning from one wood to another over a distance and several layers, sort of blend from one to another.

I also wonder if maybe Bass would have been sufficient to substitute for the spruce? Not that I change anything on fuse like that after the fact.
I am considering substituting Bass for the Spruce wing spars that the plans call for. Last 2 or three wings Iv'e made I used Bass for spars and it was very strong.

I am hoping I can get back to the bird Saturday or Sunday. I have had to go off my arthritis meds and Ibuprofen for a minor surgical procedure tomorrow. So no my left hand thump knuckle is swollen like a few wasp had hit it. Can't use that darn hand now, hurts to bad.

The entertaining part of the fuse build will be making the bends behind and in front of the wing for 2 sides to join at the back and meet the firewall at the front.

Ken
Jan 03, 2020, 12:25 AM
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Might be nice if I posted the plans.
Jan 03, 2020, 12:56 AM
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Basswood on a model like this is a fine option for spars or main longerons and the like. It ranks up there with spruce and pine. The trick is to find nice supple springy wood for any of the three options. And that means slow grown examples with closely spaced growth rings. It's the harder winter rings that give the wood the springiness. So you want a good number of them in the parts.

Proper aircraft spruce isn't just sitka spruce. It's selected slow growth sitka spruce. Picked for the high ring count per inch of cross grain.

I've also tried some redwood, local cedar, hemlock and douglas fir. But all of those were far too brittle and tended to almost shatter instead of being supple and springy.
Jan 05, 2020, 06:05 PM
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Well here is today's progress. Not much, but my left hand is still very tender and weak. Wife said no more today.

Well the procedure went fine Friday. My hand actually stopped aching like it had received a hammer blow a few hours before. I asked that they not touch my left hand or even arm. The saw how swollen my hand was and hung a big re sign on my i.v. to the that effect. I thought all was cool at that point. Then they wheeled me into the room for the procedure, And the male nurse reached across me from my right side and grappled my left hand. I screamed it hurt so bad. Then a few minutes later the female nurse on the left reached for my left hand and actually took it by my thumb. Another pain scream and I buried my head while tears I had no control over flowed. She wiped my face and rubbed my cheek. The Dr Order everybody in their to not touch me on the left and to support my left hand on pillow with another blocking it. The Gave me a dose of pain med thru my i.v. Asked how that was, I told him it still was not helping, then gave some more and let's just say I was a very happy camper at that point.

But JEEZE, can you believe just how dense they 2 nurses were? I hope after I was out of the room the DR tore them a new one, but good. No excuse for that.

They DR. said I would need to wait another day before restarting my anti inflammatory again.
So swelling is down. But hand is still not real useful other than as a fancy paper wight. So that is all that will get done for a bit.

So next I have to make the center section ribs that will get the center section sheeting, and the 2 tip ribs.

Then joining the fuse half's and building the wing panels.

Ken
Jan 05, 2020, 08:21 PM
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That's quite the story about your hand ! ! ! ! I'm almost getting sympathy pains just reading it. Here's wishing you heal fast and heal well..... and no more quasi sadistic nurses! ! ! !

When the time comes to erect the sides over a board and pull the sides in I'm sure you'll find the pull to the tail is pretty easy. Just pull them in naturally and evenly so they meet and naturally want to sit at the center line.

I see in the plan link that it looks a bit like the main longerons are to be cracked and glued so they kink at the front and rear of the wing. I'd suggest you ignore that and just flex them naturally to the tail and the nose and maintain full strength through those fairly critical points where the plan seems to want you to crack them.

If the tail is offset when the two rear uprights match then "slide" the joint a little to move the tail so it's over the center line. But if they are out double check that things are lined up and square through the central cabin box first..... just in case... just in case..... If the main box is all good then don't fight with the tail ends to force them to even up. let 'em slide a touch as they want to. or if you can see that one side is fighting to be straight and the other is bending a lot more than the other that'll make the rear ends not line up either. And in that case you'll want to put some hot water on the stiffer side to let it bend so it's even with the other side. If hot water by itself doesn't let them even up hit the wood with your covering iron heated up pretty hot. But don't do this over the glue joints or they may come loose. That's why I'm saying covering iron instead of hot air gun. And in the end if one side sticks past the other by a touch it's nothing a bit of sanding can't fix.

The nose can be a bit of a battle. That's where I'd say use some full strength household ammonia brushed onto the wood for the whole length of the nose longerons. Or use the hot water then hot covering iron after the water has soaked in a bit. They still need to be evenly bent and should be holding the even bend after any special treatments to the stiffer side.

If all this is old hat to you my apologies for hauling it out again.

I've had to use the water and covering iron trick and it worked like a charm Oddly enough not on a stick build like this. A kit I built years ago had one soft and one super hard side. I probably should have just made a new side but instead I put hot water on the outer side of the hard piece. It helped but not enough. I'd done some steam bending around a hot iron for a music instrument I'd made a couple of years before so I tried using m covering iron on the wet wood. It worked wonderfully. I almost keep hoping I'll have to use it again. But apparently i'm too good at matching my wood even when I don't try and I've never needed it again... YET

Again I hope the hand gets better soon and you can get back to this project.
Jan 06, 2020, 01:55 AM
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Thanks for your thoughts on the hand.
I agree the plans do seem to show cracking the main longerons being cracked. I am loath to do such a thing.
I appreciate your info on joining the sides. I have joined many a pair of sides, But I always love to hear some one else's comments on it. I may learn something new or reinforce what I already knew.

I have bent wood including bass with steam before from a tea kettle over the stove. But that is not going to work here.

I keep searching my memory on how I handled the fuse bends when I built the first one while shipboard. I frankly have no ideal how I did it!

Ken
Jan 06, 2020, 02:35 AM
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I'm sure it'll come back to you when you're faced with the same task. Or something new will spring to mind.

We're resilient and resourceful in that way when the chips are down or we wouldn't still be doing this stuff....
Jan 08, 2020, 09:34 PM
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My hand is doing good now, Almost back to the same condition as before.
Wanted to work on the bird yesterday but the day was tied up with Dr apps. for both me and my wife. And since she doesn't drive if she has something, then I got something.

So I got some time on the Pacific Ace today.

Took 2 hours for my heater to get the garage comfortable to work in. Fogy for half the day.

Made the rest of the wing rips. I cut down by 1/16 inch 6 rips for the center section that gets sheeted. Also made the 2 end rips that fit into the wing bows at the ends of the wing.

Then it was time to start joining the fuse sides. Wanted to get the side at least partly joined before starting wing panels in case I needed to use the table saw for something fuse related. The bottom of the fuse center section got a plate I made up from 1/8" lite ply and some 1/32" sheet balsa. Mad a bit over wide and then use the table saw to square off the side that glue to the fuse half's. Used the chop saw to square off the ends. Those tools may be over kill, but man they make some jobs so much easier. Got 'em may as well use them.

So after I had my bottom plate I put the top view on my magnetic board and fitted the sides. Ran into a problem I did not expect. The plans have wide scotch tape over them so glue won't stick. Well turns out my magnet pieces don't stick good to that either. Slide like they were greased. Solved that by just lining up the plans to the reference lines on the board and then the fuse side the same thing. 

So anyway the fuse side joins is started.

The back half's will bend to join at the tail easily. Now bending the front half to the fire wall is going to be the challenging part. I might soak the front half in hot water. Only concern their is the glue joints could fail. Could also just wet the front stringers and the hit them with a hot iron. Well just have to play with it to see what works.

​​​​​​​Ken
Jan 09, 2020, 12:21 AM
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It's always a big moment when the sides are erected into a box structure.


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