Spring Wingin'it Build... Brodak Cardinal

[Chris Fretz]

Ok so I doubt it will really be a rush build since I can't make up my mind on what to do... esp with trying to strengthen the fuse up after the wing. So definitely wingin'it here!

I got the wing started. Pretty flimsy at point. Pain in the butt shimming the taper on this wing.

I did epoxy the motor mounts in today. I'm going to try really hard to not over due it on the epoxy like I have on previous builds.

It will have a LA46 in it.  How well does the LA46 balance on this airplane?

[Chris Fretz]

Sure is a big gap behind the engine. Not sure what the plan was for that. Lots of waisted real estate for mounting a tank. I plan on cutting new 1/16 doublers to shorten the big gap and filling it in with 1/2 balsa.

[Chris Fretz]

Waiting on the epoxy to cure.

[Chris Fretz]

 I'm going to go with the usual Tom Morris controls like i have in the last like 5 airplanes or so. I'm currently on hold with the wing waiting on the controls to arrive. When I get them I can then figure some way to stuff the suspended bellcrank in.

[Chris Fretz]

 So anyone got any good pictures on how to stiffen up the fuse?  Poor Rusty is getting the 2nd and 3rd degree on how to stiffen his. But I know he will figure something out.

I have a carbon fiber bar like Rusty, I have Brodak carbon veil, and earlier in the week I ordered Dave Brown carbon fiber strips. Soooo can anyone devise a plan with those items?

I like the simplicity and looks of this if it will work. Sorry for stealing the picture to whom it may concern. However it doesn't seem like the carbon fiber strips could do much strengthening when they are so flimsy in the direction you want it to strengthen. Unless coupled with the epoxy makes a huge difference. Got me no experience with this, my Tanagers are as flimsy as paper after the wing.

[Randy Cuberly]

Sure is a big gap behind the engine. Not sure what the plan was for that. Lots of waisted real estate for mounting a tank. I plan on cutting new 1/16 doublers to shorten the big gap and filling it in with 1/2 balsa.

Well, of course there are a number of engines around that might be used on a "Cardinal" with much longer shaft lengths than the one pictured!  Obviously that would require setting the engine farther to the rear.  Probably easier to "fill in" than "cut out".     

Randy Cuberly

[Chris Fretz]

Well, of course there are a number of engines around that might be used on a "Cardinal" with much longer shaft lengths than the one pictured!  Obviously that would require setting the engine farther to the rear.  Probably easier to "fill in" than "cut out".     

Randy Cuberly

Must of been designed for a massive engine then...

[Brian Gardner]

Perhaps the design thought was that if you were going to run a heavy engine you couuld mount it further back and then trim/move the nosring back to match.......

[Chris Fretz]

Perhaps the design thought was that if you were going to run a heavy engine you couuld mount it further back and then trim/move the nosring back to match.......

Now that's a good thought there!

[Chris Fretz]

Well, of course there are a number of engines around that might be used on a "Cardinal" with much longer shaft lengths than the one pictured!  Obviously that would require setting the engine farther to the rear.  Probably easier to "fill in" than "cut out".     

Randy Cuberly

Randy I found the engine this airplane was designed for...

[Randy Cuberly]

Randy I found the engine this airplane was designed for...

No, that wouldn't work you'd have to cut the engine slot almost 1/4 inch deeper!

Actually An LA 46 fits just fine as witnessed by the one on mine!  Probably the best possible choice also! 

Randy Cuberly

[Chris Fretz]

No, that wouldn't work you'd have to cut the engine slot almost 1/4 inch deeper!

Actually An LA 46 fits just fine as witnessed by the one on mine!  Probably the best possible choice also! 

Randy Cuberly

I don't know about you but I found that funny!
Did you fill the gap on yours? Share a picture of it!

[Randy Cuberly]

I don't know about you but I found that funny!
Did you fill the gap on yours? Share a picture of it!

Nope!  The Gap's still there!  It's been around a long time!  Originally built when the kit was first released.  When first built I considered using it as a test bed for different engine work on different engines.  It flew so well and trimmed very nicely so I decided to use it in Profile competition.  There was no engine size limitation on Profile her in AZ.
I won several contests here and always placed well! 

I also did very little to stiffen the fuselage and it just didn't seem to matter.  It's pretty stiff as it is!  About the only thing I mad any effort to stiffen was the flaps and they got the typical two layers of .5 ounce glass and epoxy (very tin and scraped almost dry).  That's probably the most important thing to make stiff. 

After I tired of it (didn't take long, maybe 1 season), I gave it to my brother Rick who was a very serious Intermediate flier and He used it for a two seasons to move to the upper ranks of Advanced!  He then built a "Time Machine" and in less than a season moved to Expert!

He gave the "Cardinal" back to me and I used it to train a couple of Newbies and then gave it to one of them.  He flew it a few times and learned most of the pattern with it, then decided He didn't want to continue and gave it back to me.

Ever have something that just kept coming back to you!  Can't explain it.

It's back now and everything works except the tank (full of holes).  I'm going to replace the tank get it flying and find it a new home!

Anyone coming to VSC that has a Newbie on the line can have it for the asking!

Randy Cuberly

[Steve Helmick]

It appears that Brian Massey has a customer for a "free Cardinal", if you are to believe his "Maiden Flight" thread. I would stipulate that it could NOT be converted to electron power, however.  Steve

[Randy Cuberly]

It appears that Brian Massey has a customer for a "free Cardinal", if you are to believe his "Maiden Flight" thread. I would stipulate that it could NOT be converted to electron power, however.  Steve

Sounds like a good idea if He's coming to VSC!  Or if someone who knows him is coming and wants to take it to him!

Randy Cuberly

[Carl Cisneros]

Chris;

On my new profile ship, I am going to be using 1/32" ply from nose to tail along with the 1/8" ply doublers up front as always.

Carl

[Steve Helmick]

The 1/64" ply on both sides would be very adequate. Years ago, it was described as "Poor Man's Carbon Fiber", but now it isn't as cheap as .5 oz CF mat. Two layers of .5 oz CF mat applied with finishing epoxy would be my choice.    Steve

[Chris Fretz]

Nope!  The Gap's still there!  It's been around a long time!  Originally built when the kit was first released.  When first built I considered using it as a test bed for different engine work on different engines.  It flew so well and trimmed very nicely so I decided to use it in Profile competition.  There was no engine size limitation on Profile her in AZ.
I won several contests here and always placed well! 

I also did very little to stiffen the fuselage and it just didn't seem to matter.  It's pretty stiff as it is!  About the only thing I mad any effort to stiffen was the flaps and they got the typical two layers of .5 ounce glass and epoxy (very tin and scraped almost dry).  That's probably the most important thing to make stiff. 

After I tired of it (didn't take long, maybe 1 season), I gave it to my brother Rick who was a very serious Intermediate flier and He used it for a two seasons to move to the upper ranks of Advanced!  He then built a "Time Machine" and in less than a season moved to Expert!

He gave the "Cardinal" back to me and I used it to train a couple of Newbies and then gave it to one of them.  He flew it a few times and learned most of the pattern with it, then decided He didn't want to continue and gave it back to me.

Ever have something that just kept coming back to you!  Can't explain it.

It's back now and everything works except the tank (full of holes).  I'm going to replace the tank get it flying and find it a new home!

Anyone coming to VSC that has a Newbie on the line can have it for the asking!

Randy Cuberly

Ohh yes I've seen that pictures in my searches!  So explain this stiffening of the flaps to me... are you doing this so they don't flex wile doing stunts?

Chris

[Chris Fretz]

Chris;

On my new profile ship, I am going to be using 1/32" ply from nose to tail along with the 1/8" ply doublers up front as always.

Carl

How much weight will that add? Are you using epoxy for that?

Chris

The 1/64" ply on both sides would be very adequate. Years ago, it was described as "Poor Man's Carbon Fiber", but now it isn't as cheap as .5 oz CF mat. Two layers of .5 oz CF mat applied with finishing epoxy would be my choice.    Steve

What is finishing epoxy?

[Chris Fretz]

I've heard some people say the flap are too wide on this airplane. Whats everyone's thoughts on this?

[Fredvon4]

In my opinion stiffening a profile fuse originally from solid 1/2 balsa is easy

 I remove weight from aft of TE with cut out sections then fill with no weight white foam inserts

I do not care to carve the top or bottom of the fuse rounded or tapered... So I epoxy on a 1/64th Cap strip top and bottom...this greatly increases stiffness
I lay heavy 2oz CF veil or .75 FG on the sides with epoxy finish resin...

I did one with 1/64ths  on both after cut outs and running the fuse in the planer to reduce width a bit

In each case I ended up with much stiffer for very close to original weight of the provided Balsa Fuse

NOTE to further reduce aero dynamic twisting from Elevator....make sure the control surface hinge line is dead on 90 degrees to the fuselage

Of all the effort I think I can say the top and bottom 1/64 ply caps do most/all the stiffening work...both torsional and side to side flex

[Dave Harmon]

I've heard some people say the flap are too wide on this airplane. Whats everyone's thoughts on this?

The info I have for the Cardinal flaps is....cut down the flaps to 2.5" at the root and 1.5" at the tip.

[Steve Helmick]

What is finishing epoxy?

Chris, you should find this stuff at your LHS. If not, well, order online or find another LHS! It's really easy to sand, which is a major deal. Truthfully, I'd probably cover over those two layers of .5 oz CF/epoxy with a layer of light silkspan/clear dope, to avoid the pinholes and stuff that CF is famous for.  Steve

http://www.supergluecorp.com/?q=zap/z-poxy-line/zap-z-poxy-finishing-resin

[Chris Fretz]

Chris, you should find this stuff at your LHS. If not, well, order online or find another LHS! It's really easy to sand, which is a major deal. Truthfully, I'd probably cover over those two layers of .5 oz CF/epoxy with a layer of light silkspan/clear dope, to avoid the pinholes and stuff that CF is famous for.  Steve

http://www.supergluecorp.com/?q=zap/z-poxy-line/zap-z-poxy-finishing-resin

Ahhhhhhh so that's what Z-poxy is all about. I keep seeing people talk about but I didn't know it was finishing epoxy.  Do you thin it or does it spread pretty good?

[Steve Helmick]

The finishing resin is thin and already flows out nicely. Not saying that thinning it might not be better yet, but I know you don't want to brush the snot out of CF mat, because it will pull the fibers around and get messy. Some guys report having used this same epoxy for sheeting foam wings and laminating plywood doublers, with good results.  Steve 

[Chris Fretz]

The info I have for the Cardinal flaps is....cut down the flaps to 2.5" at the root and 1.5" at the tip.

Thanks for sharing!

[Chris Fretz]

The finishing resin is thin and already flows out nicely. Not saying that thinning it might not be better yet, but I know you don't want to brush the snot out of CF mat, because it will pull the fibers around and get messy. Some guys report having used this same epoxy for sheeting foam wings and laminating plywood doublers, with good results.  Steve

How would you apply Z-poxy to the carbon fiber?

[Chris Fretz]

In my opinion stiffening a profile fuse originally from solid 1/2 balsa is easy

 I remove weight from aft of TE with cut out sections then fill with no weight white foam inserts

I do not care to carve the top or bottom of the fuse rounded or tapered... So I epoxy on a 1/64th Cap strip top and bottom...this greatly increases stiffness
I lay heavy 2oz CF veil or .75 FG on the sides with epoxy finish resin...

I did one with 1/64ths  on both after cut outs and running the fuse in the planer to reduce width a bit

In each case I ended up with much stiffer for very close to original weight of the provided Balsa Fuse

NOTE to further reduce aero dynamic twisting from Elevator....make sure the control surface hinge line is dead on 90 degrees to the fuselage

Of all the effort I think I can say the top and bottom 1/64 ply caps do most/all the stiffening work...both torsional and side to side flex

Sounds like plenty of ways to stiffen them up!  Pick your poison I suppose. Thanks for sharing!

[Randy Cuberly]

Ohh yes I've seen that pictures in my searches!  So explain this stiffening of the flaps to me... are you doing this so they don't flex wile doing stunts?

Chris

Absolutely!  The flaps are essentially a long plank with a torsion arm at one end.  The dynamic air loading on the surface of the flap can cause the flap the bend in torsion relative to that load!  Wood is not a very consistent material structurally so if one flap flexes in torsion more than the other that's a serious trim problem, or if the end of the flap at the tip flexes more than the root, that's a trim problem!  Some of that is countered by the fact that most flaps taper from the center of the wing to the tip and therefore the flight (air) loading is less at the tip due to smaller area.  However the flap is narrower also and it may not compensate enough.  Also the area flow at the tips is more turbulent and may tend to cause "flutter" on a wimpy flap there! (Another reason you may see two hinges near the tip on large stunter's wings.) 

The amount of weight added with my particular method of two layers of .5 ounce glass cloth is highly dependent on the amount of epoxy resin applied and the reason I said scraped very thin!  On the flaps I did recently on my Colossus this technique added approximately .25 oz per flap or about .5 oz for both.  It should be noted that the flaps are not exactly the same size.  At any rate 1/2 oz is an excellent trade off for stiff flaps on any stunter.

The Colossus is a large airplane at approximately 60 inch span and has large flaps by modern standards!
I'm using about a 2/3 to 1 ratio between the flap and elevator travel to reduce the control loads and feedback!
They don't flex however, at least not that I can tell!

I cannot speak to the use of Carbon Mat because I do not use the stuff but a lot of folks I respect do so I would assume it works about equally well!

Randy Cuberly

[Chris Fretz]

Absolutely!  The flaps are essentially a long plank with a torsion arm at one end.  The dynamic air loading on the surface of the flap can cause the flap the bend in torsion relative to that load!  Wood is not a very consistent material structurally so if one flap flexes in torsion more than the other that's a serious trim problem, or if the end of the flap at the tip flexes more than the root, that's a trim problem!  Some of that is countered by the fact that most flaps taper from the center of the wing to the tip and therefore the flight (air) loading is less at the tip due to smaller area.  However the flap is narrower also and it may not compensate enough.  Also the area flow at the tips is more turbulent and may tend to cause "flutter" on a wimpy flap there! (Another reason you may see two hinges near the tip on large stunter's wings.) 

The amount of weight added with my particular method of two layers of .5 ounce glass cloth is highly dependent on the amount of epoxy resin applied and the reason I said scraped very thin!  On the flaps I did recently on my Colossus this technique added approximately .25 oz per flap or about .5 oz for both.  It should be noted that the flaps are not exactly the same size.  At any rate 1/2 oz is an excellent trade off for stiff flaps on any stunter.

The Colossus is a large airplane at approximately 60 inch span and has large flaps by modern standards!
I'm using about a 2/3 to 1 ratio between the flap and elevator travel to reduce the control loads and feedback!
They don't flex however, at least not that I can tell!

I cannot speak to the use of Carbon Mat because I do not use the stuff but a lot of folks I respect do so I would assume it works about equally well!

Randy Cuberly

Very nice looking airplane. Do you use Z-poxy to apply the glass cloth or say a 30min Bob Smith epoxy? Are you applying the cloth to both sides at one time?  Are you applying the 2 layers at one time as well? Do you do it to elevators that are not build up like the Cardinal?

Chris

[Randy Cuberly]

Very nice looking airplane. Do you use Z-poxy to apply the glass cloth or say a 30min Bob Smith epoxy? Are you applying the cloth to both sides at one time?  Are you applying the 2 layers at one time as well? Do you do it to elevators that are not build up like the Cardinal?

Chris

Thanks for the compliment!  It does have a few issues with the finish and hasn't been rubbed out yet, but seems to be working well for a Classic legal airplane with a relatively small tail volume!  It does require some concentration!
The RO Jett 61 running on a header muffler has turned out to be a blessing!  It requires no fussing and simply growls along no matter what!

I use West Systems 105 Epoxy Resin with West Systems 206 (slow hardner) for laminating and finishing purposes
like glass cloth.  It's easy to work with and goes on nice and smooth.  I do the layers individually with about 24 hours between layers with very light sanding between the layers.  Very Stiff!  Great stuff, from "Aircraft Spruce"!

Randy Cuberly

[Chris Fretz]

Don't look like the original landing gear is going to be long enough.  If I would use the 12.25x3.75 prop.

[Chris Fretz]

Anyone have any thoughts on using this style uniflow 5oz tank?

[Chris Fretz]

Or maybe this uniflow tank?

[Chris Fretz]

Nobody has any good bad thoughts on a tank choice?

[Skip Chernoff]

Chris you're doing a nice job on the Cardinal. Regarding the tank,just make sure it's big enough to get you through the pattern with some reserve .
At one of the contests Rich Martinez's plane had just enough fuel to do the pattern. He started the engine and there was a big shift in the wind. The judges moved their chairs to the other side of the circle. He ran out of fuel 1/2 way thru the cloverleaf.....S...t happens!

[Chris Fretz]

Chris you're doing a nice job on the Cardinal. Regarding the tank,just make sure it's big enough to get you through the pattern with some reserve .
At one of the contests Rich Martinez's plane had just enough fuel to do the pattern. He started the engine and there was a big shift in the wind. The judges moved their chairs to the other side of the circle. He ran out of fuel 1/2 way thru the cloverleaf.....S...t happens!

I was wondering about that head pressure stuff, I don't really know if the shape of the tank makes much of a difference when uniflow or not.

I got a couple sweet deals at Lebanon. I didn't see you there. Although I was running around like a kid in a candy store!  I got a inbuilt ARF Nobler for $45 wow weeee!

[Skip Chernoff]

I was there ,we must have passed like ships in the night. The tank you have on there now should work fine,just put it on muffler pressure and see how it goes.After filling close the top vent,run pressure line from muffler to overflow vent.....Try it.

[Chris Fretz]

These wing tip blocks weigh a ton even sanded .8oz  anyone lighten them up somehow?

[George Grossardt]

These wing tip blocks weigh a ton even sanded .8oz  anyone lighten them up somehow?

They don’t look like they are hollowed out.  If they are not, start cutting and sanding wood out.

[Chris Fretz]

They don’t look like they are hollowed out.  If they are not, start cutting and sanding wood out.

I just did a Google search and saw that's what people do,  I better get to it!  Thanks!

[Chris Fretz]

 Ok now that looks better. Blew through a coupe spots but patched up.

[Steve Helmick]

Make certain  that the leadout guide (and tipweight box) are solidly fastened into the wingtip. Don't ask. You can't glue a leadout guide to a soft 1/16" rib and expect it to stay put for long. At least, not if you actually adjust it, which you should.  Steve

[RknRusty]

Looks like you're getting it done, Chris. Good work and learning a lot as you go. The only thing I can add to your tank questions is, if you want to run pressure, make sure the required fuel load for a pattern leaves some air inside too. Since the fuel doesn't compress and the air does, then that'll help keep your fuel pressure more constant as the level drops.

I learned that on our show last week and it would explain why my Twister's fp.40 would take off and fly right with a lipping full tank, and then gradually speed up as the fuel level dropped while the increasing "sqishy" air volume couldn't push the fuel out as fast. And then flying with the open uniflow vent solved that. I didn't know why at the time. I prefer the closed loop to keep dry grass seeds and bits out of the system. And I need a bigger tank.

Gawd, I hope that makes sense to someone else here so I don't get hammered for thinking such a thing.
Rusty

[Chris Fretz]

Looks like you're getting it done, Chris. Good work and learning a lot as you go. The only thing I can add to your tank questions is, if you want to run pressure, make sure the required fuel load for a pattern leaves some air inside too. Since the fuel doesn't compress and the air does, then that'll help keep your fuel pressure more constant as the level drops.

I learned that on our show last week and it would explain why my Twister's fp.40 would take off and fly right with a lipping full tank, and then gradually speed up as the fuel level dropped while the increasing "sqishy" air volume couldn't push the fuel out as fast. And then flying with the open uniflow vent solved that. I didn't know why at the time. I prefer the closed loop to keep dry grass seeds and bits out of the system. And I need a bigger tank.

Gawd, I hope that makes sense to someone else here so I don't get hammered for thinking such a thing.
Rusty

I hate tank set ups... can you tell? 

I took your advise from a previous thread and put a hardwood block for the landing gear since a lot of mine crush there after time. How is your Cardinal coming?
Chris

[RknRusty]

Actually, there is a hardwood block for that in the kit. I put balsa there since I'm making wing-mounted gear.
And yeah, power plants... tanks and engines, can be a whole 'nother hobby by themselves.
Rusty

[Chris Fretz]

Actually, there is a hardwood block for that in the kit. I put balsa there since I'm making wing-mounted gear.
And yeah, power plants... tanks and engines, can be a whole 'nother hobby by themselves.
Rusty

Hi Rusty!  I put that block in but I added another block where the landing gear clamps are so it wouldn't crush when tightening then down.

[Chris Fretz]

 My progress so far.  Made lots of balsa dust sanding.  Trippler on,  put Dave Brown carbon fiber strips on. Used Z-poxy to apply one .5 carbon fiber cloth. Maybe I should of  scrapped as much of the Z-poxy off of the cloth as possible I don't know. I gained 1oz with the carbon fiber strips and one layer of .5 carbon fiber cloth.  Definitely made it stronger from twisting but still wags its tail. All I have left is .2oz carbon fiber cloth if I put another layer on or not.  Made a big mistake ordering a control system, I didn't mention it was a profile cardinal and I got controls for a full fuse cardinal. Little set back but got the right horns so I can move on now.  Live and learn I guess.

[Chris Fretz]

Thanks for the compliment!  It does have a few issues with the finish and hasn't been rubbed out yet, but seems to be working well for a Classic legal airplane with a relatively small tail volume!  It does require some concentration!
The RO Jett 61 running on a header muffler has turned out to be a blessing!  It requires no fussing and simply growls along no matter what!

I use West Systems 105 Epoxy Resin with West Systems 206 (slow hardner) for laminating and finishing purposes
like glass cloth.  It's easy to work with and goes on nice and smooth.  I do the layers individually with about 24 hours between layers with very light sanding between the layers.  Very Stiff!  Great stuff, from "Aircraft Spruce"!

Randy Cuberly

Did you put any rudder or engine offset on yours?

[Randy Cuberly]

Did you put any rudder or engine offset on yours?

No rudder offset.  It usually just creates problems unless it's adjustable and even then it usually winds up dead straight.

I did use about 1 degree of engine offset.  Tom Morris sells aluminum tapered rails for offset in (I think) 1 degree and 2 degree increments.  I used the 1 degree set.  However I think standard #4 washers under the front of the engine mounts will work about the same!

I always use 3/32 aluminum plates under the engine mounts on all airplanes to resist compression and fuel softening of the engine mounts anyway and highly recommend doing that.  The Tom Morris units do both the offset and the protection on profiles!

Randy Cuberly