Spring Wingin'it Build... Brodak Cardinal

[Randy Cuberly]

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

I will comment on the tank.

That appears to be a "chicken hopper" profile uniflo tank.  They can be made to work very well.  They are typically use for Slow Combat to provide a steady run at relatively high RPM for the entire flight.  The basic principle is that the fuel is actually drawn from a small compartment in the outside of the main tank that is fed only a small orifice inside the tank.  The theory is that the pressure inside the "chicken hopper" portion of the tank remains constant regardless of the main tank pressure.  Since the "Hopper" contains a small amount of fuel the suction required from the engine is less to maintain good fuel flow.  The main reason for this for slow combat is that it typically allows a slightly larger venturi to be used and hence more power.

A small drawback to the use of this style tank can be that it typically requires a richer needle setting on the ground
because it tends to lean out in the air until the hopper stabilizes in pressure.  This typically takes a lap or two after takeoff!  That can complicate the needle setting process!  If you don't mind the fiddle they can be very useful!

Personally for stunt I would simply recommend a standard profile uniflo tank since they are easier to deal with!

I've used both types very successfully! 

Randy Cuberly

[Brett Buck]

Nobody has any good bad thoughts on a tank choice?

   The narrower the better, I would suggest the first rather than the second. Don't have the suck fuel quite as far "uphill" against centrifugal force. This is what causes it to lean out (perhaps beyond control) after takeoff.

       Brett

[Chris Fretz]

I will comment on the tank.

That appears to be a "chicken hopper" profile uniflo tank.  They can be made to work very well.  They are typically use for Slow Combat to provide a steady run at relatively high RPM for the entire flight.  The basic principle is that the fuel is actually drawn from a small compartment in the outside of the main tank that is fed only a small orifice inside the tank.  The theory is that the pressure inside the "chicken hopper" portion of the tank remains constant regardless of the main tank pressure.  Since the "Hopper" contains a small amount of fuel the suction required from the engine is less to maintain good fuel flow.  The main reason for this for slow combat is that it typically allows a slightly larger venturi to be used and hence more power.

A small drawback to the use of this style tank can be that it typically requires a richer needle setting on the ground
because it tends to lean out in the air until the hopper stabilizes in pressure.  This typically takes a lap or two after takeoff!  That can complicate the needle setting process!  If you don't mind the fiddle they can be very useful!

Personally for stunt I would simply recommend a standard profile uniflo tank since they are easier to deal with!

I've used both types very successfully! 

Randy Cuberly

What sizes tank is on yours? It kind of looks small.  Do you have a example of what a standard profile tank looks like?

[Chris Fretz]

   The narrower the better, I would suggest the first rather than the second. Don't have the suck fuel quite as far "uphill" against centrifugal force. This is what causes it to lean out (perhaps beyond control) after takeoff.

       Brett

You lost me there, wouldn't the first be wider than the second narrower one?

[Randy Cuberly]

What sizes tank is on yours? It kind of looks small.

Well, the one on it in that picture was put on it by my brother.  It's actually 5.5 oz.

I originally used a 5.5 oz Profile uniflo tank from RSM, and is what I would recommend.

5.5 ounces is more than adequate for the LA46.  5 ounces is sometimes not!

Randy Cuberly

[Randy Cuberly]

Well, the one on it in that picture was put on it by my brother.  It's actually 5.5 oz.

I originally used a 5.5 oz Profile uniflo tank from RSM, and is what I would recommend.

5.5 ounces is more than adequate for the LA46.  5 ounces is sometimes not!

Randy Cuberly

Check RSM's  and Brodak's websites!

https://www.rsmdistribution.com/main.htm

https://brodak.com/literature/brodak-catalog.html

Randy Cuberly

[Randy Cuberly]

You lost me there, wouldn't the first be wider than the second narrower one?

I believe Brett is considering "wide" and "narrow" as dimensions relative to the engine thrust line to the outside of the flight circle! 

The narrower the tank the less pressure change relative to centrifugal force as the fuel depletes!

Uniflo mitigates this to some extent but it is still a big factor!

Randy Cuberly

[Chris Fretz]

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

I built it with 1.5°  aluminum pads from Tom. But I'm wondering if I'm going to regret that much offset.

[Randy Cuberly]

I built it with 1.5°  aluminum pads from Tom. But I'm wondering if I'm going to regret that much offset.

No it should be just fine!

Randy Cuberly

[Chris Fretz]

Check RSM's  and Brodak's websites!

https://www.rsmdistribution.com/main.htm

https://brodak.com/literature/brodak-catalog.html

Randy Cuberly

All the tanks I can find at either that are uniflow and 5.5oz are 5 1/2 in long or longer and there isn't that much room to use them. That is why yours caught my eye cause it's so stubby. 

[Chris Fretz]

Crudely pieced together but coming along.  Checking fits and controls.

[Randy Cuberly]

All the tanks I can find at either that are uniflow and 5.5oz are 5 1/2 in long or longer and there isn't that much room to use them. That is why yours caught my eye cause it's so stubby.

Well, I measured mine and there is plenty of room for a 5 1/2 in long tank.  However I called Eric Rule at RSM and being the terrific guy that he is he said that all you had to do was call him and order a "5 1/2 oz Snub Nose Uniflo tank" and he would be happy to fill the order!  That tank is approximately 1 1/2 inch high, 2 inches wide  and approximately 4 inches long.  Actually it's precisely what is on mine right now!

Randy Cuberly

[Chris Fretz]

Well, I measured mine and there is plenty of room for a 5 1/2 in long tank.  However I called Eric Rule at RSM and being the terrific guy that he is he said that all you had to do was call him and order a "5 1/2 oz Snub Nose Uniflo tank" and he would be happy to fill the order!  That tank is approximately 1 1/2 inch high, 2 inches wide  and approximately 4 inches long.  Actually it's precisely what is on mine right now!

Randy Cuberly

Huh that's a swell size! I never called Eric but I'm betting I will this holiday weekend. 

Now.... I just barely have 5 1/2 and I filled my gap and made new doublers. Sooooo if your gap is still there how in the world do you have 5 1/2 to play with?? I wanna see a picture with a ruler Mr!

By the way now we are getting somewhere! Thanks Randy!

[Randy Cuberly]

Huh that's a swell size! I never called Eric but I'm betting I will this holiday weekend. 

Now.... I just barely have 5 1/2 and I filled my gap and made new doublers. Sooooo if your gap is still there how in the world do you have 5 1/2 to play with?? I wanna see a picture with a ruler Mr!

By the way now we are getting somewhere! Thanks Randy!

Hmmmm....

Well, how about a little wager my friend?

Wanna' make it worth my while?   Like the ole' Preacher man said All contributions gratefully accepted!

 

[Chris Fretz]

Hmmmm....

Well, how about a little wager my friend?

Wanna' make it worth my while?   Like the ole' Preacher man said All contributions gratefully accepted!

 

A wager that you can jam a 5 1/2 tank on your Cardinal? (On the outboard side mind you)

[Randy Cuberly]

A wager that you can jam a 5 1/2 tank on your Cardinal? (On the outboard side mind you)

I don't have time tonight to take pictures showing you the 5 1/2 in long tank in the space but will tomorrow evening!

The picture below has a 5 oz Snub Snub Nose RSM uniflo tank in place on it.  This tank is 3 1/2 inches long and you can see that there is a lot of clearance between the engine an the wing.  I measured the distance between the back of the exhaust flange on the engine and the root of the wing where it joins the fuselage and it is exactly 5 3/4 inches which leaves an 1/8 inch clearance between both the flange and the wing, with a 5 1/2 oz standard uniflo tank (5 1/2 in long) with the vents modified to exit the top of the tank (common practice and easy to do)!  Actually it could even be made to work by bending the fuel feed line down to clear the engine since the cylinder is another 1/4 inch from the exhaust flange on the LA46 engine!  The better practice however would be to use the 5 1/2 oz snub Nose tank from Eric or reroute the fuel feed line to the top of the tank if you wish to use the long tank!  You would of course also have to use tank mounts on the top and bottom of the tank instead of the ends with the long tank.
There's always another way to skin a cat!  That's what CL Stunt is all about! 

Another thing to consider that I actually hadn't is that depending on where you fly a 5 oz tank might be more than adequate.  It often is not here in Tucson because the common practice here due to the heat and altitude is to use 15 to 20 % nitro and that often demands about 5 1/4 oz of fuel to fly the pattern in the summer months when the temps exceed 100 degrees and the nitro demands can exceed 20% to maintain power!

I will tell you that I have reworked and used many LA46 engines and sold approximately 65 of them to various folks everywhere.  The mods I make are not drastic but slight port angle changes can and do make the engines typically more fuel efficient with a flatter torque curve by simply directing the incoming charge into the cylinder away from the exhaust port.  I taught these changes to a number of people who also modified engines for other folks to the extent that there are likely more than a hundred and fifty or more of these modified engines running around.
They typically use about 4 1/2 to 4 3/4 oz. to fly the pattern.

Here's that nasty  old picture again of my Cardinal Profile and look carefully at the tank and consider that it's 3 1/2 inches long and 1 /1/2 inches high!

Randy Cuberly

[Chris Fretz]

I don't have time tonight to take pictures showing you the 5 1/2 in long tank in the space but will tomorrow evening!

The picture below has a 5 oz Snub Snub Nose RSM uniflo tank in place on it.  This tank is 3 1/2 inches long and you can see that there is a lot of clearance between the engine an the wing.  I measured the distance between the back of the exhaust flange on the engine and the root of the wing where it joins the fuselage and it is exactly 5 3/4 inches which leaves an 1/8 inch clearance between both the flange and the wing, with a 5 1/2 oz standard uniflo tank (5 1/2 in long) with the vents modified to exit the top of the tank (common practice and easy to do)!  Actually it could even be made to work by bending the fuel feed line down to clear the engine since the cylinder is another 1/4 inch from the exhaust flange on the LA46 engine!  The better practice however would be to use the 5 1/2 oz snub Nose tank from Eric or reroute the fuel feed line to the top of the tank if you wish to use the long tank!  You would of course also have to use tank mounts on the top and bottom of the tank instead of the ends with the long tank.
There's always another way to skin a cat!  That's what CL Stunt is all about! 

Another thing to consider that I actually hadn't is that depending on where you fly a 5 oz tank might be more than adequate.  It often is not here in Tucson because the common practice here due to the heat and altitude is to use 15 to 20 % nitro and that often demands about 5 1/4 oz of fuel to fly the pattern in the summer months when the temps exceed 100 degrees and the nitro demands can exceed 20% to maintain power!

I will tell you that I have reworked and used many LA46 engines and sold approximately 65 of them to various folks everywhere.  The mods I make are not drastic but slight port angle changes can and do make the engines typically more fuel efficient with a flatter torque curve by simply directing the incoming charge into the cylinder away from the exhaust port.  I taught these changes to a number of people who also modified engines for other folks to the extent that there are likely more than a hundred and fifty or more of these modified engines running around.
They typically use about 4 1/2 to 4 3/4 oz. to fly the pattern.

Here's that nasty  old picture again of my Cardinal Profile and look carefully at the tank and consider that it's 3 1/2 inches long and 1 /1/2 inches high!

Randy Cuberly

Well in reality I don't really want to see a picture of you jamming the tank in place. I just really want to see how you would mount it and be adjustable. If I remember right my LA46s are using 4.5-4.75oz

[Chris Fretz]

Well, I measured mine and there is plenty of room for a 5 1/2 in long tank.  However I called Eric Rule at RSM and being the terrific guy that he is he said that all you had to do was call him and order a "5 1/2 oz Snub Nose Uniflo tank" and he would be happy to fill the order!  That tank is approximately 1 1/2 inch high, 2 inches wide  and approximately 4 inches long.  Actually it's precisely what is on mine right now!

Randy Cuberly

Hey you actually did call Eric he knew exactly what I wanted too

[Randy Cuberly]

Hey you actually did call Eric he knew exactly what I wanted too

Eric has been my friend for many, many years and he is a really fine Gentleman!  I would never say something regarding him that wasn't true.

Get the 5 or 5 1/2 ounce Snub nose tank.  If what you say about your LA46's is true then by all means get the 5oz tank.

I'm fed up with being doubted by you after trying to help you.  Do what you like!

I said before the 5.5 oz standard tank would have to be mounted with mounts above and below the tank.  I just thought maybe you could figure out how to do that yourself with slots in the mounts to move it up and down!

Randy Cuberly

[Randy Cuberly]

Incidentally, I didn't start doing this stuff yesterday.  In fact I started flying CL in 1952, mostly Combat, started flying stunt in 1957, and have been flying in the Expert class since 1977 (Took some time out for the military in the 60's and early 70's.

You'll find that most people on this Forum that offer advice have been doing it for a while and should command a little respect when they offer it!

A little miffed but will get over it!
Randy Cuberly!

[Chris Fretz]

Incidentally, I didn't start doing this stuff yesterday.  In fact I started flying CL in 1952, mostly Combat, started flying stunt in 1957, and have been flying in the Expert class since 1977 (Took some time out for the military in the 60's and early 70's.

You'll find that most people on this Forum that offer advice have been doing it for a while and should command a little respect when they offer it!

A little miffed but will get over it!
Randy Cuberly!

Eric has been my friend for many, many years and he is a really fine Gentleman!  I would never say something regarding him that wasn't true.

Get the 5 or 5 1/2 ounce Snub nose tank.  If what you say about your LA46's is true then by all means get the 5oz tank.

I'm fed up with being doubted by you after trying to help you.  Do what you like!

I said before the 5.5 oz standard tank would have to be mounted with mounts above and below the tank.  I just thought maybe you could figure out how to do that yourself with slots in the mounts to move it up and down!

Randy Cuberly

I don't really see why you are miffed as you call it. I certainly wounldnt of called Eric to order a tank you suggested if I doubted you. In fact I've done quite a lot of what you suggested. I think you have taken things the wrong way.

[Randy Cuberly]

I don't really see why you are miffed as you call it. I certainly wounldnt of called Eric to order a tank you suggested if I doubted you. In fact I've done quite a lot of what you suggested. I think you have taken things the wrong way.

On the other hand you might consider that you presented them the WRONG WAY!

I'm not used to being treated like a liar and a fool!

Randy Cuberly

[Chris Fretz]

On the other hand you might consider that you presented them the WRONG WAY!

I'm not used to being treated like a liar and a fool!

Randy Cuberly

I don't see where I called you a liar,  you are the one starting bets, and I don't need to help you out looking like a fool cause you are currently doing a good job of that by yourself. Boy you need to lighten up, you come off a bit rude in your replys but I'm not crying about it.

[john e. holliday]

Come on children,  lets get back to having fun.   Yes I know you are older than me. 

Remember you and Walter were some of the individuals I looked up to in my early days with the Flying Eagles.

[Randy Cuberly]

I don't see where I called you a liar,  you are the one starting bets, and I don't need to help you out looking like a fool cause you are currently doing a good job of that by yourself. Boy you need to lighten up, you come off a bit rude in your replys but I'm not crying about it.

You would get farther by showing a little respect to those trying to help you.

However don't expect any help from me again.  All you had to do was a simple apology for questioning my statements about the tank!  You did imply I was lying by your statement " I want to see a picture mister!".

So as a favor to me just dry up and go away...at least from me!

Doc,  I don't think I'm being childish by expecting a little respect from someone I'm trying to help!

You can't "fix" this one by simple statements and certainly not by implying that I'm acting childish.  That's possibly more offensive than the way I was treated by this obviously deliberately offensive Buffoon above!

Best to just leave it alone!

Our friendship goes way back but doesn't allow you to mistreat me by calling me a child!

Randy Cuberly!

[Chris Fretz]

You would get farther by showing a little respect to those trying to help you.

However don't expect any help from me again.  All you had to do was a simple apology for questioning my statements about the tank!  You did imply I was lying by your statement " I want to see a picture mister!".

So as a favor to me just dry up and go away...at least from me!

Doc,  I don't think I'm being childish by expecting a little respect from someone I'm trying to help!

You can't "fix" this one by simple statements and certainly not by implying that I'm acting childish.  That's possibly more offensive than the way I was treated by this obviously deliberately offensive Buffoon above!

Best to just leave it alone!

Our friendship goes way back but doesn't allow you to mistreat me by calling me a child!

Randy Cuberly!

You are a rude arrogant prick. People like you don't deserve this respect that you expect. You can't even handle a guy teasing you about being a child. I guess that's cause you act like one. Learn some sense of humor if you're not too old for that.

I'll do just fine without your arrogance trust me.

[Chris Fretz]

Alrighty then!

Got a lot done this past weekend!

[Chris Fretz]

Wing stab and rudder on.  Fillets sanded some.

[Chris Fretz]

First coat of DC540 on. Got a few spots to fix I see. I also can never remember to get a rattle can snap on easy grip trigger until about 3 seconds into using the DC540. Man those spray nozzles are beyond ridiculous to push down on the DC540 can! But I remembered today to get the snap on grip trigger!  Off to sanding.

[Ken Culbertson]

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.

I used a carbon fiber arrow shaft (from Wallmart $1.50).  Carve a grove in the bottom and epoxy in.  They are lighter than the balsa you removed.  I build up my profiles so they get glued in as the bottom and top stringers before add the walls.  Extend them past the wing TE and you have one stiff fuselage.  By the way, they also make great wing jigs.

Ken

[Chris Fretz]

I used a carbon fiber arrow shaft (from Wallmart $1.50).  Carve a grove in the bottom and epoxy in.  They are lighter than the balsa you removed.  I build up my profiles so they get glued in as the bottom and top stringers before add the walls.  Extend them past the wing TE and you have one stiff fuselage.  By the way, they also make great wing jigs.

Ken

Slick! The things you find out from other people on here never cease to amaze me. Thanks for sharing!

Chris

[RknRusty]

Looks like a pretty tough bird, Chris. I briefly thought about extending my Inboard tripler like yours. It'll give it a nice look. What's the thickness of the rear ply doublers? I'm guessing 1/64th.

Mine is coming along faster now that I'm back on my feet and the wx is warming up. The fuse is ready for detailing with Super Fil, dope, and paper now, and then I can move on to building the wing. Every time I touch it I manage to put a little ding in it, but a tiny drop of water on the fingertip cures most of those minor bumps and dings.

This'll be my first time using Super Fil, I hope I like it. I've been very successful with Microballoons in the past, and the SF looks easier and neater.
Rusty

[Chris Fretz]

Looks like a pretty tough bird, Chris. I briefly thought about extending my Inboard tripler like yours. It'll give it a nice look. What's the thickness of the rear ply doublers? I'm guessing 1/64th.

Mine is coming along faster now that I'm back on my feet and the wx is warming up. The fuse is ready for detailing with Super Fil, dope, and paper now, and then I can move on to building the wing. Every time I touch it I manage to put a little ding in it, but a tiny drop of water on the fingertip cures most of those minor bumps and dings.

This'll be my first time using Super Fil, I hope I like it. I've been very successful with Microballoons in the past, and the SF looks easier and neater.
Rusty

Hi Rusty! Both my Tanagers seem to have vibration issues so I thought I'd try extending the trippler on this one. The doublers are 1/16 just extended on that side. I sanded the trippler on the both Tanagers like the print showed and it makes it so thin at the wing. Don't know if that's why there is vibration problems or not but I'll see if it helps on the Cardinal.

I tried some left over old super fill from last year and it didn't seem to cure all the way. I guess once open it has a shelf life. I just do like I saw on one of Sparkys videos. Tape the area off so less sanding and use alcohol to smooth it after it cures a bit. It seems easy enough to sand, I bet you'll like it, make sure you mix it throughly.

I dink the crap out of the fuse too. I was sanding the fuse and the cat bit the stab, had to fill the teeth marks in. The cat loves the leadouts too.

The weather still sucks here!

Chris

[Chris Fretz]

Almost done, few pictures to update.

[Chris Fretz]

Another...

[Chris Fretz]

Put some clear on today.

[RknRusty]

I wish my Cardinal build was that fast. But every time I go out to the shop, the building fairies have done nothing!

[Chris Fretz]

I wish my Cardinal build was that fast. But every time I go out to the shop, the building fairies have done nothing!

Maybe try some milk and cookies Rusty!?

[RknRusty]

Milk and cookies, yeah good idea.
Maybe a bong and some chips & dip for artistic flair... but not until they finish the control system Lol.
Thanks, Chris.