Brodak Cardinal

I would like to know what you guys are flying for lap times on your Cardinals and what your using for power.I am on 60ft eye to eye lines.I am set on the plans CG .I have my handle spacing opened up to max and the corners seem dead.I have been moving the lead outs forward.It flys super smooth.It stays out nice ect even at a slow 5.3 sec lap.Any help would be great.Thanks Dennis

What's the power? Lines are probably two to four feet short, depending, and the lap time is ok, maybe on the slow side, depending on altitude, temp, etc.

Same inside and outside corners? Are the pushrods maybe flexing on insides? Most guys use CF pushrods from flap to elev., but at least a guide is needed. If loops one direction are easier than the other, adjust the elevator pushrod length or the handle bias. Bear in mind that most kit plans show a SAFE CG, and you are entitled to move the CG to suit you. A stunter should not respond like a combat model, so don't make it do that. It should go exactly where you want it, no more, but no less. Most of us are somewhat hampered by our combat flying of years ago. I am personally hampered by lousy glasses. Bifocals are dangerous to fly with, confusing you about where the ground really is. Try running with Bifocals! My prescription sunglasses are my alternate, but I don't see well with them at all, and they're my newest 'script. Hmmmm. Gotta fix that.

First look at handle bias...major fubar of my own doing <blush>, discovered by Paul Walker before he flew my ex-Dirt Mutant Magnum at our Trimming Clinic in July. Heck, I can't even see the elevator. But it made a lot of difference, anyway.

The pushrod adjustment made a lot of difference on Jerry Day's Cardinal, just one turn on the clevis. It changed from not feeling safe to loop into fun (for me) to do inside and outside triangles. Your description is very much like Jerry's airplane on the first few flights. Are the wings level? Can you look straight down the flap hingeline when flying level? A flap tweek, pushrod length ajustment and control ratio revisions fixed his. Thanks, PW!

I just looked at the Brodak Cardinal plans, to confirm what Jerry and Mike Haverly said, that the pushrod from the bellcrank is not shown going to the top hole on the flap horn, but the elevator pushrod does. This was an issue that PW didn't approve of on at least Jerry's Cardinal at our recent Trimming Clinic. The flaps are a large percentage of the control load (driven entirely by line tension), so the more leverage the better. It is very unusual for the controls to be rigged that way. Perhaps John Miller will comment, as the CAD artist on the project.

Be patient and careful with the model until you get it working right...don't push the envelope, and do one adjustment at a time. The Brodak Cardinal is a very good flying model when straight and trimmed properly. How about posting a picture? If you can email me one, I can post it, if that's an issue. Steve

>I just looked at the Brodak Cardinal plans, to confirm what
>Jerry and Mike Haverly said, that the pushrod from the
>bellcrank is not shown going to the top hole on the flap
>horn, but the elevator pushrod does. This was an issue that
>PW didn't approve of on at least Jerry's Cardinal at our
>recent Trimming Clinic. The flaps are a large percentage of
>the control load (driven entirely by line tension), so the
>more leverage the better. It is very unusual for the
>controls to be rigged that way. Perhaps John Miller will
>comment, as the CAD artist on the project.

Yep, that's the way I drew them. Here's the reasoning behind the unusual configuration.

When laying out the control system originally, I found that there was a lot of error, using the RC type horns that were to be used with the kit Cardinal. I would have liked to include a drawing showing the corrected flap horn, butthat wasn't an option with this kit. So I started moving the control attachment points and checking out whether or not I could come up with a more linear control system using the stock units.

It happens that connecting the bellcrank to flap as shown, offered amlmost complete linearity to the flaps, as well as more flap deflection. The deflection when using the top hole was only about 20 degrees with a fair amount of bias. couple this flap error to the elevator link, and it was not good. With the controls as shown, there is very little in the way of bias. I don't remember exactly what the throws worked out to, but I believe there was slightly more elevator than flap.

As for leverage, the lower attachment of the flap pushrod should offer as much or more leverage to the system. Long arm to a shorter arm equals more leverage.

With the Cardinal I'm flying, set up as shown on the plans, I find that I'm flying with the handle adjusted to almost it's full throw. The turns were quick enough until I layed off flying it in favor of another plane with a further aft CG. Now, after flying it last weekend, I intend to add some tail weight. I can also add more flap, or more elevator, if needed. I fly mine on 66 foot center to center .018 lines, with an LA .46 10.5-4 pitch prop and a macs muffler. Lap times are about 5.3-5.5.

As noted in another post, the CG location was calculated as 25% MAC. I believe that for this design, that is a conservative figure. You might try moving the CG aft in small increments. You should find a location that offers a compromise between agility and stability to suit your style.

Change the flap attachment point if you want, but you will lose some symetry in the control system.

Hope this answers the questions concerning the slightly unusual control attachments. If some one would like the amount of throws possible, as well as the assymetry, I can work that out and post it here.

I'm wondering why everything is spinning around?

>
>As for leverage, the lower attachment of the flap pushrod
>should offer as much or more leverage to the system.

Long
>arm to a shorter arm equals more leverage.

To clarify this---Long arm to short arm yields more throw but at increased control load. THe LEVERAGE or force available is actually less. This is why Isaac Newton asked for such a long 2x4 when he needed to move the earth.

The Cardinal we've been working with here seems to like going a bit faster than you are flying--Johns numbers seem right. at 5.3 on 60's the plane may be a bit less than perky, depending on what it weighs.

FWIW

How much up and down movement do you get with your controls? If the flaps are at 20 degrees, are the elevators at 20, also (more? less?). If you give up and lock the controls, can you bend the flap or elevator back to neutral by hand? Check the same way with down. I had one plane (built many long years ago) where the pushrod from the belcrank to the flap horn was flexing. It doesn't happen often, but it can if things are not set up properly.

And (I will save Ted the trouble. He will love me for this) how much space is there in your hinge line? If you have gaps, you will benefit from taping the hingeline. (Even if you don't have major gaps, you may benefit--some will say "will"). And check the balance point again. Sometimes this is deceiving. If your plane is ultra stable, wrap a little solder around the tail strut. Just do a little at a time to see what affect this has.

Always make changes slowly and be careful while flying. Don't do anything stupid.

And I would agree, that it looks like you are a little slow for the line length. If you have good power, you can lengthen the lines and maintain lap speeds (increase flight speeds).

Lots of things to check.

Hi Dennis. I am flying mine on 63 foot lines with an OS .46 LA. Just love that engine. I have flown mine with a ST .46 and an OS .40 FP (P40 events). With the LA 46, I am getting 5.3 lap times with lots of line tension, overheads and all maneuvers. My trim is not right on the money so some of my maneuvers leave something to be desired, or is it just me? Any way the plane is a great flyer and mine is a tad tail heavy and turns very smoothly and if I really put it to it does 90 degree corners right now. Its weight is 43 oz.

I think that I have to start creeping the CG aft.The plane is so stable.It is the most honest flying plane I have ever had .I just need to liven it up a bit.I sent Steve some pictures and he said he was going to post them.Leonard it has a carbon pushrod ect so no flex.It does turn just slow.Inside and outsides are about equal.I need to play with props and get a bit more speed.It does have about 5 deg more elevator travel than flap.Dennis

Hi Ty,
Just wondering how you'd compare your LA46 with the Super Tigre 46? I've been using a LA46 for three years now on a Cardinal, it's 'DA BOMB'(good) on 64'X.018 w/ 11x5 Rev up, 2-4-2-4-2

Dennis: bet the farm...'tail weight' also if you could move the bell crank pushrod down, closer to the flap?

Mark, so far it appears to put out more power, is as easy to start and I use an 11X5 prop with 10% nitro 22% oil (50/50). But it doesn't sound like the ST (grin).

Hi Ty,

That pretty much the set up I'm using, Sig 10% nitro with caster add to 22% total, two head gaskets, .285 venturi, ST needle, 11x5 Zinger,(had been using 11x6 Top Flite, launching at 80-8500) now 9000-9200 seems better line tension & Big Art muffler.