Astron Falcon Pylon/Build

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Planet Andy

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Okay so all you guys who were involved in my mach 10 vs. falcon pileup...I've got a specific question about the Falcon for those of you who have built it and or may have one for reference. I've been unable to find the answer within the (courtesy jim Z) plans and nobody seems to have done an EMRR review. What is the thickness of the pylon piece and if possible the dimensions? Seems like it came pre cut minus the feathering with the kit so there's no template for it. Looks like a lazy rectangle shape. That's all that I'm missing at this point.
I'll try to keep you all comprehensive on the build using this thread.

Thanks,
Andy
 

BobH48

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Andy,

The pylon for this kit was the fins from the Astron Scout. Look at the plans on JimZ's site for kit # K-1. It will have the demensions on it.
 

Planet Andy

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Originally posted by BobH48

The pylon for this kit was the fins from the Astron Scout. Look at the plans on JimZ's site for kit # K-1. It will have the demensions on it.

Bob,

In the time I've gone over and goofed off at the water cooler after goofing off on TRF you've got me covered. Thanks so much.

A T
 

powderburner

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If the pylon was made from the same balsa as the fins from an Astron Scout, then the wood grain would be running in the wrong direction. It should not be going fore-n-aft, but should be parallel to the pylon leading edge.

It has been many moons since I built a Falcon, but I seem to remember the pylon being the same thickness as the main body. You should be able to verify that visually if you can find any good front-end photos of someone's finished falcon?
 

Planet Andy

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alrighty... a little googleizing of "estes BFS60S" brought me to


https://www.ninfinger.org/~sven/rockets/body_tubes.html


they've got a chart (you guys probably already know this) that gives the estes part numbers of various balsa sheets and their thicknesses. Looks like the part in question BFS60S=3/16" and if I'm to believe the original drawings the grain is pictured perpendicular to the body tube and main body pieces. Now with the fin pattern, thickness and suspect grain direction I should be all set. Thanks Bob and Powderburner.

Andy
 

BobH48

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Originally posted by powderburner
If the pylon was made from the same balsa as the fins from an Astron Scout, then the wood grain would be running in the wrong direction. It should not be going fore-n-aft, but should be parallel to the pylon leading edge.

It has been many moons since I built a Falcon, but I seem to remember the pylon being the same thickness as the main body. You should be able to verify that visually if you can find any good front-end photos of someone's finished falcon?
I'm positive about the pylon.

Estes used to sell the BFS60S fins in a three pack and after I built my first falcon I bought 2 sets of the fins. I have since used one set (three fins) on replacment Falcons and I still have one set left. The grain did run parallel to the body tube but was thick enough and short enough not to cause a problem.
 

GuyNoir

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Originally posted by Andy Turits
Okay so all you guys who were involved in my mach 10 vs. falcon pileup...I've got a specific question about the Falcon for those of you who have built it and or may have one for reference.
I posted some Astron Falcon tips on RMR. I'm summarizing them and reposting them here for consideration.

(a) You need some difference between the angles of attack between the stab and the wing to get this bird to glide.

I originally took to putting a small wedge under the trailing edge of the stab to force this angle into place. If this wasn't done JUST precisely right, the bird would glide great, but loop into the ground under power.

The secret to getting good Estes Falcon performance is to put the incidence in the WING. (I stole this idea shamelessly from Kevin Stumpe, husband of NAR HQ manager Marie Stumpe.) He suggested 2-3 degrees of incidence in the wing to me during one of my NAR HQ visits. Putting the incidence there means it's close to the boost CG, and will thus have less of a moment arm to work through during boost.

As soon as the engine spits, then the CG shifts, and the moment arm gets a lot longer, and more effective. Instant pull-out from a dive.

How to get that angle in there, you ask?

You could try eyeballing it, but I prefer to cut a couple of small balsa triangles to the 2 degree angle, glue them first to the fuselage, then glue the wings in place using the triangles as a guide.

You just need a rectangle of 1/16" balsa as long as the root edge of the wing.

Now split the rectangle into two triangles, by measuring a 2-3 degree angle and cutting it on that diagonal.

Build the Falcon fuselague stock.

Now take the triangle, and glue the straight edge of one of your triangles such that the 2-3 deg. angle is located at the wing glue location.

Glue wings in place, and voila!

When I used this trick on my Canon City NARAM Falcon, it worked perfectly for 6th place in teams. Not bad for a 30+ year old design whacked together in less than 2 days.

(b) Introduce some roll on boost.

I do this by canting the pod a bit to one side.

DON'T overdo it.

To get the alignment right, I center a 1/8" dowel in an expended engine casing, insert that into the body tube, and then align the tube on the pylon such that the thrust line is about 1" to the right of center at the trailing edge of the stab. If you more than 1", the model expends too much energy spinning and won't get any altitude. In retrospect, I think you can get by with less, say maybe 1/2".
 

powderburner

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Andy,
BobH48 was correct when he posted that the pylon grain runs fore-and-aft. It is also NOT the same thickness as the body, as I posted (don't remember which B/G that I am thinking of)
If you go look on JimZ's site where the plans are posted
https://www.dars.org/jimz/k-13.htm
You can see in the illustration right below the parts list that the pylon grain does not go spanwise. Apparently, the pylon balsa stock was provided in the kit already pre-cut. The wing/fin/body patterns shown on the third page of the plans does not include a template for the pylon, another indication that the pylon was not cut from the kit's basic sheet balsa.
These are the things that you forget when it's been 35 years since building one particular kit.
The thicker pylon stock also appears in the front view at the bottom LH side of the second page of instructions. I don't know why Estes designed their kit this particular way but I can testify that the pylon balsa was *not* weak. I flew mine quite a bit and it never broke, even with a good hard landing on the tip of the nose.
 

Planet Andy

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PBurner, Bob,

Thanks again, Yes in the instructions, there is no pattern or directive for cutting the pylon piece except to not feather the gluing surfaces...heck even I knew that. yet (as I read it) it is referred to in the parts list as BFS60S which according to the chart on ninfinger is 3/32" thick. So to reiterate... Astron Scout fin pattern, grain parallel to leading edge of pylon, 3/32" thick... And then Narprez (hail to the chief) there's some great info that the plans don't tell you about. Thank you. hey if it came from HQ I guess I'd better pay attention! I will hopefully have some progress to show all of you on the weekend.

Thank you all again,

Andy
 

Planet Andy

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Originally posted by Andy Turits
So to reiterate... Astron Scout fin pattern, grain parallel to leading edge of pylon, 3/32" thick...
Andy
DOH!

Astron Scout fin pattern, grain fore and aft
3/32" thick

Andy
 

Planet Andy

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Originally posted by Andy Turits
DOH!

Astron Scout fin pattern, grain fore and aft
3/32" thick

Man oh Man,

the Astron Scout plan (on Jim Z) and fin template has the fin balsa at 3/16" NOT 3/32" as part number BFS60S on ninfinger would have us believe. I'm assuming now that this is correct as that is twice the thickness as it seems in the falcon plans. So my final answer?

Astron Scout fin pattern, grain fore and aft
3/16" thick

Andy


....perhaps I should've gone for three fins and a tube for my first scratchbuilt but now I'm determined!
 

powderburner

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I didn't want to say anything before about the 3/32 thickness, after having already revealed the extent of my gray-cell failures on the other design characteristics.
But I think the thicker measurement is right for the Falcon pylon. The Astron Scout fins were pretty thick too, because that thing tumbled down for recovery (with the motor case retained?) and hit pretty hard.
 

BobH48

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Originally posted by powderburner
I didn't want to say anything before about the 3/32 thickness, after having already revealed the extent of my gray-cell failures on the other design characteristics.
But I think the thicker measurement is right for the Falcon pylon. The Astron Scout fins were pretty thick too, because that thing tumbled down for recovery (with the motor case retained?) and hit pretty hard.
Yes, 3/16" is the correct measurement.

I happen to have a set (3) of BFS60S fins and I went and measured them.

EDIT: If you had asked me before I measured them I would have "remembered" them as being 1/4" thick. :rolleyes:
 

kkooch

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M.Bundick wrote:
"The secret to getting good Estes Falcon performance is to put the incidence in the WING. "

Doesn't matter if it's in the wing or in the stab. In order for the glider to track straight up, the wing must be producing a Cl(Coefficient of lift) close to zero. So, if you raise the LE of the wing, on the way up it will assume a near zero aoa and the pod will be at a non-zero or rather negative aoa = lots and lots of drag.

Better to put the incidence in the stab...less drag and higher flights. I've built falcons this way and never ran into boost problems.

Kooch
 

GuyNoir

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Originally posted by kkooch
Better to put the incidence in the stab...less drag and higher flights. I've built falcons this way and never ran into boost problems.
Can you describe how you did this? My Falcons with tail incidence were nice looking, but loopers under power. It got so the NIRA guys would call "heads up" when they saw I had a Falcon on the pad. . .
 

Planet Andy

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Thank You all for your input, when I first got the idea to build a boost glider, I had no idea it would cause such debate... well I'm a wide eyed newbiebar. At any rate, I pretty much built it stock per the instructions figuring that was how it was designed. Along the way I had my doubts if it would fly at all. Now that it is done with fillets drying it looks pretty straight, symmetrical and looks good. Still some sanding to do. At this point I am not going to paint it at all. It's gonna dry all week and weather permitting I'll be able to test it next weekend. I didn't rush the build but I only took one shot of most of the cut balsa pieces. The other three panels are three views as completed. If it doesn't fly too good but survives its tests I'll paint it real nice and it will become a display piece. Hey I learned a lot along the way. Gathered enough materials for more scratch builds also. My favorite part was shaping the wings. I plan on placing a mail order this week and including a boost glider kit or two in there. So here's four pics in one.

Thanks again everybody,

(planet) andy
 

BobH48

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Andy,

Looking good.

When you are ready to test glide and trim it, take a fishing split shot weight and pound it flat with a hammer......real thin.

You can then cut tiny slivers of weight from it and adust the glide using those.
 

Planet Andy

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Bob,

Thanks...I like it, the measurements are exactly to specs! Preliminary testing...I couldn't resist giving it a couple of tosses in the backyard this afternoon, show that it glides very straight without any banking but is a little nose heavy. Smushed down fishing split shot...how is that affixed? Smushed into the wood? A little dab of CA? I was thinking modeling clay.

A T
 

powderburner

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You are definitely going to want to trim this thing with a few slivers of weight out on one wingtip, to make your glider circle.

You might have to experiment with this, to see how well the glider turns and stays over your field. Some designs tend to be more stable than others and want to go straight ahead unless major quantities of trim ballast are used.

I recommend very low-power flights until you get it gliding like you want. If you launch on a C motor and it glides straight ahead, I hope you have inked a return phone number on it somewhere . .
 

Planet Andy

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Originally posted by powderburner
You are definitely going to want to trim this thing with a few slivers of weight out on one wingtip, to make your glider circle.
Trim to circle down....Yes Definetely

I recommend very low-power flights until you get it gliding like you want. If you launch on a C motor and it glides straight ahead, I hope you have inked a return phone number on it somewhere . .
C Motors? Whoa...I've got a bunch of 1/2As that are just a waitin. I can pretty much assume I'll never see it again on a C. Our research department noticed that back when this bird originally flew there were 1/4A standard size engines available.

A T
 

Micromeister

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I like bunny have had good falcons and some rather bad falcons but all in all a great model over the years:)
 

kkooch

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Originally posted by narprez
Can you describe how you did this? My Falcons with tail incidence were nice looking, but loopers under power. It got so the NIRA guys would call "heads up" when they saw I had a Falcon on the pad. . .
I put it in the stab. My point is that it needs some negative incidence to counter the nose down pitching by the motor and to help avoid a death dive after transition. You could put it in the stab or put it in the wing.

Going a step further, imagine your model with positive incidence in the wing with NO stab. This theoretical model would for sure pitch down and fly into the ground. The incidence in the wing on your model causes the stab to fly at a negative aoa and provide the necessary countering moment on boost.

My stab has just a smidge of incidence...perhaps 1/32"

Kooch
 
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