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Jeff Walther
10-29-2008, 06:14 PM
What is the angle of the BFS-60S pylon on the Falcon (K-13)? The 1974 parts catalog lists the BFS-60S as being 1/2" X 3.7". But the thing is not a rectangle. It is a regular parallelogram.

The photos of the Falcon show the upper long edge of the pylon as at least 1/2" shorter than the length of the BT-20J body tube (2.75" long). That would seem to indicate that the bottom long edge of the pylon must travel about 1.5" backward while only going 1/2" down or a tangent of 1/3 which would yield an angle of about 18.5 degrees which seems awfully shallow. The picture makes it look more like 30 degrees. So I'm guessing that the length listed in the '74 catalog may be wrong. The length of the BT-5BJ tube certainly seems to be wrong--either that or Estes used the same designation for different sized tubes in their kits.

Failing an angle measurement, if I could get a confirmation of the total length of the pylon and the length of the long edges, I could draw the rest.

Thank you,

Jeff

Questor
10-29-2008, 07:07 PM
Get the fin pattern for the older Estes Scout. That what was used for the original Falcon kit pylon. Then you would not have to do all that math. :D

Ltvscout
10-29-2008, 08:43 PM
If you're picking up parts from Semroc to clone this, ask Carl/Sheryl if they'll see you one fin from the Scout. That's what the pylon was, a Scout fin.

tbzep
10-29-2008, 08:46 PM
Better yet, buy the whole fin set. You will have one for the rocket and two spares in case something happens. You will be out a total of $1.10 post paid.

Semroc Scout fins (http://www.semroc.com/Store/scripts/prodView.asp?idproduct=1629)

Carl@Semroc
10-30-2008, 12:06 AM
The angle was 22.5 degrees. Since they were cut on a bandsaw, that was a common detent.

Mark II
10-30-2008, 02:07 AM
The angle was 22.5 degrees. Since they were cut on a bandsaw, that was a common detent.
Half of 45 degrees, which is half of 90 degrees, which is... oh, OK, I get it now. :chuckle:

Mark \\.

Jeff Walther
10-30-2008, 09:10 AM
Better yet, buy the whole fin set. You will have one for the rocket and two spares in case something happens. You will be out a total of $1.10 post paid.

Semroc Scout fins (http://www.semroc.com/Store/scripts/prodView.asp?idproduct=1629)

I should have posted this question two weeks ago, *before* I placed my Semroc order. :-) I didn't realize that the Scout fins were the same, otherwise I would have ordered a set. Although, since every item is post paid, I'm not sure there's any disadvantage to me to ordering a set by itself now--and I'd probably think of those six or seven items that somehow escaped my attention on the last order. Or that I just should have ordered more of. For example, I ordered some BNC-5BA nose cones so I can clone the Mars Snooper II once or twice. Well, it turns out that my son is quite taken by those nose cones, so I really should have ordered more of them. I did not factor in the kid-cool factor.

I don't mind having three pylons vs. having one. As you point out, the price is right, and besides, rockets are loss and damage prone. There's just no reason not to have spares.

I'm also arguing with myself regarding the Midget, Beta and Farside fin sets. Make-my-own vs. buy the convenient and affordable pre-cut sets. Decisions, decisions.

Jeff Walther
10-30-2008, 09:26 AM
The angle was 22.5 degrees. Since they were cut on a bandsaw, that was a common detent.

Thank you, Carl. Between that and the earlier suggestions I now have at least three possible solutions. Not a bad situation to be in.

I can:

1) download the Scout fin pattern (Thanks, Questor)
2) Do the math using the 22.5 angle (Questor, but I *like* doing flat geometry problems.)
3) Order the precut Scout fin set from Semroc.

Why does the Scout have such thick fins? The BFS-60S is 3/16" thick according to the '74 parts catalog.

Doug Sams
10-30-2008, 10:15 AM
Why does the Scout have such thick fins? The BFS-60S is 3/16" thick according to the '74 parts catalog.The Scout has tumble recovery. Landing with the added mass of the motor, it needs the extra strong fins. Also, to ensure the destabilizing effect of the motor shifting aft, the added aft wieght of the fins is necessary.

The tumble recovering Sprite also had the thick fins.

BTW, in Estes (old) nomenclature, divide the BFS # by 320 to get the thickness: 60/320 = 3/16.

Doug

.

Chas Russell
10-30-2008, 10:30 AM
IIRC, SEMROC pays postage on orders over $25. So you would have to order the Scout fins and a bunch of other stuff, too! Darn the luck.
Already working on another order. Not thrilled that the Estes "releases" for next year do not use the correct body tubes. Will have to order some SEMROC parts to clone them early.

Chas

Jeff Walther
10-30-2008, 11:47 AM
IIRC, SEMROC pays postage on orders over $25. So you would have to order the Scout fins and a bunch of other stuff, too!

<chuckle> Oh, what a terrible burden to bear!

BTW, where can you find the minimum? I've searched the site a couple of times looking for shipping terms and such and never found a page for it. Of course, that doesn't mean that I didn't overlook it, but it does mean that either it isn't in the usual places or I have repeatedly had very senior moments while visiting the site.

Mark II
10-30-2008, 11:57 AM
I cut the Scout fins myself for my K-1 clone and cut another one for my Astron Falcon clone. No biggee. But, I have to tell you, those precut fins that came with my Golden Scout kit were REALLY NICE! :D If you have a bunch of other stuff that you need (and don't we all? ;) ) and you are putting together another order to Semroc, I'd recommend adding in a set of Scout fins.

If not, you could pick up some 3/16" x 1/2" balsa strip from your local hobby shop or craft store (e.g., Michael's) and cut the fins from that. This way, you will know that the two long sides are parallel and square.

Mark \\.

Chas Russell
10-30-2008, 12:14 PM
Since I have placed many orders with SEMROC, I hadn't really thought about the minimum. I found the information when I went to "account" and "payment policy".

I must apologizefor my faulty memory, but the actual minimum order for no postage is just $10. Sorry Carl, tried to get everyone to buy a minimum of $25! That section also contains information on payment methods and group discounts.

So order ten sets of Scout fins...

Chas

Jeff Walther
10-30-2008, 12:36 PM
Since I have placed many orders with SEMROC, I hadn't really thought about the minimum. I found the information when I went to "account" and "payment policy".

Okay, I found it. Yay. I had to log into my account, click on my old order and then click on "Payment policy". I'm not sure how someone who has never created an account, nor placed an order would get to that page.

I must say, a $10 minimum is very kind. Shoot, three or four nose cones, or three to eight fin sets, or six or seven centering ring sets. It's not hard...

barone
10-30-2008, 02:45 PM
Okay, I found it. Yay. I had to log into my account, click on my old order and then click on "Payment policy". I'm not sure how someone who has never created an account, nor placed an order would get to that page.

I must say, a $10 minimum is very kind. Shoot, three or four nose cones, or three to eight fin sets, or six or seven centering ring sets. It's not hard...
Don't worry....if you try to place an order under $10, you won'be permitted to check out and they tell you why..... :o

Jeff Walther
10-30-2008, 03:33 PM
If not, you could pick up some 3/16" x 1/2" balsa strip from your local hobby shop or craft store (e.g., Michael's) and cut the fins from that. This way, you will know that the two long sides are parallel and square..

Well, I had one of those 40% off coupons burning a hole in my pocket and I was eating lunch across the street from Hobby Lobby any way. So I stopped by and used the coupon on a bottle of dope thinner and picked up a strip of 3/16" X 1/2" basswood. Hmmm, will the balsa vs. bass make any substantial difference? I like the feel of basswood better as it seems somewhat more durable while still being lightweight. In fact, I thought I was buying balsa several times but now that the difference has entered my awareness, I've noticed that several pieces of stock I have at home are actually basswood rather than balsa wood. At least, that's how they're labeled.

My (new) bottle of Sanding Sealer seems awfully thick. Hence the thinner. After painting fins with it, they look like they've been dipped in clear plastic. My ancient bottle of Aerogloss Balsa Filler is much more polite. It is a *lot* less work to sand off the balsa filler than it is to sand off the sanding sealer.

Mark II
10-30-2008, 10:09 PM
Weight is everything in a glider. Trimming and balancing any glider can often become a matter of a small fraction of a gram, so the substitution of a denser material like basswood here or there could make trimming the model to achieve a good glide anywhere from a little bit to a lot more complicated. The engine pylon on your glider is not one of the larger parts, but it is not insignificant, either. The Astron Falcon, whose design was taken straight from a HLG, is said to be an excellent flier. (I haven't flown mine yet, so I hope those reports are right. :D ) So it is probably much more forgiving than many other designs. One argument for using basswood for the pylon is that it will probably make it more resistant to being sheared off by a hard impact with the ground. But whether or not your model will need that extra protection will depend on how well you build the rest of the glider. ;) :chuckle:

Mark \\.

Carl@Semroc
10-31-2008, 09:07 AM
Okay, I found it. Yay. I had to log into my account, click on my old order and then click on "Payment policy". I'm not sure how someone who has never created an account, nor placed an order would get to that page.

I must say, a $10 minimum is very kind. Shoot, three or four nose cones, or three to eight fin sets, or six or seven centering ring sets. It's not hard...Thanks Jeff,

It WAS on the site somewhere else long ago, I am almost certain... I think. :o

The link is now on the Information page to the terms and conditions (http://www.semroc.com/Store/Scripts/termsAndCond.asp) page.

LeeR
10-31-2008, 11:01 PM
BTW, in Estes (old) nomenclature, divide the BFS # by 320 to get the thickness: 60/320 = 3/16.

Doug

.

I never knew that! OK, now give us the equation for mapping BT numbers to tube diameter.
:)

Jeff Walther
11-06-2008, 03:30 PM
I may have overlooked it before, but I just noticed that Semroc now has the laser cut fins for the Falcon listed. I'm pretty sure that's recently added. Also, a single Scout fin is listed for $.40 in addition to the set of three for $1.10.

Thank you, Carl. That's mighty responsive of you!

Not exactly topical, but I didn't think that the Sky Dart was up there before either and it's there now. Maybe I just never looked at the LCF list carefully enough. The Sky Dart is on my list somewhere not too far behind the Falcon.

Carl@Semroc
11-06-2008, 04:11 PM
I may have overlooked it before, but I just noticed that Semroc now has the laser cut fins for the Falcon listed. I'm pretty sure that's recently added. Also, a single Scout fin is listed for $.40 in addition to the set of three for $1.10.

Thank you, Carl. That's mighty responsive of you!

Not exactly topical, but I didn't think that the Sky Dart was up there before either and it's there now. Maybe I just never looked at the LCF list carefully enough. The Sky Dart is on my list somewhere not too far behind the Falcon.Thanks!

Over the past few weeks, I have noticed that many were not online that we have in stock. There is a complete list that updates itself from the database, but there was no link to it.

Semroc Laser-cut fins (http://www.semroc.com/Store/products/finsel.asp)

Ltvscout
11-06-2008, 07:01 PM
Semroc Laser-cut fins (http://www.semroc.com/Store/products/finsel.asp)
Whoa! Great link. Thanks, Carl!

tbzep
11-06-2008, 07:04 PM
Thanks!

Over the past few weeks, I have noticed that many were not online that we have in stock. There is a complete list that updates itself from the database, but there was no link to it.

Semroc Laser-cut fins (http://www.semroc.com/Store/products/finsel.asp)

When are the "back ordered" ones going to get burned? I've hit a lazy streak and don't feel like fighting with templates that don't print out the correct size. :rolleyes:


.

Jeff Walther
11-06-2008, 10:11 PM
There are two entries for the Orbital Transport with different part numbers. What is the difference?

Also, are the Midget fins for the original shorty version or for the mini-engine version? I think the fin shape would be a little different because the sustainer fins followed a BT50 to BT20 taper (?) on the shorty (original) version and a BT20 to BT5 taper on the mini-engine version. I guess the angle and length of the taper might be the same for both versions though. Hmmm....

blackshire
03-12-2009, 08:03 PM
I'm itching to order a set of Falcon parts from Semroc (still saving up!). The original Estes Falcon used a lead disc weight glued to the back of the BNC-20A nose cone to achieve a "coarse" trim balance, so a heavier pylon made of basswood or Tung wood (the wood used in Apogee Components' Chinese Sky Rocketry Condor boost-glider kit) could serve as "built-in ballast" to replace the lead disc.

Also, making the horizontal portion (or the vertical portion) of the "T-section" fuselage boom out of basswood or Tung wood might make it strong enough--at the cost of extra weight--to resist being broken by wayward ejecting motor cases.

Weight is everything in a glider. Trimming and balancing any glider can often become a matter of a small fraction of a gram, so the substitution of a denser material like basswood here or there could make trimming the model to achieve a good glide anywhere from a little bit to a lot more complicated. The engine pylon on your glider is not one of the larger parts, but it is not insignificant, either. The Astron Falcon, whose design was taken straight from a HLG, is said to be an excellent flier. (I haven't flown mine yet, so I hope those reports are right. :D ) So it is probably much more forgiving than many other designs. One argument for using basswood for the pylon is that it will probably make it more resistant to being sheared off by a hard impact with the ground. But whether or not your model will need that extra protection will depend on how well you build the rest of the glider. ;) :chuckle:

Mark \\.

blackshire
03-12-2009, 08:15 PM
Another thought just came to mind. Heavy gliders such as the Centuri Mach 10 do better on windy days, so a heavier all-basswood (or all-Tung wood) Falcon might be a good windy-day boost-glider. One could have a matched fair weather/foul weather pair of them made of balsa and basswood (or Tung wood), respectively.

Mark II
03-12-2009, 10:18 PM
Another thought just came to mind. Heavy gliders such as the Centuri Mach 10 do better on windy days, so a heavier all-basswood (or all-Tung wood) Falcon might be a good windy-day boost-glider. One could have a matched fair weather/foul weather pair of them made of balsa and basswood (or Tung wood), respectively.
I would think that the Falcon (and Semroc Hawk) would glide well without the need for much trimming. Yes, it would need a little, but probably not that much. (Unlike, say the Invader.)

The fuselage on my Falcon seems to be quite strong; the "T" construction (and my use of hard C-grain balsa for it) produced a sturdy structure. I am much more worried about how the wings are going to hold up. I used 30-min. epoxy in the construction, and I also used thin CA as a sanding sealer on all of the surfaces. Usually I leave all the balsa surfaces on my gliders bare, but I thought that I would give the CA a try. I still haven't trimmed it yet, but with the nose weight that I have provisionally placed in it, my Falcon weighs 20 grams.

MarkII

blackshire
03-13-2009, 12:54 AM
I would think that the Falcon (and Semroc Hawk) would glide well without the need for much trimming. Yes, it would need a little, but probably not that much. (Unlike, say the Invader.)

The fuselage on my Falcon seems to be quite strong; the "T" construction (and my use of hard C-grain balsa for it) produced a sturdy structure. I am much more worried about how the wings are going to hold up. I used 30-min. epoxy in the construction, and I also used thin CA as a sanding sealer on all of the surfaces. Usually I leave all the balsa surfaces on my gliders bare, but I thought that I would give the CA a try. I still haven't trimmed it yet, but with the nose weight that I have provisionally placed in it, my Falcon weighs 20 grams.

MarkII

The Falcon has a fairly low wing loading, so it "bobbles" around in breezy conditions that the heavier Mach 10 can penetrate. The Invader isn't supposed to glide--it has the authentic UFO "falling leaf" motion! :-)

With even judicious amounts of aliphatic resin glue (yellow wood glue) the Falcon's four wing/fuselage bonding lines make its wings pretty resistant to "striptease" under power, so the 30-minute epoxy you used should be more than strong enough. One area that could use a thin strengthening coat of either CA or yellow wood glue is the pylon, because its grain (parallel to the motor mount tube and to the fuselage) can break from the acceleration or ejection charge forces, as happened to my father's Falcon. (If I were cutting out my own Falcon parts "from scratch," I'd orient the pylon's balsa grain so that it would be parallel to the pylon's "slant-cut" front and rear edges.)

barone
03-13-2009, 07:46 AM
Seems some card stock laminated over the pylons would be sufficent to strengthen them....

Mark II
03-13-2009, 07:50 PM
I'm not worried about the wings on my Falcon stripping off during the flight - I'm worried about them shearing off when it lands. They are quite thin.

I know what you are saying about the orientation of the grain in the pylon. Funny, but the pylon appears to be the strongest part. The pod attached to it has so little mass when it is empty, that I can't imagine it striking with enough force to shear off. But of course I have no experience flying it yet, or anything like it, so who knows...

BTW, here is a picture - it's the bigger one in the shot. ;) I STILL haven't gotten around to attaching the fin rudders yet. (Geez, I hope I can find them! :eek: ) :chuckle:

MarkII