A 75mm MD Wildman Falcon kit showed up today, let's take a look

Disclaimer: This will be my long term build thread, and this one is at the bottom of the pile so it'll take a minute! Since this is a new and relatively exciting kit with little info online I figured someone else might want to see what it includes.

I've been under 10-12k waivers for a few years so despite my love of other people's high performance flights I have gotten quite a pile of unbuilt minimum diameter birds. As it turns out I have to move to Kansas later this year, and since I understand that there are a couple of launches in that region with waivers above 12k it seemed justifiable to buy yet another damn set of composite tubes and plates.

The Falcon is a 75mm/3" carbon fiber and fiberglass minimum diameter rocket designed for head end deployment. The kit is pretty minimalist but it's not exactly uncharted territory to figure it out; build an avionics setup, shove a parachute in the nosecone, and glue the fins on with the recommended scotchweld right? Well I'd like to be a tad more deliberate about things as I stick this one together, so before anything gets sanded or glued there are a few problems I'd like to solve:

[] Get an accurate sim file together (me)
[] Figure out a recovery system that will be appropriate to altitudes flown (Review Jim
Jarvis' document on BP charge effectiveness at higher altitudes, see what other people have done for shear pins in this performance range)
[] Design and manufacture an electronics sled and arrangement to facilitate dual redundancy and tracking in an elegant manner (me)
[] Do some further research on the specific concerns associated with the intended adhesive and materials (me doing research, hopefully someone else already did the heavy lifting)
[] Motor forward bulkhead/retainer (probably just copy the standard coupler and pem nuts design)

The important problems I can hopefully ignore (because this kit was designed by someone who knows better) are aerodynamic stresses like fin flutter and peel strength of the tube.

Here's what your money gets you:


Here's what everything weighs (pre-wash/sanding):

52" body tube


7" fg coupler


Nosecone (no tip)


4 fg fins:

They were 93,94,95,95.

NC Tip and hardware:


Bulkplates:


Adding it up:
73g 2 aluminum bulkplates
796g 52" carbon fiber body tube
236g nosecone without tip
33g nosecone tip, washer, nut, and 1/4" welded eyebolt
127 7" fiberglass NC coupler/avionics bay
376g 4 fiberglass fins 3/16" at root, no taper but steeply beveled

That's a total of 1641g or 3.6lbs. I think the advertised predicted weight was a bit under
3lbs so we're about 270 grams heavy give or take. It's still light enough for me!



My 52" body tube is about 52 1/8". Here it is next to a 75/7600 case.



Just over 11" between the top of the motor and the end of the tube (ignoring the extra distance if a thrust ring is used). Assuming at least half of the coupler sticks down into the body tube we're probably going to have about 6" of space for the drogue, harness, hardware, and motor bulkhead. The unmeasured eyeball-accurate sim file I made based on the spec sheet called it a no motor weight of 7.2lbs going to 42k on an M2245. Once I get a better file together I'll attach it here.

Now it's back to my pile of Blackhawks and Mongeese so I can make smaller scale mistakes before destroying this one!

Disclaimer: This is not meant to be inflammatory, so don't lose your crap. Whenever I comment on WM stuff I get accosted.

Okay, with that out of the way...this appears to be a Punisher with a longer tube made out of CF, an extra fin, fin guides for a lot more money. In your opinion, do you think the value is there?

What are your concerns with flying the plastic nosecone beyond Mach 2?

Lucky for you my emotions are not tied to any brand loyalty.

The honest answer to the question about value is "it depends" or "I don't know." The Black Saturday sale price was nearly $200 less than the current price of the kit, but still a lot more than buying the parts probably would cost, which means that what the buyer is really paying for is that some other guy did the engineering legwork to say the airframe would survive as issued in a high performance flight. I'm not an engineer and sometimes have more money than sense/time, so I feel no ill effects from the purchase. Could any of us achieve the same thing with open source research and a little elbow grease for cheaper? Of course.

Since it's new and nobody else has posted their experience with one, perhaps our discussion will serve to dissuade those looking for better dollar value and tantalize those looking for better time value.

The nosecone is an excellent thing to bring up and I welcome anyone's experience. I know I've seen some other smart people on here (Jeroen_at_CTI) claim to have flown the polycarbonate/phenolic cones successfully at over M2, but I'll need to do more digging to find numbers.

[edit] Jim Hendricksen claimed in 2014 when introducing the smaller (38/54) polycarbonate nosecones that they were good to M4.5. I think his claim was based off of a projectile use of the same material, which is not necessarily a scientific way of proving that this NC design would work for a given flight regime, but for flights where you're spending a short time between M2-M3 it seems that the material at least should survive the heat. I'll update if I find anyone who has actually flown one at multiple mach

I would have thought the fins would be a machined airfoil, ala Space Cowboy, are they?

Looks real nice to me. Regarding the cost, I am sure that at least part of what you are paying for is the time and name of Dr David Reese.

watermelonman said:

Looks real nice to me. Regarding the cost, I am sure that at least part of what you are paying for is the time and name of Dr David Reese.

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Right, for the fins. He designed the Punisher (Space Cowboy) fins as well.

Smapdiage9 said: " I'm not an engineer and sometimes have more money than sense/time". Ha. I read that as "I am an engineer and have more money than sense."

Sorry. Didn't mean to project!

MarkH said:

Anyway, I plan to fly on an AT L2200 which should hit around Mach 2.2, so I guess sooner or later someone will find out what the speed of these FG infused polycarbonate nose cones is.

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I have had an extended punisher out to Mach 2.3 on a Loki L2050. Looks no worse for wear than new.

Dennis

dixontj93060 said:

I would have thought the fins would be a machined airfoil, ala Space Cowboy, are they?

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No, they are steeply beveled parallel to the leading edge about an inch+ wide.

patelldp said:

Right, for the fins. He designed the Punisher (Space Cowboy) fins as well.

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Right you are. Also on the value discussion, it seems worth noting that the full price is about the same as comparable 75mm CF kits (https://rocketrywarehouse.com/product_info.php?products_id=1419) and less with the wm club.

Igotnothing said:

Smapdiage9 said: " I'm not an engineer and sometimes have more money than sense/time". Ha. I read that as "I am an engineer and have more money than sense."

Sorry. Didn't mean to project!

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I'm the guy who reaps the benefits of what the engineers do and then complains to them when I break it.

Dwatkins said:

I have had an extended punisher out to Mach 2.3 on a Loki L2050. Looks no worse for wear than new.

Dennis

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Great to know! Thanks.

One of the things making these tubes unique:

They are made of carbon uni pre-preg, qausi-isotropic convolute wound carbon fiber tube, 6 layers if I remember correctly.
Then covered with 1 final wrap of cloth to give it the "carbon" look. If left just uni, it would be plain black with no texture look.

Uni requires some special handling, and is VERY expensive.
It comes frozen and must be kept at 0 to -10 degrees....requiring a designated freezer to keep it in, and special heat treating equipment to cure it in.
Shelf life is approximately 6-10 weeks. There is a lot of waste during wrapping the mandrel, as it is laid up in several orientations.

The sheet is oriented at 0, 45, 90 etc. every layer changing.
They are then wound with a proprietary covering and process to ensure proper pressure during cure and bonding between layers.
Then it must be heat cured in an oven, requiring a several hour ramping up of temperature, then down during the process.
These are NOT spiral nor convolute wound, with a cover layer, as some thought.

The end result is truly a tube & coupler, of true aerospace quality & strength, light weight.

I know of no other tubes being made this way at this time for our high power needs.
The fins are G-10. One probably wonders why?
D.Reese determined that using G-10, rather than carbon plate, would result in a better combination of resonance frequencies & harmonics between the tube & fins further reducing the chance of fin flutter in the range of speeds this rocket was designed to fly in.

Yes... it is expensive....and so is the process to make these very labor intensive.
So if you plan on really pushing the boundaries of flying, only then can you determine its value.
Not for the faint of heart, or anyone desiring a Ferrari to only drive it 70mph.

So there ya have it.:dark:

Ps: I am working with the manufacturer on a project that may reach speeds up to M-4 utilizing tubes of 10in. diameter & 4.5 in diameter. Surface temps over 1100 degrees.....these tubes are the only ones we could find that match our needs. Designed totally from the ground up, just for this type of use, by him. Months of research went into this, before the first tube was made, & how do you put a price on that.......you can't

DizWolf said:

Not joking or being an ass, I'd love to see the math on that.

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Dr Reese would have to provide that, I was in the same camp as you......till he explained it. Way over my pay grade.
Since he no longer frequents this Forum, maybe some one else could fill us in.
Remember the kit is also provided with carbon cloth to attach the fins, they are not held on, by only fillets.


Edit: I am incorrect on ultizing carbon cloth with kit, it does NOT.
I remembered earlier discussions & did not realize in final form deemed unnecessary.

blackjack2564 said:

Dr Reese would have to provide that, I was in the same camp as you......till he explained it. Way over my pay grade.
Since he no longer frequents this Forum, maybe some one else could fill us in.

Remember the kit is also provided with carbon cloth to attach the fins, they are not held on, by only fillets.

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Quite interesting. It's different, Which may not always be a bad thing.

blackjack2564 said:

Dr Reese would have to provide that, I was in the same camp as you......till he explained it. Way over my pay grade.
Since he no longer frequents this Forum, maybe some one else could fill us in.

Remember the kit is also provided with carbon cloth to attach the fins, they are not held on, by only fillets.

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Jim,

Thanks a lot for the background info, they should put more of that on the website.

FYI: Mine didn't come with any cloth and I assumed from the spec sheet asking for big fillets on a specific epoxy that they were surface mount only. Also the coupler I got seems pretty clearly to be fiberglass not carbon.

This is why I asked the question. The forum is quite possibly the largest audience and cheapest source of marketing in the hobby. I carefully asked the buyer his opinion of the value he received as compared to the price. Good discussion ensued, up to prospective buyers to decide now.

The manufacturer of this kit also bumped my Yard Sale post for my 29/480 motor! Thanks!

smapdiage9 said:

Jim,



FYI: Mine didn't come with any cloth and I assumed from the spec sheet asking for big fillets on a specific epoxy that they were surface mount only. Also the coupler I got seems pretty clearly to be fiberglass not carbon.

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Let me clear some things up.

Coupler I am referring to comes with the PAYLOAD version kit.
Standard Falcon uses a fiberglass coupler in nose cone av-bay for radio transparency.

I edited my previous post as I was mistaken about coming with carbon cloth.
In early talks it was going to be provided, later deemed unnecessary, due to using the type of epoxy recommended.

Finally the nose cone is "plastic" technically, but truth be told it is a chopped fiberglass infused polycarbonite [high temp] similar to that being used in fighter jet canopies, and the outer shell on specialty 20-30mm cannon rounds, which do travel at speeds over M-3

Thanks for the clarification. I guess I have no choice now but to remain totally stoked about flying this thing!

Man does this thing sound insane...
That's my thing,, super attention to detail, ,
extremely well thought out,, through and through. ....
This is really tempting. ...

Teddy

Does anyone have an accurate sim file for this rocket? I have looked, and can't find one.

Thanks

I can get you the fin dimensions.

ChrisAttebery said:

I can get you the fin dimensions.

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I'd appreciate that. That is really the only missing piece. Thanks.

Root: 8.5"
Tip: 1.75"
Height: 3.375"
Sweep: 7.375"
Thickness: .188"

There's about a 3/4" bevel on the leading edge only. The leading edge is about .080" wide. Needless to say the bevels could be improved.

ChrisAttebery said:

Root: 8.5"
Tip: 1.75"
Height: 3.375"
Sweep: 7.375"
Thickness: .188"

There's about a 3/4" bevel on the leading edge only. The leading edge is about .080" wide. Needless to say the bevels could be improved.

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Chris, are the Falcon fin dimensions identical to your modified Blackhawk 75 fin set? And for the "loaded" question, do you think this fin design (in a 4 fin configuration) is a truly optimized fin design for a 75mm minimum diameter airframe?

truly optimized fin design for a 75mm minimum diameter airframe

Clearly no.....but maybe a very good compromise when starting with flat plates as stock and just beveling edges.....

FredA said:

truly optimized fin design for a 75mm minimum diameter airframe

Clearly no.....but maybe a very good compromise when starting with flat plates as stock and just beveling edges.....

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OK, so excluding space cowboy machined airfoil fins. Or including them. FredA, what is your "ideal" optimized fin design for 75mm minimum diameter 4 fin rockets?

plugger said:

OK, so excluding space cowboy machined airfoil fins. Or including them. FredA, what is your "ideal" optimized fin design for 75mm minimum diameter 4 fin rockets?

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That is a really loaded question. It is likely a clipped delta of some dimension that include the machines airfoil. The dimensions depend on the rocket and its planned flights.


Sent from my iPhone using Rocketry Forum

"FredA, what is your "ideal" optimized fin design for 75mm minimum diameter 4 fin rockets? "

I'll be flying a 75mm Min-D 4FNC CF rocket at Balls.
Fins are mixed CF and FG layups done in a mold to make fins that follow NASA's NACA profile.
I'd have to go back and dig through my notes to tell you which exact profile.
But since I don't have a wind-tunnel at my disposal, I figure NASA's work would have to be sufficient.

So...in I guess that's your answer..................."NACA Profile"

BTW: Flying on a 7% N-1850 using my Kosdon 10k case....should be fun!

ChrisAttebery said:

Root: 8.5"
Tip: 1.75"
Height: 3.375"
Sweep: 7.375"
Thickness: .188"

There's about a 3/4" bevel on the leading edge only. The leading edge is about .080" wide. Needless to say the bevels could be improved.

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Thanks. Exactly what I needed.

Keep in mind that I've only done ONE 54mm minimum diameter flight. I've got 3 M flights on my Punisher 4. I'm not a trove of knowledge. I read a lot, I think a lot, I sim a LOT and I do have a good feel for "That Looks About Right" engineering. :wink:

The Falcon fins are are close to mine, but not exact. Mine are actually a little longer and have a little more sweep (both leading and trailing edges). I simmed a LOT of designs in both OpenRocket and RASaero II before I settled on one.

IMHO the Falcon fins could be thinner but you'd have to add tip to tip if you did. I think the bevels could be longer, sharper and on both leading and trailing edges too.

plugger said:

Chris, are the Falcon fin dimensions identical to your modified Blackhawk 75 fin set? And for the "loaded" question, do you think this fin design (in a 4 fin configuration) is a truly optimized fin design for a 75mm minimum diameter airframe?

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After reading CJ's explanation of the materials, I now want one of these kits!! Sounds like a unique kit with amazing potential, and worth the $$$'s from my perspective.

Viperfixr said:

After reading CJ's explanation of the materials, I now want one of these kits!! Sounds like a unique kit with amazing potential, and worth the $$$'s from my perspective.

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You and me both.