Altitude record attempt using the O3400 in minimum diameter style.

Alex - Post #28 "By doing it that away it may break Argoina's 50,000' waiver and that cannot happen."

Zebedee said:

Alex - Post #28 "By doing it that away it may break Argoina's 50,000' waiver and that cannot happen."

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Zebedee, see the bolded text.

Lots of dead space in your design, are you trying to break the alt record or really break it? Cause I doubt anything under 50K will stick for long. Put the NC right on top of the motor and come fly with us at blackrock!
Also, those are some monster fins! 5.875 spans on a 4in MD....

Alex

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Andrew,
I understand you are close to Argonia but is going to a site with a higher wavier not an option for you?

Andrew,
I understand you are close to Argonia but is going to a site with a higher wavier not an option for you?

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Its already an expensive hobby. If I used my money to drive to Black Rock to fly I would not have any money to actually get the motor and build the rocket. Someday I will but until that point Argonia is the place for me. But if you want to pay for me to drive out there I will. Its like a 1200 mile trip for me and my truck and trailer get 9mpg.

andrewlathrop87 said:

Its already an expensive hobby. If I used my money to drive to Black Rock to fly I would not have any money to actually get the motor and build the rocket. Someday I will but until that point Argonia is the place for me. But if you want to pay for me to drive out there I will. Its like a 1200 mile trip for me and my truck and trailer get 9mpg.

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Haha, tell Mat more about the cost to drive to Black Rock, I'm sure he's eager to hear (we just got back from Black Rock, he drove 1900 miles each way towing a UHaul).

Good luck with your project, we just flew a 4" MD at Airfest with a similarly massive fin span (6") for the same reason, to keep it well under the waiver. [video=youtube;lV5o9YWWrHo]https://www.youtube.com/watch?v=lV5o9YWWrHo[/video]

Good luck with your project, we just flew a 4" MD at Airfest with a similarly massive fin span (6") for the same reason, to keep it well under the waiver

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What motor was that? All Composite? How many layers of reinforcement?

andrewlathrop87 said:

What motor was that? All Composite? How many layers of reinforcement?

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Motor was my own using a formula from a good friend of mine. Composite cased motor, fincan was simple G10 core with 3 layers of 5.7oz carbon vacuum bagged.

Ok cool! How many newton seconds was the motor? What Mach number did it reach to? I am trying to get a baseline in reference to my design and using the CTI O3400.

andrewlathrop87 said:

Its already an expensive hobby. If I used my money to drive to Black Rock to fly I would not have any money to actually get the motor and build the rocket. Someday I will but until that point Argonia is the place for me. But if you want to pay for me to drive out there I will. Its like a 1200 mile trip for me and my truck and trailer get 9mpg.

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prophecy said:

Haha, tell Mat more about the cost to drive to Black Rock, I'm sure he's eager to hear (we just got back from Black Rock, he drove 1900 miles each way towing a UHaul).

Good luck with your project, we just flew a 4" MD at Airfest with a similarly massive fin span (6") for the same reason, to keep it well under the waiver. [video=youtube;lV5o9YWWrHo]https://www.youtube.com/watch?v=lV5o9YWWrHo[/video]

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andrewlathrop87 said:

Ok cool! How many newton seconds was the motor? What Mach number did it reach to? I am trying to get a baseline in reference to my design and using the CTI O3400.

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Haha thats too funny… I do slightly remember it being expensive, with a MD all composite N5800 and all the over nighters in places like Las Vegas. Do you take MasterCard because that is priceless. Nonetheless I would rather save and wait vs clipping the wings off my bird, suum cuique. Oh and Steve it was about a ~5500+ mi round trip but well worth it.

That motor was around 15,000Ns and the mid Mach 2 range. The true numbers are unknown. I would expect yours to go in the high Mach 2 range.


Mat

So what do you guys suggest is the best fin material for high speed min diameter flights? I know G10 is easily obtainable but there are others i am sure.

andrewlathrop87 said:

So what do you guys suggest is the best fin material for high speed min diameter flights? I know G10 is easily obtainable but there are others i am sure.

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Carbon fiber or aluminum. Titanium would be nice but obviously that is incredibly expensive.

I have 3/16 inch g10. I think I am gonna put on 2 layers of 5.7 oz 2x2 carbon fiber on each side of the fins. Followed by 3 layers of 4 oz S-Glass T2T.

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This is my custom order from Gary T at Proline from Curtis. Its all black Profusion. 66 inch booster, 24 inch payload, 12 inch coupler, 1 inch switch band, 5:1 Conical nosecone. 2 fin alignment jigs, 3 custom fins 3/16 inch beveled. I cleaned the parts in the shower with soap and water. Then wiped down with Acetone. I plan to cut the booster down so I wanted a 66 inch for flexibility. I may cut the payload section down. I weighed all the parts and without epoxy, T2T, electronics, and recovery it comes in at 10.4 pounds. I am gonna place fins 2 inches from aft end.

That is some serious rocket porn right there... Nice.

I got the fins finished. I vacuum bagged the fins. The fins are Black G10 3/16" thick. I laid down 2 layers of 5.7oz 2x2 twill carbon fiber from US Composites and using Aeropoxy. I used a big flat of sheet of glass about 4 ft by 4ft. I used that as the backing for the fins. They turned out really good. So each fin has 4 layers. Once I get the fins attached to the airframe I am gonna use 3 layers of 4 oz S-glass from US Composites. I am doing it this way because the Carbon Fiber is rigid and will age rigidity to the already strong G10. Then I am using the fiberglass for the T2T because it is more flexible than the CF. It will allow some "give" for the fins under load/stress rather then T2T CF.

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Fin flutter is likely going to be your enemy at the speeds you are going. High root length to span fins, and thin fins are much more susceptible to fin flutter. If you do not know what fin flutter is, it is usually a two dimensional oscillation in the fin, length wise and width wise. The most common symptom you will see when you get it back is your fin will be gone...

A big component to how likely your fins are to flutter is the shear modulus (~stiffness) of this fins, higher the better. Fiberglass has about 1/3 the shear modulus vs. carbon fiber.

If you are interested in fin flutter here is a NACA report on it. https://naca.central.cranfield.ac.uk/reports/1958/naca-tn-4197.pdf
It may be from way back in the NACA days but, they built the equations empirically.

Xrain said:

Fin flutter is likely going to be your enemy at the speeds you are going. High root length to span fins

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What kind of ratio is considered "high"?

MarkH said:

I don't see a lot of commets, so I'll give my two cents.

I think you want the fin can to be as stiff as possible, and not have some degree of flexibilty, so I don't see any benefit in using fiberglass for the tip-to-tip over CF, except for cost. I'd use the CF.

Also, if you are trying to limit your altitude to stay under a waiver, by using 3 relatively large fins, you could accomplish the same goal (more drag) by using four smaller fins. Four fins with shorter span are more likely to hold together, for a flight going mach 3.

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+1000

Alex

The reason why I am doing it this is I am using my best judgment. I have been talking to am guy here on the forum and he also is a vendor in our hobby. After talking with him this is what he suggested. He has flown min diameter past Mach 4 with successful results. I just wanted to do 3 layers of 5.7oz 2x2 twill on my bird, but he recomemded doing it this way. He said doing 2 layers of CF on each side of fin before attaching fin to airframe. Then he said once fins are on do 3 layers of T2T using 4 oz S-Glass. Also, when attaching the fins to the airframe using Kevlar bulp with high temp epoxy. So I am just taking his suggestions. Right or Wrong IDK I am just trying to take a fresh aproach using all the knowledge from people in our hobby. His fin suggestion was using nomex honey comb with g10 then carbon, but since I already had the G10 fins he suggested I do what I did in the previous post.

Cool. Sounds like you're in good hands. Looking forward to the build!

andrewlathrop87 said:

The reason why I am doing it this is I am using my best judgment. I have been talking to am guy here on the forum and he also is a vendor in our hobby. After talking with him this is what he suggested. He has flown min diameter past Mach 4 with successful results. I just wanted to do 3 layers of 5.7oz 2x2 twill on my bird, but he recomemded doing it this way. He said doing 2 layers of CF on each side of fin before attaching fin to airframe. Then he said once fins are on do 3 layers of T2T using 4 oz S-Glass. Also, when attaching the fins to the airframe using Kevlar bulp with high temp epoxy. So I am just taking his suggestions. Right or Wrong IDK I am just trying to take a fresh aproach using all the knowledge from people in our hobby. His fin suggestion was using nomex honey comb with g10 then carbon, but since I already had the G10 fins he suggested I do what I did in the previous post.

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Its Robert from AMX

Andrew your fins after all the layers will probably be somewhere close to 0.25" so flutter should not be an issue with the materials that you have selected and the respected thickness. I doubt this rocket will go to M3 but might get close… I agree with Marks statement in regards to 4 smaller fins being more survivable (they should experience less aero loads) and they also should provide more dynamic stability than 3 fins (especially on high Mach flights). However depending on the design 4 fins will not necessarily restrict your maximum altitude (at least to a degree of concern for me). That tubing looks to be standard wall thickness and I would put it in the same category as the fins in the sense of a possible failure point (buckling). Nonetheless I think whatever the outcome, you will learn a lot of valuable information and I look forward to your results.

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The fin can is done for tacking on the fins. I have one fillet done. I ran out of 4500 high temp epoxy. I have epoxy on order from wildman. I should get it next tuesday. If so, my plan is to have the fillets done by next Wednesday. Then I will start T2T

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This is a paint scheme I may do for Ode to Texas A&M University. The maroon and white

What's the point of painting a rocket designed for M3/4? It will just burn off leaving a mess.

What's the point of painting a rocket designed for M3/4? It will just burn off leaving a mess.

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Hey Amell I have a question for you. Do you clean your toilet at your house? Why? Its just gonna get dirty again?

The paint scheme does more than look nice, if you did not already know the paint will protect the surface of the rocket. If I am gonna use heat paint for the paint scheme why not make the rocket look good anyway!!

amell said:

What's the point of painting a rocket designed for M3/4? It will just burn off leaving a mess.

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Perhaps not entirely true. There are paints that can handle low M3 flights (which his flight will most likely be under), look at the Mad Max rocket post flight pictures. PGP acrylic 2 pack paint (as used on Mad Max), Unicolor 2k 2 pack, and VHT just to mention a few that I know. Even if some of it comes off it seems to me (might be wrong) that it would eat up some valuable energy that could cause more damage to the underlying structure in the process of burning away. Also it is important to note that the these paints all require elevated heat for curing (even the VHT).

Hey guys I have some news. I know at Mach 3 the heat is at a maximum. Well I know they make paint that is heat paint but to get the full effectiveness of it, it must me post cured. Well I have a different approach. My dad has a gunsmith friend who has some ideas. He is certified to apply this. It is a ceramic coating that cures at ambient temperature. It takes 5 full days to cure but after it is cured it is rated at taking up to 1200 degrees Fahrenheit. The advantage of this you dont have to post cure the rocket and that is a good thing because to post cure it could damage the rocket itself. The paint costs $10 per oz. It wont be till spring. So if the rocket can stay together heat will not be an issue. If heat is not an issue the epoxy wont get damaged. As a result, the chances of survival is high. I forgot the name of the paint. But it is used to protect inside and out of gun barrels. I believe if not most but all people hear have not heard of it. Its paint that I just can not order myself and apply. It has to be ordered and applied by a certified person. I am seriously thinking about it. If it costs $10 per oz but if you have $1000 plus in the rocket plus motor and case a few hundred dollars for the paint job is well worth it. I know my other O motor rocket that I launched at Aifrest 20 I added up everything and I had over $4,000 in that rocket. So it is worth it

Here it the website of one of the products i am talking about.
https://www.cerakoteguncoatings.com/

Here is the data sheet. Just click on a color some colors are high temp rated than others.

https://www.cerakoteguncoatings.com/resource/downloads/

I am thinking of this color.
https://www.nicindustries.com/images/techsheets/C-242 Hidden White Product Data.pdf

The post cure should not damage the rocket unless you go over the glass transition of the epoxy. Majority of which are 180+, but a post cure below that should hold.

I will take a look at that coating. It is something to look into. Thanks for sharing.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

SinfulDarkLord said:

The post cure should not damage the rocket unless you go over the glass transition of the epoxy. Majority of which are 180+, but a post cure below that should hold.

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Most of the high temp paint you can easily obtain asks for post cure of 250 then 400 then 600...

Just because the paint can withstand the temperature doesn't mean the rocket underneath will survive. The paint or ceramic coating isn't actually insulating the structure from the heat.