Anybody Have Altitudes for Estes Alpha?

Discussion in 'Low Power Rocketry (LPR)' started by Oscar G., Jan 6, 2020.

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  1. Jan 6, 2020 #1

    Oscar G.

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    Hey there everyone,
    I'm looking for an altitude chart of how high the estes alpha will fly (assuming no wind) On different estes motors.

    I'm trying to get as close to 240 ft as possible on an estes single use motor, and I have no idea which one to use.

    I know it's random, but here it is.

    Thanks!
     
    Last edited: Jan 7, 2020
  2. Jan 6, 2020 #2

    neil_w

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  3. Jan 7, 2020 #3

    BEC

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    Which Alpha? Regular Alpha (3/32 inch balsa fins, blow-molded plastic nose cone in the current version) or Alpha III (hollow injection molded nose cone, plastic fin unit).

    I have altimeter data on probably 75-90 flights between the two types (using mainly, but not exclusively PerfectFlite FireFly altimeters).

    For either one, getting to 240 feet on an A8-3 will be pushing it, but a B6 will take it well above that. Your best bet would be an Estes A8-5, or possibly a Q-Jet A3-4. In either case it will need to be a nice clean, straight build. If it's a regular Alpha, sanding the fins down to 1/16 thickness or airfoiling them will help significantly. For an Alpha III (or Alpha VI), just make sure the fins aren't bent.

    How will you be verifying the altitude?
     
  4. Jan 7, 2020 #4

    Matt_The_RocketMan

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    1/2 A6-2 should do something like 250-300 ft, depending on how much weight you make your rocket. (Bass wood vs Balsa) or maybe adding weight in the nosecone. If you have any questions on how to make these adjustments ask me, im very experienced with using [​IMG]
     
  5. Jan 7, 2020 #5

    Matt_The_RocketMan

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    He would most likely verify the altitude of the rocket using an Estes Alti-Tracker, or the Altimeter, i would perfer using the Altimeter.
     
  6. Jan 7, 2020 #6

    Oscar G.

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    I will be using a pnut altimeter, and it is a regular estes alpha. (3/32 inch balsa fins, blow-molded plastic nose cone)
    Would it be easier to try and get the weight down and fly on an A8-5 or add extra weight (like the altimeter / cosmetics) and fliyng on a B motor?
     
  7. Jan 7, 2020 #7

    BEC

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    Uh....how are you going to put a Pnut in an Alpha?

    A FireFly is a tight fit and forces you to fold the 'chute in thirds to get it all in. If you add a payload section then it's not strictly an Alpha any more. Then you'll probably want to go with a B and add drag (leave the fins square, for one thing) and mass.

    The only place to get weight out is to dump the big fat cylinder that serves as the motor centering ring and replace it with two smaller ones such as in many other BT-50-based models. Thinning/airfoiling the fins will help much more.
     
  8. Jan 8, 2020 #8

    Oscar G.

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    HA! my bad! Using a pnut in my Junior L1, using a jolly logic altimeter three in the alpha.
     
  9. Jan 8, 2020 #9

    neil_w

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    Alt3 will significantly increase the weight of the Alpha, to roughly the weight of the Alpha 3. So the table I referenced earlier at the Apogee website should be at least in the ballpark. I can't say if it'll fit in there so well with the chute though.
     
  10. Jan 8, 2020 #10

    BEC

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    AltimeterThree won't fit either. Here is AltimeterThree in a clear-bodied Alpha I built for some education programs. There is minimal wadding and the 'chute is folded in thirds. As you can see the nose cone won't go on. IMG_2343.jpg

    Here is the A3 outside with the nose cone on. The left end is at the top of the packed 'chute.

    IMG_2344.jpg

    Next are a FireFly and a FlightSketch Mini in the same space. I wouldn't recommend flying them bare like this. They need to be protected from ejection gases (your Pnut would have needed it as well).


    IMG_2346.jpg IMG_2347.jpg
    As Neil noted, the A3 is a significant mass in this model as well.

    Oddly the heavier Alpha III flies as high as a regular Alpha (rounded edged fins, not airfoiled) when carrying the same altimeter. It's gotta be those much-thinner fins.

    A FireFly or FS Mini (or MicroPeak) go in the Alpha III nose cone even when wrapped for protection. A first generation AltimeterOne/Two would also fit in there, but the current ones and AltimeterThree won't.
     
  11. Jan 8, 2020 #11

    Oscar G.

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    Damn. I will find a solution somehow . . . Would extending the body tube work? I could add a coupler and slap a couple of extra inches of tubing on there?

    Brain work in progress
     
  12. Jan 8, 2020 #12

    ebruce1361

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    Extending the body would allow for the space to put the altimeter, but would add even more weight. If I were doing this, I would cut off the base of the nose cone and stuff the altimeter into the nose with some tissue paper or wadding and a piece of masking tape to hold it in place with an additional tether to attach it to the shock cord as a backup in case the tape breaks. As for the nose itself, you can try to cut around the existing shock cord loop so you can still use it, or put a small blob of epoxy (the longer cure time, the better; shorter cure times will create heat that can warp the nose) down in the tip and anchor the shock cord in the epoxy.
     
  13. Jan 8, 2020 #13

    BEC

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    Extending the body tube will work....but if you're going to do that you might as well make a proper payload section out of it. However, that is more weight and more surface area and so more drag. Still, if you use B motors you'll have PLENTY of excess performance.

    embruce's idea of opening up the bottom of the nose cone and stuffing the altimeter in there (or part way) as I was suggesting is possible with the Alpha III and a FireFly or FS Mini or MicroPeak might get the A3 in a stock-length Alpha, if you get creative with attaching the recovery system to it.
     
  14. Jan 8, 2020 #14

    mikec

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    You could use a more compact recovery system, like a streamer or a thin-mil nylon or mylar chute.

    You could always go old-school and measure the altitude with visual tracking.
     
  15. Jan 9, 2020 #15

    BABAR

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    Use a C6-5 and attach 240 feet of Kevlar thread to the rocket, the other end attached to a cinder block
     
  16. Jan 9, 2020 #16

    BEC

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    :D

    (A B6-4 will do, though :) )
     
  17. Jan 9, 2020 #17

    ebruce1361

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    Go big or go home. load that puppy with a Quest D16-8 Q-jet and pray your kevlar holds.
     
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  18. Jan 9, 2020 #18

    Homer_S

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    I was thinking modify the nose cone to allow the altimeter to be in that space. Shouldn't be too hard to remove the bottom and do the drill a hole/insert a dowel/epoxy/sand smooth thing to make a good anchor point in the nose.

    Homer
     
  19. Jan 10, 2020 #19

    Oscar G.

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    "They say great minds think alike, but in truth, great minds think of things nobody else would ever consider"
    - Unknown

    BABAR: as much as I love this idea, 240 feet of cord is expensive, and I don't think that's legal in the friendly competition I will be flying in. I plan to pursue this idea on a different, more expendable rocket, and will most certainly post photos of the experiment when I do.

    Homer_S / BEC: I will probably put part of the altimeter in the nose cone partway, and then make a little pod around the bottom of it that I can seal on with duct tape and slide into the payload section. this will act as the new nose cone, and then the shock cord will attach to the bottom of the pod, with a backup running to an anchor point in the nose cone.

    I honestly don't think I can refer to this monstrosity as an estes alpha anymore, but as I name all of my rockets, I would love your input as to what I should call it.

    Photos to follow on Saturday or Sunday (probably)
     
  20. Jan 10, 2020 #20

    BABAR

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    300 yards, 50 lbs strength, about $10 plus shipping.

    https://www.thethreadexchange.com/miva/merchant.mvc?Screen=PROD&Product_Code=KEV160NATL02sp

    Now regarding LEGAl, you didn’t mention any rules;)

    Made me think about the TARC challenge
    https://rocketcontest.org/wp-conten...les-TARC-2020-Final-as-of-18-May-2019.doc.pdf
    Target altitude is 800 feet. I didn’t see anything in the rules that would DISQUALIFY someone for having a tether to the ground (although I am guessing it would be frowned upon!). You’d need some elastic, a hen’s egg isn’t going to take kindly to snapping to a sudden halt when it reaches the end of the Kevlar.:angiefavorite:
     
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  21. Jan 11, 2020 #21

    Oscar G.

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    HMMM.
    Im meeting with my TARC team today, and I will see what they think of the idea. probably not going to happen, but I love the concept. funny that nobody thought to put somthing like that in the tarc rulebook =)
     
  22. Jan 11, 2020 #22

    Nytrunner

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    Yeah....Trip Barber would not be impressed
     
  23. Jan 11, 2020 #23

    BABAR

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    Hmmmm.... a “Trip-ping” point (pun intended) is that the duration is based on the time until first part of the rocket touches down. Judge could very well say that if the line is attached to the ground at launch and never departs the ground that your time for the event would be 40 minus zero, which would be a big penalty. So you are going to have to have either a chute or streamer that LEAVES the ground, activates your deployment sequence at the 800 foot altitude, and gets retracted or otherwise lifted into the air, and does not touch the ground for the 40 seconds. Starts to get a little Rube Goldberg-ish. Still fun to think about.

    Taking advantage of the loopholes in the rules,

    streamer on the ground, 780 feet of cord, only the first 5 or 10 feet need to be flame proof. Rest is just strong enough not to break when rocket hits 780 feet.

    Single stage rocket, with “Dart” configuration (unpowered Upper section, which can contain nearly the entire rocket, including the fins and motor casing, but does NOT contain the altimeter, which is in a pod that gets released by a trip device when the 800 foot tether length is reached. Maybe put a chute or more likely a streamer on this, so when deployed, it basically goes maybe 20 feet to get to 800 feet.

    Two sections attached by another elastic shock cord plus say 100 feet of Kevlar thread, long enough to allow a safe deceleration of the egg payload compartment (which is now dragging the streamer), strong enough to support the weight off the altimeter pod, 780 feet of cord, and streamer and streamer drag.

    Launch rocket.

    At 780 feet the string, still attached to the Dart, trips something that separates the motor AND altimeter pod. This segment is unstable (or has a VERY strong shroud line chute) and almost immediately stops. This is your altimeter reading. Yes, the rest of the rocket is still ascending, in reality the apogee maybe 850 to 900 feet depending on length of “daisy chained” shock cord, but you are scored on the ALTIMETER reading. So if you can figure a way to deploy your altimeter at 800 feet AND keep it attached to the rest of the rocket, you have hopefully nailed altitude assuming a vertical rocket launch.

    Okay, so we have deployed the altimeter pod at 780 feet, assume inertia combined with chute or streamer gets you to 800 feet.

    I attached the ground streamer to the Dart. Why? Because if HAVE TO GET THE STREAMER OFF THE GROUND AND UP INTO THE AIR, otherwise if it it never leaves the ground it counts as the first part of the airframe to touch down, so time is zero. Dart keeps going up, slowing but taking the streamer up off the ground with it, I am hoping to get another 50 -100 feet, as I think a thick streamer with NO Weight attached will likely take about 30 seconds or more to drift to the ground (remember, START time is when rocket starts its first motion, NOT when last part leaves the ground. So the LATER it leaves the ground, and the longer it floats, the less likely the streamer or string is going to be the first touch down part.)

    (Another loophole in the rules about first part to touch the GROUND or TREE, put the STREAMER AND STRING on the side of PAD. This doesn’t count as the “ground” or a “tree.” You still need to get it into the air, otherwise your dangling string will be the first part of the rocket to touch the ground. But the judge CAN’T legitimately say that it was touching down from the moment of launch and give you a 40-zero penalty.)

    Okay, now for the DOWN part (timing). Your altimeter pod section Also deploys a parachute with a weight and a string say 400 feet long (I am thinking the main body of the rocket is gonna deploy pretty soon and start descending so you won’t need 800 feet.). This can be a very lightweight string.
    You can predict to about 1 second the time from launch to deployment, and within say 40 feet of the altitude. Using experience you should be able to come pretty close to appropriately sizing your parachute to hit your target impact time. The beauty of it is you can use a larger chute for your payload for a gentler landing of your egg, since it can land many seconds later.

    In an attempt to “un-hijack” your thread, Oscar, we need more information on your rules, which sound much less restrictive than TARC. If the rules are, who can get closest to 240 foot reading on an Alpha with an onboard altimeter, I am thinking if you build the altimeter into a side pod released by a 240 foot string (and attached with an eyelet hook so it slides down the string) and there are no rules regarding attaching the string to the ground, it could be done safely.

    YAMV (Your Altitude May Vary.)
     
  24. Jan 13, 2020 #24

    ebruce1361

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    A LITTLE Rube Goldberg-ish?!?! This sounds like the kind of over-engineered tomfoolery that might just short-circuit Murphy's law and work! I might have to build one for the fun of it.
     
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  25. Jan 13, 2020 #25

    BABAR

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    Time for @Daddyisabar to join the fray....I mean discourse .

    His tapeworm was a tractor type rocket. With the point of tail attachment definitely BEHIND the CG (and the motors) this might from a physics standpoint decrease probability of a St. Louis arch.
     
  26. Jan 13, 2020 #26

    kyle

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    For hitting your altitude, you might try an A10 in a motor adapter. Alpha on an A10 is what I used to use as a first launch rocket to get an idea of the winds. Unfortunately I never actually measured the altitude, but it did go higher than an A8.
     
  27. Jan 14, 2020 at 2:53 AM #27

    Oscar G.

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    Just want to take a moment to thank everyone here!
    I finished the build yesterday, and open rocketed the heck out of it. it should now hit exactly 240 feet on an A-8, and It also has a really cool paint job. (photo to follow when I feel like it). I will be bringing it to the LUNAR snow ranch launch on feb 1st along with (possibly) the first draft of my junior L1 rocket. (find me with the gunn high school TARC team).
    This was not only a really cool project, but it was also my first thread on the rocketry forum. I discovered the website when I was one week into the project, and I was overwhelmed by the vast trove of knowlege availible here in the forum, as well as how friendly and willing to help people are. I loved working with you all, and am super thankfull for all the advice I was given.

    -Oscar G.
     
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  28. Jan 15, 2020 at 4:52 AM #28

    BABAR

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    Best wishes for a great flight!
     
  29. Jan 18, 2020 at 5:34 PM #29

    Oscar G.

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    upload_2020-1-18_9-3-11.png webcam-toy-photo-20200118170023.jpg

    Some photos of the completed rocket!

    I decided to name it the rat on a stick, it's hard to see the letters in the photo, because they are backwards, but the skwered rat decal I made is partly visible. The final version ended up with an extended body tube to fit a jolly logic altimeter three, and a sketchy tape coupler, reinforced with epoxy. Getting ready to do first launch With SARC on the 25th, so I will post the data then, but as far as openrocket says, it should hit extactly 240 feet.

    - Oscar G.
     
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  30. Jan 19, 2020 at 6:03 AM #30

    BABAR

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    “rat on a stick” is certainly a better name than “Vlad the Impaler”!
     

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