Estes Super Alpha

DITCH the 18mm mount on this rocket and on ANY rocket BT-60 or larger in diameter and go with 24mm. One can ALWAYS fly with an adapter down from 24mm to 18mm, but one cannot get any more power than an Aerotech D24 in an 18mm case.:bangbang::gavel:

ghrocketman said:

DITCH the 18mm mount on this rocket and on ANY rocket BT-60 or larger in diameter and go with 24mm. One can ALWAYS fly with an adapter down from 24mm to 18mm, but one cannot get any more power than an Aerotech D24 in an 18mm case.:bangbang::gavel:

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I'm of largely the same opinion. I looked at most of the recent Estes releases and was taken back a little by how many of them were 18mm equipped. No doubt Estes tends to power-limit some of their designs to avoid complaints from irate dads after their testosterone gets the better of their tracking skills But lots of these birds are begging for the Impala SS treatment Pull that V6 outta there and drop in the V8!

Seriously, rockets like the Big Bertha are well suited for D12's and E9's - under the right conditions of wind, field size, visibility, etc. Of the new releases, the Cosmic Explorer, the Reflector, the Super Neon, the Satellite Interceptor and the Photon Disruptor all look like good candidates for 24mm power. I'm not talking G55's but Estes D's and, in some cases, E's, are not over the top.


Doug

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I think the reason for the 18mm in so many birds is a motor cost issue.

Most general merchandisers (Michael's, Wal*Mart, etc.) will carry the A-B-C motors but it seems like only the rocketry-oriented LHS carries the 24mm motors. I was able to buy motors from Wal*Mart for $5.97 list but the LHS charges me $10 for the 24mm C-D motors and $15 for the E-9s.

We rocketeers will pay what it costs to fly either by way of the LHS or mailorder motors but the mass market appeal requires a more affordable pricing on motors and greater availability.

My Super Alpha (at least the first one) has the stock 18mm motor mount. If I'm flying it where a D would reasonable, I'll put an Aerotech D10 in it. I managed to get it primed and the base coat of white on it over the weekend. First flight should be this coming Saturday.

gpoehlein said:

Hey - it looks just like an Alpha! :neener:

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Well, to be picky... (and I'm picky about Alphas)

The body tube is an inch shorter than it should be. But that is somewhat corrected by a slightly longer nose cone (I think it is about 5/8" longer than it should be. And the nose cone is more of a secant ogive than a tangent ogive.

So, similar to how I worked around the short nose cone of my MegaAlpha, by making the tube longer and painting the nose cone's color down a bit, I'm going to paint my Super Alpha with a red nose cone, but the bottom, oh, 7/8ths of an inch will be white to match the body tube.

Well..... if'n you're that picky...have you checked the fin shape to see if it's the original shape, the more recent one (Alpha III type which is also on current balsa-finned Alphas) the Maxi Alpha III shape or its own variation?

I'm genuinely curious....I just haven't done the measurements and calculations to figure it out for myself.

No progress today - odd day at work and raining again. I hope to at least get it masked for the second color tonight before I keel over.

BEC said:

Well..... if'n you're that picky...have you checked the fin shape to see if it's the original shape, the more recent one (Alpha III type which is also on current balsa-finned Alphas) the Maxi Alpha III shape or its own variation?

I'm genuinely curious....I just haven't done the measurements and calculations to figure it out for myself.

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The fins are pretty much spot-on. They're a little thin, but I'm laminating them with label material which should bring them closer to .156" thick.

I just joined the club as well.

Evo666 said:

I just joined the club as well.

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Welcome!

Wish I could get mine painted, but way to humid right now.

What motors are you guys using for the 24mm motor mount? I'm also guessing you guys are ditching the weak parachute too?

BEC said:

...have you checked the fin shape to see if it's the original shape, the more recent one (Alpha III type which is also on current balsa-finned Alphas) the Maxi Alpha III shape or its own variation?

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I know the "Maxi" was bigger, but was there really any significant variation in the fin planform shape? (sweep? taper ratio? aspect ratio?)

I guess I just glanced at all the Alpha versions over the years, eyeballed the fins and assessed them as being the same shape, and never looked closer. I mean, I wouldn't be surprised to hear that there were minor manufacturing differences (each time they set up a new production run they could have easily introduced a tiny change in dimensions). But are the fins really that much different?

You got me curious now...enquiring minds want to know....

Rather than my recreating hit here, take a look at this thread on YORF: Alpha Fins

I haven't done measurements on my Maxi Alpha III to compare the actual variations in sweep and aspect ratio, but they visually do look different. One of the things I plan to do before flying the Super Alpha is get a group shot of Alphas I-IV along with the Maxi III and the Super.

Evo666 said:

What motors are you guys using for the 24mm motor mount? I'm also guessing you guys are ditching the weak parachute too?

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...and the rubber strip shock cord, as well.

As to motors, I was thinking about taking the conservative approach with perhaps a C11-3 and then a D-12-5.

My plan during construction is to weigh the various assemblies so I can sim the build in OpenRocket. Then I'll be able to figure out how much ballast to add to the pointy end when it's time for the E18... :y:

ghrocketman said:

DITCH the 18mm mount on this rocket and on ANY rocket BT-60 or larger in diameter and go with 24mm. One can ALWAYS fly with an adapter down from 24mm to 18mm, but one cannot get any more power than an Aerotech D24 in an 18mm case.:bangbang::gavel:

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I can understand why some people like to use bigger motors to launch rockets higher and higher, but when you add bigger motors in the rear end you are also adding weight.

I think everybody understands that a bigger motor installed in the aft end means that the overall c.g. shifts further aft. At best, this reduces the stability margin. Worst case, this could shift the c.g. until the rocket is unstable.

I think everybody understands that to fix this, you have to add some nose ballast. You need enough ballast so the overall c.g. (with the heavier motor) is back where it started.

So now you have the original rocket, plus more motor power, plus more motor weight, plus ballast weight. I have to wonder how much more altitude you actually get out of the increased impulse.

I like using 18mm motor mounts because it's too darn windy around here most of the time to launch anything to 1000 feet and have any chance of getting it back. I really like that 18mm motors are available in A, B, C, and even D impulse classes, giving me a wide range of choices in altitudes.

I'm glad (and a little envious) that some folks have big enough launch areas to be able to use bigger motors, but I'll be sticking to the original MMT.

BEC said:

Rather than my recreating hit here, take a look at this thread on YORF: Alpha Fins

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BEC,

You have a very nice collection of some very nicely built Alphas, along with some great photos posted over on YORF.

Unfortunately, my old eyeballs cannot detect the dimensional differences you were referring to. (I'm not saying they aren't there or that you fibbed or anything like that, just that I can't see them in the pictures.)

Any chance that you could make a few measurements and post some numerical values?

I've got some numbers, but I'll have to dig 'em out. Look at the fins comparison shot at the end of that thread. It shows current Estes laser cut Alpha fins beside Semroc K-25 fins (which match the original shape) both side by side and stacked on top of one another. The newer shaped ones have a a bit more span and less chord at the tip. Here's a direct link to that picture.

The C-grain fins with the little hole at the root are the current Estes ones. That shape, BTW, matches the Alpha III/IV plastic fin shape.

powderburner said:

I know the "Maxi" was bigger, but was there really any significant variation in the fin planform shape? (sweep? taper ratio? aspect ratio?)

I guess I just glanced at all the Alpha versions over the years, eyeballed the fins and assessed them as being the same shape, and never looked closer. I mean, I wouldn't be surprised to hear that there were minor manufacturing differences (each time they set up a new production run they could have easily introduced a tiny change in dimensions). But are the fins really that much different?

You got me curious now...enquiring minds want to know....

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The Maxi Alpha 3 fins are about 3/4ths the size they should be if they were going to be scale. The root edge would be 2.25 * 2.69 = just over six inches vs. 4.6" for the Maxi. The tip would be about 3.4" versus 2.5 on the Maxi, and the sweep is a few degrees less than the normal Alpha fins.

I should add that they probably did this to reduce costs, and because big plastic fins would be more likely to break on landing (and the Maxi Alpha 3's fins are easily breakable!). And then there was the Maxi-Brute Alpha which probably had the same size balsa fins, probably for pretty much the same reasons (reduce costs and potential breakage). Here is an example of a Maxi Alpha fin

I can tell you that the Maxi Alpha (not III) has slightly different fins - I think they are a bit smaller. I did a comparison quite a while back and did note a difference between the Maxi Alpha fin pattern and the scaled up Alpha fin pattern. At this point I could not tell you what the differences are.

Here are a couple of shots of a bunch of Alphas including my just-completed SuperAlpha.

The standard-sized ones are, from left to right:

Alpha from a recent Estes bulk pack - laser cut fins, blow-molded plastic nose cone
Alpha II clone from Semroc parts including BNC-50K and laser cut K-25 fins
Alpha III (with body tube replaced with a length of ST-9 - see the AltimeterOne thread for the whys of that)
Alpha IV

The two taller ones are self-labeled enough.

In these views the Super Alpha's shorter than strictly scaled up body length really shows.

You need a BT-5 downscale in there too Bernard. Check out this thread from the archive:

https://www.rocketryforumarchive.co...8&highlight=downscale+of+some+classics&page=2

Posts 36 and 37 give PDF files for printing out BT wraps and fin wraps. Just print on 32# presentation paper, glue to a BT-5 and paint the nose cone! (Uses the nose cone from a 220 Swift.)

Hey when are we going to see the finished product?

TA

Don't know about you but I've taken a hiatus from building Colorado-based model rockets.

thobin said:

Hey when are we going to see the finished product?

TA

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I'm waiting on the humidity to drop so I can spray. After today it seems like along way off.

o1d_dude said:

Don't know about you but I've taken a hiatus from building Colorado-based model rockets.

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Indeed. The "family grouping" I posted last night was taken just before I read Carl's opening post (on YORF), then found it here as well.

So I'm planning to buy more motors than I would've when Quest starts their sale tomorrow and order a few motors from ValueRockets.com - and I need to figure out what more to order from Carl. Maybe I need more Semroc designs than the My Boid and Vega I have in my fleet already.

Tomorrow I start building my Semroc Trident xKit.....

I emailed Nettie over at Quest today and told her they better have a large stock of motors laid in and to expect a somewhat higher than normal demand for them.

I've always liked the Big Betty.

o1d_dude said:

Don't know about you but I've taken a hiatus from building Colorado-based model rockets.

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Don't forget - Quest is in Colorado, too.

Trident said:

Don't forget - Quest is in Colorado, too.

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Good point. So is Apogee.

BEC said:

Here are a couple of shots of a bunch of Alphas including my just-completed SuperAlpha.

The standard-sized ones are, from left to right:

Alpha from a recent Estes bulk pack - laser cut fins, blow-molded plastic nose cone
Alpha II clone from Semroc parts including BNC-50K and laser cut K-25 fins
Alpha III (with body tube replaced with a length of ST-9 - see the AltimeterOne thread for the whys of that)
Alpha IV

The two taller ones are self-labeled enough.

In these views the Super Alpha's shorter than strictly scaled up body length really shows.

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Nice family shot!

Boosterdude said:

Nice family shot!

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Thanks. The Super flew once last Saturday. It was a bit breezy (winds variable 6-8, gusting to 12 mph) and blowing pretty much across the short dimension of our small field so it was angled well into the wind. So on a B6-4 the delay was a bit long for the arcing trajectory. The 'chute deployed well and it landed on field and with no damage. It WILL be flown more - probably starting at the OPROC "Pasture Blaster" near the end of the month. There I will have room to fly it on as much power as I can get in it (Aerotech 18mm Ds).

I'll throw my Super Alpha in. The paint is dry and it's ready to fly.