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Correction: the article is from Dan Williams; only the comment at the end is mine. Dan is an outstanding amateur pyrotechnician and his (former) web page can be found with a search. There are other alternatives for rapid fire transfer; I'll post in the Research (Restricted) forum if there's interest.
Terry,

Thanks for the correction . . . I just fixed the post.

Please post in in Research Forum !

Dave F.
 
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Correction: the article is from Dan Williams; only the comment at the end is mine. Dan is an outstanding amateur pyrotechnician and his (former) web page can be found with a search. There are other alternatives for rapid fire transfer; I'll post in the Research (Restricted) forum if there's interest.

I'd be interested whenever I can get this stinking L2 flight done! Rocket and motor sitting here, just waiting...
 
Back to the scheduled program…

All the fins are tacked on
IMG_6311.jpeg

Fillets completed with thickened T88. Overkill, darn right but it’s what I had, what I’m used too, and, well, it’s my rocket

IMG_6314.jpeg

IMG_6318.jpeg

IMG_6319.jpegIMG_6320.jpeg

Each was formed with the old scientifically calibrated tongue depressor and touched up with a gloved finger and some alcohol.
 
Well you certainly won’t need those little paper fin joint reinforcement strips on the booster that are in the kit doing it that way!

I think those are put on the booster to keep the fins from breaking off on landing of the booster then to keep the fins on during boost; but those fillets are not going to break off :D
 
Well you certainly won’t need those little paper fin joint reinforcement strips on the booster that are in the kit doing it that way!
Another method . . . The Old-School "Interlap" Method ( wax paper, wrapped around an engine casing, inserted into position, prevents unwanted entry of Epoxy ).

Dave F.


INTERLAP.jpg825E139D-4C4A-4728-A0B0-422FAFB47A34.jpeg.jpg0883B0DE-DF9D-4CB6-B889-615A02096E86.jpeg.jpg
 
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I think those are put on the booster to keep the fins from breaking off on landing of the booster then to keep the fins on during boost; but those fillets are not going to break off :D
I expect so….but either way, the epoxy fillets will certainly serve the purpose. Those fins are pretty wide (almost Centuri or Fliskits style).

I’m extremely skeptical of the 3600 foot projected max altitude even F15 to F15 and even if built stock (and therefore light). But it’s probably not as far off as the claimed 1200 feet for the Blue Sapphire.
 
I expect so….but either way, the epoxy fillets will certainly serve the purpose. Those fins are pretty wide (almost Centuri or Fliskits style).

I’m extremely skeptical of the 3600 foot projected max altitude even F15 to F15 and even if built stock (and therefore light). But it’s probably not as far off as the claimed 1200 feet for the Blue Sapphire.
Maybe that 3600 ft is based on them flying at high altitude, in Colorado ?

Dave F.
 
I just jumped on this, bought two, because if one is good....
After all my experience with the Majestic, trying to lighten it up, I’m thinking epoxy takes this kit out of the range of a BP booster motor. Lots of alternatives, I’m off to visit the research thread, the Professor has my curiosity up.
 
You might be right, that's much lighter than my Majestic two stage.
Your finished weight will probably be over 6 oz., and with two E16's or two F15's....
Recalculating....
Two E16's = 5.8 oz.
Two F15's = 7.2 oz.
 
Is the kit complete at that point ( including recovery system ), needing only paint & decals ?

If so, adding an F15-0 and an F15-8 would add a total of 7 oz to the weight, at liftoff.

Dave F.

No, still needs recovery. Add an ounce or two there
 
Lighter and more aerodynamic than the majestic
I agree, my majestic flew pretty good on BP, on a calm day, and a 6’ rod. I ended up building it with a RRC-3 and air starting the sustainer. Lot’s more options for booster motors. I won’t talk about how many kits I went through to end up there.
They named that rocket right though, very majestic (slow) launches under the right conditions.

This thread has lots of potential for modifications, can’t wait to see what others might come up with.
Good luck with your build, and the first flight!
 
@Wayco

Agree, I see lots of potential in this kit, from rip-snorting single stage full send flights (could see 1/16” fiberglass fins there) to many two stage variants.

Happy to see that Estes added this to their line!
 
Maybe that 3600 ft is based on them flying at high altitude, in Colorado ?

Dave F.
Well, possibly.

My understanding is that in recent years those altitude estimates have come from Rocksim, but I have no idea what assumptions about surface finish (and launch site altitude) are used.

Since I fly an altimeter in just about everything I fly except saucer types I know that some recent releases don’t even come close to the claimed performace. I think it might be possible to get a Blue Sapphire up to 1200 feet - on a Q-Jet D16.

The Super Mars Snooper and the Super Orbital Transport don’t come close either. In the case of the latter, it’s fine, as the glider works really well and getting it back from twice as high as as the stack really goes on a D12 would be “interesting“, and seeing the whole flight easily is a good thing with that model.

With the So Long, it will likely be out of sight (but hopefully not out of site) even so. When I get one, it will have an Eggfinder in it when it’s flown F15 to F15, which I sincerely hope to be able to do.
 
Building the second one in much the same manner as the first. TBH, this kit is a very quick build.

One major difference is I am not going to use epoxy on the fins, only yellow glue and the paper reinforcement pieces. Curious to see what the weight difference will be, and if the savings can justify the reduced strength. Initial speculation is no, but will wait and see.
 
As stated built the second one without epoxy. Results:

The booster. Fins were tacked on with Tite Bond III then received an Tite Bond III fillet. After that came the paper strips that were adhered with “tacky glue.” That stuff has some uses and this was definitely one. Weight in the end, 32 grams.

IMG_6346.jpeg

IMG_6344.jpeg


IMG_6337.jpeg

Not sure you all are ready for this, please sit down and take a deep breath. The booster built with thickened epoxy:
IMG_6338.jpeg

Yup, one gram lighter.

Now for the bottom half of the sustainer:

Tite Bond III:

IMG_6342.jpeg

Epoxy:
IMG_6343.jpeg

Total delta, epoxy added 6 grams. Guess which one I’ll go with next time? Will give you all two guesses, but I think you will only need one.
 
Thank you for giving actual numbers, which certainly better inform my speculations. I'll stop assuming that epoxy is necessarily significantly heavier.
 
Well, possibly.

My understanding is that in recent years those altitude estimates have come from Rocksim, but I have no idea what assumptions about surface finish (and launch site altitude) are used.

Since I fly an altimeter in just about everything I fly except saucer types I know that some recent releases don’t even come close to the claimed performace. I think it might be possible to get a Blue Sapphire up to 1200 feet - on a Q-Jet D16.

The Super Mars Snooper and the Super Orbital Transport don’t come close either. In the case of the latter, it’s fine, as the glider works really well and getting it back from twice as high as as the stack really goes on a D12 would be “interesting“, and seeing the whole flight easily is a good thing with that model.

With the So Long, it will likely be out of sight (but hopefully not out of site) even so. When I get one, it will have an Eggfinder in it when it’s flown F15 to F15, which I sincerely hope to be able to do.

Rocksim always over calculates altitude until you back sim the CD with altimeter data. So will OpenRock but not as bad .

Also always use the manufacture's engine file not a rocksim made one.
 
Thank you for giving actual numbers, which certainly better inform my speculations. I'll stop assuming that epoxy is necessarily significantly heavier.

But is is compared to Gorilla Glue that I fly Mid Power Estes rockets on I205 with no fillets on their PSII plywood, just sealer to the body tube to keep air out of, the glue to the engine mount inside the tube.
 
Rocksim always over calculates altitude until you back sim the CD with altimeter data. So will OpenRock but not as bad .

Also always use the manufacture's engine file not a rocksim made one.
OR isn’t too bad as long as you get the actual weights in, which goes back to @Scott_650’s post, most of the time. Agreed about getting the right engine data. I just built an OR sim of the original K-25 Alpha using actual part weights and found that the OR altitudes were very much in line with actual data I have from flying FireFlys and FS Minis in Alphas, except for the C6 values, which are rather optimistic, especially when compared with Q-Jet C12 values. In my real-world flying, the C12 significantly outperforms the C6 in just about everything I’ve ever flown it in, often far more than you’d expect the extra 1.0 N-s would give. But the OR sim has them very close together here and in some other models for which I have lots of actual data. All of this really makes me suspicious of the C6 data in OR, even though it looks right.

But that’s a topic for another thread than this one….
 
Daniel the Rocket N00b, host of The Model Rocket Show podcast, did some research on the weight of adhesive and of paint - worth a look or two:

http://rocketn00b.blogspot.com/2018/05/glue-and-water-weight.html
http://rocketn00b.blogspot.com/2016/11/the-weight-of-paint.html
Some very interesting stuff here. I’m not entirely surprised by his results on the painting as I’ve kept a few notes while building and found similar things…that paint can easily at 25% more weight even in the LPR realm.
 
Thanks for the comparison between wood glue and epoxy. I've done a lot of research on bonding materials and what I've found wasn't surprising. In almost every instance epoxy was preferred even with the minor weight increase. I completely agree that epoxy isn't required in most applications but I do seem to be using it more and more now that I found T88 and can buy in larger sizes.

T88 is very simple to use and very versatile. As you demonstrated it can be thickened for fillets or thinned for coating fins, body tubes etc. I recently used it on a build where I warmed it and added a couple of drops of alcohol before using it to coat and entire rocket. Simply paint it on, hit it with a little heat and let it flow out to an even, smooth surface.
 
Rocksim always over calculates altitude until you back sim the CD with altimeter data. So will OpenRock but not as bad .

Also always use the manufacture's engine file not a rocksim made one.
I would say never trust manufacture's motor data. If you can't use real current data, at least use test data from an independent source, such as NAR S&T.
 
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