MADCOW 4" FRENZY CARDBOARD ROCKET... A BUILD THREAD #1

Just give mike a call at MC and I am sure he would send you a new fin.

crossfire said:

Just give mike a call at MC and I am sure he would send you a new fin.

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I'm sure he will. Before I do that, I want to exhaust all methods of straightening, first. Straightening this fin has now become a 'mission' and there are a lot of good lessons/educational rewards to be gained in trying to straighten this thing out. I'll either 'win' and get it straight, or I will turn it into a 'guinea pig' for further tinkering... and 'then' call Mike!

38mm loki talk , I316 spitfire would do a good show if your field allows sparks at launch , my loaded 93.6 oz sim motor deploy shows 2297 feet , rail speed is plenty

Delay though would need trimmed to around 9/10 sec from 17 sec

michigander said:

38mm loki talk , I316 spitfire would do a good show if your field allows sparks at launch , my loaded 93.6 oz sim motor deploy shows 2297 feet , rail speed is plenty

Delay though would need trimmed to around 9/10 sec from 17 sec

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I'm learning how to use OpenRocket and do the flight sims. Delay times are not a biggie right now. I'll be using altimeters and DIY deployment charges. Being a newcomer, I'm liking Loki. I'm liking them a lot! Via OpenRocket sims, I was having trouble matching any of Loki's systems to my initial low/slow 54mm desires. Loki offers no adaptors for 54mm to 38mm. That's okay. I'll simply buy 'two' motor cases. One of them will be 54mm, the 'other' will be 38mm. Best of both worlds after I purchase my next rocket for 38mm (probably tonight). When I show up for my cert flight, I should easily find both motor sizes sold by vendors, be they Loki, or whoever. I'll be able to shove a load of propellent into either, or both rockets, no matter what. I'm not wanting to put all of my eggs into one basket, on motor selection. I'm simply new to this. I've no choice but to start somewhere and grow from that point. Loki is where I start...

https://www.madcowrocketry.com/aero-pack-38-to-54-adapter-a3854/

there is some adapter reading material

TMJ said:

Loki offers no adaptors for 54mm to 38mm.

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As far as I know, Loki motors work in Aeropack's adapters just like any other brand. Apart from an odd set of 54mm->38mm closures that Aerotech made over a decade ago, I'm not aware of any motor manufacturer making adapters.

Madcow Super DX3 is on the way! I left a message, for Mike, to discuss a few other things. Waiting for the call back...

eggplant said:

As far as I know, Loki motors work in Aeropack's adapters just like any other brand.

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I think he means to fly a 38 reload in a 54 case...... And no one adapts like that.... any 38-54 adaptors you see are to load a 38mm case into a 54mm motor mount.

To put this in perspective.... most people have MANY cases. I'd say average is between 3 to 50 cases.

DavidMcCann said:

I think he means to fly a 38 reload in a 54 case...... And no one adapts like that.... any 38-54 adaptors you see are to load a 38mm case into a 54mm motor mount.

To put this in perspective.... most people have MANY cases. I'd say average is between 3 to 50 cases.

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Yep, 'you' nailed it, David!

Fin still warped, but I 'think' I've got it figured out. I'll know for sure, tomorrow evening. If plan "Z" actually works, as hoped, I'll repeat the process on a few new pieces of intentionally warped plywood, of various thicknesses, in order to truly test my methods, theories behind those methods, and the probability of successful results. If it works, in a predictable manner, using different thicknesses of plywood... I'll post the process, the reasons 'why' I did what I did and the final results. This isn't so much a 'rocketry' thing as it is a material science thing. I hope it all works. I'd like to share something beneficial to the community rather than just asking questions!

In the 'mean time'... I've purchased the Super DX3. I've also asked Mike to include a new Frenzy fin, just in case I am wrong about my warped plywood experiment(s).

TMJ said:

Fin still warped, but I 'think' I've got it figured out. I'll know for sure, tomorrow evening. If plan "Z" actually works, as hoped, I'll repeat the process on a few new pieces of intentionally warped plywood, of various thicknesses, in order to truly test my methods, theories behind those methods, and the probability of successful results. If it works, in a predictable manner, using different thicknesses of plywood... I'll post the process, the reasons 'why' I did what I did and the final results. This isn't so much a 'rocketry' thing as it is a material science thing. I hope it all works. I'd like to share something beneficial to the community rather than just asking questions!

In the 'mean time'... I've purchased the Super DX3. I've also asked Mike to include a new Frenzy fin, just in case I am wrong about my warped plywood experiment(s).

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+1 on buying another kit while asking for a part for a previously purchased one. Have been done that road myself.

OTOH, it usually costs me money when I talk to Mike. LOL!

The Super DX3 is a nice bird.

o1d_dude said:

+1 on buying another kit while asking for a part for a previously purchased one. Have been done that road myself.

OTOH, it usually costs me money when I talk to Mike. LOL!

The Super DX3 is a nice bird.

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FWIW... I don't have to call Mike. Seems as though all I truly need, in order to spend money, right now, is to simply boot up my 'puter! :lol:

Offensive warped fin now 'not' so offensive! It looks a bit off, via my photo, but with a straight-edge laid across the fin it shows to be as straight as a laser beam! I just need to once again touch the leading edge, with a piece of sandpaper, since straightening... but so far, so good. Now comes the test of time. I want to let this thing cure for a couple/three days to insure that it will hold its flat shape and not warp again without being weighted down. I'm keeping my fingers crossed!

Straightened fin is now loosely inserted into slots in booster section (the fin on the right of photo). No glue, just a static fit. I'll let it stabilize, in place, to see how it 'shapes' up after a couple of days...

Just received some 60" Aerocon parachutes. "Thanks, AfterBurners!" I'm amazed at the quality of these things. The price point is definitely 'unbeatable'! "Simply AMAZING!"

Perhaps I should 're-phrase' that... but nahhh. You know what I mean. Let's see what rolls in on 'this' one... :surprised:

at the risk of sunburn or mosquito bites no. the rocket on the other hand doesn't (usually) have to worry about those problems. although I would suggest primer at a minimum.
Rex

It's fairly common. I do it when the weather just isn't good for painting but something needs to be flown

Warped fin is now straight and holding its shape well.



All fins are now attached!



The airframe was sucked in/concave along the fin slots. Something about 'that' that I do not like, aerodynamically. Need to straighten out the airframe/airflow along this area. Wanting a straight/clean line!



Problem solved. I now have a smooth, straight, aerodynamically clean airframe all along the booster



I still have a small bit of work to perform inside the body, before securing the aft CR into place. I'll let things cure, overnight, before removing the aft CR to finish things up inside.

I wasn't too happy with the 1/2" dia. hardware backing for the upper rail button. Not a lot of support/structural integrity in such a small footprint of surface area upon a cardboard tube. I've added a two ply fiberglass layer, inside the body tube, to spread out the load/stress of the rail button over a greater surface area. I feel much better with 'this'!

I was finding it quite difficult to reach way up the tail end to apply epoxy fillets to the fins (old eyes and unsteady hands) so I decided to 'pin' the fins in place for added security. Don't want to risk them getting ripped off during launch, or banged off via an unintentional hard landing. Pin profiles will give me a larger target to hit with an epoxy stick while adding a bit more insurance to boot. I didn't need to pin the aft fins, as they are close enough for me to fillet, but what the heck. Might as well be consistent and pin them all.

You did what now?

Well that certainly is a new technique.

I understand wanting extra strength, especially in case of landing and ground mishaps, but in terms of standing up to flight forces do not underestimate the strength of a simple root glue job. Heck even without fillets they are strong enough for most of the flights I watch in this range.

Flyfalcons said:

You did what now?

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In general aviation, folks typically 'Remove Pins Before Flight'. "I'm doing the opposite!"

syringe and tubing works great for depth , FG cloth strips would also work great mixed in the internals , or even add some chopped fiber if you still have strength concerns

michigander said:

syringe and tubing works great for depth , FG cloth strips would also work great mixed in the internals , or even add some chopped fiber if you still have strength concerns

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I actually intended to use FG cloth, strategically, inside the airframe, however. I was having such a difficult time just getting the epoxy where I wanted it... I nixed the FG thing. No way that I'd have been able to properly locate, or saturate the cloth pieces. I like your syringe/tubing thing. I initially tried to tape drinking draws together and draw the epoxy into the straw, then blow it out. It worked, kinda, but not well enough. That's when I came up with the 'pin' idea. With pins I do not need to be accurate, nor fancy. All I needed to do was mark the depth of where I wanted to be, on a flat stick, with some tape, then shove a glob of epoxy up the rocket's arse and rub the stick back and forth along the pins. The pins grabbed the epoxy and gravity did the rest in sending the epoxy 'exactly' to where I wanted it to go! "Worked like a charm!!!" :wink:

Pins worked 'GREAT'! Aft CR is now installed and curing. Next, I'll need to trim the tag ends of my pins and sand everything flush with the body tube. There will be no need for thick fillets along the fins. All of the strength is on the 'inside' of my airframe. All I'll need to do to the outside is add very, very small fillets along the fins (Titebond III) for smooth streamlining.

TMJ said:

Just received some 60" Aerocon parachutes. "Thanks, AfterBurners!" I'm amazed at the quality of these things. The price point is definitely 'unbeatable'! "Simply AMAZING!"

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Fantastic I'm sure you will be pleased with their performance The build is coming along nicely so far. Keep up the good work and take your time.

watermelonman said:

Well that certainly is a new technique.

I understand wanting extra strength, especially in case of landing and ground mishaps, but in terms of standing up to flight forces do not underestimate the strength of a simple root glue job. Heck even without fillets they are strong enough for most of the flights I watch in this range.

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I don't doubt what you say, however. It's the 'most flights' part of your response that makes me less than 100% sure of simple root joints. I've read a lot of stories about fins coming off. I don't know how those fins were truly mounted, if it was due to poor building, inferior adhesives, or what. I'm just trying to insure that "I" won't be having to detail one of those failures on this forum. It's a confidence thing, for me.

I'm now plugging the blind nuts/threads of my motor retention hardware with beeswax. "Why am I doing this?" Two reasons. Reason #1... Epoxy won't stick to beeswax. Reason #2... a thin epoxy coating on the bottom of the rocket will make for easy post flight clean-up. "Don't want my rockets to come home with dirty butts!"