Yogi's builds - to boldy glue, where ...

[Retired_for_now]

Was looking for something unique for the Fiddler's Green workup - not too many helos and this one is significant in this area (Hurlburt Field).

The Sikorsky YR-4 was the first operationally deployed US helicopter - notably used during WWII in India/Burma by the 1st Air Commando Group (Project 9) for medivac and rescue of downed aviators. Six prototypes were delivered, two were lost during operations. The 1ACG was one of the forerunners of todays USAF Special Operations aviation (red-headed stepchild of the bomber/fighter dominated Air Force). Likely drop this off along with a CV-22 model to my local USAF historian buddy.



If you give this one a try, use the 3-view drawing for correct rotor installation. Picture above has the rotor backward (shot before research complete). Fortunately, the rotor is not glued or locked down so a quick flip puts things to right.

Yogi

[mbauer]

Hi Yogi,

Just on page two. But after your intro and knowing what you're doing with the schools, would you mind if I stop by the Challenger Center here in Kenai, Alaska and share some photos and the link to this thread?

I'm sure with all of the kids they bring through that the launchers and rockets would be much appreciated!

Just finished a couple of weeks intensive design/build and finally getting around to reading some of your posts!

Thank you for sharing them!

Insanity like this is no problem! The photos, story and description comments are great!

Mike Bauer

[mbauer]

Originally Posted by Wyvern

I like the one in the middle.

Wyvern

Hi Wyvern,

Me too!

Mike

[Retired_for_now]

Mike,
Pass on the info to any schools or organizations you like. After all, that's my reason (excuse?) for all the time spent fiddlin'. I'm currently cranking out little F-35 gliders (aviation downloads here) to use as "bait" during an Air Force Association membership drive - the small humans drag the big ones right on over.

The Lower Hudson Valley Challenger Center < The Lower Hudson Valley Paper Model E-Gift Shop > is also a link Kenai Challenger Center should have. And, if you give them a link to Canon < Paper Craft - Canon CREATIVE PARK > there's a polar bear, orca, and eagle (among many other animals); < Free Paper Toys, Paper Models and Paper Crafts at ss42.com > also has a lot of useful links - use the menu on the left.

Just remember - they'll have to register on the forum to view the pictures (I think we'd all be honored to have someone from the Kenai Challenger Center join us - give Jon some company as well).

Yogi

[mbauer]

Hi Yogi,

Thanks for the permission. Jon's site will be the big selling point, as well as this site too.

I got the feeling that your models will be much admired!!

More than happy to help promote our hobby/obsession!

Mike

[Retired_for_now]

So, you've heard about the months-long night during the Alaskan winter. And, the long, long summer days. And sometimes, you forget that it's time to sleep during those 20 hour days - either that or our Alaskan Mike is just hyperactive.

Mike's taken the basic stomp rocket idea and created a series of really nice models. This one will be a Gemini-Titan.


It looks like it'll be a great classroom (or first build) project. Few parts, good sized parts, nice fit, and excellent graphics.


It's your basic rocket body, tubes and conics. Roll the tubes/cones, cut and laminate formers, and attach. On the right is the thrust tube sized for a loose fit around a 1/2 PVC pipe. Note the length - limited by letter size paper. It reaches the full length of the first stage tube and up to the top of the black graphics on the second stage - a good reference point. The thrust tube slips into ring formers in the first stage and terminates against a solid former in the middle of the second stage - placed in line with the top of the second stage graphics.





This is a bit of re-jiggering of the basic model - I figured the air pressure from the stomp launcher would be better contained with a solid bulkhead to bear against rather than just glued to the inner edge of the formers.

While I checked the tabs for fit, I used a backing ring to join the stages as it helps keep the body straight. I also glued strips around the inner circumference to locate and align the bottom (ring) and top (solid) formers. All the other tabs were used as designed.


A bit of burnishing to sink a visible seam, and the bits are ready to assemble.



Obviously, you can't make the Titan thrust assembly since the pressure tube is in the way. Mike did provide two nozzles - here mounted with a little extra flair hoping they'd provide enough stern drag to replace the provided fins. No such luck - without the fins it tumbles fairly quickly. With the fins we're up to 30 feet with an easy stomp (not bad considering this is at least 5 times the weight of the basic 11" tube and fin rocket, which will easily make 100 feet).

Mike's designed this with a replaceable nose section - watch the fit carefully as the inner section builds to the same size as the outer as printed (should slip inside). Mike might adjust the part, but it's tough to size it exactly since various weights (or brands) of paper/card may vary in thickness.

Yogi

[bagpiper]

I was thinking the same thing about Mike, Yogi. I got an email from him around 04:00 this morning. :D

But he is indeed doing some wonderful stuff with his designs.

Thanks for sharing this build mate. I am very interested in this one.

Cheers
Jim

[Retired_for_now]

Thanks, Jim.

I usually just build models as printed, then they go into an indoor case (science center or planetarium) or to a classroom (short life expectancy). The tube-only stomp rockets are also uncoated - one piece disposables.

Mike's stomp rockets are nice enough I'd like to use them for demos or prizes - so need to be a little more durable. Following the recent comments on spray varnish/preservatives/fixatives I thought I'd try some on this one. Didn't make a run to the craft store, so decided to see how your basic Krylon clear coat would work.



One thin coat so far. No problems with the ink (HP-brand, not generic). I don't expect glue problems as I'm still working my way through the big bottle of Titebond II from my shop.

Still thinking about stability - how to eliminate the need for (inauthentic) fins. They're nicely done and subdued in Mike's rendition - but ...



The trick is to move the center of gravity (balance point) - CG - forward of the center of (lateral) pressure - CP. The rocket is a simple shape so the CP is about halfway up the body (just above the "N" in UNITED). The CG is aft (about at the "T" in UNITED) due to the weight of the pressure tube and associated heavy formers. I tried to splay out the nozzles to provide more lateral area and move the CP aft but, as noted above, it wasn't enough. The fins do the trick, but I'd rather not need them. So, how to move the CG forward? I'll try a bit of weight in the nose, though I don't expect that to be very successful. Stomp rockets need to be as light as possible so adding weight may just turn it into a shelf sitter.

We'll see,

Yogi

If you can stick a tube in it - it'll launch ...

[mbauer]

Hi Yogi,

Thank you for the catch of the replaceable nosecone assembly. Will fix ASAP.

Great photos and a big surprise! Thanks for showing these!

Just so that you know, after 4-weeks of drawing these rockets. 14 are done and the autocad drawing says 474.2 hours.

They do keep me off the streets at night...

Best regards,
Mike

[mbauer]

Originally Posted by Retired_for_now

Attachment 47579
It's your basic rocket body, tubes and conics. Roll the tubes/cones, cut and laminate formers, and attach. On the right is the thrust tube sized for a loose fit around a 1/2 PVC pipe. Note the length - limited by letter size paper. It reaches the full length of the first stage tube and up to the top of the black graphics on the second stage - a good reference point. The thrust tube slips into ring formers in the first stage and terminates against a solid former in the middle of the second stage - placed in line with the top of the second stage graphics.
Attachment 47580

Attachment 47581

Attachment 47585
This is a bit of re-jiggering of the basic model - I figured the air pressure from the stomp launcher would be better contained with a solid bulkhead to bear against rather than just glued to the inner edge of the formers

Attachment 47584
Obviously, you can't make the Titan thrust assembly since the pressure tube is in the way. Mike did provide two nozzles - here mounted with a little extra flair hoping they'd provide enough stern drag to replace the provided fins. No such luck - without the fins it tumbles fairly quickly. With the fins we're up to 30 feet with an easy stomp (not bad considering this is at least 5 times the weight of the basic 11" tube and fin rocket, which will easily make 100 feet).

Mike's designed this with a replaceable nose section - watch the fit carefully as the inner section builds to the same size as the outer as printed (should slip inside). Mike might adjust the part, but it's tough to size it exactly since various weights (or brands) of paper/card may vary in thickness.

Yogi

Hi Yogi,

Great build and beautiful photos!

The thrust tube can be made 1" longer. Don't shorten it as printed, just cut to the edge of the paper. The longer the tube, the higher it goes.

Great experiment to show the "impulse" power available.

If you take a piece of wood dowel and throw it like a spear, it will rotate and tumble every time. Rotation means it will twist and turn with the length facing the relative wind, not the front as first thrown.

When man started using the spear, the head did give more stability, so I'm curious if your experiment will work. Of course the final answer was tail feathers. This is why I supply the small subdued fins.

Yes, the thrust tube was an issue. The way this one was, didn't work at all. The fix was simple, yours is an excellent way to do it to, furthermore using your shotgun crimp method works even better.

My fix was to put a plug inside the thrust tube and then re-inforce with strips of cardstock, new models soon to be sent will use this method.

Got the Saturn V to about 25ft, and the tube held this time! The Saturn V weighs 35 grams.

The only thing that hasn't flown, was the F16 (30" long and weighs 4-oz). Working on a F104 that is 20" long and lots lighter.

One thing that I'll try next is to make the whole capsule assembly replaceable. Doing it this way might turn the whole section into a "shock-Absorber" by sliding down the fuselage, instead of crunching when they land.

The 1950s Sci-Fi model I designed will use this method, but I don't have time right now to build it. Got 5-others in line first...

Best regards,
Mike Bauer