More Half-Baked Designs Thread

[BigMacDaddy]

Has anyone seen someone make a Kyushu J7W1 into a model rocket? I saw that @KenECoyote mentioned this one. I became intrigued by the idea of making a propeller spin on launch with the P-38 model. However, in that model [I think] the drag of the propellers would likely have a destabilizing effect since they are so far forward. In the Kyushu the drag of the propeller would help with stability.

 

[BABAR]

Make a ZELL F-104 into a 2 stager: First stage is using the booster to get it off the pad. Second stage is the tail motor lit at booster burnout. Some other ZELL subjects to consider are the Firebee, Mace, and Matador.

My favorite Firebees are the early retro versions. They recovered by parachute. There are 72nd and 48th scale plastic kits available to scale from.

It would give you whole new category of thrust lines to evaluate.

not sure if the dimension work out, but there is always the PMC route.

https://www.bing.com/shop/productpa...rue"&productpage=true&FORM=SHPPDP&browse=true

 

[Richard N]

There was a proposed jet version of the Shinden. Shinden glider models fly fine without spinning propellers.

Concerning freewheeling props, they don’t accomplish anything but creating drag and reducing flight performance. On electric powered gliders, a freewheeling prop is an air brake that will destroy its glide performance. When their props are not powered, they are stopped and folded to reduce drag.

 

[Richard N]

That 1/48 scale Firebee model is about 5” long. Too tiny to make a flying model of, but an excellent scale reference. There are a couple of real ones at the Missile Garden at White Sands Missile Range in New Mexico.

 

[Richard N]

The jet Shinden is the Kyushu J7W2 Shinden Kai and there is a 1/48 plastic kit available: https://www.ebay.com/itm/304682464664

 

[jqavins]

That's right, those are cross holes through the body and nose cone. Shown approximately to scale with a BT-70 body tube, BT-50 tubes pushed through it, plus a BT-20 and a BT-5 pushed through the nose cone. Not shown, it would use tube fins (or course).

I call it "What The Frank?"

 

[jqavins]

Thanks to this conversation, I've been thinking about a good rocket for demos. It has to be eye catching on the ground and big enough to remain visible up to a respectable altitude, whatever that might be for a given field. And it should take a good range of engines to reach said respectable altitude for a given field.

So, how about a stretched Big Daddy? Double the total height including nose cone, painted in a vibrant red-white-green "Christmas barber pole" on the body, ultra gloss black nose cone, and mirror fins. Use a good size yellow and purple parachute with bird scare streamers attached to each shroud line. Give it a 29 mm motor mount for the F15 and E16 engines where appropriate, and easily adapt down to D12, C11, and smaller, and that's just Estes engines. Build it with plywood CRs and fins, so when the public doesn't need to be able to see it at apogee it will take H and probably I motors.

 

[jqavins]

While posting the above, and seeing the one above that...

Not shown, it would use tube fins (or course).

No, on second thought, swept trapezoids with lightening holes.

 

[jqavins]

A piñata rocket.

Take a BT-80 payload tube, and glue couplers into both ends, with CT-80 to BT-50 CRs. Then cut that subassembly lengthwise in half. The booster section (i.e., the tube below the payload) has a stuffer long enough to duct ejection gas all the way through the payload and out through the upper CR. The nose cone is glued to another piece of tube that also includes the laundry (recovery section).

The two halves of the payload tube are inserted into the booster tube, where the booster tube holds the two halves together. The payload tube is filled with candy. (Hmm, the upper CR is in the way. I'm sure we can work that out.) The recovery section is brought down on top of the payload, holding the two halves together at the upper end.

When the ejection charge fires, the ejection gas is ducted through the payload section, isolated from the candy. When the recovery section is blown off, the two halves of the payload tube fall away, like a space launch vehicle's payload faring, releasing the candy.

The various pieces of rocket are connected by Kevlar chords as necessary, attached wherever; no need to work that out right now, since this is supposed to be half baked.

Does dropping a payload of candy violate the safety code? I don't think it does.

 

[BABAR]

Does dropping a payload of candy violate the safety code? I don't think it does.

no, but if it contains 125,893 calorie-seconds or more you need an FAA waiver.

 

[jqavins]

"calorie-seconds"? Of what (energy times time) is that a unit?

 

[Raythain]

"calorie-seconds"? Of what (energy times time) is that a unit?

It measures how long the kids will be absolute terrors on their sugar rush.

Divide the total calorie-seconds by the number of children consuming the candy, and the time in seconds is how long the parents need to hide in the bathroom or keep the children outside.

 

[BABAR]

A piñata rocket.

Take a BT-80 payload tube, and glue couplers into both ends, with CT-80 to BT-50 CRs. Then cut that subassembly lengthwise in half. The booster section (i.e., the tube below the payload) has a stuffer long enough to duct ejection gas all the way through the payload and out through the upper CR. The nose cone is glued to another piece of tube that also includes the laundry (recovery section).

The two halves of the payload tube are inserted into the booster tube, where the booster tube holds the two halves together. The payload tube is filled with candy. (Hmm, the upper CR is in the way. I'm sure we can work that out.) The recovery section is brought down on top of the payload, holding the two halves together at the upper end.

When the ejection charge fires, the ejection gas is ducted through the payload section, isolated from the candy. When the recovery section is blown off, the two halves of the payload tube fall away, like a space launch vehicle's payload faring, releasing the candy.

The various pieces of rocket are connected by Kevlar chords as necessary, attached wherever; no need to work that out right now, since this is supposed to be half baked.
.

"calorie-seconds"? Of what (energy times time) is that a unit?

Depends on how fast you eat.

 

[BABAR]

no, but if it contains 125,893 calorie-seconds or more you need an FAA waiver.

Over 200,000 calorie-seconds you need a WWA* waiver.

*WAA: Weight Watcher’s Association

 

[jqavins]

OK, this one is not all of half bakes. Maybe a fifth baked. Maybe half assed.

Start with a square tube like Nu Way kits. And then, for the nose, first part of a steep pyramid then capped off with a normally slopped pyramid. It would be the square version of a bicone nose, but it would also be, wait for it...

the Illuminati.

Put the single eye symbol on the the sides of the upper cone. Also duplicate the two slot motif and eye symbol on the fins. Paint a stripe on the nose cone and on each fin at the right at change of slope, designed to emulate the gap that belongs there. come to think kf it, the gap for the fins could real; split fins are no big deal. And (I'm just thinking this up while I'm typing) you could also make the gap in the nose pyramid real buy having a connecting piece at the center where it's hard to see.

 

[neil_w]

If you want to recreate the look of the little pyramid floating above the top of the rest of the pyramid (technically a frustum, I believe) then why not just attach the little pyramid to its base with a narrow tube? Then it would really look more like it's floating.

 

[jqavins]

Isn't that what I wrote there at the end? OK, I wrote "piece" not "tube". I piece of tube was in my head, but it could also be a right rectangular parallelpiped (I'll see your frustum and raise you that) or some other shaped chunk of material, be it solid or hollow.

 

[neil_w]

Sorry, you’re correct of course. Apparently I replied before finishing reading your post.

 

[BABAR]

If you want to recreate the look of the little pyramid floating above the top of the rest of the pyramid (technically a frustum, I believe) then why not just attach the little pyramid to its base with a narrow tube? Then it would really look more like it's floating.

Sooooo, an exercise is frustrumation?