making a large sonic boom?

whats "IMHO" mean????????? I woder if I bought one of those "vortex" footballs with the whisles, cut the whistles off and stuck em on a rocket..... THAT would make any rocket that can fly scream!! I guess I prefer the real BOOM, or whatever will happen to the whistles, though. didn't Estes make a rocket that made funny noises???

IMHO. In My Honest Opinion.

Whenever using a sim program, it's best to weigh the rocket yourself with an accurate scale. Don't use a bathroom scale. Weigh it with the recovery system only. No motor. Put that weight into the sim program. You'll get a much more accurate simulation.

Yeah, F101Ts are really cool. Core-burning 24mm blue thunder motors. I have an F72T. It's the same size but it has a C-slot. The only way to fly them, is to put them in a 24mm minimum diameter rocket. Just use a single section of 24mm tubing about 15 inches long, add a nosecone and some balsa fins. Make sure you put some lightweight glass over the fins. Put in a long streamer made from flagging tape found in the sporting goods section of WalMart. It couldn't hurt to put in some chalk dust for tracking powder. Make sure you check stability!

You may or may not get it back. Most likely you will not. I launched one of those on a G55 at NARAM45. It sims at 4,500 feet at about mach 1.25. I'm pretty sure it did all of that and more. I saw the ejection and never saw it again. Dan, on the other hand, launched a 24mm minimum diameter on an F101T at our local club. Like he said, whiplash was felt all around. We all lost sight of it for a while, when someone happend to look over at the high power pads. He says, "There it is." It landed 200 feet from us with no damage at all. And it was pretty windy that day! It was sweet.

Here's a pic. The unpainted one flew on a G80 and went wildly unstable (remember when I said to check stability? That's why). The black one it the one that flew on the G55.

Originally posted by Neil
whats "IMHO" mean?????????

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IMHO = In My Humble Opinion

Abbreviation Station

The reason I asked about the weight of the Mach Buster was that 12oz seems really lightweight for it’s description… a 3 foot long glassed airframe, solid urethane nose cone and Acme fin can. Did you weigh it or are you going solely by SpaceCad?

Just Curious.

-Scott

Honest. Humble. Same thing. I was actually thinking humble and I typed honest. Honest!

LOL

well, honestly, I went with Spacecad and added quite a bit cause it could not do glassed airframes, or fin cans. It was either 6-8 OZ dry, which I knew was waaaaay off, so I took it to the only scale I had, and weighd it, and enterd that in. I will be getting a GOOD scale from my dad's office soon.

Hmm....weigh the thing directly instead of using programs to weigh it. To use one of my rockets, my Magnum is 11# dry in real life, it came in at 6# in Rocksim. Quite the difference if you ask me, you have to factor in epoxy and other stuff.

As soon as I get a scale from my dad....... My mom will not let me buy one. she does not see why I would need it.

The solution to all your buying needs.....EBay. Get a cheap used one, sure, it may be beat up a bit. But it just makes it that much cheaper for you, and works just as good. Prettiness is not a large factor on scales!

My mom will also not let me use Ebay. it really stinks. I guess I could talk her into it if she was in a good mood, my dad had just gotten a paycheck, and I had a lot of time, but the chances of all that happening at once are slim-or-none. maybe if talk my DAD into it first..... he is much closer to understanding my roceketry needs.

Hi guys,

Sorry to go off topic, but this reminded me of a story. Many years ago I was friends with a former SeaBee (CB = Construction Battalion...these are the Navy field engineers...they like building runways while under fire). One of the weapons in their inventory is a big honkin' 4.2" diameter mortar. We were talking about it one day.

"You know," says my friend, "when you shoot this mortar, it doesn't make that little 'poonk' sound you hear in the movies."

"It doesn't go 'boom' either."

"It doesn't even go 'KA-BOOM!'"

"It goes "KA-F@(%ING-BOOM!!!"

I still chuckle when I replay this in my head

Check with your local post office, or at the pharmacy counter at the grocery store. Both places have rather accurate scales. If you go in when they are not really busy, and don't make it a habit to ask for this service four times a week, I'll bet they will be happy to help you and weigh your rocket.

If you go to the post office, be SURE to emphasize that you have a model, that it is made of cardboard and plastic, that it has NO motor or chemicals of any kind (we don't want to see your photo on the bulletin board at the post office next week).

Or, sometimes the hardware stores have pretty nice scales you can use in the 'bulk' hardware section (where people weigh out nails, sheetrock screws, etc). Or try a plant nursery (where they weigh out seed for sale). Look around. It never hurts to ask.

Originally posted by Neil
As soon as I get a scale from my dad....... My mom will not let me buy one. she does not see why I would need it.

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Your Mom is right, A scale in NOT a necessity.

It's the same as a measuring cup for baking cookies. It is possible to bake cookies from scratch without using a measuring cup... just dont ask ME to taste test them.

The NRA safety code and the FAA require that you do certain things depending on the weight of your rocket.

If you fly at club launches where they weigh your rocket before allowing you to fly it... you can skip buying a scale as long as the launch has a standing FAA wavier.

Now here is why a scale (even an inexpensive postal scale) can be a good thing to have...
A farmer near your house says you may fly rockets on his field whenever you want. You think this is really nice! You load an F50 into your Mach Buster and fly on his field. - You thought the rocket was 12oz - but it was really 14oz empty - with the F50 it was 17oz and over the FAA weight limit for model rockets. You never filed for an FAA wavier.

My point is that the exact weight of your model can be an important thing to know. You might want to remind Mom about that.

AND, I will be flying motors that have lost cert status years ago soon, and I would like to know the wieght. by the way, on the farmer thing, I WISH!!!! NO farmer near me (as to my knowlege) has a field big enough for any aerotech engine. I will be flying that Synerjet motor (F32) with a Mustang, and a streamer. no chute. it would drift right into the woods.

Originally posted by Neil
AND, I will be flying motors that have lost cert status years ago soon

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Huh?

Will you be doing this at a TRA/NRA club launch ?

Doesn't this violate the safety rules ?

Doesn't this void your NAR insurance ?




Do you belong to a club that allows flying non-cert motors at the club launch site?

- Just a stupid question....

thats half the point of the scale. I have to fly at a non-club launch (I know of a field that I will use if there is no on near it). just makin sure, but that only voids my NAR insurance for that DAY, or FIGHT, not for life, right??? the motor is a synerjet F32-8, synerjet went out of buisness in 1994, but stephen boy got me this to use in one of my experiments. the experiment origionnaly was age, but it may have to become core burning vs. slot burning, once I find out how that motor looks inside. I have tried to see in with a flashlight, but it is not working. oh well. I will find out soon, i do not know how, but I have a feeling!! assuming i ever get the rocket and altimeter i need from rocketmotion. been 2.5 weeks since I ordered the thing:kill: :kill: :kill: :kill: :kill: :kill: :kill:

what altimeter are you getting?