Nozzle question

That's so inside baseball!

They're both bastards!

I want a D40 (E9 case) and I want to see that plug!

nozzle than the current A8's/B4's. The A8-0 is definitely a thin wall, metric, modern motor, but it's obvious they changed the nozzles at some later time.

Yes the old A8's actually tested out to near 8n average thrust, the newer ones test to about 3n - creative labeling on Estes' part. They streamlined production to reduce costs, I don't know all specifics but the larger nozzle is part of it.

Dale Greene

So could one place an order for say $5000 of "old" A8's?

Jerry

So how deeply can an E9 be cored before it becomes catostrophic?

Is that catostrophic while you're coring it, or when you go to launch it?

So why are they not required to call them A3s ?

What good is certified motors if the consumer is not getting what he thinks he is ?

Good question - I don't have a good answer. I've been in manufacturing and sales for over 30 years now and I realize that all advertised values are "nominal" which means you won't get more ,you might get slightly less,but if my company's figures were off that much our competitors would eat us alive.

Well, you do have the ability to check the actual test data on the NAR website - a resource the manufacturers won't provide

Dale Greene

Think that's bad? I just went and looked -- the A10-3T has about 2 Newtons average thrust.

David Erbas-White

Dale Greene wrote:

Have you seen the 'A10' data? According to the NAR datasheet its actually an A2.35

Then again, in some cases, the 'NAR'-style designation may itself be misleading - for example in the case of an extremely regressive or progressive motor, where the thrust at ignition is significantly different from the average thrust figure.

Hybrids motors also have more complex thrust curves - the thrust during the liquid N20 part of the burn is often higher than the average, which is 'brought down' by the portion of the burn where gaseous N20 is contained in the tank.

For example, the HT J330 (835CC172JFX) has a thrust of around 500N at ignition which only drops to 330N just before the gaseous (blowdown?) phase begins.

Have a look at

Yes, I knew that , thanks Dave.

What I was dogin' about however, was that they should be told to change their marketing labels, if they want to maintain certification.

But you HAVE competitors.

This market is "managed".

Point.

To form a monopoly for the SELLERS, who author the rules?

Just a guess from a guy who was IN THE ROOM at the time the rules were INSTALLED.

Jerry

Start with 1/8" x 1/4" and as you go deeper, widen the core and the nozzle too.

Report successful mods.

Are you taking responsibility?

The A10 has a very large spike from its core, followed by a long low sustainer. If it were marked an A2, unsuspecting users would shread models, and especially BGs. The 10 represents the spike, which contains about 50% of the total impulse.

Several old FSI motors were similar; a big spike followed by a long low thrust sustainer. The D18 is the classic example, but even motors like the D20, E60, and F100 exhibited some of that. So did the Rocketflite BP motors.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

OK, so what formula is being used to arrive at the '10' number? There ought to be some way of correlating the numeric value assigned to a motor to the thrust levels. Is it supposed to be some percentage of 'peak'? Is it some weighted value of peak*time vs. sustain*time? One ought to be able to determine SOMETHING from the designations.

David Erbas-White

Then, of course, there was the G008...

-dave w

The number is supposed to be the motor's average thrust. In the case of the A10, and some of the old FSI motors, it's the average of the spike, ignoring the sustainer thrust. Although in the case of the A10, even that isn't enough: the spike alone would be a 7 not a 10.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Well, unless they looked up the datasheet.