ROL NEWS--Redesigned Econojet F20W Released

Redesigned Econojet F20W Released After Beta Testing August 13, 2003 Web posted at: 6:03 PM EDT

(ROL Newswire ) -- AeroTech, Inc. is pleased to announce that a new F20W Econojet motor has been released for manufacturing and distribution, after a series of successful pre-release "beta tests" this Summer at LDRS-22 in Argonia, KS and NARAM-45 in Evansville, IN.

The new Econojets are completely redesigned and utilize a one-piece molded glass-phenolic case and nozzle unit with a matching molded bulkhead. The bulkhead is retained in the case with a threaded joint, and a small amount of adhesive is used to seal the interface. Motor hook recesses are molded into the nozzle end of the case.

Customers will not need to peel the paper labels as with the prior design, due to the fact that the motor is .005" smaller in diameter and operates at a lower external temperature (the case is insulated with a thick paper sleeve and a smaller RMS-Plus delay element is used instead of the full-diameter delay). AeroTech is continuing to use paper labels because silkscreen ink does not adhere well to the molded case, and the motor lot number can be printed on the label.

Another new feature is a plastic ejection charge retaining cap in the forward bulkhead. The cap retains the ejection charge in the bulkhead much more securely than in the previous design.

Propellant weight remains at 30 grams, though the motor lost a minor amount of total impulse due to the use of the smaller delay charge. The F20W may still be shipped via U.S. Mail Parcel Post with no hazmat fee, or by FedEx.

The motors have been in development for approximately three years. AeroTech plans to implement the new configuration in the F23J Black Max Econojet as well, and eventually convert the G35W and G38J Econojet motors to a similar longer molded case assembly.

The redesigned Econojets were reviewed and approved by NAR Standards and Testing over one year ago.

Source: ROL Newswire Service

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IF I was paranoid, I would think that this announcement is a direct result of my criticism voiced below in another thread .. but this can only be coincidence, right?

I do welcome this new design as it appears superior to the old design....... shockie B)

Reply to
shockwaveriderz

I won a 2 pack of the F20's at the LDRS banquet. After firing one off at a local launch the first thing I noticed was the lack of spitting the F20 is know for ( I kind of like that noise). I also noticed it had a hell of a kick (bonus points). The overhaul of the BP assembly is great too. I can't count the number of engines I bought where the paper BP cover had shifted and dumped the charge out. The smaller diameter was the best of all the changes. No more peeling and de-gumming the moter to get it to fit (extra bonus points). Now, if AT could make them with a thrust ring it would be a perfect mid-powered motor.

Eric F. South Eastern Virginia Rocketry Association Virginia Beach VA

Reply to
Eric F.

Since they are mailable someone mail me one. I will give the person a USR gift certificate if they desire. I will keep it anon.

Jerry

Reply to
Jerry Irvine

To me the point of note is the CHOICE by AT to NOT put a thrust ring on during the engineering process. At that time it was nearly free.

Jerry

Reply to
Jerry Irvine

Point well received. Pennies for material and a _very_ small amount of machine shop time would have served the rocket community well. Jerry, every product must have a new selling point for the next incremental improvement in the line to help string along its survival. Come on, this is business after all.

Unless a thrust ring would alter motor geometry too much and a recert would be in order? I Don't know, so I'm asking here.

Patrick

Reply to
IceAge

Bummer. The econojet line was well known for its loud crackly sound caused by the WL propellant burning against the full diameter delay grain. Goodbye crackle. :(

Mike F.

Reply to
Mfreptiles

I had the same thought. It wa one of the nice features of the Dark Star motors.

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

Reply to
Bob Kaplow

I don't believe they are. The F21 is, but the F20 is over the 30g limit. Besides, you still need USPO approval to mail mailable motors. Unless you're a dealer, you can't do it.

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

Reply to
Bob Kaplow

The last MAJOR change didn't, so why would that MINOR one?

Reply to
Jerry Irvine

Got an email back from Gary. They considered the ring. It would have made the mold VERY expensive, so that the part could be removed after molding. I'm sure if someone wants to invest a few million, this could change...

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

Reply to
Bob Kaplow

Wrong-o.

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-- ""Remove "zorch" from address (2 places) to reply.

Reply to
Fred Shecter

Not true. The ring would have prevented part removal. What is a one piece mold would have become 2-3 pieces to be able to get the part out. MUCH more expensive.

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

Reply to
Bob Kaplow

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F20 and F21 are both 30 grams.

You are correct about the USPS shipping.

-Fred Shecter NAR 20117

-- ""Remove "zorch" from address (2 places) to reply.

Reply to
Fred Shecter

You seem confused. A thread is a separate part, the case is at least 2 parts anyway and the "draft" (ID) is yet another tool. I have not seen the case yet (someone send me an expended one with all initial parts recovered) but the nozzle is probably yet another.

Jerry

Reply to
Jerry Irvine

I got email about this from Gary and already posted a correction. The F20 is USPS mailable. If you're on "the list".

Say, I wonder if AT or other vendors would put us on their list :-)

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

Reply to
Bob Kaplow

The nozzle is part of the molded casing.

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

Reply to
Bob Kaplow

Throat/exit

Reply to
Jerry Irvine

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