"Fastest" E engines available?

[DynaSoar]

I'm working on a competition bird (my experiments with folded styrene fins having worked out quite well). The design works far better with "kicker" motors than with sustained thrust. What's the fastest burning E engines available? I see some Aerotech E30s are available, but the SpaceCAD database shows an Aerotech E50. Is that an RMS, or discontinued, or what?

 

[astrowolf67]

What size motor mount are you using? I assume a 24mm mount since you mentioned the E30's. The E30 is, as far as I know, the fastest burning in the 24mm range. Or, the E28, for the 24mm RMS.

 

[DynaSoar]

Originally posted by astrowolf67
What size motor mount are you using? I assume a 24mm mount since you mentioned the E30's. The E30 is, as far as I know, the fastest burning in the 24mm range. Or, the E28, for the 24mm RMS.

Sorry, yes, 24mm. Single use preferred.

 

[gothique_97]

The E50 was made by AeroTech up until not too long ago [maybe 7 years ago?]. It was a 24mm x 2.75" 40 N-sec E that burned in 8/10ths of a second. I flew a couple of these, purchased from AAA Model Aviation Fuels [long out of business]. Definitely butt-kicker motors, especially in Estes kits.

If you do find anybody still selling them, let me know. I'll do the same.

The only E motor that I knew of that burned faster than that was the FSI E60; a 27mm 30 N-sec black powder E that burned for half a second. And I think a company called Vulcan made a 29mm E55.

You might still be able to find 24mm F101s; a full impulse F that burns in 8/10ths of a second. Call Kevin Nolan at Countdown Hobbies to see if he has any [that's who I last bought one from].

 

[Initiator001]

While not 'available', the "fastest" E motor I know about is the E110 which was developed by Scott Pearce at AeroTech.

It was in a standard 24mm x 70mm single-use case.

Scott flew a few of them. WOW!

 

[n3tjm]

Interesting note: the E60 and F100 actually burned longer than a half second. They had a sustainer after the thrust spike that burn for anonther three-tens a second or so... but it was so low in thrust that most published thrust curves don't show it. Kinda like the estes A10's (which are really A2's), For the longest time, Estes put the thrust curve in their catalog and motor instructions to show the A10 having just a 12N max spike that lasted about a quarter of a second. Now they publish the true thrust curve... showing the extremely low thrust sustainer that prolongs the motor burn to .8 seconds...

Motors like these add suspense to staging rockets... You get the loud woosh, and the then a moment of relative silence... prolonging the staging sequence... making you think (or say) "Come on Baby! Stage!"

Related Article: Staging Mongoose with A10-0T's

Back on Topic: The fastest E motors I have seen are Kosdon E40's, no longer certified, and are 1" in diameter. Then there was the 18mm E45, which was a full E. That was an awesome motor. Also decertified

 

[Initiator001]

Originally posted by n3tjm
Then there was the 18mm E45, which was a full E. That was an awesome motor. Also decertified

Ah, the AeroTech 18mm diameter E45 motor.

That's an interesting story.

Okay, history lesson time!

Waaaay back, when Scott Pearce and I both worked for AeroTech, we were fans of 'The Hitch-Hikers Guide to Galaxy'.

One day, we were talking about 18mm diameter motors. I was thinking it would be neat if a 'full' impuse 'E' motor was available in 18mm. Scott was saying it would be nearly four inches long. I said that was fine. Scott ran the motor program on the computer and came up with a workable design.

Scott shows me the data and then tells me that it would work out to be an E'42'. I looked at him and said we need to make some of them.

A few days later, Scott had produced some sample E42 motors for testing. The motors were fired on the thrust stand and the data reduced.

They worked out to be 'E45'. Manufacturers are allowed to designate their motors any performance label as long as it is with-in 5% (I think) of it's true value.

We decided to leave it as an E45 as we had a new idea: An 18mm 'F' motor!

Again, Scott ran the numbers. It would not be a full impuse 'F' and nearly five inches long.

Scott produced a few test motors wheich were fired. The data reduced to 'F55'.

At that point, we gave up. The motors did go into limited production.

Later, Scott and I would revisit '42' and this time it would be successful. But, that's a story for another day.

 

[n3tjm]

I remember them F55's too... great little motor. I saw Ed Miller shread one of his rockets with it... He gave me the spent case. I wonder what happened to it

Think Aerotech has any plans to bring those motors back?

 

[gothique_97]

Originally posted by Initiator001
Waaaay back, when Scott Pearce and I both worked for AeroTech, we were fans of 'The Hitch-Hikers Guide to Galaxy'.

...

Scott shows me the data and then tells me that it would work out to be an E'42'. I looked at him and said we need to make some of them.

Is this also how the 24mm G42 came into being?

 

[Rocketjunkie]

Originally posted by Initiator001
While not 'available', the "fastest" E motor I know about is the E110 which was developed by Scott Pearce at AeroTech.

It was in a standard 24mm x 70mm single-use case.

Scott flew a few of them. WOW!

Still have one

 

[Initiator001]

Originally posted by gothique_97
Is this also how the 24mm G42 came into being?

Patience, Grasshopper. All will be revealed in time.

 

[Initiator001]

Originally posted by Rocketjunkie
Still have one

Me, too!

 

[DynaSoar]

Originally posted by n3tjm
...certified...

<homer> D'OH! </homer>

I think that pretty much narrows down the possibilities for me, and I know where that list is. I want to try for the E altitude record so I have to stick with certified engines. I'd still like to try to bust Mach 1 on an E (SpaceCAD says I can get Mach 1.05 on an E50) but that's not a competition event.

 

[n3tjm]

Originally posted by DynaSoar
<homer> D'OH! </homer>

I think that pretty much narrows down the possibilities for me, and I know where that list is. I want to try for the E altitude record so I have to stick with certified engines. I'd still like to try to bust Mach 1 on an E (SpaceCAD says I can get Mach 1.05 on an E50) but that's not a competition event.

If you want to go for altitude.... us an E6 in a very light weight rocket. General rule... a rocket will go higher with a longer burning motor with the same total impulse as a quick burning motor. The reason for this is the quicker burning motors will make the rocket go faster, but every time the rocket doubles its speed, the force of drag quadruples.

 

[DynaSoar]

Originally posted by n3tjm
If you want to go for altitude.... us an E6 in a very light weight rocket.

After my CAD work, I'd figured that out. I have a couple Apogee Es on the way for that reason. I'm after the Mach thing as a matter of picking up where I left off with the hobby 20 years ago. The first Mach 1+ flights were just going on then. Doing so now is no big deal, but I can still try for it on a minimum of power.

As for altitude, I'm confident the design can beat the record. SpaceCAD gives me an altitude result of 3500+ feet on an E6. The C record is about 1600. The problem then, and I suspect the reason the record is so low, is making something so small visible enough for tracking and recovery. I'm betting plenty of others beat the 491 meter record but lost it in the process.

 

[bobkrech]

DynaSoar

Both C and E altitude records are higher in different divisions.

The NAR Adult Division C altitude record of 756 m (2480 ft.) was set on 8/7/90 by Jim Sexton.

The NAR Team E altitude record of 1387 m (4550 ft.) was set on 5/11/85 by the Lou Dick Team.

https://nar.org/NARrecords.shtml

You need to use minimum diameter motors and rockets to obtain maximum altitude. A 13 mm Apogee C6 class motor in a ~50 gm minimum diameter rocket probably set the C Alt record. A 24 mm Apogee E6 class motor in a ~75 gm minimum diameter rocket probably set the E Alt record.

Bob Krech

 

[DynaSoar]

Originally posted by bobkrech
DynaSoar

Both C and E altitude records are higher in different divisions.

The NAR Adult Division C altitude record of 756 m (2480 ft.) was set on 8/7/90 by Jim Sexton.

The NAR Team E altitude record of 1387 m (4550 ft.) was set on 5/11/85 by the Lou Dick Team.

https://nar.org/NARrecords.shtml

I meant division C, not C engine.

That's where I got the figures from:

Rule # Div Event Record Date Holder
20 c E Alt 491 m 8/16/03 Steve Clapp

That's 1611 feet. I figure I can double that. If it were designed for weight instead of speed could do better, but as is it should break this easy.

 

[bobkrech]

DynaSoar

I agree. You should easily be able to double, and indeed almost triple the current division C E-altitude record.

Even the Division C Single Egg Loft record of 1187 m, or 3894 ft set on 8/7/02 by Steve Humphrey, and the Division C Double Egg Loft record of 654 m, or 2146 ft. set on 7/29/97 by Trip Barber, are much higher than the current Division C E alt record of 491 m, or 1611 ft set on 8/16/03 by Steve Clapp.

My guess is that the event is a relatively rare one because you need a really big field for the event, visual tracking at that altitude is difficult, and recovery and return of the model is not certain due to winds loft and drift.

Go for it.

Bob Krech

 

[gerbs4me]

Those E30's are fast
one awesome little motor