Aerotech E20-4

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jef955

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I just bought a pack of these and was wondering if anyone else has used them. From what I understand they are pretty new. This is my first composite motor purchase, which I bought for my Estes Tomahawk. I have only used either D12's or an Estes E9 in it and I was just wondering what to expect - if it ever quits snowing here !
 

Initiator001

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I flew an E20-7W in my AeroTech Arreaux at Plaster Blaster 8 this past November. It was a manufacturer's demonstration flight. I used the supplied igniter.

The flight was good. :D

PB8-17 Arreaux away on E20-7W motor.jpg
 

hardinlw

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The 4 second delay is too short. Note that the Estes instructions call out the D12-5 and E9-6 as recommended engines (5 and 6 second delays, respectively). On an F engine, you'll need an even longer delay. That would be the F20-7. If you use the 4 second delay, the parachute will deploy well before apogee and possibly at a speed high enough to do damage to the rocket (snapped shock cord, zipper in body tube, etc.).
 

jef955

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The last time I flew it was on an E9-6 and it was quite a bit of a "cliff hanger" - from now on it's definately an E9-4 or the E20. Have you had good luck with the E20-7 in the Estes Tomahawk ? I certainly don't want to zipper the tube. And how does is it fly in modest wind ?
 

hardinlw

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I realize now I misread your post. I was thinking F20, not E20. I've never flown an E20, but I see that it's a 35 N-s engine while the E9 is 28.5 N-s. All other things being equal, the E20 would take a slightly longer delay than an E9.

When you say the E9-6 flight was a cliff-hanger, do you mean it had arced over and was coming down fast when the chute finally popped? That would suggest that the 6 second delay was long for the E9, but with higher thrust the E20 might well need a 7 second delay. You'd need to run something like Rocksim to be sure. My best point of reference in personal experience is the Aerotech Arreaux which is silghtly heavier than the Tomahawk (12oz vs 9 oz) and just a bit longer. For E engines, it uses the E15-7 and E30-7, both of which are 40 N-s engines. This delay seems to be dead on for the Arreaux, so I'd go with the E20-7 in the Tomahawk.

As far as wind goes, the faster the rocket is going when it leaves the rod, the better and the E20 has twice the peak thrust of the E9, so it's a much better choice for windy conditions.
 

jef955

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When I said "cliff hanger" it was headed straight for the ground - it had arced all the way over and it was movin let me tell you :y: I think the wind hit it just right also. I guess an E9-4 would be better for wind and maybe the E9-6 for dead calm. As far af the E20 - guess I'll just have to try it ! I'm guessing it will probably be OK with the 4 but the 7 second delay seemed a little long. Another problem I noticed is that the Estes retainer ring does'nt quite fit right around the end of the Aerotech motor retention ring when you twist it to lock it in the motor mount. I have'nt quite figured that one out yet I may try tape/friction fit but I'll prob have some other people look at it and see what they say at my next club launch. I'm hoping someone here will have had the same problem and may have some suggestions also.
 

n3tjm

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The E9 hardly has enough thrust for the heavy Estes Tomahawk (an E9-4 is a better choice). For the E20 I think a 4 second delay is to short, but dont worry, its an Aerotech. You have a good chance of getting a longer delay (I seen 4 second delays go as long as 10, hope that does not happen)
 
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MarkII

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The Aerotech E20 is brand new; it was only certified by NAR S&T on November 27, 2009. So we are all anxiously waiting for you to try it out and tell us all about it. :D

MarkII
 

Initiator001

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The Aerotech E20 is brand new; it was only certified by NAR S&T on November 27, 2009. So we are all anxiously waiting for you to try it out and tell us all about it. :D



MarkII

Well, I've flown one. ;) :D

The flight and performance reminded me of a E15 motor.

The E20 uses a new molded case with built-in thrust ring and a molded forward bulkhead like the AeroTech F32 SU motor uses.

All of this was done to lower the cost to hobby shops/hobby shop customers and get them interested in carrying AeroTech motors which could be used in brand "E" models, also.
 

bobkrech

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Larry and Doug identified the issues. The E9 is in general a poor choice for a larger rocket on anything other than a calm day. It simply does not have the thrust to accelerate it to speed fast enough to overcome a turn into a cross wind. The E20 has more than twice the thrust so it will get to speed more than twice as quickly as the E9 so your rocket is more likely to stay vertical. You will need a 7 second delay if you don't want a zipper.

Bob
 

Microspeed

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Great motors, I've flown 4 of them on two different flights, clustering 2 E20-7's with 2 D10-7's. Based on a test flight of a single D10 that had trouble lighting, my first cluster flight used a copperhead in the D10's and the stock Q2G2-esque ignitors in the E20's, and all but one D10 lit. The second flight used all of the stock ignitors with the same result. But the important bit is that all 4 E20's have lit right on cue so far :)

[YOUTUBE]6ZjbREIlQZc[/YOUTUBE]

(Video is by me, photo was taken by Reed Goodwin-Johansson)

lastyearstarce20x2d10x2.jpg
 

MarkII

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Larry and Doug identified the issues. The E9 is in general a poor choice for a larger rocket on anything other than a calm day. It simply does not have the thrust to accelerate it to speed fast enough to overcome a turn into a cross wind. The E20 has more than twice the thrust so it will get to speed more than twice as quickly as the E9 so your rocket is more likely to stay vertical. You will need a 7 second delay if you don't want a zipper.

Bob
My 42.5" long x 1.64" diameter FSI Eos clone has beautiful flights to about 1200 feet on Estes E9-4s, as it did, for example, on Sunday 8/9 at NARAM, which was not exactly a calm day. RockSim says that I should use an E9-6 with it, but experience has shown me that it it will deploy quite late with that delay if there is a breeze, whereas it deploys right at apogee with the shorter delay in such conditions. I wasn't expecting the performance that I have gotten with it, based on all the comments that I have read about the E9. The empty weight (with nylon parachute, 29/24 motor mount adapter and metal retainer ring but without motor) of my Eos is about 7.5 oz., which is almost 2 oz. lighter than the manufacturer's stated weight of the Estes D Region Tomahawk that jef955 wants to launch, though. I wouldn't mind trying it on an E20 sometime, but the E9 is right now my favorite motor for it. But that nominal extra 2 oz. could make a critical difference for the Tomahawk.

MarkII
 
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Handeman

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My Estes D-Region Tomahawk was slightly modified. I know it doesn't do you any good now, but it may help others that want to try composites in the Tomahawk. I left the Estes motor retaining ring off because it won't fit if you use a 24/40 Hobbyline case. I also shifted the motor tube down slightly and left the thrust ring out completely. You have to adjust the upper MMT cap placement, but it worked out fine. I also added a 1/8" tubular Kevlar loop attached to the MMT and extends a couple of inches out the top of the BT, instead of the fold and stick elastic shock cord that came with it. The final weight with recovery but no motor is 9.6 oz.

I use 1/4" wide tape for a thrust ring on D12 & E9 motors and the built in ring on 24/40 cases. I wrap tape around the MMT and motor for retention. It's flown great of F39T & F24W reloads.

DRegion001.jpg


DRegion002.jpg


DRegion003.jpg
 

jef955

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Do you all think using tape for a friction fit would be sufficient or is that asking for trouble considering the Aerotech casing ? I'm already using a reducer for the shorter casing. And I did notice with the Estes E9 it took a while to get going off the pad. I have a feeling the E20 will be perfect - if I can keep it from going out the rear end :eyepop:
 

jef955

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Actually what do all think of this idea - instead of putting the 1" spacer in front of the motor, put it in the rear. the Aerotech motor will go far enough inside that the retaining ring catches the end of the motor mount tube inside and stays firmly in place. Put about a 5/8 inch spacer (prob old motor casing section cut down) inside the gray Estes retaining ring and lock it in the bottom of the rocket. The end of the motor nozzle sits about 3/8 of an inch inside the retainer ring, but looks close enough that it may not get beat up too bad from the flame coming out of the nozzle. Any thoughts ? And MarkII I just weighed mine it is 10.8 oz no prep/motor etc - heavier than I thought !
 
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jef955

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I forgot to post this a while ago but the Aerotech E20-4 launched my Estes Tomohawk like a .308 rifle round ! It is by far the most powerful motor I ever used. I think a much better choice would have been the E20-7. The shorter delay ejected the chute too early and ripped the chute, nose, and still attached shock cord from the model and it drifted off into the sunset. The rest of it came back down and with the exception of 1 popped fin, was completely intact. The traditional Estes shock cord mount was a complete waste of time (learning experience here!) and the rocket was just going way too fast at ejection. Go for the 7 second delay and be prepared for one hell of a flight !! :surprised:
 

cjl

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I forgot to post this a while ago but the Aerotech E20-4 launched my Estes Tomohawk like a .308 rifle round ! It is by far the most powerful motor I ever used. I think a much better choice would have been the E20-7. The shorter delay ejected the chute too early and ripped the chute, nose, and still attached shock cord from the model and it drifted off into the sunset. The rest of it came back down and with the exception of 1 popped fin, was completely intact. The traditional Estes shock cord mount was a complete waste of time (learning experience here!) and the rocket was just going way too fast at ejection. Go for the 7 second delay and be prepared for one hell of a flight !! :surprised:
The composite motors definitely have an impressive kick when you're used to BP :D
 

jef955

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I could'nt believe the difference. Especially at how fast it lifted off - it seemed to almost jump.
 

edwinshap1

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The E20 is great, but an E15 is a full E, which means its a 40 Ns motor, which is the maximum for an E. The E15 doesn't have as much initial kick, but it'll give a longer burn, and still be way more powerful than the estes E9.

I put a few in some minimum diameter rockets, wrapped some tape around the bottom (no thrust ring, or inside motor retention) and one ended up too high for me to see and i lost it, and the other i forgot to put wadding in so the chute disintegrated), but the other went up and came down perfectly. If you're going to fly heavier rockets, or on a large field, you should invest in a reloadable motor casing. You get much cheaper reloads, and the price is better overall after a few flights :)
 

dave carver

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Actually what do all think of this idea - instead of putting the 1" spacer in front of the motor, put it in the rear. the Aerotech motor will go far enough inside that the retaining ring catches the end of the motor mount tube inside and stays firmly in place. Put about a 5/8 inch spacer (prob old motor casing section cut down) inside the gray Estes retaining ring and lock it in the bottom of the rocket. The end of the motor nozzle sits about 3/8 of an inch inside the retainer ring, but looks close enough that it may not get beat up too bad from the flame coming out of the nozzle. Any thoughts ? And MarkII I just weighed mine it is 10.8 oz no prep/motor etc - heavier than I thought !
Ok, you don't want to place the spacer on the nozzle end of the motor. Recessing the motor up in a tube will cause the motor to act like it has an extra large nozzle, spreading the thrust and cause it to not produce the lift you expect due to over-expansion.
 

Initiator001

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Here's a picture of my Estes Eliminator model launching on an AeroTech E20-10W motor at NARAM-52. :)

N52 Estes Eliminator launch.jpg
 

Handeman

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I forgot to post this a while ago but the Aerotech E20-4 launched my Estes Tomohawk like a .308 rifle round ! It is by far the most powerful motor I ever used. I think a much better choice would have been the E20-7. The shorter delay ejected the chute too early and ripped the chute, nose, and still attached shock cord from the model and it drifted off into the sunset. The rest of it came back down and with the exception of 1 popped fin, was completely intact. The traditional Estes shock cord mount was a complete waste of time (learning experience here!) and the rocket was just going way too fast at ejection. Go for the 7 second delay and be prepared for one hell of a flight !! :surprised:
Two things here.
  1. Yes, the delay was too short and should have been longer. I'm not sure that cause all the problems with the recovery system.
  2. The amount of ejection powder supplied with composite motor is more and provides a more energetic ejection then the BP motors. You don't have to use all of the powder. On some rockets it's better to use less powder.
 

o1d_dude

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I bought a two-pack of the E20-4 motors today and plan to use them tomorrow at our monthly club launch.

I fly tube fin rockets almost exclusively so I look for the shorter delays. Those tubers have the coast phase of a crowbar if you know what I mean.

One E20 motor goes in my E-Pod...the E30 motor last Saturday at Snow Ranch was redonk-u-lous. The second motor will boost my mostly stock Estes Super Neon XL which positively ate up the E30 last week. That is the motor Estes must have had in mind when they upscaled the Super Neon but I want to see how it flies with the E20.
 

Rex R

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I've flown an E20-4 in my interceptor e, nice flight, good for a 10mph breeze. and I've flown my big bertha on an E20-7...that was...interesting :). it didn't quite teleport off the pad, however I think I'll wait till the snow goes away before I try that again! (long walk through snow) my bertha was recovered w/ no damage :).
 

TopRamen

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They give my TLP Martel AS;37 a nice Ride:

[video=youtube;FHFeGZLoORE]https://www.youtube.com/watch?v=FHFeGZLoORE[/video]
 
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