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Aerotech RMS tips. Brought to you as a public service (grin).
I'm having trouble with the E and F reloads for this casing. The delay charges seem to be much longer than advertised, and I'm breaking rockets. An E16-4W gave me a 12 second delay. The recovery charge fired several seconds after the rocket core sampled. An F40-4W fired the recovery charge after about 8 seconds, by which time the rocket was too low to deploy its chutes. Does anyone have any experience with this? [numerous me-too replies]
- Steve Ruane 7-00

In that vein, at the first UROC launch, I saw more delay problems than I ever have before. I started quizzing people on what their delays looked like (did you have a spacer? Big, or little spacer). There were motors that were obviously long delays that came from motors labeled as medium delays. I saw motors that were obviously short delays that were labeled medium. I think that the conversion from old to new delay system has created a bit of a problem at Aerotech. You should carefully examine your
delays before installing them.

I think we need to assemble a table of what the darn delay kits look like.

"The time is always right to do the right thing." -- Martin Luther King Jr. David Urbanek, Rocky Mountain Rocketry

For example, three weeks ago I had to cut and sand 3/16" off a Kosdon grain to get a K350 to fit in the case. I then used the motor for my [Tripoli] L2 certification flight. My point being, every time I go to a launch I see someone filling/cutting/sanding Kosdon motors to get them to fit properly.
- Bryan Flynt 8-00

To me, that's the deciding factor. I fly enough mid-power stuff that I don't want to spend a lot of time doing cleanup/reloading between flights. I'd rather spend a little more and get single-use motors. Just pop out the old one, pop in a new one, pack the chute and wadding and you're good to go. Larger motors are better suited for reloadables. I don't usually fly them several times in a day, so the cleanup and reload time between flights isn't a factor, and the cost savings is much more significant at those sizes too.
- Ray Dunakin 2003

The club I'm in had 39 Aerotech Mirage launches yesterday. All were on G40-4W's or G80-7W's single use. The 4 second delays ejected from immediately after burnout to 7-9 seconds. Actually 2 never ejected. The 7 second delays seemed to go from 4-9 seconds also. So it all seemed hokey to me.
- Greg Cisko 2003

Case in point; Aerotech Strong Arm. First flight on a F40-7W reload. Extremely long delay, and chute finally opens after much encouragement approximately half way past apogee. Second flight on a F52-8T reload. Chute opens after rocket drills a 4 inch hole in brother-in-laws hay field. No oil was struck and rocket was destroyed.
- Lew Garrow 2003
I see the following motors recommended for the "Strong Arm" kit:

24mm: E18-4 E28-4 F24-4 F39-6
29mm: E16-4 F40-7 F22-5 F52-8 G33-5 G64-7

The document is titled: MOTOR MATRIX[tm] motor/rocket kit matchup
rev. 12/99
- David Weinshenker 2003

Aerotech delays are cleaning out my rocket supply. I am on the edge of losing all faith in the Aerotech motor matrix. What I am not sure of is if the problem lies in the matrix or the delay accuracies, (or lack there of).

Case in point; Aerotech Strong Arm.

First flight on a F40-7W reload. Extremely long delay, and chute finally opens after much encouragement approximately half way past apogee.

Second flight on a F52-8T reload. Chute opens after rocket drills a 4 inch hole in brother-in-laws hay field. No oil was struck and rocket was destroyed.

Now I have an additional F52-8T and I am concerned about ever using it. I can't afford the rockets lost via the Aerotech bonus delays. Am I doing something wrong? I have read ROL news letters about delay issues of inaccuracy in other Aerotech reloads. I wonder if the problem is more wide spread.
- Larry Zeilmann 2003

A customer of Aerotech should be able to purchase, assemble, and fly there rocket's on engines recommended in their Motor Matrix and have a reasonable expectation of getting it back in one piece. Their Motor Matrix should allow for a reasonable variance in wind and mass, so as to provide a conservative level of protection. Those who wish to fly on the edge can experiment with nonrecomended motors and except the associated risk.

Without the motor, my rocket weighed in at 632 grams and had a CG of 71.75 cm aft of the nose tip. I was flying in less then 10 knots of wind. I am of the belief that this performance criteria should fall well within the acceptable operating envelope. Are my assumptions unrealistic?

The point on using too long of a delay is well drilled home. The only point left for consideration is why the manufacturer continues to publish bad information? The delays used in both cases are the delays specified by the matrix. Newbies to the RMS and mid or high powered rocketry should not have to learn about this through the school of hard knocks.
- Larry Zeilmann 2003

I can only relate my experience; AT Strong Arm built to specifications loaded with a F52-8T. Launched on the vertical in less then 10 kts of wind. Deployment charge occurred after impact. Nothing more I can prove or offer as to why the chute did not deploy at apogee or prior to the rocket being destroyed.
- Larry Zeilmann 2003

Ok folks, here's a quick story, I still gotta e-mail a couple of other folks, including Diane at Aerotech. I had two RMS 24's blow out using reloads from the same batch. The nozzle in both cases left the hardware, spewed the contents, and damaged my rocket....TWICE.
- Thomas Parson 2003

Interesting. I had a D21T literally blow up and destroy the motor end of my son's rocket a while back. I emailed AT and asked them what to do. I retained the remains in case they wanted them. Never heard a word from them. After a couple of months I decided they didn't care about one little motor and rocket so I destroyed the remains. For those who think the delay element burns nice and gently, think again: after separating it from the remains of the core, I lit it on a nice flat concrete surface and lo and behold, orange and white flames shot out 6" from the lit side. When it burned through, another 6" flame shot out the front.
- Pete McClure 2003

Hello everyone, well this is the "opinion" forum so here it goes. I've tried the new A/T two wire igniters twice now, both times the nichrome wire has burned through without igniting the pyrogen(or the motor)!!! Both times it has been at a club launch using 12 volts with plenty of current. This record is actually WORSE than my experience with the copperheads! I didn't think this was possible. Talking to the club prefect, it has apparently happened a few other times with other fliers as well! Has anyone else had simular experiences with the new igniter?
- Blair Clark 2003

Well, the E9 is about 150% of the D12. D12s are up to $10 a pack, so E9s at $15 a pack isn't "unreasonable". It *IS* more expensive than a pack of E18 reloads that have more power and CAN lift those rockets that the E9 won't.
- Bob Kaplow 2003

On the other hand, consider that you need about $120 worth of hardware to fly a 3 motor cluster of E18, while you only need the $15 worth of motors to fly a three cluster of E9. Not to mention that igniting three BP motors is a lot more reliable than igniting three composite reloads...
- Donald Qualls, aka The Silent Observer 2003

Yep, I had a G64 do something very similar. It started out just fine and then appeared to suffer about 75% reduction in thrust. I suspect that something clogged the nozzle. Then it started the loop-de-loop. Post crash inspection showed that the pressure buildup found release in the lower closure & case joint. Total destroyed the motor case and closure. Still have them. It was past the 1 year warranty period and since I have had difficulties in the past to get Aerotech to warranty a 24mm cato and a 54 forward closure blow-by, I figured I was just plain out of luck.
- David Thedens 2003

I think that's a bad move, I think that the flier should make the call whether or not he wants to do electronics.

It's bad enough that AT is selling its new Redline reloads without delays , but now rumor has it that all AT reloads won't have delays included in the reload kit in the future. To me, that sucks. I already have two many packs of delays that I'll never use because I had to buy 5 in order to use 1 and the delays have been redesigned in the meantime to become more relaiable. Thank God that not everyone shares their philosophy of continuously making it more difficult for the consumer to fly reloadable motors. In addition to supplying my own ejection charge and igniter, now I'll have to stockpile up to 18 separate delay kits. Jeez.
- Mark Simpson 2003

I wish that were always the case. I put a G55-5 in my Stovi. 15 seconds past burn out it ejected, at which time the rocket was about 5 feet off the ground. It had enough time to separate. The top section did the gopher bit, digging into the earth and the bottom section hit about 12 inches away taking a truly impressive core sample. Also broke my Olsen M2 which was along just for the ride as a test flight.

I was able to repair the Stovi by replacing the main section of airframe and AT replaced the motor with a new G55-5. Scott Olsen also repaired my altimeter for a very reasonable price. Six months later, I flew the repaired Stovi on the replacement G55-5. Same thing. Ejection at 15 seconds past burnout. Same general condition. Fortunately, no altimeter was in the rocket this time.

I repaired it again, replacing the already replaced airframe and it's still alive.

Neither time did AT offer a replacement rocket. Frankly, I never expected them to. Their warranty, and Estes for that matter only bind them to replacing the rocket if it is their motor that causes damage to one of their rockets.
- Bob Chmara 2002

Nice rocket, nice [AeroTech] kit but it breaks a lot of fins on hard landings.
- Bert Harless 2003

My fins all have broken tips and one cracked at body tube and has been repaired but then again, I built mine really heavy using epoxy instead of the recommended CA. I had a failed ejection once so my nose cone is a bit wrinkled and when I rebuilt it I lengthened it by about 8" and changed the AT baffle design for one more like the one Kaplow has in his .sig at the end of his posts.
- Norman Dziedzic Jr. 2003

We have a couple of these Mantis pads sittin' around collecting dust. They're a little too light to use for anything much bigger than an Initiator.
- Bert Harless 2003

The mantis pad is a waste of plastic. The launch controller isn't worth the incremental price over the Initiator. Unless you can do what I did and get the set for $50 at an HL sale, buy a similar sized rocket and either join a club or buy/make your own pad and controller.
- Bob Kaplow 2003

The AT Mantis pad is a FANTASTIC design....RUINED in plastic. Don't bother with it, do a PVC pad, for about $15-20 and save the headache of the mantis.
- Tom E. Parson 2003

The change is long over-due. I had a Mantis pad and liked the look but Jeez-O-Pete that was the flimsiest and most expensive pad I ever saw. I was especially bent out of shape when I opened the box and found the legs to be "in the white". The box showed this cool yellow with black warning stripe theme that was not part of the deal. I felt gypped. Then I discovered that the black in the photo came from electrical tape.....Jeez! So I painted the legs Chromium Yellow and added my own tape. Viola! it now looked like the box. I took it out, loaded a Mustang on it and pop!, it broke. POS. I've got a quad-pod as well. Damn that thing is near perfect. Cast aluminum and machined steel..a work of art. I also have a Vaughn Brothers pad. Cheaper than the RV pad by almost $100, it is none the less, very functional and highly transportable. It darn near impossible to break as well. On a scale of 1-10 were 10 is the best, I'd rate the RV pad a 9+, the VB pad an 8 and the Mantis a distant 2. If value for the dollar spent were the issue then VB would get a 9, RV would get an 8 and the Mantis would get a . Too bad too because I like most of ATs stuff.
- R. J. Talley, Teacher/James Madison Fellow 2003

Best laid plans of mice and men. This pad was originally the Enertek pad. Then Paul Hans transferred it to Errortrech who has been using it in this crappified state ever since. About 10 years I would estimate. So this "upgrade" seems more like an indication of total customer disghust and shunning, than any particular concern for "customer satisfaction" at errortech. Heck if "customer satisfaction" was really the issue, the moment the issue was identified about 9 years ago they would have recycled all othe old plastic and made new ones then.
- Jerry 2003

I had one for a few years and finally traded it to a club member for $10 or so. I never had the original instructions so I don't know if it warned you about rod whip or the "Mantis Dance".
* The rod whips as the motor ignites and the rocket starts to move. Contributing factors are aluminum rod and the balance of the entire system (including deflector). Solution: partial solution is to upgrade to a 6 foot long steel rod.
* Mantis Dance: When most LMRs ignite and start to move, you get the rod whip but you also get the entire pad tipping and dancing/shuffling sideways!! Solution: Place weights on 2, 3 or 4 legs to hold them down. 1 gallon jugs filled with water work OK and serve as fire extinguishers.

I also had broken plastic ranging from the angle adjustment screw to the leg attach areas. Metallic doublers epoxied on fixed the breaks. Production fix would be to improve the rod and change the legs from hollow aluminum to solid steel. Maybe solid aluminum would work. I know that this will drive up the cost and the shipping cost as well.

Otherwise we can all continue to 'warn' people about the problems AND provide the solutions indicated above if they insist on buying the cool looking pad. It DOES look cool, even if it does not work cool.
- Fred Shecter 2003

I thru the whole darn thing away after it broke twice while I was putting it together. You talk about the pad, but the rod was also a joke - two part aluminum! (anybody else using a rod that's not steel or SS?)

Now I use a quad-pod and a trans-pod (had them for years as RV is now out of business!)

The Mantis pad is a joke... Better plastic won't change the fact that it's a bad design and won't even handle even all the AT birds! I've seen a few take the flight with the bird!

$10 of PVC pipe/couplers, a steel rod, and a flowerpot for a blast defector is a better deal!

The AL rod was part of the problem... The sucker would bend if you looked at it wrong!
- Woody Miller 2003

Will it withstand an I motor, or will it still meltdown?
- Woody Miller 2003

Just thought I would give the update myself, we changed the plastic material for the Mantis Launch Pad to ABS last year to improve the durability. It is much tougher, proved to mold within tolerance (important) and should withstand more abuse than before.

And finally, the fins for the G-Force/ Sumo/ Astrobee-D have also been changed to ABS to resist breakage on hard landings. They withstand cold weather better to.

I would not recommend anything above "g" motors.
- Robert Rosenfield, Mfg Engineer, AeroTech & ISP Inc. 2003

I've had a litany of problems related to AT's poor QC, spanning K550 liners that were almost 1/2" too long, to wrong packaged delays, to defective delay liners to the most recent squishy grains that are full of voids. Maybe my expectations are too high for a company in a niche market, but I don't expect every flight to be an adventure and that's pretty much what it has become. Real QA means never having to say "I'm sorry".
- Mark Simpson 2003

I had a CATO of a J350 in early June, sent in the motor to Aerotech. Mike M. responded with an email he would replace it ASAP. I have yet to see the hardware 2 months later. Some response time!!!! I guess you have to be at LDRS to get fast response from Aerotech.
- Wayne Koskey 2003

I am fairly new at this, but it seems to me that a great many of the failures that I have experienced or witnessed have to do with failures of the delay/ejection charge and/or the forward closure. I am talking about RMS motors. It also occurred to me that electronic (altimeter-controlled) deployment (once you have eliminated "dumb" human errors like failure to arm, using too much BP, setting switches wrong, etc.) is much, much, more reliable.

So, if you go to altimeter-controlled deployment, you should be able to avoid the dreaded "zipper" associated with ill-timed deployment, and if you go with a plugged closure you should have fewer failures associated with forward seal breaches. I know if I had gone this route, I would have had to spend less time on rebuilding and would have several more rockets in my active arsenal.

Forget about motor ejection as a redundant system - it is more likely to CAUSE a failure and loss of your bird than just relying on a well designed and tested altimeter ejection system.

Also with the increased availability of small, light altimeters and the high reliability, low cost, and low mass of the Christmas light "e-matches" (Perfect Flight) altimeter deployment is doable even on many model rockets using the AT 24/40 and 29/40-120 RMS systems.
- Michael Smart 2003

Well, after flying the Big Daddy perfectly on a D12-3, I went back and loaded up an E15-7. I loaded up the crapperhead and hauled it to the pad. I hooked up the igniters and all and waited. When they fired it there was smoke, but no ignition. So I went back and bought some FirstFire igniters, because they had no Jrs.I then modified them (per Tim) to fit, and Don Guzzy (The RSO/LCO dropped the bit of pyrogen down in there. We stuck it in anyways and decided to try, and by gosh it worked!. It was awesome, it flew great, burnout, William started counting, 1 1 thousand, 2 1 thousand, It arcs over, 3 1 thousand, 4 1 thousand, 5 1 thousand, 6 1 thousand, 7 1 thousand, 8 1 thousand, its getting close to the ground, 9 1 thousand, 10 1 thousand, THUD, 11 1 thousand, Ejection!
Well that came a bit late, as the rocket already took a hard lawndart. What could have happened to that motor, is it worth calling AT about and what will they do about it?
- Stephen Corban 2003

I'm glad people are having good luck with replacement's for their bad J-350's. It's to bad I can't say the same. 4 month's and counting since I frist contacted AeroTech about 3 J-350's I bought at NYPower. They told me they would send out the replacement's right after LDRS and then they said Bob Elis would be sending them out soon as they called him. Here I sit waiting for the UPS person to ring my Door bell. I gues I will not have them in time for Three Oaks.
- Dan McCullough 2003

I saw this on the DARS-General group on Yahoo:

> I picked up the motor on Saturday. At that time the slugs selected > were marked for all 38mm WL motors. They then pulled out a special > slug which I assume was from the harder batches and it was drilled > to 1/2 inch. They recommended that this drilled slug be used on the > nozzle end. I also watched them assemble a J350 while I was there. > They pealed a layer of paper off each slug before inserting it into > the liner. Basically I couldn't have gotten the slugs in the liner > without doing it do to the extra width added by the sticker on the > side of the slug. This too could have contributed to > overpressurization issues if people forced these into the liner as > is. They also recommended pulling the igniter out of the motor > about an inch farther than you normally would to allow the motor > to pressure up more slowly. I didn't take their advice on this one.

When you learn all these tricks over a long period of time, it doesn't seem like a big deal, but when I saw it listed all together, well...it doesn't inspire a lot of confidence.
- Doug Sams 2003

As a consumer I want to Know that a given engine will perform with in a close tolerance to a standard.

We all do. But the more testing and retesting that is done, the more it will cost. How much more are you willing to pay for near-perfect reliability?

What puzzles me is how these soft grains got past a simple visual inspection during an entire month of production. If the difference was noticeable to the consumer, it should have been noticeable to the manufacturer. Someone screwed up.
- Ray Dunakin 2003

That really is not an issue here. There are going to be issues that come up. The question is how to take care of them. I have always liked Aerotech but with this, people saying they have been quoted 6 weeks for replacement, that's a bit excessive. They already said they have new loads ready to go, but they also said those are going to LDRS. I'm just glad I had defective Pro38 loads. Because they were willing to break into the LDRS stash and replace what was damaged.

Aerotech basically gave people the finger. "If you are not going to LDRS then we don't care about you. We already have your money so you are going to have to wait so we can get others money at LDRS." Not a good way to keep the customers happy. But I guess they don't realize the monopoly is over.
- Robert DeHate 2003

I suspect that it was noticed. However the QC engineer probably took off his engineer cap, put on his management cap, and said, "It may be OK, let's see how it does in the field." :( You are describing consumer fraud. That is a [allegedly] crime.
- rmr 2003

I think he's suggesting that if an employee quits or goes on holiday, the motors made in their absence must be re-certified.
- Joel 2003

I am suggesting that the reported spongyness of the grains could not have gone unnoticed by inspectors, or even workers and packagers. I made a deliberate reference to the Challenger cato, and I suggest that people do not learn from past mistakes. I'm not suggesting fraud. I am suggesting that rather that have customers pissed at them for not delivering product in time for a schecduled launch, they opted to take the risk that a few customers might be pissed that delivered motors did not perform to cerrtified specs, and in fact some catoed.

This is all just BS musing on my part. I have not flown or seen one of the suspect grains. I am not familiar with thier manufacturing jprocessos, QC procedures, or management practices.

The motor should not be certified to new specs. Rather the process or formula should be adjusted so that motors produced in a different environment perform to the certifed specs of the intended motor(s). It seems obvious that someone screwed the pooch and got it wrong.
- Alan Jones 2003

We welcome more feedback!


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