lost rockets and a reflection on costs

No SU motor is going to have a long enough delay for an M flight. My regular parachute did deploy at 800 feet but immediately shredded as the reocket was going too fast due to lack of drogue.

I would not say this is a regular occurance.

My buddy decided to use motor ejection as backup on a J motor. Blowby ignited the ejection charge early and pretty much destroyed the rocket. This was an older reload before RMS+.

Brian Elfert

Reply to
Brian Elfert
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I am suggesting ADDING small solids as a backup.

At least until the fakeout and ignition issues are resolved for the hybrids. It is possible hybrid flight reliability will always justify a simple pyro delay backup.

Jerry

Reply to
Jerry Irvine

Since many in the group have certain people in their filter, it would be helpful if others would not reply to their comments.

The second M flight failure I witnessed would not have been saved by an AP motor nor a timer as it crashed before either would have been expected to perform. Pushing a button when the human determines it is needed is a true backup. It might not have saved the rocket in the second crash either, but maybe the tank or electronics would have been recovered.

Reply to
Safety First

Use an Estes D12-0, add a stock RDK delay to the back, epoxy around the delay to retain it and use THAT as a backup delay.

Just Tech Jerry

Reply to
Jerry Irvine

Brian, can you tell us more? Did you determine the cause of the failure?

Were you able to determine if the charges fired?

Were the altimeters accelerometers or baro?

Were the altimeters the same brand and model or different?

Had this combination flown successfully prior to this flight?

I have twice had the problem of the apogee charge firing but the rocket not separating. I solved that problem by using a sufficiently sized charge to ensure separation no matter what deformation might occur during flight that could cause the sections to not separate, and designing the system to survive that charge size.

Dean

Reply to
Dean

Which they is that?

Wouldn't a baro system properly sense apogee, even at 800 feet?

Maybe the entire solution is to activate your electronics by a pull switch at liftoff rather than sensing something.

Jerry

Reply to
Jerry Irvine

Huh? Launch detect on an underpowered Hybrid is no different than on an underpowered solid.

The oscillation issue on some hybrids should not be a concern if you choose your altimeter appropriately.

The High Voltage issue used with some hybrids does require careful physical design to keep sensitive electronics away from the HV.

My experience with hybrids reliability is that once they are lit they are just as reliable as AP motors. Partial fills is the biggest problem I've seen, and that usually tapers off with experience.

Reply to
Alex Mericas

No, not really.

We had to switch Hypertech M motors at the last minute due to a missing O ring. The tank on the second motor didn't fit very well. We had to hammer the motor in which probably didn't help things at all.

I don't recall for sure. Everything was pretty well crunched. I dimly recall that the charges didn't fire.

Baro.

Missileworks RRC2 and an Adept deployment controller.

Yes, they both flew with a Hypertech M in a different rocket the year before.

I had this rocket not seperate at apogee once, but was due to a missing chute protecter. I used cellulose wadding instead and the wadding basically absorbed the ejection gases. Luckily, the rocket did a flat spin until the main deployed.

Brian Elfert

Reply to
Brian Elfert

Ask your wife. She'll know right down to the last penny

Reply to
Dodo

I had that happen on my first mid-power rocket Last December. I had previously only launched Estes-type models, but bought and built a LOC Starburst. Since this would be the biggest motor I'd used to that point I also bought a PerfectFlite alt in it to see how high it would go. On its maiden voyage it had a beautiful launch and flight, deployment was smooth, and we watched it land...more than half a mile away. That was my first launch that day, and I spent the next 2-3 hours in 30 degree weather looking for it(and seemingly finding every damn hidden puddle in the area). No joy. So between the cost of the kit and the alt, I probably lost about $130 worth of stuff. Nowhere

*near* what some of you guys spend, but a pisser for someone who hadn't spent more than about $20 on a bird before.

Eldred

Reply to
Eldred Pickett

I agree with you and wanted to add that some electronics allow you to use a break wire as a trigger. If that feature is available, it would be good to use it on the type of flights being discussed.

Reply to
Phil Stein

I just lost the top stage of a plans-built Apogee II - 2 C's to 2600 feet. It hooked over a lot more than I would have expected. The high clouds kept the sun away so the mylar streamer didn't sparkle. (Assuming it opened). I expected to lose it on that one. (I got the Commanche 3 back after I launched it on D-C-C, so I was still happy at the end of the day).

I'd put the total loss at about $5 because of the clear payload bay. It's nice building modrocs from discount-bin acquired designers specials and a chunk-of-balsa-from-a-friend, home-turned nosecone.

My son wonders why I haven't been getting a Level 1 rocket ready. I tell him that it's because I haven't finished learning everything I can from the little ones (half truth). I already spend enough on model sailplanes.

Personally, after seeing the cost of many of the Level 1 and Level 2 rockets, I don't think the rockets or the electronics are that bad. A nice model sailplane is easily going to run you $500 or more after you get all the servos, receiver, and battery pack into it. The biggest thing is feeding the beasts. I have an easier time getting a hundred bucks worth of electronics for the sailplanes than having to get the motors every time I want to launch:

"I thought you have 50 motors downstairs" "Yes, but there not the right ones"

Reply to
Thomas Koszuta

Can't remember

Kurt Savegnago

Dementia means having to meet somebody new every day!

Reply to
Kurt

Hi,

A beeper might have helped you with this one. Been experimenting with them and had a Super Nova Payloader go in some tall grass on an E30-7. Chased the model and saw it miss the treeline as I had a good line of sight fix. I picked up the beeper but thought I would keep walking to where I thought the model was. I stopped where I thought it went done and the beeper suggested it was off to the left. I turned to the left and followed the sound and found that the model was 60' from where I thought it was. If I didn't have the beeper on board, it might have taken me a long time to find. They are mandatory for me if I am uncertain as to how a model will behave.

Kurt

Reply to
Kurt

Here's something I wrote about beepers.

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Hope it helps

Reply to
Phil Stein

[My answers based on the assumption that Brian is referring to the launch I witnessed]

I disagree. I believe the electronics were damaged on a previous flight, as I recall at least one altimeter had black powder residue on it.

While it can be hard on the motor, I don't think it made any difference. Motor performance was optimal on the way up, as I recall.

One of the charges fired just as it was going beyond the hill, on the way down, which means the altimeters armed. Not sure which one, though; the rocket was moving WAY too fast at that point for it to be saved by any recovery system.

-Kevin

Reply to
Kevin Trojanowski

The residue was from a leaky electronics bay. The one with residue hada been sent to Missile Works for repair so it had been fully tested by the manufacturer. (I had broke off a terminal at one point.)

I think pounding the motor in jarred something loose in the ejection system.

Brian Elfert

Reply to
Brian Elfert

Okay, I didn't know you had sent it in to MissleWorks for service. I'm sure Jim checked it out thoroughly before returning it to you.

If that's the case, I'd say there was a bad connection already that may have failed even under thrust.

-Kevin

Reply to
Kevin Trojanowski

No "pounding" allowed on rockets.

Reply to
Jerry Irvine

Electronically.

Reply to
Jerry Irvine

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