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For reference, I ended up using .5g for both charges on mine but I have three 2-56 shear pins at the separation points.
Madcow Mini DX3
- Thread starter Caley
- Start date
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Hmmm, I will try the low powder charges to see if they work. If not, I will up things a bit to see what happens.
I've another question, this on e-matches. I just finished making 80 of them from a kit. Needless to say, what I observed in the video, and what happened with mine, aren't the same. In the video, they ignited an e-match with a AA penlight battery. I tried that, and nothing. I went to a 9 volt battery, and one worked. The problem is I cannot fit a 9 volt battery in my EBAY. I purchased an Altus Metrum 400mAH 3.7 volt Lipo battery. This powers their Sual deployment altimeters.
What I wish to know is, does this single cell lipo push enough amperage to set off an e-match?
And another question is, if so, will the battery withstand the surge in current, as there is no regulator circuit board. I'd hate to see the chute deploy, only to see a trail of fire because the battery was overdrawn during the ejection charge phase..
Current status of the Mini DX3 is it still needs to be painted. I am still waiting for a day that has calm air. So far we have had some pretty nasty winds in the area.
I've another question, this on e-matches. I just finished making 80 of them from a kit. Needless to say, what I observed in the video, and what happened with mine, aren't the same. In the video, they ignited an e-match with a AA penlight battery. I tried that, and nothing. I went to a 9 volt battery, and one worked. The problem is I cannot fit a 9 volt battery in my EBAY. I purchased an Altus Metrum 400mAH 3.7 volt Lipo battery. This powers their Sual deployment altimeters.
What I wish to know is, does this single cell lipo push enough amperage to set off an e-match?
And another question is, if so, will the battery withstand the surge in current, as there is no regulator circuit board. I'd hate to see the chute deploy, only to see a trail of fire because the battery was overdrawn during the ejection charge phase..
Current status of the Mini DX3 is it still needs to be painted. I am still waiting for a day that has calm air. So far we have had some pretty nasty winds in the area.
rharshberger
Well-Known Member
There are many on this forum who have tried the ematch kits and with few exceptions most have chosen commercial ematches such as the MJG Firewires ( legal to purchase w/o a LEUP). Homemade ematches seem to have reliability issues. Many of us do make motor igniters though.
Rich, Thanks, I have seen those, and more than likely will end up getting a package of them. But I can at least use the ones I made for ground testing. It seems I just need to use the 9V battery to get them to ignite. The kit I purchased was from MJG. The problem probably wasn't the kit in itself, as it required you to make all 80 in one sitting. Definitely an all day project, and a messy one at that. It does seem that the wires they provided can be cleaned up and reused. I did that, and both ignited with the 9V battery.
It's been a while since I posted anything here. For the past three months the winds have kept me grounded. So I haven't had a chance to fly the Mini DX3, or my Blobbo.
As things were, I was having difficulty finding motors to fly them. I had purchased several with the Blobbo, only to find that they didn't have enough spunk to get the model flying. Yesterday, despite the wind, I went to the ROC meet where one of the vendors who sold me the items. I explained that the recommended motors would not work, and I was invited to pick another pair that would do the job. The two packs of ESTES motors were taken in trade for those new more powerful motors. That is really nice of the vendor
As for the DX3, I've decided the first flight will be with only one deployment done by the motor ejection charge. I just want one flight that is hopefully successful, before getting fancy with dual deploy. Hopefully the ROC gathering next month at the Lucerne Dry Lake Bed will not be blown away. I think I can handle the heat for one flight in the morning before packing up. Yesterday had winds so bad that at times visibility was only a few car lengths
And I made a joke about my being there was why the wind was there. Guess what. From what I observed, the winds abated when I left. And this morning in 29Palms the winds were calm. I just know that if I had packed up, and headed back to the launch site, the winds would have come back. I think I am jinxed. Six months, and so far not one flight for one reason or another.
As things were, I was having difficulty finding motors to fly them. I had purchased several with the Blobbo, only to find that they didn't have enough spunk to get the model flying. Yesterday, despite the wind, I went to the ROC meet where one of the vendors who sold me the items. I explained that the recommended motors would not work, and I was invited to pick another pair that would do the job. The two packs of ESTES motors were taken in trade for those new more powerful motors. That is really nice of the vendor
As for the DX3, I've decided the first flight will be with only one deployment done by the motor ejection charge. I just want one flight that is hopefully successful, before getting fancy with dual deploy. Hopefully the ROC gathering next month at the Lucerne Dry Lake Bed will not be blown away. I think I can handle the heat for one flight in the morning before packing up. Yesterday had winds so bad that at times visibility was only a few car lengths
And I made a joke about my being there was why the wind was there. Guess what. From what I observed, the winds abated when I left. And this morning in 29Palms the winds were calm. I just know that if I had packed up, and headed back to the launch site, the winds would have come back. I think I am jinxed. Six months, and so far not one flight for one reason or another.
As I said before, it has been quite some time since I posted, but this time some good news.
As I started mentioning my Stretch Blobbo here, I've decided that I might as well let you all know that it has finally flown. It took me nearly six months to get a day that wasn't either raining or blowing over 20mph, but the flights, two of them finally happened. I used an Aerotech E-30T7 on both flights. First flight was almost perfect. I got just a tiny bend at the top of the body tube where the shock cord tried to create a zipper. But the ejection charge basically occurred at apogee, so no damage. Most of my damage is cosmetic because of the surface the rocket lands on, Lucerne Dry Lake Bed, which is rock hard.
Two problems occurred. One was that I discovered that my nylon parachute got singed. Fix is to pack the dog barf, instead of leaving it fluffed. On second flight there was no problem. Second problem was that my knot up at the eyelet screw was not a good one, and as the model descended, the shock cord kept slipping with the nose cone slowly becoming the lowest part when it impacted the ground. Fix was just to loop a knot over what I had. On second flight, no slippage.
So, it was a total success on the two flights, with just minor problems, that were easily fixed. Both ejection charges went off at apogee, something I was really worried about.
I think I mentioned before that I had installed a lot of nose weight to put the CG well ahead of the CP. It turns out that I was informed that these short rockets are designed differently, and that the CG isn't needed as far forward. I was told that something around a 30 percent body diameter difference should work fine, and it did. The flights were arrow straight, coming off the launch rail perfectly. Unlike many rockets I saw fly this morning, mine did not waver or tilt off of vertical. Anyway, the change in nose weight was accomplished by my purchasing an eyelet bolt with lock nut and two washers. I also added one ounce of lead weight. What I did was smash a one ounce fishing weight into an oval, drill a hole in the center, then used the washer and lock nut to secure things to the 1/4 inch ply. I had cut off the plastic loop on the nose cone. Actually I cut off the entire bottom of the nose cone, then inserted basswood block hard points inside, then screwed the 1/4 inch thick ply to those hard points. This allows me to remove nose weight if I decide to put some kind of payload in the nose. I would have preferred to have had a 1/4 inch ply ring glued to the inside, but I don't have the skill to create such a thing. It was difficult enough making the 1/4 circular nose plug.
I have a couple of Aerotech E-44T8 motors I will use on my next two flights. I believe that the rocket will fly just a bit higher with this motor.
Once I have those two flights in, I will then graduate to my Mascow Mini DX-3 for about four flights. I could not get a dual deployment set up with two altimeters, so I decided to use the motor ejection charge as the first step. I purchased a Jolly Logic Chute Release, and have ground tested it, with good results. So, this is going to be my dual deployment setup. If all goes well on the four flights with the Mini DX-3, then I will order a larger kit to graduate to my Level One model.
So, so far, so good with my come back in model rocketry. Just wished that it hadn't been so hot. It was near 100F when I left around 10AM. I'm not a heat person
As I started mentioning my Stretch Blobbo here, I've decided that I might as well let you all know that it has finally flown. It took me nearly six months to get a day that wasn't either raining or blowing over 20mph, but the flights, two of them finally happened. I used an Aerotech E-30T7 on both flights. First flight was almost perfect. I got just a tiny bend at the top of the body tube where the shock cord tried to create a zipper. But the ejection charge basically occurred at apogee, so no damage. Most of my damage is cosmetic because of the surface the rocket lands on, Lucerne Dry Lake Bed, which is rock hard.
Two problems occurred. One was that I discovered that my nylon parachute got singed. Fix is to pack the dog barf, instead of leaving it fluffed. On second flight there was no problem. Second problem was that my knot up at the eyelet screw was not a good one, and as the model descended, the shock cord kept slipping with the nose cone slowly becoming the lowest part when it impacted the ground. Fix was just to loop a knot over what I had. On second flight, no slippage.
So, it was a total success on the two flights, with just minor problems, that were easily fixed. Both ejection charges went off at apogee, something I was really worried about.
I think I mentioned before that I had installed a lot of nose weight to put the CG well ahead of the CP. It turns out that I was informed that these short rockets are designed differently, and that the CG isn't needed as far forward. I was told that something around a 30 percent body diameter difference should work fine, and it did. The flights were arrow straight, coming off the launch rail perfectly. Unlike many rockets I saw fly this morning, mine did not waver or tilt off of vertical. Anyway, the change in nose weight was accomplished by my purchasing an eyelet bolt with lock nut and two washers. I also added one ounce of lead weight. What I did was smash a one ounce fishing weight into an oval, drill a hole in the center, then used the washer and lock nut to secure things to the 1/4 inch ply. I had cut off the plastic loop on the nose cone. Actually I cut off the entire bottom of the nose cone, then inserted basswood block hard points inside, then screwed the 1/4 inch thick ply to those hard points. This allows me to remove nose weight if I decide to put some kind of payload in the nose. I would have preferred to have had a 1/4 inch ply ring glued to the inside, but I don't have the skill to create such a thing. It was difficult enough making the 1/4 circular nose plug.
I have a couple of Aerotech E-44T8 motors I will use on my next two flights. I believe that the rocket will fly just a bit higher with this motor.
Once I have those two flights in, I will then graduate to my Mascow Mini DX-3 for about four flights. I could not get a dual deployment set up with two altimeters, so I decided to use the motor ejection charge as the first step. I purchased a Jolly Logic Chute Release, and have ground tested it, with good results. So, this is going to be my dual deployment setup. If all goes well on the four flights with the Mini DX-3, then I will order a larger kit to graduate to my Level One model.
So, so far, so good with my come back in model rocketry. Just wished that it hadn't been so hot. It was near 100F when I left around 10AM. I'm not a heat person
Nytrunner
Pop lugs, not drugs
Sounds like a good learning flight! Great to hear that you've got to try out some new techniques.
Im not sure I've ever heard of an E44. Are you sure it isn't an F?
Also, did someone tell you you needed to have two altimeters for a dual deployment setup? Two is recommended for redundancy, but one can work as well.
Im not sure I've ever heard of an E44. Are you sure it isn't an F?
Also, did someone tell you you needed to have two altimeters for a dual deployment setup? Two is recommended for redundancy, but one can work as well.
Yes, that was a typo. The motors are F-44T8. As for dual deployment for the Mini, I could not get things set up in the small body. I finally just gave up. As it is, the JL Chute Release is a tight fit, but easier than trying to do the dual deployment with the EBAY setup. It's good I have the Chute Release, as it gives me more recovery options.
Nytrunner
Pop lugs, not drugs
Absolutely right about the chute release. It's friggin amazing for getting motor deploy rockets back from higher up.
Definitely do a blow test to make sure the release/chute bundle will slide out of your tube with little difficulty.
Definitely do a blow test to make sure the release/chute bundle will slide out of your tube with little difficulty.
