Mac Performance 3" Black Fly 38mm L1 build

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Ordered motor. I decided to do first my l1 attempt on a CTI H152bs. This fly Sims to 2347ft on the H152 with 51 ft/s off the rod. I don't think I will have a jlcr ordered in time. But I expect that as long as the weather cooperates and we have a May launch I am on track to get it there and in the air without a chute release.
 
Well no pics today for the work that was done, i am finishing up the nose cone and getting all the recovery stuff setup. once the epoxy is cured on the coupler i will weigh it and get the cg before epoxying the coupler into the nose cone to make sure it does not need more weight. I threaded the Pro-Tec cover over the lower shock cord and unpacked the chute and rest of my parts. still waiting on motors to arrive. I will start sanding the fillets tomorrow. I still have not decided what i want to do for paint so i may just leave it completely naked and decal it. I am on track for a launch May 6 as long as weather is good.

This last week i ordered some more stuff from Mike over at Mac Performance, so another build thread may be imminent. I also have started designing 2 of my own Rockets that i plan to turn at least one of into a build in the very near future.
 
Ok! We have measurements pre paint! And I think I am very satisfied with how the sim is looking numbers wise. I am feeling comfortable about the nose weight and am thinking I'm good to epoxy the nose cone coupler in place. Thoughts?nomotorfinal1.jpgmotorfinal1.jpg
 
Ok! We have final measurements pre paint! And I think I am solid with the numbers. Thoughts?View attachment 343440View attachment 343441

Tough to read the numbers for me but it looks like a 1.5 or 1.6 Cal with a sim to 2,000+ AGL. Have you figured out the TTW ratio? Have you done a stability vs. time analysis? BTW did you consider the CTI H225 White Thunder? Now that you have dialed in your OR file if you post it I wouldn't mind having a look at the sims.

Just remember relatively short stubby rockets are inherently unstable and typically need nose-weight. The last thing you want is for your L1 cert flight to be doing cartwheels off the rail.
 
Tough to read the numbers for me but it looks like a 1.5 or 1.6 Cal with a sim to 2,000+ AGL. Have you figured out the TTW ratio? Have you done a stability vs. time analysis? BTW did you consider the CTI H225 White Thunder? Now that you have dialed in your OR file if you post it I wouldn't mind having a look at the sims.

Just remember relatively short stubby rockets are inherently unstable and typically need nose-weight. The last thing you want is for your L1 cert flight to be doing cartwheels off the rail.

Absolutely. if i am being honest i am still trying to figure out how to calculate that. I have been focused on getting above 45ft/s off the rod. I did plot the stability, and to my EXTREMELY knowledgeable eyes it looks OK? I procured a weighted nose cone tip from gfunk. I am hoping with that plus the extra BT length i will combat the stability issues of the stubbier versions. Please take a gander and let me know what you think; Here is the file:

View attachment 3 Inch Black Flyv1.rkt
 
Absolutely. if i am being honest i am still trying to figure out how to calculate that. I have been focused on getting above 45ft/s off the rod. I did plot the stability, and to my EXTREMELY knowledgeable eyes it looks OK? I procured a weighted nose cone tip from gfunk. I am hoping with that plus the extra BT length i will combat the stability issues of the stubbier versions. Please take a gander and let me know what you think; Here is the file:

View attachment 343447

Just a quick verification. You have mass and CG override on for the whole rocket, is this based on actual numbers specific to your build and was this with the rocket loaded and prepped for flight including your recovery gear, but excluding the motor? Also what is the recovery gear and config that you are considering?
 
Just a quick verification. You have mass and CG override on for the whole rocket, is this based on actual numbers specific to your build and was this with the rocket loaded and prepped for flight including your recovery gear, but excluding the motor? Also what is the recovery gear and config that you are considering?

The measurements are specific to my build with the rocket loaded and prepped for flight excluding the motor. Recovery wise i am using a 3' Rocketman Chute, 20ft harness, and 9x9 chute protector.
 
The measurements are specific to my build with the rocket loaded and prepped for flight excluding the motor. Recovery wise i am using a 3' Rocketman Chute, 20ft harness, and 9x9 chute protector.

Using your sim with your manual CG and mass below are some sim results using the H152BS vs the H225WT. They sim to 50' within each other with eh H152 having a slight edge, however because the H225 is higher thrust motor it is a more stable flight. See the stability graphs below. BTW 11 seconds is the optimal delay.

H152BT:
Screen Shot 2018-04-26 at 10.58.36 PM.jpg

H225WT:
Screen Shot 2018-04-26 at 10.59.31 PM.jpg
 
Using your sim with your manual CG and mass below are some sim results using the H152BS vs the H225WT. They sim to 50' within each other with eh H152 having a slight edge, however because the H225 is higher thrust motor it is a more stable flight. See the stability graphs below. BTW 11 seconds is the optimal delay.

Thank you for checking that out. I actually had already ordered the h152 last week. Being delivered tomorrow. The wind forcast for this coming weekend looks really calm, but it's gonna be HOT.
 
Well some bad news for this one, This weekend launch of my Fly will not be happening, I may try to attend another launch next month further away, but if not this will give me the chance to get all my paint etc finished properly before its (likely) first launch in October when our season opens again.
 
Well some bad news for this one, This weekend launch of my Fly will not be happening, I may try to attend another launch next month further away, but if not this will give me the chance to get all my paint etc finished properly before its (likely) first launch in October when our season opens again.

So no naked fly then...yay! Well at least that should give you a chance to review some other 3" Fly post flight results and review your choices.
 
Very nice! She did a little correction, but she never looked back, and she has earned her paint job.

You might want to go up one size on the chute, or not. From the video, the decent on main looked aggressive. If you have a JLCR, then go up at least one chute size and stick an I345 in there. You may want to invest in a tracker, if you don't already have one.
 
Very nice! She did a little correction, but she never looked back, and she has earned her paint job.

You might want to go up one size on the chute, or not. From the video, the decent on main looked aggressive. If you have a JLCR, then go up at least one chute size and stick an I345 in there. You may want to invest in a tracker, if you don't already have one.

Yeah she came down at a good trot! I definitely plan to go higher next month with this fly and my hyper 54 [emoji48] it will be jlcr for sure, still debating on bigger chute
 
Yeah she came down at a good trot! I definitely plan to go higher next month with this fly and my hyper 54 [emoji48] it will be jlcr for sure, still debating on bigger chute
Does the chute pack well, or is it tight? If you move to a higher CD rated chute, like a Fruitychute Iris Ultra Compact, with a 2.2 CD, you will get the performance of a chute one or two sizes up.
 
Very nice! She did a little correction, but she never looked back, and she has earned her paint job.

You might want to go up one size on the chute, or not. From the video, the decent on main looked aggressive. If you have a JLCR, then go up at least one chute size and stick an I345 in there. You may want to invest in a tracker, if you don't already have one.
What was your rate of descent?
 
Does the chute pack well, or is it tight? If you move to a higher CD rated chute, like a Fruitychute Iris Ultra Compact, with a 2.2 CD, you will get the performance of a chute one or two sizes up.

I think it’s about a perfect fit packing wise. I will definitely check that one out. According to OR it should have come in 17.7 FPS or so
 
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