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jqavins

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These are the motors that seem to work, although two (C11 and D20W) are marginal. I don't know why it's showing higher rod speed for the C18 vs. the D20.
How long does it take to clear the rod with each motor. The D20 will give it a much better kick in the first, oh, somewhere around 20 ms, but after about 50 ms the C18 has higher thrust. By 200-ish ms there probably is more area under the C18's curve (impulse) than under the D20's.
1610040646926.png
I'd also be interested in the time to rod exit for the D12 and D16. The D16 has higher thrust until about 160 ms, and the D12, and it looks like the D12's impulse might catch up around 300-ish ms.
1610041125443.png
 

jbrracer

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How long does it take to clear the rod with each motor. The D20 will give it a much better kick in the first, oh, somewhere around 20 ms, but after about 50 ms the C18 has higher thrust. By 200-ish ms there probably is more area under the C18's curve (impulse) than under the D20's.
View attachment 445656
I'd also be interested in the time to rod exit for the D12 and D16. The D16 has higher thrust until about 160 ms, and the D12, and it looks like the D12's impulse might catch up around 300-ish ms.
View attachment 445657
your post are awesome. Data driven backed up with visuals i applaud you and appreciate your dedication to math based solutions rather than experience. I’m not implying that you don’t have experience although
 

MikeyDSlagle

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A motor hook is lightest of all.
Yes. I may possibly have one here somewhere,
Speaking for myself, I won't be participating so I only check this thread occasionally. Saw a "final" ORK and was curious to check it out.

Regarding the rocket: I certainly wouldn't shorten it. It'll reduce weight a bit but also reduce stability, which is already marginal.

Regarding the motors: it would useful IMHO, when truly "final", to include only motors/delays in the ORK that are believed to work well. That is most useful info for the flyer.

Regarding the launch rod: Personally I wouldn't fly this rocket on less than a 48" long 3/16" rod. To get a decent rod speed with 36" rod, you need a much higher thrust motor, which is likely to be a bad choice for that very same flyer who lacks a proper launch rod.
I agree on all points. Sorry for the confusion in the name.

Final file that will ride along on the thumbdrive will have only the "best" motors. Flyers will be able to save it and run their own sims, but the core sim will be there for us to use.
 

jqavins

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your post are awesome. Data driven backed up with visuals i applaud you and appreciate your dedication to math based solutions rather than experience. I’m not implying that you don’t have experience although
Aw, shucks. :)
 

MikeyDSlagle

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How long does it take to clear the rod with each motor. The D20 will give it a much better kick in the first, oh, somewhere around 20 ms, but after about 50 ms the C18 has higher thrust. By 200-ish ms there probably is more area under the C18's curve (impulse) than under the D20's.
View attachment 445656
I'd also be interested in the time to rod exit for the D12 and D16. The D16 has higher thrust until about 160 ms, and the D12, and it looks like the D12's impulse might catch up around 300-ish ms.
View attachment 445657
According to OR from a 32" rail, time of clearance:
D16 - 0.205 seconds
D12 - 0.256 seconds
C18 - 0.179 seconds
D20 - 0.15 seconds

When you plot the flight, look at the right side "Flight Events" and you can choose rod clearance. Make sure you have a value vs time and it will appear as a dotted line on the graph. Then you'll need to zoom way in to see the time stamp.

see here.jpg

I've been trying to optimize the sim a bit. I added in the Estes retainer and the added mass actually increased speed off the rail. I must be finding the sweet spot of anomalies because that isn't the first weird result I've seen. Sweeping the wings will shave about half the weight from the fins. I can trim the tabs as well. Added in the engine block, FlightSketch Mini in case, Chute, harness, nomex, retainer, and 24-18 adapter. I sat down an weighed every item again. They hadn't changed. LOL. But my ring and MMT estimates were off. I fully expect the fins to have a different than OR is calculating but it wont be that much difference.

Just tossing it out there for those who may care, an Estes Baby Bertha nose cone fits this Mach1 glass perfectly.

Putting the FlightSketch in the nose, stretching the recovery gear and sweeping the fins and trimming the MMT will get it to a dry weight of 5.8 oz to 6.4 oz with a dry stability margin of .995 to 1.53 depending on how extreme we decide to go with the fins, and with the adapter for the 18mm flights, which weighs .37 oz. I have a version with larger lightning cuts but I don't see that small amount making much of a difference and it may weaken the piece to much. Even ditching the Estes retainer in favor of an engine hook won't make that much of a difference where we need it.

Here are the three I am looking at now. I can cut the fins down to any of these three. I had originally planned on trimming the fins to something like Wander 3 but decided to go less extreme and keep them close to the original. Turns out that wasn't the answer, the big fins were holding us back.
Wander 1.jpgWander 3.jpgWander 5.jpg

And their respective sims will show up somewhere. They don't populate correctly when I put pictures in the post.
For stability and weight, #3 gives the best results. I am leaning ever so slightly toward #1 but I want to hear what others think.

Also wanna hear thoughts (durability, ease of use, so on) on the Estes retainer (.27 oz) vs the engine hook which will not weigh on my scale. Going with the hook helps with stability but the mass saved doesn't really help with exit velocity. I had a regular length Estes hook but must have dropped it between my shed and the house. So I had to settle for the longer one. Maybe the short one will turn up but it's doubtful.

Remember when running the sims delete the mass object "Adapter" or simply set it to 0 mass when running the 24mm motors; and adjust the rail/rod length to match your equipment.

Ya'll play with em and see what you think.

And by the way. I'm officially naming it "The Wanderer". Those who fly it will be Hosts.
 

Tobor

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I was just looking at your OR file #3 and noticed that the MMT is not sized correctly for 24mm motors like the Estes D12 and AT 24/40. ID should equal 0.945" but the Wanderer's MMT ID is 0.915".

Just thought you should know.
 
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Sooner Boomer

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Don't forget the launch lugs when you actually build it. Otherwise we'll all laugh and point. Actually, we'll just nod understandingly. Those that haven't forgotten them just haven't forgotten *yet*!

Oh, and a serious suggestion; put large dia. lugs on. Or maybe two sets, large and small. SEVERAL times I've been at a club launch and nobody brought a small rod. I only fly mod-roc stuff so I've learned to think ahead. (and bring spare, large lugs and CA or gorilla tape...)
 

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--- ADDED ---
I'll go ahead and take the reigns on this and make this the official sign up thread. Tag me in this thread with @MikeyDSlagle and say that you are in. Then message me with your address. This will help me keep the participants in order.
I forgot to join in on this after the original discussion in the other thread. I'm in. Sending address now.
 

rdrown

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Final file that will ride along on the thumbdrive will have only the "best" motors. Flyers will be able to save it and run their own sims, but the core sim will be there for us to use.
Is it possible to have the ORK file AND a file for Rocksim? I do not have Open Rocket, but I do have Rocksim.
 

MikeyDSlagle

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I was just looking at your OR file #3 and noticed that the MMT is not sized correctly for 24mm motors like the Estes D12 and AT 24/40. ID should equal 0.945" but the Wanderer's MMT ID is 0.915".

Just thought you should know.
Thanks. If that's the only discrepancy yall find I'll be surprised. I used the file from the website and modified it, should've known better. But it had me checking the airframe, which turned out to be off as well. And while the values on the MMT don't affect stability (mass and length are correct) the OD of the airframe did affect it. The files were updated. I took out the adapter, I can do a lighter version.

Don't forget the launch lugs when you actually build it. Otherwise we'll all laugh and point. Actually, we'll just nod understandingly. Those that haven't forgotten them just haven't forgotten *yet*!

Oh, and a serious suggestion; put large dia. lugs on. Or maybe two sets, large and small. SEVERAL times I've been at a club launch and nobody brought a small rod. I only fly mod-roc stuff so I've learned to think ahead. (and bring spare, large lugs and CA or gorilla tape...)
😀 I've had to install guides on the field before myself, so yeah it happens. I have some 1/8" printed to use, the idea being they can be replaced when damaged. I found my 3/16" rod so now I can do that size as well. But honesty how often are lugs damaged? I found a baggie with 1/8" and 3/16" lugs so I am probably going that route. And it'll have guides for rails as well.
 

MikeyDSlagle

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I forgot to join in on this after the original discussion in the other thread. I'm in. Sending address now.
Got ya. Welcome aboard.

Is it possible to have the ORK file AND a file for Rocksim? I do not have Open Rocket, but I do have Rocksim.
OR won't save as a Rocksim file and I don't have Rocksim. I don't know maybe you can simply change the .ork extension to ... well whatever Rocksim uses. If someone has both versions maybe they can help out.
 

neil_w

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😀 I've had to install guides on the field before myself, so yeah it happens. I have some 1/8" printed to use, the idea being they can be replaced when damaged. I found my 3/16" rod so now I can do that size as well. But honesty how often are lugs damaged? I found a baggie with 1/8" and 3/16" lugs so I am probably going that route. And it'll have guides for rails as well.
Not sure if you're talking about actually putting 1/8" lugs on this rocket.... but 1/8" lugs should not come anywhere near this rocket. Should be 3/16". Having buttons on the other side is good as well of course.
OR won't save as a Rocksim file and I don't have Rocksim. I don't know maybe you can simply change the .ork extension to ... well whatever Rocksim uses. If someone has both versions maybe they can help out.
OR can save as Rocksim, using the Save As... dialog. However, I'm not sure if *everything* gets carried over; certainly some things do not import perfectly when you read RKT files into OR. Motor selections, in particular. Someone with Rocksim should verify and do cleanup on the file afterwards.
 

Tobor

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OR won't save as a Rocksim file and I don't have Rocksim. I don't know maybe you can simply change the .ork extension to ... well whatever Rocksim uses. If someone has both versions maybe they can help out.
Darn it! Neil beat me to it...
 

jqavins

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According to OR from a 32" rail, time of clearance:
D16 - 0.205 seconds
D12 - 0.256 seconds
C18 - 0.179 seconds
D20 - 0.15 seconds
Hmm. Even without computing the area under curves, it should be right that shorter rail exit time means higher rail exit speed. The exit times fall exactly in line with the average thrust numbers. Contrary to what Neil found. Weird.

[T]he adapter for the 18mm flights... weighs .37 oz.
Youch, that's heavy. 0.37 oz (10.5 g, the mass of 2 US nickles) doesn't sound like much to an HPR guy, but in the LPR world it can mean quit a bit, especially when it's at the aft end. The adapter won't be facing the kind of abuse that the exterior components will, so it can be made very light out of cardboard. All it takes is a small piece of BT-20, an engine block, two 50 to 20 centering rings (either balsa or doubled up card stock) and an engine hook. I made one a while ago that hardly weighs anything.
Even ditching the Estes retainer in favor of an engine hook won't make that much of a difference where we need it.
Below you say is 0.27 oz. Again, it's trivial for HPR, but not for LPR. Small yes, but not trivial.
Also wanna hear thoughts (durability, ease of use, so on) on the Estes retainer (.27 oz) vs the engine hook which will not weigh on my scale.
KISS. The Estes retainer isn't hard to use, but don't add unnecessary complexity or mass. Squeeze out weight. Squeeze extra hard when it's aft end weight.

In the same vane, I'd go with the smallest fins that give you at least 1.0 calibers static stability margin when loaded with the heaviest candidate engine.
 

MikeyDSlagle

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When I would try to "save as" RKT in the past it never carried over my changes, sims or what not, so I quit trying. Maybe it works now, I can try when I get home.

@neil_w
Thanks for the insight. I'll scratch the 1/8" lugs. They were proof of concept for larger ones that I couldn't find my rod to verify fit. But now that I have some true blue 3/16" guides I'll likely be using those rather than print some. If they get damaged it should be simple to remove and install new ones.

I fly from rails and my daughter's smaller stuff uses the 1/8" rod. I haven't scratch built anything this small...ever and my Big Daddy is the only rocket I have with 3/16" guides, but it also has buttons so it always flies from a rail.

@jqavins
I understand completely. Thanks for the input.
The motors that will need the adapter, C18 and D20, pack more punch than some of their big brothers and the absence of the retainer and mass of the adapter doesn't affect the stability or rail exit enough to make much of a difference, 1 FPS or so. I can go lighter on the adapter without a doubt. But you're right, I'm looking at it from an HPR point of view where an ounce here or there doesn't much matter and I don't adapt down, I just get a bigger motor.

I don't think I can squeeze out 1 CAL for the E20 or E30. But I wouldn't hesitate to fly either of those at .7 or so. I haven't been able to track down the local guy for permission to use his field so I may have to settle for the C11 and C18 in my yard. I had intended to fly it on a few motors with and without an adapter before sending it on it's way, to check it's performance, but without that field I won't be able to.

@tcblightning
Welcome to the party, can't edit the list but I got ya.
 

MikeyDSlagle

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For those who are looking for the sims.
I posted three in post #125. I took them down to replace with the updated ones, guess my upload didn't take. I don't function well at 5AM. I'll put them back up when I get home. Apologies.
 

MikeyDSlagle

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Updated list. We are getting there. May have one more here in Louisiana. I expect a few more as there are some participating in the TRF Traveler that seem to be under the impression that they are one and the same. We'll see.
  1. shawn_rocket ---- Missouri
  2. jbrracer ---- Indiana
  3. Wally Ferrer ---- Virginia
  4. Tobor ---- Illinois
  5. bobbyg23 ---- South Dakota
  6. dhbarr ---- Oklahoma
  7. jqavins ---- New York
  8. CPUTommy ---- Massachusetts
  9. rdbrown ---- Kansas
  10. Tractionengines --- Ohio
  11. Sooner Boomer -- Oklahoma
  12. tsmith1315 --- Georgia
  13. TheTank ------ Connecticut
  14. tcblightning ---- Arkansas

It was brought to my attention that not everyone has Openrocket or Rocsim and I can't wrap my head around that idea. LOL. I had Openrocket before I had rockets to fly. So I am posting the sim results and a brief write up on said results. Now to those of you who know OR inside and out...I may have missed a detail. I have about 14 iterations of this thing in my sim folder so be gentle. Mass and Cg will change after it is assembled. I will mark the CP, and maybe empty CG, when complete and come back here with the updated file(s). Omitting the retainer doesn't help enough for me to fool with the hook. I will save some mass when I mod the MMT (yes I fixed that you witch hunters 😁) and fin tabs; and there are a few tricks I can use to shave a little here and there. A wood or paper CR up front will help some, the fin tabs will hold the MMT once everything is assembled. I think I can remove enough glass to account for the added mass of the epoxy.

View attachment 445797

View attachment 445813

The wedges on the front of the fins are there to fill the empty fin slots and give it a little bit better profile than just plain ole fins. Removing them helps a little with the mass and stability but not much. The fin tabs will be cut as needed so the file doesn't reflect them perfectly. This will put it at .98 CAL on the mighty D12, over 1 on the C11. Even the F39 has .69 CAL. If that doesn't sit right with you but you insist, smash a half ounce of clay into the tip of the nose cone. But this rocket at that altitude, may want a tracker and a few more eyes. These sims are run on a 3/16" rod, at 34" long. Kick that up to a 42" rod and they all get well over 40 ft/s. I don't know when it is necessary to jump up to a 1/4" rod or a rail but I would suggest the F's be flown on one or the other.

I am sending it the printed adapter. I loaded PLA+ and it prints wonderfully. I don't care if I ever see PETG again. I can play with the design and lighten it a bit but feel free to build your own adapter if you want a lighter version. Or even take a drill to one of the white ones I am sending. The white ones are plain PLA, black ones are PLA+.

I will put a simple 3/16 lug on one side, conformal 1010 guides on another. Printing interchangeable 3/16" and 1/4" lugs seems like an unnecessary complication. If the group thinks it necessary I will gladly do so though. I may again get the feeling to under-simplify things and look harder at it.

I invite the makers to design/print a coupler A/V bay for it so it can be flown DD if anyone so desires. I am willing and able but it wont be done quickly. If anyone wants to do it I can send the piece I cut off so they can get the dimensions correct. I can also send along an Eggtimer Quark.

@rdrown
I did my best with the RKT version. This is how it saves. I can go in and add motors and sims, adjust the dimensions and when I save it loses all that. You will need to reconfigure all the pieces. Sorry about that, but it is what it is. The drag, mass and Cp stay the same. The Cg changes for the better and the RKT version has better results all the way around.

@DeepOvertone @neil_w @KC3KNM
I know you aren't signed up, but you showed interest.
 

neil_w

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That certainly looks a lot better. Just a few more comments:
1) Be sure to re-check the numbers after it's built and you can measure final mass and CG. Since you haven't included fillets in the sim, there's gonna be some extra weight in the tail that will impact both.
2) I'd remove the C11, D16, and E11J due to very slow rod speed (note the rocket is considerably above recommended max lift-off for the C11.) Although you can obviously wait until you've finished with #1, so you can work off the final numbers.
3) There's a redundant sim in the file for the F39, probably should just delete that unless it's there for a reason.
 

MikeyDSlagle

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That certainly looks a lot better. Just a few more comments:
1) Be sure to re-check the numbers after it's built and you can measure final mass and CG. Since you haven't included fillets in the sim, there's gonna be some extra weight in the tail that will impact both.
2) I'd remove the C11, D16, and E11J due to very slow rod speed (note the rocket is considerably above recommended max lift-off for the C11.) Although you can obviously wait until you've finished with #1, so you can work off the final numbers.
3) There's a redundant sim in the file for the F39, probably should just delete that unless it's there for a reason.
1)
Mass and Cg will change after it is assembled. I will mark the CP, and maybe empty CG, when complete and come back here with the updated file(s).
;) I don't expect to gain much from the epoxy, and I am fairly certain I can make it up elsewhere.
2) That's one of the details I missed. In the explanation I was going to recommend using those on a 4' rod/rail.
3) It is there for an odd reason. And that was to get a clear screen cap of the results, for those that don't have a sim program. Without that blue line that seems to indicate something that it doesn't.
 
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neil_w

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C11s were discontinued for a while but then reinstated under the new ownership. They are available, although not really appropriate for this rocket.
 

MikeyDSlagle

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C11s were discontinued for a while but then reinstated under the new ownership. They are available, although not really appropriate for this rocket.
Gotcha. I've had a stash for some time now I guess. Never knew they went away. Either way. The C18 will work. If I can get the larger field I'll test fly on the C18 and a D15...maybe a D12.
 

KC3KNM

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Updated list. We are getting there. May have one more here in Louisiana. I expect a few more as there are some participating in the TRF Traveler that seem to be under the impression that they are one and the same. We'll see.
  1. shawn_rocket ---- Missouri
  2. jbrracer ---- Indiana
  3. Wally Ferrer ---- Virginia
  4. Tobor ---- Illinois
  5. bobbyg23 ---- South Dakota
  6. dhbarr ---- Oklahoma
  7. jqavins ---- New York
  8. CPUTommy ---- Massachusetts
  9. rdbrown ---- Kansas
  10. Tractionengines --- Ohio
  11. Sooner Boomer -- Oklahoma
  12. tsmith1315 --- Georgia
  13. TheTank ------ Connecticut
  14. tcblightning ---- Arkansas

It was brought to my attention that not everyone has Openrocket or Rocsim and I can't wrap my head around that idea. LOL. I had Openrocket before I had rockets to fly. So I am posting the sim results and a brief write up on said results. Now to those of you who know OR inside and out...I may have missed a detail. I have about 14 iterations of this thing in my sim folder so be gentle. Mass and Cg will change after it is assembled. I will mark the CP, and maybe empty CG, when complete and come back here with the updated file(s). Omitting the retainer doesn't help enough for me to fool with the hook. I will save some mass when I mod the MMT (yes I fixed that you witch hunters 😁) and fin tabs; and there are a few tricks I can use to shave a little here and there. A wood or paper CR up front will help some, the fin tabs will hold the MMT once everything is assembled. I think I can remove enough glass to account for the added mass of the epoxy.

View attachment 445797

View attachment 445813

The wedges on the front of the fins are there to fill the empty fin slots and give it a little bit better profile than just plain ole fins. Removing them helps a little with the mass and stability but not much. The fin tabs will be cut as needed so the file doesn't reflect them perfectly. This will put it at .98 CAL on the mighty D12, over 1 on the C11. Even the F39 has .69 CAL. If that doesn't sit right with you but you insist, smash a half ounce of clay into the tip of the nose cone. But this rocket at that altitude, may want a tracker and a few more eyes. These sims are run on a 3/16" rod, at 34" long. Kick that up to a 42" rod and they all get well over 40 ft/s. I don't know when it is necessary to jump up to a 1/4" rod or a rail but I would suggest the F's be flown on one or the other.

I am sending it the printed adapter. I loaded PLA+ and it prints wonderfully. I don't care if I ever see PETG again. I can play with the design and lighten it a bit but feel free to build your own adapter if you want a lighter version. Or even take a drill to one of the white ones I am sending. The white ones are plain PLA, black ones are PLA+.

I will put a simple 3/16 lug on one side, conformal 1010 guides on another. Printing interchangeable 3/16" and 1/4" lugs seems like an unnecessary complication. If the group thinks it necessary I will gladly do so though. I may again get the feeling to under-simplify things and look harder at it.

I invite the makers to design/print a coupler A/V bay for it so it can be flown DD if anyone so desires. I am willing and able but it wont be done quickly. If anyone wants to do it I can send the piece I cut off so they can get the dimensions correct. I can also send along an Eggtimer Quark.

@rdrown
I did my best with the RKT version. This is how it saves. I can go in and add motors and sims, adjust the dimensions and when I save it loses all that. You will need to reconfigure all the pieces. Sorry about that, but it is what it is. The drag, mass and Cp stay the same. The Cg changes for the better and the RKT version has better results all the way around.

@DeepOvertone @neil_w @KC3KNM
I know you aren't signed up, but you showed interest.
I’m in if it heads my way in spring, weather up here isn’t conducive to much of anything for a while and I don’t want to be an issue. :)

Also, if you guys need any bits or pieces machined, I’d love to help out. Doesn’t seem like there’s anything, but I’ve got weekends free in the shop again for a little while.
 

jbrracer

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I’m in if it heads my way in spring, weather up here isn’t conducive to much of anything for a while and I don’t want to be an issue. :)

Also, if you guys need any bits or pieces machined, I’d love to help out. Doesn’t seem like there’s anything, but I’ve got weekends free in the shop again for a little while.
i need a thrust plate for a 5.5inch with a 75mm mmt 🤪😜
 

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I hope you'll put as large a lug (or set of lugs) as you can on this rocket. I have seen rockets with tight lugs leave, carrying the launch rod. I've also seen them give a light launch stand a good jerk. I've started putting a pair of short 1/4" lugs on every build now, rather than a single, long lug at the CP or CG.
 

jqavins

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I had one with a just slightly tight lug on a heavy, sturdy pad go dragging slowly up the rod and just barely clear it before burnout.
I don't know when it is necessary to jump up to a 1/4" rod or a rail but I would suggest the F's be flown on one or the other.
Someone correct me if I'm wrong, but I do believe that the need for heavier rods or to go to rails has to do only with the weight of the rocket, not the enfine choice. If the weight means a 3/16" rod is OK for a D12 then it's OK for F engines. At this weight, the concensus seems to be that1/4 inch is a better idea; if so then it's as needed on a C18 as on anything else.
 

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View attachment 445797

View attachment 445813

I assume that these attachments are sim files. I get an error when I try to go to the attachments. Don’t know if it is because I use a Mac or what. The page it goes to says “ oops. Seems to be a problem loading this page.”
 

MikeyDSlagle

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View attachment 445797

View attachment 445813

I assume that these attachments are sim files. I get an error when I try to go to the attachments. Don’t know if it is because I use a Mac or what. The page it goes to says “ oops. Seems to be a problem loading this page.”
Not sure the problem. Send me your email through conversation and I'll email them to you.
 

MikeyDSlagle

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I had one with a just slightly tight lug on a heavy, sturdy pad go dragging slowly up the rod and just barely clear it before burnout.
Someone correct me if I'm wrong, but I do believe that the need for heavier rods or to go to rails has to do only with the weight of the rocket, not the enfine choice. If the weight means a 3/16" rod is OK for a D12 then it's OK for F engines. At this weight, the concensus seems to be that1/4 inch is a better idea; if so then it's as needed on a C18 as on anything else.
You are likely right. I didn't know if high thrust motors may cause excess rod whip. I don't scratch build and fly small rockets enough to know. I do build Estes kits but use the guides included with them. Unless of course it is big enough to accept buttons.
 

DeepOvertone

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I think 1/4” lugs are a good idea. You can still fly it on a smaller rail with the bigger lugs. That being said, I’ll probably still use the buttons.
 

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