woferry
Well-Known Member
Hi,
Still fairly new to posting on this forum (and HPR, I flew a few small model rockets growing up, but a co-worker took me to XPRS in 2012 and got me hooked), I've built two HPR rocket kits so far, both GLR (Thunderbolt and Bumbl-B mk III), but this will be my first build thread.
As much as I love the pre-made fin-can idea, I figured its time to try to build up the skill-set (and the number of tools/fixtures in my garage) on doing fins myself. The fact that the Binder Design Excel basically involves building your own fin-can seemed like a good first-step. Plus I was looking for a larger rocket than the minimum diameter ones I've built so far to be able to fly more electronics, have more room to work with recovery bits, etc. I'm definitely not ready to start playing with FG yet, so I chose the Excel w/DD still using plastic and whatever paper-ish material the BT is made from. My goal here is to hopefully get a solid DD flyer, and likely use this for my L2 so that I can fly it higher with some of the larger 54mm motors (realizing that you can't fit the longest cases in this rocket).
For my previous two rockets I had a name and color scheme in mind at the time of (if not even before) ordering the kit. In this case I have a definite color scheme in mind (dark red + black, using Dupli-Color Effex clear over it for a color-changing effect, as I fell in love with the look of dlb's Wildman Jr), but I'm at a complete loss for a name. I think the color effect with red & black would look like some snakes, so I was hoping for a cool snake name (I guess it helps that I had just watched Kill Bill during the holiday), but it seems these colored snakes have totally unimaginative names like "red-bellied black snake". If anyone has any suggestions I'm certainly listening. The OR model really only roughly indicates what will be red & black, the nose cone, avionics bay band and fins I plan to make red and the rest black, except the bottom tube around the fins which will probably be a mix (I liked the pattern on Stewart's Excel DD so I'm planning to mimic that).
I did make two deviations from the stock kit at ordering time, as suggested by others on this forum I asked for the longer motor mount tube (came in at 17") and extra centering ring for it. It seems good to have the longer mount in general, and moving the shock cord anchor higher-up in the tube so that it might still be somewhat accessible seems wise. I also stated at ordering that I didn't need the motor retention as I plan to use an Aero Pack retainer, figuring that might help offset any extra expense Binder might incur for the extra CR & MMT.
Opening the box revealed basically all of the parts I was expecting (and it sure looks nice!). The kit included 1010 rail buttons, for some reason I was expecting a launch lug so I had already ordered buttons separately (I love the Acme conformal rail guides, but have already caught enough flack at launches about the aluminum guides so I figured I'd use the Delrin buttons on non-MD rockets). The included buttons have very short screws and lack a T-nut for the interior, so I'll probably still use the guides I ordered separately which include the T-nut. Two tubular nylon shock cords are included, I'm thinking of switching those out with kevlar since that's what I'm used to from the GLR kits. The main chute is 40" and looks very sturdy, I was rather surprised by the 12" drogue which feels inadequate to me for a rocket of this size & weight, and according to my OR model even with the 'dry-weight' rocket (before adding electronics, epoxy/paint, etc) will come down at 80ft/s (>50mph), which OR warns is fast for deploying the main. A 18" chute looks much better in OR (right around the 50ft/s that generally seems to be recommended speed from what I can tell) so I will probably replace this chute. No chute protection is included either and I'm not too keen on stuffing the tubes with 'dog barf', so I'll likely pick up some nomex/kevlar chute protectors as well. There are also no quick-links for the recovery (just eyebolts for the avionics bay and lower section, with a plastic loop on the nose cone side), which I'd rather have especially if I stick with (or start out with) the nylon cord. The avionics bay kit includes a screw switch, I've used the Featherweight magnetic switch before and liked that, so I have another pair on order for this rocket (for redundant electronics).
So here's the kit as received. I actually ordered two Excels, one DD and one not, the non-DD one is for my dad to build later this spring (I took him to XPRS in 2013, he built/flew a GLR T-Bolt in 2014, and was looking to build a bigger rocket for this year). So the rightmost 3 pieces and bag of bits are for that kit, the rest is for my Excel DD (the pair of extra centering rings is near the middle).
I did a dry-fit of all of the parts (including throwing everything else inside the tube) and weighed it. Came in at 66.3oz. I weighed each major component separately and built as accurate of an initial model in OR as I could (I don't have the Aero Pack retainer yet, so that's missing). I intend to be re-weighing things regularly as I replace/upgrade bits, sand, epoxy, paint, etc. I don't plan on going out of my way for a light build, but would like to get a better understanding of how much weight gets added in the process. I did notice (and I believe I had read it elsewhere, probably on this forum) that the nose cone OD is a bit less than the body tube, so there's a noticeable discontinuity where the two come together. Not sure that I'm going to do anything about that however.
Other than the longer MMT and upgrading some recovery bits as mentioned above, I don't plan on going too custom with this build, most of it will be as recommended in the instructions (I also have a LOC Minie-Magg on order that I plan to go more crazy with, that will get its own thread). I do want to fit my Eggfinder in the nose cone, I don't want to remove the center portion of this nose cone's base, so I'm hoping to be able to drill a hole for either BT-55 or 29mm tubing off-center on the NC bottom face (which angles in anyway), and fitting a piece of wood in so that it doesn't require all-thread (with pins/screws in the back to hold things in place). This would also help for adding some nose weight if I ever decide to fly this in the shorter (non-DD) configuration. I also have a Mobius ActionCam that I plan to fly on this rocket, so I have a camera shroud on order from Landru13 (I've flown one of these on Bumbl-B and really like it, link to my first videos in the signature).
Unfortunately, since I don't have the retainer yet I won't be starting with the fin can, as I need the retainer to ensure I position the thrust plate properly on the MMT. I do have some prep-work to do anyhow, I want to build one of the fin alignment jigs as from this thread. I also picked up a drill press from Lowes that I need to put together, and I want to build my own paint booth as well. But I'll likely start the build with the avionics bay. The grooves aren't as pronounced on this tube as the GLR Magna-frame, but I'll probably start out filling them to kill time. I want to try this trick of 'soaking' the ends of the tubes in CA, though I'm not quite sure the proper CA to use for this, is it something I can buy at a hardware store or do I need more of a hobby/craft shop or something? Everything I see in HD/Lowes that is thin claims to be instant-set which scares me.
I'm hoping to have this ready for the local February launches (LUNAR and/or TCC), we'll have to see how much time I get to work on it this month.
Still fairly new to posting on this forum (and HPR, I flew a few small model rockets growing up, but a co-worker took me to XPRS in 2012 and got me hooked), I've built two HPR rocket kits so far, both GLR (Thunderbolt and Bumbl-B mk III), but this will be my first build thread.
As much as I love the pre-made fin-can idea, I figured its time to try to build up the skill-set (and the number of tools/fixtures in my garage) on doing fins myself. The fact that the Binder Design Excel basically involves building your own fin-can seemed like a good first-step. Plus I was looking for a larger rocket than the minimum diameter ones I've built so far to be able to fly more electronics, have more room to work with recovery bits, etc. I'm definitely not ready to start playing with FG yet, so I chose the Excel w/DD still using plastic and whatever paper-ish material the BT is made from. My goal here is to hopefully get a solid DD flyer, and likely use this for my L2 so that I can fly it higher with some of the larger 54mm motors (realizing that you can't fit the longest cases in this rocket).
For my previous two rockets I had a name and color scheme in mind at the time of (if not even before) ordering the kit. In this case I have a definite color scheme in mind (dark red + black, using Dupli-Color Effex clear over it for a color-changing effect, as I fell in love with the look of dlb's Wildman Jr), but I'm at a complete loss for a name. I think the color effect with red & black would look like some snakes, so I was hoping for a cool snake name (I guess it helps that I had just watched Kill Bill during the holiday), but it seems these colored snakes have totally unimaginative names like "red-bellied black snake". If anyone has any suggestions I'm certainly listening. The OR model really only roughly indicates what will be red & black, the nose cone, avionics bay band and fins I plan to make red and the rest black, except the bottom tube around the fins which will probably be a mix (I liked the pattern on Stewart's Excel DD so I'm planning to mimic that).
I did make two deviations from the stock kit at ordering time, as suggested by others on this forum I asked for the longer motor mount tube (came in at 17") and extra centering ring for it. It seems good to have the longer mount in general, and moving the shock cord anchor higher-up in the tube so that it might still be somewhat accessible seems wise. I also stated at ordering that I didn't need the motor retention as I plan to use an Aero Pack retainer, figuring that might help offset any extra expense Binder might incur for the extra CR & MMT.
Opening the box revealed basically all of the parts I was expecting (and it sure looks nice!). The kit included 1010 rail buttons, for some reason I was expecting a launch lug so I had already ordered buttons separately (I love the Acme conformal rail guides, but have already caught enough flack at launches about the aluminum guides so I figured I'd use the Delrin buttons on non-MD rockets). The included buttons have very short screws and lack a T-nut for the interior, so I'll probably still use the guides I ordered separately which include the T-nut. Two tubular nylon shock cords are included, I'm thinking of switching those out with kevlar since that's what I'm used to from the GLR kits. The main chute is 40" and looks very sturdy, I was rather surprised by the 12" drogue which feels inadequate to me for a rocket of this size & weight, and according to my OR model even with the 'dry-weight' rocket (before adding electronics, epoxy/paint, etc) will come down at 80ft/s (>50mph), which OR warns is fast for deploying the main. A 18" chute looks much better in OR (right around the 50ft/s that generally seems to be recommended speed from what I can tell) so I will probably replace this chute. No chute protection is included either and I'm not too keen on stuffing the tubes with 'dog barf', so I'll likely pick up some nomex/kevlar chute protectors as well. There are also no quick-links for the recovery (just eyebolts for the avionics bay and lower section, with a plastic loop on the nose cone side), which I'd rather have especially if I stick with (or start out with) the nylon cord. The avionics bay kit includes a screw switch, I've used the Featherweight magnetic switch before and liked that, so I have another pair on order for this rocket (for redundant electronics).
So here's the kit as received. I actually ordered two Excels, one DD and one not, the non-DD one is for my dad to build later this spring (I took him to XPRS in 2013, he built/flew a GLR T-Bolt in 2014, and was looking to build a bigger rocket for this year). So the rightmost 3 pieces and bag of bits are for that kit, the rest is for my Excel DD (the pair of extra centering rings is near the middle).
I did a dry-fit of all of the parts (including throwing everything else inside the tube) and weighed it. Came in at 66.3oz. I weighed each major component separately and built as accurate of an initial model in OR as I could (I don't have the Aero Pack retainer yet, so that's missing). I intend to be re-weighing things regularly as I replace/upgrade bits, sand, epoxy, paint, etc. I don't plan on going out of my way for a light build, but would like to get a better understanding of how much weight gets added in the process. I did notice (and I believe I had read it elsewhere, probably on this forum) that the nose cone OD is a bit less than the body tube, so there's a noticeable discontinuity where the two come together. Not sure that I'm going to do anything about that however.
Other than the longer MMT and upgrading some recovery bits as mentioned above, I don't plan on going too custom with this build, most of it will be as recommended in the instructions (I also have a LOC Minie-Magg on order that I plan to go more crazy with, that will get its own thread). I do want to fit my Eggfinder in the nose cone, I don't want to remove the center portion of this nose cone's base, so I'm hoping to be able to drill a hole for either BT-55 or 29mm tubing off-center on the NC bottom face (which angles in anyway), and fitting a piece of wood in so that it doesn't require all-thread (with pins/screws in the back to hold things in place). This would also help for adding some nose weight if I ever decide to fly this in the shorter (non-DD) configuration. I also have a Mobius ActionCam that I plan to fly on this rocket, so I have a camera shroud on order from Landru13 (I've flown one of these on Bumbl-B and really like it, link to my first videos in the signature).
Unfortunately, since I don't have the retainer yet I won't be starting with the fin can, as I need the retainer to ensure I position the thrust plate properly on the MMT. I do have some prep-work to do anyhow, I want to build one of the fin alignment jigs as from this thread. I also picked up a drill press from Lowes that I need to put together, and I want to build my own paint booth as well. But I'll likely start the build with the avionics bay. The grooves aren't as pronounced on this tube as the GLR Magna-frame, but I'll probably start out filling them to kill time. I want to try this trick of 'soaking' the ends of the tubes in CA, though I'm not quite sure the proper CA to use for this, is it something I can buy at a hardware store or do I need more of a hobby/craft shop or something? Everything I see in HD/Lowes that is thin claims to be instant-set which scares me.
I'm hoping to have this ready for the local February launches (LUNAR and/or TCC), we'll have to see how much time I get to work on it this month.
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