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<p><span style="font-family: 'Courier New',monospace;">[CCing the nrvr-members mail list so this will be archived]</span></p>
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<p><span style="font-family: 'Courier New',monospace;">Wow.. if large autonomous roverer/rocket design is going to be at the meeting, that would rock! (but also really suck bc I'm going to miss the meeting. I'm a huge arduino geek and would LOVE to see an autonomous
arduino-rover pop out of a big bird! <img class="EmojiInsert" alt="😊" style="vertical-align: bottom; font-family: 'Courier New',monospace;" src="cid:33e5bfa0-629c-46b4-8194-849471f9430c"> ) Here's one of my little arduino bots I was thinking about popping
out of my next big rocket (currently seeking a nice big fat rocket for this):</span></p>
<p><span style="font-family: 'Courier New',monospace;"><img tabindex="0" contextid="img570891" sizeoption="best" id="img709303" style="max-width: 99.9%; -moz-user-select: none;" contenttype="image/jpeg" size="0" src="cid:b4102d3e-05f8-4cd3-95a0-84bc6ea33326"><br style="">
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<p><span style="font-family: 'Courier New',monospace;">I'm eager to hear what Bob has to say about 1inch standoffs, but I<font style="font-size: 11pt;" color="#000000">'ve done some 3/4" standoffs for rail buttons on one of my fat-nose rocket designs. It can
be done very robustly if you do it right. </font></span></p>
<br style="font-family: 'Courier New',monospace;">
<p><span style="font-family: 'Courier New',monospace;">But you're rocket is going to be pretty heavy it sounds.. so before showing how it should be done there's a common way you should probably AVOID doing it. Below is the common way to make rail-botton standoffs
for smaller/lighter large nose rockets (which you probably want to avoid):<br style="">
</span></p>
<img style="-moz-user-select: none; font-family: 'Courier New',monospace;" src="https://www.apogeerockets.com/images/apogee_products/Rail_Button_with-standoff.gif"><br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;"></span><br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;">It looks nice, but taking that design out to 1" would give you too much button torque on a large heavy bird. Plus the screw/epoxy nipple inside your BT (body tube) will create a snag point for any recovery
gear/chutes. But the torque from the 1inch of clearance is the real problem with a rocket as heavy as yours.</span><br style="font-family: 'Courier New',monospace;">
<br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;">Instead, here's a graphical view of how I did it (on this smaller 2.6" rocket design) using streamlined basswood blocks and T-nuts creating a much wider "hugging footprint" to the standoff (VERY solid):</span>
<p><span style="font-family: 'Courier New',monospace;"><img tabindex="0" contextid="img514481" sizeoption="best" id="img183861" style="max-width: 99.9%; -moz-user-select: none;" contenttype="image/png" size="0" src="cid:6c8e1aa4-7eb2-49c6-b1d8-71e004b4c7de"></span></p>
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<p><a title="Ctrl+Click or tap to follow the link" id="LPlnk1133" href="http://theweeks.org/rockets/HONEST-JOHN/NOSECONE/dscf0107.jpg"><span style="font-family: 'Courier New',monospace;">http://theweeks.org/rockets/HONEST-JOHN/NOSECONE/dscf0107.jpg</span></a></p>
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<p>The block is sanded to fit the tube by simply putting the sandpaper (rough side up) and sanding the button-block directly against the BT.. creating a perfect fit to hug your BT and give you a solid anchor.<br>
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<p><span style="font-family: 'Courier New',monospace;">This design yields MUCH more lateral rocking resistance (than a simple, columnar plastic standoff). If interested, I have some more pics of this design at home I can put on my webserver tonight.. I did
a longer 3inch block standoff like this that will give you room for both outward and inward facing T-nuts. Tricky getting it all screwed down without any snag-points, but VERY solid, and you end up with nuts and bolts anchoring the button base to the BT, (not
just some epoxy or a 1inch plastic cylinder). </span></p>
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</span></p>
<p><span style="font-family: 'Courier New',monospace;">For an even more solid anchor, you could also go with a larger triangular block base with three outward facing threads (t-nut style) with flush-nut-head inside and screw bolts from the outside with an internal
re-inforcing ring (fiberglass or aluminum ring) that the internal flush-nut mount the block to to give it a super solid mount point. Email me off list and I'll get you the other design photos.<br style="">
</span></p>
<span style="font-family: 'Courier New',monospace;"></span><br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;">Also.. </span><br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;">If this is your first HP rocket.. I would recommend comparing deisng notes by the experienced experts in the nrvr.org mail list (CCd). If you're not a member, students can join for free here
</span><a id="LPlnk543630" href="http://nrvr.org/membership/"><span style="font-family: 'Courier New',monospace;">http://nrvr.org/membership/</span></a><span style="font-family: 'Courier New',monospace;">.</span><br style="font-family: 'Courier New',monospace;">
<br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;">However, to beef up on HP rocket design best practices I recommend picking up a copy of this excellent HP rocket design book that has decades of big-rocket design wisdom:</span><br style="font-family: 'Courier New',monospace;">
<a id="LPlnk533201" href="http://www.amazon.com//dp/1412058104"><span style="font-family: 'Courier New',monospace;">http://www.amazon.com//dp/1412058104</span></a><br style="font-family: 'Courier New',monospace;">
<br style="font-family: 'Courier New',monospace;">
<br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;">Any of you other guys have </span>
feedback?<br>
<br>
Bob? You done any heavy rocket button standoffs?<br>
<br>
Tweeks<br>
p.s. Fareez.. with a rocket this big/heavy.. you ARE using the larger 1515 buttons right?
<a id="LPlnk149133" href="http://aeroconsystems.com/cart/launch-and-recovery-accessories/rail-button-8020-style-1515-pair/">
http://aeroconsystems.com/cart/launch-and-recovery-accessories/rail-button-8020-style-1515-pair/</a> (unless Bob recommends something beefier)<br style="font-family: 'Courier New',monospace;">
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size: 11pt; font-family: 'Courier New',monospace;" color="#000000"><b style="">From:</b> Fareez Chowdhury <fareez.chowdhury@gmail.com><br>
<b style="">Sent:</b> Monday, December 7, 2015 1:17 PM<br>
<b style="">To:</b> Bob Schoner<br>
<b style="">Cc:</b> Kevin Shinpaugh; james desposito; Jim Farley; Jordan Truesdell; Carlos Zapata; officers@nrvr.org Officers; Pat Artis; Brad Smith; Eric Plevy; Magda Moses; Johnny Jaffee; Ishan Arora<br>
<b style="">Subject:</b> Re: Meeting with NRVR</font><span style="font-family: 'Courier New',monospace;">
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<div dir="ltr"><span style="font-family: 'Courier New',monospace;">Mr. Schoner, </span>
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<div><span style="font-family: 'Courier New',monospace;">Any and all advice would be appreciated. I've CC'd the remainder of the team so they can be in on this. In case anyone is curious, I am also attaching the PDR we've submitted to the competition organizers
and for which we'll present on Wednesday morning, as well as the OpenRocket file we've got going on right now. </span></div>
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</span></div>
<div><span style="font-family: 'Courier New',monospace;">An additional question would probably be: how would you recommend going about building a 1" standoff for railbuttons? If you'll see from our rocket file (and alluded to in one of the other questions),
our rocket has two diameters, and the lower stage is of smaller diameter than the upper. Since it is not possible to mount the rail buttons on the upper section due to payload reasons, we need to build standoffs for our railbuttons so the buttons (attached
to the smaller diameter tube) can reach past the larger diameter upper stage and connect to the rails. What kind of shape/material/size would those stand-offs be, etc.?</span></div>
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<div class="gmail_quote"><span style="font-family: 'Courier New',monospace;">On Mon, Dec 7, 2015 at 9:16 AM, Bob Schoner
</span><span style="font-family: 'Courier New',monospace;" dir="ltr"><<a href="mailto:bob.schoner@gmail.com" target="_blank">bob.schoner@gmail.com</a>></span><span style="font-family: 'Courier New',monospace;"> wrote:</span><br style="font-family: 'Courier New',monospace;">
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<div><span style="font-family: 'Courier New',monospace;">Kevin,</span></div>
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<div><span style="font-family: 'Courier New',monospace;">Lets's put this on our calendar and move forward with it. I will update the calendar on our webpage.</span></div>
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<span style="font-family: 'Courier New',monospace;">Officers, </span>
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<div><span style="font-family: 'Courier New',monospace;">We still have interested VT students that we can help out. These are some great questions and are always preferred over assumptions when folks are getting into high power rocketry. I don't mind addressing
one or two of these, but would like more people to help out and add their perspective too.</span></div>
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<div><span style="font-family: 'Courier New',monospace;">I feel like I can offer something on any of these and will volunteer to speak on #2.<br style="">
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<div><b style="font-family: 'Courier New',monospace;">Officers and NRVR members, please reply all to:</b></div>
<div><b style="font-family: 'Courier New',monospace;"> - indicate if you can make this meeting for 12/9 at 6:00 p.m.</b></div>
<div><b style="font-family: 'Courier New',monospace;"> - indicate which topic you want to address or research</b></div>
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<div><span style="font-family: 'Courier New',monospace;">We can certainly invite all our members as this may be of interest to them. I know December is busy and we are not giving them too much notice. Any objections to open this up to the whole NRVR community?
</span></div>
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<div><span style="font-family: 'Courier New',monospace;">I'm inviting the L1 and L22 people that I can remember. Think back to some of the assumptions you made when you first started and see if you have some advice on any of these topics.</span></div>
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<div><span style="font-family: 'Courier New',monospace;">Since Time is short, please reply no later than 11:00 pm of 12/7.</span></div>
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<div><span style="font-family: 'Courier New',monospace;">Thanks</span></div>
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<div>Bob </div>
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<div class="gmail_quote"><span style="font-family: 'Courier New',monospace;">On Sun, Dec 6, 2015 at 4:03 PM, Kevin Shinpaugh
</span><span style="font-family: 'Courier New',monospace;" dir="ltr"><<a href="mailto:kashin@vbi.vt.edu" target="_blank">kashin@vbi.vt.edu</a>></span><span style="font-family: 'Courier New',monospace;"> wrote:</span><br style="font-family: 'Courier New',monospace;">
<span style="font-family: 'Courier New',monospace;"></span>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex">
<div style="word-wrap:break-word"><span style="font-family: 'Courier New',monospace;">I think we can get an NRVR meeting with you all for after 6pm on Thursday.
</span>
<div><span style="font-family: 'Courier New',monospace;">Space@VT will be a good meeting location.</span></div>
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<div><span style="font-family: 'Courier New',monospace;">On Dec 6, 2015, at 3:16 PM, Fareez Chowdhury <</span><a href="mailto:fareez.chowdhury@gmail.com" target="_blank"><span style="font-family: 'Courier New',monospace;">fareez.chowdhury@gmail.com</span></a><span style="font-family: 'Courier New',monospace;">>
wrote:</span></div>
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<div><span style="font-family: 'Courier New',monospace;">Dr. Shinpaugh, </span></div>
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<div><span style="font-family: 'Courier New',monospace;">At the last meeting, you wanted us to remind you to ask NRVR if we can schedule a meeting at Space@VT on Thursday (12/10) at 5:00 PM, to discuss some rocket concepts and verify some things you guys are
doing. We also have a preliminary list of questions we wanted to ask:</span></div>
<div>
<ol>
<li><span style="font-family: 'Courier New',monospace;">Advice for cutting accurate fin slots</span></li><li><span style="font-family: 'Courier New',monospace;">Filleting fins to body tube at root</span></li><li><span style="font-family: 'Courier New',monospace;">How to prevent parachute tangling at apogee (booster main chute and capsule drogue chute)</span></li><li><span style="font-family: 'Courier New',monospace;">Adding a shoulder to a modified LOC PNC 7.51 in nosecone to convert it into a 7.51 in to 5.51 in transition piece</span></li><li><span style="font-family: 'Courier New',monospace;">Advice on parachute deployment bag selection for capsule main chute</span></li><li><span style="font-family: 'Courier New',monospace;">Amount of black powder and Pyrodex required for recovery</span></li></ol>
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<div><span style="font-family: 'Courier New',monospace;">Please let us know as soon as possible. Thanks!</span></div>
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<div>Fareez Chowdhury</div>
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<div style="font-size:12.8px"><font style="font-family: 'Courier New',monospace;" size="1">Mechanical Engineering<br>
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<font style="" size="1">Virginia Tech, Class of 2017</font><br>
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<div><span style="font-family: 'Courier New',monospace;">Fareez Chowdhury</span></div>
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<div style="font-size:12.8px"><font style="font-family: 'Courier New',monospace;" size="1">Mechanical Engineering<br>
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<span style="font-family: 'Courier New',monospace;"></span><font style="font-family: 'Courier New',monospace;" size="1">Virginia Tech, Class of 2017</font><br style="font-family: 'Courier New',monospace;">
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