May the fun begin


Tim Dixon
 

Given I am banned for like life from TRF, I thought I may be able to do a few build posts here. I have finally started to assemble my Cherokee-N. The goal is to fly it at Airfest in September. Parts have been laying around for 5-plus years starting back here: 7.74X Cherokee N (Is there a mechanical engineer in the house?). After considering more than a half dozen construction options, I have settled on the "Lego" approach where piece parts will be transported and final assembly done at the launch site as Bill Good did/does with his AGM-78 Standard Arm.


Jonathan Sivier
 

Cool. I look forward to hearing more about it as you make progress.

Chris, how large is your largest Cherokee upscale?

Jonathan

P.S. The rocket you left at GARLO a couple of years ago is orange and blue as you thought. Actually it is orange around the fins fading to white in the middle and then very light blue for the upper portion of the rocket. I'll try to remember to bring it the next time I'm over that way. JES


On 12/26/2020 8:56 PM, Tim Dixon wrote:
Given I am banned for like life from TRF, I thought I may be able to do a few build posts here. I have finally started to assemble my Cherokee-N. The goal is to fly it at Airfest in September. Parts have been laying around for 5-plus years starting back here: 7.74X Cherokee N (Is there a mechanical engineer in the house?) <https://urldefense.com/v3/__https://www.rocketryforum.com/threads/7-74x-cherokee-n-is-there-a-mechanical-engineer-in-the-house.68686/__;!!DZ3fjg!qNSYmvdXsFZ5HPPipcDJ31hZWIT5Yqxhi3KwKRvUHrFgAxMxk7xFGPKxK_7VF3sg_A$>. After considering more than a half dozen construction options, I have settled on the "Lego" approach where piece parts will be transported and final assembly done at the launch site as Bill Good did/does with his AGM-78 Standard Arm.


Tim Dixon
 

Jonathan,

You mean this one? If so, I'd love to get it back!

-Tim


Christopher Deem
 

My largest is 4 inches in diameter.



Sent from my Galaxy


-------- Original message --------
From: Jonathan Sivier <jsivier@...>
Date: 12/26/20 9:07 PM (GMT-06:00)
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] May the fun begin

Cool. I look forward to hearing more about it as you make progress.

Chris, how large is your largest Cherokee upscale?

Jonathan

P.S. The rocket you left at GARLO a couple of years ago is orange and blue as you thought. Actually it is orange around the fins fading to white in the middle and then very light blue for the upper portion of the rocket. I'll try to remember to bring it the next time I'm over that way. JES

On 12/26/2020 8:56 PM, Tim Dixon wrote:
Given I am banned for like life from TRF, I thought I may be able to do a few build posts here. I have finally started to assemble my Cherokee-N. The goal is to fly it at Airfest in September. Parts have been laying around for 5-plus years starting back here: 7.74X Cherokee N (Is there a mechanical engineer in the house?) <https://urldefense.com/v3/__https://www.rocketryforum.com/threads/7-74x-cherokee-n-is-there-a-mechanical-engineer-in-the-house.68686/__;!!DZ3fjg!qNSYmvdXsFZ5HPPipcDJ31hZWIT5Yqxhi3KwKRvUHrFgAxMxk7xFGPKxK_7VF3sg_A$>. After considering more than a half dozen construction options, I have settled on the "Lego" approach where piece parts will be transported and final assembly done at the launch site as Bill Good did/does with his AGM-78 Standard Arm.


M
 

Watching!

 

Mike Z

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Tim Dixon
Sent: Saturday, December 26, 2020 8:56 PM
To: cia-rocketry@groups.io
Subject: [cia-rocketry] May the fun begin

 

Given I am banned for like life from TRF, I thought I may be able to do a few build posts here. I have finally started to assemble my Cherokee-N. The goal is to fly it at Airfest in September. Parts have been laying around for 5-plus years starting back here: 7.74X Cherokee N (Is there a mechanical engineer in the house?) After considering more than a half dozen construction options, I have settled on the "Lego" approach where piece parts will be transported and final assembly done at the launch site as Bill Good did/does with his AGM-78 Standard Arm.


Tim Dixon
 

OK, fin can is structurally complete, with only minimal gaps and excepting a few smudges of blood. Don't have enough left in me to take it apart and show the inside. Maybe tomorrow. Have a few details on the fit of the fins outside of the tabs (want them solidly mating the internal rings, but then stepped up to accommodate the airframe. After that, it will be drilling/installing rivets all around to attach the airframe. Once the booster is done, then lots of internal structural work on subsequent couplers and airframes, and given those steps are new build techniques, I'm not sure how fast or slow that will go.


Christopher Deem
 

Looking good.



Sent from my Galaxy


-------- Original message --------
From: Tim Dixon <dixontj936@...>
Date: 12/29/20 4:54 PM (GMT-06:00)
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] May the fun begin

OK, fin can is structurally complete, with only minimal gaps and excepting a few smudges of blood. Don't have enough left in me to take it apart and show the inside. Maybe tomorrow. Have a few details on the fit of the fins outside of the tabs (want them solidly mating the internal rings, but then stepped up to accommodate the airframe. After that, it will be drilling/installing rivets all around to attach the airframe. Once the booster is done, then lots of internal structural work on subsequent couplers and airframes, and given those steps are new build techniques, I'm not sure how fast or slow that will go.


M
 

Not building out of a Hotel room? I am having a hard time following!..

 

I LIKE IT!

 

Mike Z

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Tim Dixon
Sent: Tuesday, December 29, 2020 4:54 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] May the fun begin

 

OK, fin can is structurally complete, with only minimal gaps and excepting a few smudges of blood. Don't have enough left in me to take it apart and show the inside. Maybe tomorrow. Have a few details on the fit of the fins outside of the tabs (want them solidly mating the internal rings, but then stepped up to accommodate the airframe. After that, it will be drilling/installing rivets all around to attach the airframe. Once the booster is done, then lots of internal structural work on subsequent couplers and airframes, and given those steps are new build techniques, I'm not sure how fast or slow that will go.


Tim Dixon
 

Yeah Mike, hotels are kinda out of the question right now per my doctor.

Had to take a bit of a redirect on the build as I slipped and fell during the ice storm doing a number on my back/ribs. So instead of trying to manhandle the bulky fin can while dealing with spasms, I decided to move to a smaller item/task, the av-bay mechanics. This delay was OK though as after doing a fit of the booster airframe, I decided to go a different direction on the attachment points; upgrading to #10 pan head screws for more surface area, so awaiting a parts delivery on that change anyway.

So, the av-bay is nothing special. In fact, my general direction for this project has been to keep it as simple as possible. I did consider the use of Rouse-tech CO2 ejection, but given the low altitude, it was hard to justify, especially given max black powder is "only" 6 grams due to the large surface area of the bulkheads. I say "only" because, although I have never used that much BP in my life, I have seen some of the QCRS guys using 6 gram charges in airframes of half the diameter, albeit a fiberglass airframe that could survive such a shock.

So the following pictures should be pretty familiar and explanatory. Actually, the real trick in this step was dealing with the inherent slop in the Sonotube dimensions. Since this is one of the two critical slip joints, I had to finesse a couple of more layers of fiberglass laminate to get a more accurate fit. After that, minor adjustments were also required on the bulkhead pairs which was done with a combination of a router pass and some light sanding. Hardware is all 3/8-16 which is sized for the weight and gee forces expected. Outside of that, believe me, I am a recovering over-builder, so am trying to use the minimum of epoxy and reinforcement throughout this and every build I've done for the past 10 years. Saying that I do have reinforcement at critical stress areas, e.g., the bulkhead hardware attachment point where I'm using a swatch of 10oz Kevlar. The fairly large charge holders may or may not be familiar--you can get this large size and a number of smaller sizes at dirt cheap prices by searching for "pill canisters" on eBay. Finally, on the aft bulkplate you see an aluminum plate for the antenna attachment. I now have that drilled for with #2 hardware in the four corners, and the wimpy antenna shown will probably be upgraded to something more stout given the space I have in the airframe. Finally, the last picture is after adding labels and a thin layer of epoxy for ding durability and ease of cleanup.