Twenty-plus years ago, when I was just getting into mid-power, I picked up an Aerotech HV Arcas kit on the way home from a launch. It was my third mid-power rocket, and it very quickly became one of my Fly-it-every-time-go-to rockets. I still have it, as well as the other two mid-power birds from that time (T.H.O.Y. Wasp and a Vaughn Brothers Javelin; all still flyers).
Not long after building the HV Arcas kit, I came across a drawing in one of Peter Alway's books (The Art of Scale Model Rocketry, as I recall) of the boosted Sparrow/HV Arcas sounding rocket. The light bulb above my head quickly began to flicker and I started drawing up a staged version of the Sparrow/Acras using a clone of the Aerotech kit as the sustainer.
I ordered up some heavier tubes, plywood CRs and bulkheads, and the Aerotech plastic fins and nosecone and had the basic rocket built pretty quickly. Certain changes were made to allow for booster attachment, and no launch lugs were installed as they were intended to be mounted on the Sparrow booster (rails and buttons were a couple of years away).
Well, 9/11 shut us all down for a while, other aspects of life intervened as they often do, and the poor Arcas clone sat neglected in the model room.
Until today...
I'm really making an effort to clear up the rather sizable backlog of unfinished projects in the shop (Honest... Really, I am...), and figured it was high time that poor Arcas was finished, painted and flown.
I decided to modernize things a bit by setting it up for dual-deploy using the coupler as the av-bay. This was made easier by the fact that I had not glued the coupler into the payload tube all those years ago. It was fairly easy to make a forward bulkhead from a coupler bulkhead and a centering ring that I had in the parts bin. Three holes were drilled through the coupler where the booster and payload tubes meet and 1/4" carbon tubes glued into the holes in the coupler. These get sanded flush with the outer tube and serve as vent holes, arming switch hole and as locating pins for the body and payload tube.
Okay, I'm sure that confused everybody, so please forgive my lack of clarity and check out the pics. I think they will clear it all up!
I also got the rail guides glued on (I like to use the Acme rail guides) and filled and sanded the nosecone. She'll get a few scale details tomorrow, along with a coat of primer.
I haven't given up on flying it as the sustainer on the Sparrow booster, in fact, it will be easier to do now with all of the electronics available. (Seems to me there was a discussion concerning mercury switches and flashbulbs back then...).
It will also be easier to get the details correct thanks to @Ez2cDave who very graciously provided me with a wealth of scale data on the Arcas, HV Arcas, Boosted Arcases and Sparrow missiles. Thanks again Dave, I continue to be amazed at your collection of data and your generosity!
Enough rambling, here are some pics:
Here she is with her older brother...
Coupler with carbon tubes for vent holes...
Inside the coupler. The long tube will locate the sled so that the switch is in the proper position relative to the hole (Still need to clean up the inside a bit).
Here's how it goes together. The payload (main chute) tube will be attached to the coupler/av-bay with screws.
Rail guides (and messy bench)...
As always, thanks for lookin'!
Mike
Not long after building the HV Arcas kit, I came across a drawing in one of Peter Alway's books (The Art of Scale Model Rocketry, as I recall) of the boosted Sparrow/HV Arcas sounding rocket. The light bulb above my head quickly began to flicker and I started drawing up a staged version of the Sparrow/Acras using a clone of the Aerotech kit as the sustainer.
I ordered up some heavier tubes, plywood CRs and bulkheads, and the Aerotech plastic fins and nosecone and had the basic rocket built pretty quickly. Certain changes were made to allow for booster attachment, and no launch lugs were installed as they were intended to be mounted on the Sparrow booster (rails and buttons were a couple of years away).
Well, 9/11 shut us all down for a while, other aspects of life intervened as they often do, and the poor Arcas clone sat neglected in the model room.
Until today...
I'm really making an effort to clear up the rather sizable backlog of unfinished projects in the shop (Honest... Really, I am...), and figured it was high time that poor Arcas was finished, painted and flown.
I decided to modernize things a bit by setting it up for dual-deploy using the coupler as the av-bay. This was made easier by the fact that I had not glued the coupler into the payload tube all those years ago. It was fairly easy to make a forward bulkhead from a coupler bulkhead and a centering ring that I had in the parts bin. Three holes were drilled through the coupler where the booster and payload tubes meet and 1/4" carbon tubes glued into the holes in the coupler. These get sanded flush with the outer tube and serve as vent holes, arming switch hole and as locating pins for the body and payload tube.
Okay, I'm sure that confused everybody, so please forgive my lack of clarity and check out the pics. I think they will clear it all up!
I also got the rail guides glued on (I like to use the Acme rail guides) and filled and sanded the nosecone. She'll get a few scale details tomorrow, along with a coat of primer.
I haven't given up on flying it as the sustainer on the Sparrow booster, in fact, it will be easier to do now with all of the electronics available. (Seems to me there was a discussion concerning mercury switches and flashbulbs back then...).
It will also be easier to get the details correct thanks to @Ez2cDave who very graciously provided me with a wealth of scale data on the Arcas, HV Arcas, Boosted Arcases and Sparrow missiles. Thanks again Dave, I continue to be amazed at your collection of data and your generosity!
Enough rambling, here are some pics:
Here she is with her older brother...
Coupler with carbon tubes for vent holes...
Inside the coupler. The long tube will locate the sled so that the switch is in the proper position relative to the hole (Still need to clean up the inside a bit).
Here's how it goes together. The payload (main chute) tube will be attached to the coupler/av-bay with screws.
Rail guides (and messy bench)...
As always, thanks for lookin'!
Mike
mad
