While waiting for Tiamat primer 1st 3 coatings to cure, I'll return to work on a model that has been in the beginning stages since 2003.
Lockheed x7A Ram-Jet test bed vehicle with large Booster. This scale model has been in my build que since feburary of 2003.
I completed the 8.5" x 14" McCoys' Micro Wonder Works drawing July 7, 2003.
Deciding on what size this model should end up being more of a problem than invisioned. I wanted to try to stage this model but the offset adaptor transition just made that option hightly unlikely. I decided to simplify the offset transition just a little making the offset slightly straighter and then decided that T3 (.375") Booster body tube would be my starting point, translated to scale that gave me a 1: 81.3 scale with a miltiplier of .0123.
Once the drawings were at least in usable shape the actual "Hard Part" of turning the scale ramjet, transition and nosecone began Aug. 20, 2003. The actual x-7A turned out to be T2 (.246"od) so there is no way it will ever be flown without a booster. I also noted the nose probe would be far to fragile to be made out of wood or plastic so. the drawing as labled for this part to be turned from 1/16" brass rod. with a 3/8" insertable aft end. The hope is it's mass will help limit the amount of nose-weight required to make the combined x-7A & Booster stable. I'm still looking at cardboard cutouts and a rought roc-sim approximation for a Cp-CG relations.
Once these paliminary steps were done I turned the basswood parts and then set the project aside until June 29th of this year. I still really wanted to find a way to stage this bad boy but without completely starting over from scratch using a much larger scale it just wasn't going to happen.
Over the last couple months while working on other projects, I dug a little deeper into the history for this Lockheed project and found a couple color photos that had eluded me during the hunt.. Now I knew what the basic color scheme would be over the old black & white photos that had stirred the interest orginally. My model would be based on the 06-20-1960 Lockheed test flight prototype.
So here we go: Working from pieces of the draft MMWW scale drawing our parts were sized & shaped using file folder patterns to transfer score lines and details to the .020" & .030" white styrene used for both x-7A and Booster Wings, Tails, & Elevators. orignially the ramjet pylon was also cut from .030" styrene but after a bit more research found this was far too thin, The pylon now started as 1/16" basswood sanded to shape and profile.
Again this model was set aside while I concentrated on the Tiamat scale construction.
so another couple months passed before I could get back to actually mounting any of these styrene parts. One thing I have come to understand. When working with styrene to cardboard joints on this scale the adhesive for the job is Medium CA. and you really need a very good dead flat fin alignment jig to get everything aligned.
Even using my Aluminuim fin alignment jig I had to break off and re-install the vertical tail on the x-7A. We have completed the x-7A construction. added extra lenght to the Booster Adaptor transition and have the MMX Motor mount, 30" - 70lb Shockline and 1/4" x 9" yellow teflon streamer complete and installed.
All that remains will be mounting the very large area Booster Wing/fins and Vertical tail.
Our booster vertical tail is no problem at all, the Booster wings however are offset the hight of the Ramjet pylon, a bit over 9/64".
This offset will have to be shimmed off center much like we did with the x-7A horizontal stabilizers. arranging this shim build up is the hold up for this final construction piece.
Below are a few pics of where we are so far.
Lockheed x7A Ram-Jet test bed vehicle with large Booster. This scale model has been in my build que since feburary of 2003.
I completed the 8.5" x 14" McCoys' Micro Wonder Works drawing July 7, 2003.
Deciding on what size this model should end up being more of a problem than invisioned. I wanted to try to stage this model but the offset adaptor transition just made that option hightly unlikely. I decided to simplify the offset transition just a little making the offset slightly straighter and then decided that T3 (.375") Booster body tube would be my starting point, translated to scale that gave me a 1: 81.3 scale with a miltiplier of .0123.
Once the drawings were at least in usable shape the actual "Hard Part" of turning the scale ramjet, transition and nosecone began Aug. 20, 2003. The actual x-7A turned out to be T2 (.246"od) so there is no way it will ever be flown without a booster. I also noted the nose probe would be far to fragile to be made out of wood or plastic so. the drawing as labled for this part to be turned from 1/16" brass rod. with a 3/8" insertable aft end. The hope is it's mass will help limit the amount of nose-weight required to make the combined x-7A & Booster stable. I'm still looking at cardboard cutouts and a rought roc-sim approximation for a Cp-CG relations.
Once these paliminary steps were done I turned the basswood parts and then set the project aside until June 29th of this year. I still really wanted to find a way to stage this bad boy but without completely starting over from scratch using a much larger scale it just wasn't going to happen.
Over the last couple months while working on other projects, I dug a little deeper into the history for this Lockheed project and found a couple color photos that had eluded me during the hunt.. Now I knew what the basic color scheme would be over the old black & white photos that had stirred the interest orginally. My model would be based on the 06-20-1960 Lockheed test flight prototype.
So here we go: Working from pieces of the draft MMWW scale drawing our parts were sized & shaped using file folder patterns to transfer score lines and details to the .020" & .030" white styrene used for both x-7A and Booster Wings, Tails, & Elevators. orignially the ramjet pylon was also cut from .030" styrene but after a bit more research found this was far too thin, The pylon now started as 1/16" basswood sanded to shape and profile.
Again this model was set aside while I concentrated on the Tiamat scale construction.
so another couple months passed before I could get back to actually mounting any of these styrene parts. One thing I have come to understand. When working with styrene to cardboard joints on this scale the adhesive for the job is Medium CA. and you really need a very good dead flat fin alignment jig to get everything aligned.
Even using my Aluminuim fin alignment jig I had to break off and re-install the vertical tail on the x-7A. We have completed the x-7A construction. added extra lenght to the Booster Adaptor transition and have the MMX Motor mount, 30" - 70lb Shockline and 1/4" x 9" yellow teflon streamer complete and installed.
All that remains will be mounting the very large area Booster Wing/fins and Vertical tail.
Our booster vertical tail is no problem at all, the Booster wings however are offset the hight of the Ramjet pylon, a bit over 9/64".
This offset will have to be shimmed off center much like we did with the x-7A horizontal stabilizers. arranging this shim build up is the hold up for this final construction piece.
Below are a few pics of where we are so far.
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Wings on the tail was more or less a snap. all three need epoxy fillets to complete the booster. Below are a couple photos or the progress so far. 
