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Old 09-19-2009, 09:37 PM   #4 (permalink)
itsmedc
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Join Date: Aug 2009
Location: Near Atlanta, GA
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Question on boattail length

Thanks for the update and inspiration; have been reading all the info old and new on the T-100 and a lot of other materials. Look forward to the next update.

Have a question for you.
I have a 72 Dodge D100 Shortbed which is the first year of the redesign after the style from the late 60's and was used in its basic form up into the 80's. This is a 3rd vehicle used for some hauling and occasional pulling of a pop up camper. I check every tankful of gas but it does not get driven a lot. Also have picked up several sheets of aluminum sign material, for FREE, since they were throwing the old signs away. After a lot of reading, thinking, and studying that includes "SAE 881874 Pickup Truck Drag Reduction...Without Limiting Truck Utility" my plan is to combine a
- 24 inch long cab width wing at 8 degrees down angle
- with a partial bed cover.
The truck came with a 24 inch long over the rail toolbox behind the cab that I use; also has tubular bed rail protectors attached to the box.
The bed cover plan includes a removeable 12 inch extension past the tailgate in the up position, with sides and bottom similar to the bed extension you did but, with an open back. This is after looking at the ATDynamics Trailer Tail for Class 8 truck trailers. Will also be working on a tray to go under the rear bumper and forward to the back edge of the rear wheel well.

My question, finally, is about the length of the tail extension;
? based on your experience, is a 12 inch open back extension, with the proper angles likley to provide a measurable benefit or would it need be longer?

Note I am also planning several other mods before the tail extension including the previously mentioned wing and bed cover as well as:
- partial grill blocks, angled from the bumper to the hood, that includes improved control of the air flowing to radiator
- and a front tray / splitter from bottom of bumper back to the low hanging frame / suspension points with deflectors for the front tires
- and partial belly pans from the edges of the cab and bed over to the frame running from front wheel wells all the way back to the rear wheel wells.
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Last edited by itsmedc; 09-19-2009 at 10:22 PM.. Reason: clarity of info and add picture
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