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September 21, 2011

First Glider


While experimenting with wing bodies, I notched the tail to allow the hybrid rocket mass to be forward without burning any tail feathers off.  The notch suggested parking another larger vehicle behind the orbiter.  Any in-line joining of fuselage types puts all the structural load on a small footprint.  When we use the flying wing, we have a long overlap, like the rank insignia of a corporal.  This “chevron” overlap allows a long footprint fore and aft for hard points.  This reduces the moment arm on the structural joints.

It doesn’t reduce the need for two aircraft to balance when joined.  Could this be done?  I made some drawings and a big mess in the garage to find out.  The unpainted glider was successful on the first try.  Beginner’s luck is fun!  I also noticed that the combined flight was better than either stage flown by itself.  We may be seeing lift from the first stage wings after the air has alread produced lift flowing over the second stage wings.

I purchased a model kit and began tearing it apart for its radio controls.  Balancing these parts on the glider projected how the redesign should go for a balanced powered model.  The second stage was the most challenging to test because of its low aspect ratio and high wing loading.  My first model was overweight so as a glider it was a real test.  As it happens the glide test was quite successful, encouraging the next revisions to go for both stages.



LEAP P2.2 R/C Glider

It looks like it will work, but does it offer an advantage?  Current hroizontal proposals are either blunt “truck” shapes or sleek pointy designs.  If one would use the atmospheric oxygen, it is found at lower elevations which seem to compel sharp forms for maximum acceleratrion.

Skylon SSTO

The British Skylon high tech propulsion seeks the sleek solution for it’s flight path.  Similarly the British Space Cab sought a “fine” or sharp profile.  Yet Andrews Space oxygen harvesting system is content to use a more conservative shuttle shape.

Andrews Space proposals

Our design targets a subsonic climb with conventional jet engines to 40-50 K feet.  At that point rockets complete the first stage mission.  By using in-line staging, our frontal area is partially masked for reduced drag.  The smaller vehicle breaks the airflow with its smaller frontal area, but the booster still sees some lift from the same flow.  It has the effect of making a blunt vehicle behave a bit like the sleeker ones.  It may be like NASCAR racers drafting to boost the efficiency of both vehicles.

Frontal Area Masked

Small improvements to the airframe may position us to further help the new propulsion systems when they do mature.  It also offers some potential for improved safety in staging.  Vertical launch rockets have been staging in-line for decades, somtimes using pneumatic stage boosters.  We plan a catapault system like this for in-line separation.  Piggy back separation and drop systems are threatened with potential vehicle collisions in turbulant conditions.  Boeing has an elegant patent for a system that swings the orbiter down on swing arms, and offers a streamlined booster to accelerate a more shuttle like orbiter.

Boeing orbital system

This cuts the frontal area down but does not gain lift from the orbiter’s wings.  This requires a larger booster stage with more wing area and more mass.  The LEAP system may offer the most lift per drag and mass possible in horizontal launch.

LEAP side view

This may be a case where smaller is better.  We would like to target the role of the little DC3 in providing a small payload on a regular schedule.  Safety is a factor to do this, and one extra stage is a sacrifice for that goal.  Over time every launch system will experience failures.  We need to let the crew survive these to keep the system on line as long as possible.  Our third stage is based on the patent of the TAAS aircraft escape cabin system.

Crew Rescue Vehicle

This allows the second stage to escape any first stage malfunctions, and the capsule can depart from the second stage if that too is in failure.  I hope this kind of redundancy will be implemented before commercial mishaps threaten a new market.  Admittedly it hammers our mass fraction, but the human mission may need the cushion to keep the industry on line.  Shuttle disasters took a toll on lives and system shutdowns for years.  We can’t afford any more gaps in service to such a critical  mission area.  Spaceflight is now manditory for war and peace.



  1. Chris permalink


    Any news on the LEAP project?


  2. Yes, NASA offered a simple two page format for innovative technologies this month. We will apply shortly.

  3. Awesome you should think of soetnhimg like that

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