Not that it will be any comfort, but IMO you can not fail at a Deltie. You just can't. You mark the body where Rob says to in the instructions. You get it to balance right there. It will glide. You can tweak it with clay after the first launch, but if you build it like he writes, and you balance it at the mark he has you make, it will glide. My last one required nothing. No weight. It just worked.

I have built 3 of them and lost 2 . But both were lost to the Rocket Gods who flew them to their temple in the sky!

My third one I learned to
A) Clone the glider from a newly bought kit since after buying it 3 times, I have paid my dues
B) Weight one side just a little to get it to turn. Last time out on a 1/2A - 32 seconds IIRC.

Seriously. I can not see how if you follow Robs instructions, anyone can fail at a Deltie. I know that is probably irrelevant to this thread... but to others reading it in the future, perhaps not.

Mary painted my freebie Hawk for me. I've not flown it--it probably weighs a ton from the sealers and paint.

Hence:

Attached Thumbnails

     

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NAR# 94042
SAM# 0078

I don't see any airfoil on that wing.

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Bob Harrington
NAR #62740 L1
AMA #46042
CMASS & RIMRA Member

According to the instructions, airfoiling is optional for the Hawk, although it is recommended to round the fin edges.

Not that I know a darn thing about the subject... that is the point of this thread.

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My site: http://rocketry.gonnerman.org

Boost-gliders *will* glide with un-airfoiled, flat plate wings, but airfoiling the wings and (optionally) the horizontal stabilizer (or the small forward canard wing, on a canard glider) will improve the glider's performance. A boost-glider with flat-plate wings can be used as a "foul-weather B/G," on days when a better-gliding B/G with a lower sink rate might glide out of sight.

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None of these things are as critical as you may think. Not only do flat plate wings work (although not as well as airfoiled ones), but even symmetrical airfoils (those typically used in balsa fins; they produce zero lift at an angle of attack of 0 degrees) work well in boost-gliders and rocket gliders--they only need to be mounted at a slight angle to the glider's fuselage. (Aerobatic airplanes--model and full-size--often use symmetrical airfoil wings as well.) Also:

Please read the chapter about boost-gliders (B/Gs) and Rocket Gliders (RGs--he also explains about using symmetrical as well as flat-bottomed airfoils in these models) in G. Harry Stine's "Handbook of Model Rocketry" (and also see "Centuri TIR-24, Model Rocket Lifting Bodies," see: http://www.spacemodeling.org/jimz/tir-24.htm , http://www.spacemodeling.org/jimz/tr/tir-24.pdf , and http://sargrocket.org/documents/Res...turi/tir-24.pdf [these are three copies of the same--just two-page--Technical Information Report]), and:

"Estes Technical Report TR-4 Rear Engine Boost Gliders" (see: https://www.modelrockets.nl/downloa...t%20Gliders.pdf ) and "Estes Technical Report TR-7 Front Engine Boost Gliders" (see: http://www.ninfinger.org/rockets/EstesTR7.pdf ) are very helpful--and a later, revised Estes B/G publication can also be accessed here (see: https://estesrockets.com/wp-content...ost_Gliders.pdf [this is the new "Estes Educator TR-4 Model Rocket Technical Report Boost Gliders," which covers all--or nearly all--B/G and RG types], *and* https://www.google.com/search?q=Est...sclient=gws-wiz [which shows various old and new B/G and RG kits]). All of the Estes Technical Reports are also included in their "Classic Collection" (see: https://estesrockets.com/wp-content...ction_TR-TN.pdf ). Also:

Boost-gliders (B/Gs) separate the motor (or the motor pod, or an entire rocket in its own right [with parasite B/Gs]) from the glider portion of the model. Rocket gliders (RGs) don't separate *anything* in flight; what goes up glides back, as a single unit, including the spent motor or motors (clustered--and even staged--B/Gs have been built and flown [there is--or was--a clustered Edmonds B/G kit]; front motor models like the Estes Falcon are also easy to cluster or stage). As well:

The B/G & RG chapter in Stine's "Handbook of Model Rocketry," Centuri TIR-24, and the three Estes B/G and/or RG Technical Reports explain ^why^ and *how* boost-gliders and rocket gliders fly--and stably--in both flight modes ([1] vertical, rocket-powered ascent, and [2] the horizontal, un-powered glide back down to the ground), and how they transition from the first flight mode to the second one. None of these things are as complicated as they may sound (Stine even included a set of simple, basic B/G design rules in that chapter of his "Handbook of Model Rocketry"--the resulting model looks very much like the MPC--and later Quest--Flat Cat kit, which he designed [his Unicorn contest B/G was rather similar, but had a V-tail, see: http://www.ninfinger.org/rockets/Mo...02n06_03-70.pdf and https://www.rocketreviews.com/plang...0703153800.html ].) No one need "suck at gliders."

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All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

Also, ^here^ (see: http://www.ninfinger.org/rockets/ca...an/esttech.html & http://www.ninfinger.org/rockets/ca.../esttech12.html ) are the plans for the Sky Slash II front motor boost-glider. It is similar to the Estes Astron Falcon kit, but it has a larger wing area (and a flat, thicker sheet balsa fuselage [a scaled-down Sky Slash for 13 mm mini motors should also have high performance]); the Falcon kit's design was developed to use less sheet balsa than the Sky Slash II, yet have a high gliding performance (see: http://www.ninfinger.org/rockets/no...a/69est036.html & http://www.ninfinger.org/rockets/ca...73/73est28.html ), and:

The Semroc (originally AMROCS) Hawk boost-glider kit was/is similar to Estes' Falcon (see: https://www.rocketreviews.com/semro...ichielssen.html ^and^ https://plans.rocketshoppe.com/amro.../amr101-150.htm [this link is to scans of the AMROCS Hawk kit instructions--and its parts patterns]). The Estes Falcon kit instructions and parts patterns are *here* (see: http://www.spacemodeling.org/jimz/estes/k-13.pdf , http://www.spacemodeling.org/jimz/k-13.htm , and https://outerzone.co.uk/plan_details.asp?ID=12328 ). In addition:

Here (see: http://www.ninfinger.org/rockets/no...a/69est072.html ) is more boost-glider information, in the "Estes Model Rocket Manual" (the "yellow pages," beginning *here*: http://www.ninfinger.org/rockets/no...a/69est048.html ), in the 1969 Estes Catalog.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR