BRB Regional Meet - 1

November 15, 2008

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1/2A Boost Glide Duration
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*** NOTE: Use this link to go to Plans and Instructions for the Boost Glider kit ***

1/2A Boost Glide


Boost Glide combines the challenge of building and flying a glider which can boost relatively well (and hold together) on rocket power, and transition to a long gliding flight.

Boost Gliders often use a pop-pod, or sometimes are attached to the side of a larger rocket (parasite) for the vertical boost portion of the flight, then separate for the glide back to earth. If the entry kicks out an engine, the engine needs to have a streamer on it. A free-falling engine casing will be DQ'ed. The glider portion is timed. The glider must be returned for one of the two flights allowed.

Flex-wing (Rogallo/hang glider) type gliders are not allowed.

For the full rules for this event, please see the Boost Glide Rules on the NAR web page.

Scoring - For Boost Glide, the scoring is the sum of the times from the two flights allowed, with at least one of those flights having the glider returned.

Design considerations - Trade-offs of high glider performance, visibility, surviving rocket boost, and shooting for a reasonable boost altitude.

It's not very practical to modify the proverbial 49 cent balsa glider to fly this event since the wings probably would rip off. Best to go with a kit such as those below, or a plan. With experience, you might later develop a knack for designing your own gliders, but it's best to learn from a proven design first.

A list of plans and kits is included further down on this page.

Pop-Pods - Nearly all B/G's use pop-pods. These are short finless bodies that have the engine, launch lugs, and usually a streamer for recovery. They attach to the glider using some sort of hook system, so they carry the glider up during boost then at ejection kick backwards to separate from the glider.

Spooler Pop-Pods - Sometimes, the shock cord or streamer on a pop-pod gets hung up on the glider, causing a tangled "Red Baron" descent to the ground. The "Spooler" pop-pod design eliminates shock cords, and delays streamer deployment until the pod has left the glider. It works by having the streamer rolled up (spooled) inside so it cannot deploy until after the nose section has been ejected off (the nose tumbling down safely, usually painted a fluorescent color to aid in finding it). Click here for a drawing that shows the Spooler pod design for 13mm engines.

Pod hooks - Various kits and plans show different types of pod hook or pod attachment methods. Unless the glider is somewhat unique, you can usually use your favorite pod hook method on any given boost glider plan as long as you maintain the pylon height between the top of the fuselage and the pod tube (on most gliders, the pylon height is 1/2").

CMR Manta Hooks - The old CMR Manta kit used a hook system that proved to be simple and mostly universal. It is easily duplicated by using spruce for the hooks and thin plywood or G10 fiberglass sheet for the side plates. Click here for a drawing showing more details than at right.

Apogee Universal Glider Hooks - A single cast part design which has a hook and a slot, which fits with an identical cast hook and slot part (see drawing at right). One is glued to the pod, and one is glued to the glider (these were originally developed for the Maxima glider kits). Any glider can fit any pod, since the hooks are all identical. Click here for a drawing showing more details than at right. The hooks are sold by Apogee.

Building Gliders - Ed LaCroix created some fantastic instructions for the Maxima A Boost Glider kit, from the time when Ed owned and ran Apogee. The kits are gone now, but the plans and instructions live on (a nearly 1 meg pdf file, well worth the download). The instructions are so in-depth that they are a must-read for anyone wanting to learn more on how to build, trim, and fly rocket boosted gliders of any kind. And the Maxima A also is a good contest model. Click here for a GIF file showing the wing and tail templates more clearly, and to exact size.

Kevin Wickart wrote a nice short article on how to do quick and easy airfoils, on the WOOSH section's website. Click here to read it.

A VERY nice sanding block, useful for gliders, helicopters, and any rocket really, is an all-metal 2-piece clamp-type sanding block made by Red Devil, carried by most Ace Hardware stores (look near where they stock sandpaper). It has a 1/8" foam rubber backing sheet, which should be removed since it allows rounding things too easily in 3-D when you usually want to shape in 2-D at a given time (as with a wing). So, remove the rubberized portion. That sanding block holds a 4.5 x 5.5" sheet of sandpaper (quarter of a 9 x 11" sheet), with a 3.5 x 4.5" sanding surface area on the block. This works far better in most cases than a narrow sanding block. Of course, the wings (or fins) should be shaped and finished before they are glued to the fuselage or model.

When doing very rough shaping for wings, 80 to 120 grit sandpaper is good for grinding off a lot of wood in a short time. Don't over-do it though by sanding off too much. Next use a finer grit like 180 to 220 for finer shaping. Beyond that, 280/320 paper, is sort of a cross between final shaping and setting up for a final finish. A final finish for bare balsa is sanding with 400 grit paper. Get the "black" type wet or dry sandpaper, it sands better and lasts longer than the reddish types. If you use any clear dope, use 320 to 400 grit paper before and after.

Glider Finish - Never use paint on a contest type glider. For newer fliers, no finish is usually fine. You don 't want to weigh the model down too much and maybe having warpage problems. If you want to improve the finish, use some thinned clear dope in one or two light coats, sanding before and after with 240 and 400 grit sandpaper. The idea it not to add weight or cause the wood parts to warp. Some fliers like to use a Japanese tissue finish, but that is more for experts and to an extent is overkill for A B/G's.

Coloring - OK, so bare balsa (even with clear dope) is not easy to see in the air or on the ground. Use a large black magic marker to color the bottom of the wing and tail surfaces black, as black shows up against the sky pretty well. Use a large red or orange magic marker to color the top surfaces. If you can find true fluorescent markers (not to be confused with wimpy fluorescent highlighters), an orange or red/magenta fluorescent color is highly recommended.

Glide trimming - It is an understatement to say that it is very important to trim the glider to glide properly. It's not easy to describe just how to do so.

One mostly universal tip is to have the tail of the glider and the wing to NOT be parallel to each other (there should be slight postitive incidence). There ought to be a little bit of "up elevator" angle in the tail, relative to the wing, to make the nose pull up a bit. Some plans/kits may be quite specific, and in those cases go with what they say. Note that free flight model airplane experts sometimes prefer zero incidence, but they are deeply experienced (usually) to have just the right touch and experience to get away with it.

The above being said, one of the simple ways to achieve slight up elevator effect (without adding too much) is to build the model zero-zero (wing and stabilizer parallel to each other), then warp the trailing edge of the stabilizer up. Make sure that the fuselage itself is not warped "down" - if it is warped at all, better to be warped "up" relative to the wing and stabilizer.

Here are a few links for trimming tips from a number of different sources:

Estes Boost Glider Technical Report, written by Tom Beach (pdf file from Estes Educator website). An excellent article with many illustrations, that cover a wide range of areas involving Boost Gliders and Rocket Gliders, including trimming. HIGHLY RECOMMENDED.

Kevin McKiou's Basics of Design and Trimming of B/G's and R/G's. Items 1 thru 5 are useful only if you are designing your own, or modifying an existing plan/kit. Items 6 thru 9 are useful for trimming gliders for optimum glide performance.

Again, Ed LaCroix's instructions for the Maxima A Boost Glider has trimming tips.

Hand Launch Glider trimming tips for beginners, from a British Free Flight model airplane site. The latter portions about hard throws (necessary for contest HL gliders) is not too relevant for rocket boosted gliders (since the F/F HL glider flyers's hard upward throws are their equivalents to our rocket "boosts"). Note the basic glide trim info and illustrations at the top of the page.

Launching - Set up the glider on the pad so that it faces into the wind. This means the wing bottom faces upwind, and the wing top faces downwind. Actually the dihedral effect will usually try to make the glider face that way.

Apply a flag of masking tape to the launch rod, so the flag holds the pop-pod high enough for the glider tail to not be touching the bottom of the launcher. Some people prefer to make their own glider launcher that has the launch rod mounted onto a 3/8" or 1/2" dowel, so that the whole rod can be used for guidance.

A classic launch problem is for the micro-clips to fall at ignition to grab onto the glider wing or tail, causing damage or even disaster. Some prefer to tape the clips to the rod so they can't fall, which is effective but a bit messy. Others like to use an umbilical approach. They arrange for a separate launch rod, dowel, or other structure to hold the micro clip wires away from the glider, so that when the clips fall they will not fall straight down, but will swing away in an arc from the glider. A simple umbilical is to use a piece of 1/4 x 1/4 spruce 18" long or so, and cut the bottom at a very sharp angle that is about 30 degrees from vertical. Then glue a launch lug to the angled part. That way, the spruce umbilical can be slipped over the launch rod, umbilical angled at 30 degrees from the rod, ready for the micro-clips to be attached to it. Put your name on it, since the next person to use that pad will probably want to remove your umbilical.

More Information:

Engine recommendation for 1/2A Boost Glide:


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Model Plans & Kits



Rocky Mountain Canary II plan, (NAR website)

Plan by Bruce Carey

The wing should be made using 1/8" balsa, to be strong enough for A power

Turnup plan, (NAR website)

Plan by Phil Slaymaker

A design that has been popular in recent years

Big Fish N' Chips plan

Plan by George Gassaway

1/2A & A design, wing should be 1/8" for A power.

Deltie Boost Glider Kit (13mm) from Edmonds Aerospace

Kit designed by Rob Edmonds of Edmonds Aerospace

Easy to build and reliable kit.

Ivee2G Boost Glider Kit (13mm) from Edmonds Aerospace

Kit by Rob Edmonds of Edmonds Aerospace

Basic competition-style boost-glider. Not currently on Edmonds' site, try Edmonds dealers including BMS and ASP.

QCR - "Neverloop" B/G kit series by Ken Brown

Kits by Ken Brown - QCR - Qualified Competition Rockets

Various B/G's designed for contest flying. See QCR's website.

Maxima A B/G plan (former Apogee kit)
    1 meg pdf file

Basic design by George Gassaway, refined and with great instructions by Ed LaCroix.

Competitive plan, plus detailed info on building/flying B/G's. Also get the wing and tail templates

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 Last Updated   9/10/2007