NARAM-50 Event Tips Pages (draft)

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General Competition Tips	Contest Certified Engines	Vendors for contest rockets	Return to NARAM-50 Home Page
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Set Duration	B Streamer Dur. Multi-Round	B Helicopter Duration	C Payload Altitude
D Boost Glide Duration	D Eggloft Altitude	Research & Development	SCALE

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D Eggloft Altitude

Note that for NARAM-50, the Eggloft Altitude event forD engine class.

Eggloft Altitude combines the challenge of flying a modelcontaining a Grade A Large egg (and recovering it intact), withtrying to reach the highest altitude possible.

Eggloft Altitude models can be staged. If the egg is not returnedor is damaged (cracked, broken, etc.), the flight isdisqualified.
You can NOT catch the egglofter, it must be allowed to landnaturally.

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

Scoring - For Eggloft Altitude, the scoring is best SINGLEqualified flight 's altitude (egg returned intact), of the twoflights allowed.

Design considerations - To balance the ability to fly amodel containing an egg as high as possible with the need to returnit safely. Compromises of low drag and low model weight, protectingthe egg (capsule and cushioning), and deploying a chute that is notbig enough for a gentle landing versus too big a chute which can jaminside the tube or let the model drift away unrecovered.

There are many engine choices available for this event. Thebest-flying will tend to be 18mm composite engines, such as the D10and D21. There is also the D13 reload, though that adds a bit ofextra mass and the cost of the reload casing will hurt if you losethe model. Also, the higher the thrust of the engine, the strongerthe model will need to be to not shred its fins off. A model flyingon a D21 needs to be a lot stronger than one flying on a D10.

The classic old reliable way to go is to use a D12 engine.

This event was held at the very same site at NARAM-46 in 2004.Some of the better-flying models drifted off into the wood. It wasnot very windy, simply it was an issue of models flying so high up,and needing to land slowly enough not to break the egg, that it tookthem so long to land that some of the best models drifted into thewoods. So, this may be an issue for 2008 as well.

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

General Tips for Eggloft Altitude

An egglofter with a long tapered conical shroud is OK for eggloft altitude. The Two Minute Egg plan is such a model, and both ASP and QCR have similar contest oriented kits. A straight body-tubed model with capsule on top also is competitive. Such as an all-18mm body, or all 24mm body. QCR has kits of this type. Custom Rockets' Elite Egglofter kit is a reasonable C eggloft altitude model. Some competitors feel the straight body type flies higher, while some prefer shrouded bodies. Straight bodies have simplicity going for them, while shrouded bodies have reliability in their favor due to the recovery system storage space and room for tracking powder. A straight body tube with a larger diameter, such as 1.3" to 1.65" diameter (BT-55, 35mm, BT-60) can be used. The model will be draggier and usually heavier, of course, and therefore at a competitive disadvantage. The Quest "Courier" egglofter kit can be used with 18mm composite D engines or on a D12 if built with a 24mm engine mount. Some regular models you might already have can be adapted to fly as an eggloft altitude model by replacing the nose cone with a capsule. But they cannot be too heavy or they just will not fly safely enough with the added weight of an egg.

Straight tube (Prangroc)

Conical Shroud (2 Minute Egg)

Build well - A key to any altitude event is building themodel to fly straight and true. Work towards attaching all of thefins so they are straight and parallel to the body. This shouldtranslate to a straight boost, with minimal wobbling that would hurtthe altitude.

And the faster the model boosts, the more strongly it needs to bebuilt, to avoid shredding the fins at high speed.

Egg Capsule - PrattHobbies makes an excellent vac-formed egg capsule (the old CMRcapsule). Some companies like ASPand QCR carry thatcapsule. Apogee also hastheir own vac-formed egg capsule.

Another capsule sometimes used is a plastic Easter Egg, of a sizethat is just a little bigger than an egg. Such capsules use two "longhalves" from two 1.75" diameter Easter eggs, rather than one plasticegg due to the short half with a flange sticking out, as the flangelimits the inside diameter too much. Easter Egg capsules that smallcan be hard for the eggs to fit in and be safely cushioned, however."Grade A Large" eggs tend to vary significantly in diameters, soEaster Egg capsules are somewhat risky. It's best not to risk using atoo-cramped capsule.

Padding - Use foam or some other flexible material to tryto cushion the egg so it will not get cracked. My favorite basiccushioning is to get hold of a foam egg carton and cut out the fourcorner "cups" as they fit the egg pretty well. I add other thin foampadding as well. The egg needs to be padded enough that it can'trattle, but don't pack it so tight that it's under pressure whenloaded in the capsule. If you are using a plastic capsule, don'tbother with putting the egg inside of a plastic bag....if the eggbreaks you can just clean the capsule with water, without anydamage.

Parachute - In Eggloft Altitude, the trick is to balance using a chute size that will not land so hard that the egg might crack, versus using a bigger chute that may let the model drift too far off to recover. A ballpark suggestion for decently padded eggs in a light model is to use a 12" to 14" parachute. For eggloft Altitude, using a commercial type chute canopy is usually OK, you don't want to use a canopy so thin that it rips easily. Andy Jackson of ASP (Aerospace Specialty Products) has written a great article on considering what size or type of parachutes to use in egglofting competition, whether for duration or altitude. It also has tips on chute packing. Shroud lines can be "button and carpet thread", which is what most manufacturers use. To avoid the lines pulling loose from the parachute under stress, the shroud lines can be attached to run over the top of the chute as shown at right. Cut-up band-aid pieces can make for very sticky yet flexible shroud line tabs.

click on thumbnail

Shock Cords - It is useful to use a shock cord that canactually absorb the shock of deployment , given the weight involvedwith egglofters. 1/8" elastic works very well for that purpose, butis not ideal to attach directly to the body tube. Many competitorsprefer to use a length of 100 pound grade Kevlar cord to attach tothe body tube (especially for mounting inside), then tie the elasticshock cord to the other end of the Kevlar cord. The 2-Minute Egg planmentions using wire cable in a similar way to link elastic to themodel. This method was used before Kevlar came into use for contestmodels, so 100 pound Kevlar can be used rather than wire cable forthe 2-Minute Egg. Unfortunately, the very hot ejection charge of aD12 can burn a 100 pound kevlar shock cord if it is attached withinthe first 3" or so of the ejection end of the engine, so for D12models the kevlar cord needs to be mounted away from the heat blastor protected from the heat.

Tracking Powder - It is highly recommended to use tracking powder in your model. This produces a small "cloud" at ejection which the tracking crew looks for. Without tracking powder, it is not likely your model will get tracked. Dry Tempera paint, or a fine powdered Fluorescent Dye, are often used for tracking powder.Some contestants used to rely on powdered chalk, but it is clumpy and does not really produce much of a tracking cloud for the volume/weight of the powder. Red is a good color choice for tracking powder, though some like to use black if there is a high overcast or hazy "white" sky. Fellow competitors are often willing to share tracking powder. Here's a good way to install tracking powder. After installing wadding, pack the parachute and shock cord into the model, and push them down into the tube to leave room for the tracking powder in the upper part of the tube. Use a piece of wadding or plain paper to make up a long narrow "cup" than will easily slide inside the body tube. Press that cup into the tube, then pour in the tracking powder to fill the cup. About 1" or so depth of powder is a good ballpark. Using tracking powder can require greater forces to expel everything out of the body, which sometimes results in the engine kicking out instead (however, the cup method reduces this problem a bit compared to just dumping powder into the tube). Make sure the engine is secured in the rocket extra-tight. Some people like to attach the fins a bit above the bottom of the body tube so they can apply a "collar" wrap of tape to the bottom of the tube and the engine. This helps prevent the engine from ejecting.

click on thumbnail Above: Example of a tracking powder cloud, having ejected from a model that was stuck in its launcher.

Engine recommendations for D Eggloft Altitude	D10-7 (light low-drag 18mm models)
or	D21-7 (light low-drag STRONG 18mm models)
or	D13-7 reload (light low drag strong 18mm models)
or	D13-10 reload (light low drag strong 18mm models )
or	D12-3 (heavy and/or draggy model)
or	D12-5 (low drag lightweight model)
or	D12-7 (high performance low drag lightweight model if not too windy)
or	C6-0/C6-7 staged (Low drag lightweight model if not too windy)*
	* Staging C's is a fairly high risk way to fly D Eggloft Altitude, not really recommended.

 Last Updated  5/26/2008