Make your own free website on Tripod.com

General Competition Tips

 

Competition Vendors

NAR Certified Motors

 

 

 

 

Event Tip Menu

 

 

 

Set Duration

B Streamer Duration Multi-Round

B Helicopter Duration

C Payload Altitude

D Boost Glide Duration

D Egg Lofting Altitude

Research & Development

Scale

 

 

 

 


 

D Egg Lofting Altitude

 

Note that for NARAM-50, the Egg Lofting Altitude event for D engine class.

Egg Lofting Altitude combines the challenge of flying a model containing a Grade A Large egg (and recovering it intact), with trying to reach the highest altitude possible.

Egg Lofting Altitude models can be staged. If the egg is not returned or is damaged (cracked, broken, etc.), the flight is disqualified.
You can NOT catch the egg lofter, it must be allowed to land naturally.

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

Scoring - For Egg Lofting Altitude, the scoring is best SINGLE qualified flight’s altitude (egg returned intact), of the two flights allowed.

Design considerations - To balance the ability to fly a model containing an egg as high as possible with the need to return it safely. Compromises of low drag and low model weight, protecting the egg (capsule and cushioning), and deploying a chute that is not big enough for a gentle landing versus too big a chute which can jam inside the tube or let the model drift away unrecovered.

There are many engine choices available for this event. The best-flying will tend to be 18mm composite engines, such as the D10 and D21. There is also the D13 reload, though that adds a bit of extra mass and the cost of the reload casing will hurt if you lose the model. Also, the higher the thrust of the engine, the stronger the model will need to be to not shred its fins off. A model flying on 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 was not 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 took them so long to land that some of the best models drifted into the woods. So, this may be an issue for 2008 as well.

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

General Tips for Egg Lofting Altitude

An egg lofter with a long tapered conical shroud is OK for egg loft altitude. The Two Minute Egg plan is such a model, and both ASP and QCR have similar contest oriented kits.

A straight body-tube 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 Egg Lofter kit is a reasonable C egg loft 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" egg lofter 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 egg loft 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 the model to fly straight and true. Work towards attaching all of the fins so they are straight and parallel to the body. This should translate to a straight boost, with minimal wobbling that would hurt the altitude.

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

Egg Capsule - Pratt Hobbies makes an excellent vacuformed egg capsule (the old CMR capsule). Some companies like ASP and QCR carry that capsule. Apogee also has their own vacuformed egg capsule.

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

Padding - Use foam or some other flexible material to try to cushion the egg so it will not get cracked. My favorite basic cushioning is to get hold of a foam egg carton and cut out the four corner "cups" as they fit the egg pretty well. I add other thin foam padding as well. The egg needs to be padded enough that it can't rattle, but don't pack it so tight that it's under pressure when loaded in the capsule. If you are using a plastic capsule, don't bother with putting the egg inside of a plastic bag....if the egg breaks you can just clean the capsule with water, without any damage.

Parachute - In Egg Lofting 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 Egg Lofting 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 egg lofting 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 can actually absorb the shock of deployment, given the weight involved with egg lofters. 1/8" elastic works very well for that purpose, but is not ideal to attach directly to the body tube. Many competitors prefer to use a length of 100 pound grade Kevlar cord to attach to the body tube (especially for mounting inside), then tie the elastic shock cord to the other end of the Kevlar cord. The 2-Minute Egg plan mentions using wire cable in a similar way to link elastic to the model. This method was used before Kevlar came into use for contest models, so 100 pound Kevlar can be used rather than wire cable for the 2-Minute Egg. Unfortunately, the very hot ejection charge of a D12 can burn a 100 pound Kevlar shock cord if it is attached within the first 3" or so of the ejection end of the engine, so for D12 models the Kevlar cord needs to be mounted away from the heat blast or 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, is 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 Egg Lofting 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 Egg Lofting Altitude, not really recommended.

return to top


Model Plans & Kits

Designer

Notes

ASP - Egg Lofter Kits (various) & Pratt Egg Capsules

ASP (Aerospace Specialty Products), Andy Jackson

Good competitive kits

QCR - "Easter Egg" & "Pratt” capsule Kits for 18mm & 24mm engines.

QCR - Qualified Competition Rockets, Ken Brown

Good competitive kits

C & D Egg Lofter Plans - straight tube type

Plans by George Gassaway

Competitive plans for C and D power, minimal details

Prangroc plan straight tube type (NAR website)

Plan by Mike Burzynski

A very old straight body tube design, showing how plastic Easter Egg capsules could be used. Modern-day suggestion would be to use BT-20/18mm body tube and Pratt Egg capsules

E Dual Egg Lofter plan straight tube type (NAR website)

Plan by Glenn Feveryear

The basic 24mm body of this dual egg loft plan can be used with any practical egg capsule for D Egg Lofting Altitude.

2-Minute Egg Plans  shroud type (NAR website)

Plan by George Gassaway

Good competitive plan for C power (shroud)

Elite Egg Lofter kit by Custom Rockets

Custom Rockets

A reasonable model for C Egg Lofting Altitude

Shecter Rockets Egg Lofter kits (PDF list)

Fred Shecter

Straight tube (18mm) egg lofter kit with Easter Egg type capsule. Fins shown seem much bigger than necessary.

QUEST - "Courier" sport egg lofter kit

QUEST Aerospace

Not too competitive, but flyable on a C6-3. Available from various Quest dealers, including Apogee

TIPS - Selecting Parachutes for Egg Lofting

by Andy Jackson, on the ASP (Aerospace Specialty Products) website

Great article on considering what size or type of parachutes to use in egg lofting competition, whether for duration or altitude. Also tips on chute packing.


return to top

Last Updated 12/09/2008