Model Rocket Help
January 1, 2016 7:33 PM   Subscribe

My son got a model rocket kit for christmas, he put everything together and it all seems correct, but, none of the 3 flights we have taken have reached optimal height.

So, we've watched some Youtube videos and it appears we are doing everything correctly but, his rockets only go about 30 feet (it's supposed to go to 200 - 300 feet. , then dive, and the parachute ejection charge happens while it's on the ground. According to what we've read, it's only one stage but it is supposed to keep rising after the initial blast. Does anyone have any ideas why it's stalling out?
posted by trbrts to Sports, Hobbies, & Recreation (11 answers total) 1 user marked this as a favorite
 
Maybe there is something wrong with the engines that you got - maybe they were old or wet or something? Sounds like they are not burning properly.
posted by Mid at 7:35 PM on January 1, 2016 [1 favorite]


Make sure the rocket is sliding freely on the rod off the launch pad. Run some sandpaper over the metal rod to make sure it's smooth.
posted by frontmn23 at 8:21 PM on January 1, 2016 [1 favorite]


Following up on frontmn23, also make sure that if the metal rod on the launch pad is made of 2+ parts that there isn't a seam it can get stuck on where the parts meet (i.e., sand that really well so it's smooth at joints, if there are any).

OP, could you post the model?
posted by Brian Puccio at 9:44 PM on January 1, 2016


Double check the specs on the engines, that sounds like you got the wrong power for the kit.
posted by sammyo at 9:45 PM on January 1, 2016


Paint and sand it. Make it smooth but don't weigh it down with too much paint.

Don't put too much wadding in it.

As others have said, check the launch rod. Make sure the tube on the rocket that the rod goes into is perfectly aligned with the direction of travel.

Make sure the ignitor isn't in too tight.

Buy new engines. Check the rating on them because the optimal height might be for a higher rated engine than you have.

Basically you want it light and smooth. No extra weight, no extra friction.
posted by bondcliff at 7:19 AM on January 2, 2016


Re: binding on the launch rod

Lubrication is as important as smoothness with metal. The merest trace of 3-in1 oil.
posted by SemiSalt at 8:43 AM on January 2, 2016


Instead of 3-in-1, try a tiny bit of graphite or talc. Oils collect dust and get gummy (and rocket exhaust is basically dust).

Definitely post which engine you're using and the model.
posted by plinth at 1:54 PM on January 2, 2016 [1 favorite]


- Make sure your launch lug (the tube the launch rod goes through) is straight and unobstructed (e.g. by paint, etc).
- Make sure you got the correct engines. What engines are you using? Which rocket did you build?
- Are your fins mounted straight?

Photos of the build and the links to the launch videos would be very helpful in diagnosing the issue.
posted by jeffamaphone at 1:57 PM on January 2, 2016


It really sounds like you have the wrong engine - the rocket is basically too heavy for the engine you are using. For instance - if you are using an 'A' engine - you probably need a 'B' or a 'C' to get to a decent height. Memail me if you have questions.
posted by nightwood at 7:43 PM on January 2, 2016


Sometimes the pack-in rocket engines are much weaker than the typical ones. Try buying fresh ones.
posted by rikschell at 5:35 AM on January 3, 2016


No photos / videos? I am disappoint.
posted by jeffamaphone at 8:20 PM on January 4, 2016


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