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Tuesday, July 9, 2019

Saturn V Fairing Melts? BIG Tip

I've already seen a few Estes Saturn V launches celebrating the 50th Anniversary of the Moon Landing. Before launching, take a moment to be sure your model is
ABOVE THE BLAST DEFLECTOR -

From the Facebook page - Model Rocketry Fanatics:
Stepen Fitton posted:
"This is after only 2 flights on D12s. Any ideas for building my 2nd Saturn V kit to keep the vacuform fin fairings from melting?

 Vin Sauriol replied: 
"How close was it to the blast plate?"
"1-2 more inches up next time. Anything I send is 4” from the plate."

 G. Harry Stine would say: "When in doubt, follow the instructions."
These pictures are from the Estes instructions:






The top edge of the tape should be 8" from the blast deflector. The lower lug and standoff are already glued above the low end of the rocket. The tape (use a few wraps, the rocket is heavy) should hold the rocket far enough above the blast deflector.
I know the excitement of launching your BIG rocket the first time, nobody carries the instructions to the launch site.

On the right is Mark Stephens Saturn V. Without a blast deflector, this shows what can happen using a J engine!

If you have ever watched a slow motion launch video, you'll see the engine blast bounce and reflect back up to the bottom of your rocket. Some of my rockets have charred fins.
The Saturn V is heavy and much slower off the launcher, a moment longer subjected to the heat flashback.

I made some card stock crescents that strengthen and could help prevent the melting of the thin plastic.
For Part One - CLICK HERE 
For Part Two - CLICK HERE
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6 comments:

  1. The Rocket N00bJuly 9, 2019 at 1:42 PM

    I've gotten much better at getting rockets back looking the way they did before I put them on the pad. Raising them a little more than I used to is a big part of that.

    Our club uses standoffs - usually either clothes pins or used motor casings. I guess a lot of clubs probably do the same. But they can be in pretty bad shape. I often bring a couple new clothes pins just in case.

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    1. Chris MichielssenJuly 9, 2019 at 5:45 PM

      Hi Daniel,
      Sometimes at club launches I'll notice a first timer not using a standoff, or raising the model over a foot up the launch rod.

      Delete
  2. metalhead1986July 9, 2019 at 2:53 PM

    Chris - would the shape of Odd'l blast deflector help with this?

    I have to be honest and say I've never noticed that in the instructions. I haven't had this issue, even with high power rockets, but I will certainly pay attention now.

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    Replies
    1. Chris MichielssenJuly 9, 2019 at 5:43 PM

      Hi Metal,
      The Odd'l Blast Deflector (or any angled deflector) would help. That Saturn V fairing plastic is thin, it wouldn't take much to melt it.
      You'll see charred fins on minimum diameter models where the fins trail beyond the back of the body tube.

      Delete
  3. PhillJuly 13, 2019 at 2:24 PM

    Glue a 2" launch lug to the inside of the BT101 (far enough up that it doesn't foul the display nozzle assy. Then, on the pad, you can slide a 10" dowel (or bamboo skewer etc) in it - instant pad leg! The dowel will slide out on launch and, if it doesn't, it won't foul the flight characteristics

    ReplyDelete
    Replies
    1. Chris MichielssenJuly 14, 2019 at 12:33 AM

      Hi Phill,
      Yep, that would work! Great idea. The Estes instructions show masking tape around the launch rod. It'd take a few wraps of tape to hold up this heavy rocket.

      Delete