Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Work Bench > Building Techniques
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 04-09-2022, 07:21 AM
Bill's Avatar
Bill Bill is offline
I do not like Facebook
 
Join Date: Sep 2008
Location: North Tejas
Posts: 2,722
Default

Quote:
Originally Posted by rocket.aero
We have been entirely clear that the only motors allowed for use at the World Championships next year will be NAR certified motors from Estes and Aerotech. Additionally, those motors will be provided by the organizers.


Are you buying one big batch for consistency?

Are US contestants not allowed to bring their own?


Bill
__________________
It is well past time to Drill, Baby, Drill!

If your June, July, August and September was like this, you might just hate summer too...

Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...
Reply With Quote
  #22  
Old 04-09-2022, 08:56 AM
Gus's Avatar
Gus Gus is offline
7/21/61
 
Join Date: Sep 2005
Location: North of Detroit
Posts: 2,109
Default

Quote:
Originally Posted by Bill
Are you buying one big batch for consistency?

Are US contestants not allowed to bring their own?


Bill

Estes will be supplying one big batch for the contest.

Those motors will be provided to contestants by the contest at the contest.

Motors are marked as being contest-provided prior to being given to contestants.

Contestants will not be allowed to use their own motors.

This is the same as it has been done at all the FAI U.S. World Cup events for the last several years.
Reply With Quote
  #23  
Old 04-09-2022, 11:24 PM
Gus's Avatar
Gus Gus is offline
7/21/61
 
Join Date: Sep 2005
Location: North of Detroit
Posts: 2,109
Default

Quote:
Originally Posted by Ez2cDave
EXCEPT in "S7" ( Scale ), correct ?

Dave F.

Not correct.

ALL motors will be supplied by the contest.
Reply With Quote
  #24  
Old 04-11-2022, 06:00 PM
georgegassaway's Avatar
georgegassaway georgegassaway is offline
Contest, Sport, it's all good......
 
Join Date: Jul 2008
Location: West of Minneapolis, MN
Posts: 686
Default

So, back on track, here is a video of a C6 powered Superroc, being launched using a floating head piston, out of a 6 foot tower. The video goes to slo-mo for launch, but the audio does not, so never mind the audio. This was a test flight at home, to see if that model held together using that piston. It flew pretty well.

https://m.youtube.com/watch?v=rzWAm...eature=youtu.be

After all, all these posts about FH pistons, and most in this forum have not seen one work (or even fixed-head pistons).

Here is another test. B6 egglofter using a FH piston. To keep things aligned in the tower, the piston tube had two centering rings, the OD equal to the OD of the egg capsule. Once the model goes out of sight, nothing else to see, so no need to watch to the end. And once again, the audio is screwy.

https://m.youtube.com/watch?v=0DCDO...eature=youtu.be

The vertical camera angle, under the pad but a bit to the side, usually upwind (avoid smoke), is a great way to get video for test flying. Sometimes things go screwy that you'll never see real-time by eye, or even in a side view video.
__________________
Contest flying, Sport flying, it's all good.....
NAR# 18723 NAR.org
GeorgesRockets.com
Reply With Quote
  #25  
Old 04-11-2022, 06:28 PM
Gus's Avatar
Gus Gus is offline
7/21/61
 
Join Date: Sep 2005
Location: North of Detroit
Posts: 2,109
Default

George,

Nice videos. And both demonstrate what I indicated back in post #9, that the rockets leave the piston almost immediately after the aft end of the tube hits the piston head. Piston tubes aren't anywhere near leaving the tower before the rocket has already departed.

Not that this discounts the beneficial effect of the the pistons. Just that floating and fixed heads aren't very different in terms of the extra impulse they impart.
Reply With Quote
  #26  
Old 04-11-2022, 06:35 PM
Ez2cDave's Avatar
Ez2cDave Ez2cDave is offline
Master Modeler
 
Join Date: Mar 2005
Location: Raleigh, NC Area
Posts: 1,380
Default

Back on topic . . .

It will be interesting to see how the final standings end up at the WSMC, with all competitors using the same motors, whether a piston launcher is employed or not.

It should be a good indicator of how the different designs perform, on a level playing field.

I predict that the advantage will go to Team USA, since our competitors have the most experience flying USA-made motors, especially the Estes BP motors.

Question . . . What about igniters ?

Are competitors required to use the igniters that are supplied with motors ?
Can they substitute igniters ?
Are home-made igniters allowed ?

Dave F.
__________________
"Failure Is Not An Option . . . Adapt & Overcome ! "

NAR # 26128 L2
TRIPOLI # 517 L2 ( inactive, at present )

Last edited by Ez2cDave : 04-11-2022 at 07:25 PM.
Reply With Quote
  #27  
Old 04-11-2022, 10:33 PM
rocket.aero rocket.aero is offline
Craftsman
 
Join Date: Mar 2008
Posts: 151
Default

Quote:
Originally Posted by Ez2cDave

Are competitors required to use the igniters that are supplied with motors ?
Can they substitute igniters ?
Are home-made igniters allowed ?

Dave F.


Competitors are free to use their own igniters, subject to the limitations of the NAR and FAI Safety Codes. As most of them use bare nichrome I suspect that they will find the Estes StarTech igniters a revelation.

We know from experience that Estes igniters work well with fixed-head pistons.
Reply With Quote
  #28  
Old 04-11-2022, 10:40 PM
Ez2cDave's Avatar
Ez2cDave Ez2cDave is offline
Master Modeler
 
Join Date: Mar 2005
Location: Raleigh, NC Area
Posts: 1,380
Default

Quote:
Originally Posted by rocket.aero
Competitors are free to use their own igniters, subject to the limitations of the NAR and FAI Safety Codes. As most of them use bare nichrome I suspect that they will find the Estes StarTech igniters a revelation.

We know from experience that Estes igniters work well with fixed-head pistons.


Actually, I was thinking about clusters in S7 ( Scale ).

Dave F.
__________________
"Failure Is Not An Option . . . Adapt & Overcome ! "

NAR # 26128 L2
TRIPOLI # 517 L2 ( inactive, at present )
Reply With Quote
  #29  
Old 04-11-2022, 10:47 PM
rocket.aero rocket.aero is offline
Craftsman
 
Join Date: Mar 2008
Posts: 151
Default

Quote:
Originally Posted by Ez2cDave
Actually, I was thinking about clusters in S7 ( Scale ).


Same answer: Estes igniters, AT igniters, and traditional cluster techniques.

Our friends from overseas are experienced flyers, and most of the top-tier S7 competitors are already using Aerotech motors.
Reply With Quote
  #30  
Old 04-12-2022, 12:35 AM
georgegassaway's Avatar
georgegassaway georgegassaway is offline
Contest, Sport, it's all good......
 
Join Date: Jul 2008
Location: West of Minneapolis, MN
Posts: 686
Default

Quote:
Originally Posted by Gus
Not that this discounts the beneficial effect of the the pistons. Just that floating and fixed heads aren't very different in terms of the extra impulse they impart.

Some might note that in the B6 eggloft video, you can see micro-clips falling down inside the tower, after the piston begins to move up and the clips slide off the external wires of the ignitor as intended. I never got around to trying to use internal ignition in a Floating Head Piston (Well, I could not devise a good way to do that, without being a more precision and time consuming prep than I felt comfortable doing, over and over reliably). And as a result, there's a bit of pressure loss as a result (slight gap between engine and tube due to ignitor wire thickness up along the side).

While my Teammate Chan Stevens has his system nailed down for a floating piston head with internal electrical connectors. But he has to do a very precise and unforgiving prep to make it work, without accidentally unplugging the internal leads to the connectors in the piston head during the process. He does it well.

By contrast, with fixed head pistons, since around 1977 or so I'd been using a very successful internal ignition electrical system that many people copied, later vastly improved years later by SIP sockets (though that was also something that a lot of people arrived at independently, too).
__________________
Contest flying, Sport flying, it's all good.....
NAR# 18723 NAR.org
GeorgesRockets.com
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 10:41 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe 1998-2022