Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Work Bench > Vendors
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 10-30-2011, 02:45 PM
mwtoelle's Avatar
mwtoelle mwtoelle is offline
Flying since 1977
 
Join Date: Oct 2010
Location: Middle TN
Posts: 452
Default

Quote:
Originally Posted by CPMcGraw
(snip)
Haven't simulated a Cherokee-D yet, but I expect better lift-off numbers. This engine should not be viewed as a serious BOOST engine for heavier designs; rather as a higher-performance "D" for light designs (3FNC and 4FNC variety).

Early or late production on the Cherokee-D? A late production semi-clone that I built back in 1994 drifted out of sight after a successful flight on an Estes E15-8. However, an Estes E motor of any description will require some nose weight. I am surprised that you did not simulate the old Estes Omega with an E12-0/E12-8 combo. If you really want to fly heavy models on black powder motors, I think that you would need a core or semi-core burning motor.
__________________
'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373
Reply With Quote
  #22  
Old 10-30-2011, 05:53 PM
Jerry Irvine's Avatar
Jerry Irvine Jerry Irvine is offline
Freeform rocketry advocate.
 
Join Date: Jan 2008
Location: Claremont, CA "The intellectual capitol of the world."-WSJ
Posts: 3,780
Default

Quote:
Originally Posted by CPMcGraw
Using the new graph, as Jerry indicated, the engine is "soft". It appears great, once the model is airborne, but getting off the ground it doesn't have a lot of "oomph" when used in a design that weighs in over 13 oz loaded.

I also tried it out in the SEMROC SLS Laser-X...

Altitude -- 554'
Deployment V -- 4 FPS
Rod length -- 60" (took 49")

This is a 12.5 oz design loaded, and shows great flight numbers, but lousy take-off numbers.
I have strongly suggested Estes upgrade to 1/4" x 48" rods (USR standard) and forsake 3/16" going forward. The AT by E motors need a stiffer rod and the Estes E motors need a longer rod due to low take-off speeds. These E motors should be considered to have a max liftoff weight of a pound or less, and better if between 1/2 and 3/4 pound. I would say the MLOW of a D12 is 30-50% higher than an E12.

Counter-intuitive but true.

Jerry
Reply With Quote
  #23  
Old 10-30-2011, 08:14 PM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,357
Default

First simulations with a Cherokee DD...

Simulation 1: E12-0/E12-8......2709'......Dv 16 FPS......60" x 1/4" (45" required)

Simulation 2: D12-0/E12-8......2225'......Dv 8 FPS.......60" x 1/4" (47" required)

Simulation 3: E12-0/D12-7......2126'......Dv 31 FPS......60" x 1/4" (43" required)

I figured a lighter design would work better, and these first runs tend to confirm it. It was a pleasant surprise to see a D12-0 doing as well as it did as the booster, and to see a 500' difference in altitude between it and the E12-0. One item to note with these simulations, all three include a 3 oz allowance for a BoosterVision camera and 9V battery.
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #24  
Old 10-30-2011, 09:17 PM
CPMcGraw's Avatar
CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,357
Default

Using a standard Cherokee, I ran simulations with both 18" and 16.4" tubes:

Short-body: E12-6, 2018', Dv 29 FPS, requires 0.375 oz of ballast at base of NC, has a margin of 1.43. 28" of rod.

Long-body: E12-6, 1987', Dv 25 FPS, requires 0.25 oz of ballast at base of NC, has a margin of 1.45. 29" of rod.

The E12 requires ballast on both versions. The margin was below 1.0 for both without it.
__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635
Reply With Quote
  #25  
Old 10-30-2011, 11:10 PM
CaninoBD CaninoBD is offline
Craftsman
 
Join Date: Sep 2006
Posts: 131
Default

Quote:
Originally Posted by Green Dragon
You need no Level anything cert to cluster E motors.

Level 1 cert in only required for flying H-I motors. ( or up to cluster of 1280 N-sec ).

three 30Nsec E's is 90 Nsec and no certification is required..

unsure on the waiver issues, however, is the new no-notification 'large model rocket' propellant weight limit 125 grams or 113 ?

~ AL

fly em high


Not entirely correct.

Your forgetting the NAR safety code rule 7 Size. My model rocket will not weigh more than 1,500 grams (53 ounces) at liftoff and will not contain more than 125 grams (4.4 ounces) of propellant or 320 N-sec (71.9 pound-seconds) of total impulse.

3 E9 are 35.8 * 3 = 107.4 grams OK
4 E9 are 35.8 * 4 = 143.2 grams NOT OK - HP and you need a L1
Reply With Quote
  #26  
Old 10-31-2011, 12:13 AM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
BAR
 
Join Date: Dec 2007
Location: Needville and Shiner, TX
Posts: 6,134
Default

Quote:
Originally Posted by Doug Sams
Yes, indeed, this is great news! WFK!

I just compared it to the E9. Same length case. E12 has 2.5s burn time vs 3s for E9. Both have sustainer portion of curve at ~10N. Both are ~36g of propellant (ie, no mailing).

The key diff is that the E12 has a 33N initial thrust spike vs 20N for the E9. So the E12 is very much like a longer burning D12 with a similar initial kick.

I'm really looking forward to getting my hands on some of these! This is really exciting news.

Doug


I don't quite follow this...

The D12 burn duration is 2.7 seconds, is it not?? The E9 is 3 seconds, correct?? So the E12 is now 2.5 seconds, with the same peak thrust as a D12?? How is this a higher performing motor (IOW an "E" motor) if it has the same DURATION as a D12 and the same peak and average thrust as D12?? I get it that it's a LOW END "E" motor, so it's not going to be double the duration of a D12 at the D12's average and peak thrust levels to be a "full E", or that it has DOUBLE the peak and average thrust for the same duration as a D12, (or some combination thereof) but I don't follow how this is an "E" motor if it has the same burn characteristics as a D12... and the D12 at 17N/s isn't a FULL "D" motor either...

I must be missing something... Last I heard though, thrust times duration = total impulse (motor letter class) later! OL JR
__________________
The X-87B Cruise Basselope-- THE Ultimate Weapon in the arsenal of Homeland Security and only $52 million per round!
Reply With Quote
  #27  
Old 10-31-2011, 12:36 AM
Royatl's Avatar
Royatl Royatl is offline
SPEV/Orion wrangler
 
Join Date: Mar 2005
Location: Atlanta, GA
Posts: 2,645
Default

Quote:
Originally Posted by luke strawwalker
I don't quite follow this...

The D12 burn duration is 2.7 seconds, is it not??

....snip....

I must be missing something... Last I heard though, thrust times duration = total impulse (motor letter class) later! OL JR


Yep, you're missing something. The D12 is 1.6 seconds. The E12 burns 50% longer.
__________________
Roy
nar12605
Reply With Quote
  #28  
Old 10-31-2011, 06:27 AM
GregGleason's Avatar
GregGleason GregGleason is offline
U.S. Manned Space Program Buff
 
Join Date: Mar 2009
Location: Houston
Posts: 1,298
Default

The thrust curve is similar to the D12, except it burns for another second.

Remove the ".txt" from the file "Estes.E12.eng.txt" and you will have a working .eng file.

Greg

Quote:
; NAR Date Tested ...: 2011-09-25
; Total Impulse .....: 27.24 n-s (s 0.35)
; Peak Thrust .......: 33.29 n (s 3.49)
; Burn Time .........: 27.24 n-s (s 0.35)
; Average Thrust ....: 11.17 n
; Exported using ThrustCurveTool, www.ThrustGear.com
; Exported by .......: Greg Gleason
; Export Date .......: 2011-10-30

E12 24 95 0-4-6-8 0.0359 0.0588 ES
0.017 2.222
0.064 6.519
0.103 11.556
0.163 19.704
0.202 25.481
0.245 31.259
0.284 32.889
0.296 30.667
0.309 27.407
0.331 20.889
0.352 15.407
0.387 13.333
0.464 11.852
0.657 10.667
0.842 10.37
0.889 9.778
1.125 10.074
1.297 9.481
1.323 10.37
1.336 9.481
1.74 9.333
2.04 9.185
2.143 9.185
2.174 10.222
2.199 9.481
2.332 9.63
2.371 9.926
2.397 6.222
2.431 2.222
2.44 0.0
Attached Thumbnails
Click image for larger version

Name:  MtrCompare_D12.ES_E12.ES_E9.ES_C6.ES.jpg
Views: 110
Size:  151.3 KB  Click image for larger version

Name:  MtrData_D12.ES_E12.ES_E9.ES_C6.ES.jpg
Views: 85
Size:  172.6 KB  
Attached Files
File Type: txt Estes.E12.eng.txt (846 Bytes, 73 views)
Reply With Quote
  #29  
Old 10-31-2011, 07:03 AM
STRMan's Avatar
STRMan STRMan is offline
Master Modeler
 
Join Date: Nov 2007
Posts: 873
Default

Quote:
Originally Posted by Gus

So E12-0 to E9-8 ought to make for some interesting flights.


My first thought! I actually have an upscale Centuri Stiletto that I made to launch from a D12-0 to an E9-8. Rocksim put it up at around 2900 feet. I have to make another booster now to hold the E12-0 booster. Looks like I will finally have my first rocket capable of breaking 3000 feet!

It will be interesting to see if the sustainer will gain more altitude with an E9-8 or an E12-8.
__________________
"AND I hope they are from the planet of the "Chunk spunky Mary-Lou Retton clones". - Ironnerd

"Those who trade liberty for security have neither" - Benjamin Franklin

"Semroc is almost always the answer" - Stefanj

www.paulsavia.com

www.soundclick.com/paulsavia
Reply With Quote
  #30  
Old 10-31-2011, 09:33 AM
Doug Sams's Avatar
Doug Sams Doug Sams is offline
Old Far...er...Rocketeer
 
Join Date: Mar 2005
Location: Plano, TX resident since 1998.
Posts: 3,965
Default

Quote:
Originally Posted by Gus
So E12-0 to E9-8 ought to make for some interesting flights.
I have a rocket that's perfect for this. I used a Big Betty to build a sort of upscale ApogeeII, and, the way I set it up, the booster can handle the longer motor, so I should be able to test this combo...without putting it in orbit

BTW, I wasn't clairvoyant - I didn't anticipate the advent of a longer booster motor. I only made the booster longer, as I recall, to keep it closer to scale. But it oughta work perfectly with the E12-0.

Doug

.
__________________
YORF member #11
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 10:37 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024