Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > The Golden Age of Model Rocketry > Model Rocket History
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #41  
Old 03-18-2015, 01:25 PM
snaquin snaquin is offline
The_Ripper
 
Join Date: Jun 2005
Location: Louisiana
Posts: 1,941
Default

Quote:
Originally Posted by BEC
The source of that figure is the little graph on the last page here: http://www.oldrocketplans.com/enerj...340/enj1340.pdf

This is a very light rocket for a G (even with a half-pound payload). Couple that with a long burning motor and it seems plausible (subject to actually looking at a detailed simulation, anyway). The graph is total impulse on the X axis and altitude on the Y axis with two curves for two different payload ranges. It doesn't specify any particular motors. The 6-12 ounce payload curve crosses the 10000 foot altitude line at 40 lb-s. That's 178 N-s, which, I guess isn't a G but a baby H.


I'm going to chance an altimeter in my next 1340 flight, an inexpensive unit or my Pnut to get data. On long burn Ellis G35-10 the 1340 and 1340/20 [I still have a couple left] because the motors are low smoke you can hear the model still under thrust but lose site of it after a couple of seconds into the burn. These are very high altitude models I really need to capture some data.

Any other suggestions for an inexpensive recording altimeter choice other than the Pnut since you have personally tested most altimeter models in flight? I have a couple of Stratologger [not the CF] and Pnuts in the range box. What is the least expensive altitude only if i don't want to risk my PerfectFlites?

.
__________________
Steve Naquin
TRA# 677 L2
NAR# 85518 L2
SAM# 0052

🚀 In Construction: Der Blue Maxx/Minie-Magg 5.5” & Vander-Burn MDRM Clone w/Stickershock23 Custom Decals
🚀 In Paint & Detail: USR Banshee
🚀 In Build Queue: Estes Doorknob w/Vander-Burn Rocketry Upgrade Kit [Sport Decor], Semroc Centurion-F, Semroc Egg Crate
🚀 In Repair: SLS Lil’ Hustler, SLS Aero-Dart 1969 Trim
🚀 Stay Tuned For Fall 2021 Launch Dates
Reply With Quote
  #42  
Old 03-18-2015, 01:42 PM
BEC's Avatar
BEC BEC is offline
Master Modeler
 
Join Date: Feb 2009
Location: Auburn, Washington
Posts: 3,643
Default

Quote:
Originally Posted by snaquin

Any other suggestions for an inexpensive recording altimeter choice other than the Pnut since you have personally tested most altimeter models in flight? I have a couple of Stratologger [not the CF] and Pnuts in the range box. What is the least expensive altitude only if i don't want to risk my PerfectFlites?


If you want recording, the only less expensive option really is the Altus Metrum MicroPeak. But after you buy the interface to get the data out you're well past the price of getting another Pnut ($58.46 plus shipping at perfectflitedirect.com). I presume you have the PerfectFlite interface device already.

For altitude only the new FireFly from PerfectFlite (at least once they come back in stock) is the best bang for the buck right now, in my opinion.

The MicroPeak is half the size and mass of the FireFly so your 1340 would never know it's there....but a Pnut isn't all that massive.
__________________
Bernard Cawley
NAR 89040 L1 - Life Member
SAM 0061
AMA 42160
KG7AIE
Reply With Quote
  #43  
Old 03-19-2015, 08:21 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

As a possible alternative (or as a back-up/comparison) to an onboard altimeter, what about flying a 1340 at night, with a strobe light mounted inside an un-painted nose cone? With two azimuth-elevation trackers (or three elevation-only trackers, as per the method covered in G. Harry Stine's "Handbook of Model Rocketry"), the altitude could be determined trigonometrically. Also:

The rocket's position could also be compared against the (angular) altitudes of selected stars (whose altitudes could also be measured using the trackers, as well as being checked with an ephemeris or a planetarium computer program). This could be done at leisure by photographing the rocket and the selected stars. Recording the rocket's exhaust- and strobe-illuminated path on time-indexed video would also provide another way to determine its velocity ("mach-buster" model rocket experimenters often use this method). In addition:

Recovering the rocket could be facilitated by using one or more aluminized mylar parachutes, into which bright LED lights (tied to the shroud lines' converging point at the "load" end of each 'chute) would shine upward, using the parachute canopy as an analog of a car headlight's parabolic reflector.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
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 07:17 AM.


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