#1
|
||||
|
||||
Q-Jet motor max lift weights ?
The max lift weights of the C Q-jets seems very low to me? Less than 4oz?
Estes C5-3 is rated at 8oz Estes C11-3 is rate at 6oz Any thoughts? C18-4 W Motor Diameter: 0.698" (18mm) Casing Length: 2.75" (70mm) Total Impulse: 9.8 N-sec Burn Time: 0.52 seconds Average Thrust: 18 newtons Delay Time: 4 seconds Propellant Weight: 5.6 grams Propellant Type: White Lightning Motor Weight: 20.9 grams Maximum Liftoff Weight: 113 grams D16-4 BJ Motor Diameter: 0.698" (18mm) Casing Length: 2.75" (70mm) Total Impulse: 12.4 N-sec Burn Time: 0.79 seconds Average Thrust: 16 newtons Delay Time: 4 seconds Propellant Weight: 9.9 grams Motor Weight: 25.7 grams Maximum Liftoff Weight: 128 grams
__________________
======================= If the Sky is the Limit, then, why is there Footsteps on the Moon? ======================= |
#2
|
|||
|
|||
I’ve always treated max liftoff weight as a guideline more than a rule - a small diameter, low drag rocket over the limit by a bit (on a calm day) will probably be fine, while a lighter but draggy rocket may not work well at all. I’ve used the initial version C/D QJets in heavier, low drag rockets and they’ve worked well, while my Estes 1/200 RTF Saturn V definitely doesn’t like the D motors. What I haven’t tried, other the the SV, is heavy draggy rockets over a C/D QJet.
|
#3
|
||||
|
||||
I'm looking forward to the C18 and D20 as well.
Will try the short delay ones of each in my Mars Landers then get a bulk-pak of Ds. Might even get out one of my old 1284 Space Shuttles to try the Ds too.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, and HAVOC ! |
#4
|
||||
|
||||
Quote:
They will be particularly good for heavier Outlander models.
__________________
I love sanding. |
#5
|
|||
|
|||
Quote:
My Looney Tunes equivalent of the Red Giant and my MPC Enterprise both work great on QJets. Love using the D motors with an adapter in my Estes Vagabond, the faster takeoff is a fun change from the slower BP launches. |
#6
|
||||
|
||||
I think the weights on the Q-jet As and Bs should be heeded. I started out trying to fly models that flew well on Estes B6-4 but were too heavy for the Qjet B4-4.
There is a mistake in The Cs max weight recommendation since the C12-4 and C12-6 are both listed at 113 g. 200 would probably be a good number for C12-4. The C18 uses the same flawed recommendation for 4s and 6s. The C18 and D20s should probably also be higher since they have double the initial thrust. Beyond that, the delays for the 4 sec are a full four or more. The C5-3 is the exception but the delays for Estes are usually shorter than listed. As long as it’s low enough to be safe. |
#7
|
|||
|
|||
Quote:
The QJet C motors work fine in my RTF SV but for some reason it just doesn’t fly right on the D motor - I get a squirrely tail waggle that doesn’t happen on a C motor. If I ever get one of my Dr. Zooch Saturns done the 1/200 Estes is being retired to display status anyway so it’s not that big of a problem. |
#8
|
||||
|
||||
Quote:
Check the nozzles on the D, I have had the nozzle surface and a bit of throat break out of a C and D. There was a pronounced jog in the flight path and both flights seemed lower than normal. Last edited by 5x7 : 11-18-2020 at 02:10 PM. |
#9
|
||||
|
||||
I like the specs on the D20-4 W
Specifications: Motor Diameter: 0.698" (18mm) Casing Length: 2.75" (70mm) Total Impulse: 13.8 N-sec Burn Time: 0.76 seconds Average Thrust: 20 newtons Delay Time: 4 seconds Propellant Weight: 8.7 grams Propellant Type: White Lightning Motor Weight: 24.1 grams Maximum Liftoff Weight: 340 grams Almost 12oz
__________________
======================= If the Sky is the Limit, then, why is there Footsteps on the Moon? ======================= |
#10
|
|||
|
|||
Quote:
That’s going to be a great motor for bigger model rockets! More incentive to get my Estes Shuttle and Pemberton Kraken built and my slightly crashed Executioner repaired. |
Thread Tools | Search this Thread |
Display Modes | |
|
|