... this is the essence of your Level 1 Odyssey, grasshopper. when you have been emptied of knowledge, the correct motor will choose you. (vanish in clouds of smoke)
did you give your rocket a test flight on a G motor? no worries! enjoy!
Going for level 1 soon....
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did you give your rocket a test flight on a G motor? no worries! enjoy!
Yes, I've flown it on a AT G76 ....got 800'...was a decent flight...rsbhunter
Not trying to change your mind on the cert flight, only clarifying a point to ponder:
Total impulse for any 29/180 H-impulse load will be very similar (170-175Ns). Therefore, they would reach similar altitudes.
With a higher thrusting motor like the Blue Thunder load, the rocket would get moving more quickly, but then the motor would burn out more quickly. You'd still see the whole flight with an H165R or H238T. They would just get off the pad quicker.
Good luck!
terryg
Well-Known Member
Get the 29/180 case, functionally it is not that different fom the hobbyline case you are already using. Balsa Machining Services has a $16 flat rate shipping for nonhazmat reloads. You will not regret it!
That was the case/motor 'everyone' had for the next step above the 29/40-120. I've loaned mine out many times over 2 decades*, and still will if the need arises.
But you would need to get "The Complete Motor". As your closures from the Hobby Line do not fit the HPR motor line.
The RMS H165R is the lowest NS , at 161ns it is really just a full G motor.
The H128W is 178ns
The DMS H135W is a little more NS then H128 Reload at 229ns.
Which one to use? It depends on if you want a Red Laser Beam under the Rocket in your L1 Liftoff Photo, or a Cloud of Smoke.
*Well way back in the day in a field far away, before the 29mm HPR reloads; we had Aerotech Single use H70s for Tripoli 'Confirmation' flights. One H motor and done. There were no levels at the time.
To get an Idea of inflation, the 29mm H70 single use was $16.95 list price, and less at discounts.
Dean from Rockets R&D signed my TRA confirmation card in 1989 at Danville Dare II. Here is that motor next to a brand new 29/180 motor case. I've lost my original. I do have my original 'well used' 38/240 Industrial Solid Propellent [ISP] motor serial number #125 still with the box set they came in at the time. Got it from Gary at a Danville Dare when they came out
Thanks for letting me re-live my first L1 flight this morning. When Levels came out I had to get my L1 again, as 'Confirmations' were then a thing of the past.
Edit: Both my 1989 'Confirmation' and later NAR L1 was on an NCR original non-Estes Big Brute. It suffered a Road Flare type CATO about 15 years ago.
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This is just advice I received, studied, and took to heart.
Lots of times you will hear "low and slow" which makes sense on the surface.
The legal minimum is 3 to 1 thrust to weight, most clubs stick at 5 to 1.
I was explained that 10 to 1 gets the rocket up to speed much quicker, the fins are in strong control as soon as the forward rail button leaves the rail.
A slow lift off allows much greater weather weathercocking with out a large corrective force from the fins untill it gets to speed.
Is it required? No sir. Have I had much straighter flights since? Yes.
Just food for thought.
In no way or form am I trying to tell you what to do. This advice has worked very well for me.
Also after you get your cert, do not hesitate to try dual deploy, it really is where it is at. It is not near as difficult as I imagined, and sets rockets down close.
Also good luck! I was over the moon for a week when I got my L1.
Steve
Lots of times you will hear "low and slow" which makes sense on the surface.
The legal minimum is 3 to 1 thrust to weight, most clubs stick at 5 to 1.
I was explained that 10 to 1 gets the rocket up to speed much quicker, the fins are in strong control as soon as the forward rail button leaves the rail.
A slow lift off allows much greater weather weathercocking with out a large corrective force from the fins untill it gets to speed.
Is it required? No sir. Have I had much straighter flights since? Yes.
Just food for thought.
In no way or form am I trying to tell you what to do. This advice has worked very well for me.
Also after you get your cert, do not hesitate to try dual deploy, it really is where it is at. It is not near as difficult as I imagined, and sets rockets down close.
Also good luck! I was over the moon for a week when I got my L1.
Steve
Yes sir...thought about going to 38mm to cert, but to save $50-71.00 per reload order, I'll stick with 29mm hp. Two non hazmat orders will pay for my 29/180 case assy. I definitely appreciate all the input, advice, but especially the knowledge that you gentlemen are willing to share...rsbhunter
No sir, I agree 100 percent !!! The first Estes hi flier xl I built when I first started rockets again, I learned that lesson. 10' high, 30 yards horizontal, then dirt city....is it total thrust , peak or average that you figure T/W ratio off of? Thanks, rsbhunter
Lift Off Thrust from the Thrust Curve drawing is the best for determining your speed off the launch rail.
Average thrust the second best and what most people use.
Some motors like an I65 long burn you need to use lift off spike
Also motors change, make sure you are using the most up to date version, or that which matches the motor you have , if you have an old motor.
Here is what the I65 looked like more then 2 decades ago. I have one of those old ones, that have an Aluminum case in a single use motor. That is part of the 'collection'
I have two of the plugged modern ones that I will fly at least one of in the next year or 2. Need to get to a field that I can fly it from.
Here is what the I65 looked like more then 2 decades ago. I have one of those old ones, that have an Aluminum case in a single use motor. That is part of the 'collection'
I have two of the plugged modern ones that I will fly at least one of in the next year or 2. Need to get to a field that I can fly it from.
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As always, you are here with the answer!!! Now, as i am NOT the brightest crayon in the box, is "lift off thrust" the top of the spike in the graph? I know they usually state , peak, max, average. Is peak the highest point of a graph? Hate to keep coming back with more questions, but you are very knowledgeable and helpful....Thanks, rsbhunter
Currently , I have forgotten much of what I used to know. [due to issues]
* TL/DR jump to the bottom for answer for most uses
John Coker has the calculated way to use it on his thrust curve site to calculate the speed off the rail, when you give the rail length. That is what is really important. There is also initial thrust listed in motor specs on the site.
For example, I put in my 3" 3 pound dry weight Caliber ISP LOC rocket with the newer I65 listed. [CS rocketry still has two in stock for folks that still want one, may be a long time to get another one]
It shows a 4:1 ratio. But I know at the same NSL Geneseo 2018 launch I last flew mine at, that 2 others flew theirs that weighed some more then mine. All I know is someone told me mine was the lightest and so those others would have been even less than 4:1 T/W
Here in the motor specs he has Initial Thrust, which is a little bit short of the max thrust. 37 pounds [165n initial] / 4.65lb of rocket with motor weight is 8:1. Which is more like what I see when that rocket is launched. Not A very Slooo liftoff that a 4:1 would have.
Lets take 18lbs [80n avg thrust] and / 4.65lb and we get 4:1, which is what that chart above shows as the T/W ratio. I would not launch that in the wind. Yet in 2018 NSL the RSO had us pointing the Rockets into the Wind to be away from the crowd by the time I launched my rocket. The wind was less when he launched his Caliber ISP-I65 that weighed a bit more, more close to straight up [Chris' Rockets had an ISP I65 contest going on]
Had the crowd not been on that side of the launcher I would have put it 'with the wind' to make a more straight up flight. The true 8:1 off the launch rail got that rocket up there where a true 4:1 would have been a bad idea.
*But for most motors, AVG thrust will work and be safe
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fixed it for ya.
You are the the type of person that honestly fits the description " has forgotten more than most know" Thank you for all you do for all of us...rsbhunter
Ok, just ordered the 29/240!!! Going to order the RAS and reload next month, fingers crossed I made the right choice!!!
Woo Hoo, @rsbhunter !
Congrats on your new NAR membership and your new club !!
I've never been there but I have heard that Alamagordo is a GREAT site.
Good luck with your upcoming L1 flight !!!
-- kjh
Congrats on your new NAR membership and your new club !!
I've never been there but I have heard that Alamagordo is a GREAT site.
Good luck with your upcoming L1 flight !!!
-- kjh
Does this still look like the Alamagordo field?
I flew an H RMS in my 1.9" AeroTech ISQY Tomahawk there on pad 32. Pop At The Top & walk recovery. About 14 years ago.
I flew an H RMS in my 1.9" AeroTech ISQY Tomahawk there on pad 32. Pop At The Top & walk recovery. About 14 years ago.
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I honestly haven't been there yet. I had convinced myself that mpr was enough fun...NOT!!! So now, I have ordered a 29/240 rms , and will order the RAS and 180mm reload to hopefully certify in January. I figured with what I'll save on hazmat ($50-70) on each reload order, I can fly 2-3 times as often. A gentleman here named Brady has put the effort into starting a local club, the Pecos Valley Rocketeer's....and we are working on finding a hp launch site...I just joined NAR, so I'm excited about becoming a poor hp rocketeer!!!! Will take , and post pictures after I return...rsbhunter
Congrats on the RMS 29/240 purchase.
That motor and the reloads for it are among my favorites.
And except for the H97J they all ( H180W, H210R, H220T, H250G ) should ship NO HAZMAT.
Then once you've got the RAS the H128W, H165R and H238T are NO HAZMAT too ( but like the H97J, the G75J is a HAZMAT motor ).
I've never owned an RAS system so I can't say much about it.
But being an old timer, I might be inclined to buy a 29/180 case only instead of the 29mm RAS system and start collecting used fwd and aft closures.
But that is probably just me because I don't know any better
-- kjh
That motor and the reloads for it are among my favorites.
And except for the H97J they all ( H180W, H210R, H220T, H250G ) should ship NO HAZMAT.
Then once you've got the RAS the H128W, H165R and H238T are NO HAZMAT too ( but like the H97J, the G75J is a HAZMAT motor ).
I've never owned an RAS system so I can't say much about it.
But being an old timer, I might be inclined to buy a 29/180 case only instead of the 29mm RAS system and start collecting used fwd and aft closures.
But that is probably just me because I don't know any better
-- kjh
No, I'm a hoarder, no, strike that, a collector as well. I've already considered that, as the PML AGM has a 29mm adapter from 38mm in it. Not being a tall rocket, I think a 180mm case might fit better. It's like Lego's, they sell PIECES!!!!. So I'll just buy a 180mm case. It's fun to have a hobby like this later in life....rsbhunter
I look at about the first .5 sec. Then that low side avg, then divide by 4.45 to get pounds of thrust. Try to keep that at 8 to 10 times mass with motor.
I hope that helps.
Yes, Thank you!!!rsbhunter
Some vendors have a list of Limited Quantity motors with no Hazmat.
https://www.buyrocketmotors.com/no-hazmat-eligible/
Good luck on the cert.
In May, I helped two students and a teacher with their L1. I bought the H128 for them since there were three of them. Two were successful.
https://www.buyrocketmotors.com/no-hazmat-eligible/
Good luck on the cert.
In May, I helped two students and a teacher with their L1. I bought the H128 for them since there were three of them. Two were successful.
Good luck - use a check list.
Yes!!! Honestly have one printed up...did it right after I launched and the jolly logic cr landed about 5 yards away from the rocket....at least it did release the chute...rsbhunter
Well that is good. When I mess up the JLCR I forget to turn it back on.
It's interesting that the H reloads cost just as much as the G reloads. It's also interesting that a J520 is non-Hazmat.
I just put together a G76 for another flight of the EZ-DD. I'll be trying shear pins for the main chute instead of the instructed Scotch tape. I was inspired by @Art Upton.
In September, I took the NAR Level 2 exam. I got the question, when is it okay to modify a motor, and the answer is when the manufacturer authorizes it. The funny part is that Karl Baughman from Aerotech was sitting four feet from me at the time.
My son also passed his TRA Level 2. Afterwards, we had GO fever and launched our rockets in between the haboob dust storms crossing the playa. Both had JLCR so didn't get too far in the wind. I mailed the two JLCR to Mr. Beans who gave them the spa treatment and now good as new.
Unfortunately the J520 has been relegated to the seasonal production list. I would have thought that a no-Haz J from Aerotech would have been a perennial best-seller, but evidently not.
