motor recomendation questions

[Jeepin4Him]

Hey folks,
This is probably a silly question but being a bit of a newb I dont' know any better
I was wondering how you guys keep in mind which rocket flies best on which motor? I've only got 5 built but I've already lost track of what flies on what I guess the same question could be asked for how many sheets of wadding go in for flights too.
Thanks for the help fellas...much appreciated.

 

[Karl]

Wadding , heres what you need I think.....

Body tube dia Squares of wadding

0.75" to 1.00" 2
1.00" to 1.25" 3
1.25" to 1.50" 4
1.50" to more 5 or more


But as for motors you should check outthis page for the Manufacturer's Recommended Motors.

Hope this helps
Karl

 

[adrian]

My usual guidelines for wadding:

• BT-5: 1 square, torn into quarters so it goes in (and comes out!) more easily.
• BT-20: 2 squares torn into quarters.
• BT-50: 3-4 squares
• BT-55: 5 squares
• BT-60: 6-7 squares
• BT-80: 7 double squares, or for preference, a heat shield or piston!

Motors: for a rocket with a standard 18mm mount, use a C to get it as far as possible, or a B if you want to be more certain of getting it back. Use a long delay (B6-6, C6-7) for particularly light, streamlined rockets; use a short delay (B6-2, C6-3) for particularly heavy or unstreamlined rockets. Most "normal" rockets will be alright on a middle delay (B6-4, C6-5), so try that and watch to see if it ejects the parachute significantly before or after apogee. Multi-stage rockets will normally use a long delay for the sustainer.

 

[Mike]

Originally posted by Jeepin4Him
I was wondering how you guys keep in mind which rocket flies best on which motor?

You could always write it on a sheet of paper with your rocket name/motor combination on. If you could keep it looking cool, you could try and write on a fin the recommended motors...I'm sure I heard of someone on here doing that.

 

[shreadvector]

Motors: look at the manufacturers recommended motors. Remember that a B is twice the power of an A and each time you go up a letter it doubles again. Next consider the number next to the letter since it's the average thrust. heavier models need a higher average thrust. (Everyone has a personal preference, but most look for a "thrust to weight ratio" of 3-to-1 or greater). After the dash is the delay time until ejection. Heavy or draggy rockets need a SHORT delay to avoid a crash and starting a fire.

Wadding: Fill a length of body tube equal to 2 or 3 times the diameter with fluffy wadding. Blow the wadding down the tube like a blow-gun. It should slide easy and go "THUNK" against the engine/motor mount or engine/motor stop. If it goes "THUNK" then you used the correct amount and it has formed a good gas seal/piston that will prevent the hot gasses from the ejection charge from reaching the recovery system.

Originally posted by Jeepin4Him
Hey folks,
This is probably a silly question but being a bit of a newb I dont' know any better
I was wondering how you guys keep in mind which rocket flies best on which motor? I've only got 5 built but I've already lost track of what flies on what I guess the same question could be asked for how many sheets of wadding go in for flights too.
Thanks for the help fellas...much appreciated.

 

[qMaxx]

Some people will write the recommended motors on the nose cone shoulder, or even (if there's room) on the aft centering ring.

 

[moocrew]

if you are capable...you could make a cool way to put the suggested motors on some sort of decal and "fit" in with the scheme of your roc.
...uh this would be similiar to what is done with the estes Swift 220 if you have built or seen that one before.

or if you don't wanna do that...you could write the motors on the chute...possibly the under side...or just write it on a piece of paper and cram it down in there....
might wanna take that out before you launch thou!

 

[Micromeister]

Jeepin:
For as long as I've been flyinjg Model rockets I've been keeping a flight log of EVERY model I fly. Infor includes ambient weather data, model number, date, motor(s) and observations.
in the front of the book is a list of every model I own, there number, compeletion date, ewt and all recommened motors. over the years these two items have proved well worth the time keeping them up to date. adding photos of the models make discussing them and related topics quick and easy

 

[Jeepin4Him]

Thanks for the help guys! Those are great suggestions

 

[Fore Check]

When flying Estes/Quest style Model Rockets, the B6-4 and the C6-5 are staples. Unless you're flying low and slow due to the size of your flying field (thus you'd be using A engines) you will probably burn more of those two motor sizes in an average assortment of 18mm powered rockets than anything else.

If the rocket is particularly light, or has a minimum diameter airframe, you will want to increase the delay (B6-6 or C6-7). Likewise, if the rocket is particularly large or heavy, you'll want to decrease the delay (C6-3).

As always, follow the manufacturer's reccomendations. Micromister's flight log suggestion is a good one - something like that of your own will help you get the "feel for it."

There are few mainstream rockets that you'd go wrong by putting a B6-4 or a C6-5 in it.

 

[firemanup]

Jeepin I keep a detailed inventory on the computer just in word format of each rocket.

It looks like this for each rocket..

Alpha, Estes

Built 8-21-02
12.25” Length
.98” Diameter
.8 oz Weight
12” Chute Recovery
Balsa Fins
1200’ Max Altitude
Motors: A8-3, A8-5, B4-4, B6-4
B6-6, B8-5, C6-5, C6-7

With over 90 some rockets it's proven invaluable.. I keep the complete list on paper in the front of my Tripoli Notebook...

I also keep all of my flight logs from EMRR on paper in my notebook and it goes with me to every launch.

It was a bear to make at first as i was over 75 rockets when i made it, but once I did it's simple to update, I update the computer version every time i build something new, and the paper version as I see necessary.

The paper version of the flight logs get updated after every launch, then I can see the manufacturer's suggestions as well as actual flight results with each rocket when i'm deciding on what to fly in what...

 

[loopy]

Originally posted by Fore Check
When flying Estes/Quest style Model Rockets, the B6-4 and the C6-5 are staples. Unless you're flying low and slow due to the size of your flying field (thus you'd be using A engines) you will probably burn more of those two motor sizes in an average assortment of 18mm powered rockets than anything else.

If the rocket is particularly light, or has a minimum diameter airframe, you will want to increase the delay (B6-6 or C6-7). Likewise, if the rocket is particularly large or heavy, you'll want to decrease the delay (C6-3).

As always, follow the manufacturer's reccomendations. Micromister's flight log suggestion is a good one - something like that of your own will help you get the "feel for it."

There are few mainstream rockets that you'd go wrong by putting a B6-4 or a C6-5 in it.

I couldn't agree more. With my low powered rockets, I only have a few rockets that don't fly on those two motors. The ones that don't, I happen to know what they do fly on. I also keep a flight log for every flight.

Loopy