3" BMS School Rocket - Anyone flown it using an Aerotech F67W or G74W?

[Johnly]

The local college group is flying the 3" BMS school rocket with H195T DMS motors with delay adjusted for 10-11 seconds for their L1 HPR certifications. Needless to say the rocket really scoots with this motor, but they have located a smaller local field that they can fly on and I was thinking that a F67-4W or the G74-6W would work for this venue. Anyone have some flight experiences they could share? They are planning on purchasing 100+ motors for student use, and I would like to locate real data rather than just simulation results.

 

[user 35280]

The local college group is flying the 3" BMS school rocket with H195T DMS motors with delay adjusted for 10-11 seconds for theirt L1 HPR certifications. Needless to say the rocket really scoots with this motor, but they have located a smaller local field that they can fly on and I was thinking that a F67-4W or the G74-6W would work for this venue. Anyone have some flight experiences they could share? They are planning on purchasing 100+ motors for student use, and I would like to locate real data rather than just simulation results.

That must be their upgraded 3” diameter school rocket? The one I have has a 24mm motor mount. It’s marginal at best on a E12-4 BP motor, but launches and recovers great on a SU AT E20-4.

 

[Back_at_it]

I've flown the F67-6 in my 3" 29mm School Rocket once. It really left the pad hard. No altimeter on that flight but I'm guessing 1100ft. I can tell you that the E30 is a great motor in that rocket. I do have an altimeter flight with that motor and saw 603 ft.

 

[nict]

I recently got this rocket, with the optional payload bay. I plan to start the build soon.

 

[waltr]

I have the longer, 29mm school rocket. Flown on F39 (24mm case with Estes orange adapter).
Added the payload section with a 10DOF IMU and GPS. Flown this with F67 to 750'.

The short school rocket on an F67 could reach 1100'.
Look into E motors. OR sim shows an E18-5W going to 740' and leaving a 1.8m rail at 15m/s.

 

[dhbarr]

Since most folks tend to overbuild, my gut says g76 green.

 

[nict]

I'll be adding a full electronics bay as well. Much time will be spent on thrustcurve once completed.

Mind sharing the OR file?

 

[waltr]

I'll post the OR files tonight.

Currently I am building a 2-stage School rocket with Airstart.
Using the short school rocket for the booster and the long one for upper stage.
Bought a few extra 3" couplers to make the inter-stage and the electronics bay.
I'll post this one too.

 

[Back_at_it]

I have a couple of the 29mm 3" School Rockets as well as their 24mm version. Both great rockets and an almost unbelievable price.

My most common flown 29mm version currently has 4 flights. The rocket packed ready to go minus motor weights 13.3oz. My CG is at the 18.125 mark and my CP is at 21.900. Parachute is 18". All launched off a 6ft 1/4" rod.

Looking back at the notes from my flight log.

- E20-4 - Great flight but the ejection was just a tad early. No damage. Recorded 613ft.
- F44-8 - Screamed off the pad. Ejection a tad late. No damage. Recorded 806 ft.
- F67-6 - Left pad hard. Ejection was way early. No damage. Recorded 1216 ft.
- E30-4 - Left pad hard. Good timing on ejection. No damage. Altimeter failed so no altitude on that flight.

Over all I'd say the F67-6 is a good motor for that rocket if you have the room to recover a 1200 ft. apogee. If space is concerned the E20 or E30 would be my choice.

 

[waltr]

Ok, as promised here are the OR files I have. Someone posted the short version a while back.

 

[roytyson]

Has anyone flown this on an CTI H53? I have a friend considering this for a L1 cert flight.

 

[waltr]

Has anyone flown this on an CTI H53? I have a friend considering this for a L1 cert flight.

Is this the short (standard 17" BT) 3" school rocket) It sims to over 3000 feet on a CTI H53. But motor uses most of the space required for chute so no go.
If exteneded (34" BT) then plenty of length for motor and chute. Still over 3000 feet but if filed is large enough for recovery it'll be ok.
Both sizes have enough speed off the rail.

Has your friend done the simulation in Open Rocket??? If going for their L1 cert then they should be running sims to know what to expect. Besides appogee, they should know speed off rail, where the CP & CG are and the stability margin. Then have an idea of how far it will drift in wind under chute.

Open Rocket files for this rocket are posted above so no reason not to be running sims.

 

[teepot]

I think the BMS 3" School Rocket is a great rocket. Body tubes are lighter than LOC tubes, but thicker than Estes tubes. They have pre-slotted body tubes and plywood fins that are TTW. Plus you can buy one with an additional body tube for a longer rocket. I have built a couple for them to make sure the directions are correct and make sense. I gave them back when I was done. I have another one I'm going to donate to our club for the next raffle. I should probably build one and keep it. I get all most everything from BMS. Body tubes, full length couplers {34"}, nose cones, plywood, balsa and motors. I should tell you that they are 5 minutes from me.

 

[Karlcullen]

Is this the short (standard 17" BT) 3" school rocket) It sims to over 3000 feet on a CTI H53. But motor uses most of the space required for chute so no go.
If exteneded (34" BT) then plenty of length for motor and chute. Still over 3000 feet but if filed is large enough for recovery it'll be ok.
Both sizes have enough speed off the rail.

Has your friend done the simulation in Open Rocket??? If going for their L1 cert then they should be running sims to know what to expect. Besides appogee, they should know speed off rail, where the CP & CG are and the stability margin. Then have an idea of how far it will drift in wind under chute.

Open Rocket files for this rocket are posted above so no reason not to be running sims.

Unfortunately I did something like that and got that either I didn't make some corcet, or it didn't work, but I failed to make the correct trajectory. Probably best to check this with someone who knows.

 

[waltr]

Unfortunately I did something like that and got that either I didn't make some corcet, or it didn't work, but I failed to make the correct trajectory. Probably best to check this with someone who knows.

I really have no idea what you are saying...
What didn't work?
What about the trajectory failed?

 

[thzero]

The local college group is flying the 3" BMS school rocket with H195T DMS motors with delay adjusted for 10-11 seconds for their L1 HPR certifications. Needless to say the rocket really scoots with this motor, but they have located a smaller local field that they can fly on and I was thinking that a F67-4W or the G74-6W would work for this venue. Anyone have some flight experiences they could share? They are planning on purchasing 100+ motors for student use, and I would like to locate real data rather than just simulation results.

Hope they have either a really large field, or are using some sort of dual recovery (i.e JollyLogic ChuteRelease or other)... based on Waltr's files, it sims to 2900' feet. Even a smaller H128W is still 2300'. It is after all probably under 20oz at most without the motor dependency on amount of overbuilding.

 

[Karlcullen]

Is this the short (standard 17" BT) 3" school rocket) It sims to over 3000 feet on a CTI H53. But motor uses most of the space required for chute so no go.
If exteneded (34" BT) then plenty of length for motor and chute. Still over 3000 feet but if filed is large enough for recovery it'll be ok.
Both sizes have enough speed off the rail.

Has your friend done the simulation in Open Rocket??? If going for their L1 cert then they should be running sims to know what to expect. Besides appogee, they should know speed off rail, where the CP & CG are and the stability margin. Then have an idea of how far it will drift in wind under chute.

Open Rocket files for this rocket are posted above so no reason not to be running sims.

Being a college student, we have to do writing on this assignment with data we got from tests; besides this I decided to be smarter and started using https://edusson.com/ which we use to do custom essay on rockets, this helps us a lot because we don't have to spend a lot of time to do studies for college.

Sorry, I expressed myself unclearly, I had in mind that the files that are above, or do not work correctly or I do something not so.
Says that the test will fail.

 

[waltr]

Sorry, I expressed myself unclearly, I had in mind that the files that are above, or do not work correctly or I do something not so.
Says that the test will fail.

Still unsure of what you are trying to say.

Are you opening the sim *.ork files in Open Rocket V22 beta 5? These do work and someone else has run the sim.

"Says that the test will fail".
What does this mean??? What is the EXACT message from OpenRocket?

 

[Karlcullen]

I mean the rocket didn't fly at the points I wanted it to. Probably still a mistake of mine, sorry