complex L record attempt?

[The_Quacken]

I want to get a record and im an L2 flyer so I decided on the complex L record. I think its a good mix of go high and not too expensive. current very early design is based off of two wildman mach 2 rockets one with slightly modified fins. i did this cause the mach 2 is A) dirt cheap. and B) proven to some extent.
heres the current very quick and dirty sims

given the current complex L record seems to be set at about 35k feet i should snag it easily given no one beats it by an unbelivable margain



my current motor selection is a k250-k1050 if i can find both otherwise i may substitute for k455-l1000 which is similar in terms of altitude. next stop is to purchase 2 wildman mach 2's

As for planning stuff I Have no clue how I want to do upper stage ignition as the k250 has really weird grain geometry so idk about head end ignition


the grain looks like it could maybe do head end ignition but im not sure how id set it up . I may bond in an igniter to a non plugged closure and then the closure could just be recovered by dissolving the potted igniter wires out with epoxy but that feels sketchy. if anyone knows a method to do this on at forward closures.
I will also need a custom rear closure that's been turned flush so I could use the motor as a coupler

I do know of one other rocket that i assume will be going for this record (and would likely absolutely beat it if/when it has a successful flight) but as the record stands this will be plenty and also not bust waivers at far or balls

additionally both stages will be single break single deploy likely flying a mix of eggfinder and featherweight products. thats mostly budget dependent.

 

[The_Quacken]

well ive been informed that one of the motors I wanted to use is OOP so rip that. there are plenty of non oop options tho that will slam the record according to sims

 

[The_Quacken]

anyways if anyone has a k 1050 lying around ard would consider selling it

 

[StreuB1]

Try an L1090W to a K270W

Still within the L range at 4639ns

 

[The_Quacken]

Try an L1090W to a K270W

Still within the L range at 4639ns

This is a good setup but I think k1275 to l1000 has more impulse at 4840 and I’m more confident I can get a dms to be modified to remove the thrust ring within mfg specs

 

[watheyak]

Does head- end ignition make the motor EX? That might factor in to your ignition decision.

 

[tfish]

Does head- end ignition make the motor EX? That might factor in to your ignition decision.

There are currently no certified motors that come with head end ignition.

So, the flyer adding it to a motor will make the motor and flight a Research flight.

Research flights can be conducted by Tripoli L2 members at "most" Tripoli events.

Tony Alcocer
Tripoli Research Team

 

[rocketace]

I think what watheyak is getting too is that only certified motors are allowed for the record attempts and modifying for HEI would break that rule.
I had the same thought when I started my similar (almost identical) project.

 

[watheyak]

There are currently no certified motors that come with head end ignition.

So, the flyer adding it to a motor will make the motor and flight a Research flight.

Research flights can be conducted by Tripoli L2 members at "most" Tripoli events.

Tony Alcocer
Tripoli Research Team

Ah yeah true for the record attempt it makes a difference. But you know that

 

[StreuB1]

This is a good setup but I think k1275 to l1000 has more impulse at 4840 and I’m more confident I can get a dms to be modified to remove the thrust ring within mfg specs

The idea that the maximum number of newtons will achieve the highest altitude is a proven flawed idea. It is how you expend those newtons relative to the vehicle and flight profile. The thrust to mass ratio of the vehicle at specific altitudes and specific velocities is core to optimizing ultimate altitude.

 

[The_Quacken]

The idea that the maximum number of newtons will achieve the highest altitude is a proven flawed idea. It is how you expend those newtons relative to the vehicle and flight profile. The thrust to mass ratio of the vehicle at specific altitudes and specific velocities is core to optimizing ultimate altitude.

Sims also say the motors I chose go higher. The k1275 has enough thrust to get the whole stack moving to get the L lit at a decent altitude I intentionally tried to pick the highest thrust k possible

Does head- end ignition make the motor EX? That might factor in to your ignition decision.

I won’t be doing head end ingition. Current plan involves a copper tape system along the outside of the motor. The only issue would be threading witted into the e bay as that will likely be pinned in somehow. I may use short machine screws to attach the e bay tho so that would solve that. It’s gonna be somewhat fiddley to integrate so we’ll see how that works

Anyways the plan is to set up the motor by putting copper tape down both sides and then soldering on leader wires on one end and the igniter on the other (outside of the motor obviously) then the igniter could be threaded in after the motor has been slid into the airframe and the leader wires threaded through the aft bulkhead into the e bay

 

[StreuB1]

What happens when you boost on the L and sustain on the K?

Generally boosting hard to then do a long duration coast into thinner air then lighting the longer burning, and generally lighter weight sustainer, yields highest apogees. Not always though.

 

[The_Quacken]

What happens when you boost on the L and sustain on the K?

Generally boosting hard to then do a long duration coast into thinner air then lighting the longer burning, and generally lighter weight sustainer, yields highest apogees. Not always though.

I tried that and I generally seem to get a better altitude boosting the L in my sim. I’m kinda limited on motor selection for the sustainer (no cti at all due to outside threading, aerotech rms will require me to get manufacturer aproved motor modifications, and the budget is too tight for Loki engines) I think it’s cause the L has a longer burn and the impulse can be used more efficiently at 15k asl than 5k asl

 

[boatgeek]

I tried that and I generally seem to get a better altitude boosting the L in my sim. I’m kinda limited on motor selection for the sustainer (no cti at all due to outside threading, aerotech rms will require me to get manufacturer aproved motor modifications, and the budget is too tight for Loki engines) I think it’s cause the L has a longer burn and the impulse can be used more efficiently at 15k asl than 5k asl

CTI (nominally) makes a tapered closure for the 54mm cases. Can you find one of those? AMW and Apogee show out of stock, but someone else might have one, especially if you ask in the yard sale.

 

[The_Quacken]

CTI (nominally) makes a tapered closure for the 54mm cases. Can you find one of those? AMW and Apogee show out of stock, but someone else might have one, especially if you ask in the yard sale.

i need the closure to match the diameter of the motor casing so im not sure that would work since there needs to be some meat to grip the threads

 

[watheyak]

i need the closure to match the diameter of the motor casing so im not sure that would work since there needs to be some meat to grip the threads

A while back RouseTech made a flush closure for 38mm Aerotech hardware. Since they were technically a licensed Aerotech manufacturer, that closure didn't affect the certification of the motor.

As far as I know, no one ever made a similar closure for 54mm. Unfortunately turning down the existing closures flush with the OD of the case would bring you back into the EX realm, and be no good for the record.

I could be wrong, there may be a 54mm flush closure out there. I know there have been plenty of 2-stage minimum diameter projects.

Your other option is just to go for an EX record and have fun with head end ignition and slightly modified hardware.

I hate to be a downer, but it would be a bummer to put a bunch of effort into a design and then have to change it.

 

[The_Quacken]

A while back RouseTech made a flush closure for 38mm Aerotech hardware. Since they were technically a licensed Aerotech manufacturer, that closure didn't affect the certification of the motor.

As far as I know, no one ever made a similar closure for 54mm. Unfortunately turning down the existing closures flush with the OD of the case would bring you back into the EX realm, and be no good for the record.

I could be wrong, there may be a 54mm flush closure out there. I know there have been plenty of 2-stage minimum diameter projects.

Your other option is just to go for an EX record and have fun with head end ignition and slightly modified hardware.

I hate to be a downer, but it would be a bummer to put a bunch of effort into a design and then have to change it.

yeah if it cant fly the standard record i may put it in the ex category ( even if its a little lame to do that just because its a slight modification and I did no real work on the motor). at the end of the day this rocket is just to push as high as I can with limited impulse and records arent truly what matters to me

that said I was looking to get the modification aproved by aerotech or posibly even manufactured by them. I will have to wait until LDRS aftermath is settled to get through to them. ideally this would make my life easy

 

[GalantVR41062]

You could make a "tailcone" for the single use L1000. Starting on post #67:
https://www.rocketryforum.com/threa...ase-with-a-nose-cone-and-4-fins.162266/page-3
Then run the tailcone rear closure for the sustainer. A little time on the lathe and detailing (paint or polish) could modify just the OD/thrust ring area to match the sustainer airframe.
https://wildmanrocketry.com/products/54tc
Other motor choices: Loki L1400LW booster and Aerotech K375NW sustainer only leaves 41.26Ns on the table.

 

[Neutronium95]

I've been gradually growing less interested in building rockets within the record rules these days. Stuff like HEI or flush rear closures might disqualify a flight from being an official record, but could make the rest of the rocket simpler or more optimized. If one of my high performance projects meets the requirements to be a Tripoli record, that's great, but if changes to the motor make the design simpler, or give more performance I'll go that direction every time.


For example, I've been hearing some rumors that fins bonded to motor cases, like on my attempt at the H record in January, might not be allowed for records in the future. Even if they change the rules, I'll still be building my high altitude rockets this way, because it's less drag than a fin can.

 

[The_Quacken]

I've been gradually growing less interested in building rockets within the record rules these days. Stuff like HEI or flush rear closures might disqualify a flight from being an official record, but could make the rest of the rocket simpler or more optimized. If one of my high performance projects meets the requirements to be a Tripoli record, that's great, but if changes to the motor make the design simpler, or give more performance I'll go that direction every time.


For example, I've been hearing some rumors that fins bonded to motor cases, like on my attempt at the H record in January, might not be allowed for records in the future. Even if they change the rules, I'll still be building my high altitude rockets this way, because it's less drag than a fin can.

I like this philosophy like yeah it’s cool to have ur name on the site but yk it’s also cool to see how much you can actually push a rocket

 

[watheyak]

I like this philosophy like yeah it’s cool to have ur name on the site but yk it’s also cool to see how much you can actually push a rocket

And given that the records tracking has been watered down a bit, this philosophy sounds more appealing.

Maybe us altitude junkies could start our own records list. I'm currently working on a new TRAPHX website. It could have a home there. Just a suggestion. I'll derail this thread no further.

OH! I also wanted to second the observation that Loki motors have a removeable thrust ring. They also increase the "cool factor" of the rocket.

 

[The_Quacken]

OH! I also wanted to second the observation that Loki motors have a removeable thrust ring. They also increase the "cool factor" of the rocket.

i really want loki casings.... im a little too broke tho

that said i think imma put this project on a slight hold while I gain more staging experience and also money. maybe ill shove some Ls in the airframe and go for the M record (sims say that might break 100k) but yeah I would love a dedicated just absolute no holds barred altitude record site. btw ive been meaning to make it to TRAPHX cause yall have a good waiver and a good site from what I hear